ONOS checkin based on commit tag e796610b1f721d02f9b0e213cf6f7790c10ecd60

Change-Id: Ife8810491034fe7becdba75dda20de4267bd15cd

22 files changed, 3224 insertions, 0 deletions

diff --git a/framework/src/onos/utils/nio/pom.xml b/framework/src/onos/utils/nio/pom.xml
new file mode 100644
index 00000000..b9e4d447
--- /dev/null
+++ b/framework/src/onos/utils/nio/pom.xml
@@ -0,0 +1,58 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2014 Open Networking Laboratory
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.onosproject</groupId>
+        <artifactId>onlab-utils</artifactId>
+        <version>1.3.0-SNAPSHOT</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+
+    <artifactId>onlab-nio</artifactId>
+    <packaging>bundle</packaging>
+
+    <description>Fast network I/O using Java NIO</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava-testlib</artifactId>
+            <scope>test</scope>
+        </dependency>
+                <dependency>
+            <groupId>commons-pool</groupId>
+            <artifactId>commons-pool</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onlab-misc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onlab-junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AbstractMessage.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AbstractMessage.java
new file mode 100644
index 00000000..16bb9359
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AbstractMessage.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+/**
+ * Base {@link Message} implementation.
+ */
+public abstract class AbstractMessage implements Message {
+
+    protected int length;
+
+    @Override
+    public int length() {
+        return length;
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AcceptorLoop.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AcceptorLoop.java
new file mode 100644
index 00000000..e416f3be
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/AcceptorLoop.java
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import java.io.IOException;
+import java.net.SocketAddress;
+import java.net.StandardSocketOptions;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.ServerSocketChannel;
+import java.util.Iterator;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Selector loop derivative tailored to acceptConnection inbound connections.
+ */
+public abstract class AcceptorLoop extends SelectorLoop {
+
+    private SocketAddress listenAddress;
+    private ServerSocketChannel socketChannel;
+
+    /**
+     * Creates an acceptor loop with the specified selection timeout and
+     * accepting connections on the the given address.
+     *
+     * @param selectTimeout selection timeout; specified in millis
+     * @param listenAddress socket address where to listen for connections
+     * @throws IOException if the backing selector cannot be opened
+     */
+    public AcceptorLoop(long selectTimeout, SocketAddress listenAddress)
+            throws IOException {
+        super(selectTimeout);
+        this.listenAddress = checkNotNull(listenAddress, "Address cannot be null");
+    }
+
+    /**
+     * Hook to accept an inbound connection on the specified socket channel.
+     *
+     * @param channel socketChannel where an accept operation awaits
+     * @throws IOException if the accept operation cannot be processed
+     */
+    protected abstract void acceptConnection(ServerSocketChannel channel) throws IOException;
+
+    /**
+     * Opens a new server socket channel configured in non-blocking mode and
+     * bound to the loop's listen address.
+     *
+     * @throws IOException if unable to open or configure the socket channel
+     */
+    protected synchronized void openChannel() throws IOException {
+        socketChannel = ServerSocketChannel.open();
+        socketChannel.configureBlocking(false);
+        socketChannel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
+        socketChannel.register(selector, SelectionKey.OP_ACCEPT);
+        socketChannel.bind(listenAddress);
+    }
+
+    /**
+     * Closes the server socket channel.
+     *
+     * @throws IOException if unable to close the socketChannel
+     */
+    protected synchronized void closechannel() throws IOException {
+        if (socketChannel != null) {
+            socketChannel.close();
+            socketChannel = null;
+        }
+    }
+
+    @Override
+    public void shutdown() {
+        try {
+            closechannel();
+        } catch (IOException e) {
+            log.warn("Unable to close the socketChannel", e);
+        }
+        super.shutdown();
+    }
+
+    @Override
+    protected void loop() throws IOException {
+        openChannel();
+        notifyReady();
+
+        // Keep looping until told otherwise.
+        while (isRunning()) {
+            // Attempt a selection; if no operations selected or if signalled
+            // to shutdown, spin through.
+            int count = selector.select(selectTimeout);
+            if (count == 0 || !isRunning()) {
+                continue;
+            }
+
+            // Iterate over all keys selected for an operation and process them.
+            Iterator<SelectionKey> keys = selector.selectedKeys().iterator();
+            while (keys.hasNext()) {
+                // Fetch the key and remove it from the pending list.
+                SelectionKey key = keys.next();
+                keys.remove();
+
+                // If the key has a pending acceptConnection operation, process it.
+                if (key.isAcceptable()) {
+                    acceptConnection((ServerSocketChannel) key.channel());
+                }
+            }
+        }
+    }
+
+}
+
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/IOLoop.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/IOLoop.java
new file mode 100644
index 00000000..106df7b2
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/IOLoop.java
@@ -0,0 +1,302 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import java.io.IOException;
+import java.nio.channels.ByteChannel;
+import java.nio.channels.CancelledKeyException;
+import java.nio.channels.ClosedChannelException;
+import java.nio.channels.SelectableChannel;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.SocketChannel;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Queue;
+import java.util.Set;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.CopyOnWriteArraySet;
+
+/**
+ * I/O loop for driving inbound &amp; outbound {@link Message} transfer via
+ * {@link MessageStream}.
+ *
+ * @param <M> message type
+ * @param <S> message stream type
+ */
+public abstract class IOLoop<M extends Message, S extends MessageStream<M>>
+        extends SelectorLoop {
+
+    // Queue of requests for new message streams to enter the IO loop processing.
+    private final Queue<NewStreamRequest> newStreamRequests = new ConcurrentLinkedQueue<>();
+
+    // Carries information required for admitting a new message stream.
+    private class NewStreamRequest {
+        private final S stream;
+        private final SelectableChannel channel;
+        private final int op;
+
+        public NewStreamRequest(S stream, SelectableChannel channel, int op) {
+            this.stream = stream;
+            this.channel = channel;
+            this.op = op;
+        }
+    }
+
+    // Set of message streams currently admitted into the IO loop.
+    private final Set<MessageStream<M>> streams = new CopyOnWriteArraySet<>();
+
+    /**
+     * Creates an IO loop with the given selection timeout.
+     *
+     * @param timeout selection timeout in milliseconds
+     * @throws IOException if the backing selector cannot be opened
+     */
+    public IOLoop(long timeout) throws IOException {
+        super(timeout);
+    }
+
+    /**
+     * Returns the number of message stream in custody of the loop.
+     *
+     * @return number of message streams
+     */
+    public int streamCount() {
+        return streams.size();
+    }
+
+    /**
+     * Creates a new message stream backed by the specified socket channel.
+     *
+     * @param byteChannel backing byte channel
+     * @return newly created message stream
+     */
+    protected abstract S createStream(ByteChannel byteChannel);
+
+    /**
+     * Removes the specified message stream from the IO loop.
+     *
+     * @param stream message stream to remove
+     */
+    protected void removeStream(MessageStream<M> stream) {
+        streams.remove(stream);
+    }
+
+    /**
+     * Processes the list of messages extracted from the specified message
+     * stream.
+     *
+     * @param messages non-empty list of received messages
+     * @param stream   message stream from which the messages were extracted
+     */
+    protected abstract void processMessages(List<M> messages, MessageStream<M> stream);
+
+    /**
+     * Completes connection request pending on the given selection key.
+     *
+     * @param key selection key holding the pending connect operation.
+     * @throws IOException when I/O exception of some sort has occurred
+     */
+    protected void connect(SelectionKey key) throws IOException {
+        SocketChannel ch = (SocketChannel) key.channel();
+        ch.finishConnect();
+        if (key.isValid()) {
+            key.interestOps(SelectionKey.OP_READ);
+        }
+    }
+
+    /**
+     * Processes an IO operation pending on the specified key.
+     *
+     * @param key selection key holding the pending I/O operation.
+     */
+    protected void processKeyOperation(SelectionKey key) {
+        @SuppressWarnings("unchecked")
+        S stream = (S) key.attachment();
+
+        try {
+            // If the key is not valid, bail out.
+            if (!key.isValid()) {
+                stream.close();
+                return;
+            }
+
+            // If there is a pending connect operation, complete it.
+            if (key.isConnectable()) {
+                try {
+                    connect(key);
+                } catch (IOException | IllegalStateException e) {
+                    log.warn("Unable to complete connection", e);
+                }
+            }
+
+            // If there is a read operation, slurp as much data as possible.
+            if (key.isReadable()) {
+                List<M> messages = stream.read();
+
+                // No messages or failed flush imply disconnect; bail.
+                if (messages == null || stream.hadError()) {
+                    stream.close();
+                    return;
+                }
+
+                // If there were any messages read, process them.
+                if (!messages.isEmpty()) {
+                    try {
+                        processMessages(messages, stream);
+                    } catch (RuntimeException e) {
+                        onError(stream, e);
+                    }
+                }
+            }
+
+            // If there are pending writes, flush them
+            if (key.isWritable()) {
+                stream.flushIfPossible();
+            }
+
+            // If there were any issued flushing, close the stream.
