diff --git a/README.md b/README.md
index 2bfd145..6cda015 100644
--- a/README.md
+++ b/README.md
@@ -17,9 +17,9 @@ const c = require('compact-encoding')
 
 const mux = new Protomux(aStreamThatFrames)
 
-// Now add some protocol sessions
+// Now add some protocol channels
 
-const cool = mux.open({
+const cool = mux.createChannel({
   protocol: 'cool-protocol',
   id: Buffer.from('optional binary id'),
   onopen () {
@@ -46,6 +46,11 @@ const two = cool.addMessage({
   }
 })
 
+// open the channels
+
+one.open()
+two.open()
+
 // And send some data
 
 one.send('a string')
@@ -71,9 +76,9 @@ Options include:
 
 Helper to accept either an existing muxer instance or a stream (which creates a new one).
 
-#### `const session = mux.open(opts)`
+#### `const channel = mux.createChannel(opts)`
 
-Add a new protocol session.
+Add a new protocol channel.
 
 Options include:
 
@@ -81,14 +86,16 @@ Options include:
 {
   // Used to match the protocol
   protocol: 'name of the protocol',
-  // Optional additional binary id to identify this session
+  // Optional additional binary id to identify this channel
   id: buffer,
+  // Optional encoding for a handshake
+  handshake: encoding,
   // Optional array of messages types you want to send/receive.
   messages: [],
   // Called when the remote side adds this protocol.
   // Errors here are caught and forwared to stream.destroy
-  async onopen () {},
-  // Called when the session closes - ie the remote side closes or rejects this protocol or we closed it.
+  async onopen (handshake) {},
+  // Called when the channel closes - ie the remote side closes or rejects this protocol or we closed it.
   // Errors here are caught and forwared to stream.destroy
   async onclose () {},
   // Called after onclose when all pending promises has resolved.
@@ -96,13 +103,17 @@ Options include:
 }
 ```
 
-Sessions are paired based on a queue, so the first remote session with the same `protocol` and `id`.
+Sessions are paired based on a queue, so the first remote channel with the same `protocol` and `id`.
 
-__NOTE__: `mux.open` returns `null` if the session should not be opened, ie it's a duplicate session or the remote has already closed this one.
+__NOTE__: `mux.createChannel` returns `null` if the channel should not be opened, ie it's a duplicate channel or the remote has already closed this one.
 
 If you want multiple sessions with the same `protocol` and `id`, set `unique: false` as an option.
 
-#### `const m = session.addMessage(opts)`
+#### `channel.open([handshake])`
+
+Open the channel.
+
+#### `const m = channel.addMessage(opts)`
 
 Add a message. Options include:
 
@@ -128,25 +139,25 @@ Function that is called when a message arrives.
 
 The encoding for this message.
 
-#### `session.close()`
+#### `channel.close()`
 
-Closes the protocol session.
+Closes the protocol channel.
 
-#### `sessoin.cork()`
+#### `channel.cork()`
 
-Corking the protocol session, makes it buffer messages and send them all in a batch when it uncorks.
+Corking the protocol channel, makes it buffer messages and send them all in a batch when it uncorks.
 
-#### `session.uncork()`
+#### `channel.uncork()`
 
 Uncork and send the batch.
 
 #### `mux.cork()`
 
-Same as `session.cork` but on the muxer instance.
+Same as `channel.cork` but on the muxer instance.
 
 #### `mux.uncork()`
 
-Same as `session.uncork` but on the muxer instance.
+Same as `channel.uncork` but on the muxer instance.
 
 ## License
 
diff --git a/index.js b/index.js
index cf0b25f..25462b3 100644
--- a/index.js
+++ b/index.js
@@ -6,13 +6,13 @@ const safetyCatch = require('safety-catch')
