diff --git a/package.json b/package.json
index db94adc3..4abc96c8 100644
--- a/package.json
+++ b/package.json
@@ -41,6 +41,7 @@
     "npm": ">=6.0.0"
   },
   "dependencies": {
+    "abort-controller": "^3.0.0",
     "async": "^2.6.2",
     "bignumber.js": "^9.0.0",
     "class-is": "^1.1.0",
@@ -48,15 +49,17 @@
     "err-code": "^1.1.2",
     "fsm-event": "^2.1.0",
     "hashlru": "^2.3.0",
-    "interface-connection": "~0.3.3",
+    "it-pipe": "^1.0.1",
     "latency-monitor": "~0.2.1",
     "libp2p-crypto": "^0.16.2",
+    "libp2p-interfaces": "^0.1.1",
     "mafmt": "^7.0.0",
     "merge-options": "^1.0.1",
     "moving-average": "^1.0.0",
     "multiaddr": "^7.1.0",
-    "multistream-select": "~0.14.6",
+    "multistream-select": "^0.15.0",
     "once": "^1.4.0",
+    "p-queue": "^6.1.1",
     "p-settle": "^3.1.0",
     "peer-book": "^0.9.1",
     "peer-id": "^0.13.3",
@@ -73,6 +76,7 @@
   },
   "devDependencies": {
     "@nodeutils/defaults-deep": "^1.1.0",
+    "abortable-iterator": "^2.1.0",
     "aegir": "^20.0.0",
     "chai": "^4.2.0",
     "chai-checkmark": "^1.0.1",
@@ -80,7 +84,9 @@
     "delay": "^4.3.0",
     "dirty-chai": "^2.0.1",
     "electron-webrtc": "^0.3.0",
+    "glob": "^7.1.4",
     "interface-datastore": "^0.6.0",
+    "it-pair": "^1.0.0",
     "libp2p-bootstrap": "^0.9.7",
     "libp2p-delegated-content-routing": "^0.2.2",
     "libp2p-delegated-peer-routing": "^0.2.2",
@@ -88,7 +94,7 @@
     "libp2p-gossipsub": "~0.0.4",
     "libp2p-kad-dht": "^0.15.3",
     "libp2p-mdns": "^0.12.3",
-    "libp2p-mplex": "^0.8.4",
+    "libp2p-mplex": "^0.9.1",
     "libp2p-pnet": "~0.1.0",
     "libp2p-secio": "^0.11.1",
     "libp2p-spdy": "^0.13.2",
@@ -96,6 +102,7 @@
     "libp2p-websockets": "^0.13.0",
     "lodash.times": "^4.3.2",
     "nock": "^10.0.6",
+    "p-defer": "^3.0.0",
     "portfinder": "^1.0.20",
     "pull-goodbye": "0.0.2",
     "pull-length-prefixed": "^1.3.3",
@@ -104,6 +111,7 @@
     "pull-protocol-buffers": "~0.1.2",
     "pull-serializer": "^0.3.2",
     "sinon": "^7.2.7",
+    "streaming-iterables": "^4.1.0",
     "wrtc": "^0.4.1"
   },
   "contributors": [
diff --git a/src/circuit/README.md b/src/circuit/README.md
index 5c67474d..36b659f7 100644
--- a/src/circuit/README.md
+++ b/src/circuit/README.md
@@ -1,6 +1,6 @@
 # js-libp2p-circuit
 
-> Node.js implementation of the Circuit module that libp2p uses, which implements the [interface-connection](https://github.com/libp2p/interface-connection) interface for dial/listen.
+> Node.js implementation of the Circuit module that libp2p uses, which implements the [interface-connection](https://github.com/libp2p/js-interfaces/tree/master/src/connection) interface for dial/listen.
 
 **Note**: git history prior to merging into js-libp2p can be found in the original repository, https://github.com/libp2p/js-libp2p-circuit.
 
@@ -24,15 +24,18 @@ Prior to `libp2p-circuit` there was a rift in the IPFS network, were IPFS nodes
 
 ## Table of Contents
 
-- [Install](#install)
-  - [npm](#npm)
-- [Usage](#usage)
-  - [Example](#example)
-  - [This module uses `pull-streams`](#this-module-uses-pull-streams)
-    - [Converting `pull-streams` to Node.js Streams](#converting-pull-streams-to-nodejs-streams)
-- [API](#api)
-- [Contribute](#contribute)
-- [License](#license)
+- [js-libp2p-circuit](#js-libp2p-circuit)
+    - [Why?](#why)
+    - [libp2p-circuit and IPFS](#libp2p-circuit-and-ipfs)
+  - [Table of Contents](#table-of-contents)
+  - [Usage](#usage)
+    - [Example](#example)
+      - [Create dialer/listener](#create-dialerlistener)
+      - [Create `relay`](#create-relay)
+    - [This module uses `pull-streams`](#this-module-uses-pull-streams)
+      - [Converting `pull-streams` to Node.js Streams](#converting-pull-streams-to-nodejs-streams)
+  - [API](#api)
+    - [Implementation rational](#implementation-rational)
 
 ## Usage
 
diff --git a/src/circuit/circuit/dialer.js b/src/circuit/circuit/dialer.js
index 2407c40f..2c250e2c 100644
--- a/src/circuit/circuit/dialer.js
+++ b/src/circuit/circuit/dialer.js
@@ -6,7 +6,7 @@ const waterfall = require('async/waterfall')
 const setImmediate = require('async/setImmediate')
 const multiaddr = require('multiaddr')
 
-const Connection = require('interface-connection').Connection
+const { Connection } = require('libp2p-interfaces/src/connection')
 
 const utilsFactory = require('./utils')
 const StreamHandler = require('./stream-handler')
diff --git a/src/circuit/circuit/stop.js b/src/circuit/circuit/stop.js
index f420c8f6..e18ef028 100644
--- a/src/circuit/circuit/stop.js
+++ b/src/circuit/circuit/stop.js
@@ -3,7 +3,7 @@
 const setImmediate = require('async/setImmediate')
 
