diff --git a/Cargo.lock b/Cargo.lock
index 7cbaa14..0eed395 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -839,6 +839,7 @@ name = "turnhammer"
 version = "0.1.0"
 dependencies = [
  "bytecodec 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "spin_sleep 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/Cargo.toml b/Cargo.toml
index 0d923eb..15ee319 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,6 +17,7 @@ stunclient = "0.1.1"
 turnclient = "0.1.0"
 spin_sleep = "0.3.7"
 tokio-timer = "0.2.10"
+byteorder = "1.3.1"
 
 [replace]
 "stun_codec:0.1.10" = {path = "/mnt/src/git/stun_codec"}
diff --git a/src/main.rs b/src/main.rs
index 7773c64..1286355 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,10 +9,12 @@ extern crate turnclient;
 extern crate tokio;
 extern crate spin_sleep;
 extern crate tokio_timer;
+extern crate byteorder;
 
 use std::time::{Duration,Instant};
 use std::net::SocketAddr;
 use structopt::StructOpt;
+use std::sync::Arc;
 
 use futures::{Async, Future, Poll};
 use futures::{Stream, Sink};
@@ -54,7 +56,7 @@ struct Opt {
 
     /// Packets per second
     #[structopt(long="pps", default_value="5")]
-    delay_between_packets: u32,
+    packets_per_second: u32,
 
     /// Experiment duration, seconds
     #[structopt(short="d", long="duration", default_value="5")]
@@ -74,11 +76,67 @@ enum ServeTurnEventOrShutdown {
     Shutdown,
 }
 
+fn sending_thread(
+    udp: Arc<std::net::UdpSocket>,
+    packet_size: usize,
+    packets_per_second: u32,
+    duration_seconds: u64,
+    destinations: Vec<SocketAddr>,
+    time_base: Instant,
+) {
+    let sleeper = spin_sleep::SpinSleeper::default();
+    sleeper.sleep_ns(500_000_000); // to allow receiver to warm up
+    let start = Instant::now();
+    let step = Duration::from_secs(1) / packets_per_second;
+    let n = packets_per_second * (duration_seconds as u32);
+
+    use byteorder::{BE,ByteOrder};
+
+    let mut buf = vec![0; packet_size];
+
+    let mut totalctr : u32 = 0;
+
+    for i in 0..n {
+        let deadline = start + step * i;
+        let now = Instant::now();
+        let delta = now - time_base;
+
+        BE::write_u64(&mut buf[0..8], delta.as_secs());
+        BE::write_u32(&mut buf[8..12], delta.subsec_nanos());
+
+        if now < deadline {
+            sleeper.sleep(deadline - now);
+        }
+
+        let udp = &*udp;
+        for addr in &destinations {
+            BE::write_u32(&mut buf[12..16], totalctr);
+            udp.send_to(&buf[..], addr).expect("UDP send_to failed");
+            totalctr+=1;
+        }
+    }
+}
+
+fn receiving_thread(
+    udp: Arc<std::net::UdpSocket>,
+    duration_seconds: u64,
+    packet_size: usize,
+    time_base: Instant,
+) {
+    let mut buf = vec![0; packet_size];
+    loop {
+        let (_len, _addr) = udp.recv_from(&mut buf[..]).expect("Failed to receive packet");
+        println!("Received a packet from {}", _addr);
+    }
+}
+
 fn main() -> Result<(), Error> {
     let opt = Opt::from_args();
 
     let local_addr: SocketAddr = "0.0.0.0:0".parse().unwrap();
     let probing_udp = std::net::UdpSocket::bind(local_addr)?;
+    let probing_udp = Arc::new(probing_udp);
+    let time_base = Instant::now();
 
     // Phase 1: Query my own external address
     let extaddr = stunclient::StunClient::new(opt.server)
@@ -91,6 +149,8 @@ fn main() -> Result<(), Error> {
     let k = opt.num_connections;
     let duration = opt.duration;
     let delay_after_stopping_sender = opt.delay_after_stopping_sender;
+    let packet_size = opt.packet_size;
+    let pps = opt.packets_per_second;
 
     let clientstream = futures::stream::repeat::<_,Error>(
         (opt.server, opt.username, opt.password),
@@ -149,18 +209,39 @@ fn main() -> Result<(), Error> {
     let clienthandles = clienthandles.and_then(move |x|{
         let (init_handles, shutdown_handles) : (Vec<_>, Vec<_>) = x.into_iter().unzip();
         futures::future::join_all(init_handles)
-        .and_then(|h| {
-            eprintln!("Allocated {} TURN clients", h.len());
-            futures::future::ok(())
-        })
         .map_err(|_e|Error::from("Oneshot error"))
-        .and_then(move |()| {
+        .and_then(move |destinations| {
+            eprintln!("Allocated {} TURN clients", destinations.len());
+            // Phase 3: Starting sender and receiver
+
+            let probing_udp2 = probing_udp.clone();
+            std::thread::spawn(move || {
+                sending_thread(
+                    probing_udp2,
+                    packet_size,
+                    pps,
+                    duration,
+                    destinations,
+                    time_base,
+                );
+            });
+            std::thread::spawn(move || {
+                receiving_thread(
+                    probing_udp,
+                    duration,
+                    packet_size, 
+                    time_base,
+                );
+            });
+
             tokio_timer::Delay::new(
                 Instant::now() + 
                 Duration::from_secs(
                     duration + delay_after_stopping_sender
                 )
             ).and_then(|()| {
+                // Phase 4: Stopping
+
                 eprintln!("Stopping TURN clients");
                 for sh in shutdown_handles {
                     sh.send(());