 const MAX_BUFFERED = 32768
 const MAX_BACKLOG = Infinity // TODO: impl "open" backpressure
 
-class Session {
-  constructor (mux, info, context, protocol, id, messages, onopen, onclose, ondestroy) {
-    this.context = context
+class Channel {
+  constructor (mux, info, userData, protocol, id, handshake, messages, onopen, onclose, ondestroy) {
+    this.userData = userData
     this.protocol = protocol
     this.id = id
+    this.handshake = null
     this.messages = []
-    this.remoteMessages = this.messages
 
     this.opened = false
     this.closed = false
@@ -22,6 +22,7 @@ class Session {
     this.onclose = onclose
     this.ondestroy = ondestroy
 
+    this._handshake = handshake
     this._mux = mux
     this._info = info
     this._localId = 0
@@ -35,7 +36,7 @@ class Session {
     for (const m of messages) this.addMessage(m)
   }
 
-  _open () {
+  open (handshake) {
     const id = this._mux._free.length > 0
       ? this._mux._free.pop()
       : this._mux._local.push(null) - 1
@@ -44,19 +45,25 @@ class Session {
     this._localId = id + 1
     this._mux._local[id] = this
 
+    if (this._remoteId === 0) {
+      this._info.outgoing.push(this._localId)
+    }
+
     const state = { buffer: null, start: 2, end: 2 }
 
+    c.uint.preencode(state, this._localId)
     c.string.preencode(state, this.protocol)
     c.buffer.preencode(state, this.id)
-    c.uint.preencode(state, this._localId)
+    if (this._handshake) this._handshake.preencode(state, handshake)
 
     state.buffer = this._mux._alloc(state.end)
 
     state.buffer[0] = 0
     state.buffer[1] = 1
+    c.uint.encode(state, this._localId)
     c.string.encode(state, this.protocol)
     c.buffer.encode(state, this.id)
-    c.uint.encode(state, this._localId)
+    if (this._handshake) this._handshake.encode(state, handshake)
 
     this._mux._write0(state.buffer)
   }
@@ -81,9 +88,11 @@ class Session {
     const remote = this._mux._remote[this._remoteId - 1]
 
     this.opened = true
-    this._track(this.onopen(this))
+    this.handshake = this._handshake ? this._handshake.decode(remote.state) : null
+    this._track(this.onopen(this.handshake, this))
 
     remote.session = this
+    remote.state = null
     if (remote.pending !== null) this._drain(remote)
   }
 
@@ -135,8 +144,8 @@ class Session {
   }
 
   _recv (type, state) {
-    if (type < this.remoteMessages.length) {
-      this.remoteMessages[type].recv(state, this)
+    if (type < this.messages.length) {
+      this.messages[type].recv(state, this)
     }
   }
 
@@ -302,17 +311,14 @@ module.exports = class Protomux {
     return info ? info.opened > 0 : false
   }
 
-  open ({ context = null, protocol, id = null, unique = true, messages = [], onopen = noop, onclose = noop, ondestroy = noop }) {
+  createChannel ({ userData = null, protocol, id = null, unique = true, handshake = null, messages = [], onopen = noop, onclose = noop, ondestroy = noop }) {
     if (this.stream.destroyed) return null
 
     const info = this._get(protocol, id)
     if (unique && info.opened > 0) return null
 
     if (info.incoming.length === 0) {
-      const session = new Session(this, info, context, protocol, id, messages, onopen, onclose, ondestroy)
-      session._open()
-      info.outgoing.push(session._localId)
-      return session
+      return new Channel(this, info, userData, protocol, id, handshake, messages, onopen, onclose, ondestroy)
     }
 
     this._remoteBacklog--
@@ -321,10 +327,9 @@ module.exports = class Protomux {
     const r = this._remote[remoteId - 1]
     if (r === null) return null
 