 const EE = require('events').EventEmitter
-const Connection = require('interface-connection').Connection
+const { Connection } = require('libp2p-interfaces/src/connection')
 const utilsFactory = require('./utils')
 const PeerInfo = require('peer-info')
 const proto = require('../protocol').CircuitRelay
diff --git a/src/constants.js b/src/constants.js
new file mode 100644
index 00000000..72c442d2
--- /dev/null
+++ b/src/constants.js
@@ -0,0 +1,12 @@
+'use strict'
+
+module.exports = {
+  DENY_TTL: 5 * 60 * 1e3, // How long before an errored peer can be dialed again
+  DENY_ATTEMPTS: 5, // Num of unsuccessful dials before a peer is permanently denied
+  DIAL_TIMEOUT: 30e3, // How long in ms a dial attempt is allowed to take
+  MAX_COLD_CALLS: 50, // How many dials w/o protocols that can be queued
+  MAX_PARALLEL_DIALS: 100, // Maximum allowed concurrent dials
+  QUARTER_HOUR: 15 * 60e3,
+  PRIORITY_HIGH: 10,
+  PRIORITY_LOW: 20
+}
diff --git a/src/dialer.js b/src/dialer.js
new file mode 100644
index 00000000..2177ccda
--- /dev/null
+++ b/src/dialer.js
@@ -0,0 +1,98 @@
+'use strict'
+
+const multiaddr = require('multiaddr')
+const errCode = require('err-code')
+const { default: PQueue } = require('p-queue')
+const AbortController = require('abort-controller')
+const debug = require('debug')
+const log = debug('libp2p:dialer')
+log.error = debug('libp2p:dialer:error')
+
+const { codes } = require('./errors')
+const {
+  MAX_PARALLEL_DIALS,
+  DIAL_TIMEOUT
+} = require('./constants')
+
+class Dialer {
+  /**
+   * @constructor
+   * @param {object} options
+   * @param {TransportManager} options.transportManager
+   * @param {number} options.concurrency Number of max concurrent dials. Defaults to `MAX_PARALLEL_DIALS`
+   * @param {number} options.timeout How long a dial attempt is allowed to take. Defaults to `DIAL_TIMEOUT`
+   */
+  constructor ({
+    transportManager,
+    concurrency = MAX_PARALLEL_DIALS,
+    timeout = DIAL_TIMEOUT
+  }) {
+    this.transportManager = transportManager
+    this.concurrency = concurrency
+    this.timeout = timeout
+    this.queue = new PQueue({ concurrency, timeout, throwOnTimeout: true })
+  }
+
+  /**
+   * Connects to a given `Multiaddr`. `addr` should include the id of the peer being
+   * dialed, it will be used for encryption verification.
+   *
+   * @async
+   * @param {Multiaddr} addr The address to dial
+   * @param {object} [options]
+   * @param {AbortSignal} [options.signal] An AbortController signal
+   * @returns {Promise<Connection>}
+   */
+  async connectToMultiaddr (addr, options = {}) {
+    addr = multiaddr(addr)
+    let conn
+    let controller
+
+    if (!options.signal) {
+      controller = new AbortController()
+      options.signal = controller.signal
+    }
+
+    try {
+      conn = await this.queue.add(() => this.transportManager.dial(addr, options))
+    } catch (err) {
+      if (err.name === 'TimeoutError') {
+        controller.abort()
+        err.code = codes.ERR_TIMEOUT
+      }
+      log.error('Error dialing address %s,', addr, err)
+      throw err
+    }
+
+    return conn
+  }
+
+  /**
+   * Connects to a given `PeerInfo` by dialing all of its known addresses.
+   * The dial to the first address that is successfully able to upgrade a connection
+   * will be used.
+   *
+   * @async
+   * @param {PeerInfo} peerInfo The remote peer to dial
+   * @param {object} [options]
+   * @param {AbortSignal} [options.signal] An AbortController signal
+   * @returns {Promise<Connection>}
+   */
+  async connectToPeer (peerInfo, options = {}) {
+    const addrs = peerInfo.multiaddrs.toArray()
+    for (const addr of addrs) {
+      try {
+        return await this.connectToMultiaddr(addr, options)
+      } catch (_) {
+        // The error is already logged, just move to the next addr
+        continue
+      }
+    }
+
+    const err = errCode(new Error('Could not dial peer, all addresses failed'), codes.ERR_CONNECTION_FAILED)
+    log.error(err)
+    throw err
+  }
+}
+
+module.exports = Dialer
diff --git a/src/errors.js b/src/errors.js
index 5219891a..de75f094 100644
--- a/src/errors.js
+++ b/src/errors.js
@@ -8,10 +8,16 @@ exports.messages = {
 exports.codes = {
   DHT_DISABLED: 'ERR_DHT_DISABLED',
   PUBSUB_NOT_STARTED: 'ERR_PUBSUB_NOT_STARTED',
+  ERR_CONNECTION_FAILED: 'ERR_CONNECTION_FAILED',
   ERR_NODE_NOT_STARTED: 'ERR_NODE_NOT_STARTED',
   ERR_NO_VALID_ADDRESSES: 'ERR_NO_VALID_ADDRESSES',
   ERR_DISCOVERED_SELF: 'ERR_DISCOVERED_SELF',
   ERR_DUPLICATE_TRANSPORT: 'ERR_DUPLICATE_TRANSPORT',
+  ERR_ENCRYPTION_FAILED: 'ERR_ENCRYPTION_FAILED',
   ERR_INVALID_KEY: 'ERR_INVALID_KEY',
-  ERR_TRANSPORT_UNAVAILABLE: 'ERR_TRANSPORT_UNAVAILABLE'
+  ERR_MUXER_UNAVAILABLE: 'ERR_MUXER_UNAVAILABLE',
+  ERR_TIMEOUT: 'ERR_TIMEOUT',
+  ERR_TRANSPORT_UNAVAILABLE: 'ERR_TRANSPORT_UNAVAILABLE',
+  ERR_TRANSPORT_DIAL_FAILED: 'ERR_TRANSPORT_DIAL_FAILED',
+  ERR_UNSUPPORTED_PROTOCOL: 'ERR_UNSUPPORTED_PROTOCOL'
 }
diff --git a/src/index.js b/src/index.js
index b973739b..3d5cf8c2 100644
--- a/src/index.js
+++ b/src/index.js
@@ -13,20 +13,22 @@ const nextTick = require('async/nextTick')
 
 const PeerBook = require('peer-book')
 const PeerInfo = require('peer-info')
+const multiaddr = require('multiaddr')
 const Switch = require('./switch')
 const Ping = require('./ping')
-const ConnectionManager = require('./connection-manager')
 
 const { emitFirst } = require('./util')
 const peerRouting = require('./peer-routing')
 const contentRouting = require('./content-routing')
 const dht = require('./dht')
 const pubsub = require('./pubsub')
-const { getPeerInfoRemote } = require('./get-peer-info')
-const validateConfig = require('./config').validate
+const { getPeerInfo, getPeerInfoRemote } = require('./get-peer-info')
+const { validate: validateConfig } = require('./config')
 const { codes } = require('./errors')
 
+const Dialer = require('./dialer')
 const TransportManager = require('./transport-manager')
+const Upgrader = require('./upgrader')
 
 const notStarted = (action, state) => {
   return errCode(
@@ -61,64 +63,49 @@ class Libp2p extends EventEmitter {
 
     // create the switch, and listen for errors
     this._switch = new Switch(this.peerInfo, this.peerBook, this._options.switch)
-    this._switch.on('error', (...args) => this.emit('error', ...args))
 
-    this.stats = this._switch.stats
-    this.connectionManager = new ConnectionManager(this, this._options.connectionManager)
+    // Setup the Upgrader
+    this.upgrader = new Upgrader({
+      localPeer: this.peerInfo.id,
+      onConnection: (connection) => {
+        const peerInfo = getPeerInfo(connection.remotePeer)
+        this.emit('peer:connect', peerInfo)
+      },
+      onConnectionEnd: (connection) => {
+        const peerInfo = getPeerInfo(connection.remotePeer)
+        this.emit('peer:disconnect', peerInfo)
+      }
+    })
 
     // Setup the transport manager
     this.transportManager = new TransportManager({
       libp2p: this,
-      // TODO: set the actual upgrader
-      upgrader: {
-        upgradeInbound: (maConn) => maConn,
-        upgradeOutbound: (maConn) => maConn
-      },
-      // TODO: Route incoming connections to a multiplex protocol router
-      onConnection: () => {}
+      upgrader: this.upgrader
     })
     this._modules.transport.forEach((Transport) => {
       this.transportManager.add(Transport.prototype[Symbol.toStringTag], Transport)
     })
 
-    // Attach stream multiplexers
-    if (this._modules.streamMuxer) {
-      const muxers = this._modules.streamMuxer
-      muxers.forEach((muxer) => this._switch.connection.addStreamMuxer(muxer))
-
-      // If muxer exists
-      //   we can use Identify
-      this._switch.connection.reuse()
-      //   we can use Relay for listening/dialing
-      this._switch.connection.enableCircuitRelay(this._config.relay)
-
-      // Received incomming dial and muxer upgrade happened,
-      // reuse this muxed connection
-      this._switch.on('peer-mux-established', (peerInfo) => {
-        this.emit('peer:connect', peerInfo)
-      })
-
-      this._switch.on('peer-mux-closed', (peerInfo) => {
-        this.emit('peer:disconnect', peerInfo)
-      })
-    }
-
-    // Events for anytime connections are created/removed
-    this._switch.on('connection:start', (peerInfo) => {
-      this.emit('connection:start', peerInfo)
-    })
-    this._switch.on('connection:end', (peerInfo) => {
-      this.emit('connection:end', peerInfo)
-    })
-
     // Attach crypto channels
     if (this._modules.connEncryption) {
       const cryptos = this._modules.connEncryption
       cryptos.forEach((crypto) => {
-        this._switch.connection.crypto(crypto.tag, crypto.encrypt)
+        this.upgrader.cryptos.set(crypto.tag, crypto)
       })
     }
 
+    // Attach stream multiplexers
+    if (this._modules.streamMuxer) {
+      const muxers = this._modules.streamMuxer
+      muxers.forEach((muxer) => {
+        this.upgrader.muxers.set(muxer.multicodec, muxer)
+      })
+    }
+
+    this.dialer = new Dialer({
+      transportManager: this.transportManager
+    })
+
     // Attach private network protector
     if (this._modules.connProtector) {
       this._switch.protector = this._modules.connProtector
@@ -153,7 +140,8 @@ class Libp2p extends EventEmitter {
     this.state = new FSM('STOPPED', {
       STOPPED: {
         start: 'STARTING',
-        stop: 'STOPPED'
+        stop: 'STOPPED',
+        done: 'STOPPED'
       },
       STARTING: {
         done: 'STARTED',
@@ -175,7 +163,6 @@ class Libp2p extends EventEmitter {
     })
     this.state.on('STOPPING', () => {
       log('libp2p is stopping')
-      this._onStopping()
     })
     this.state.on('STARTED', () => {
       log('libp2p has started')
@@ -201,7 +188,7 @@ class Libp2p extends EventEmitter {
     this._peerDiscovered = this._peerDiscovered.bind(this)
 
     // promisify all instance methods
-    ;['start', 'stop', 'dial', 'dialProtocol', 'dialFSM', 'hangUp', 'ping'].forEach(method => {
+    ;['start', 'hangUp', 'ping'].forEach(method => {
       this[method] = promisify(this[method], { context: this })
     })
   }
@@ -234,13 +221,21 @@ class Libp2p extends EventEmitter {
 
