diff --git a/Cargo.toml b/Cargo.toml
index 877fbde79e..7fa7546b85 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,11 @@
 [package]
 name = "solana"
 description = "High Performance Blockchain"
+<<<<<<< HEAD
 version = "0.5.0-beta"
+=======
+version = "0.5.0"
+>>>>>>> 3236be7877143563faf35255a599cb944603d0f3
 documentation = "https://docs.rs/solana"
 homepage = "http://solana.io/"
 repository = "https://github.com/solana-labs/solana"
@@ -68,3 +72,4 @@ libc = "^0.2.1"
 getopts = "^0.2"
 isatty = "0.1"
 futures = "0.1"
+rand = "0.4.2"
diff --git a/README.md b/README.md
index 729d99ac72..8a902bcd9a 100644
--- a/README.md
+++ b/README.md
@@ -102,6 +102,12 @@ $ source $HOME/.cargo/env
 $ rustup component add rustfmt-preview
 ```
 
+If your rustc version is lower than 1.25.0, please update it:
+
+```bash
+$ rustup update
+```
+
 Download the source code:
 
 ```bash
@@ -118,6 +124,18 @@ Run the test suite:
 cargo test
 ```
 
+Debugging
+---
+
+There are some useful debug messages in the code, you can enable them on a per-module and per-level
+basis with the normal RUST\_LOG environment variable. Run the testnode with this syntax:
+```bash
+$ RUST_LOG=solana::streamer=debug,solana::accountant_skel=info cat genesis.log | ./target/release/solana-testnode > transactions0.log
+```
+to see the debug and info sections for streamer and accountant\_skel respectively. Generally
+we are using debug for infrequent debug messages, trace for potentially frequent messages and
+info for performance-related logging.
+
 Benchmarking
 ---
 
@@ -133,6 +151,13 @@ Run the benchmarks:
 $ cargo +nightly bench --features="unstable"
 ```
 
+To run the benchmarks on Linux with GPU optimizations enabled:
+
+```bash
+$ wget https://solana-build-artifacts.s3.amazonaws.com/v0.5.0/libcuda_verify_ed25519.a
+$ cargo +nightly bench --features="unstable,cuda"
+```
+
 Code coverage
 ---
 
diff --git a/src/accountant.rs b/src/accountant.rs
index 683474efa7..a214aa4196 100644
--- a/src/accountant.rs
+++ b/src/accountant.rs
@@ -15,6 +15,7 @@ use signature::{KeyPair, PublicKey, Signature};
 use std::collections::hash_map::Entry::Occupied;
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::result;
+use std::sync::atomic::{AtomicIsize, Ordering};
 use std::sync::RwLock;
 use transaction::Transaction;
 
@@ -30,18 +31,18 @@ pub enum AccountingError {
 pub type Result<T> = result::Result<T, AccountingError>;
 
 /// Commit funds to the 'to' party.
-fn apply_payment(balances: &RwLock<HashMap<PublicKey, RwLock<i64>>>, payment: &Payment) {
+fn apply_payment(balances: &RwLock<HashMap<PublicKey, AtomicIsize>>, payment: &Payment) {
     if balances.read().unwrap().contains_key(&payment.to) {
         let bals = balances.read().unwrap();
-        *bals[&payment.to].write().unwrap() += payment.tokens;
+        bals[&payment.to].fetch_add(payment.tokens as isize, Ordering::Relaxed);
     } else {
         let mut bals = balances.write().unwrap();
-        bals.insert(payment.to, RwLock::new(payment.tokens));
+        bals.insert(payment.to, AtomicIsize::new(payment.tokens as isize));
     }
 }
 
 pub struct Accountant {
-    balances: RwLock<HashMap<PublicKey, RwLock<i64>>>,
+    balances: RwLock<HashMap<PublicKey, AtomicIsize>>,
     pending: RwLock<HashMap<Signature, Plan>>,
     last_ids: RwLock<VecDeque<(Hash, RwLock<HashSet<Signature>>)>>,
     time_sources: RwLock<HashSet<PublicKey>>,
@@ -73,6 +74,13 @@ impl Accountant {
         acc
     }
 
+    /// Return the last entry ID registered
+    pub fn last_id(&self) -> Hash {
+        let last_ids = self.last_ids.read().unwrap();
+        let last_item = last_ids.iter().last().expect("empty last_ids list");
+        last_item.0
+    }
+
     fn reserve_signature(signatures: &RwLock<HashSet<Signature>>, sig: &Signature) -> bool {
         if signatures.read().unwrap().contains(sig) {
             return false;
@@ -127,27 +135,37 @@ impl Accountant {
     /// funds and isn't a duplicate.
     pub fn process_verified_transaction_debits(&self, tr: &Transaction) -> Result<()> {
         let bals = self.balances.read().unwrap();
-
-        // Hold a write lock before the condition check, so that a debit can't occur
-        // between checking the balance and the withdraw.
         let option = bals.get(&tr.from);
+
         if option.is_none() {
             return Err(AccountingError::AccountNotFound);
         }
-        let mut bal = option.unwrap().write().unwrap();
 
         if !self.reserve_signature_with_last_id(&tr.sig, &tr.data.last_id) {
             return Err(AccountingError::InvalidTransferSignature);
         }
 
-        if *bal < tr.data.tokens {
-            self.forget_signature_with_last_id(&tr.sig, &tr.data.last_id);
-            return Err(AccountingError::InsufficientFunds);
+        loop {
+            let bal = option.unwrap();
+            let current = bal.load(Ordering::Relaxed) as i64;
+
+            if current < tr.data.tokens {
+                self.forget_signature_with_last_id(&tr.sig, &tr.data.last_id);
+                return Err(AccountingError::InsufficientFunds);
+            }
+
+            let result = bal.compare_exchange(
+                current as isize,
+                (current - tr.data.tokens) as isize,
+                Ordering::Relaxed,
+                Ordering::Relaxed,
+            );
+
+            match result {
+                Ok(_) => return Ok(()),
+                Err(_) => continue,
+            };
         }
-
-        *bal -= tr.data.tokens;
-
-        Ok(())
     }
 
     pub fn process_verified_transaction_credits(&self, tr: &Transaction) {
@@ -200,13 +218,18 @@ impl Accountant {
         (trs, rest)
     }
 
-    pub fn process_verified_events(&self, events: Vec<Event>) -> Result<()> {
+    pub fn process_verified_events(&self, events: Vec<Event>) -> Vec<Result<Event>> {
         let (trs, rest) = Self::partition_events(events);
-        self.process_verified_transactions(trs);
+        let mut results: Vec<_> = self.process_verified_transactions(trs)
+            .into_iter()
+            .map(|x| x.map(Event::Transaction))
+            .collect();
+
         for event in rest {
-            self.process_verified_event(&event)?;
+            results.push(self.process_verified_event(event));
         }
-        Ok(())
+
+        results
     }
 
     /// Process a Witness Signature that has already been verified.
@@ -260,12 +283,13 @@ impl Accountant {
     }
 
     /// Process an Transaction or Witness that has already been verified.
-    pub fn process_verified_event(&self, event: &Event) -> Result<()> {
-        match *event {
+    pub fn process_verified_event(&self, event: Event) -> Result<Event> {
+        match event {
             Event::Transaction(ref tr) => self.process_verified_transaction(tr),
             Event::Signature { from, tx_sig, .. } => self.process_verified_sig(from, tx_sig),
             Event::Timestamp { from, dt, .. } => self.process_verified_timestamp(from, dt),
-        }
+        }?;
+        Ok(event)
     }
 
     /// Create, sign, and process a Transaction from `keypair` to `to` of
@@ -300,7 +324,7 @@ impl Accountant {
 
     pub fn get_balance(&self, pubkey: &PublicKey) -> Option<i64> {
         let bals = self.balances.read().unwrap();
-        bals.get(pubkey).map(|x| *x.read().unwrap())
+        bals.get(pubkey).map(|x| x.load(Ordering::Relaxed) as i64)
     }
 }
 