+            if (stream.hadError()) {
+                stream.close();
+            }
+
+        } catch (CancelledKeyException e) {
+            // Key was cancelled, so silently close the stream
+            stream.close();
+        } catch (IOException e) {
+            if (!stream.isClosed() && !isResetByPeer(e)) {
+                log.warn("Unable to process IO", e);
+            }
+            stream.close();
+        }
+    }
+
+    // Indicates whether or not this exception is caused by 'reset by peer'.
+    private boolean isResetByPeer(IOException e) {
+        Throwable cause = e.getCause();
+        return cause != null && cause instanceof IOException &&
+                cause.getMessage().contains("reset by peer");
+    }
+
+    /**
+     * Hook to allow intercept of any errors caused during message processing.
+     * Default behaviour is to rethrow the error.
+     *
+     * @param stream message stream involved in the error
+     * @param error  the runtime exception
+     */
+    protected void onError(S stream, RuntimeException error) {
+        throw error;
+    }
+
+    /**
+     * Admits a new message stream backed by the specified socket channel
+     * with a pending accept operation.
+     *
+     * @param channel backing socket channel
+     * @return newly accepted message stream
+     */
+    public S acceptStream(SocketChannel channel) {
+        return createAndAdmit(channel, SelectionKey.OP_READ);
+    }
+
+
+    /**
+     * Admits a new message stream backed by the specified socket channel
+     * with a pending connect operation.
+     *
+     * @param channel backing socket channel
+     * @return newly connected message stream
+     */
+    public S connectStream(SocketChannel channel) {
+        return createAndAdmit(channel, SelectionKey.OP_CONNECT);
+    }
+
+    /**
+     * Creates a new message stream backed by the specified socket channel
+     * and admits it into the IO loop.
+     *
+     * @param channel socket channel
+     * @param op      pending operations mask to be applied to the selection
+     *                key as a set of initial interestedOps
+     * @return newly created message stream
+     */
+    private synchronized S createAndAdmit(SocketChannel channel, int op) {
+        S stream = createStream(channel);
+        streams.add(stream);
+        newStreamRequests.add(new NewStreamRequest(stream, channel, op));
+        selector.wakeup();
+        return stream;
+    }
+
+    /**
+     * Safely admits new streams into the IO loop.
+     */
+    private void admitNewStreams() {
+        Iterator<NewStreamRequest> it = newStreamRequests.iterator();
+        while (isRunning() && it.hasNext()) {
+            try {
+                NewStreamRequest request = it.next();
+                it.remove();
+                SelectionKey key = request.channel.register(selector, request.op,
+                                                            request.stream);
+                request.stream.setKey(key);
+            } catch (ClosedChannelException e) {
+                log.warn("Unable to admit new message stream", e);
+            }
+        }
+    }
+
+    @Override
+    protected void loop() throws IOException {
+        notifyReady();
+
+        // Keep going until told otherwise.
+        while (isRunning()) {
+            admitNewStreams();
+
+            // Process flushes & write selects on all streams
+            for (MessageStream<M> stream : streams) {
+                stream.flushIfWriteNotPending();
+            }
+
+            // Select keys and process them.
+            int count = selector.select(selectTimeout);
+            if (count > 0 && isRunning()) {
+                Iterator<SelectionKey> it = selector.selectedKeys().iterator();
+                while (it.hasNext()) {
+                    SelectionKey key = it.next();
+                    it.remove();
+                    processKeyOperation(key);
+                }
+            }
+        }
+    }
+
+    /**
+     * Prunes the registered streams by discarding any stale ones.
+     *
+     * @return number of remaining streams
+     */
+    public synchronized int pruneStaleStreams() {
+        for (MessageStream<M> stream : streams) {
+            if (stream.isStale()) {
+                stream.close();
+            }
+        }
+        return streams.size();
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/Message.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/Message.java
new file mode 100644
index 00000000..c1a339e0
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/Message.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+/**
+ * Representation of a message transferred via {@link MessageStream}.
+ */
+public interface Message {
+
+    /**
+     * Gets the message length in bytes.
+     *
+     * @return number of bytes
+     */
+    int length();
+
+}
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/MessageStream.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/MessageStream.java
new file mode 100644
index 00000000..a19e8aac
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/MessageStream.java
@@ -0,0 +1,424 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import org.onlab.util.Counter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.ByteChannel;
+import java.nio.channels.SelectionKey;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static java.lang.System.currentTimeMillis;
+import static java.nio.ByteBuffer.allocateDirect;
+
+/**
+ * Bi-directional message stream for transferring messages to &amp; from the
+ * network via two byte buffers.
+ *
+ * @param <M> message type
+ */
+public abstract class MessageStream<M extends Message> {
+
+    protected Logger log = LoggerFactory.getLogger(getClass());
+
+    private final IOLoop<M, ?> loop;
+    private final ByteChannel channel;
+    private final int maxIdleMillis;
+
+    private final ByteBuffer inbound;
+    private ByteBuffer outbound;
+    private SelectionKey key;
+
+    private volatile boolean closed = false;
+    private volatile boolean writePending;
+    private volatile boolean writeOccurred;
+
+    private Exception ioError;
+    private long lastActiveTime;
+
+    private final Counter bytesIn = new Counter();
+    private final Counter messagesIn = new Counter();
+    private final Counter bytesOut = new Counter();
+    private final Counter messagesOut = new Counter();
+
+    /**
+     * Creates a message stream associated with the specified IO loop and
+     * backed by the given byte channel.
+     *
+     * @param loop          IO loop
+     * @param byteChannel   backing byte channel
+     * @param bufferSize    size of the backing byte buffers
+     * @param maxIdleMillis maximum number of millis the stream can be idle
+     *                      before it will be closed
+     */
+    protected MessageStream(IOLoop<M, ?> loop, ByteChannel byteChannel,
+                            int bufferSize, int maxIdleMillis) {
+        this.loop = checkNotNull(loop, "Loop cannot be null");
+        this.channel = checkNotNull(byteChannel, "Byte channel cannot be null");
+
+        checkArgument(maxIdleMillis > 0, "Idle time must be positive");
+        this.maxIdleMillis = maxIdleMillis;
+
+        inbound = allocateDirect(bufferSize);
+        outbound = allocateDirect(bufferSize);
+    }
+
+    /**
+     * Gets a single message from the specified byte buffer; this is
+     * to be done without manipulating the buffer via flip, reset or clear.
+     *
+     * @param buffer byte buffer
+     * @return read message or null if there are not enough bytes to read
+     * a complete message
+     */
+    protected abstract M read(ByteBuffer buffer);
+
+    /**
+     * Puts the specified message into the specified byte buffer; this is
+     * to be done without manipulating the buffer via flip, reset or clear.
+     *
+     * @param message message to be write into the buffer
+     * @param buffer  byte buffer
+     */
+    protected abstract void write(M message, ByteBuffer buffer);
+
+    /**
+     * Closes the message buffer.
+     */
+    public void close() {
+        synchronized (this) {
+            if (closed) {
+                return;
+            }
+            closed = true;
+        }
+
+        bytesIn.freeze();
+        bytesOut.freeze();
+        messagesIn.freeze();
+        messagesOut.freeze();
+
+        loop.removeStream(this);
+        if (key != null) {
+            try {
+                key.cancel();
+                key.channel().close();
+            } catch (IOException e) {
+                log.warn("Unable to close stream", e);
+            }
+        }
+    }
+
+    /**
+     * Indicates whether this buffer has been closed.
+     *
+     * @return true if this stream has been closed
+     */
+    public synchronized boolean isClosed() {
+        return closed;
+    }
+
+    /**
+     * Returns the stream IO selection key.
+     *
+     * @return socket channel registration selection key
+     */
+    public SelectionKey key() {
+        return key;
+    }
+
+    /**
+     * Binds the selection key to be used for driving IO operations on the stream.
+     *
+     * @param key IO selection key
+     */
+    public void setKey(SelectionKey key) {
+        this.key = key;
+        this.lastActiveTime = currentTimeMillis();
+    }
+
+    /**
+     * Returns the IO loop to which this stream is bound.
+     *
+     * @return I/O loop used to drive this stream
+     */
+    public IOLoop<M, ?> loop() {
+        return loop;
+    }
+
+    /**
+     * Indicates whether the any prior IO encountered an error.
+     *
+     * @return true if a write failed
+     */
+    public boolean hadError() {
+        return ioError != null;
+    }
+
+    /**
+     * Gets the prior IO error, if one occurred.
+     *
+     * @return IO error; null if none occurred
+     */
+    public Exception getError() {
+        return ioError;
+    }
+
+    /**
+     * Reads, without blocking, a list of messages from the stream.
+     * The list will be empty if there were not messages pending.
+     *
+     * @return list of messages or null if backing channel has been closed
+     * @throws IOException if messages could not be read
+     */
+    public List<M> read() throws IOException {
+        try {
+            int read = channel.read(inbound);
+            if (read != -1) {
+                // Read the messages one-by-one and add them to the list.