   /**
    * Stop the libp2p node by closing its listeners and open connections
-   *
-   * @param {function(Error)} callback
+   * @async
    * @returns {void}
    */
-  stop (callback = () => {}) {
-    emitFirst(this, ['error', 'stop'], callback)
+  async stop () {
     this.state('stop')
+
+    try {
+      await this.transportManager.close()
+    } catch (err) {
+      if (err) {
+        log.error(err)
+        this.emit('error', err)
+      }
+    }
+    this.state('done')
   }
 
   isStarted () {
@@ -252,11 +247,12 @@ class Libp2p extends EventEmitter {
    * peer will be added to the nodes `PeerBook`
    *
    * @param {PeerInfo|PeerId|Multiaddr|string} peer The peer to dial
-   * @param {function(Error)} callback
-   * @returns {void}
+   * @param {object} options
+   * @param {AbortSignal} [options.signal]
+   * @returns {Promise<Connection>}
    */
-  dial (peer, callback) {
-    this.dialProtocol(peer, null, callback)
+  dial (peer, options) {
+    return this.dialProtocol(peer, null, options)
   }
 
   /**
@@ -264,50 +260,28 @@ class Libp2p extends EventEmitter {
    * If successful, the `PeerInfo` of the peer will be added to the nodes `PeerBook`,
    * and the `Connection` will be sent in the callback
    *
+   * @async
    * @param {PeerInfo|PeerId|Multiaddr|string} peer The peer to dial
-   * @param {string} protocol
-   * @param {function(Error, Connection)} callback
-   * @returns {void}
+   * @param {string[]|string} protocols
+   * @param {object} options
+   * @param {AbortSignal} [options.signal]
+   * @returns {Promise<Connection|*>}
    */
-  dialProtocol (peer, protocol, callback) {
-    if (!this.isStarted()) {
-      return callback(notStarted('dial', this.state._state))
+  async dialProtocol (peer, protocols, options) {
+    let connection
+    if (multiaddr.isMultiaddr(peer)) {
+      connection = await this.dialer.connectToMultiaddr(peer, options)
+    } else {
+      peer = await getPeerInfoRemote(peer, this)
+      connection = await this.dialer.connectToPeer(peer, options)
     }
 
-    if (typeof protocol === 'function') {
-      callback = protocol
-      protocol = undefined
+    // If a protocol was provided, create a new stream
+    if (protocols) {
+      return connection.newStream(protocols)
     }
 
-    getPeerInfoRemote(peer, this)
-      .then(peerInfo => {
-        this._switch.dial(peerInfo, protocol, callback)
-      }, callback)
-  }
-
-  /**
-   * Similar to `dial` and `dialProtocol`, but the callback will contain a
-   * Connection State Machine.
-   *
-   * @param {PeerInfo|PeerId|Multiaddr|string} peer The peer to dial
-   * @param {string} protocol
-   * @param {function(Error, ConnectionFSM)} callback
-   * @returns {void}
-   */
-  dialFSM (peer, protocol, callback) {
-    if (!this.isStarted()) {
-      return callback(notStarted('dial', this.state._state))
-    }
-
-    if (typeof protocol === 'function') {
-      callback = protocol
-      protocol = undefined
-    }
-
-    getPeerInfoRemote(peer, this)
-      .then(peerInfo => {
-        this._switch.dialFSM(peerInfo, protocol, callback)
-      }, callback)
+    return connection
   }
 
   /**
@@ -342,12 +316,28 @@ class Libp2p extends EventEmitter {
       }, callback)
   }
 
-  handle (protocol, handlerFunc, matchFunc) {
-    this._switch.handle(protocol, handlerFunc, matchFunc)
+  /**
+   * Registers the `handler` for each protocol
+   * @param {string[]|string} protocols
+   * @param {function({ stream:*, protocol:string })} handler
+   */
+  handle (protocols, handler) {
+    protocols = Array.isArray(protocols) ? protocols : [protocols]
+    protocols.forEach(protocol => {
+      this.upgrader.protocols.set(protocol, handler)
+    })
   }
 
-  unhandle (protocol) {
-    this._switch.unhandle(protocol)
+  /**
+   * Removes the handler for each protocol. The protocol
+   * will no longer be supported on streams.
+   * @param {string[]|string} protocols
+   */
+  unhandle (protocols) {
+    protocols = Array.isArray(protocols) ? protocols : [protocols]
+    protocols.forEach(protocol => {
+      this.upgrader.protocols.delete(protocol)
+    })
   }
 
   async _onStarting () {
@@ -373,21 +363,6 @@ class Libp2p extends EventEmitter {
     this.state('done')
   }
 
-  async _onStopping () {
-    // Start parallel tasks
-    try {
-      await this.transportManager.close()
-    } catch (err) {
-      if (err) {
-        log.error(err)
-        this.emit('error', err)
-      }
-    }
-
-    // libp2p has stopped
-    this.state('done')
-  }
-
   /**
    * Handles discovered peers. Each discovered peer will be emitted via
    * the `peer:discovery` event. If auto dial is enabled for libp2p
diff --git a/src/pnet/index.js b/src/pnet/index.js
index a6480dca..db79e3bc 100644
--- a/src/pnet/index.js
+++ b/src/pnet/index.js
@@ -1,7 +1,7 @@
 'use strict'
 
 const pull = require('pull-stream')
-const Connection = require('interface-connection').Connection
+const { Connection } = require('libp2p-interfaces/src/connection')
 const assert = require('assert')
 
 const Errors = require('./errors')
diff --git a/src/switch/README.md b/src/switch/README.md
index 2ceec4bb..3ca9e9d5 100644
--- a/src/switch/README.md
+++ b/src/switch/README.md
@@ -81,7 +81,7 @@ tests]([./test/pnet.node.js]).
 
 ##### `switch.connection.addUpgrade()`
 
-A connection upgrade must be able to receive and return something that implements the [interface-connection](https://github.com/libp2p/interface-connection) specification.
+A connection upgrade must be able to receive and return something that implements the [interface-connection](https://github.com/libp2p/js-interfaces/tree/master/src/connection) specification.
 
 > **WIP**
 
@@ -151,7 +151,7 @@ a low priority dial to the provided peer. Calls to `dial` and `dialFSM` will tak
 - `error`:  emitted whenever a fatal error occurs with the connection; the error will be emitted.
 - `error:upgrade_failed`: emitted whenever the connection fails to upgrade with a muxer, this is not fatal.
 - `error:connection_attempt_failed`: emitted whenever a dial attempt fails for a given transport. An array of errors is emitted.
-- `connection`: emitted whenever a useable connection has been established; the underlying [Connection](https://github.com/libp2p/interface-connection) will be emitted.
+- `connection`: emitted whenever a useable connection has been established; the underlying [Connection](https://github.com/libp2p/js-interfaces/tree/master/src/connection) will be emitted.
 - `close`: emitted when the connection has closed.
 
 ### `switch.handle(protocol, handlerFunc, matchFunc)`
@@ -365,7 +365,7 @@ In order for a transport to be supported, it has to follow the [interface-transp
 
 ### Connection upgrades
 
-Each connection in libp2p follows the [interface-connection](https://github.com/libp2p/interface-connection) spec. This design decision enables libp2p to have upgradable transports.
+Each connection in libp2p follows the [interface-connection](https://github.com/libp2p/js-interfaces/tree/master/src/connection) spec. This design decision enables libp2p to have upgradable transports.
 
 We think of `upgrade` as a very important notion when we are talking about connections, we can see mechanisms like: stream multiplexing, congestion control, encrypted channels, multipath, simulcast, etc, as `upgrades` to a connection. A connection can be a simple and with no guarantees, drop a packet on the network with a destination thing, a transport in the other hand can be a connection and or a set of different upgrades that are mounted on top of each other, giving extra functionality to that connection and therefore `upgrading` it.
 
diff --git a/src/switch/limit-dialer/queue.js b/src/switch/limit-dialer/queue.js
index 344997ad..94d38c5b 100644
--- a/src/switch/limit-dialer/queue.js
+++ b/src/switch/limit-dialer/queue.js
@@ -1,6 +1,6 @@
 'use strict'
 
-const Connection = require('interface-connection').Connection
+const { Connection } = require('libp2p-interfaces/src/connection')
 const pull = require('pull-stream/pull')
 const empty = require('pull-stream/sources/empty')
 const timeout = require('async/timeout')
diff --git a/src/switch/observe-connection.js b/src/switch/observe-connection.js
index c6e928c0..45f87cd0 100644
--- a/src/switch/observe-connection.js
+++ b/src/switch/observe-connection.js
@@ -1,6 +1,6 @@
 'use strict'
 
-const Connection = require('interface-connection').Connection
+const { Connection } = require('libp2p-interfaces/src/connection')
 const pull = require('pull-stream/pull')
 