@@ -316,6 +340,8 @@ mod tests {
         let alice = Mint::new(10_000);
         let bob_pubkey = KeyPair::new().pubkey();
         let acc = Accountant::new(&alice);
+        assert_eq!(acc.last_id(), alice.last_id());
+
         acc.transfer(1_000, &alice.keypair(), bob_pubkey, alice.last_id())
             .unwrap();
         assert_eq!(acc.get_balance(&bob_pubkey).unwrap(), 1_000);
diff --git a/src/accountant_skel.rs b/src/accountant_skel.rs
deleted file mode 100644
index 9712c6c031..0000000000
--- a/src/accountant_skel.rs
+++ /dev/null
@@ -1,810 +0,0 @@
-//! The `accountant_skel` module is a microservice that exposes the high-level
-//! Accountant API to the network. Its message encoding is currently
-//! in flux. Clients should use AccountantStub to interact with it.
-
-use accountant::Accountant;
-use bincode::{deserialize, serialize};
-use ecdsa;
-use entry::Entry;
-use event::Event;
-use hash::Hash;
-use historian::Historian;
-use packet;
-use packet::SharedPackets;
-use rayon::prelude::*;
-use recorder::Signal;
-use result::Result;
-use serde_json;
-use signature::PublicKey;
-use std::cmp::max;
-use std::collections::VecDeque;
-use std::io::Write;
-use std::net::{SocketAddr, UdpSocket};
-use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::mpsc::{channel, Receiver, Sender};
-use std::sync::{Arc, Mutex, RwLock};
-use std::thread::{spawn, JoinHandle};
-use std::time::Duration;
-use streamer;
-use transaction::Transaction;
-
-use subscribers;
-
-pub struct AccountantSkel<W: Write + Send + 'static> {
-    acc: Accountant,
-    last_id: Hash,
-    writer: W,
-    historian: Historian,
-    entry_info_subscribers: Vec<SocketAddr>,
-}
-
-#[cfg_attr(feature = "cargo-clippy", allow(large_enum_variant))]
-#[derive(Serialize, Deserialize, Debug, Clone)]
-pub enum Request {
-    Transaction(Transaction),
-    GetBalance { key: PublicKey },
-    GetLastId,
-    Subscribe { subscriptions: Vec<Subscription> },
-}
-
-#[derive(Serialize, Deserialize, Debug, Clone)]
-pub enum Subscription {
-    EntryInfo,
-}
-
-#[derive(Serialize, Deserialize, Debug, Clone)]
-pub struct EntryInfo {
-    pub id: Hash,
-    pub num_hashes: u64,
-    pub num_events: u64,
-}
-
-impl Request {
-    /// Verify the request is valid.
-    pub fn verify(&self) -> bool {
-        match *self {
-            Request::Transaction(ref tr) => tr.verify_plan(),
-            _ => true,
-        }
-    }
-}
-
-#[derive(Serialize, Deserialize, Debug)]
-pub enum Response {
-    Balance { key: PublicKey, val: Option<i64> },
-    EntryInfo(EntryInfo),
-    LastId { id: Hash },
-}
-
-impl<W: Write + Send + 'static> AccountantSkel<W> {
-    /// Create a new AccountantSkel that wraps the given Accountant.
-    pub fn new(acc: Accountant, last_id: Hash, writer: W, historian: Historian) -> Self {
-        AccountantSkel {
-            acc,
-            last_id,
-            writer,
-            historian,
-            entry_info_subscribers: vec![],
-        }
-    }
-
-    fn notify_entry_info_subscribers(&mut self, entry: &Entry) {
-        // TODO: No need to bind().
-        let socket = UdpSocket::bind("127.0.0.1:0").expect("bind");
-
-        for addr in &self.entry_info_subscribers {
-            let entry_info = EntryInfo {
-                id: entry.id,
-                num_hashes: entry.num_hashes,
-                num_events: entry.events.len() as u64,
-            };
-            let data = serialize(&Response::EntryInfo(entry_info)).expect("serialize EntryInfo");
-            let _res = socket.send_to(&data, addr);
-        }
-    }
-
-    /// Process any Entry items that have been published by the Historian.
-    pub fn sync(&mut self) -> Hash {
-        while let Ok(entry) = self.historian.receiver.try_recv() {
-            self.last_id = entry.id;
-            self.acc.register_entry_id(&self.last_id);
-            writeln!(self.writer, "{}", serde_json::to_string(&entry).unwrap()).unwrap();
-            self.notify_entry_info_subscribers(&entry);
-        }
-        self.last_id
-    }
-
-    /// Process Request items sent by clients.
-    pub fn process_request(
-        &mut self,
-        msg: Request,
-        rsp_addr: SocketAddr,
-    ) -> Option<(Response, SocketAddr)> {
-        match msg {
-            Request::GetBalance { key } => {
-                let val = self.acc.get_balance(&key);
-                Some((Response::Balance { key, val }, rsp_addr))
-            }
-            Request::GetLastId => Some((Response::LastId { id: self.sync() }, rsp_addr)),
-            Request::Transaction(_) => unreachable!(),
-            Request::Subscribe { subscriptions } => {
-                for subscription in subscriptions {
-                    match subscription {
-                        Subscription::EntryInfo => self.entry_info_subscribers.push(rsp_addr),
-                    }
-                }
-                None
-            }
-        }
-    }
-
-    fn recv_batch(recvr: &streamer::PacketReceiver) -> Result<Vec<SharedPackets>> {
-        let timer = Duration::new(1, 0);
-        let msgs = recvr.recv_timeout(timer)?;
-        trace!("got msgs");
-        let mut batch = vec![msgs];
-        while let Ok(more) = recvr.try_recv() {
-            trace!("got more msgs");
-            batch.push(more);
-        }
-        info!("batch len {}", batch.len());
-        Ok(batch)
-    }
-
-    fn verify_batch(batch: Vec<SharedPackets>) -> Vec<Vec<(SharedPackets, Vec<u8>)>> {
-        let chunk_size = max(1, (batch.len() + 3) / 4);
-        let batches: Vec<_> = batch.chunks(chunk_size).map(|x| x.to_vec()).collect();
-        batches
-            .into_par_iter()
-            .map(|batch| {
-                let r = ecdsa::ed25519_verify(&batch);
-                batch.into_iter().zip(r).collect()
-            })
-            .collect()
-    }
-
-    fn verifier(
-        recvr: &streamer::PacketReceiver,
-        sendr: &Sender<Vec<(SharedPackets, Vec<u8>)>>,
-    ) -> Result<()> {
-        let batch = Self::recv_batch(recvr)?;
-        let verified_batches = Self::verify_batch(batch);
-        for xs in verified_batches {
-            sendr.send(xs)?;
-        }
-        Ok(())
-    }
-
-    pub fn deserialize_packets(p: &packet::Packets) -> Vec<Option<(Request, SocketAddr)>> {
-        p.packets
-            .par_iter()
-            .map(|x| {
-                deserialize(&x.data[0..x.meta.size])
-                    .map(|req| (req, x.meta.addr()))
-                    .ok()
-            })
-            .collect()
-    }
-
-    /// Split Request list into verified transactions and the rest
-    fn partition_requests(
-        req_vers: Vec<(Request, SocketAddr, u8)>,
-    ) -> (Vec<Transaction>, Vec<(Request, SocketAddr)>) {
-        let mut trs = vec![];
-        let mut reqs = vec![];
-        for (msg, rsp_addr, verify) in req_vers {
-            match msg {
-                Request::Transaction(tr) => {
-                    if verify != 0 {
-                        trs.push(tr);
-                    }
-                }
-                _ => reqs.push((msg, rsp_addr)),
-            }
-        }
-        (trs, reqs)
-    }
-
-    fn process_packets(
-        &mut self,
-        req_vers: Vec<(Request, SocketAddr, u8)>,
-    ) -> Result<Vec<(Response, SocketAddr)>> {
-        let (trs, reqs) = Self::partition_requests(req_vers);
-
-        // Process the transactions in parallel and then log the successful ones.
-        for result in self.acc.process_verified_transactions(trs) {
-            if let Ok(tr) = result {
-                self.historian
-                    .sender
-                    .send(Signal::Event(Event::Transaction(tr)))?;
-            }
-        }
-
-        // Let validators know they should not attempt to process additional
-        // transactions in parallel.
-        self.historian.sender.send(Signal::Tick)?;
-
-        // Process the remaining requests serially.
-        let rsps = reqs.into_iter()
-            .filter_map(|(req, rsp_addr)| self.process_request(req, rsp_addr))
-            .collect();
-
-        Ok(rsps)
-    }
-
-    fn serialize_response(
-        resp: Response,
-        rsp_addr: SocketAddr,
-        blob_recycler: &packet::BlobRecycler,
-    ) -> Result<packet::SharedBlob> {
-        let blob = blob_recycler.allocate();
-        {
-            let mut b = blob.write().unwrap();
-            let v = serialize(&resp)?;
-            let len = v.len();
-            b.data[..len].copy_from_slice(&v);
-            b.meta.size = len;
-            b.meta.set_addr(&rsp_addr);
-        }
-        Ok(blob)
-    }
-
-    fn serialize_responses(
-        rsps: Vec<(Response, SocketAddr)>,
-        blob_recycler: &packet::BlobRecycler,
-    ) -> Result<VecDeque<packet::SharedBlob>> {
-        let mut blobs = VecDeque::new();
-        for (resp, rsp_addr) in rsps {
-            blobs.push_back(Self::serialize_response(resp, rsp_addr, blob_recycler)?);
-        }
-        Ok(blobs)
-    }
-
-    fn process(
-        obj: &Arc<Mutex<AccountantSkel<W>>>,
-        verified_receiver: &Receiver<Vec<(SharedPackets, Vec<u8>)>>,
-        blob_sender: &streamer::BlobSender,
-        packet_recycler: &packet::PacketRecycler,
-        blob_recycler: &packet::BlobRecycler,
-    ) -> Result<()> {
-        let timer = Duration::new(1, 0);
-        let mms = verified_receiver.recv_timeout(timer)?;
-        for (msgs, vers) in mms {
-            let reqs = Self::deserialize_packets(&msgs.read().unwrap());
-            let req_vers = reqs.into_iter()
-                .zip(vers)
-                .filter_map(|(req, ver)| req.map(|(msg, addr)| (msg, addr, ver)))
-                .filter(|x| x.0.verify())
-                .collect();
-            let rsps = obj.lock().unwrap().process_packets(req_vers)?;
-            let blobs = Self::serialize_responses(rsps, blob_recycler)?;
-            if !blobs.is_empty() {
-                //don't wake up the other side if there is nothing
-                blob_sender.send(blobs)?;
-            }
-            packet_recycler.recycle(msgs);
-
-            // Write new entries to the ledger and notify subscribers.
-            obj.lock().unwrap().sync();
-        }
-
-        Ok(())
-    }
-    /// Process verified blobs, already in order
-    /// Respond with a signed hash of the state
-    fn replicate_state(
-        obj: &Arc<Mutex<AccountantSkel<W>>>,
-        verified_receiver: &streamer::BlobReceiver,
-        blob_recycler: &packet::BlobRecycler,
-    ) -> Result<()> {
-        let timer = Duration::new(1, 0);
-        let blobs = verified_receiver.recv_timeout(timer)?;
-        for msgs in &blobs {
-            let blob = msgs.read().unwrap();
-            let entries: Vec<Entry> = deserialize(&blob.data()[..blob.meta.size]).unwrap();
-            for entry in entries {
-                obj.lock().unwrap().acc.register_entry_id(&entry.id);
-
-                obj.lock()
-                    .unwrap()
-                    .acc
-                    .process_verified_events(entry.events)?;
-            }
-            //TODO respond back to leader with hash of the state
-        }
-        for blob in blobs {
-            blob_recycler.recycle(blob);
-        }
-        Ok(())
-    }
-
-    /// Create a UDP microservice that forwards messages the given AccountantSkel.
-    /// This service is the network leader
-    /// Set `exit` to shutdown its threads.
-    pub fn serve(
-        obj: &Arc<Mutex<AccountantSkel<W>>>,
-        addr: &str,
-        exit: Arc<AtomicBool>,
-    ) -> Result<Vec<JoinHandle<()>>> {
-        let read = UdpSocket::bind(addr)?;
-        // make sure we are on the same interface
-        let mut local = read.local_addr()?;
-        local.set_port(0);
-        let write = UdpSocket::bind(local)?;
-
-        let packet_recycler = packet::PacketRecycler::default();
-        let blob_recycler = packet::BlobRecycler::default();
-        let (packet_sender, packet_receiver) = channel();
-        let t_receiver =
-            streamer::receiver(read, exit.clone(), packet_recycler.clone(), packet_sender)?;
-        let (blob_sender, blob_receiver) = channel();
-        let t_responder =
-            streamer::responder(write, exit.clone(), blob_recycler.clone(), blob_receiver);
-        let (verified_sender, verified_receiver) = channel();
-
-        let exit_ = exit.clone();
-        let t_verifier = spawn(move || loop {
-            let e = Self::verifier(&packet_receiver, &verified_sender);
-            if e.is_err() && exit_.load(Ordering::Relaxed) {
-                break;
-            }
-        });
-
-        let skel = obj.clone();
-        let t_server = spawn(move || loop {
-            let e = Self::process(
-                &skel,
-                &verified_receiver,
-                &blob_sender,
-                &packet_recycler,
-                &blob_recycler,
-            );
-            if e.is_err() {
-                // Assume this was a timeout, so sync any empty entries.
-                skel.lock().unwrap().sync();
-
-                if exit.load(Ordering::Relaxed) {
-                    break;
-                }
-            }
-        });
-        Ok(vec![t_receiver, t_responder, t_server, t_verifier])
-    }
-
-    /// This service receives messages from a leader in the network and processes the transactions
-    /// on the accountant state.
-    /// # Arguments
-    /// * `obj` - The accountant state.
-    /// * `rsubs` - The subscribers.
-    /// * `exit` - The exit signal.
-    /// # Remarks
-    /// The pipeline is constructed as follows:
-    /// 1. receive blobs from the network, these are out of order
-    /// 2. verify blobs, PoH, signatures (TODO)
-    /// 3. reconstruct contiguous window
-    ///     a. order the blobs
-    ///     b. use erasure coding to reconstruct missing blobs
-    ///     c. ask the network for missing blobs, if erasure coding is insufficient
-    ///     d. make sure that the blobs PoH sequences connect (TODO)
-    /// 4. process the transaction state machine
-    /// 5. respond with the hash of the state back to the leader
-    pub fn replicate(
-        obj: &Arc<Mutex<AccountantSkel<W>>>,
-        rsubs: subscribers::Subscribers,
-        exit: Arc<AtomicBool>,
-    ) -> Result<Vec<JoinHandle<()>>> {
-        let read = UdpSocket::bind(rsubs.me.addr)?;
-        // make sure we are on the same interface
-        let mut local = read.local_addr()?;
-        local.set_port(0);
-        let write = UdpSocket::bind(local)?;
-
-        let blob_recycler = packet::BlobRecycler::default();
-        let (blob_sender, blob_receiver) = channel();
-        let t_blob_receiver = streamer::blob_receiver(
-            exit.clone(),
-            blob_recycler.clone(),
-            read,
-            blob_sender.clone(),
-        )?;
-        let (window_sender, window_receiver) = channel();
-        let (retransmit_sender, retransmit_receiver) = channel();
-
-        let subs = Arc::new(RwLock::new(rsubs));
-        let t_retransmit = streamer::retransmitter(
-            write,
-            exit.clone(),
-            subs.clone(),
-            blob_recycler.clone(),
-            retransmit_receiver,
-        );
-        //TODO
-        //the packets coming out of blob_receiver need to be sent to the GPU and verified
-        //then sent to the window, which does the erasure coding reconstruction
-        let t_window = streamer::window(
-            exit.clone(),
-            subs,
-            blob_recycler.clone(),
-            blob_receiver,
-            window_sender,
-            retransmit_sender,
-        );
-
-        let skel = obj.clone();
-        let t_server = spawn(move || loop {
-            let e = Self::replicate_state(&skel, &window_receiver, &blob_recycler);
-            if e.is_err() && exit.load(Ordering::Relaxed) {
-                break;
-            }
-        });
-        Ok(vec![t_blob_receiver, t_retransmit, t_window, t_server])
-    }
-}
-
-#[cfg(test)]
-pub fn to_packets(r: &packet::PacketRecycler, reqs: Vec<Request>) -> Vec<SharedPackets> {
-    let mut out = vec![];
-    for rrs in reqs.chunks(packet::NUM_PACKETS) {
-        let p = r.allocate();
-        p.write()
-            .unwrap()
-            .packets
-            .resize(rrs.len(), Default::default());
-        for (i, o) in rrs.iter().zip(p.write().unwrap().packets.iter_mut()) {
-            let v = serialize(&i).expect("serialize request");
-            let len = v.len();
-            o.data[..len].copy_from_slice(&v);
-            o.meta.size = len;
-        }
-        out.push(p);
-    }
-    return out;
-}
-
-#[cfg(test)]
-mod tests {
-    use accountant_skel::{to_packets, Request};
-    use bincode::serialize;
-    use ecdsa;
-    use packet::{BlobRecycler, PacketRecycler, NUM_PACKETS};
-    use transaction::{memfind, test_tx};
-
-    use accountant::Accountant;
-    use accountant_skel::AccountantSkel;
-    use accountant_stub::AccountantStub;
-    use entry::Entry;
-    use futures::Future;
-    use historian::Historian;
-    use mint::Mint;
-    use plan::Plan;
-    use recorder::Signal;
-    use signature::{KeyPair, KeyPairUtil};
-    use std::io::sink;
-    use std::net::{SocketAddr, UdpSocket};
-    use std::sync::atomic::{AtomicBool, Ordering};
-    use std::sync::{Arc, Mutex};
-    use std::thread::sleep;
-    use std::time::Duration;
-    use transaction::Transaction;
-
-    use subscribers::{Node, Subscribers};
-    use streamer;
-    use std::sync::mpsc::channel;
-    use std::collections::VecDeque;
-    use hash::{hash, Hash};
-    use event::Event;
-    use entry;
-    use chrono::prelude::*;
-
-    #[test]
-    fn test_layout() {
-        let tr = test_tx();
-        let tx = serialize(&tr).unwrap();
-        let packet = serialize(&Request::Transaction(tr)).unwrap();
-        assert_matches!(memfind(&packet, &tx), Some(ecdsa::TX_OFFSET));
-        assert_matches!(memfind(&packet, &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]), None);
-    }
-    #[test]
-    fn test_to_packets() {
-        let tr = Request::Transaction(test_tx());
-        let re = PacketRecycler::default();
-        let rv = to_packets(&re, vec![tr.clone(); 1]);
-        assert_eq!(rv.len(), 1);
-        assert_eq!(rv[0].read().unwrap().packets.len(), 1);
-
-        let rv = to_packets(&re, vec![tr.clone(); NUM_PACKETS]);
-        assert_eq!(rv.len(), 1);
-        assert_eq!(rv[0].read().unwrap().packets.len(), NUM_PACKETS);
-
-        let rv = to_packets(&re, vec![tr.clone(); NUM_PACKETS + 1]);
-        assert_eq!(rv.len(), 2);
-        assert_eq!(rv[0].read().unwrap().packets.len(), NUM_PACKETS);
-        assert_eq!(rv[1].read().unwrap().packets.len(), 1);
-    }
-
-    #[test]
-    fn test_accounting_sequential_consistency() {
-        // In this attack we'll demonstrate that a verifier can interpret the ledger
-        // differently if either the server doesn't signal the ledger to add an
-        // Entry OR if the verifier tries to parallelize across multiple Entries.
-        let mint = Mint::new(2);
-        let acc = Accountant::new(&mint);
-        let rsp_addr: SocketAddr = "0.0.0.0:0".parse().expect("socket address");
-        let historian = Historian::new(&mint.last_id(), None);
-        let mut skel = AccountantSkel::new(acc, mint.last_id(), sink(), historian);
-
-        // Process a batch that includes a transaction that receives two tokens.
-        let alice = KeyPair::new();
-        let tr = Transaction::new(&mint.keypair(), alice.pubkey(), 2, mint.last_id());
-        let req_vers = vec![(Request::Transaction(tr), rsp_addr, 1_u8)];
-        assert!(skel.process_packets(req_vers).is_ok());
-
-        // Process a second batch that spends one of those tokens.
-        let tr = Transaction::new(&alice, mint.pubkey(), 1, mint.last_id());
-        let req_vers = vec![(Request::Transaction(tr), rsp_addr, 1_u8)];
-        assert!(skel.process_packets(req_vers).is_ok());
-
-        // Collect the ledger and feed it to a new accountant.
-        skel.historian.sender.send(Signal::Tick).unwrap();
-        drop(skel.historian.sender);
-        let entries: Vec<Entry> = skel.historian.receiver.iter().collect();
-
-        // Assert the user holds one token, not two. If the server only output one
-        // entry, then the second transaction will be rejected, because it drives
-        // the account balance below zero before the credit is added.
-        let acc = Accountant::new(&mint);
-        for entry in entries {
-            acc.process_verified_events(entry.events).unwrap();
-        }
-        assert_eq!(acc.get_balance(&alice.pubkey()), Some(1));
-    }
-
-    #[test]
-    fn test_accountant_bad_sig() {
-        let serve_port = 9002;
-        let send_port = 9003;
-        let addr = format!("127.0.0.1:{}", serve_port);
-        let send_addr = format!("127.0.0.1:{}", send_port);
-        let alice = Mint::new(10_000);
-        let acc = Accountant::new(&alice);
-        let bob_pubkey = KeyPair::new().pubkey();
-        let exit = Arc::new(AtomicBool::new(false));
-        let historian = Historian::new(&alice.last_id(), Some(30));
-        let acc = Arc::new(Mutex::new(AccountantSkel::new(
-            acc,
-            alice.last_id(),
-            sink(),
-            historian,
-        )));
-        let _threads = AccountantSkel::serve(&acc, &addr, exit.clone()).unwrap();
-        sleep(Duration::from_millis(300));
-
-        let socket = UdpSocket::bind(send_addr).unwrap();
-        socket.set_read_timeout(Some(Duration::new(5, 0))).unwrap();
-
-        let mut acc = AccountantStub::new(&addr, socket);
-        let last_id = acc.get_last_id().wait().unwrap();
-
-        let tr = Transaction::new(&alice.keypair(), bob_pubkey, 500, last_id);
-
-        let _sig = acc.transfer_signed(tr).unwrap();
-
-        let last_id = acc.get_last_id().wait().unwrap();
-
-        let mut tr2 = Transaction::new(&alice.keypair(), bob_pubkey, 501, last_id);
-        tr2.data.tokens = 502;
-        tr2.data.plan = Plan::new_payment(502, bob_pubkey);
-        let _sig = acc.transfer_signed(tr2).unwrap();
-
-        assert_eq!(acc.get_balance(&bob_pubkey).wait().unwrap(), 500);
-        exit.store(true, Ordering::Relaxed);
-    }
-
-    use std::sync::{Once, ONCE_INIT};
-    extern crate env_logger;
-
-    static INIT: Once = ONCE_INIT;
-
-    /// Setup function that is only run once, even if called multiple times.
-    fn setup() {
-        INIT.call_once(|| {
-            env_logger::init().unwrap();
-        });
-    }
-
-    #[test]
-    fn test_replicate() {
-        setup();
-        let leader_sock = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        let leader_addr = leader_sock.local_addr().unwrap();
-        let me_addr = "127.0.0.1:9010".parse().unwrap();
-        let target_peer_sock = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        let target_peer_addr = target_peer_sock.local_addr().unwrap();
-        let source_peer_sock = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        let exit = Arc::new(AtomicBool::new(false));
-
-        let node_me = Node::new([0, 0, 0, 0, 0, 0, 0, 1], 10, me_addr);
-        let node_subs = vec![Node::new([0, 0, 0, 0, 0, 0, 0, 2], 8, target_peer_addr); 1];
-        let node_leader = Node::new([0, 0, 0, 0, 0, 0, 0, 3], 20, leader_addr);
-        let subs = Subscribers::new(node_me, node_leader, &node_subs);
-
-        // setup some blob services to send blobs into the socket
-        // to simulate the source peer and get blobs out of the socket to
-        // simulate target peer
-        let recv_recycler = BlobRecycler::default();
-        let resp_recycler = BlobRecycler::default();
-        let (s_reader, r_reader) = channel();
-        let t_receiver = streamer::blob_receiver(
-            exit.clone(),
-            recv_recycler.clone(),
-            target_peer_sock,
-            s_reader,
-        ).unwrap();
-        let (s_responder, r_responder) = channel();
-        let t_responder = streamer::responder(
-            source_peer_sock,
-            exit.clone(),
-            resp_recycler.clone(),
-            r_responder,
-        );
-
-        let starting_balance = 10_000;
-        let alice = Mint::new(starting_balance);
-        let acc = Accountant::new(&alice);
-        let historian = Historian::new(&alice.last_id(), Some(30));
-        let acc = Arc::new(Mutex::new(AccountantSkel::new(
-            acc,
-            alice.last_id(),
-            sink(),
-            historian,
-        )));
-
-        let _threads = AccountantSkel::replicate(&acc, subs, exit.clone()).unwrap();
-
-        let mut alice_ref_balance = starting_balance;
-        let mut msgs = VecDeque::new();
-        let mut cur_hash = Hash::default();
-        let num_blobs = 10;
-        let transfer_amount = 501;
-        let bob_keypair = KeyPair::new();
-        for i in 0..num_blobs {
-            let b = resp_recycler.allocate();
-            let b_ = b.clone();
-            let mut w = b.write().unwrap();
-            w.set_index(i).unwrap();
-
-            let tr0 = Event::new_timestamp(&bob_keypair, Utc::now());
-            let entry0 = entry::create_entry(&cur_hash, i, vec![tr0]);
-            acc.lock().unwrap().acc.register_entry_id(&cur_hash);
-            cur_hash = hash(&cur_hash);
-
-            let tr1 = Transaction::new(
-                &alice.keypair(),
-                bob_keypair.pubkey(),
-                transfer_amount,
-                cur_hash,
-            );
-            acc.lock().unwrap().acc.register_entry_id(&cur_hash);
-            cur_hash = hash(&cur_hash);
-            let entry1 =
-                entry::create_entry(&cur_hash, i + num_blobs, vec![Event::Transaction(tr1)]);
-            acc.lock().unwrap().acc.register_entry_id(&cur_hash);
-            cur_hash = hash(&cur_hash);
-
-            alice_ref_balance -= transfer_amount;
-
-            let serialized_entry = serialize(&vec![entry0, entry1]).unwrap();
-
-            w.data_mut()[..serialized_entry.len()].copy_from_slice(&serialized_entry);
-            w.set_size(serialized_entry.len());
-            w.meta.set_addr(&me_addr);
-            drop(w);
-            msgs.push_back(b_);
-        }
-
-        // send the blobs into the socket
-        s_responder.send(msgs).expect("send");
-
-        // receive retransmitted messages
-        let timer = Duration::new(1, 0);
-        let mut msgs: Vec<_> = Vec::new();
-        while let Ok(msg) = r_reader.recv_timeout(timer) {
-            trace!("msg: {:?}", msg);
-            msgs.push(msg);
-        }
-
-        let alice_balance = acc.lock()
-            .unwrap()
-            .acc
-            .get_balance(&alice.keypair().pubkey())
-            .unwrap();
-        assert_eq!(alice_balance, alice_ref_balance);
-
-        let bob_balance = acc.lock()
-            .unwrap()
-            .acc
-            .get_balance(&bob_keypair.pubkey())
-            .unwrap();
-        assert_eq!(bob_balance, starting_balance - alice_ref_balance);
-
-        exit.store(true, Ordering::Relaxed);
-        t_receiver.join().expect("join");
-        t_responder.join().expect("join");
-    }
-
-}
-
-#[cfg(all(feature = "unstable", test))]
-mod bench {
-    extern crate test;
-    use self::test::Bencher;
-    use accountant::{Accountant, MAX_ENTRY_IDS};
-    use accountant_skel::*;
-    use bincode::serialize;
-    use hash::hash;
-    use mint::Mint;
-    use signature::{KeyPair, KeyPairUtil};
-    use std::collections::HashSet;
-    use std::io::sink;
-    use std::time::Instant;
-    use transaction::Transaction;
-
-    #[bench]
-    fn process_packets_bench(_bencher: &mut Bencher) {
-        let mint = Mint::new(100_000_000);
-        let acc = Accountant::new(&mint);
-        let rsp_addr: SocketAddr = "0.0.0.0:0".parse().expect("socket address");
-        // Create transactions between unrelated parties.
-        let txs = 100_000;
-        let last_ids: Mutex<HashSet<Hash>> = Mutex::new(HashSet::new());
-        let transactions: Vec<_> = (0..txs)
-            .into_par_iter()
-            .map(|i| {
-                // Seed the 'to' account and a cell for its signature.
-                let dummy_id = i % (MAX_ENTRY_IDS as i32);
-                let last_id = hash(&serialize(&dummy_id).unwrap()); // Semi-unique hash
-                {
-                    let mut last_ids = last_ids.lock().unwrap();
-                    if !last_ids.contains(&last_id) {
-                        last_ids.insert(last_id);
-                        acc.register_entry_id(&last_id);
-                    }
-                }
-
-                // Seed the 'from' account.
-                let rando0 = KeyPair::new();
-                let tr = Transaction::new(&mint.keypair(), rando0.pubkey(), 1_000, last_id);
-                acc.process_verified_transaction(&tr).unwrap();
-
-                let rando1 = KeyPair::new();
-                let tr = Transaction::new(&rando0, rando1.pubkey(), 2, last_id);
-                acc.process_verified_transaction(&tr).unwrap();
-
-                // Finally, return a transaction that's unique
-                Transaction::new(&rando0, rando1.pubkey(), 1, last_id)
-            })
-            .collect();
-
-        let req_vers = transactions
-            .into_iter()
-            .map(|tr| (Request::Transaction(tr), rsp_addr, 1_u8))
-            .collect();
-
-        let historian = Historian::new(&mint.last_id(), None);
-        let mut skel = AccountantSkel::new(acc, mint.last_id(), sink(), historian);
-
-        let now = Instant::now();
-        assert!(skel.process_packets(req_vers).is_ok());
-        let duration = now.elapsed();
-        let sec = duration.as_secs() as f64 + duration.subsec_nanos() as f64 / 1_000_000_000.0;
-        let tps = txs as f64 / sec;
-
-        // Ensure that all transactions were successfully logged.
-        drop(skel.historian.sender);
-        let entries: Vec<Entry> = skel.historian.receiver.iter().collect();
-        assert_eq!(entries.len(), 1);
-        assert_eq!(entries[0].events.len(), txs as usize);
-
-        println!("{} tps", tps);
-    }
-}
diff --git a/src/accountant_stub.rs b/src/accountant_stub.rs
deleted file mode 100644
index 2dd331da7b..0000000000
--- a/src/accountant_stub.rs
+++ /dev/null
@@ -1,201 +0,0 @@
-//! The `accountant_stub` module is a client-side object that interfaces with a server-side Accountant
-//! object via the network interface exposed by AccountantSkel. Client code should use
-//! this object instead of writing messages to the network directly. The binary
-//! encoding of its messages are unstable and may change in future releases.
-
-use accountant_skel::{Request, Response, Subscription};
-use bincode::{deserialize, serialize};
-use futures::future::{ok, FutureResult};
-use hash::Hash;
-use signature::{KeyPair, PublicKey, Signature};
-use std::collections::HashMap;
-use std::io;
-use std::net::UdpSocket;
-use transaction::Transaction;
-
-pub struct AccountantStub {
-    pub addr: String,
-    pub socket: UdpSocket,
-    last_id: Option<Hash>,
-    num_events: u64,
-    balances: HashMap<PublicKey, Option<i64>>,
-}
-
-impl AccountantStub {
-    /// Create a new AccountantStub that will interface with AccountantSkel
-    /// over `socket`. To receive responses, the caller must bind `socket`
-    /// to a public address before invoking AccountantStub methods.
-    pub fn new(addr: &str, socket: UdpSocket) -> Self {
-        let stub = AccountantStub {
-            addr: addr.to_string(),
-            socket,
-            last_id: None,
-            num_events: 0,
-            balances: HashMap::new(),
-        };
-        stub.init();
-        stub
-    }
-
-    pub fn init(&self) {
-        let subscriptions = vec![Subscription::EntryInfo];
-        let req = Request::Subscribe { subscriptions };
-        let data = serialize(&req).expect("serialize Subscribe");
-        let _res = self.socket.send_to(&data, &self.addr);
-    }
-
-    pub fn recv_response(&self) -> io::Result<Response> {
-        let mut buf = vec![0u8; 1024];
-        self.socket.recv_from(&mut buf)?;
-        let resp = deserialize(&buf).expect("deserialize balance");
-        Ok(resp)
-    }
-
-    pub fn process_response(&mut self, resp: Response) {
-        match resp {
-            Response::Balance { key, val } => {
-                self.balances.insert(key, val);
-            }
-            Response::LastId { id } => {
-                self.last_id = Some(id);
-            }
-            Response::EntryInfo(entry_info) => {
-                self.last_id = Some(entry_info.id);
-                self.num_events += entry_info.num_events;
-            }
-        }
-    }
-
-    /// Send a signed Transaction to the server for processing. This method
-    /// does not wait for a response.
-    pub fn transfer_signed(&self, tr: Transaction) -> io::Result<usize> {
-        let req = Request::Transaction(tr);
-        let data = serialize(&req).unwrap();
-        self.socket.send_to(&data, &self.addr)
-    }
-
-    /// Creates, signs, and processes a Transaction. Useful for writing unit-tests.
-    pub fn transfer(
-        &self,
-        n: i64,
-        keypair: &KeyPair,
-        to: PublicKey,
-        last_id: &Hash,
-    ) -> io::Result<Signature> {
-        let tr = Transaction::new(keypair, to, n, *last_id);
-        let sig = tr.sig;
-        self.transfer_signed(tr).map(|_| sig)
-    }
-
-    /// Request the balance of the user holding `pubkey`. This method blocks
-    /// until the server sends a response. If the response packet is dropped
-    /// by the network, this method will hang indefinitely.
-    pub fn get_balance(&mut self, pubkey: &PublicKey) -> FutureResult<i64, i64> {
-        let req = Request::GetBalance { key: *pubkey };
-        let data = serialize(&req).expect("serialize GetBalance");
-        self.socket
-            .send_to(&data, &self.addr)
-            .expect("buffer error");
-        let mut done = false;
-        while !done {
-            let resp = self.recv_response().expect("recv response");
-            if let &Response::Balance { ref key, .. } = &resp {
-                done = key == pubkey;
-            }
-            self.process_response(resp);
-        }
-        ok(self.balances[pubkey].unwrap())
-    }
-
-    /// Request the last Entry ID from the server. This method blocks
-    /// until the server sends a response. At the time of this writing,
-    /// it also has the side-effect of causing the server to log any
-    /// entries that have been published by the Historian.
-    pub fn get_last_id(&mut self) -> FutureResult<Hash, ()> {
-        let req = Request::GetLastId;
-        let data = serialize(&req).expect("serialize GetId");
-        self.socket
-            .send_to(&data, &self.addr)
-            .expect("buffer error");
-        let mut done = false;
-        while !done {
-            let resp = self.recv_response().expect("recv response");
-            if let &Response::LastId { .. } = &resp {
-                done = true;
-            }
-            self.process_response(resp);
-        }
-        ok(self.last_id.unwrap_or(Hash::default()))
-    }
-
-    /// Return the number of transactions the server processed since creating
-    /// this stub instance.
-    pub fn transaction_count(&mut self) -> u64 {
-        // Wait for at least one EntryInfo.
-        let mut done = false;
-        while !done {
-            let resp = self.recv_response().expect("recv response");
-            if let &Response::EntryInfo(_) = &resp {
-                done = true;
-            }
-            self.process_response(resp);
-        }
-
-        // Then take the rest.
-        self.socket.set_nonblocking(true).expect("set nonblocking");
-        loop {
-            match self.recv_response() {
-                Err(_) => break,
-                Ok(resp) => self.process_response(resp),
-            }
-        }
-        self.socket.set_nonblocking(false).expect("set blocking");
-        self.num_events
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use accountant::Accountant;
-    use accountant_skel::AccountantSkel;
-    use futures::Future;
-    use historian::Historian;
-    use mint::Mint;
-    use signature::{KeyPair, KeyPairUtil};
-    use std::io::sink;
-    use std::sync::atomic::{AtomicBool, Ordering};
-    use std::sync::{Arc, Mutex};
-    use std::thread::sleep;
-    use std::time::Duration;
-
-    // TODO: Figure out why this test sometimes hangs on TravisCI.
-    #[test]
-    fn test_accountant_stub() {
-        let addr = "127.0.0.1:9000";
-        let send_addr = "127.0.0.1:9001";
-        let alice = Mint::new(10_000);
-        let acc = Accountant::new(&alice);
-        let bob_pubkey = KeyPair::new().pubkey();
-        let exit = Arc::new(AtomicBool::new(false));
-        let historian = Historian::new(&alice.last_id(), Some(30));
-        let acc = Arc::new(Mutex::new(AccountantSkel::new(
-            acc,
-            alice.last_id(),
-            sink(),
-            historian,
-        )));
-        let _threads = AccountantSkel::serve(&acc, addr, exit.clone()).unwrap();
-        sleep(Duration::from_millis(300));
-
-        let socket = UdpSocket::bind(send_addr).unwrap();
-        socket.set_read_timeout(Some(Duration::new(5, 0))).unwrap();
-
-        let mut acc = AccountantStub::new(addr, socket);
-        let last_id = acc.get_last_id().wait().unwrap();
-        let _sig = acc.transfer(500, &alice.keypair(), bob_pubkey, &last_id)
-            .unwrap();
-        assert_eq!(acc.get_balance(&bob_pubkey).wait().unwrap(), 500);
-        exit.store(true, Ordering::Relaxed);
-    }
-}
diff --git a/src/bin/client-demo.rs b/src/bin/client-demo.rs
index 50f2e8a2ec..013e029300 100644
--- a/src/bin/client-demo.rs
+++ b/src/bin/client-demo.rs
@@ -10,14 +10,16 @@ use futures::Future;
 use getopts::Options;
 use isatty::stdin_isatty;
 use rayon::prelude::*;
-use solana::accountant_stub::AccountantStub;
 use solana::mint::MintDemo;
 use solana::signature::{KeyPair, KeyPairUtil};
+use solana::thin_client::ThinClient;
 use solana::transaction::Transaction;
 use std::env;
 use std::io::{stdin, Read};
-use std::net::UdpSocket;
+use std::net::{SocketAddr, UdpSocket};
 use std::process::exit;
+use std::thread::sleep;
+use std::time::Duration;
 use std::time::Instant;
 use untrusted::Input;
 