+                List<M> messages = new ArrayList<>();
+                M message;
+                inbound.flip();
+                while ((message = read(inbound)) != null) {
+                    messages.add(message);
+                    messagesIn.add(1);
+                    bytesIn.add(message.length());
+                }
+                inbound.compact();
+
+                // Mark the stream with current time to indicate liveness.
+                lastActiveTime = currentTimeMillis();
+                return messages;
+            }
+            return null;
+
+        } catch (Exception e) {
+            throw new IOException("Unable to read messages", e);
+        }
+    }
+
+    /**
+     * Writes the specified list of messages to the stream.
+     *
+     * @param messages list of messages to write
+     * @throws IOException if error occurred while writing the data
+     */
+    public void write(List<M> messages) throws IOException {
+        synchronized (this) {
+            // First write all messages.
+            for (M m : messages) {
+                append(m);
+            }
+            flushUnlessAlreadyPlanningTo();
+        }
+    }
+
+    /**
+     * Writes the given message to the stream.
+     *
+     * @param message message to write
+     * @throws IOException if error occurred while writing the data
+     */
+    public void write(M message) throws IOException {
+        synchronized (this) {
+            append(message);
+            flushUnlessAlreadyPlanningTo();
+        }
+    }
+
+    // Appends the specified message into the internal buffer, growing the
+    // buffer if required.
+    private void append(M message) {
+        // If the buffer does not have sufficient length double it.
+        while (outbound.remaining() < message.length()) {
+            doubleSize();
+        }
+        write(message, outbound);
+        messagesOut.add(1);
+        bytesOut.add(message.length());
+    }
+
+    // Forces a flush, unless one is planned already.
+    private void flushUnlessAlreadyPlanningTo() throws IOException {
+        if (!writeOccurred && !writePending) {
+            flush();
+        }
+    }
+
+    /**
+     * Flushes any pending writes.
+     *
+     * @throws IOException if flush failed
+     */
+    public void flush() throws IOException {
+        synchronized (this) {
+            if (!writeOccurred && !writePending) {
+                outbound.flip();
+                try {
+                    channel.write(outbound);
+                } catch (IOException e) {
+                    if (!closed && !Objects.equals(e.getMessage(), "Broken pipe")) {
+                        log.warn("Unable to write data", e);
+                        ioError = e;
+                    }
+                }
+                lastActiveTime = currentTimeMillis();
+                writeOccurred = true;
+                writePending = outbound.hasRemaining();
+                outbound.compact();
+            }
+        }
+    }
+
+    /**
+     * Indicates whether the stream has bytes to be written to the channel.
+     *
+     * @return true if there are bytes to be written
+     */
+    boolean isWritePending() {
+        synchronized (this) {
+            return writePending;
+        }
+    }
+
+
+    /**
+     * Indicates whether data has been written but not flushed yet.
+     *
+     * @return true if flush is required
+     */
+    boolean isFlushRequired() {
+        synchronized (this) {
+            return outbound.position() > 0;
+        }
+    }
+
+    /**
+     * Attempts to flush data, internal stream state and channel availability
+     * permitting. Invoked by the driver I/O loop during handling of writable
+     * selection key.
+     * <p>
+     * Resets the internal state flags {@code writeOccurred} and
+     * {@code writePending}.
+     * </p>
+     * @throws IOException if implicit flush failed
+     */
+    void flushIfPossible() throws IOException {
+        synchronized (this) {
+            writePending = false;
+            writeOccurred = false;
+            if (outbound.position() > 0) {
+                flush();
+            }
+        }
+        key.interestOps(SelectionKey.OP_READ);
+    }
+
+    /**
+     * Attempts to flush data, internal stream state and channel availability
+     * permitting and if other writes are not pending. Invoked by the driver
+     * I/O loop prior to entering select wait. Resets the internal
+     * {@code writeOccurred} state flag.
+     *
+     * @throws IOException if implicit flush failed
+     */
+    void flushIfWriteNotPending() throws IOException {
+        synchronized (this) {
+            writeOccurred = false;
+            if (!writePending && outbound.position() > 0) {
+                flush();
+            }
+        }
+        if (isWritePending()) {
+            key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
+        }
+    }
+
+    /**
+     * Doubles the size of the outbound buffer.
+     */
+    private void doubleSize() {
+        ByteBuffer newBuffer = allocateDirect(outbound.capacity() * 2);
+        outbound.flip();
+        newBuffer.put(outbound);
+        outbound = newBuffer;
+    }
+
+    /**
+     * Returns the maximum number of milliseconds the stream is allowed
+     * without any read/write operations.
+     *
+     * @return number if millis of permissible idle time
+     */
+    protected int maxIdleMillis() {
+        return maxIdleMillis;
+    }
+
+
+    /**
+     * Returns true if the given stream has gone stale.
+     *
+     * @return true if the stream is stale
+     */
+    boolean isStale() {
+        return currentTimeMillis() - lastActiveTime > maxIdleMillis() && key != null;
+    }
+
+    /**
+     * Returns the inbound bytes counter.
+     *
+     * @return inbound bytes counter
+     */
+    public Counter bytesIn() {
+        return bytesIn;
+    }
+
+    /**
+     * Returns the outbound bytes counter.
+     *
+     * @return outbound bytes counter
+     */
+    public Counter bytesOut() {
+        return bytesOut;
+    }
+
+    /**
+     * Returns the inbound messages counter.
+     *
+     * @return inbound messages counter
+     */
+    public Counter messagesIn() {
+        return messagesIn;
+    }
+
+    /**
+     * Returns the outbound messages counter.
+     *
+     * @return outbound messages counter
+     */
+    public Counter messagesOut() {
+        return messagesOut;
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/SelectorLoop.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/SelectorLoop.java
new file mode 100644
index 00000000..95a9b61e
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/SelectorLoop.java
@@ -0,0 +1,175 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.nio.channels.Selector;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.lang.System.currentTimeMillis;
+
+/**
+ * Abstraction of an I/O processing loop based on an NIO selector.
+ */
+public abstract class SelectorLoop implements Runnable {
+
+    protected final Logger log = LoggerFactory.getLogger(getClass());
+
+    /**
+     * Selector used by this loop to pace the I/O operations.
+     */
+    protected final Selector selector;
+
+    /**
+     * Selection operations timeout; specified in millis.
+     */
+    protected long selectTimeout;
+
+    /**
+     * Retains the error that caused the loop to exit prematurely.
+     */
+    private Throwable error;
+
+    // State indicator
+    private enum State { STARTING, STARTED, STOPPING, STOPPED };
+    private volatile State state = State.STOPPED;
+
+    /**
+     * Creates a new selector loop with the given selection timeout.
+     *
+     * @param selectTimeout selection timeout; specified in millis
+     * @throws IOException if the backing selector cannot be opened
+     */
+    public SelectorLoop(long selectTimeout) throws IOException {
+        checkArgument(selectTimeout > 0, "Timeout must be positive");
+        this.selectTimeout = selectTimeout;
+        this.selector = openSelector();
+    }
+
+    /**
+     * Opens a new selector for the use by the loop.
+     *
+     * @return newly open selector
+     * @throws IOException if the backing selector cannot be opened
+     */
+    protected Selector openSelector() throws IOException {
+        return Selector.open();
+    }
+
+    /**
+     * Indicates that the loop is marked to run.
+     * @return true if the loop is marked to run
+     */
+    protected boolean isRunning() {
+        return state == State.STARTED || state == State.STARTING;
+    }
+
+    /**
+     * Returns the error, if there was one, that caused the loop to terminate
+     * prematurely.
+     *
+     * @return error or null if there was none
+     */
+    public Throwable getError() {
+        return error;
+    }
+
+    /**
+     * Contains the body of the I/O selector loop.
+     *
+     * @throws IOException if an error is encountered while selecting I/O
+     */
+    protected abstract void loop() throws IOException;
+
+    @Override
+    public void run() {
+        error = null;
+        state = State.STARTING;
+        try {
+            loop();
+        } catch (Exception e) {
+            error = e;
+            log.error("Loop aborted", e);
+        }
+        notifyDone();
+    }
+
+    /**
+     * Notifies observers waiting for loop to become ready.
+     */
+    protected synchronized void notifyReady() {
+        state = State.STARTED;
+        notifyAll();
+    }
+
+    /**
+     * Triggers loop shutdown.
+     */
+    public void shutdown() {
+        // Mark the loop as no longer running and wake up the selector.
+        state = State.STOPPING;
+        selector.wakeup();
+    }
+
+    /**
+     * Notifies observers waiting for loop to fully stop.
+     */
+    private synchronized void notifyDone() {
+        state = State.STOPPED;
+        notifyAll();
+    }
+
+    /**
+     * Waits for the loop execution to start.