 /**
diff --git a/src/transport-manager.js b/src/transport-manager.js
index 371f2f57..136dc8c8 100644
--- a/src/transport-manager.js
+++ b/src/transport-manager.js
@@ -13,14 +13,12 @@ class TransportManager {
    * @param {object} options
    * @param {Libp2p} options.libp2p The Libp2p instance. It will be passed to the transports.
    * @param {Upgrader} options.upgrader The upgrader to provide to the transports
-   * @param {function(Connection)} options.onConnection Called whenever an incoming connection is received
    */
-  constructor ({ libp2p, upgrader, onConnection }) {
+  constructor ({ libp2p, upgrader }) {
     this.libp2p = libp2p
     this.upgrader = upgrader
     this._transports = new Map()
     this._listeners = new Map()
-    this.onConnection = onConnection
   }
 
   /**
@@ -45,7 +43,9 @@ class TransportManager {
     })
 
     this._transports.set(key, transport)
-    this._listeners.set(key, [])
+    if (!this._listeners.has(key)) {
+      this._listeners.set(key, [])
+    }
   }
 
   /**
@@ -57,11 +57,13 @@ class TransportManager {
     for (const [key, listeners] of this._listeners) {
       log('closing listeners for %s', key)
       while (listeners.length) {
-        tasks.push(listeners.pop().close())
+        const listener = listeners.pop()
+        tasks.push(listener.close())
       }
     }
 
     await Promise.all(tasks)
+    log('all listeners closed')
     this._listeners.clear()
   }
 
@@ -76,8 +78,12 @@ class TransportManager {
     if (!transport) {
       throw errCode(new Error(`No transport available for address ${String(ma)}`), codes.ERR_TRANSPORT_UNAVAILABLE)
     }
-    const conn = await transport.dial(ma, options)
-    return conn
+
+    try {
+      return await transport.dial(ma, options)
+    } catch (err) {
+      throw errCode(new Error('Transport dial failed'), codes.ERR_TRANSPORT_DIAL_FAILED, err)
+    }
   }
 