@@ -33,12 +35,12 @@ fn print_usage(program: &str, opts: Options) {
 fn main() {
     let mut threads = 4usize;
     let mut addr: String = "127.0.0.1:8000".to_string();
-    let mut send_addr: String = "127.0.0.1:8001".to_string();
+    let mut client_addr: String = "127.0.0.1:8010".to_string();
 
     let mut opts = Options::new();
     opts.optopt("s", "", "server address", "host:port");
     opts.optopt("c", "", "client address", "host:port");
-    opts.optopt("t", "", "number of threads", "4");
+    opts.optopt("t", "", "number of threads", &format!("{}", threads));
     opts.optflag("h", "help", "print help");
     let args: Vec<String> = env::args().collect();
     let matches = match opts.parse(&args[1..]) {
@@ -58,7 +60,7 @@ fn main() {
         addr = matches.opt_str("s").unwrap();
     }
     if matches.opt_present("c") {
-        send_addr = matches.opt_str("c").unwrap();
+        client_addr = matches.opt_str("c").unwrap();
     }
     if matches.opt_present("t") {
         threads = matches.opt_str("t").unwrap().parse().expect("integer");
@@ -82,11 +84,14 @@ fn main() {
         exit(1);
     });
 
-    let socket = UdpSocket::bind(&send_addr).unwrap();
-    let mut acc = AccountantStub::new(&addr, socket);
+    println!("Binding to {}", client_addr);
+    let socket = UdpSocket::bind(&client_addr).unwrap();
+    socket.set_read_timeout(Some(Duration::new(5, 0))).unwrap();
+    let mut acc = ThinClient::new(addr.parse().unwrap(), socket);
 
     println!("Get last ID...");
     let last_id = acc.get_last_id().wait().unwrap();
+    println!("Got last ID {:?}", last_id);
 
     println!("Creating keypairs...");
     let txs = demo.users.len() / 2;
@@ -102,7 +107,7 @@ fn main() {
         .into_par_iter()
         .map(|chunk| Transaction::new(&chunk[0], chunk[1].pubkey(), 1, last_id))
         .collect();
-    let duration = now.elapsed();
+    let mut duration = now.elapsed();
     let ns = duration.as_secs() * 1_000_000_000 + u64::from(duration.subsec_nanos());
     let bsps = txs as f64 / ns as f64;
     let nsps = ns as f64 / txs as f64;
@@ -113,31 +118,33 @@ fn main() {
     );
 
     let initial_tx_count = acc.transaction_count();
+    println!("initial count {}", initial_tx_count);
 
     println!("Transfering {} transactions in {} batches", txs, threads);
     let now = Instant::now();
     let sz = transactions.len() / threads;
     let chunks: Vec<_> = transactions.chunks(sz).collect();
     chunks.into_par_iter().for_each(|trs| {
-        println!("Transferring 1 unit {} times...", trs.len());
-        let send_addr = "0.0.0.0:0";
-        let socket = UdpSocket::bind(send_addr).unwrap();
-        let acc = AccountantStub::new(&addr, socket);
+        println!("Transferring 1 unit {} times... to", trs.len());
+        let mut client_addr: SocketAddr = client_addr.parse().unwrap();
+        client_addr.set_port(0);
+        let socket = UdpSocket::bind(client_addr).unwrap();
+        let acc = ThinClient::new(addr.parse().unwrap(), socket);
         for tr in trs {
             acc.transfer_signed(tr.clone()).unwrap();
         }
     });
 
-    println!("Waiting for half the transactions to complete...",);
-    let mut tx_count = acc.transaction_count();
-    while tx_count < transactions.len() as u64 / 2 {
+    println!("Waiting for transactions to complete...",);
+    let mut tx_count;
+    for _ in 0..10 {
         tx_count = acc.transaction_count();
+        duration = now.elapsed();
+        let txs = tx_count - initial_tx_count;
+        println!("Transactions processed {}", txs);
+        let ns = duration.as_secs() * 1_000_000_000 + u64::from(duration.subsec_nanos());
+        let tps = (txs * 1_000_000_000) as f64 / ns as f64;
+        println!("{} tps", tps);
+        sleep(Duration::new(1, 0));
     }
-    let txs = tx_count - initial_tx_count;
-    println!("Transactions processed {}", txs);
-
-    let duration = now.elapsed();
-    let ns = duration.as_secs() * 1_000_000_000 + u64::from(duration.subsec_nanos());
-    let tps = (txs * 1_000_000_000) as f64 / ns as f64;
-    println!("Done. {} tps", tps);
 }
diff --git a/src/bin/historian-demo.rs b/src/bin/historian-demo.rs
index 306b8ffbaa..134e7950f5 100644
--- a/src/bin/historian-demo.rs
+++ b/src/bin/historian-demo.rs
@@ -8,26 +8,27 @@ use solana::ledger::Block;
 use solana::recorder::Signal;
 use solana::signature::{KeyPair, KeyPairUtil};
 use solana::transaction::Transaction;
-use std::sync::mpsc::SendError;
+use std::sync::mpsc::{sync_channel, SendError, SyncSender};
 use std::thread::sleep;
 use std::time::Duration;
 
-fn create_ledger(hist: &Historian, seed: &Hash) -> Result<(), SendError<Signal>> {
+fn create_ledger(input: &SyncSender<Signal>, seed: &Hash) -> Result<(), SendError<Signal>> {
     sleep(Duration::from_millis(15));
     let keypair = KeyPair::new();
     let tr = Transaction::new(&keypair, keypair.pubkey(), 42, *seed);
     let signal0 = Signal::Event(Event::Transaction(tr));
-    hist.sender.send(signal0)?;
+    input.send(signal0)?;
     sleep(Duration::from_millis(10));
     Ok(())
 }
 
 fn main() {
+    let (input, event_receiver) = sync_channel(10);
     let seed = Hash::default();
-    let hist = Historian::new(&seed, Some(10));
-    create_ledger(&hist, &seed).expect("send error");
-    drop(hist.sender);
-    let entries: Vec<Entry> = hist.receiver.iter().collect();
+    let hist = Historian::new(event_receiver, &seed, Some(10));
+    create_ledger(&input, &seed).expect("send error");
+    drop(input);
+    let entries: Vec<Entry> = hist.output.lock().unwrap().iter().collect();
     for entry in &entries {
         println!("{:?}", entry);
     }
diff --git a/src/bin/testnode.rs b/src/bin/testnode.rs
index 8b6da2c1c8..cc4ad246ad 100644
--- a/src/bin/testnode.rs
+++ b/src/bin/testnode.rs
@@ -7,15 +7,19 @@ extern crate solana;
 use getopts::Options;
 use isatty::stdin_isatty;
 use solana::accountant::Accountant;
-use solana::accountant_skel::AccountantSkel;
+use solana::crdt::ReplicatedData;
 use solana::entry::Entry;
 use solana::event::Event;
 use solana::historian::Historian;
+use solana::signature::{KeyPair, KeyPairUtil};
+use solana::tpu::Tpu;
 use std::env;
 use std::io::{stdin, stdout, Read};
+use std::net::UdpSocket;
 use std::process::exit;
 use std::sync::atomic::AtomicBool;
-use std::sync::{Arc, Mutex};
+use std::sync::mpsc::sync_channel;
+use std::sync::Arc;
 
 fn print_usage(program: &str, opts: Options) {
     let mut brief = format!("Usage: cat <transaction.log> | {} [options]\n\n", program);
@@ -48,7 +52,10 @@ fn main() {
     if matches.opt_present("p") {
         port = matches.opt_str("p").unwrap().parse().expect("port");
     }
-    let addr = format!("0.0.0.0:{}", port);
+    let serve_addr = format!("0.0.0.0:{}", port);
+    let gossip_addr = format!("0.0.0.0:{}", port + 1);
+    let replicate_addr = format!("0.0.0.0:{}", port + 2);
+    let skinny_addr = format!("0.0.0.0:{}", port + 3);
 
     if stdin_isatty() {
         eprintln!("nothing found on stdin, expected a log file");
@@ -70,6 +77,8 @@ fn main() {
         })
     });
 
+    eprintln!("done parsing...");
+
     // The first item in the ledger is required to be an entry with zero num_hashes,
     // which implies its id can be used as the ledger's seed.
     let entry0 = entries.next().unwrap();
@@ -84,27 +93,55 @@ fn main() {
         None
     };
 
+    eprintln!("creating accountant...");
+
     let acc = Accountant::new_from_deposit(&deposit.unwrap());
     acc.register_entry_id(&entry0.id);
     acc.register_entry_id(&entry1.id);
 
+    eprintln!("processing entries...");
+
     let mut last_id = entry1.id;
     for entry in entries {
         last_id = entry.id;
-        acc.process_verified_events(entry.events).unwrap();
+        let results = acc.process_verified_events(entry.events);
+        for result in results {
+            if let Err(e) = result {
+                eprintln!("failed to process event {:?}", e);
+                exit(1);
+            }
+        }
         acc.register_entry_id(&last_id);
     }
 
-    let historian = Historian::new(&last_id, Some(1000));
+    eprintln!("creating networking stack...");
+
+    let (input, event_receiver) = sync_channel(10_000);
+    let historian = Historian::new(event_receiver, &last_id, Some(1000));
     let exit = Arc::new(AtomicBool::new(false));
-    let skel = Arc::new(Mutex::new(AccountantSkel::new(
-        acc,
-        last_id,
+    let tpu = Arc::new(Tpu::new(acc, input, historian));
+    let serve_sock = UdpSocket::bind(&serve_addr).unwrap();
+    let gossip_sock = UdpSocket::bind(&gossip_addr).unwrap();
+    let replicate_sock = UdpSocket::bind(&replicate_addr).unwrap();
+    let skinny_sock = UdpSocket::bind(&skinny_addr).unwrap();
+    let pubkey = KeyPair::new().pubkey();
+    let d = ReplicatedData::new(
+        pubkey,
+        gossip_sock.local_addr().unwrap(),
+        replicate_sock.local_addr().unwrap(),
+        serve_sock.local_addr().unwrap(),
+    );
+    eprintln!("starting server...");
+    let threads = Tpu::serve(
+        &tpu,
+        d,
+        serve_sock,
+        skinny_sock,
+        gossip_sock,
+        exit.clone(),
         stdout(),
-        historian,
-    )));
-    let threads = AccountantSkel::serve(&skel, &addr, exit.clone()).unwrap();
-    eprintln!("Ready. Listening on {}", addr);
+    ).unwrap();
+    eprintln!("Ready. Listening on {}", serve_addr);
     for t in threads {
         t.join().expect("join");
     }
diff --git a/src/crdt.rs b/src/crdt.rs
index b7742d5cd3..df01d89ec1 100644
--- a/src/crdt.rs
+++ b/src/crdt.rs
@@ -1,14 +1,24 @@
 //! The `crdt` module defines a data structure that is shared by all the nodes in the network over
-//! a gossip control plane.  The goal is to share small bits of of-chain information and detect and
+//! a gossip control plane.  The goal is to share small bits of off-chain information and detect and
 //! repair partitions.
 //!
 //! This CRDT only supports a very limited set of types.  A map of PublicKey -> Versioned Struct.
 //! The last version is always picked durring an update.
+//!
+//! The network is arranged in layers:
+//!
+//! * layer 0 - Leader.
+//! * layer 1 - As many nodes as we can fit
+//! * layer 2 - Everyone else, if layer 1 is `2^10`, layer 2 should be able to fit `2^20` number of nodes.
+//!
+//! Accountant needs to provide an interface for us to query the stake weight
 
 use bincode::{deserialize, serialize};
 use byteorder::{LittleEndian, ReadBytesExt};
 use hash::Hash;
-use result::Result;
+use packet::SharedBlob;
+use rayon::prelude::*;
+use result::{Error, Result};
 use ring::rand::{SecureRandom, SystemRandom};
 use signature::{PublicKey, Signature};
 use std::collections::HashMap;
@@ -22,16 +32,16 @@ use std::time::Duration;
 /// Structure to be replicated by the network
 #[derive(Serialize, Deserialize, Clone)]
 pub struct ReplicatedData {
-    id: PublicKey,
+    pub id: PublicKey,
     sig: Signature,
     /// should always be increasing
     version: u64,
     /// address to connect to for gossip
-    gossip_addr: SocketAddr,
+    pub gossip_addr: SocketAddr,
     /// address to connect to for replication
-    replicate_addr: SocketAddr,
+    pub replicate_addr: SocketAddr,
     /// address to connect to when this node is leader
-    lead_addr: SocketAddr,
+    pub serve_addr: SocketAddr,
     /// current leader identity
     current_leader_id: PublicKey,
     /// last verified hash that was submitted to the leader
@@ -41,15 +51,19 @@ pub struct ReplicatedData {
 }
 