+     *
+     * @param timeout number of milliseconds to wait
+     * @return true if loop started in time
+     */
+    public final synchronized boolean awaitStart(long timeout) {
+        long max = currentTimeMillis() + timeout;
+        while (state != State.STARTED && (currentTimeMillis() < max)) {
+            try {
+                wait(timeout);
+            } catch (InterruptedException e) {
+                throw new RuntimeException("Interrupted", e);
+            }
+        }
+        return state == State.STARTED;
+    }
+
+    /**
+     * Waits for the loop execution to stop.
+     *
+     * @param timeout number of milliseconds to wait
+     * @return true if loop finished in time
+     */
+    public final synchronized boolean awaitStop(long timeout) {
+        long max = currentTimeMillis() + timeout;
+        while (state != State.STOPPED && (currentTimeMillis() < max)) {
+            try {
+                wait(timeout);
+            } catch (InterruptedException e) {
+                throw new RuntimeException("Interrupted", e);
+            }
+        }
+        return state == State.STOPPED;
+    }
+
+
+}
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/package-info.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/package-info.java
new file mode 100644
index 00000000..0d58b568
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/package-info.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Mechanism to transfer messages over network using IO loop and
+ * message stream, backed by NIO byte buffers.
+ */
+package org.onlab.nio;
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultIOLoop.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultIOLoop.java
new file mode 100644
index 00000000..0d977929
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultIOLoop.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio.service;
+
+import java.io.IOException;
+import java.nio.channels.ByteChannel;
+import java.nio.channels.SelectionKey;
+import java.util.List;
+import java.util.function.Consumer;
+
+import org.onlab.nio.IOLoop;
+import org.onlab.nio.MessageStream;
+
+/**
+ * IOLoop for transporting DefaultMessages.
+ */
+public class DefaultIOLoop extends IOLoop<DefaultMessage, DefaultMessageStream> {
+
+    public static final int SELECT_TIMEOUT_MILLIS = 500;
+    private static final int MAX_IDLE_TIMEOUT_MILLIS = 1000;
+    private static final int BUFFER_SIZE = 1024 * 1024;
+    private final Consumer<DefaultMessage> consumer;
+
+    public DefaultIOLoop(Consumer<DefaultMessage> consumer) throws IOException {
+        this(SELECT_TIMEOUT_MILLIS, consumer);
+    }
+
+    public DefaultIOLoop(long timeout, Consumer<DefaultMessage> consumer) throws IOException {
+        super(timeout);
+        this.consumer = consumer;
+    }
+
+    @Override
+    protected DefaultMessageStream createStream(ByteChannel byteChannel) {
+        return new DefaultMessageStream(this, byteChannel, BUFFER_SIZE, MAX_IDLE_TIMEOUT_MILLIS);
+    }
+
+    @Override
+    protected void processMessages(List<DefaultMessage> messages, MessageStream<DefaultMessage> stream) {
+        messages.forEach(consumer);
+    }
+
+    @Override
+    protected void connect(SelectionKey key) throws IOException {
+        DefaultMessageStream stream = (DefaultMessageStream) key.attachment();
+        try {
+            super.connect(key);
+            stream.connected();
+        } catch (Exception e) {
+            stream.connectFailed(e);
+        }
+    }
+}
\ No newline at end of file
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultMessage.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultMessage.java
new file mode 100644
index 00000000..591d49b3
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultMessage.java
@@ -0,0 +1,104 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio.service;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import org.onlab.nio.AbstractMessage;
+import org.onlab.packet.IpAddress;
+import org.onlab.util.ByteArraySizeHashPrinter;
+import org.onosproject.store.cluster.messaging.Endpoint;
+
+import com.google.common.base.Charsets;
+import com.google.common.base.MoreObjects;
+
+/**
+ * Default message.
+ */
+public class DefaultMessage extends AbstractMessage {
+
+    private long id;
+    private Endpoint sender;
+    private String type;
+    private byte[] payload;
+
+    /**
+     * Creates a new message with the specified data.
+     *
+     * @param id message id
+     * @param type message type
+     * @param sender sender endpoint
+     * @param payload message payload
+     */
+    DefaultMessage(long id, Endpoint sender, String type, byte[] payload) {
+        this.id = id;
+        this.type = checkNotNull(type, "Type cannot be null");
+        this.sender = checkNotNull(sender, "Sender cannot be null");
+        this.payload = checkNotNull(payload, "Payload cannot be null");
+
+        byte[] messageTypeBytes = type.getBytes(Charsets.UTF_8);
+        IpAddress senderIp = sender.host();
+        byte[] ipOctets = senderIp.toOctets();
+
+        length = 25 + ipOctets.length + messageTypeBytes.length + payload.length;
+    }
+
+    /**
+     * Returns message id.
+     *
+     * @return message id
+     */
+    public long id() {
+        return id;
+    }
+
+    /**
+     * Returns message sender.
+     *
+     * @return message sender
+     */
+    public Endpoint sender() {
+        return sender;
+    }
+
+    /**
+     * Returns message type.
+     *
+     * @return message type
+     */
+    public String type() {
+        return type;
+    }
+
+    /**
+     * Returns message payload.
+     *
+     * @return payload
+     */
+    public byte[] payload() {
+        return payload;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("id", id)
+                .add("type", type)
+                .add("sender", sender)
+                .add("payload", ByteArraySizeHashPrinter.of(payload))
+                .toString();
+    }
+}
\ No newline at end of file
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultMessageStream.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultMessageStream.java
new file mode 100644
index 00000000..a7dd3c04
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/DefaultMessageStream.java
@@ -0,0 +1,139 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio.service;
+
+import java.nio.ByteBuffer;
+import java.nio.channels.ByteChannel;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.onlab.nio.IOLoop;
+import org.onlab.nio.MessageStream;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpAddress.Version;
+import org.onosproject.store.cluster.messaging.Endpoint;
+
+import com.google.common.base.Charsets;
+
+/**
+ * Default bi-directional message stream for transferring messages to &amp; from the
+ * network via two byte buffers.
+ */
+public class DefaultMessageStream extends MessageStream<DefaultMessage> {
+
+    private final CompletableFuture<Void> connectFuture = new CompletableFuture<>();
+
+    public DefaultMessageStream(
+            IOLoop<DefaultMessage, ?> loop,
+            ByteChannel byteChannel,
+            int bufferSize,
+            int maxIdleMillis) {
+        super(loop, byteChannel, bufferSize, maxIdleMillis);
+    }
+
+    public CompletableFuture<DefaultMessageStream> connectedFuture() {
+        return connectFuture.thenApply(v -> this);
+    }
+
+    private final AtomicInteger messageLength = new AtomicInteger(-1);
+
+    @Override
+    protected DefaultMessage read(ByteBuffer buffer) {
+        if (messageLength.get() == -1) {
+            // check if we can read the message length.
+            if (buffer.remaining() < Integer.BYTES) {
+                return null;
+            } else {
+                messageLength.set(buffer.getInt());
+            }
+        }
+
+        if (buffer.remaining() < messageLength.get()) {
+            return null;
+        }
+
+        long id = buffer.getLong();
+        Version ipVersion = buffer.get() == 0x0 ? Version.INET : Version.INET6;
+        byte[] octects = new byte[IpAddress.byteLength(ipVersion)];
+        buffer.get(octects);
+        IpAddress senderIp = IpAddress.valueOf(ipVersion, octects);
+        int senderPort = buffer.getInt();
+        int messageTypeByteLength = buffer.getInt();
+        byte[] messageTypeBytes = new byte[messageTypeByteLength];
+        buffer.get(messageTypeBytes);
+        String messageType = new String(messageTypeBytes, Charsets.UTF_8);
+        int payloadLength = buffer.getInt();
+        byte[] payloadBytes = new byte[payloadLength];
+        buffer.get(payloadBytes);
+
+        // reset for next message
+        messageLength.set(-1);
+
+        return new DefaultMessage(id, new Endpoint(senderIp, senderPort), messageType, payloadBytes);
+    }
+
+    @Override
+    protected void write(DefaultMessage message, ByteBuffer buffer) {
+        Endpoint sender = message.sender();
+        byte[] messageTypeBytes = message.type().getBytes(Charsets.UTF_8);
+        IpAddress senderIp = sender.host();
+        byte[] ipOctets = senderIp.toOctets();
+        byte[] payload = message.payload();
+
+        int messageLength = 21 + ipOctets.length + messageTypeBytes.length + payload.length;
+
+        buffer.putInt(messageLength);
+
+        buffer.putLong(message.id());
+
+        if (senderIp.version() == Version.INET) {
+            buffer.put((byte) 0x0);
+        } else {
+            buffer.put((byte) 0x1);
+        }
+        buffer.put(ipOctets);
+
+        // write sender port
+        buffer.putInt(sender.port());
+
+        // write length of message type
+        buffer.putInt(messageTypeBytes.length);
+
+        // write message type bytes
+        buffer.put(messageTypeBytes);
+
+        // write payload length
+        buffer.putInt(payload.length);
+
+        // write payload.