-    const session = new Session(this, info, context, protocol, id, messages, onopen, onclose, ondestroy)
+    const session = new Channel(this, info, userData, protocol, id, handshake, messages, onopen, onclose, ondestroy)
 
     session._remoteId = remoteId
-    session._open()
     session._fullyOpenSoon()
 
     return session
@@ -465,9 +470,9 @@ module.exports = class Protomux {
   }
 
   _onopensession (state) {
+    const remoteId = c.uint.decode(state)
     const protocol = c.string.decode(state)
     const id = c.buffer.decode(state)
-    const remoteId = c.uint.decode(state)
 
     // remote tried to open the control session - auto reject for now
     // as we can use as an explicit control protocol declaration if we need to
@@ -497,14 +502,14 @@ module.exports = class Protomux {
         return
       }
 
-      this._remote[rid] = { pending: null, session: null }
+      this._remote[rid] = { state, pending: null, session: null }
 
       session._remoteId = remoteId
       session._fullyOpen()
       return
     }
 
-    this._remote[rid] = { pending: [], session: null }
+    this._remote[rid] = { state, pending: [], session: null }
 
     if (++this._remoteBacklog > MAX_BACKLOG) {
       throw new Error('Remote exceeded backlog')
@@ -517,19 +522,25 @@ module.exports = class Protomux {
   }
 
   _onrejectsession (state) {
-    const protocol = c.string.decode(state)
-    const id = c.buffer.decode(state)
-    const info = this._get(protocol, id)
+    const localId = c.uint.decode(state)
 
-    if (info.outgoing.length === 0) {
-      throw new Error('Invalid reject message')
+    // TODO: can be done smarter...
+    for (const info of this._infos.values()) {
+      const i = info.outgoing.indexOf(localId)
+      if (i === -1) continue
+
+      info.outgoing.splice(i, 1)
+
+      const session = this._local[localId - 1]
+
+      this._free.push(localId - 1)
+      if (session !== null) session._close(true)
+
+      this._gc(info)
+      return
     }
 
-    const localId = info.outgoing.shift()
-    const session = this._local[localId - 1]
-
-    this._free.push(localId - 1)
-    if (session !== null) session._close(true)
+    throw new Error('Invalid reject message')
   }
 
   _onclosesession (state) {
@@ -553,7 +564,7 @@ module.exports = class Protomux {
     if (--info.pairing > 0) return
 
     while (info.incoming.length > 0) {
-      this._rejectSession(info, info.incoming.pop())
+      this._rejectSession(info, info.incoming.shift())
     }
 
     this._gc(info)
@@ -575,15 +586,13 @@ module.exports = class Protomux {
 
     const state = { buffer: null, start: 2, end: 2 }
 
-    c.string.preencode(state, info.protocol)
-    c.buffer.preencode(state, info.id)
+    c.uint.preencode(state, remoteId)
 
     state.buffer = this._alloc(state.end)
 
     state.buffer[0] = 0
     state.buffer[1] = 2
-    c.string.encode(state, info.protocol)
-    c.buffer.encode(state, info.id)
+    c.uint.encode(state, remoteId)
 
     this._write0(state.buffer)
   }
diff --git a/test.js b/test.js
index a6d017c..af58cd0 100644
--- a/test.js
+++ b/test.js
@@ -9,13 +9,15 @@ test('basic', function (t) {
 
   replicate(a, b)
 
-  const p = a.open({
+  const p = a.createChannel({
     protocol: 'foo',
     onopen () {
       t.pass('a remote opened')
     }
   })
 
+  p.open()
+
   p.addMessage({
     encoding: c.string,
     onmessage (message) {
@@ -23,12 +25,13 @@ test('basic', function (t) {
     }
   })
 
-  const bp = b.open({
+  const bp = b.createChannel({
     protocol: 'foo'
   })
 
   t.plan(2)
 
+  bp.open()
   bp.addMessage({ encoding: c.string }).send('hello world')