 impl ReplicatedData {
-    pub fn new(id: PublicKey, gossip_addr: SocketAddr) -> ReplicatedData {
-        let daddr = "0.0.0.0:0".parse().unwrap();
+    pub fn new(
+        id: PublicKey,
+        gossip_addr: SocketAddr,
+        replicate_addr: SocketAddr,
+        serve_addr: SocketAddr,
+    ) -> ReplicatedData {
         ReplicatedData {
             id,
             sig: Signature::default(),
             version: 0,
             gossip_addr,
-            replicate_addr: daddr,
-            lead_addr: daddr,
+            replicate_addr,
+            serve_addr,
             current_leader_id: PublicKey::default(),
             last_verified_hash: Hash::default(),
             last_verified_count: 0,
@@ -77,8 +91,8 @@ pub struct Crdt {
     local: HashMap<PublicKey, u64>,
     /// The value of the remote update index that i have last seen
     /// This Node will ask external nodes for updates since the value in this list
-    remote: HashMap<PublicKey, u64>,
-    update_index: u64,
+    pub remote: HashMap<PublicKey, u64>,
+    pub update_index: u64,
     me: PublicKey,
     timeout: Duration,
 }
@@ -109,23 +123,141 @@ impl Crdt {
         g.table.insert(me.id, me);
         g
     }
-    pub fn import(&mut self, v: &ReplicatedData) {
-        // TODO check that last_verified types are always increasing
-        // TODO probably an error or attack
-        if self.me != v.id {
-            self.insert(v);
-        }
+    pub fn my_data(&self) -> &ReplicatedData {
+        &self.table[&self.me]
     }
-    pub fn insert(&mut self, v: &ReplicatedData) {
+    pub fn leader_data(&self) -> &ReplicatedData {
+        &self.table[&self.table[&self.me].current_leader_id]
+    }
+
+    pub fn set_leader(&mut self, key: PublicKey) -> () {
+        let mut me = self.my_data().clone();
+        me.current_leader_id = key;
+        me.version += 1;
+        self.insert(me);
+    }
+
+    pub fn insert(&mut self, v: ReplicatedData) {
+        // TODO check that last_verified types are always increasing
         if self.table.get(&v.id).is_none() || (v.version > self.table[&v.id].version) {
+            //somehow we signed a message for our own identity with a higher version that
+            // we have stored ourselves
+            trace!("me: {:?}", self.me[0]);
+            trace!("v.id: {:?}", v.id[0]);
             trace!("insert! {}", v.version);
             self.update_index += 1;
-            let _ = self.table.insert(v.id, v.clone());
+            let _ = self.table.insert(v.id.clone(), v.clone());
             let _ = self.local.insert(v.id, self.update_index);
         } else {
-            trace!("INSERT FAILED {}", v.version);
+            trace!(
+                "INSERT FAILED new.version: {} me.version: {}",
+                v.version,
+                self.table[&v.id].version
+            );
         }
     }
+
+    /// broadcast messages from the leader to layer 1 nodes
+    /// # Remarks
+    /// We need to avoid having obj locked while doing any io, such as the `send_to`
+    pub fn broadcast(
+        obj: &Arc<RwLock<Self>>,
+        blobs: &Vec<SharedBlob>,
+        s: &UdpSocket,
+        transmit_index: &mut u64,
+    ) -> Result<()> {
+        let (me, table): (ReplicatedData, Vec<ReplicatedData>) = {
+            // copy to avoid locking durring IO
+            let robj = obj.read().unwrap();
+            let cloned_table: Vec<ReplicatedData> = robj.table.values().cloned().collect();
+            (robj.table[&robj.me].clone(), cloned_table)
+        };
+        let daddr = "0.0.0.0:0".parse().unwrap();
+        let items: Vec<(usize, &ReplicatedData)> = table
+            .iter()
+            .filter(|v| {
+                if me.id == v.id {
+                    //filter myself
+                    false
+                } else if v.replicate_addr == daddr {
+                    //filter nodes that are not listening
+                    false
+                } else {
+                    true
+                }
+            })
+            .enumerate()
+            .collect();
+        let orders: Vec<_> = items.into_iter().cycle().zip(blobs.iter()).collect();
+        let errs: Vec<_> = orders
+            .into_par_iter()
+            .map(|((i, v), b)| {
+                // only leader should be broadcasting
+                assert!(me.current_leader_id != v.id);
+                let mut blob = b.write().unwrap();
+                blob.set_id(me.id).expect("set_id");
+                blob.set_index(*transmit_index + i as u64)
+                    .expect("set_index");
+                //TODO profile this, may need multiple sockets for par_iter
+                s.send_to(&blob.data[..blob.meta.size], &v.replicate_addr)
+            })
+            .collect();
+        for e in errs {
+            trace!("retransmit result {:?}", e);
+            match e {
+                Err(e) => return Err(Error::IO(e)),
+                _ => (),
+            }
+            *transmit_index += 1;
+        }
+        Ok(())
+    }
+
+    /// retransmit messages from the leader to layer 1 nodes
+    /// # Remarks
+    /// We need to avoid having obj locked while doing any io, such as the `send_to`
+    pub fn retransmit(obj: &Arc<RwLock<Self>>, blob: &SharedBlob, s: &UdpSocket) -> Result<()> {
+        let (me, table): (ReplicatedData, Vec<ReplicatedData>) = {
+            // copy to avoid locking durring IO
+            let s = obj.read().unwrap();
+            (s.table[&s.me].clone(), s.table.values().cloned().collect())
+        };
+        let rblob = blob.read().unwrap();
+        let daddr = "0.0.0.0:0".parse().unwrap();
+        let orders: Vec<_> = table
+            .iter()
+            .filter(|v| {
+                if me.id == v.id {
+                    false
+                } else if me.current_leader_id == v.id {
+                    trace!("skip retransmit to leader {:?}", v.id);
+                    false
+                } else if v.replicate_addr == daddr {
+                    trace!("skip nodes that are not listening {:?}", v.id);
+                    false
+                } else {
+                    true
+                }
+            })
+            .collect();
+        let errs: Vec<_> = orders
+            .par_iter()
+            .map(|v| {
+                trace!("retransmit blob to {}", v.replicate_addr);
+                //TODO profile this, may need multiple sockets for par_iter
+                s.send_to(&rblob.data[..rblob.meta.size], &v.replicate_addr)
+            })
+            .collect();
+        for e in errs {
+            trace!("retransmit result {:?}", e);
+            match e {
+                Err(e) => return Err(Error::IO(e)),
+                _ => (),
+            }
+        }
+        Ok(())
+    }
+
     fn random() -> u64 {
         let rnd = SystemRandom::new();
         let mut buf = [0u8; 8];
@@ -134,7 +266,7 @@ impl Crdt {
         rdr.read_u64::<LittleEndian>().unwrap()
     }
     fn get_updates_since(&self, v: u64) -> (PublicKey, u64, Vec<ReplicatedData>) {
-        trace!("get updates since {}", v);
+        //trace!("get updates since {}", v);
         let data = self.table
             .values()
             .filter(|x| self.local[&x.id] > v)
@@ -147,17 +279,21 @@ impl Crdt {
 
     /// Create a random gossip request
     /// # Returns
-    /// (A,B,C)
-    /// * A - Remote gossip address
-    /// * B - My gossip address
-    /// * C - Remote update index to request updates since
-    fn gossip_request(&self) -> (SocketAddr, Protocol) {
-        let n = (Self::random() as usize) % self.table.len();
-        trace!("random {:?} {}", &self.me[0..1], n);
+    /// (A,B)
+    /// * A - Address to send to
+    /// * B - RequestUpdates protocol message
+    fn gossip_request(&self) -> Result<(SocketAddr, Protocol)> {
+        if self.table.len() <= 1 {
+            return Err(Error::GeneralError);
+        }
+        let mut n = (Self::random() as usize) % self.table.len();
+        while self.table.values().nth(n).unwrap().id == self.me {
+            n = (Self::random() as usize) % self.table.len();
+        }
         let v = self.table.values().nth(n).unwrap().clone();
         let remote_update_index = *self.remote.get(&v.id).unwrap_or(&0);
         let req = Protocol::RequestUpdates(remote_update_index, self.table[&self.me].clone());
-        (v.gossip_addr, req)
+        Ok((v.gossip_addr, req))
     }
 
     /// At random pick a node and try to get updated changes from them
@@ -167,7 +303,7 @@ impl Crdt {
 
         // Lock the object only to do this operation and not for any longer
         // especially not when doing the `sock.send_to`
-        let (remote_gossip_addr, req) = obj.read().unwrap().gossip_request();
+        let (remote_gossip_addr, req) = obj.read().unwrap().gossip_request()?;
         let sock = UdpSocket::bind("0.0.0.0:0")?;
         // TODO this will get chatty, so we need to first ask for number of updates since
         // then only ask for specific data that we dont have
@@ -186,7 +322,7 @@ impl Crdt {
         // TODO we need to punish/spam resist here
         // sig verify the whole update and slash anyone who sends a bad update
         for v in data {
-            self.import(&v);
+            self.insert(v.clone());
         }
         *self.remote.entry(from).or_insert(update_index) = update_index;
     }
@@ -222,7 +358,7 @@ impl Crdt {
                 let rsp = serialize(&Protocol::ReceiveUpdates(from, ups, data))?;
                 trace!("send_to {}", addr);
                 //TODO verify reqdata belongs to sender
-                obj.write().unwrap().import(&reqdata);
+                obj.write().unwrap().insert(reqdata);
                 sock.send_to(&rsp, addr).unwrap();
                 trace!("send_to done!");
             }
@@ -251,6 +387,9 @@ impl Crdt {
 #[cfg(test)]
 mod test {
     use crdt::{Crdt, ReplicatedData};
+    use logger;
+    use packet::Blob;
+    use rayon::iter::*;
     use signature::KeyPair;
     use signature::KeyPairUtil;
     use std::net::UdpSocket;
@@ -259,6 +398,28 @@ mod test {
     use std::thread::{sleep, JoinHandle};
     use std::time::Duration;
 
+    fn test_node() -> (Crdt, UdpSocket, UdpSocket, UdpSocket) {
+        let gossip = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let replicate = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let serve = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let pubkey = KeyPair::new().pubkey();
+        let d = ReplicatedData::new(
+            pubkey,
+            gossip.local_addr().unwrap(),
+            replicate.local_addr().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+        let crdt = Crdt::new(d);
+        trace!(
+            "id: {} gossip: {} replicate: {} serve: {}",
+            crdt.my_data().id[0],
+            gossip.local_addr().unwrap(),
+            replicate.local_addr().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+        (crdt, gossip, replicate, serve)
+    }
+
     /// Test that the network converges.
     /// Run until every node in the network has a full ReplicatedData set.
     /// Check that nodes stop sending updates after all the ReplicatedData has been shared.
@@ -271,12 +432,9 @@ mod test {
         let exit = Arc::new(AtomicBool::new(false));
         let listen: Vec<_> = (0..num)
             .map(|_| {
-                let listener = UdpSocket::bind("0.0.0.0:0").unwrap();
-                let pubkey = KeyPair::new().pubkey();
-                let d = ReplicatedData::new(pubkey, listener.local_addr().unwrap());
-                let crdt = Crdt::new(d);
+                let (crdt, gossip, _, _) = test_node();
                 let c = Arc::new(RwLock::new(crdt));
-                let l = Crdt::listen(c.clone(), listener, exit.clone());
+                let l = Crdt::listen(c.clone(), gossip, exit.clone());
                 (c, l)
             })
             .collect();
@@ -332,7 +490,7 @@ mod test {
                 let yv = listen[y].0.read().unwrap();
                 let mut d = yv.table[&yv.me].clone();
                 d.version = 0;
-                xv.insert(&d);
+                xv.insert(d);
             }
         });
     }
@@ -349,7 +507,7 @@ mod test {
                 let yv = listen[y].0.read().unwrap();
                 let mut d = yv.table[&yv.me].clone();
                 d.version = 0;
-                xv.insert(&d);
+                xv.insert(d);
             }
         });
     }
@@ -357,16 +515,89 @@ mod test {
     /// Test that insert drops messages that are older
     #[test]
     fn insert_test() {
-        let mut d = ReplicatedData::new(KeyPair::new().pubkey(), "127.0.0.1:1234".parse().unwrap());
+        let mut d = ReplicatedData::new(
+            KeyPair::new().pubkey(),
+            "127.0.0.1:1234".parse().unwrap(),
+            "127.0.0.1:1235".parse().unwrap(),
+            "127.0.0.1:1236".parse().unwrap(),
+        );
         assert_eq!(d.version, 0);
         let mut crdt = Crdt::new(d.clone());
         assert_eq!(crdt.table[&d.id].version, 0);
         d.version = 2;
-        crdt.insert(&d);
+        crdt.insert(d.clone());
         assert_eq!(crdt.table[&d.id].version, 2);
         d.version = 1;
-        crdt.insert(&d);
+        crdt.insert(d.clone());
         assert_eq!(crdt.table[&d.id].version, 2);
     }
 
+    #[test]
+    pub fn test_crdt_retransmit() {
+        logger::setup();
+        trace!("c1:");
+        let (mut c1, s1, r1, e1) = test_node();
+        trace!("c2:");
+        let (mut c2, s2, r2, _) = test_node();
+        trace!("c3:");
+        let (mut c3, s3, r3, _) = test_node();
+        let c1_id = c1.my_data().id;
+        c1.set_leader(c1_id);
+
+        c2.insert(c1.my_data().clone());
+        c3.insert(c1.my_data().clone());
+
+        c2.set_leader(c1.my_data().id);
+        c3.set_leader(c1.my_data().id);
+
+        let exit = Arc::new(AtomicBool::new(false));
+
+        // Create listen threads
+        let a1 = Arc::new(RwLock::new(c1));
+        let t1 = Crdt::listen(a1.clone(), s1, exit.clone());
+
+        let a2 = Arc::new(RwLock::new(c2));
+        let t2 = Crdt::listen(a2.clone(), s2, exit.clone());
+
+        let a3 = Arc::new(RwLock::new(c3));
+        let t3 = Crdt::listen(a3.clone(), s3, exit.clone());
+
+        // Create gossip threads
+        let t1_gossip = Crdt::gossip(a1.clone(), exit.clone());
+        let t2_gossip = Crdt::gossip(a2.clone(), exit.clone());
+        let t3_gossip = Crdt::gossip(a3.clone(), exit.clone());
+
+        //wait to converge
+        trace!("waitng to converge:");
+        let mut done = false;
+        for _ in 0..10 {
+            done = a1.read().unwrap().table.len() == 3 && a2.read().unwrap().table.len() == 3
+                && a3.read().unwrap().table.len() == 3;
+            if done {
+                break;
+            }
+            sleep(Duration::new(1, 0));
+        }
+        assert!(done);
+        let mut b = Blob::default();
+        b.meta.size = 10;
+        Crdt::retransmit(&a1, &Arc::new(RwLock::new(b)), &e1).unwrap();
+        let res: Vec<_> = [r1, r2, r3]
+            .into_par_iter()
+            .map(|s| {
+                let mut b = Blob::default();
+                s.set_read_timeout(Some(Duration::new(1, 0))).unwrap();
+                let res = s.recv_from(&mut b.data);
+                res.is_err() //true if failed to receive the retransmit packet
+            })
+            .collect();
+        //true if failed receive the retransmit packet, r2, and r3 should succeed
+        //r1 was the sender, so it should fail to receive the packet
+        assert_eq!(res, [true, false, false]);
+        exit.store(true, Ordering::Relaxed);
+        let threads = vec![t1, t2, t3, t1_gossip, t2_gossip, t3_gossip];
+        for t in threads.into_iter() {
+            t.join().unwrap();
+        }
+    }
 }
diff --git a/src/ecdsa.rs b/src/ecdsa.rs
index c0a06646d0..4d7abbdbb4 100644
--- a/src/ecdsa.rs
+++ b/src/ecdsa.rs
@@ -130,11 +130,11 @@ pub fn ed25519_verify(batches: &Vec<SharedPackets>) -> Vec<Vec<u8>> {
 
 #[cfg(test)]
 mod tests {
-    use accountant_skel::Request;
     use bincode::serialize;
     use ecdsa;
     use packet::{Packet, Packets, SharedPackets};
     use std::sync::RwLock;
+    use tpu::Request;
     use transaction::test_tx;
     use transaction::Transaction;
 
diff --git a/src/erasure.rs b/src/erasure.rs
index b8480a73d7..12b4223bb9 100644
--- a/src/erasure.rs
+++ b/src/erasure.rs
@@ -153,7 +153,7 @@ pub fn decode_blocks(data: &mut [&mut [u8]], coding: &[&[u8]], erasures: &[i32])
 // Generate coding blocks in window from consumed to consumed+NUM_DATA
 pub fn generate_coding(
     re: &BlobRecycler,
-    window: &mut Vec<Option<SharedBlob>>,
+    window: &mut Vec<SharedBlob>,
     consumed: usize,
 ) -> Result<()> {
     let mut data_blobs = Vec::new();
@@ -179,7 +179,7 @@ pub fn generate_coding(
     let coding_end = consumed + NUM_CODED;
     for i in coding_start..coding_end {
         let n = i % window.len();
-        window[n] = Some(re.allocate());
+        window[n] = re.allocate();
         coding_blobs.push(window[n].clone().unwrap());
     }
     for b in &coding_blobs {
@@ -272,7 +272,6 @@ pub fn recover(
 mod test {
     use erasure;
     use packet::{BlobRecycler, SharedBlob, PACKET_DATA_SIZE};
-    extern crate env_logger;
 
     #[test]
     pub fn test_coding() {
diff --git a/src/historian.rs b/src/historian.rs
index 412027846f..7d2478bf15 100644
--- a/src/historian.rs
+++ b/src/historian.rs
@@ -4,25 +4,28 @@
 use entry::Entry;
 use hash::Hash;
 use recorder::{ExitReason, Recorder, Signal};
-use std::sync::mpsc::{sync_channel, Receiver, SyncSender};
+use std::sync::mpsc::{sync_channel, Receiver, SyncSender, TryRecvError};
+use std::sync::{Arc, Mutex};
 use std::thread::{spawn, JoinHandle};
 use std::time::Instant;
 
 pub struct Historian {
-    pub sender: SyncSender<Signal>,
-    pub receiver: Receiver<Entry>,
+    pub output: Arc<Mutex<Receiver<Entry>>>,
     pub thread_hdl: JoinHandle<ExitReason>,
 }
 
 impl Historian {
-    pub fn new(start_hash: &Hash, ms_per_tick: Option<u64>) -> Self {
-        let (sender, event_receiver) = sync_channel(10_000);
-        let (entry_sender, receiver) = sync_channel(10_000);
+    pub fn new(
+        event_receiver: Receiver<Signal>,
+        start_hash: &Hash,
+        ms_per_tick: Option<u64>,
+    ) -> Self {
+        let (entry_sender, output) = sync_channel(10_000);
         let thread_hdl =
             Historian::create_recorder(*start_hash, ms_per_tick, event_receiver, entry_sender);
+        let loutput = Arc::new(Mutex::new(output));
         Historian {
-            sender,
-            receiver,
+            output: loutput,
             thread_hdl,
         }
     }
@@ -48,6 +51,10 @@ impl Historian {
             }
         })
     }
+
+    pub fn receive(self: &Self) -> Result<Entry, TryRecvError> {
+        self.output.lock().unwrap().try_recv()
+    }
 }
 
 #[cfg(test)]
@@ -59,24 +66,25 @@ mod tests {
 
     #[test]
     fn test_historian() {
+        let (input, event_receiver) = sync_channel(10);
         let zero = Hash::default();
-        let hist = Historian::new(&zero, None);
+        let hist = Historian::new(event_receiver, &zero, None);
 
-        hist.sender.send(Signal::Tick).unwrap();
+        input.send(Signal::Tick).unwrap();
         sleep(Duration::new(0, 1_000_000));
-        hist.sender.send(Signal::Tick).unwrap();
+        input.send(Signal::Tick).unwrap();
         sleep(Duration::new(0, 1_000_000));
-        hist.sender.send(Signal::Tick).unwrap();
+        input.send(Signal::Tick).unwrap();
 
-        let entry0 = hist.receiver.recv().unwrap();
-        let entry1 = hist.receiver.recv().unwrap();
-        let entry2 = hist.receiver.recv().unwrap();
+        let entry0 = hist.output.lock().unwrap().recv().unwrap();
+        let entry1 = hist.output.lock().unwrap().recv().unwrap();
+        let entry2 = hist.output.lock().unwrap().recv().unwrap();
 
         assert_eq!(entry0.num_hashes, 0);
         assert_eq!(entry1.num_hashes, 0);
         assert_eq!(entry2.num_hashes, 0);
 
-        drop(hist.sender);
+        drop(input);
         assert_eq!(
             hist.thread_hdl.join().unwrap(),
             ExitReason::RecvDisconnected
@@ -87,10 +95,11 @@ mod tests {
 
     #[test]
     fn test_historian_closed_sender() {
+        let (input, event_receiver) = sync_channel(10);
         let zero = Hash::default();
-        let hist = Historian::new(&zero, None);
-        drop(hist.receiver);
-        hist.sender.send(Signal::Tick).unwrap();
+        let hist = Historian::new(event_receiver, &zero, None);
+        drop(hist.output);
+        input.send(Signal::Tick).unwrap();
         assert_eq!(
             hist.thread_hdl.join().unwrap(),
             ExitReason::SendDisconnected
@@ -99,12 +108,13 @@ mod tests {
 
     #[test]
     fn test_ticking_historian() {
+        let (input, event_receiver) = sync_channel(10);
         let zero = Hash::default();
-        let hist = Historian::new(&zero, Some(20));
+        let hist = Historian::new(event_receiver, &zero, Some(20));
         sleep(Duration::from_millis(300));
-        hist.sender.send(Signal::Tick).unwrap();
-        drop(hist.sender);
-        let entries: Vec<Entry> = hist.receiver.iter().collect();
+        input.send(Signal::Tick).unwrap();
+        drop(input);
+        let entries: Vec<Entry> = hist.output.lock().unwrap().iter().collect();
         assert!(entries.len() > 1);
 
         // Ensure the ID is not the seed.
diff --git a/src/lib.rs b/src/lib.rs
index 7a316f9ade..ab3fc2ff56 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,5 @@
 #![cfg_attr(feature = "unstable", feature(test))]
 pub mod accountant;
-pub mod accountant_skel;
-pub mod accountant_stub;
 pub mod crdt;
 pub mod ecdsa;
 pub mod entry;
@@ -11,6 +9,7 @@ pub mod event;
 pub mod hash;
 pub mod historian;
 pub mod ledger;
+pub mod logger;
 pub mod mint;
 pub mod packet;
 pub mod plan;
@@ -18,7 +17,9 @@ pub mod recorder;
 pub mod result;
 pub mod signature;
 pub mod streamer;
-pub mod subscribers;
+pub mod thin_client;
+pub mod timing;
+pub mod tpu;
 pub mod transaction;
 extern crate bincode;
 extern crate byteorder;
@@ -41,3 +42,5 @@ extern crate futures;
 #[cfg(test)]
 #[macro_use]
 extern crate matches;
+
+extern crate rand;
diff --git a/src/logger.rs b/src/logger.rs
new file mode 100644
index 0000000000..88bcc911bf
--- /dev/null
+++ b/src/logger.rs
@@ -0,0 +1,11 @@
+use std::sync::{Once, ONCE_INIT};
+extern crate env_logger;
+
+static INIT: Once = ONCE_INIT;
+
+/// Setup function that is only run once, even if called multiple times.
+pub fn setup() {
+    INIT.call_once(|| {
+        let _ = env_logger::init();
+    });
+}
diff --git a/src/packet.rs b/src/packet.rs
index d97b261e9f..713a166f68 100644
--- a/src/packet.rs
+++ b/src/packet.rs
@@ -1,12 +1,14 @@
 //! The `packet` module defines data structures and methods to pull data from the network.
+use bincode::{deserialize, serialize};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use result::{Error, Result};
+use signature::PublicKey;
 use std::collections::VecDeque;
 use std::fmt;
 use std::io;
+use std::mem::size_of;
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, UdpSocket};
 use std::sync::{Arc, Mutex, RwLock};
-use std::mem::size_of;
 
 pub type SharedPackets = Arc<RwLock<Packets>>;
 pub type SharedBlob = Arc<RwLock<Blob>>;
@@ -14,7 +16,8 @@ pub type PacketRecycler = Recycler<Packets>;
 pub type BlobRecycler = Recycler<Blob>;
 
 pub const NUM_PACKETS: usize = 1024 * 8;
-const BLOB_SIZE: usize = 64 * 1024;
+pub const BLOB_SIZE: usize = 64 * 1024;
+pub const BLOB_DATA_SIZE: usize = BLOB_SIZE - BLOB_ID_END;
 pub const PACKET_DATA_SIZE: usize = 256;
 pub const NUM_BLOBS: usize = (NUM_PACKETS * PACKET_DATA_SIZE) / BLOB_SIZE;
 