   /**
diff --git a/src/upgrader.js b/src/upgrader.js
new file mode 100644
index 00000000..e470d81c
--- /dev/null
+++ b/src/upgrader.js
@@ -0,0 +1,336 @@
+'use strict'
+
+const debug = require('debug')
+const log = debug('libp2p:upgrader')
+log.error = debug('libp2p:upgrader:error')
+const Multistream = require('multistream-select')
+const { Connection } = require('libp2p-interfaces/src/connection')
+const PeerId = require('peer-id')
+const pipe = require('it-pipe')
+const errCode = require('err-code')
+
+const { codes } = require('./errors')
+
+/**
+ * @typedef MultiaddrConnection
+ * @property {function} sink
+ * @property {AsyncIterator} source
+ * @property {*} conn
+ * @property {Multiaddr} remoteAddr
+ */
+
+/**
+ * @typedef CryptoResult
+ * @property {*} conn A duplex iterable
+ * @property {PeerId} remotePeer
+ * @property {string} protocol
+ */
+
+class Upgrader {
+  /**
+   * @param {object} options
+   * @param {PeerId} options.localPeer
+   * @param {Map<string, Crypto>} options.cryptos
+   * @param {Map<string, Muxer>} options.muxers
+   */
+  constructor ({ localPeer, cryptos, muxers, onConnectionEnd = () => {}, onConnection = () => {} }) {
+    this.localPeer = localPeer
+    this.cryptos = cryptos || new Map()
+    this.muxers = muxers || new Map()
+    this.protocols = new Map()
+    this.onConnection = onConnection
+    this.onConnectionEnd = onConnectionEnd
+  }
+
+  /**
+   * Upgrades an inbound connection
+   * @async
+   * @param {MultiaddrConnection} maConn
+   * @returns {Promise<Connection>}
+   */
+  async upgradeInbound (maConn) {
+    let encryptedConn
+    let remotePeer
+    let muxedConnection
+    let Muxer
+    let cryptoProtocol
+
+    try {
+      // Encrypt the connection
+      ({
+        conn: encryptedConn,
+        remotePeer,
+        protocol: cryptoProtocol
+      } = await this._encryptInbound(this.localPeer, maConn, this.cryptos))
+
+      // Multiplex the connection
+      ;({ stream: muxedConnection, Muxer } = await this._multiplexInbound(encryptedConn, this.muxers))
+    } catch (err) {
+      log.error('Failed to upgrade inbound connection', err)
+      await maConn.close(err)
+      // TODO: We shouldn't throw here, as there isn't anything to catch the failure
+      throw err
+    }
+
+    log('Successfully upgraded inbound connection')
+
+    return this._createConnection({
+      cryptoProtocol,
+      direction: 'inbound',
+      maConn,
+      muxedConnection,
+      Muxer,
+      remotePeer
+    })
+  }
+
+  /**
+   * Upgrades an outbound connection
+   * @async
+   * @param {MultiaddrConnection} maConn
+   * @returns {Promise<Connection>}
+   */
+  async upgradeOutbound (maConn) {
+    let remotePeerId
+    try {
+      remotePeerId = PeerId.createFromB58String(maConn.remoteAddr.getPeerId())
+    } catch (err) {
+      log.error('multiaddr did not contain a valid peer id', err)
+    }
+
+    let encryptedConn
+    let remotePeer
+    let muxedConnection
+    let cryptoProtocol
+    let Muxer
+
+    try {
+      // Encrypt the connection
+      ({
+        conn: encryptedConn,
+        remotePeer,
+        protocol: cryptoProtocol
+      } = await this._encryptOutbound(this.localPeer, maConn, remotePeerId, this.cryptos))
+
+      // Multiplex the connection
+      ;({ stream: muxedConnection, Muxer } = await this._multiplexOutbound(encryptedConn, this.muxers))
+    } catch (err) {
+      log.error('Failed to upgrade outbound connection', err)
+      await maConn.close(err)
+      throw err
+    }
+
+    log('Successfully upgraded outbound connection')
+
+    return this._createConnection({
+      cryptoProtocol,
+      direction: 'outbound',
+      maConn,
+      muxedConnection,
+      Muxer,
+      remotePeer
+    })
+  }
+
+  /**
+   * A convenience method for generating a new `Connection`
+   * @private
+   * @param {object} options
+   * @param {string} cryptoProtocol The crypto protocol that was negotiated
+   * @param {string} direction One of ['inbound', 'outbound']
+   * @param {MultiaddrConnection} maConn The transport layer connection
+   * @param {*} muxedConnection A duplex connection returned from multiplexer selection
+   * @param {Muxer} Muxer The muxer to be used for muxing
+   * @param {PeerId} remotePeer The peer the connection is with
+   * @returns {Connection}
+   */
+  _createConnection ({
+    cryptoProtocol,
+    direction,
+    maConn,
+    muxedConnection,
+    Muxer,
+    remotePeer
+  }) {
+    // Create the muxer
+    const muxer = new Muxer({
+      // Run anytime a remote stream is created
+      onStream: async muxedStream => {
+        const mss = new Multistream.Listener(muxedStream)
+        const { stream, protocol } = await mss.handle(Array.from(this.protocols.keys()))
+        log('%s: incoming stream opened on %s', direction, protocol)
+        connection.addStream(stream, protocol)
+        this._onStream({ stream, protocol })
+      },
+      // Run anytime a stream closes
+      onStreamEnd: muxedStream => {
+        connection.removeStream(muxedStream.id)
+      }
+    })
+
+    const newStream = async protocols => {
+      log('%s: starting new stream on %s', direction, protocols)
+      const muxedStream = muxer.newStream()
+      const mss = new Multistream.Dialer(muxedStream)
+      try {
+        const { stream, protocol } = await mss.select(protocols)
+        return { stream: { ...muxedStream, ...stream }, protocol }
+      } catch (err) {
+        log.error('could not create new stream', err)
+        throw errCode(err, codes.ERR_UNSUPPORTED_PROTOCOL)
+      }
+    }
+
+    // Pipe all data through the muxer
+    pipe(muxedConnection, muxer, muxedConnection)
+
+    maConn.timeline.upgraded = Date.now()
+    const timelineProxy = new Proxy(maConn.timeline, {
+      set: (...args) => {
+        if (args[1] === 'close' && args[2]) {
+          this.onConnectionEnd(connection)
+        }
+
+        return Reflect.set(...args)
+      }
+    })
+
+    // Create the connection
+    const connection = new Connection({
+      localAddr: maConn.localAddr,
+      remoteAddr: maConn.remoteAddr,
+      localPeer: this.localPeer,
+      remotePeer: remotePeer,
+      stat: {
+        direction,
+        timeline: timelineProxy,
+        multiplexer: Muxer.multicodec,
+        encryption: cryptoProtocol
+      },
+      newStream,
+      getStreams: () => muxer.streams,
+      close: err => maConn.close(err)
+    })
+
+    this.onConnection(connection)
+
+    return connection
+  }
+
+  /**
+   * Routes incoming streams to the correct handler
+   * @private
+   * @param {object} options
+   * @param {Stream} options.stream
+   * @param {string} protocol
+   */
+  _onStream ({ stream, protocol }) {
+    const handler = this.protocols.get(protocol)
+    handler({ stream, protocol })
+  }
+
+  /**
+   * Attempts to encrypt the incoming `connection` with the provided `cryptos`.
+   * @private
+   * @async
+   * @param {PeerId} localPeer The initiators PeerInfo
+   * @param {*} connection
+   * @param {Map<string, Crypto>} cryptos
+   * @returns {CryptoResult} An encrypted connection, remote peer `PeerId` and the protocol of the `Crypto` used
+   */
+  async _encryptInbound (localPeer, connection, cryptos) {
+    const mss = new Multistream.Listener(connection)
+    const protocols = Array.from(cryptos.keys())
+    log('selecting inbound crypto protocol', protocols)
+
+    try {
+      const { stream, protocol } = await mss.handle(protocols)
+      const crypto = cryptos.get(protocol)
+      log('encrypting inbound connection...')
+
+      return {
+        ...await crypto.secureInbound(localPeer, stream),
+        protocol
+      }
+    } catch (err) {
+      throw errCode(err, codes.ERR_ENCRYPTION_FAILED)
+    }
+  }
+
+  /**
+   * Attempts to encrypt the given `connection` with the provided `cryptos`.
+   * The first `Crypto` module to succeed will be used
+   * @private
+   * @async
+   * @param {PeerId} localPeer The initiators PeerInfo
+   * @param {*} connection
+   * @param {PeerId} remotePeerId
+   * @param {Map<string, Crypto>} cryptos
+   * @returns {CryptoResult} An encrypted connection, remote peer `PeerId` and the protocol of the `Crypto` used
+   */
+  async _encryptOutbound (localPeer, connection, remotePeerId, cryptos) {
+    const mss = new Multistream.Dialer(connection)
+    const protocols = Array.from(cryptos.keys())
+    log('selecting outbound crypto protocol', protocols)
+
+    try {
+      const { stream, protocol } = await mss.select(protocols)
+      const crypto = cryptos.get(protocol)
+      log('encrypting outbound connection to %j', remotePeerId)
+
+      return {
+        ...await crypto.secureOutbound(localPeer, stream, remotePeerId),
+        protocol
+      }
+    } catch (err) {
+      throw errCode(err, codes.ERR_ENCRYPTION_FAILED)
+    }
+  }
+
+  /**
+   * Selects one of the given muxers via multistream-select. That
+   * muxer will be used for all future streams on the connection.
+   * @private
+   * @async
+   * @param {*} connection A basic duplex connection to multiplex
+   * @param {Map<string, Muxer>} muxers The muxers to attempt multiplexing with
+   * @returns {*} A muxed connection
+   */
+  async _multiplexOutbound (connection, muxers) {
+    const dialer = new Multistream.Dialer(connection)
+    const protocols = Array.from(muxers.keys())
+    log('outbound selecting muxer %s', protocols)
+    try {
+      const { stream, protocol } = await dialer.select(protocols)
+      log('%s selected as muxer protocol', protocol)
+      const Muxer = muxers.get(protocol)
+      return { stream, Muxer }
+    } catch (err) {
+      throw errCode(err, codes.ERR_MUXER_UNAVAILABLE)
+    }
+  }
+
+  /**
+   * Registers support for one of the given muxers via multistream-select. The
+   * selected muxer will be used for all future streams on the connection.
+   * @private
+   * @async
+   * @param {*} connection A basic duplex connection to multiplex
+   * @param {Map<string, Muxer>} muxers The muxers to attempt multiplexing with
+   * @returns {*} A muxed connection
+   */
+  async _multiplexInbound (connection, muxers) {
+    const listener = new Multistream.Listener(connection)
+    const protocols = Array.from(muxers.keys())
+    log('inbound handling muxers %s', protocols)
+    try {
+      const { stream, protocol } = await listener.handle(protocols)
+      const Muxer = muxers.get(protocol)
+      return { stream, Muxer }
+    } catch (err) {
+      throw errCode(err, codes.ERR_MUXER_UNAVAILABLE)
+    }
+  }
+}
+
+module.exports = Upgrader
diff --git a/test/dialing/direct.node.js b/test/dialing/direct.node.js
new file mode 100644
index 00000000..071ad900
--- /dev/null
+++ b/test/dialing/direct.node.js
@@ -0,0 +1,236 @@
+'use strict'
+/* eslint-env mocha */
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const { expect } = chai
+const sinon = require('sinon')
+const Transport = require('libp2p-tcp')
+const Muxer = require('libp2p-mplex')
+const multiaddr = require('multiaddr')
+const PeerId = require('peer-id')
+const PeerInfo = require('peer-info')
+const delay = require('delay')
+const pDefer = require('p-defer')
+const pipe = require('it-pipe')
+
+const Libp2p = require('../../src')
+const Dialer = require('../../src/dialer')
+const TransportManager = require('../../src/transport-manager')
+const { codes: ErrorCodes } = require('../../src/errors')
+
+const mockUpgrader = require('../utils/mockUpgrader')
+const mockCrypto = require('../utils/mockCrypto')
+const Peers = require('../fixtures/peers')
+
+const listenAddr = multiaddr('/ip4/127.0.0.1/tcp/0')
+const unsupportedAddr = multiaddr('/ip4/127.0.0.1/tcp/9999/ws')
+
+describe('Dialing (direct, TCP)', () => {
+  let remoteTM
+  let localTM
+  let remoteAddr
+
+  before(async () => {
+    remoteTM = new TransportManager({
+      libp2p: {},
+      upgrader: mockUpgrader
+    })
+    remoteTM.add(Transport.prototype[Symbol.toStringTag], Transport)
+
+    localTM = new TransportManager({