+        buffer.put(payload);
+    }
+
+    /**
+     * Callback invoked when the stream is successfully connected.
+     */
+    public void connected() {
+        connectFuture.complete(null);
+    }
+
+    /**
+     * Callback invoked when the stream fails to connect.
+     * @param cause failure cause
+     */
+    public void connectFailed(Throwable cause) {
+        connectFuture.completeExceptionally(cause);
+    }
+}
\ No newline at end of file
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/IOLoopMessaging.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/IOLoopMessaging.java
new file mode 100644
index 00000000..c195d160
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/IOLoopMessaging.java
@@ -0,0 +1,334 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio.service;
+
+import static org.onlab.util.Tools.groupedThreads;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+import org.apache.commons.pool.KeyedPoolableObjectFactory;
+import org.apache.commons.pool.impl.GenericKeyedObjectPool;
+import org.onlab.nio.AcceptorLoop;
+import org.onlab.nio.SelectorLoop;
+import org.onosproject.store.cluster.messaging.Endpoint;
+import org.onosproject.store.cluster.messaging.MessagingService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.RemovalListener;
+import com.google.common.cache.RemovalNotification;
+import com.google.common.collect.Lists;
+
+/**
+ * MessagingService implementation based on IOLoop.
+ */
+public class IOLoopMessaging implements MessagingService {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private static final String REPLY_MESSAGE_TYPE = "ONOS_REQUEST_REPLY";
+
+    static final long TIMEOUT = 1000;
+
+    static final boolean SO_NO_DELAY = false;
+    static final int SO_SEND_BUFFER_SIZE = 128 * 1024;
+    static final int SO_RCV_BUFFER_SIZE = 128 * 1024;
+
+    private static final int NUM_WORKERS = 8;
+
+    private AcceptorLoop acceptorLoop;
+    private final ExecutorService acceptorThreadPool =
+            Executors.newSingleThreadExecutor(groupedThreads("onos/nio/messaging", "acceptor"));
+    private final ExecutorService ioThreadPool =
+            Executors.newFixedThreadPool(NUM_WORKERS, groupedThreads("onos/nio/messaging", "io-loop-worker-%d"));
+
+    private final List<DefaultIOLoop> ioLoops = Lists.newArrayList();
+
+    private int lastWorker = -1;
+
+    private final AtomicBoolean started = new AtomicBoolean(false);
+    private Endpoint localEp;
+
+    private GenericKeyedObjectPool<Endpoint, DefaultMessageStream> streams =
+            new GenericKeyedObjectPool<>(new DefaultMessageStreamFactory());
+
+    private final ConcurrentMap<String, Consumer<DefaultMessage>> handlers = new ConcurrentHashMap<>();
+    private final AtomicLong messageIdGenerator = new AtomicLong(0);
+    private final Cache<Long, CompletableFuture<byte[]>> responseFutures = CacheBuilder.newBuilder()
+            .removalListener(new RemovalListener<Long, CompletableFuture<byte[]>>() {
+                @Override
+                public void onRemoval(RemovalNotification<Long, CompletableFuture<byte[]>> entry) {
+                    if (entry.wasEvicted()) {
+                        entry.getValue().completeExceptionally(new TimeoutException("Timedout waiting for reply"));
+                    }
+                }
+            })
+            .build();
+
+    /**
+     * Activates IO Loops.
+     *
+     * @param localEp local end-point
+     * @throws IOException is activation fails
+     */
+    public void start(Endpoint localEp) throws IOException {
+        if (started.get()) {
+            log.warn("IOMessaging is already running at {}", localEp);
+            return;
+        }
+        this.localEp = localEp;
+        streams.setLifo(false);
+        this.acceptorLoop = new DefaultAcceptorLoop(new InetSocketAddress(localEp.host().toString(), localEp.port()));
+
+        for (int i = 0; i < NUM_WORKERS; i++) {
+            ioLoops.add(new DefaultIOLoop(this::dispatchLocally));
+        }
+
+        ioLoops.forEach(ioThreadPool::execute);
+        acceptorThreadPool.execute(acceptorLoop);
+        ioLoops.forEach(loop -> loop.awaitStart(TIMEOUT));
+        acceptorLoop.awaitStart(TIMEOUT);
+        started.set(true);
+    }
+
+    /**
+     * Shuts down IO loops.
+     */
+    public void stop() {
+        if (started.get()) {
+            ioLoops.forEach(SelectorLoop::shutdown);
+            acceptorLoop.shutdown();
+            ioThreadPool.shutdown();
+            acceptorThreadPool.shutdown();
+            started.set(false);
+        }
+    }
+
+
+    @Override
+    public CompletableFuture<Void> sendAsync(Endpoint ep, String type, byte[] payload) {
+        DefaultMessage message = new DefaultMessage(
+                messageIdGenerator.incrementAndGet(),
+                localEp,
+                type,
+                payload);
+        return sendAsync(ep, message);
+    }
+
+    protected CompletableFuture<Void> sendAsync(Endpoint ep, DefaultMessage message) {
+        CompletableFuture<Void> future = new CompletableFuture<>();
+        if (ep.equals(localEp)) {
+            dispatchLocally(message);
+            future.complete(null);
+            return future;
+        }
+
+        DefaultMessageStream stream = null;
+        try {
+            stream = streams.borrowObject(ep);
+            stream.write(message);
+            future.complete(null);
+        } catch (Exception e) {
+            future.completeExceptionally(e);
+        } finally {
+            try {
+                streams.returnObject(ep, stream);
+            } catch (Exception e) {
+                log.warn("Failed to return stream to pool");
+            }
+        }
+        return future;
+    }
+
+    @Override
+    public CompletableFuture<byte[]> sendAndReceive(
+            Endpoint ep,
+            String type,
+            byte[] payload) {
+        CompletableFuture<byte[]> response = new CompletableFuture<>();
+        Long messageId = messageIdGenerator.incrementAndGet();
+        responseFutures.put(messageId, response);
+        DefaultMessage message = new DefaultMessage(messageId, localEp, type, payload);
+        try {
+            sendAsync(ep, message);
+        } catch (Exception e) {
+            responseFutures.invalidate(messageId);
+            response.completeExceptionally(e);
+        }
+        return response;
+    }
+
+    @Override
+    public void registerHandler(String type, Consumer<byte[]> handler, Executor executor) {
+        handlers.put(type, message -> executor.execute(() -> handler.accept(message.payload())));
+    }
+
+    @Override
+    public void registerHandler(String type, Function<byte[], byte[]> handler, Executor executor) {
+        handlers.put(type, message -> executor.execute(() -> {
+            byte[] responsePayload = handler.apply(message.payload());
+            if (responsePayload != null) {
+                DefaultMessage response = new DefaultMessage(message.id(),
+                        localEp,
+                        REPLY_MESSAGE_TYPE,
+                        responsePayload);
+                sendAsync(message.sender(), response).whenComplete((result, error) -> {
+                    log.debug("Failed to respond", error);
+                });
+            }
+        }));
+    }
+
+    @Override
+    public void registerHandler(String type, Function<byte[], CompletableFuture<byte[]>> handler) {
+        handlers.put(type, message -> {
+            handler.apply(message.payload()).whenComplete((result, error) -> {
+                if (error == null) {
+                    DefaultMessage response = new DefaultMessage(message.id(),
+                        localEp,
+                        REPLY_MESSAGE_TYPE,
+                        result);
+                    sendAsync(message.sender(), response).whenComplete((r, e) -> {
+                        if (e != null) {
+                            log.debug("Failed to respond", e);
+                        }
+                    });
+                }
+            });
+        });
+    }
+
+    @Override
+    public void unregisterHandler(String type) {
+        handlers.remove(type);
+    }
+
+    protected void dispatchLocally(DefaultMessage message) {
+        String type = message.type();
+        if (REPLY_MESSAGE_TYPE.equals(type)) {
+            try {
+                CompletableFuture<byte[]> futureResponse =
+                        responseFutures.getIfPresent(message.id());
+                if (futureResponse != null) {
+                    futureResponse.complete(message.payload());
+                } else {
+                    log.warn("Received a reply for message id:[{}]. "
+                            + " from {}. But was unable to locate the"
+                            + " request handle", message.id(), message.sender());
+                }
+            } finally {
+                responseFutures.invalidate(message.id());
+            }
+            return;
+        }
+        Consumer<DefaultMessage> handler = handlers.get(type);
+        if (handler != null) {
+            handler.accept(message);
+        } else {
+            log.debug("No handler registered for {}", type);
+        }
+    }
+
+    // Get the next worker to which a client should be assigned
+    private synchronized DefaultIOLoop nextWorker() {
+        lastWorker = (lastWorker + 1) % NUM_WORKERS;
+        return ioLoops.get(lastWorker);
+    }
+
+    /**
+     * Initiates open connection request and registers the pending socket
+     * channel with the given IO loop.