@@ -176,13 +179,14 @@ impl Packets {
         socket.set_nonblocking(false)?;
         for p in &mut self.packets {
             p.meta.size = 0;
+            trace!("receiving");
             match socket.recv_from(&mut p.data) {
                 Err(_) if i > 0 => {
-                    trace!("got {:?} messages", i);
+                    debug!("got {:?} messages", i);
                     break;
                 }
                 Err(e) => {
-                    info!("recv_from err {:?}", e);
+                    trace!("recv_from err {:?}", e);
                     return Err(Error::IO(e));
                 }
                 Ok((nrecv, from)) => {
@@ -200,6 +204,7 @@ impl Packets {
     pub fn recv_from(&mut self, socket: &UdpSocket) -> Result<()> {
         let sz = self.run_read_from(socket)?;
         self.packets.resize(sz, Packet::default());
+        debug!("recv_from: {}", sz);
         Ok(())
     }
     pub fn send_to(&self, socket: &UdpSocket) -> Result<()> {
@@ -211,28 +216,41 @@ impl Packets {
     }
 }
 
-const BLOB_INDEX_SIZE: usize = size_of::<u64>();
+const BLOB_INDEX_END: usize = size_of::<u64>();
+const BLOB_ID_END: usize = BLOB_INDEX_END + size_of::<usize>() + size_of::<PublicKey>();
 
 impl Blob {
     pub fn get_index(&self) -> Result<u64> {
-        let mut rdr = io::Cursor::new(&self.data[0..BLOB_INDEX_SIZE]);
+        let mut rdr = io::Cursor::new(&self.data[0..BLOB_INDEX_END]);
         let r = rdr.read_u64::<LittleEndian>()?;
         Ok(r)
     }
     pub fn set_index(&mut self, ix: u64) -> Result<()> {
         let mut wtr = vec![];
         wtr.write_u64::<LittleEndian>(ix)?;
-        self.data[..BLOB_INDEX_SIZE].clone_from_slice(&wtr);
+        self.data[..BLOB_INDEX_END].clone_from_slice(&wtr);
         Ok(())
     }
+
+    pub fn get_id(&self) -> Result<PublicKey> {
+        let e = deserialize(&self.data[BLOB_INDEX_END..BLOB_ID_END])?;
+        Ok(e)
+    }
+
+    pub fn set_id(&mut self, id: PublicKey) -> Result<()> {
+        let wtr = serialize(&id)?;
+        self.data[BLOB_INDEX_END..BLOB_ID_END].clone_from_slice(&wtr);
+        Ok(())
+    }
+
     pub fn data(&self) -> &[u8] {
-        &self.data[BLOB_INDEX_SIZE..]
+        &self.data[BLOB_ID_END..]
     }
     pub fn data_mut(&mut self) -> &mut [u8] {
-        &mut self.data[BLOB_INDEX_SIZE..]
+        &mut self.data[BLOB_ID_END..]
     }
     pub fn set_size(&mut self, size: usize) {
-        self.meta.size = size + BLOB_INDEX_SIZE;
+        self.meta.size = size + BLOB_ID_END;
     }
     pub fn recv_from(re: &BlobRecycler, socket: &UdpSocket) -> Result<VecDeque<SharedBlob>> {
         let mut v = VecDeque::new();
diff --git a/src/recorder.rs b/src/recorder.rs
index faf0759357..68a8cf8dae 100644
--- a/src/recorder.rs
+++ b/src/recorder.rs
@@ -8,6 +8,7 @@
 use entry::{create_entry_mut, Entry};
 use event::Event;
 use hash::{hash, Hash};
+use packet::BLOB_DATA_SIZE;
 use std::mem;
 use std::sync::mpsc::{Receiver, SyncSender, TryRecvError};
 use std::time::{Duration, Instant};
@@ -79,6 +80,13 @@ impl Recorder {
                     }
                     Signal::Event(event) => {
                         self.events.push(event);
+
+                        // Record an entry early if we anticipate its serialized size will
+                        // be larger than 64kb. At the time of this writing, we assume each
+                        // event will be well under 256 bytes.
+                        if self.events.len() >= BLOB_DATA_SIZE / 256 {
+                            self.record_entry()?;
+                        }
                     }
                 },
                 Err(TryRecvError::Empty) => return Ok(()),
@@ -87,3 +95,34 @@ impl Recorder {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use bincode::serialize;
+    use signature::{KeyPair, KeyPairUtil};
+    use std::sync::mpsc::sync_channel;
+    use transaction::Transaction;
+
+    #[test]
+    fn test_sub64k_entry_size() {
+        let (signal_sender, signal_receiver) = sync_channel(500);
+        let (entry_sender, entry_receiver) = sync_channel(10);
+        let zero = Hash::default();
+        let mut recorder = Recorder::new(signal_receiver, entry_sender, zero);
+        let alice_keypair = KeyPair::new();
+        let bob_pubkey = KeyPair::new().pubkey();
+        for _ in 0..256 {
+            let tx = Transaction::new(&alice_keypair, bob_pubkey, 1, zero);
+            let event = Event::Transaction(tx);
+            signal_sender.send(Signal::Event(event)).unwrap();
+        }
+
+        recorder.process_events(Instant::now(), None).unwrap();
+
+        drop(recorder.sender);
+        let entries: Vec<_> = entry_receiver.iter().collect();
+        assert_eq!(entries.len(), 1);
+        assert!(serialize(&entries[0]).unwrap().len() <= 65_536);
+    }
+}
diff --git a/src/result.rs b/src/result.rs
index 01872dfbe1..d2cb485add 100644
--- a/src/result.rs
+++ b/src/result.rs
@@ -1,10 +1,10 @@
 //! The `result` module exposes a Result type that propagates one of many different Error types.
 
+use accountant;
 use bincode;
 use serde_json;
 use std;
 use std::any::Any;
-use accountant;
 
 #[derive(Debug)]
 pub enum Error {
@@ -18,6 +18,7 @@ pub enum Error {
     AccountingError(accountant::AccountingError),
     SendError,
     Services,
+    GeneralError,
 }
 
 pub type Result<T> = std::result::Result<T, Error>;
diff --git a/src/streamer.rs b/src/streamer.rs
index 43e6f2ac35..808eea1e76 100644
--- a/src/streamer.rs
+++ b/src/streamer.rs
@@ -1,4 +1,7 @@
 //! The `streamer` module defines a set of services for effecently pulling data from udp sockets.
+use crdt::Crdt;
+#[cfg(feature = "erasure")]
+use erasure;
 use packet::{Blob, BlobRecycler, PacketRecycler, SharedBlob, SharedPackets, NUM_BLOBS};
 use result::Result;
 use std::collections::VecDeque;
@@ -8,7 +11,6 @@ use std::sync::mpsc;
 use std::sync::{Arc, RwLock};
 use std::thread::{spawn, JoinHandle};
 use std::time::Duration;
-use subscribers::Subscribers;
 
 pub type PacketReceiver = mpsc::Receiver<SharedPackets>;
 pub type PacketSender = mpsc::Sender<SharedPackets>;
@@ -99,17 +101,14 @@ pub fn blob_receiver(
         if exit.load(Ordering::Relaxed) {
             break;
         }
-        let ret = recv_blobs(&recycler, &sock, &s);
-        if ret.is_err() {
-            break;
-        }
+        let _ = recv_blobs(&recycler, &sock, &s);
     });
     Ok(t)
 }
 
 fn recv_window(
     window: &mut Vec<Option<SharedBlob>>,
-    subs: &Arc<RwLock<Subscribers>>,
+    crdt: &Arc<RwLock<Crdt>>,
     recycler: &BlobRecycler,
     consumed: &mut usize,
     r: &BlobReceiver,
@@ -118,24 +117,25 @@ fn recv_window(
 ) -> Result<()> {
     let timer = Duration::new(1, 0);
     let mut dq = r.recv_timeout(timer)?;
+    let leader_id = crdt.read().unwrap().leader_data().id;
     while let Ok(mut nq) = r.try_recv() {
         dq.append(&mut nq)
     }
     {
         //retransmit all leader blocks
         let mut retransmitq = VecDeque::new();
-        let rsubs = subs.read().unwrap();
         for b in &dq {
             let p = b.read().unwrap();
             //TODO this check isn't safe against adverserial packets
             //we need to maintain a sequence window
             trace!(
-                "idx: {} addr: {:?} leader: {:?}",
+                "idx: {} addr: {:?} id: {:?} leader: {:?}",
                 p.get_index().unwrap(),
+                p.get_id().unwrap(),
                 p.meta.addr(),
-                rsubs.leader.addr
+                leader_id
             );
-            if p.meta.addr() == rsubs.leader.addr {
+            if p.get_id().unwrap() == leader_id {
                 //TODO
                 //need to copy the retransmited blob
                 //otherwise we get into races with which thread
@@ -195,7 +195,7 @@ fn recv_window(
 
 pub fn window(
     exit: Arc<AtomicBool>,
-    subs: Arc<RwLock<Subscribers>>,
+    crdt: Arc<RwLock<Crdt>>,
     recycler: BlobRecycler,
     r: BlobReceiver,
     s: BlobSender,
@@ -210,7 +210,7 @@ pub fn window(
             }
             let _ = recv_window(
                 &mut window,
-                &subs,
+                &crdt,
                 &recycler,
                 &mut consumed,
                 &r,
@@ -221,8 +221,57 @@ pub fn window(
     })
 }
 
+fn broadcast(
+    crdt: &Arc<RwLock<Crdt>>,
+    recycler: &BlobRecycler,
+    r: &BlobReceiver,
+    sock: &UdpSocket,
+    transmit_index: &mut u64,
+) -> Result<()> {
+    let timer = Duration::new(1, 0);
+    let mut dq = r.recv_timeout(timer)?;
+    while let Ok(mut nq) = r.try_recv() {
+        dq.append(&mut nq);
+    }
+    let mut blobs = dq.into_iter().collect();
+    /// appends codes to the list of blobs allowing us to reconstruct the stream
+    #[cfg(feature = "erasure")]
+    erasure::generate_codes(blobs);
+    Crdt::broadcast(crdt, &blobs, &sock, transmit_index)?;
+    while let Some(b) = blobs.pop() {
+        recycler.recycle(b);
+    }
+    Ok(())
+}
+
+/// Service to broadcast messages from the leader to layer 1 nodes.
+/// See `crdt` for network layer definitions.
+/// # Arguments
+/// * `sock` - Socket to send from.
+/// * `exit` - Boolean to signal system exit.
+/// * `crdt` - CRDT structure
+/// * `recycler` - Blob recycler.
+/// * `r` - Receive channel for blobs to be retransmitted to all the layer 1 nodes.
+pub fn broadcaster(
+    sock: UdpSocket,
+    exit: Arc<AtomicBool>,
+    crdt: Arc<RwLock<Crdt>>,
+    recycler: BlobRecycler,
+    r: BlobReceiver,
+) -> JoinHandle<()> {
+    spawn(move || {
+        let mut transmit_index = 0;
+        loop {
+            if exit.load(Ordering::Relaxed) {
+                break;
+            }
+            let _ = broadcast(&crdt, &recycler, &r, &sock, &mut transmit_index);
+        }
+    })
+}
+
 fn retransmit(
-    subs: &Arc<RwLock<Subscribers>>,
+    crdt: &Arc<RwLock<Crdt>>,
     recycler: &BlobRecycler,
     r: &BlobReceiver,
     sock: &UdpSocket,
@@ -233,10 +282,8 @@ fn retransmit(
         dq.append(&mut nq);
     }
     {
-        let wsubs = subs.read().unwrap();
         for b in &dq {
-            let mut mb = b.write().unwrap();
-            wsubs.retransmit(&mut mb, sock)?;
+            Crdt::retransmit(&crdt, b, sock)?;
         }
     }
     while let Some(b) = dq.pop_front() {
@@ -246,26 +293,30 @@ fn retransmit(
 }
 
 /// Service to retransmit messages from the leader to layer 1 nodes.
-/// See `subscribers` for network layer definitions.
+/// See `crdt` for network layer definitions.
 /// # Arguments
 /// * `sock` - Socket to read from.  Read timeout is set to 1.
 /// * `exit` - Boolean to signal system exit.
-/// * `subs` - Shared Subscriber structure.  This structure needs to be updated and popualted by
-/// the accountant.
+/// * `crdt` - This structure needs to be updated and populated by the accountant and via gossip.
 /// * `recycler` - Blob recycler.
 /// * `r` - Receive channel for blobs to be retransmitted to all the layer 1 nodes.
 pub fn retransmitter(
     sock: UdpSocket,
     exit: Arc<AtomicBool>,
-    subs: Arc<RwLock<Subscribers>>,
+    crdt: Arc<RwLock<Crdt>>,
     recycler: BlobRecycler,
     r: BlobReceiver,
 ) -> JoinHandle<()> {
-    spawn(move || loop {
-        if exit.load(Ordering::Relaxed) {
-            break;
+    spawn(move || {
+        trace!("retransmitter started");
+        loop {
+            if exit.load(Ordering::Relaxed) {
+                break;
+            }
+            // TODO: handle this error
+            let _ = retransmit(&crdt, &recycler, &r, &sock);
         }
-        let _ = retransmit(&subs, &recycler, &r, &sock);
+        trace!("exiting retransmitter");
     })
 }
 
@@ -356,7 +407,7 @@ mod bench {
         let time = elapsed.as_secs() * 10000000000 + elapsed.subsec_nanos() as u64;
         let ftime = (time as f64) / 10000000000f64;
         let fcount = (end_val - start_val) as f64;
-        println!("performance: {:?}", fcount / ftime);
+        trace!("performance: {:?}", fcount / ftime);
         exit.store(true, Ordering::Relaxed);
         t_reader.join()?;
         t_producer1.join()?;
@@ -373,7 +424,11 @@ mod bench {
 
 #[cfg(test)]
 mod test {
+    use crdt::{Crdt, ReplicatedData};
+    use logger;
     use packet::{Blob, BlobRecycler, Packet, PacketRecycler, Packets, PACKET_DATA_SIZE};
+    use signature::KeyPair;
+    use signature::KeyPairUtil;
     use std::collections::VecDeque;
     use std::io;
     use std::io::Write;
@@ -381,17 +436,17 @@ mod test {
     use std::sync::atomic::{AtomicBool, Ordering};
     use std::sync::mpsc::channel;
     use std::sync::{Arc, RwLock};
+    use std::thread::sleep;
     use std::time::Duration;
-    use streamer::{blob_receiver, receiver, responder, retransmitter, window, BlobReceiver,
-                   PacketReceiver};
-    use subscribers::{Node, Subscribers};
+    use streamer::{blob_receiver, receiver, responder, retransmitter, window};
+    use streamer::{BlobReceiver, PacketReceiver};
 
     fn get_msgs(r: PacketReceiver, num: &mut usize) {
         for _t in 0..5 {
             let timer = Duration::new(1, 0);
             match r.recv_timeout(timer) {
                 Ok(m) => *num += m.read().unwrap().packets.len(),
-                e => println!("error {:?}", e),
+                e => info!("error {:?}", e),
             }
             if *num == 10 {
                 break;
@@ -445,7 +500,7 @@ mod test {
                     }
                     *num += m.len();
                 }
-                e => println!("error {:?}", e),
+                e => info!("error {:?}", e),
             }
             if *num == 10 {
                 break;
@@ -455,15 +510,23 @@ mod test {
 
     #[test]
     pub fn window_send_test() {
+        let pubkey_me = KeyPair::new().pubkey();
         let read = UdpSocket::bind("127.0.0.1:0").expect("bind");
         let addr = read.local_addr().unwrap();
         let send = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let serve = UdpSocket::bind("127.0.0.1:0").expect("bind");
         let exit = Arc::new(AtomicBool::new(false));
-        let subs = Arc::new(RwLock::new(Subscribers::new(
-            Node::default(),
-            Node::new([0; 8], 0, send.local_addr().unwrap()),
-            &[],
-        )));
+        let rep_data = ReplicatedData::new(
+            pubkey_me,
+            read.local_addr().unwrap(),
+            send.local_addr().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+        let mut crdt_me = Crdt::new(rep_data);
+        let me_id = crdt_me.my_data().id;
+        crdt_me.set_leader(me_id);
+        let subs = Arc::new(RwLock::new(crdt_me));
+
         let resp_recycler = BlobRecycler::default();
         let (s_reader, r_reader) = channel();
         let t_receiver =
@@ -487,6 +550,7 @@ mod test {
             let b_ = b.clone();
             let mut w = b.write().unwrap();
             w.set_index(i).unwrap();
+            w.set_id(me_id).unwrap();
             assert_eq!(i, w.get_index().unwrap());
             w.meta.size = PACKET_DATA_SIZE;
             w.meta.set_addr(&addr);
@@ -507,43 +571,102 @@ mod test {
         t_window.join().expect("join");
     }
 
+    fn test_node() -> (Arc<RwLock<Crdt>>, UdpSocket, UdpSocket, UdpSocket) {
+        let gossip = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let replicate = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let serve = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let pubkey = KeyPair::new().pubkey();
+        let d = ReplicatedData::new(
+            pubkey,
+            gossip.local_addr().unwrap(),
+            replicate.local_addr().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+        let crdt = Crdt::new(d);
+        trace!(
+            "id: {} gossip: {} replicate: {} serve: {}",
+            crdt.my_data().id[0],
+            gossip.local_addr().unwrap(),
+            replicate.local_addr().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+        (Arc::new(RwLock::new(crdt)), gossip, replicate, serve)
+    }
+
     #[test]
+    //retransmit from leader to replicate target
     pub fn retransmit() {
-        let read = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        let send = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        logger::setup();
+        trace!("retransmit test start");
         let exit = Arc::new(AtomicBool::new(false));
-        let subs = Arc::new(RwLock::new(Subscribers::new(
-            Node::default(),
-            Node::default(),
-            &[Node::new([0; 8], 1, read.local_addr().unwrap())],
-        )));
+        let (crdt_leader, sock_gossip_leader, _, sock_leader) = test_node();
+        let (crdt_target, sock_gossip_target, sock_replicate_target, _) = test_node();
+        let leader_data = crdt_leader.read().unwrap().my_data().clone();
+        crdt_leader.write().unwrap().insert(leader_data.clone());
+        crdt_leader.write().unwrap().set_leader(leader_data.id);
+        let t_crdt_leader_g = Crdt::gossip(crdt_leader.clone(), exit.clone());
+        let t_crdt_leader_l = Crdt::listen(crdt_leader.clone(), sock_gossip_leader, exit.clone());
+
+        crdt_target.write().unwrap().insert(leader_data.clone());
+        crdt_target.write().unwrap().set_leader(leader_data.id);
+        let t_crdt_target_g = Crdt::gossip(crdt_target.clone(), exit.clone());
+        let t_crdt_target_l = Crdt::listen(crdt_target.clone(), sock_gossip_target, exit.clone());
+        //leader retransmitter
         let (s_retransmit, r_retransmit) = channel();
         let blob_recycler = BlobRecycler::default();
-        let saddr = send.local_addr().unwrap();
+        let saddr = sock_leader.local_addr().unwrap();
         let t_retransmit = retransmitter(
-            send,
+            sock_leader,
             exit.clone(),
-            subs,
+            crdt_leader.clone(),
             blob_recycler.clone(),
             r_retransmit,
         );
+
+        //target receiver
+        let (s_blob_receiver, r_blob_receiver) = channel();
+        let t_receiver = blob_receiver(
+            exit.clone(),
+            blob_recycler.clone(),
+            sock_replicate_target,
+            s_blob_receiver,
+        ).unwrap();
+        for _ in 0..10 {
+            let done = crdt_target.read().unwrap().update_index == 2
+                && crdt_leader.read().unwrap().update_index == 2;
+            if done {
+                break;
+            }
+            let timer = Duration::new(1, 0);
+            sleep(timer);
+        }
+
+        //send the data through
         let mut bq = VecDeque::new();
         let b = blob_recycler.allocate();
         b.write().unwrap().meta.size = 10;
         bq.push_back(b);
         s_retransmit.send(bq).unwrap();
-        let (s_blob_receiver, r_blob_receiver) = channel();
-        let t_receiver =
-            blob_receiver(exit.clone(), blob_recycler.clone(), read, s_blob_receiver).unwrap();
-        let mut oq = r_blob_receiver.recv().unwrap();
+        let timer = Duration::new(5, 0);
+        trace!("Waiting for timeout");
+        let mut oq = r_blob_receiver.recv_timeout(timer).unwrap();
         assert_eq!(oq.len(), 1);
         let o = oq.pop_front().unwrap();
         let ro = o.read().unwrap();
         assert_eq!(ro.meta.size, 10);
         assert_eq!(ro.meta.addr(), saddr);
         exit.store(true, Ordering::Relaxed);
-        t_receiver.join().expect("join");
-        t_retransmit.join().expect("join");
+        let threads = vec![
+            t_receiver,
+            t_retransmit,
+            t_crdt_target_g,
+            t_crdt_target_l,
+            t_crdt_leader_g,
+            t_crdt_leader_l,
+        ];
+        for t in threads {
+            t.join().unwrap();
+        }
     }
 