+      libp2p: {},
+      upgrader: mockUpgrader
+    })
+    localTM.add(Transport.prototype[Symbol.toStringTag], Transport)
+
+    await remoteTM.listen([listenAddr])
+
+    remoteAddr = remoteTM.getAddrs()[0]
+  })
+
+  after(async () => {
+    await remoteTM.close()
+  })
+
+  afterEach(() => {
+    sinon.restore()
+  })
+
+  it('should be able to connect to a remote node via its multiaddr', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+
+    const connection = await dialer.connectToMultiaddr(remoteAddr)
+    expect(connection).to.exist()
+    await connection.close()
+  })
+
+  it('should be able to connect to a remote node via its stringified multiaddr', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+
+    const connection = await dialer.connectToMultiaddr(remoteAddr.toString())
+    expect(connection).to.exist()
+    await connection.close()
+  })
+
+  it('should fail to connect to an unsupported multiaddr', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+
+    try {
+      await dialer.connectToMultiaddr(unsupportedAddr)
+    } catch (err) {
+      expect(err).to.satisfy((err) => err.code === ErrorCodes.ERR_TRANSPORT_UNAVAILABLE)
+      return
+    }
+
+    expect.fail('Dial should have failed')
+  })
+
+  it('should be able to connect to a given peer', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+    const peerId = await PeerId.createFromJSON(Peers[0])
+    const peerInfo = new PeerInfo(peerId)
+    peerInfo.multiaddrs.add(remoteAddr)
+
+    const connection = await dialer.connectToPeer(peerInfo)
+    expect(connection).to.exist()
+    await connection.close()
+  })
+
+  it('should fail to connect to a given peer with unsupported addresses', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+    const peerId = await PeerId.createFromJSON(Peers[0])
+    const peerInfo = new PeerInfo(peerId)
+    peerInfo.multiaddrs.add(unsupportedAddr)
+
+    try {
+      await dialer.connectToPeer(peerInfo)
+    } catch (err) {
+      expect(err).to.satisfy((err) => err.code === ErrorCodes.ERR_CONNECTION_FAILED)
+      return
+    }
+
+    expect.fail('Dial should have failed')
+  })
+
+  it('should abort dials on queue task timeout', async () => {
+    const dialer = new Dialer({
+      transportManager: localTM,
+      timeout: 50
+    })
+    sinon.stub(localTM, 'dial').callsFake(async (addr, options) => {
+      expect(options.signal).to.exist()
+      expect(options.signal.aborted).to.equal(false)
+      expect(addr.toString()).to.eql(remoteAddr.toString())
+      await delay(60)
+      expect(options.signal.aborted).to.equal(true)
+    })
+
+    try {
+      await dialer.connectToMultiaddr(remoteAddr)
+    } catch (err) {
+      expect(err).to.satisfy((err) => err.code === ErrorCodes.ERR_TIMEOUT)
+      return
+    }
+
+    expect.fail('Dial should have failed')
+  })
+
+  it('should dial to the max concurrency', async () => {
+    const dialer = new Dialer({
+      transportManager: localTM,
+      concurrency: 2
+    })
+
+    const deferredDial = pDefer()
+    sinon.stub(localTM, 'dial').callsFake(async () => {
+      await deferredDial.promise
+    })
+
+    // Add 3 dials
+    Promise.all([
+      dialer.connectToMultiaddr(remoteAddr),
+      dialer.connectToMultiaddr(remoteAddr),
+      dialer.connectToMultiaddr(remoteAddr)
+    ])
+
+    // Let the call stack run
+    await delay(0)
+
+    // We should have 2 in progress, and 1 waiting
+    expect(localTM.dial.callCount).to.equal(2)
+    expect(dialer.queue.pending).to.equal(2)
+    expect(dialer.queue.size).to.equal(1)
+
+    deferredDial.resolve()
+
+    // Let the call stack run
+    await delay(0)
+    // All dials should have executed
+    expect(localTM.dial.callCount).to.equal(3)
+    expect(dialer.queue.pending).to.equal(0)
+    expect(dialer.queue.size).to.equal(0)
+  })
+})
+
+describe('libp2p.dialer', () => {
+  let peerInfo
+  let remotePeerInfo
+  let libp2p
+  let remoteLibp2p
+  let remoteAddr
+
+  before(async () => {
+    const [peerId, remotePeerId] = await Promise.all([
+      PeerId.createFromJSON(Peers[0]),
+      PeerId.createFromJSON(Peers[1])
+    ])
+
+    peerInfo = new PeerInfo(peerId)
+    remotePeerInfo = new PeerInfo(remotePeerId)
+
+    remoteLibp2p = new Libp2p({
+      peerInfo: remotePeerInfo,
+      modules: {
+        transport: [Transport],
+        streamMuxer: [Muxer],
+        connEncryption: [mockCrypto]
+      }
+    })
+    remoteLibp2p.handle('/echo/1.0.0', ({ stream }) => pipe(stream, stream))
+
+    await remoteLibp2p.transportManager.listen([listenAddr])
+    remoteAddr = remoteLibp2p.transportManager.getAddrs()[0]
+  })
+
+  afterEach(async () => {
+    sinon.restore()
+    libp2p && await libp2p.stop()
+    libp2p = null
+  })
+
+  after(async () => {
+    await remoteLibp2p.stop()
+  })
+
+  it('should use the dialer for connecting', async () => {
+    libp2p = new Libp2p({
+      peerInfo,
+      modules: {
+        transport: [Transport],
+        streamMuxer: [Muxer],
+        connEncryption: [mockCrypto]
+      }
+    })
+
+    sinon.spy(libp2p.dialer, 'connectToMultiaddr')
+
+    const connection = await libp2p.dial(remoteAddr)
+    expect(connection).to.exist()
+    const { stream, protocol } = await connection.newStream('/echo/1.0.0')
+    expect(stream).to.exist()
+    expect(protocol).to.equal('/echo/1.0.0')
+    await connection.close()
+    expect(libp2p.dialer.connectToMultiaddr.callCount).to.equal(1)
+  })
+})
diff --git a/test/dialing/direct.spec.js b/test/dialing/direct.spec.js
new file mode 100644
index 00000000..bfc77b4d
--- /dev/null
+++ b/test/dialing/direct.spec.js
@@ -0,0 +1,211 @@
+'use strict'
+/* eslint-env mocha */
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const { expect } = chai
+const sinon = require('sinon')
+const pDefer = require('p-defer')
+const delay = require('delay')
+const Transport = require('libp2p-websockets')
+const Muxer = require('libp2p-mplex')
+const multiaddr = require('multiaddr')
+const PeerId = require('peer-id')
+const PeerInfo = require('peer-info')
+
+const { codes: ErrorCodes } = require('../../src/errors')
+const Constants = require('../../src/constants')
+const Dialer = require('../../src/dialer')
+const TransportManager = require('../../src/transport-manager')
+const Libp2p = require('../../src')
+
+const Peers = require('../fixtures/peers')
+const { MULTIADDRS_WEBSOCKETS } = require('../fixtures/browser')
+const mockUpgrader = require('../utils/mockUpgrader')
+const mockCrypto = require('../utils/mockCrypto')
+const unsupportedAddr = multiaddr('/ip4/127.0.0.1/tcp/9999/ws')
+const remoteAddr = MULTIADDRS_WEBSOCKETS[0]
+
+describe('Dialing (direct, WebSockets)', () => {
+  let localTM
+
+  before(() => {
+    localTM = new TransportManager({
+      libp2p: {},
+      upgrader: mockUpgrader,
+      onConnection: () => {}
+    })
+    localTM.add(Transport.prototype[Symbol.toStringTag], Transport)
+  })
+
+  afterEach(() => {
+    sinon.restore()
+  })
+
+  it('should have appropriate defaults', () => {
+    const dialer = new Dialer({ transportManager: localTM })
+    expect(dialer.concurrency).to.equal(Constants.MAX_PARALLEL_DIALS)
+    expect(dialer.timeout).to.equal(Constants.DIAL_TIMEOUT)
+  })
+
+  it('should be able to connect to a remote node via its multiaddr', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+
+    const connection = await dialer.connectToMultiaddr(remoteAddr)
+    expect(connection).to.exist()
+    await connection.close()
+  })
+
+  it('should be able to connect to a remote node via its stringified multiaddr', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+
+    const connection = await dialer.connectToMultiaddr(remoteAddr.toString())
+    expect(connection).to.exist()
+    await connection.close()
+  })
+
+  it('should fail to connect to an unsupported multiaddr', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+
+    try {
+      await dialer.connectToMultiaddr(unsupportedAddr)
+    } catch (err) {
+      expect(err).to.satisfy((err) => err.code === ErrorCodes.ERR_TRANSPORT_DIAL_FAILED)
+      return
+    }
+
+    expect.fail('Dial should have failed')
+  })
+
+  it('should be able to connect to a given peer', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+    const peerId = await PeerId.createFromJSON(Peers[0])
+    const peerInfo = new PeerInfo(peerId)
+    peerInfo.multiaddrs.add(remoteAddr)
+
+    const connection = await dialer.connectToPeer(peerInfo)
+    expect(connection).to.exist()
+    await connection.close()
+  })
+
+  it('should fail to connect to a given peer with unsupported addresses', async () => {
+    const dialer = new Dialer({ transportManager: localTM })
+    const peerId = await PeerId.createFromJSON(Peers[0])
+    const peerInfo = new PeerInfo(peerId)
+    peerInfo.multiaddrs.add(unsupportedAddr)
+
+    try {
+      await dialer.connectToPeer(peerInfo)
+    } catch (err) {
+      expect(err).to.satisfy((err) => err.code === ErrorCodes.ERR_CONNECTION_FAILED)
+      return
+    }
+
+    expect.fail('Dial should have failed')
+  })
+
+  it('should abort dials on queue task timeout', async () => {
+    const dialer = new Dialer({
+      transportManager: localTM,
+      timeout: 50
+    })
+    sinon.stub(localTM, 'dial').callsFake(async (addr, options) => {
+      expect(options.signal).to.exist()
+      expect(options.signal.aborted).to.equal(false)
+      expect(addr.toString()).to.eql(remoteAddr.toString())
+      await delay(60)
+      expect(options.signal.aborted).to.equal(true)
+    })
+
+    try {
+      await dialer.connectToMultiaddr(remoteAddr)
+    } catch (err) {
+      expect(err).to.satisfy((err) => err.code === ErrorCodes.ERR_TIMEOUT)
+      return
+    }
+
+    expect.fail('Dial should have failed')
+  })
+
+  it('should dial to the max concurrency', async () => {
+    const dialer = new Dialer({
+      transportManager: localTM,
+      concurrency: 2
+    })
+
+    const deferredDial = pDefer()
+    sinon.stub(localTM, 'dial').callsFake(async () => {
+      await deferredDial.promise
+    })
+
+    // Add 3 dials
+    Promise.all([
+      dialer.connectToMultiaddr(remoteAddr),
+      dialer.connectToMultiaddr(remoteAddr),
+      dialer.connectToMultiaddr(remoteAddr)
+    ])
+
+    // Let the call stack run
+    await delay(0)
+
+    // We should have 2 in progress, and 1 waiting
+    expect(localTM.dial.callCount).to.equal(2)
+    expect(dialer.queue.pending).to.equal(2)
+    expect(dialer.queue.size).to.equal(1)
+
+    deferredDial.resolve()
+
+    // Let the call stack run
+    await delay(0)
+    // All dials should have executed
+    expect(localTM.dial.callCount).to.equal(3)
+    expect(dialer.queue.pending).to.equal(0)
+    expect(dialer.queue.size).to.equal(0)
+  })
+})
+
+describe.skip('libp2p.dialer', () => {
+  let peerInfo
+  let libp2p
+
+  before(async () => {
+    const peerId = await PeerId.createFromJSON(Peers[0])
+    peerInfo = new PeerInfo(peerId)
+  })
+
+  afterEach(async () => {
+    sinon.restore()
+    libp2p && await libp2p.stop()
+    libp2p = null
+  })
+
+  it('should create a dialer', () => {
+    libp2p = new Libp2p({
+      peerInfo,
+      modules: {
+        transport: [Transport],
+        streamMuxer: [Muxer],
+        connEncryption: [mockCrypto]
+      }
+    })
+
+    expect(libp2p.dialer).to.exist()
+    // Ensure the dialer also has the transport manager
+    expect(libp2p.transportManager).to.equal(libp2p.dialer.transportManager)
+  })
+
+  it('should use the dialer for connecting', async () => {
+    libp2p = new Libp2p({
+      peerInfo,
+      modules: {
+        transport: [Transport],
+        streamMuxer: [Muxer],
+        connEncryption: [mockCrypto]
+      }
+    })
+
+    const connection = await libp2p.dialer.connectToMultiaddr(remoteAddr)
+    expect(connection).to.exist()
+    await connection.close()
+  })
+})
diff --git a/test/node.js b/test/node.js
index fa27625f..61887dac 100644
--- a/test/node.js
+++ b/test/node.js
@@ -1,3 +1,14 @@
 'use strict'
 