+     *
+     * @param loop loop with which the channel should be registered
+     * @throws java.io.IOException if the socket could not be open or connected
+     */
+    private DefaultMessageStream createConnection(Endpoint ep, DefaultIOLoop loop) throws IOException {
+        SocketAddress sa = new InetSocketAddress(ep.host().toString(), ep.port());
+        SocketChannel ch = SocketChannel.open();
+        ch.configureBlocking(false);
+        DefaultMessageStream stream = loop.connectStream(ch);
+        ch.connect(sa);
+        return stream;
+    }
+
+    // Loop for accepting client connections
+    private class DefaultAcceptorLoop extends AcceptorLoop {
+
+        public DefaultAcceptorLoop(SocketAddress address) throws IOException {
+            super(DefaultIOLoop.SELECT_TIMEOUT_MILLIS, address);
+        }
+
+        @Override
+        protected void acceptConnection(ServerSocketChannel channel) throws IOException {
+            SocketChannel sc = channel.accept();
+            sc.configureBlocking(false);
+
+            Socket so = sc.socket();
+            so.setTcpNoDelay(SO_NO_DELAY);
+            so.setReceiveBufferSize(SO_RCV_BUFFER_SIZE);
+            so.setSendBufferSize(SO_SEND_BUFFER_SIZE);
+
+            nextWorker().acceptStream(sc);
+        }
+    }
+
+    private class DefaultMessageStreamFactory implements KeyedPoolableObjectFactory<Endpoint, DefaultMessageStream> {
+
+        @Override
+        public void activateObject(Endpoint endpoint, DefaultMessageStream stream) throws Exception {
+        }
+
+        @Override
+        public void destroyObject(Endpoint ep, DefaultMessageStream stream) throws Exception {
+            stream.close();
+        }
+
+        @Override
+        public DefaultMessageStream makeObject(Endpoint ep) throws Exception {
+            DefaultMessageStream stream = createConnection(ep, nextWorker()).connectedFuture().get();
+            log.info("Established a new connection to {}", ep);
+            return stream;
+        }
+
+        @Override
+        public void passivateObject(Endpoint ep, DefaultMessageStream stream) throws Exception {
+        }
+
+        @Override
+        public boolean validateObject(Endpoint ep, DefaultMessageStream stream) {
+            return stream.isClosed();
+        }
+    }
+}
diff --git a/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/package-info.java b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/package-info.java
new file mode 100644
index 00000000..399a2b95
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/main/java/org/onlab/nio/service/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Assembly for sending and receiving messages using the I/O loop mechanism.
+ */
+package org.onlab.nio.service;
\ No newline at end of file
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/AbstractLoopTest.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/AbstractLoopTest.java
new file mode 100644
index 00000000..2b4a85cd
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/AbstractLoopTest.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import org.junit.Before;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+import static org.junit.Assert.fail;
+import static org.onlab.util.Tools.namedThreads;
+
+/**
+ * Base class for various NIO loop unit tests.
+ */
+public abstract class AbstractLoopTest {
+
+    protected static final long MAX_MS_WAIT = 1500;
+
+    /** Block on specified countdown latch. Return when countdown reaches
+     * zero, or fail the test if the {@value #MAX_MS_WAIT} ms timeout expires.
+     *
+     * @param latch the latch
+     * @param label an identifying label
+     */
+    protected void waitForLatch(CountDownLatch latch, String label) {
+        try {
+            boolean ok = latch.await(MAX_MS_WAIT, TimeUnit.MILLISECONDS);
+            if (!ok) {
+                fail("Latch await timeout! [" + label + "]");
+            }
+        } catch (InterruptedException e) {
+            System.out.println("Latch interrupt [" + label + "] : " + e);
+            fail("Unexpected interrupt");
+        }
+    }
+
+    protected ExecutorService exec;
+
+    @Before
+    public void setUp() {
+        exec = newSingleThreadExecutor(namedThreads("test"));
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/AcceptorLoopTest.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/AcceptorLoopTest.java
new file mode 100644
index 00000000..f04a0126
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/AcceptorLoopTest.java
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2014-2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
+import java.nio.channels.ServerSocketChannel;
+import java.util.concurrent.CountDownLatch;
+
+import static org.junit.Assert.assertEquals;
+import static org.onlab.junit.TestTools.delay;
+
+/**
+ * Unit tests for AcceptLoop.
+ */
+public class AcceptorLoopTest extends AbstractLoopTest {
+
+    private static final int PICK_EPHEMERAL = 0;
+
+    private static final SocketAddress SOCK_ADDR = new InetSocketAddress("127.0.0.1", PICK_EPHEMERAL);
+
+    private static class MyAcceptLoop extends AcceptorLoop {
+        private final CountDownLatch loopStarted = new CountDownLatch(1);
+        private final CountDownLatch loopFinished = new CountDownLatch(1);
+        private final CountDownLatch runDone = new CountDownLatch(1);
+        private final CountDownLatch ceaseLatch = new CountDownLatch(1);
+
+        private int acceptCount = 0;
+
+        MyAcceptLoop() throws IOException {
+            super(500, SOCK_ADDR);
+        }
+
+        @Override
+        protected void acceptConnection(ServerSocketChannel ssc) throws IOException {
+            acceptCount++;
+        }
+
+        @Override
+        public void loop() throws IOException {
+            loopStarted.countDown();
+            super.loop();
+            loopFinished.countDown();
+        }
+
+        @Override
+        public void run() {
+            super.run();
+            runDone.countDown();
+        }
+
+        @Override
+        public void shutdown() {
+            super.shutdown();
+            ceaseLatch.countDown();
+        }
+    }
+
+    @Test
+    public void basic() throws IOException {
+        MyAcceptLoop myAccLoop = new MyAcceptLoop();
+        AcceptorLoop accLoop = myAccLoop;
+        exec.execute(accLoop);
+        waitForLatch(myAccLoop.loopStarted, "loopStarted");
+        delay(200); // take a quick nap
+        accLoop.shutdown();
+        waitForLatch(myAccLoop.loopFinished, "loopFinished");
+        waitForLatch(myAccLoop.runDone, "runDone");
+        assertEquals(0, myAccLoop.acceptCount);
+    }
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopIntegrationTest.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopIntegrationTest.java
new file mode 100644
index 00000000..f42c8dc5
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopIntegrationTest.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import java.net.InetAddress;
+import java.util.Random;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import static org.onlab.junit.TestTools.delay;
+
+/**
+ * Integration test for the select, accept and IO loops.
+ */
+public class IOLoopIntegrationTest {
+
+    private static final int THREADS = 6;
+    private static final int TIMEOUT = 60;
+    private static final int MESSAGE_LENGTH = 128;
+
+    private static final int MILLION = 1000000;
+    private static final int MSG_COUNT = 40 * MILLION;
+
+    @Before
+    public void warmUp() throws Exception {
+        Logger.getLogger("").setLevel(Level.SEVERE);
+        try {
+            runTest(MILLION, MESSAGE_LENGTH, 15);
+        } catch (Throwable e) {
+            System.err.println("Failed warmup but moving on.");
+            e.printStackTrace();
+        }
+    }
+
+    // TODO: this test can not pass in some environments, need to be improved
+    @Ignore
+    @Test
+    public void basic() throws Exception {
+        runTest(MILLION, MESSAGE_LENGTH, TIMEOUT);
+    }
+
+    public void longHaul() throws Exception {
+        runTest(MSG_COUNT, MESSAGE_LENGTH, TIMEOUT);
+    }
+
+    private void runTest(int count, int size, int timeout) throws Exception {
+        // Use a random port to prevent conflicts.
+        int port = IOLoopTestServer.PORT + new Random().nextInt(100);
+
+        InetAddress ip = InetAddress.getLoopbackAddress();
+        IOLoopTestServer server = new IOLoopTestServer(ip, THREADS, size, port);
+        IOLoopTestClient client = new IOLoopTestClient(ip, THREADS, count, size, port);
+
+        server.start();
+        client.start();
+        delay(100); // Pause to allow loops to get going
+
+        client.await(timeout);
+        client.report();
+
+        server.stop();
+        server.report();
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopTestClient.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopTestClient.java
new file mode 100644
index 00000000..acc9a08f
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopTestClient.java
@@ -0,0 +1,324 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import com.google.common.collect.Lists;
+import org.onlab.util.Counter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
+import java.nio.channels.ByteChannel;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.SocketChannel;
+import java.text.DecimalFormat;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.FutureTask;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+import static java.lang.String.format;
+import static java.lang.System.nanoTime;
+import static java.lang.System.out;
+import static org.onlab.nio.IOLoopTestServer.PORT;
+import static org.onlab.util.Tools.delay;
+import static org.onlab.util.Tools.namedThreads;
+
+/**
+ * Auxiliary test fixture to measure speed of NIO-based channels.