 }
diff --git a/src/subscribers.rs b/src/subscribers.rs
deleted file mode 100644
index f0b271c439..0000000000
--- a/src/subscribers.rs
+++ /dev/null
@@ -1,149 +0,0 @@
-//! The `subscribers` module defines data structures to keep track of nodes on the network.
-//! The network is arranged in layers:
-//!
-//! * layer 0 - Leader.
-//! * layer 1 - As many nodes as we can fit to quickly get reliable `2/3+1` finality
-//! * layer 2 - Everyone else, if layer 1 is `2^10`, layer 2 should be able to fit `2^20` number of nodes.
-//!
-//! It's up to the external state machine to keep this updated.
-use packet::Blob;
-use rayon::prelude::*;
-use result::{Error, Result};
-use std::net::{SocketAddr, UdpSocket};
-
-use std::fmt;
-
-#[derive(Clone, PartialEq)]
-pub struct Node {
-    pub id: [u64; 8],
-    pub weight: u64,
-    pub addr: SocketAddr,
-}
-
-//sockaddr doesn't implement default
-impl Default for Node {
-    fn default() -> Node {
-        Node {
-            id: [0; 8],
-            weight: 0,
-            addr: "0.0.0.0:0".parse().unwrap(),
-        }
-    }
-}
-
-impl Node {
-    pub fn new(id: [u64; 8], weight: u64, addr: SocketAddr) -> Node {
-        Node { id, weight, addr }
-    }
-    fn key(&self) -> i64 {
-        (self.weight as i64).checked_neg().unwrap()
-    }
-}
-
-impl fmt::Debug for Node {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Node {{ weight: {} addr: {} }}", self.weight, self.addr)
-    }
-}
-
-pub struct Subscribers {
-    data: Vec<Node>,
-    pub me: Node,
-    pub leader: Node,
-}
-
-impl Subscribers {
-    pub fn new(me: Node, leader: Node, network: &[Node]) -> Subscribers {
-        let mut h = Subscribers {
-            data: vec![],
-            me: me.clone(),
-            leader: leader.clone(),
-        };
-        h.insert(&[me, leader]);
-        h.insert(network);
-        h
-    }
-
-    /// retransmit messages from the leader to layer 1 nodes
-    pub fn retransmit(&self, blob: &mut Blob, s: &UdpSocket) -> Result<()> {
-        let errs: Vec<_> = self.data
-            .par_iter()
-            .map(|i| {
-                if self.me == *i {
-                    return Ok(0);
-                }
-                if self.leader == *i {
-                    return Ok(0);
-                }
-                trace!("retransmit blob to {}", i.addr);
-                s.send_to(&blob.data[..blob.meta.size], &i.addr)
-            })
-            .collect();
-        for e in errs {
-            trace!("retransmit result {:?}", e);
-            match e {
-                Err(e) => return Err(Error::IO(e)),
-                _ => (),
-            }
-        }
-        Ok(())
-    }
-    pub fn insert(&mut self, ns: &[Node]) {
-        self.data.extend_from_slice(ns);
-        self.data.sort_by_key(Node::key);
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use packet::Blob;
-    use rayon::prelude::*;
-    use std::net::UdpSocket;
-    use std::time::Duration;
-    use subscribers::{Node, Subscribers};
-
-    #[test]
-    pub fn subscriber() {
-        let mut me = Node::default();
-        me.weight = 10;
-        let mut leader = Node::default();
-        leader.weight = 11;
-        let mut s = Subscribers::new(me, leader, &[]);
-        assert_eq!(s.data.len(), 2);
-        assert_eq!(s.data[0].weight, 11);
-        assert_eq!(s.data[1].weight, 10);
-        let mut n = Node::default();
-        n.weight = 12;
-        s.insert(&[n]);
-        assert_eq!(s.data.len(), 3);
-        assert_eq!(s.data[0].weight, 12);
-    }
-    #[test]
-    pub fn retransmit() {
-        let s1 = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        let s2 = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        let s3 = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        let n1 = Node::new([0; 8], 0, s1.local_addr().unwrap());
-        let n2 = Node::new([0; 8], 0, s2.local_addr().unwrap());
-        let mut s = Subscribers::new(n1.clone(), n2.clone(), &[]);
-        let n3 = Node::new([0; 8], 0, s3.local_addr().unwrap());
-        s.insert(&[n3]);
-        let mut b = Blob::default();
-        b.meta.size = 10;
-        let s4 = UdpSocket::bind("127.0.0.1:0").expect("bind");
-        s.retransmit(&mut b, &s4).unwrap();
-        let res: Vec<_> = [s1, s2, s3]
-            .into_par_iter()
-            .map(|s| {
-                let mut b = Blob::default();
-                s.set_read_timeout(Some(Duration::new(1, 0))).unwrap();
-                s.recv_from(&mut b.data).is_err()
-            })
-            .collect();
-        assert_eq!(res, [true, true, false]);
-        let mut n4 = Node::default();
-        n4.addr = "255.255.255.255:1".parse().unwrap();
-        s.insert(&[n4]);
-        assert!(s.retransmit(&mut b, &s4).is_err());
-    }
-}
diff --git a/src/thin_client.rs b/src/thin_client.rs
new file mode 100644
index 0000000000..3ae436ef8d
--- /dev/null
+++ b/src/thin_client.rs
@@ -0,0 +1,356 @@
+//! The `thin_client` module is a client-side object that interfaces with
+//! a server-side TPU.  Client code should use this object instead of writing
+//! messages to the network directly. The binary encoding of its messages are
+//! unstable and may change in future releases.
+
+use bincode::{deserialize, serialize};
+use futures::future::{ok, FutureResult};
+use hash::Hash;
+use signature::{KeyPair, PublicKey, Signature};
+use std::collections::HashMap;
+use std::io;
+use std::net::{SocketAddr, UdpSocket};
+use tpu::{Request, Response, Subscription};
+use transaction::Transaction;
+
+pub struct ThinClient {
+    pub addr: SocketAddr,
+    pub socket: UdpSocket,
+    last_id: Option<Hash>,
+    num_events: u64,
+    balances: HashMap<PublicKey, Option<i64>>,
+}
+
+impl ThinClient {
+    /// Create a new ThinClient that will interface with Tpu
+    /// over `socket`. To receive responses, the caller must bind `socket`
+    /// to a public address before invoking ThinClient methods.
+    pub fn new(addr: SocketAddr, socket: UdpSocket) -> Self {
+        let client = ThinClient {
+            addr: addr,
+            socket,
+            last_id: None,
+            num_events: 0,
+            balances: HashMap::new(),
+        };
+        client.init();
+        client
+    }
+
+    pub fn init(&self) {
+        let subscriptions = vec![Subscription::EntryInfo];
+        let req = Request::Subscribe { subscriptions };
+        let data = serialize(&req).expect("serialize Subscribe");
+        trace!("subscribing to {}", self.addr);
+        let _res = self.socket.send_to(&data, &self.addr);
+    }
+
+    pub fn recv_response(&self) -> io::Result<Response> {
+        let mut buf = vec![0u8; 1024];
+        info!("start recv_from");
+        self.socket.recv_from(&mut buf)?;
+        info!("end recv_from");
+        let resp = deserialize(&buf).expect("deserialize balance");
+        Ok(resp)
+    }
+
+    pub fn process_response(&mut self, resp: Response) {
+        match resp {
+            Response::Balance { key, val } => {
+                info!("Response balance {:?} {:?}", key, val);
+                self.balances.insert(key, val);
+            }
+            Response::EntryInfo(entry_info) => {
+                trace!("Response entry_info {:?}", entry_info.id);
+                self.last_id = Some(entry_info.id);
+                self.num_events += entry_info.num_events;
+            }
+        }
+    }
+
+    /// Send a signed Transaction to the server for processing. This method
+    /// does not wait for a response.
+    pub fn transfer_signed(&self, tr: Transaction) -> io::Result<usize> {
+        let req = Request::Transaction(tr);
+        let data = serialize(&req).unwrap();
+        self.socket.send_to(&data, &self.addr)
+    }
+
+    /// Creates, signs, and processes a Transaction. Useful for writing unit-tests.
+    pub fn transfer(
+        &self,
+        n: i64,
+        keypair: &KeyPair,
+        to: PublicKey,
+        last_id: &Hash,
+    ) -> io::Result<Signature> {
+        let tr = Transaction::new(keypair, to, n, *last_id);
+        let sig = tr.sig;
+        self.transfer_signed(tr).map(|_| sig)
+    }
+
+    /// Request the balance of the user holding `pubkey`. This method blocks
+    /// until the server sends a response. If the response packet is dropped
+    /// by the network, this method will hang indefinitely.
+    pub fn get_balance(&mut self, pubkey: &PublicKey) -> io::Result<i64> {
+        info!("get_balance");
+        let req = Request::GetBalance { key: *pubkey };
+        let data = serialize(&req).expect("serialize GetBalance");
+        self.socket
+            .send_to(&data, &self.addr)
+            .expect("buffer error");
+        let mut done = false;
+        while !done {
+            let resp = self.recv_response()?;
+            info!("recv_response {:?}", resp);
+            if let &Response::Balance { ref key, .. } = &resp {
+                done = key == pubkey;
+            }
+            self.process_response(resp);
+        }
+        self.balances[pubkey].ok_or(io::Error::new(io::ErrorKind::Other, "nokey"))
+    }
+
+    /// Request the last Entry ID from the server. This method blocks
+    /// until the server sends a response.
+    pub fn get_last_id(&mut self) -> FutureResult<Hash, ()> {
+        self.transaction_count();
+        ok(self.last_id.unwrap_or(Hash::default()))
+    }
+
+    /// Return the number of transactions the server processed since creating
+    /// this client instance.
+    pub fn transaction_count(&mut self) -> u64 {
+        // Wait for at least one EntryInfo.
+        let mut done = false;
+        while !done {
+            let resp = self.recv_response().expect("recv response");
+            if let &Response::EntryInfo(_) = &resp {
+                done = true;
+            }
+            self.process_response(resp);
+        }
+
+        // Then take the rest.
+        self.socket.set_nonblocking(true).expect("set nonblocking");
+        loop {
+            match self.recv_response() {
+                Err(_) => break,
+                Ok(resp) => self.process_response(resp),
+            }
+        }
+        self.socket.set_nonblocking(false).expect("set blocking");
+        self.num_events
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use accountant::Accountant;
+    use crdt::{Crdt, ReplicatedData};
+    use futures::Future;
+    use historian::Historian;
+    use logger;
+    use mint::Mint;
+    use signature::{KeyPair, KeyPairUtil};
+    use std::io::sink;
+    use std::sync::atomic::{AtomicBool, Ordering};
+    use std::sync::mpsc::sync_channel;
+    use std::sync::{Arc, RwLock};
+    use std::thread::sleep;
+    use std::time::Duration;
+    use std::time::Instant;
+    use tpu::Tpu;
+
+    // TODO: Figure out why this test sometimes hangs on TravisCI.
+    #[test]
+    fn test_thin_client() {
+        logger::setup();
+        let gossip = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let serve = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let skinny = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let addr = serve.local_addr().unwrap();
+        let pubkey = KeyPair::new().pubkey();
+        let d = ReplicatedData::new(
+            pubkey,
+            gossip.local_addr().unwrap(),
+            "0.0.0.0:0".parse().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+
+        let alice = Mint::new(10_000);
+        let acc = Accountant::new(&alice);
+        let bob_pubkey = KeyPair::new().pubkey();
+        let exit = Arc::new(AtomicBool::new(false));
+        let (input, event_receiver) = sync_channel(10);
+        let historian = Historian::new(event_receiver, &alice.last_id(), Some(30));
+        let acc = Arc::new(Tpu::new(acc, input, historian));
+        let threads = Tpu::serve(&acc, d, serve, skinny, gossip, exit.clone(), sink()).unwrap();
+        sleep(Duration::from_millis(300));
+
+        let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
+
+        let mut acc = ThinClient::new(addr, socket);
+        let last_id = acc.get_last_id().wait().unwrap();
+        let _sig = acc.transfer(500, &alice.keypair(), bob_pubkey, &last_id)
+            .unwrap();
+        let mut balance;
+        let now = Instant::now();
+        loop {
+            balance = acc.get_balance(&bob_pubkey);
+            if balance.is_ok() {
+                break;
+            }
+            if now.elapsed().as_secs() > 0 {
+                break;
+            }
+        }
+        assert_eq!(balance.unwrap(), 500);
+        exit.store(true, Ordering::Relaxed);
+        for t in threads {
+            t.join().unwrap();
+        }
+    }
+
+    fn test_node() -> (ReplicatedData, UdpSocket, UdpSocket, UdpSocket, UdpSocket) {
+        let gossip = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let serve = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let skinny = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let replicate = UdpSocket::bind("0.0.0.0:0").unwrap();
+        let pubkey = KeyPair::new().pubkey();
+        let leader = ReplicatedData::new(
+            pubkey,
+            gossip.local_addr().unwrap(),
+            replicate.local_addr().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+        (leader, gossip, serve, replicate, skinny)
+    }
+
+    #[test]
+    fn test_multi_node() {
+        logger::setup();
+        info!("test_multi_node");
+        let leader = test_node();
+        let replicant = test_node();
+        let alice = Mint::new(10_000);
+        let bob_pubkey = KeyPair::new().pubkey();
+        let exit = Arc::new(AtomicBool::new(false));
+
+        let leader_acc = {
+            let (input, event_receiver) = sync_channel(10);
+            let historian = Historian::new(event_receiver, &alice.last_id(), Some(30));
+            let acc = Accountant::new(&alice);
+            Arc::new(Tpu::new(acc, input, historian))
+        };
+
+        let replicant_acc = {
+            let (input, event_receiver) = sync_channel(10);
+            let historian = Historian::new(event_receiver, &alice.last_id(), Some(30));
+            let acc = Accountant::new(&alice);
+            Arc::new(Tpu::new(acc, input, historian))
+        };
+
+        let leader_threads = Tpu::serve(
+            &leader_acc,
+            leader.0.clone(),
+            leader.2,
+            leader.4,
+            leader.1,
+            exit.clone(),
+            sink(),
+        ).unwrap();
+        let replicant_threads = Tpu::replicate(
+            &replicant_acc,
+            replicant.0.clone(),
+            replicant.1,
+            replicant.2,
+            replicant.3,
+            leader.0.clone(),
+            exit.clone(),
+        ).unwrap();
+
+        //lets spy on the network
+        let (mut spy, spy_gossip, _, _, _) = test_node();
+        let daddr = "0.0.0.0:0".parse().unwrap();
+        spy.replicate_addr = daddr;
+        spy.serve_addr = daddr;
+        let mut spy_crdt = Crdt::new(spy);
+        spy_crdt.insert(leader.0.clone());
+        spy_crdt.set_leader(leader.0.id);
+
+        let spy_ref = Arc::new(RwLock::new(spy_crdt));
+        let t_spy_listen = Crdt::listen(spy_ref.clone(), spy_gossip, exit.clone());
+        let t_spy_gossip = Crdt::gossip(spy_ref.clone(), exit.clone());
+        //wait for the network to converge
+        for _ in 0..20 {
+            let ix = spy_ref.read().unwrap().update_index;
+            info!("my update index is {}", ix);
+            let len = spy_ref.read().unwrap().remote.values().len();
+            let mut done = false;
+            info!("remote len {}", len);
+            if len > 1 && ix > 2 {
+                done = true;
+                //check if everyones remote index is greater or equal to ours
+                let vs: Vec<u64> = spy_ref.read().unwrap().remote.values().cloned().collect();
+                for t in vs.into_iter() {
+                    info!("remote update index is {} vs {}", t, ix);
+                    if t < 3 {
+                        done = false;
+                    }
+                }
+            }
+            if done == true {
+                info!("converged!");
+                break;
+            }
+            sleep(Duration::new(1, 0));
+        }
+
+        //verify leader can do transfer
+        let leader_balance = {
+            let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
+            socket.set_read_timeout(Some(Duration::new(1, 0))).unwrap();
+
+            let mut acc = ThinClient::new(leader.0.serve_addr, socket);
+            info!("getting leader last_id");
+            let last_id = acc.get_last_id().wait().unwrap();
+            info!("executing leader transer");
+            let _sig = acc.transfer(500, &alice.keypair(), bob_pubkey, &last_id)
+                .unwrap();
+            info!("getting leader balance");
+            acc.get_balance(&bob_pubkey).unwrap()
+        };
+        assert_eq!(leader_balance, 500);
+        //verify replicant has the same balance
+        let mut replicant_balance = 0;
+        for _ in 0..10 {
+            let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
+            socket.set_read_timeout(Some(Duration::new(1, 0))).unwrap();
+
+            let mut acc = ThinClient::new(replicant.0.serve_addr, socket);
+            info!("getting replicant balance");
+            if let Ok(bal) = acc.get_balance(&bob_pubkey) {
+                replicant_balance = bal;
+            }
+            info!("replicant balance {}", replicant_balance);
+            if replicant_balance == leader_balance {
+                break;
+            }
+            sleep(Duration::new(1, 0));
+        }
+        assert_eq!(replicant_balance, leader_balance);
+
+        exit.store(true, Ordering::Relaxed);
+        for t in leader_threads {
+            t.join().unwrap();
+        }
+        for t in replicant_threads {
+            t.join().unwrap();
+        }
+        for t in vec![t_spy_listen, t_spy_gossip] {
+            t.join().unwrap();
+        }
+    }
+}
diff --git a/src/timing.rs b/src/timing.rs
new file mode 100644
index 0000000000..0d3c383839
--- /dev/null
+++ b/src/timing.rs
@@ -0,0 +1,15 @@
+use std::time::Duration;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+pub fn duration_as_ms(d: &Duration) -> u64 {
+    return (d.as_secs() * 1000) + (d.subsec_nanos() as u64 / 1_000_000);
+}
+
+pub fn duration_as_s(d: &Duration) -> f32 {
+    return d.as_secs() as f32 + (d.subsec_nanos() as f32 / 1_000_000_000.0);
+}
+
+pub fn timestamp() -> u64 {
+    let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
+    return duration_as_ms(&now);
+}
diff --git a/src/tpu.rs b/src/tpu.rs
new file mode 100644
index 0000000000..6da34e1332
--- /dev/null
+++ b/src/tpu.rs
@@ -0,0 +1,1198 @@
+//! The `tpu` module implements the Transaction Processing Unit, a
+//! 5-stage transaction processing pipeline in software.
+
+use accountant::Accountant;
+use bincode::{deserialize, serialize, serialize_into};
+use crdt::{Crdt, ReplicatedData};
+use ecdsa;
+use entry::Entry;
+use event::Event;
+use hash::Hash;
+use historian::Historian;
+use packet;
+use packet::{SharedBlob, SharedPackets, BLOB_SIZE};
+use rand::{thread_rng, Rng};
+use rayon::prelude::*;
+use recorder::Signal;
+use result::Result;
+use serde_json;
+use signature::PublicKey;
+use std::collections::VecDeque;
+use std::io::sink;
+use std::io::{Cursor, Write};
+use std::mem::size_of;
+use std::net::{SocketAddr, UdpSocket};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::mpsc::{channel, Receiver, Sender, SyncSender};
+use std::sync::{Arc, Mutex, RwLock};
+use std::thread::{spawn, JoinHandle};
+use std::time::Duration;
+use std::time::Instant;
+use streamer;
+use timing;
+use transaction::Transaction;
+
+pub struct Tpu {
+    acc: Mutex<Accountant>,
+    historian_input: Mutex<SyncSender<Signal>>,
+    historian: Historian,
+    entry_info_subscribers: Mutex<Vec<SocketAddr>>,
+}
+
+#[cfg_attr(feature = "cargo-clippy", allow(large_enum_variant))]
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub enum Request {
+    Transaction(Transaction),
+    GetBalance { key: PublicKey },
+    Subscribe { subscriptions: Vec<Subscription> },
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub enum Subscription {
+    EntryInfo,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub struct EntryInfo {
+    pub id: Hash,
+    pub num_hashes: u64,
+    pub num_events: u64,
+}
+
+impl Request {
+    /// Verify the request is valid.
+    pub fn verify(&self) -> bool {
+        match *self {
+            Request::Transaction(ref tr) => tr.verify_plan(),
+            _ => true,
+        }
+    }
+}
+
+type SharedTpu = Arc<Tpu>;
+
+#[derive(Serialize, Deserialize, Debug)]