-require('./transports/transport-manager.node')
+const glob = require('glob')
+const path = require('path')
+
+// Automatically require test files so we don't have to worry about adding new ones
+glob('test/**/*.node.js', function (err, testPaths) {
+  if (err) throw err
+  if (testPaths.length < 1) throw new Error('Could not find any node test files')
+
+  testPaths.forEach(file => {
+    require(path.resolve(file))
+  })
+})
diff --git a/test/upgrading/upgrader.spec.js b/test/upgrading/upgrader.spec.js
new file mode 100644
index 00000000..d0583584
--- /dev/null
+++ b/test/upgrading/upgrader.spec.js
@@ -0,0 +1,370 @@
+'use strict'
+/* eslint-env mocha */
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const { expect } = chai
+const sinon = require('sinon')
+const Muxer = require('libp2p-mplex')
+const multiaddr = require('multiaddr')
+const PeerId = require('peer-id')
+const PeerInfo = require('peer-info')
+const pipe = require('it-pipe')
+const { collect } = require('streaming-iterables')
+const pSettle = require('p-settle')
+const Transport = require('libp2p-websockets')
+
+const Libp2p = require('../../src')
+const Upgrader = require('../../src/upgrader')
+const { codes } = require('../../src/errors')
+
+const mockCrypto = require('../utils/mockCrypto')
+const mockMultiaddrConnPair = require('../utils/mockMultiaddrConn')
+const Peers = require('../fixtures/peers')
+const addrs = [
+  multiaddr('/ip4/127.0.0.1/tcp/0'),
+  multiaddr('/ip4/127.0.0.1/tcp/0')
+]
+
+describe('Upgrader', () => {
+  let localUpgrader
+  let remoteUpgrader
+  let localPeer
+  let remotePeer
+
+  before(async () => {
+    ([
+      localPeer,
+      remotePeer
+    ] = await Promise.all([
+      PeerId.createFromJSON(Peers[0]),
+      PeerId.createFromJSON(Peers[1])
+    ]))
+
+    localUpgrader = new Upgrader({
+      localPeer
+    })
+    remoteUpgrader = new Upgrader({
+      localPeer: remotePeer
+    })
+
+    localUpgrader.protocols.set('/echo/1.0.0', ({ stream }) => pipe(stream, stream))
+    remoteUpgrader.protocols.set('/echo/1.0.0', ({ stream }) => pipe(stream, stream))
+  })
+
+  afterEach(() => {
+    sinon.restore()
+  })
+
+  it('should ignore a missing remote peer id', async () => {
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer })
+
+    const muxers = new Map([[Muxer.multicodec, Muxer]])
+    sinon.stub(localUpgrader, 'muxers').value(muxers)
+    sinon.stub(remoteUpgrader, 'muxers').value(muxers)
+
+    const cryptos = new Map([[mockCrypto.tag, mockCrypto]])
+    sinon.stub(localUpgrader, 'cryptos').value(cryptos)
+    sinon.stub(remoteUpgrader, 'cryptos').value(cryptos)
+
+    // Remove the peer id from the remote address
+    outbound.remoteAddr = outbound.remoteAddr.decapsulateCode(421)
+
+    const connections = await Promise.all([
+      localUpgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+
+    expect(connections).to.have.length(2)
+  })
+
+  it('should upgrade with valid muxers and crypto', async () => {
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer })
+
+    const muxers = new Map([[Muxer.multicodec, Muxer]])
+    sinon.stub(localUpgrader, 'muxers').value(muxers)
+    sinon.stub(remoteUpgrader, 'muxers').value(muxers)
+
+    const cryptos = new Map([[mockCrypto.tag, mockCrypto]])
+    sinon.stub(localUpgrader, 'cryptos').value(cryptos)
+    sinon.stub(remoteUpgrader, 'cryptos').value(cryptos)
+
+    const connections = await Promise.all([
+      localUpgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+
+    expect(connections).to.have.length(2)
+
+    const { stream, protocol } = await connections[0].newStream('/echo/1.0.0')
+    expect(protocol).to.equal('/echo/1.0.0')
+
+    const hello = Buffer.from('hello there!')
+    const result = await pipe(
+      [hello],
+      stream,
+      function toBuffer (source) {
+        return (async function * () {
+          for await (const val of source) yield val.slice()
+        })()
+      },
+      collect
+    )
+
+    expect(result).to.eql([hello])
+  })
+
+  it('should fail if crypto fails', async () => {
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer })
+
+    const muxers = new Map([[Muxer.multicodec, Muxer]])
+    sinon.stub(localUpgrader, 'muxers').value(muxers)
+    sinon.stub(remoteUpgrader, 'muxers').value(muxers)
+
+    const crypto = {
+      tag: '/insecure',
+      secureInbound: () => { throw new Error('Boom') },
+      secureOutbound: () => { throw new Error('Boom') }
+    }
+
+    const cryptos = new Map([[crypto.tag, crypto]])
+    sinon.stub(localUpgrader, 'cryptos').value(cryptos)
+    sinon.stub(remoteUpgrader, 'cryptos').value(cryptos)
+
+    // Wait for the results of each side of the connection
+    const results = await pSettle([
+      localUpgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+
+    // Ensure both sides fail
+    expect(results).to.have.length(2)
+    results.forEach(result => {
+      expect(result.isRejected).to.equal(true)
+      expect(result.reason.code).to.equal(codes.ERR_ENCRYPTION_FAILED)
+    })
+  })
+
+  it('should fail if muxers do not match', async () => {
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer })
+
+    const muxersLocal = new Map([['/muxer-local', Muxer]])
+    const muxersRemote = new Map([['/muxer-remote', Muxer]])
+    sinon.stub(localUpgrader, 'muxers').value(muxersLocal)
+    sinon.stub(remoteUpgrader, 'muxers').value(muxersRemote)
+
+    const cryptos = new Map([[mockCrypto.tag, mockCrypto]])
+    sinon.stub(localUpgrader, 'cryptos').value(cryptos)
+    sinon.stub(remoteUpgrader, 'cryptos').value(cryptos)
+
+    // Wait for the results of each side of the connection
+    const results = await pSettle([
+      localUpgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+
+    // Ensure both sides fail
+    expect(results).to.have.length(2)
+    results.forEach(result => {
+      expect(result.isRejected).to.equal(true)
+      expect(result.reason.code).to.equal(codes.ERR_MUXER_UNAVAILABLE)
+    })
+  })
+
+  it('should map getStreams and close methods', async () => {
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer })
+
+    const muxers = new Map([[Muxer.multicodec, Muxer]])
+    sinon.stub(localUpgrader, 'muxers').value(muxers)
+    sinon.stub(remoteUpgrader, 'muxers').value(muxers)
+
+    const cryptos = new Map([[mockCrypto.tag, mockCrypto]])
+    sinon.stub(localUpgrader, 'cryptos').value(cryptos)
+    sinon.stub(remoteUpgrader, 'cryptos').value(cryptos)
+
+    const connections = await Promise.all([
+      localUpgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+
+    expect(connections).to.have.length(2)
+
+    // Create a few streams, at least 1 in each direction
+    await connections[0].newStream('/echo/1.0.0')
+    await connections[1].newStream('/echo/1.0.0')
+    await connections[0].newStream('/echo/1.0.0')
+    connections.forEach(conn => {
+      expect(conn.streams).to.have.length(3)
+    })
+
+    // Verify the MultiaddrConnection close method is called
+    sinon.spy(inbound, 'close')
+    sinon.spy(outbound, 'close')
+    await Promise.all(connections.map(conn => conn.close()))
+    expect(inbound.close.callCount).to.equal(1)
+    expect(outbound.close.callCount).to.equal(1)
+  })
+
+  it('should call connection handlers', async () => {
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer })
+
+    const muxers = new Map([[Muxer.multicodec, Muxer]])
+    sinon.stub(localUpgrader, 'muxers').value(muxers)
+    sinon.stub(remoteUpgrader, 'muxers').value(muxers)
+
+    const cryptos = new Map([[mockCrypto.tag, mockCrypto]])
+    sinon.stub(localUpgrader, 'cryptos').value(cryptos)
+    sinon.stub(remoteUpgrader, 'cryptos').value(cryptos)