 })
 
@@ -38,10 +41,12 @@ test('echo message', function (t) {
 
   replicate(a, b)
 
-  const ap = a.open({
+  const ap = a.createChannel({
     protocol: 'foo'
   })
 
+  ap.open()
+
   const aEcho = ap.addMessage({
     encoding: c.string,
     onmessage (message) {
@@ -49,17 +54,19 @@ test('echo message', function (t) {
     }
   })
 
-  b.open({
+  b.createChannel({
     protocol: 'other'
-  })
+  }).open()
 
-  const bp = b.open({
+  const bp = b.createChannel({
     protocol: 'foo',
     onopen () {
       t.pass('b remote opened')
     }
   })
 
+  bp.open()
+
   const bEcho = bp.addMessage({
     encoding: c.string,
     onmessage (message) {
@@ -75,24 +82,28 @@ test('echo message', function (t) {
 test('multi message', function (t) {
   const a = new Protomux(new SecretStream(true))
 
-  a.open({
+  a.createChannel({
     protocol: 'other'
-  })
+  }).open()
 
-  const ap = a.open({
+  const ap = a.createChannel({
     protocol: 'multi'
   })
 
+  ap.open()
+
   const a1 = ap.addMessage({ encoding: c.int })
   const a2 = ap.addMessage({ encoding: c.string })
   const a3 = ap.addMessage({ encoding: c.string })
 
   const b = new Protomux(new SecretStream(false))
 
-  const bp = b.open({
+  const bp = b.createChannel({
     protocol: 'multi'
   })
 
+  bp.open()
+
   const b1 = bp.addMessage({ encoding: c.int })
   const b2 = bp.addMessage({ encoding: c.string })
 
@@ -123,23 +134,27 @@ test('corks', function (t) {
 
   a.cork()
 
-  a.open({
+  a.createChannel({
     protocol: 'other'
-  })
+  }).open()
 
-  const ap = a.open({
+  const ap = a.createChannel({
     protocol: 'multi'
   })
 
+  ap.open()
+
   const a1 = ap.addMessage({ encoding: c.int })
   const a2 = ap.addMessage({ encoding: c.string })
 
   const b = new Protomux(new SecretStream(false))
 
-  const bp = b.open({
+  const bp = b.createChannel({
     protocol: 'multi'
   })
 
+  bp.open()
+
   const b1 = bp.addMessage({ encoding: c.int })
   const b2 = bp.addMessage({ encoding: c.string })
 
@@ -174,6 +189,82 @@ test('corks', function (t) {
   }
 })
 
+test('handshake', function (t) {
+  const a = new Protomux(new SecretStream(true))
+  const b = new Protomux(new SecretStream(false))
+
+  replicate(a, b)
+
+  const p = a.createChannel({
+    protocol: 'foo',
+    handshake: c.string,
+    onopen (handshake) {
+      t.is(handshake, 'b handshake')
+    }
+  })
+
+  p.open('a handshake')
+
+  const bp = b.createChannel({
+    protocol: 'foo',
+    handshake: c.string,
+    onopen (handshake) {
+      t.is(handshake, 'a handshake')
+    }
+  })
+
+  t.plan(2)
+
+  bp.open('b handshake')
+})
+
+test('rejections', function (t) {
+  t.plan(1)
+
+  const a = new Protomux(new SecretStream(true))
+  const b = new Protomux(new SecretStream(false))
+
+  replicate(a, b)
+
+  let closed = 0
+  for (let i = 0; i < 10; i++) {
+    const p = a.createChannel({
+      protocol: 'foo#' + i,
+      onclose () {
+        closed++
+        if (closed === 10) t.pass('all closed')
+      }
+    })
+
+    p.open()
+  }
+})
+
+test('pipeline close and rejections', function (t) {
+  t.plan(1)
+
+  const a = new Protomux(new SecretStream(true))
+  const b = new Protomux(new SecretStream(false))
+
+  replicate(a, b)
+
+  let closed = 0
+  for (let i = 0; i < 10; i++) {
+    const p = a.createChannel({
+      protocol: 'foo#' + i,
+      onclose () {
+        closed++
+        if (closed === 10) {
+          t.pass('all closed')
+        }
+      }
+    })
+
+    p.open()
+    p.close()
+  }
+})
+
 function replicate (a, b) {
   a.stream.rawStream.pipe(b.stream.rawStream).pipe(a.stream.rawStream)
 }