+ */
+public class IOLoopTestClient {
+
+    private static Logger log = LoggerFactory.getLogger(IOLoopTestClient.class);
+
+    private final InetAddress ip;
+    private final int port;
+    private final int msgCount;
+    private final int msgLength;
+
+    private final List<CustomIOLoop> iloops = new ArrayList<>();
+    private final ExecutorService ipool;
+    private final ExecutorService wpool;
+
+    Counter messages;
+    Counter bytes;
+    long latencyTotal = 0;
+    long latencyCount = 0;
+
+
+    /**
+     * Main entry point to launch the client.
+     *
+     * @param args command-line arguments
+     * @throws java.io.IOException                     if unable to connect to server
+     * @throws InterruptedException                    if latch wait gets interrupted
+     * @throws java.util.concurrent.ExecutionException if wait gets interrupted
+     * @throws java.util.concurrent.TimeoutException   if timeout occurred while waiting for completion
+     */
+    public static void main(String[] args)
+            throws IOException, InterruptedException, ExecutionException, TimeoutException {
+        startStandalone(args);
+
+        System.exit(0);
+    }
+
+    /**
+     * Starts a standalone IO loop test client.
+     *
+     * @param args command-line arguments
+     */
+    public static void startStandalone(String[] args)
+            throws IOException, InterruptedException, ExecutionException, TimeoutException {
+        InetAddress ip = InetAddress.getByName(args.length > 0 ? args[0] : "127.0.0.1");
+        int wc = args.length > 1 ? Integer.parseInt(args[1]) : 6;
+        int mc = args.length > 2 ? Integer.parseInt(args[2]) : 50 * 1000000;
+        int ml = args.length > 3 ? Integer.parseInt(args[3]) : 128;
+        int to = args.length > 4 ? Integer.parseInt(args[4]) : 60;
+
+        log.info("Setting up client with {} workers sending {} {}-byte messages to {} server... ",
+                 wc, mc, ml, ip);
+        IOLoopTestClient client = new IOLoopTestClient(ip, wc, mc, ml, PORT);
+
+        client.start();
+        delay(500);
+
+        client.await(to);
+        client.report();
+    }
+
+    /**
+     * Creates a speed client.
+     *
+     * @param ip   ip address of server
+     * @param wc   worker count
+     * @param mc   message count to send per client
+     * @param ml   message length in bytes
+     * @param port socket port
+     * @throws java.io.IOException if unable to create IO loops
+     */
+    public IOLoopTestClient(InetAddress ip, int wc, int mc, int ml, int port) throws IOException {
+        this.ip = ip;
+        this.port = port;
+        this.msgCount = mc;
+        this.msgLength = ml;
+        this.wpool = Executors.newFixedThreadPool(wc, namedThreads("worker"));
+        this.ipool = Executors.newFixedThreadPool(wc, namedThreads("io-loop"));
+
+        for (int i = 0; i < wc; i++) {
+            iloops.add(new CustomIOLoop());
+        }
+    }
+
+    /**
+     * Starts the client workers.
+     *
+     * @throws java.io.IOException if unable to open connection
+     */
+    public void start() throws IOException {
+        messages = new Counter();
+        bytes = new Counter();
+
+        // First start up all the IO loops
+        for (CustomIOLoop l : iloops) {
+            ipool.execute(l);
+        }
+
+        // Wait for all of them to get going
+        for (CustomIOLoop l : iloops) {
+            l.awaitStart(1000);
+        }
+
+        // ... and Next open all connections; one-per-loop
+        for (CustomIOLoop l : iloops) {
+            openConnection(l);
+        }
+    }
+
+
+    /**
+     * Initiates open connection request and registers the pending socket
+     * channel with the given IO loop.
+     *
+     * @param loop loop with which the channel should be registered
+     * @throws java.io.IOException if the socket could not be open or connected
+     */
+    private void openConnection(CustomIOLoop loop) throws IOException {
+        SocketAddress sa = new InetSocketAddress(ip, port);
+        SocketChannel ch = SocketChannel.open();
+        ch.configureBlocking(false);
+        loop.connectStream(ch);
+        ch.connect(sa);
+    }
+
+
+    /**
+     * Waits for the client workers to complete.
+     *
+     * @param secs timeout in seconds
+     * @throws java.util.concurrent.ExecutionException if execution failed
+     * @throws InterruptedException                    if interrupt occurred while waiting
+     * @throws java.util.concurrent.TimeoutException   if timeout occurred
+     */
+    public void await(int secs) throws InterruptedException,
+            ExecutionException, TimeoutException {
+        for (CustomIOLoop l : iloops) {
+            if (l.worker.task != null) {
+                l.worker.task.get(secs, TimeUnit.SECONDS);
+                latencyTotal += l.latencyTotal;
+                latencyCount += l.latencyCount;
+            }
+        }
+        messages.freeze();
+        bytes.freeze();
+    }
+
+    /**
+     * Reports on the accumulated throughput and latency.
+     */
+    public void report() {
+        DecimalFormat f = new DecimalFormat("#,##0");
+        out.println(format("Client: %s messages; %s bytes; %s mps; %s MBs; %s ns latency",
+                           f.format(messages.total()), f.format(bytes.total()),
+                           f.format(messages.throughput()),
+                           f.format(bytes.throughput() / (1024 * msgLength)),
+                           f.format(latencyTotal / latencyCount)));
+    }
+
+
+    // Loop for transfer of fixed-length messages
+    private class CustomIOLoop extends IOLoop<TestMessage, TestMessageStream> {
+
+        Worker worker = new Worker();
+        long latencyTotal = 0;
+        long latencyCount = 0;
+
+
+        public CustomIOLoop() throws IOException {
+            super(500);
+        }
+
+
+        @Override
+        protected TestMessageStream createStream(ByteChannel channel) {
+            return new TestMessageStream(msgLength, channel, this);
+        }
+
+        @Override
+        protected synchronized void removeStream(MessageStream<TestMessage> stream) {
+            super.removeStream(stream);
+            messages.add(stream.messagesIn().total());
+            bytes.add(stream.bytesIn().total());
+            stream.messagesOut().reset();
+            stream.bytesOut().reset();
+        }
+
+        @Override
+        protected void processMessages(List<TestMessage> messages,
+                                       MessageStream<TestMessage> stream) {
+            for (TestMessage message : messages) {
+                // TODO: summarize latency data better
+                latencyTotal += nanoTime() - message.requestorTime();
+                latencyCount++;
+            }
+            worker.release(messages.size());
+        }
+
+        @Override
+        protected void connect(SelectionKey key) throws IOException {
+            super.connect(key);
+            TestMessageStream b = (TestMessageStream) key.attachment();
+            Worker w = ((CustomIOLoop) b.loop()).worker;
+            w.pump(b);
+        }
+
+    }
+
+    /**
+     * Auxiliary worker to connect and pump batched messages using blocking I/O.
+     */
+    private class Worker implements Runnable {
+
+        private static final int BATCH_SIZE = 50;
+        private static final int PERMITS = 2 * BATCH_SIZE;
+
+        private TestMessageStream stream;
+        private FutureTask<Worker> task;
+
+        // Stuff to throttle pump
+        private final Semaphore semaphore = new Semaphore(PERMITS);
+        private int msgWritten;
+
+        void pump(TestMessageStream stream) {
+            this.stream = stream;
+            task = new FutureTask<>(this, this);
+            wpool.execute(task);
+        }
+
+        @Override
+        public void run() {
+            try {
+                log.info("Worker started...");
+
+                while (msgWritten < msgCount) {
+                    int size = Math.min(BATCH_SIZE, msgCount - msgWritten);
+                    writeBatch(size);
+                    msgWritten += size;
+                }
+
+                // Now try to get all the permits back before sending poison pill
+                semaphore.acquireUninterruptibly(PERMITS);
+                stream.close();
+
+                log.info("Worker done...");
+
+            } catch (IOException e) {
+                log.error("Worker unable to perform I/O", e);
+            }
+        }
+
+
+        private void writeBatch(int size) throws IOException {
+            // Build a batch of messages
+            List<TestMessage> batch = Lists.newArrayListWithCapacity(size);
+            for (int i = 0; i < size; i++) {
+                batch.add(new TestMessage(msgLength, nanoTime(), 0, stream.padding()));
+            }
+            acquire(size);
+            stream.write(batch);
+        }
+
+
+        // Release permits based on the specified number of message credits
+        private void release(int permits) {
+            semaphore.release(permits);
+        }
+
+        // Acquire permit for a single batch
+        private void acquire(int permits) {
+            semaphore.acquireUninterruptibly(permits);
+        }
+
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopTestServer.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopTestServer.java
new file mode 100644
index 00000000..d5ce5f39
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/IOLoopTestServer.java
@@ -0,0 +1,256 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import com.google.common.collect.Lists;
+import org.onlab.util.Counter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.nio.channels.ByteChannel;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.text.DecimalFormat;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static java.lang.String.format;
+import static java.lang.System.out;
+import static org.onlab.util.Tools.delay;
+import static org.onlab.util.Tools.namedThreads;
+
+/**
+ * Auxiliary test fixture to measure speed of NIO-based channels.