+pub enum Response {
+    Balance { key: PublicKey, val: Option<i64> },
+    EntryInfo(EntryInfo),
+}
+
+impl Tpu {
+    /// Create a new Tpu that wraps the given Accountant.
+    pub fn new(acc: Accountant, historian_input: SyncSender<Signal>, historian: Historian) -> Self {
+        Tpu {
+            acc: Mutex::new(acc),
+            entry_info_subscribers: Mutex::new(vec![]),
+            historian_input: Mutex::new(historian_input),
+            historian,
+        }
+    }
+
+    fn notify_entry_info_subscribers(obj: &SharedTpu, entry: &Entry) {
+        // TODO: No need to bind().
+        let socket = UdpSocket::bind("0.0.0.0:0").expect("bind");
+
+        // copy subscribers to avoid taking lock while doing io
+        let addrs = obj.entry_info_subscribers.lock().unwrap().clone();
+        trace!("Sending to {} addrs", addrs.len());
+        for addr in addrs {
+            let entry_info = EntryInfo {
+                id: entry.id,
+                num_hashes: entry.num_hashes,
+                num_events: entry.events.len() as u64,
+            };
+            let data = serialize(&Response::EntryInfo(entry_info)).expect("serialize EntryInfo");
+            trace!("sending {} to {}", data.len(), addr);
+            //TODO dont do IO here, this needs to be on a separate channel
+            let res = socket.send_to(&data, addr);
+            if res.is_err() {
+                eprintln!("couldn't send response: {:?}", res);
+            }
+        }
+    }
+
+    fn update_entry<W: Write>(obj: &SharedTpu, writer: &Arc<Mutex<W>>, entry: &Entry) {
+        trace!("update_entry entry");
+        obj.acc.lock().unwrap().register_entry_id(&entry.id);
+        writeln!(
+            writer.lock().unwrap(),
+            "{}",
+            serde_json::to_string(&entry).unwrap()
+        ).unwrap();
+        Self::notify_entry_info_subscribers(obj, &entry);
+    }
+
+    fn receive_all<W: Write>(obj: &SharedTpu, writer: &Arc<Mutex<W>>) -> Result<Vec<Entry>> {
+        //TODO implement a serialize for channel that does this without allocations
+        let mut l = vec![];
+        let entry = obj.historian
+            .output
+            .lock()
+            .unwrap()
+            .recv_timeout(Duration::new(1, 0))?;
+        Self::update_entry(obj, writer, &entry);
+        l.push(entry);
+        while let Ok(entry) = obj.historian.receive() {
+            Self::update_entry(obj, writer, &entry);
+            l.push(entry);
+        }
+        Ok(l)
+    }
+
+    fn process_entry_list_into_blobs(
+        list: &Vec<Entry>,
+        blob_recycler: &packet::BlobRecycler,
+        q: &mut VecDeque<SharedBlob>,
+    ) {
+        let mut start = 0;
+        let mut end = 0;
+        while start < list.len() {
+            let mut total = 0;
+            for i in &list[start..] {
+                total += size_of::<Event>() * i.events.len();
+                total += size_of::<Entry>();
+                if total >= BLOB_SIZE {
+                    break;
+                }
+                end += 1;
+            }
+            // See that we made progress and a single
+            // vec of Events wasn't too big for a single packet
+            if end <= start {
+                // Trust the recorder to not package more than we can
+                // serialize
+                end += 1;
+            }
+
+            let b = blob_recycler.allocate();
+            let pos = {
+                let mut bd = b.write().unwrap();
+                let mut out = Cursor::new(bd.data_mut());
+                serialize_into(&mut out, &list[start..end]).expect("failed to serialize output");
+                out.position() as usize
+            };
+            assert!(pos < BLOB_SIZE);
+            b.write().unwrap().set_size(pos);
+            q.push_back(b);
+            start = end;
+        }
+    }
+
+    /// Process any Entry items that have been published by the Historian.
+    /// continuosly broadcast blobs of entries out
+    fn run_sync<W: Write>(
+        obj: SharedTpu,
+        broadcast: &streamer::BlobSender,
+        blob_recycler: &packet::BlobRecycler,
+        writer: &Arc<Mutex<W>>,
+    ) -> Result<()> {
+        let mut q = VecDeque::new();
+        let list = Self::receive_all(&obj, writer)?;
+        trace!("New blobs? {}", list.len());
+        Self::process_entry_list_into_blobs(&list, blob_recycler, &mut q);
+        if !q.is_empty() {
+            broadcast.send(q)?;
+        }
+        Ok(())
+    }
+
+    pub fn sync_service<W: Write + Send + 'static>(
+        obj: SharedTpu,
+        exit: Arc<AtomicBool>,
+        broadcast: streamer::BlobSender,
+        blob_recycler: packet::BlobRecycler,
+        writer: Arc<Mutex<W>>,
+    ) -> JoinHandle<()> {
+        spawn(move || loop {
+            let _ = Self::run_sync(obj.clone(), &broadcast, &blob_recycler, &writer);
+            if exit.load(Ordering::Relaxed) {
+                info!("sync_service exiting");
+                break;
+            }
+        })
+    }
+
+    fn process_thin_client_requests(_obj: SharedTpu, _socket: &UdpSocket) -> Result<()> {
+        Ok(())
+    }
+
+    fn thin_client_service(
+        obj: SharedTpu,
+        exit: Arc<AtomicBool>,
+        socket: UdpSocket,
+    ) -> JoinHandle<()> {
+        spawn(move || loop {
+            let _ = Self::process_thin_client_requests(obj.clone(), &socket);
+            if exit.load(Ordering::Relaxed) {
+                info!("sync_service exiting");
+                break;
+            }
+        })
+    }
+
+    /// Process any Entry items that have been published by the Historian.
+    /// continuosly broadcast blobs of entries out
+    fn run_sync_no_broadcast(obj: SharedTpu) -> Result<()> {
+        Self::receive_all(&obj, &Arc::new(Mutex::new(sink())))?;
+        Ok(())
+    }
+
+    pub fn sync_no_broadcast_service(obj: SharedTpu, exit: Arc<AtomicBool>) -> JoinHandle<()> {
+        spawn(move || loop {
+            let _ = Self::run_sync_no_broadcast(obj.clone());
+            if exit.load(Ordering::Relaxed) {
+                info!("sync_no_broadcast_service exiting");
+                break;
+            }
+        })
+    }
+
+    /// Process Request items sent by clients.
+    pub fn process_request(
+        &self,
+        msg: Request,
+        rsp_addr: SocketAddr,
+    ) -> Option<(Response, SocketAddr)> {
+        match msg {
+            Request::GetBalance { key } => {
+                let val = self.acc.lock().unwrap().get_balance(&key);
+                let rsp = (Response::Balance { key, val }, rsp_addr);
+                info!("Response::Balance {:?}", rsp);
+                Some(rsp)
+            }
+            Request::Transaction(_) => unreachable!(),
+            Request::Subscribe { subscriptions } => {
+                for subscription in subscriptions {
+                    match subscription {
+                        Subscription::EntryInfo => {
+                            self.entry_info_subscribers.lock().unwrap().push(rsp_addr)
+                        }
+                    }
+                }
+                None
+            }
+        }
+    }
+
+    fn recv_batch(recvr: &streamer::PacketReceiver) -> Result<(Vec<SharedPackets>, usize)> {
+        let timer = Duration::new(1, 0);
+        let msgs = recvr.recv_timeout(timer)?;
+        debug!("got msgs");
+        let mut len = msgs.read().unwrap().packets.len();
+        let mut batch = vec![msgs];
+        while let Ok(more) = recvr.try_recv() {
+            trace!("got more msgs");
+            len += more.read().unwrap().packets.len();
+            batch.push(more);
+
+            if len > 100_000 {
+                break;
+            }
+        }
+        debug!("batch len {}", batch.len());
+        Ok((batch, len))
+    }
+
+    fn verify_batch(
+        batch: Vec<SharedPackets>,
+        sendr: &Arc<Mutex<Sender<Vec<(SharedPackets, Vec<u8>)>>>>,
+    ) -> Result<()> {
+        let r = ecdsa::ed25519_verify(&batch);
+        let res = batch.into_iter().zip(r).collect();
+        sendr.lock().unwrap().send(res)?;
+        // TODO: fix error handling here?
+        Ok(())
+    }
+
+    fn verifier(
+        recvr: &Arc<Mutex<streamer::PacketReceiver>>,
+        sendr: &Arc<Mutex<Sender<Vec<(SharedPackets, Vec<u8>)>>>>,
+    ) -> Result<()> {
+        let (batch, len) = Self::recv_batch(&recvr.lock().unwrap())?;
+        let now = Instant::now();
+        let batch_len = batch.len();
+        let rand_id = thread_rng().gen_range(0, 100);
+        info!(
+            "@{:?} verifier: verifying: {} id: {}",
+            timing::timestamp(),
+            batch.len(),
+            rand_id
+        );
+
+        Self::verify_batch(batch, sendr).unwrap();
+
+        let total_time_ms = timing::duration_as_ms(&now.elapsed());
+        let total_time_s = timing::duration_as_s(&now.elapsed());
+        info!(
+            "@{:?} verifier: done. batches: {} total verify time: {:?} id: {} verified: {} v/s {}",
+            timing::timestamp(),
+            batch_len,
+            total_time_ms,
+            rand_id,
+            len,
+            (len as f32 / total_time_s)
+        );
+        Ok(())
+    }
+
+    pub fn deserialize_packets(p: &packet::Packets) -> Vec<Option<(Request, SocketAddr)>> {
+        p.packets
+            .par_iter()
+            .map(|x| {
+                deserialize(&x.data[0..x.meta.size])
+                    .map(|req| (req, x.meta.addr()))
+                    .ok()
+            })
+            .collect()
+    }
+
+    /// Split Request list into verified transactions and the rest
+    fn partition_requests(
+        req_vers: Vec<(Request, SocketAddr, u8)>,
+    ) -> (Vec<Event>, Vec<(Request, SocketAddr)>) {
+        let mut events = vec![];
+        let mut reqs = vec![];
+        for (msg, rsp_addr, verify) in req_vers {
+            match msg {
+                Request::Transaction(tr) => {
+                    if verify != 0 {
+                        events.push(Event::Transaction(tr));
+                    }
+                }
+                _ => reqs.push((msg, rsp_addr)),
+            }
+        }
+        (events, reqs)
+    }
+
+    /// Process the transactions in parallel and then log the successful ones.
+    fn process_events(&self, events: Vec<Event>) -> Result<()> {
+        for result in self.acc.lock().unwrap().process_verified_events(events) {
+            if let Ok(event) = result {
+                self.historian_input
+                    .lock()
+                    .unwrap()
+                    .send(Signal::Event(event))?;
+            }
+        }
+
+        // Let validators know they should not attempt to process additional
+        // transactions in parallel.
+        self.historian_input.lock().unwrap().send(Signal::Tick)?;
+        debug!("after historian_input");
+
+        Ok(())
+    }
+
+    fn process_requests(&self, reqs: Vec<(Request, SocketAddr)>) -> Vec<(Response, SocketAddr)> {
+        reqs.into_iter()
+            .filter_map(|(req, rsp_addr)| self.process_request(req, rsp_addr))
+            .collect()
+    }
+
+    fn serialize_response(
+        resp: Response,
+        rsp_addr: SocketAddr,
+        blob_recycler: &packet::BlobRecycler,
+    ) -> Result<packet::SharedBlob> {
+        let blob = blob_recycler.allocate();
+        {
+            let mut b = blob.write().unwrap();
+            let v = serialize(&resp)?;
+            let len = v.len();
+            b.data[..len].copy_from_slice(&v);
+            b.meta.size = len;
+            b.meta.set_addr(&rsp_addr);
+        }
+        Ok(blob)
+    }
+
+    fn serialize_responses(
+        rsps: Vec<(Response, SocketAddr)>,
+        blob_recycler: &packet::BlobRecycler,
+    ) -> Result<VecDeque<packet::SharedBlob>> {
+        let mut blobs = VecDeque::new();
+        for (resp, rsp_addr) in rsps {
+            blobs.push_back(Self::serialize_response(resp, rsp_addr, blob_recycler)?);
+        }
+        Ok(blobs)
+    }
+
+    fn process(
+        obj: &SharedTpu,
+        verified_receiver: &Receiver<Vec<(SharedPackets, Vec<u8>)>>,
+        responder_sender: &streamer::BlobSender,
+        packet_recycler: &packet::PacketRecycler,
+        blob_recycler: &packet::BlobRecycler,
+    ) -> Result<()> {
+        let timer = Duration::new(1, 0);
+        let recv_start = Instant::now();
+        let mms = verified_receiver.recv_timeout(timer)?;
+        let mut reqs_len = 0;
+        let mms_len = mms.len();
+        info!(
+            "@{:?} process start stalled for: {:?}ms batches: {}",
+            timing::timestamp(),
+            timing::duration_as_ms(&recv_start.elapsed()),
+            mms.len(),
+        );
+        let proc_start = Instant::now();
+        for (msgs, vers) in mms {
+            let reqs = Self::deserialize_packets(&msgs.read().unwrap());
+            reqs_len += reqs.len();
+            let req_vers = reqs.into_iter()
+                .zip(vers)
+                .filter_map(|(req, ver)| req.map(|(msg, addr)| (msg, addr, ver)))
+                .filter(|x| {
+                    let v = x.0.verify();
+                    v
+                })
+                .collect();
+
+            debug!("partitioning");
+            let (events, reqs) = Self::partition_requests(req_vers);
+            debug!("events: {} reqs: {}", events.len(), reqs.len());
+
+            debug!("process_events");
+            obj.process_events(events)?;
+            debug!("done process_events");
+
+            debug!("process_requests");
+            let rsps = obj.process_requests(reqs);
+            debug!("done process_requests");
+
+            let blobs = Self::serialize_responses(rsps, blob_recycler)?;
+            if !blobs.is_empty() {
+                info!("process: sending blobs: {}", blobs.len());
+                //don't wake up the other side if there is nothing
+                responder_sender.send(blobs)?;
+            }
+            packet_recycler.recycle(msgs);
+        }
+        let total_time_s = timing::duration_as_s(&proc_start.elapsed());
+        let total_time_ms = timing::duration_as_ms(&proc_start.elapsed());
+        info!(
+            "@{:?} done process batches: {} time: {:?}ms reqs: {} reqs/s: {}",
+            timing::timestamp(),
+            mms_len,
+            total_time_ms,
+            reqs_len,
+            (reqs_len as f32) / (total_time_s)
+        );
+        Ok(())
+    }
+    /// Process verified blobs, already in order
+    /// Respond with a signed hash of the state
+    fn replicate_state(
+        obj: &SharedTpu,
+        verified_receiver: &streamer::BlobReceiver,
+        blob_recycler: &packet::BlobRecycler,
+    ) -> Result<()> {
+        let timer = Duration::new(1, 0);
+        let blobs = verified_receiver.recv_timeout(timer)?;
+        trace!("replicating blobs {}", blobs.len());
+        for msgs in &blobs {
+            let blob = msgs.read().unwrap();
+            let entries: Vec<Entry> = deserialize(&blob.data()[..blob.meta.size]).unwrap();
+            let acc = obj.acc.lock().unwrap();
+            for entry in entries {
+                acc.register_entry_id(&entry.id);
+                for result in acc.process_verified_events(entry.events) {
+                    result?;
+                }
+            }
+            //TODO respond back to leader with hash of the state
+        }
+        for blob in blobs {
+            blob_recycler.recycle(blob);
+        }
+        Ok(())
+    }
+
+    /// Create a UDP microservice that forwards messages the given Tpu.
+    /// This service is the network leader
+    /// Set `exit` to shutdown its threads.
+    pub fn serve<W: Write + Send + 'static>(
+        obj: &SharedTpu,
+        me: ReplicatedData,
+        serve: UdpSocket,
+        skinny: UdpSocket,
+        gossip: UdpSocket,
+        exit: Arc<AtomicBool>,
+        writer: W,
+    ) -> Result<Vec<JoinHandle<()>>> {
+        let crdt = Arc::new(RwLock::new(Crdt::new(me)));
+        let t_gossip = Crdt::gossip(crdt.clone(), exit.clone());
+        let t_listen = Crdt::listen(crdt.clone(), gossip, exit.clone());
+
+        // make sure we are on the same interface
+        let mut local = serve.local_addr()?;
+        local.set_port(0);
+        let respond_socket = UdpSocket::bind(local.clone())?;
+
+        let packet_recycler = packet::PacketRecycler::default();
+        let blob_recycler = packet::BlobRecycler::default();
+        let (packet_sender, packet_receiver) = channel();
+        let t_receiver =
+            streamer::receiver(serve, exit.clone(), packet_recycler.clone(), packet_sender)?;
+        let (responder_sender, responder_receiver) = channel();
+        let t_responder = streamer::responder(
+            respond_socket,
+            exit.clone(),
+            blob_recycler.clone(),
+            responder_receiver,
+        );
+        let (verified_sender, verified_receiver) = channel();
+
+        let mut verify_threads = Vec::new();
+        let shared_verified_sender = Arc::new(Mutex::new(verified_sender));
+        let shared_packet_receiver = Arc::new(Mutex::new(packet_receiver));
+        for _ in 0..4 {
+            let exit_ = exit.clone();
+            let recv = shared_packet_receiver.clone();
+            let sender = shared_verified_sender.clone();
+            let thread = spawn(move || loop {
+                let e = Self::verifier(&recv, &sender);
+                if e.is_err() && exit_.load(Ordering::Relaxed) {
+                    break;
+                }
+            });
+            verify_threads.push(thread);
+        }
+
+        let (broadcast_sender, broadcast_receiver) = channel();
+
+        let broadcast_socket = UdpSocket::bind(local)?;
+        let t_broadcast = streamer::broadcaster(
+            broadcast_socket,
+            exit.clone(),
+            crdt.clone(),
+            blob_recycler.clone(),
+            broadcast_receiver,
+        );
+
+        let t_sync = Self::sync_service(
+            obj.clone(),
+            exit.clone(),
+            broadcast_sender,
+            blob_recycler.clone(),
+            Arc::new(Mutex::new(writer)),
+        );
+
+        let t_skinny = Self::thin_client_service(obj.clone(), exit.clone(), skinny);
+
+        let tpu = obj.clone();
+        let t_server = spawn(move || loop {
+            let e = Self::process(
+                &mut tpu.clone(),
+                &verified_receiver,
+                &responder_sender,
+                &packet_recycler,
+                &blob_recycler,
+            );
+            if e.is_err() {
+                if exit.load(Ordering::Relaxed) {
+                    break;
+                }
+            }
+        });
+
+        let mut threads = vec![
+            t_receiver,
+            t_responder,
+            t_server,
+            t_sync,
+            t_skinny,
+            t_gossip,
+            t_listen,
+            t_broadcast,
+        ];
+        threads.extend(verify_threads.into_iter());
+        Ok(threads)
+    }
+
+    /// This service receives messages from a leader in the network and processes the transactions
+    /// on the accountant state.
+    /// # Arguments
+    /// * `obj` - The accountant state.
+    /// * `me` - my configuration
+    /// * `leader` - leader configuration
+    /// * `exit` - The exit signal.
+    /// # Remarks
+    /// The pipeline is constructed as follows:
+    /// 1. receive blobs from the network, these are out of order
+    /// 2. verify blobs, PoH, signatures (TODO)
+    /// 3. reconstruct contiguous window
+    ///     a. order the blobs
+    ///     b. use erasure coding to reconstruct missing blobs
+    ///     c. ask the network for missing blobs, if erasure coding is insufficient
+    ///     d. make sure that the blobs PoH sequences connect (TODO)
+    /// 4. process the transaction state machine
+    /// 5. respond with the hash of the state back to the leader
+    pub fn replicate(
+        obj: &SharedTpu,
+        me: ReplicatedData,
+        gossip: UdpSocket,
+        serve: UdpSocket,
+        replicate: UdpSocket,
+        leader: ReplicatedData,
+        exit: Arc<AtomicBool>,
+    ) -> Result<Vec<JoinHandle<()>>> {
+        //replicate pipeline
+        let crdt = Arc::new(RwLock::new(Crdt::new(me)));
+        crdt.write().unwrap().set_leader(leader.id);
+        crdt.write().unwrap().insert(leader);
+        let t_gossip = Crdt::gossip(crdt.clone(), exit.clone());
+        let t_listen = Crdt::listen(crdt.clone(), gossip, exit.clone());
+
+        // make sure we are on the same interface
+        let mut local = replicate.local_addr()?;
+        local.set_port(0);
+        let write = UdpSocket::bind(local)?;
+