+
+    // Verify onConnection is called with the connection
+    sinon.spy(localUpgrader, 'onConnection')
+    sinon.spy(remoteUpgrader, 'onConnection')
+    const connections = await Promise.all([
+      localUpgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+    expect(connections).to.have.length(2)
+    expect(localUpgrader.onConnection.callCount).to.equal(1)
+    expect(localUpgrader.onConnection.getCall(0).args).to.eql([connections[0]])
+    expect(remoteUpgrader.onConnection.callCount).to.equal(1)
+    expect(remoteUpgrader.onConnection.getCall(0).args).to.eql([connections[1]])
+
+    // Verify onConnectionEnd is called with the connection
+    sinon.spy(localUpgrader, 'onConnectionEnd')
+    sinon.spy(remoteUpgrader, 'onConnectionEnd')
+    await Promise.all(connections.map(conn => conn.close()))
+    expect(localUpgrader.onConnectionEnd.callCount).to.equal(1)
+    expect(localUpgrader.onConnectionEnd.getCall(0).args).to.eql([connections[0]])
+    expect(remoteUpgrader.onConnectionEnd.callCount).to.equal(1)
+    expect(remoteUpgrader.onConnectionEnd.getCall(0).args).to.eql([connections[1]])
+  })
+
+  it('should fail to create a stream for an unsupported protocol', async () => {
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer })
+
+    const muxers = new Map([[Muxer.multicodec, Muxer]])
+    sinon.stub(localUpgrader, 'muxers').value(muxers)
+    sinon.stub(remoteUpgrader, 'muxers').value(muxers)
+
+    const cryptos = new Map([[mockCrypto.tag, mockCrypto]])
+    sinon.stub(localUpgrader, 'cryptos').value(cryptos)
+    sinon.stub(remoteUpgrader, 'cryptos').value(cryptos)
+
+    const connections = await Promise.all([
+      localUpgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+
+    expect(connections).to.have.length(2)
+
+    const results = await pSettle([
+      connections[0].newStream('/unsupported/1.0.0'),
+      connections[1].newStream('/unsupported/1.0.0')
+    ])
+    expect(results).to.have.length(2)
+    results.forEach(result => {
+      expect(result.isRejected).to.equal(true)
+      expect(result.reason.code).to.equal(codes.ERR_UNSUPPORTED_PROTOCOL)
+    })
+  })
+})
+
+describe('libp2p.upgrader', () => {
+  let peers
+  let libp2p
+
+  before(async () => {
+    const ids = await Promise.all([
+      PeerId.createFromJSON(Peers[0]),
+      PeerId.createFromJSON(Peers[1])
+    ])
+    peers = ids.map(peerId => new PeerInfo(peerId))
+  })
+
+  afterEach(async () => {
+    sinon.restore()
+    libp2p && await libp2p.stop()
+    libp2p = null
+  })
+
+  it('should create an Upgrader', () => {
+    libp2p = new Libp2p({
+      peerInfo: peers[0],
+      modules: {
+        transport: [Transport],
+        streamMuxer: [Muxer],
+        connEncryption: [mockCrypto]
+      }
+    })
+
+    expect(libp2p.upgrader).to.exist()
+    expect(libp2p.upgrader.muxers).to.eql(new Map([[Muxer.multicodec, Muxer]]))
+    expect(libp2p.upgrader.cryptos).to.eql(new Map([[mockCrypto.tag, mockCrypto]]))
+    // Ensure the transport manager also has the upgrader
+    expect(libp2p.upgrader).to.equal(libp2p.transportManager.upgrader)
+  })
+
+  it('should be able to register and unregister a handler', () => {
+    libp2p = new Libp2p({
+      peerInfo: peers[0],
+      modules: {
+        transport: [Transport],
+        streamMuxer: [Muxer],
+        connEncryption: [mockCrypto]
+      }
+    })
+
+    expect(libp2p.upgrader.protocols.size).to.equal(0)
+
+    const echoHandler = () => {}
+    libp2p.handle(['/echo/1.0.0', '/echo/1.0.1'], echoHandler)
+    expect(libp2p.upgrader.protocols.size).to.equal(2)
+    expect(libp2p.upgrader.protocols.get('/echo/1.0.0')).to.equal(echoHandler)
+    expect(libp2p.upgrader.protocols.get('/echo/1.0.1')).to.equal(echoHandler)
+
+    libp2p.unhandle(['/echo/1.0.0'])
+    expect(libp2p.upgrader.protocols.size).to.equal(1)
+    expect(libp2p.upgrader.protocols.get('/echo/1.0.0')).to.equal(undefined)
+    expect(libp2p.upgrader.protocols.get('/echo/1.0.1')).to.equal(echoHandler)
+  })
+
+  it('should emit connect and disconnect events', async () => {
+    const remotePeer = peers[1]
+    libp2p = new Libp2p({
+      peerInfo: peers[0],
+      modules: {
+        transport: [Transport],
+        streamMuxer: [Muxer],
+        connEncryption: [mockCrypto]
+      }
+    })
+
+    const remoteUpgrader = new Upgrader({
+      localPeer: remotePeer.id,
+      muxers: new Map([[Muxer.multicodec, Muxer]]),
+      cryptos: new Map([[mockCrypto.tag, mockCrypto]])
+    })
+
+    const { inbound, outbound } = mockMultiaddrConnPair({ addrs, remotePeer: remotePeer.id })
+
+    // Spy on emit for easy verification
+    sinon.spy(libp2p, 'emit')
+
+    // Upgrade and check the connect event
+    const connections = await Promise.all([
+      libp2p.upgrader.upgradeOutbound(outbound),
+      remoteUpgrader.upgradeInbound(inbound)
+    ])
+    expect(libp2p.emit.callCount).to.equal(1)
+    let [event, peerInfo] = libp2p.emit.getCall(0).args
+    expect(event).to.equal('peer:connect')
+    expect(peerInfo.id.isEqual(remotePeer.id)).to.equal(true)
+
+    // Close and check the disconnect event
+    await Promise.all(connections.map(conn => conn.close()))
+    expect(libp2p.emit.callCount).to.equal(2)
+    ;([event, peerInfo] = libp2p.emit.getCall(1).args)
+    expect(event).to.equal('peer:disconnect')
+    expect(peerInfo.id.isEqual(remotePeer.id)).to.equal(true)
+  })
+})
diff --git a/test/utils/mockCrypto.js b/test/utils/mockCrypto.js
new file mode 100644
index 00000000..d013cec2
--- /dev/null
+++ b/test/utils/mockCrypto.js
@@ -0,0 +1,24 @@
+'use strict'
+
+const PeerId = require('peer-id')
+const Peers = require('../fixtures/peers')
+
+module.exports = {
+  tag: '/insecure',
+  secureInbound: (localPeer, stream) => {
+    return {
+      conn: stream,
+      remotePeer: localPeer
+    }
+  },
+  secureOutbound: async (localPeer, stream, remotePeer) => {
+    // Crypto should always return a remotePeer
+    if (!remotePeer) {
+      remotePeer = await PeerId.createFromJSON(Peers[0])
+    }
+    return {
+      conn: stream,
+      remotePeer: remotePeer
+    }
+  }
+}
diff --git a/test/utils/mockMultiaddrConn.js b/test/utils/mockMultiaddrConn.js
new file mode 100644
index 00000000..617f6604
--- /dev/null
+++ b/test/utils/mockMultiaddrConn.js
@@ -0,0 +1,43 @@
+'use strict'
+
+const duplexPair = require('it-pair/duplex')
+const abortable = require('abortable-iterator')
+const AbortController = require('abort-controller')
+
+/**
+ * Returns both sides of a mocked MultiaddrConnection
+ * @param {object} options
+ * @param {Multiaddr[]} options.addrs Should contain two addresses for the local and remote peer
+ * @param {PeerId} options.remotePeer The peer that is being "dialed"
+ * @returns {{inbound:MultiaddrConnection, outbound:MultiaddrConnection}}
+ */
+module.exports = function mockMultiaddrConnPair ({ addrs, remotePeer }) {
+  const controller = new AbortController()
+
+  const [inbound, outbound] = duplexPair()
+  outbound.localAddr = addrs[0]
+  outbound.remoteAddr = addrs[1].encapsulate(`/p2p/${remotePeer.toB58String()}`)
+  outbound.timeline = {
+    open: Date.now()
+  }
+  outbound.close = () => {
+    outbound.timeline.close = Date.now()
+    controller.abort()
+  }
+
+  inbound.localAddr = addrs[1]
+  inbound.remoteAddr = addrs[0]
+  inbound.timeline = {
+    open: Date.now()
+  }
+  inbound.close = () => {
+    inbound.timeline.close = Date.now()
+    controller.abort()
+  }
+
+  // Make the sources abortable so we can close them easily
+  inbound.source = abortable(inbound.source, controller.signal)
+  outbound.source = abortable(outbound.source, controller.signal)
+
+  return { inbound, outbound }
+}