+        let blob_recycler = packet::BlobRecycler::default();
+        let (blob_sender, blob_receiver) = channel();
+        let t_blob_receiver = streamer::blob_receiver(
+            exit.clone(),
+            blob_recycler.clone(),
+            replicate,
+            blob_sender.clone(),
+        )?;
+        let (window_sender, window_receiver) = channel();
+        let (retransmit_sender, retransmit_receiver) = channel();
+
+        let t_retransmit = streamer::retransmitter(
+            write,
+            exit.clone(),
+            crdt.clone(),
+            blob_recycler.clone(),
+            retransmit_receiver,
+        );
+
+        //TODO
+        //the packets coming out of blob_receiver need to be sent to the GPU and verified
+        //then sent to the window, which does the erasure coding reconstruction
+        let t_window = streamer::window(
+            exit.clone(),
+            crdt.clone(),
+            blob_recycler.clone(),
+            blob_receiver,
+            window_sender,
+            retransmit_sender,
+        );
+
+        let tpu = obj.clone();
+        let s_exit = exit.clone();
+        let t_replicator = spawn(move || loop {
+            let e = Self::replicate_state(&tpu, &window_receiver, &blob_recycler);
+            if e.is_err() && s_exit.load(Ordering::Relaxed) {
+                break;
+            }
+        });
+
+        //serve pipeline
+        // make sure we are on the same interface
+        let mut local = serve.local_addr()?;
+        local.set_port(0);
+        let respond_socket = UdpSocket::bind(local.clone())?;
+
+        let packet_recycler = packet::PacketRecycler::default();
+        let blob_recycler = packet::BlobRecycler::default();
+        let (packet_sender, packet_receiver) = channel();
+        let t_packet_receiver =
+            streamer::receiver(serve, exit.clone(), packet_recycler.clone(), packet_sender)?;
+        let (responder_sender, responder_receiver) = channel();
+        let t_responder = streamer::responder(
+            respond_socket,
+            exit.clone(),
+            blob_recycler.clone(),
+            responder_receiver,
+        );
+        let (verified_sender, verified_receiver) = channel();
+
+        let mut verify_threads = Vec::new();
+        let shared_verified_sender = Arc::new(Mutex::new(verified_sender));
+        let shared_packet_receiver = Arc::new(Mutex::new(packet_receiver));
+        for _ in 0..4 {
+            let exit_ = exit.clone();
+            let recv = shared_packet_receiver.clone();
+            let sender = shared_verified_sender.clone();
+            let thread = spawn(move || loop {
+                let e = Self::verifier(&recv, &sender);
+                if e.is_err() && exit_.load(Ordering::Relaxed) {
+                    break;
+                }
+            });
+            verify_threads.push(thread);
+        }
+        let t_sync = Self::sync_no_broadcast_service(obj.clone(), exit.clone());
+
+        let tpu = obj.clone();
+        let s_exit = exit.clone();
+        let t_server = spawn(move || loop {
+            let e = Self::process(
+                &mut tpu.clone(),
+                &verified_receiver,
+                &responder_sender,
+                &packet_recycler,
+                &blob_recycler,
+            );
+            if e.is_err() {
+                if s_exit.load(Ordering::Relaxed) {
+                    break;
+                }
+            }
+        });
+
+        let mut threads = vec![
+            //replicate threads
+            t_blob_receiver,
+            t_retransmit,
+            t_window,
+            t_replicator,
+            t_gossip,
+            t_listen,
+            //serve threads
+            t_packet_receiver,
+            t_responder,
+            t_server,
+            t_sync,
+        ];
+        threads.extend(verify_threads.into_iter());
+        Ok(threads)
+    }
+}
+
+#[cfg(test)]
+pub fn to_packets(r: &packet::PacketRecycler, reqs: Vec<Request>) -> Vec<SharedPackets> {
+    let mut out = vec![];
+    for rrs in reqs.chunks(packet::NUM_PACKETS) {
+        let p = r.allocate();
+        p.write()
+            .unwrap()
+            .packets
+            .resize(rrs.len(), Default::default());
+        for (i, o) in rrs.iter().zip(p.write().unwrap().packets.iter_mut()) {
+            let v = serialize(&i).expect("serialize request");
+            let len = v.len();
+            o.data[..len].copy_from_slice(&v);
+            o.meta.size = len;
+        }
+        out.push(p);
+    }
+    return out;
+}
+
+#[cfg(test)]
+mod tests {
+    use bincode::serialize;
+    use ecdsa;
+    use packet::{BlobRecycler, PacketRecycler, BLOB_SIZE, NUM_PACKETS};
+    use tpu::{to_packets, Request};
+    use transaction::{memfind, test_tx};
+
+    use accountant::Accountant;
+    use chrono::prelude::*;
+    use crdt::Crdt;
+    use crdt::ReplicatedData;
+    use entry;
+    use entry::Entry;
+    use event::Event;
+    use futures::Future;
+    use hash::{hash, Hash};
+    use historian::Historian;
+    use logger;
+    use mint::Mint;
+    use plan::Plan;
+    use recorder::Signal;
+    use signature::{KeyPair, KeyPairUtil};
+    use std::collections::VecDeque;
+    use std::io::sink;
+    use std::net::UdpSocket;
+    use std::sync::atomic::{AtomicBool, Ordering};
+    use std::sync::mpsc::channel;
+    use std::sync::mpsc::sync_channel;
+    use std::sync::{Arc, RwLock};
+    use std::thread::sleep;
+    use std::time::Duration;
+    use streamer;
+    use thin_client::ThinClient;
+    use tpu::Tpu;
+    use transaction::Transaction;
+
+    #[test]
+    fn test_layout() {
+        let tr = test_tx();
+        let tx = serialize(&tr).unwrap();
+        let packet = serialize(&Request::Transaction(tr)).unwrap();
+        assert_matches!(memfind(&packet, &tx), Some(ecdsa::TX_OFFSET));
+        assert_matches!(memfind(&packet, &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]), None);
+    }
+    #[test]
+    fn test_to_packets() {
+        let tr = Request::Transaction(test_tx());
+        let re = PacketRecycler::default();
+        let rv = to_packets(&re, vec![tr.clone(); 1]);
+        assert_eq!(rv.len(), 1);
+        assert_eq!(rv[0].read().unwrap().packets.len(), 1);
+
+        let rv = to_packets(&re, vec![tr.clone(); NUM_PACKETS]);
+        assert_eq!(rv.len(), 1);
+        assert_eq!(rv[0].read().unwrap().packets.len(), NUM_PACKETS);
+
+        let rv = to_packets(&re, vec![tr.clone(); NUM_PACKETS + 1]);
+        assert_eq!(rv.len(), 2);
+        assert_eq!(rv[0].read().unwrap().packets.len(), NUM_PACKETS);
+        assert_eq!(rv[1].read().unwrap().packets.len(), 1);
+    }
+
+    #[test]
+    fn test_accounting_sequential_consistency() {
+        // In this attack we'll demonstrate that a verifier can interpret the ledger
+        // differently if either the server doesn't signal the ledger to add an
+        // Entry OR if the verifier tries to parallelize across multiple Entries.
+        let mint = Mint::new(2);
+        let acc = Accountant::new(&mint);
+        let (input, event_receiver) = sync_channel(10);
+        let historian = Historian::new(event_receiver, &mint.last_id(), None);
+        let tpu = Tpu::new(acc, input, historian);
+
+        // Process a batch that includes a transaction that receives two tokens.
+        let alice = KeyPair::new();
+        let tr = Transaction::new(&mint.keypair(), alice.pubkey(), 2, mint.last_id());
+        let events = vec![Event::Transaction(tr)];
+        assert!(tpu.process_events(events).is_ok());
+
+        // Process a second batch that spends one of those tokens.
+        let tr = Transaction::new(&alice, mint.pubkey(), 1, mint.last_id());
+        let events = vec![Event::Transaction(tr)];
+        assert!(tpu.process_events(events).is_ok());
+
+        // Collect the ledger and feed it to a new accountant.
+        tpu.historian_input
+            .lock()
+            .unwrap()
+            .send(Signal::Tick)
+            .unwrap();
+        drop(tpu.historian_input);
+        let entries: Vec<Entry> = tpu.historian.output.lock().unwrap().iter().collect();
+
+        // Assert the user holds one token, not two. If the server only output one
+        // entry, then the second transaction will be rejected, because it drives
+        // the account balance below zero before the credit is added.
+        let acc = Accountant::new(&mint);
+        for entry in entries {
+            assert!(
+                acc.process_verified_events(entry.events)
+                    .into_iter()
+                    .all(|x| x.is_ok())
+            );
+        }
+        assert_eq!(acc.get_balance(&alice.pubkey()), Some(1));
+    }
+
+    #[test]
+    fn test_accountant_bad_sig() {
+        let (leader_data, leader_gossip, _, leader_serve, leader_skinny) = test_node();
+        let alice = Mint::new(10_000);
+        let acc = Accountant::new(&alice);
+        let bob_pubkey = KeyPair::new().pubkey();
+        let exit = Arc::new(AtomicBool::new(false));
+        let (input, event_receiver) = sync_channel(10);
+        let historian = Historian::new(event_receiver, &alice.last_id(), Some(30));
+        let tpu = Arc::new(Tpu::new(acc, input, historian));
+        let serve_addr = leader_serve.local_addr().unwrap();
+        let threads = Tpu::serve(
+            &tpu,
+            leader_data,
+            leader_serve,
+            leader_skinny,
+            leader_gossip,
+            exit.clone(),
+            sink(),
+        ).unwrap();
+        sleep(Duration::from_millis(300));
+
+        let socket = UdpSocket::bind("127.0.0.1:0").unwrap();
+        socket.set_read_timeout(Some(Duration::new(5, 0))).unwrap();
+        let mut client = ThinClient::new(serve_addr, socket);
+        let last_id = client.get_last_id().wait().unwrap();
+
+        trace!("doing stuff");
+
+        let tr = Transaction::new(&alice.keypair(), bob_pubkey, 500, last_id);
+
+        let _sig = client.transfer_signed(tr).unwrap();
+
+        let last_id = client.get_last_id().wait().unwrap();
+
+        let mut tr2 = Transaction::new(&alice.keypair(), bob_pubkey, 501, last_id);
+        tr2.data.tokens = 502;
+        tr2.data.plan = Plan::new_payment(502, bob_pubkey);
+        let _sig = client.transfer_signed(tr2).unwrap();
+
+        assert_eq!(client.get_balance(&bob_pubkey).unwrap(), 500);
+        trace!("exiting");
+        exit.store(true, Ordering::Relaxed);
+        trace!("joining threads");
+        for t in threads {
+            t.join().unwrap();
+        }
+    }
+
+    fn test_node() -> (ReplicatedData, UdpSocket, UdpSocket, UdpSocket, UdpSocket) {
+        let skinny = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let gossip = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let replicate = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let serve = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let pubkey = KeyPair::new().pubkey();
+        let d = ReplicatedData::new(
+            pubkey,
+            gossip.local_addr().unwrap(),
+            replicate.local_addr().unwrap(),
+            serve.local_addr().unwrap(),
+        );
+        (d, gossip, replicate, serve, skinny)
+    }
+
+    /// Test that mesasge sent from leader to target1 and repliated to target2
+    #[test]
+    fn test_replicate() {
+        logger::setup();
+        let (leader_data, leader_gossip, _, leader_serve, _) = test_node();
+        let (target1_data, target1_gossip, target1_replicate, target1_serve, _) = test_node();
+        let (target2_data, target2_gossip, target2_replicate, _, _) = test_node();
+        let exit = Arc::new(AtomicBool::new(false));
+
+        //start crdt_leader
+        let mut crdt_l = Crdt::new(leader_data.clone());
+        crdt_l.set_leader(leader_data.id);
+
+        let cref_l = Arc::new(RwLock::new(crdt_l));
+        let t_l_gossip = Crdt::gossip(cref_l.clone(), exit.clone());
+        let t_l_listen = Crdt::listen(cref_l, leader_gossip, exit.clone());
+
+        //start crdt2
+        let mut crdt2 = Crdt::new(target2_data.clone());
+        crdt2.insert(leader_data.clone());
+        crdt2.set_leader(leader_data.id);
+        let leader_id = leader_data.id;
+        let cref2 = Arc::new(RwLock::new(crdt2));
+        let t2_gossip = Crdt::gossip(cref2.clone(), exit.clone());
+        let t2_listen = Crdt::listen(cref2, target2_gossip, exit.clone());
+
+        // setup some blob services to send blobs into the socket
+        // to simulate the source peer and get blobs out of the socket to
+        // simulate target peer
+        let recv_recycler = BlobRecycler::default();
+        let resp_recycler = BlobRecycler::default();
+        let (s_reader, r_reader) = channel();
+        let t_receiver = streamer::blob_receiver(
+            exit.clone(),
+            recv_recycler.clone(),
+            target2_replicate,
+            s_reader,
+        ).unwrap();
+
+        // simulate leader sending messages
+        let (s_responder, r_responder) = channel();
+        let t_responder = streamer::responder(
+            leader_serve,
+            exit.clone(),
+            resp_recycler.clone(),
+            r_responder,
+        );
+
+        let starting_balance = 10_000;
+        let alice = Mint::new(starting_balance);
+        let acc = Accountant::new(&alice);
+        let (input, event_receiver) = sync_channel(10);
+        let historian = Historian::new(event_receiver, &alice.last_id(), Some(30));
+        let acc = Arc::new(Tpu::new(acc, input, historian));
+        let replicate_addr = target1_data.replicate_addr;
+        let threads = Tpu::replicate(
+            &acc,
+            target1_data,
+            target1_gossip,
+            target1_serve,
+            target1_replicate,
+            leader_data,
+            exit.clone(),
+        ).unwrap();
+
+        let mut alice_ref_balance = starting_balance;
+        let mut msgs = VecDeque::new();
+        let mut cur_hash = Hash::default();
+        let num_blobs = 10;
+        let transfer_amount = 501;
+        let bob_keypair = KeyPair::new();
+        for i in 0..num_blobs {
+            let b = resp_recycler.allocate();
+            let b_ = b.clone();
+            let mut w = b.write().unwrap();
+            w.set_index(i).unwrap();
+            w.set_id(leader_id).unwrap();
+
+            let tr0 = Event::new_timestamp(&bob_keypair, Utc::now());
+            let entry0 = entry::create_entry(&cur_hash, i, vec![tr0]);
+            acc.acc.lock().unwrap().register_entry_id(&cur_hash);
+            cur_hash = hash(&cur_hash);
+
+            let tr1 = Transaction::new(
+                &alice.keypair(),
+                bob_keypair.pubkey(),
+                transfer_amount,
+                cur_hash,
+            );
+            acc.acc.lock().unwrap().register_entry_id(&cur_hash);
+            cur_hash = hash(&cur_hash);
+            let entry1 =
+                entry::create_entry(&cur_hash, i + num_blobs, vec![Event::Transaction(tr1)]);
+            acc.acc.lock().unwrap().register_entry_id(&cur_hash);
+            cur_hash = hash(&cur_hash);
+
+            alice_ref_balance -= transfer_amount;
+
+            let serialized_entry = serialize(&vec![entry0, entry1]).unwrap();
+
+            w.data_mut()[..serialized_entry.len()].copy_from_slice(&serialized_entry);
+            w.set_size(serialized_entry.len());
+            w.meta.set_addr(&replicate_addr);
+            drop(w);
+            msgs.push_back(b_);
+        }
+
+        // send the blobs into the socket
+        s_responder.send(msgs).expect("send");
+
+        // receive retransmitted messages
+        let timer = Duration::new(1, 0);
+        let mut msgs: Vec<_> = Vec::new();
+        while let Ok(msg) = r_reader.recv_timeout(timer) {
+            trace!("msg: {:?}", msg);
+            msgs.push(msg);
+        }
+
+        let alice_balance = acc.acc
+            .lock()
+            .unwrap()
+            .get_balance(&alice.keypair().pubkey())
+            .unwrap();
+        assert_eq!(alice_balance, alice_ref_balance);
+
+        let bob_balance = acc.acc
+            .lock()
+            .unwrap()
+            .get_balance(&bob_keypair.pubkey())
+            .unwrap();
+        assert_eq!(bob_balance, starting_balance - alice_ref_balance);
+
+        exit.store(true, Ordering::Relaxed);
+        for t in threads {
+            t.join().expect("join");
+        }
+        t2_gossip.join().expect("join");
+        t2_listen.join().expect("join");
+        t_receiver.join().expect("join");
+        t_responder.join().expect("join");
+        t_l_gossip.join().expect("join");
+        t_l_listen.join().expect("join");
+    }
+
+    #[test]
+    fn test_entry_to_blobs() {
+        let zero = Hash::default();
+        let keypair = KeyPair::new();
+        let tr0 = Event::Transaction(Transaction::new(&keypair, keypair.pubkey(), 0, zero));
+        let tr1 = Event::Transaction(Transaction::new(&keypair, keypair.pubkey(), 1, zero));
+        let e0 = entry::create_entry(&zero, 0, vec![tr0.clone(), tr1.clone()]);
+
+        let entry_list = vec![e0; 1000];
+        let blob_recycler = BlobRecycler::default();
+        let mut blob_q = VecDeque::new();
+        Tpu::process_entry_list_into_blobs(&entry_list, &blob_recycler, &mut blob_q);
+        let serialized_entry_list = serialize(&entry_list).unwrap();
+        let mut num_blobs_ref = serialized_entry_list.len() / BLOB_SIZE;
+        if serialized_entry_list.len() % BLOB_SIZE != 0 {
+            num_blobs_ref += 1
+        }
+        trace!("len: {} ref_len: {}", blob_q.len(), num_blobs_ref);
+        assert!(blob_q.len() > num_blobs_ref);
+    }
+}
+
+#[cfg(all(feature = "unstable", test))]
+mod bench {
+    extern crate test;
+    use self::test::Bencher;
+    use accountant::{Accountant, MAX_ENTRY_IDS};
+    use bincode::serialize;
+    use hash::hash;
+    use mint::Mint;
+    use signature::{KeyPair, KeyPairUtil};
+    use std::collections::HashSet;
+    use std::sync::mpsc::sync_channel;
+    use std::time::Instant;
+    use tpu::*;
+    use transaction::Transaction;
+
+    #[bench]
+    fn process_packets_bench(_bencher: &mut Bencher) {
+        let mint = Mint::new(100_000_000);
+        let acc = Accountant::new(&mint);
+        let rsp_addr: SocketAddr = "0.0.0.0:0".parse().expect("socket address");
+        // Create transactions between unrelated parties.
+        let txs = 100_000;
+        let last_ids: Mutex<HashSet<Hash>> = Mutex::new(HashSet::new());
+        let transactions: Vec<_> = (0..txs)
+            .into_par_iter()
+            .map(|i| {
+                // Seed the 'to' account and a cell for its signature.
+                let dummy_id = i % (MAX_ENTRY_IDS as i32);
+                let last_id = hash(&serialize(&dummy_id).unwrap()); // Semi-unique hash
+                {
+                    let mut last_ids = last_ids.lock().unwrap();
+                    if !last_ids.contains(&last_id) {
+                        last_ids.insert(last_id);
+                        acc.register_entry_id(&last_id);
+                    }
+                }
+
+                // Seed the 'from' account.
+                let rando0 = KeyPair::new();
+                let tr = Transaction::new(&mint.keypair(), rando0.pubkey(), 1_000, last_id);
+                acc.process_verified_transaction(&tr).unwrap();
+
+                let rando1 = KeyPair::new();
+                let tr = Transaction::new(&rando0, rando1.pubkey(), 2, last_id);
+                acc.process_verified_transaction(&tr).unwrap();
+
+                // Finally, return a transaction that's unique
+                Transaction::new(&rando0, rando1.pubkey(), 1, last_id)
+            })
+            .collect();
+
+        let req_vers = transactions
+            .into_iter()
+            .map(|tr| (Request::Transaction(tr), rsp_addr, 1_u8))
+            .collect();
+
+        let (input, event_receiver) = sync_channel(10);
+        let historian = Historian::new(event_receiver, &mint.last_id(), None);
+        let tpu = Tpu::new(acc, input, historian);
+
+        let now = Instant::now();
+        assert!(tpu.process_events(req_vers).is_ok());
+        let duration = now.elapsed();
+        let sec = duration.as_secs() as f64 + duration.subsec_nanos() as f64 / 1_000_000_000.0;
+        let tps = txs as f64 / sec;
+
+        // Ensure that all transactions were successfully logged.
+        drop(tpu.historian_input);
+        let entries: Vec<Entry> = tpu.historian.output.lock().unwrap().iter().collect();
+        assert_eq!(entries.len(), 1);
+        assert_eq!(entries[0].events.len(), txs as usize);
+
+        println!("{} tps", tps);
+    }
+}