+ */
+public class IOLoopTestServer {
+
+    private static Logger log = LoggerFactory.getLogger(IOLoopTestServer.class);
+
+    private static final int PRUNE_FREQUENCY = 1000;
+
+    static final int PORT = 9876;
+    static final long TIMEOUT = 1000;
+
+    static final boolean SO_NO_DELAY = false;
+    static final int SO_SEND_BUFFER_SIZE = 128 * 1024;
+    static final int SO_RCV_BUFFER_SIZE = 128 * 1024;
+
+    static final DecimalFormat FORMAT = new DecimalFormat("#,##0");
+
+    private final AcceptorLoop aloop;
+    private final ExecutorService apool = Executors.newSingleThreadExecutor(namedThreads("accept"));
+
+    private final List<CustomIOLoop> iloops = new ArrayList<>();
+    private final ExecutorService ipool;
+
+    private final int workerCount;
+    private final int msgLength;
+    private int lastWorker = -1;
+
+    Counter messages;
+    Counter bytes;
+
+    /**
+     * Main entry point to launch the server.
+     *
+     * @param args command-line arguments
+     * @throws java.io.IOException if unable to crate IO loops
+     */
+    public static void main(String[] args) throws IOException {
+        startStandalone(args);
+        System.exit(0);
+    }
+
+    /**
+     * Starts a standalone IO loop test server.
+     *
+     * @param args command-line arguments
+     */
+    public static void startStandalone(String[] args) throws IOException {
+        InetAddress ip = InetAddress.getByName(args.length > 0 ? args[0] : "127.0.0.1");
+        int wc = args.length > 1 ? Integer.parseInt(args[1]) : 6;
+        int ml = args.length > 2 ? Integer.parseInt(args[2]) : 128;
+
+        log.info("Setting up the server with {} workers, {} byte messages on {}... ",
+                 wc, ml, ip);
+        IOLoopTestServer server = new IOLoopTestServer(ip, wc, ml, PORT);
+        server.start();
+
+        // Start pruning clients and keep going until their number goes to 0.
+        int remaining = -1;
+        while (remaining == -1 || remaining > 0) {
+            delay(PRUNE_FREQUENCY);
+            int r = server.prune();
+            remaining = remaining == -1 && r == 0 ? remaining : r;
+        }
+        server.stop();
+    }
+
+    /**
+     * Creates a speed server.
+     *
+     * @param ip   optional ip of the adapter where to bind
+     * @param wc   worker count
+     * @param ml   message length in bytes
+     * @param port listen port
+     * @throws java.io.IOException if unable to create IO loops
+     */
+    public IOLoopTestServer(InetAddress ip, int wc, int ml, int port) throws IOException {
+        this.workerCount = wc;
+        this.msgLength = ml;
+        this.ipool = Executors.newFixedThreadPool(workerCount, namedThreads("io-loop"));
+
+        this.aloop = new CustomAcceptLoop(new InetSocketAddress(ip, port));
+        for (int i = 0; i < workerCount; i++) {
+            iloops.add(new CustomIOLoop());
+        }
+    }
+
+    /**
+     * Start the server IO loops and kicks off throughput tracking.
+     */
+    public void start() {
+        messages = new Counter();
+        bytes = new Counter();
+
+        for (CustomIOLoop l : iloops) {
+            ipool.execute(l);
+        }
+        apool.execute(aloop);
+
+        for (CustomIOLoop l : iloops) {
+            l.awaitStart(TIMEOUT);
+        }
+        aloop.awaitStart(TIMEOUT);
+    }
+
+    /**
+     * Stop the server IO loops and freezes throughput tracking.
+     */
+    public void stop() {
+        aloop.shutdown();
+        for (CustomIOLoop l : iloops) {
+            l.shutdown();
+        }
+
+        for (CustomIOLoop l : iloops) {
+            l.awaitStop(TIMEOUT);
+        }
+        aloop.awaitStop(TIMEOUT);
+
+        messages.freeze();
+        bytes.freeze();
+    }
+
+    /**
+     * Reports on the accumulated throughput and latency.
+     */
+    public void report() {
+        DecimalFormat f = new DecimalFormat("#,##0");
+        out.println(format("Server: %s messages; %s bytes; %s mps; %s MBs",
+                           f.format(messages.total()), f.format(bytes.total()),
+                           f.format(messages.throughput()),
+                           f.format(bytes.throughput() / (1024 * msgLength))));
+    }
+
+    /**
+     * Prunes the IO loops of stale message buffers.
+     *
+     * @return number of remaining IO loops among all workers.
+     */
+    public int prune() {
+        int count = 0;
+        for (CustomIOLoop l : iloops) {
+            count += l.pruneStaleStreams();
+        }
+        return count;
+    }
+
+    // Get the next worker to which a client should be assigned
+    private synchronized CustomIOLoop nextWorker() {
+        lastWorker = (lastWorker + 1) % workerCount;
+        return iloops.get(lastWorker);
+    }
+
+    // Loop for transfer of fixed-length messages
+    private class CustomIOLoop extends IOLoop<TestMessage, TestMessageStream> {
+
+        public CustomIOLoop() throws IOException {
+            super(500);
+        }
+
+        @Override
+        protected TestMessageStream createStream(ByteChannel channel) {
+            return new TestMessageStream(msgLength, channel, this);
+        }
+
+        @Override
+        protected void removeStream(MessageStream<TestMessage> stream) {
+            super.removeStream(stream);
+            messages.add(stream.messagesIn().total());
+            bytes.add(stream.bytesIn().total());
+        }
+
+        @Override
+        protected void processMessages(List<TestMessage> messages,
+                                       MessageStream<TestMessage> stream) {
+            try {
+                stream.write(createResponses(messages));
+            } catch (IOException e) {
+                log.error("Unable to echo messages", e);
+            }
+        }
+
+        private List<TestMessage> createResponses(List<TestMessage> messages) {
+            List<TestMessage> responses = Lists.newArrayListWithCapacity(messages.size());
+            for (TestMessage message : messages) {
+                responses.add(new TestMessage(message.length(), message.requestorTime(),
+                                              System.nanoTime(), message.padding()));
+            }
+            return responses;
+        }
+    }
+
+    // Loop for accepting client connections
+    private class CustomAcceptLoop extends AcceptorLoop {
+
+        public CustomAcceptLoop(SocketAddress address) throws IOException {
+            super(500, address);
+        }
+
+        @Override
+        protected void acceptConnection(ServerSocketChannel channel) throws IOException {
+            SocketChannel sc = channel.accept();
+            sc.configureBlocking(false);
+
+            Socket so = sc.socket();
+            so.setTcpNoDelay(SO_NO_DELAY);
+            so.setReceiveBufferSize(SO_RCV_BUFFER_SIZE);
+            so.setSendBufferSize(SO_SEND_BUFFER_SIZE);
+
+            nextWorker().acceptStream(sc);
+            log.info("Connected client");
+        }
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/MessageStreamTest.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/MessageStreamTest.java
new file mode 100644
index 00000000..9965d389
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/MessageStreamTest.java
@@ -0,0 +1,359 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.ByteChannel;
+import java.nio.channels.ClosedChannelException;
+import java.nio.channels.SelectableChannel;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.spi.SelectorProvider;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+/**
+ * Tests of the message message stream implementation.
+ */
+public class MessageStreamTest {
+
+    private static final int SIZE = 64;
+    private static final int BIG_SIZE = 32 * 1024;
+
+    private TestMessage message;
+
+    private TestIOLoop loop;
+    private TestByteChannel channel;
+    private TestMessageStream stream;
+    private TestKey key;
+
+    @Before
+    public void setUp() throws IOException {
+        loop = new TestIOLoop();
+        channel = new TestByteChannel();
+        key = new TestKey(channel);
+        stream = loop.createStream(channel);
+        stream.setKey(key);
+        stream.setNonStrict();
+        message = new TestMessage(SIZE, 0, 0, stream.padding());
+    }
+
+    @After
+    public void tearDown() {
+        loop.shutdown();
+        stream.close();
+    }
+
+    // Validates the state of the message stream
+    private void validate(boolean wp, boolean fr, int read, int written) {
+        assertEquals(wp, stream.isWritePending());
+        assertEquals(fr, stream.isFlushRequired());
+        assertEquals(read, channel.readBytes);
+        assertEquals(written, channel.writtenBytes);
+    }
+
+    @Test
+    public void endOfStream() throws IOException {
+        channel.close();
+        List<TestMessage> messages = stream.read();
+        assertNull(messages);
+    }
+
+    @Test
+    public void bufferGrowth() throws IOException {
+        // Create a stream for big messages and test the growth.
+        stream = new TestMessageStream(BIG_SIZE, channel, loop);
+        TestMessage bigMessage = new TestMessage(BIG_SIZE, 0, 0, stream.padding());
+
+        stream.write(bigMessage);
+        stream.write(bigMessage);
+        stream.write(bigMessage);
+        stream.write(bigMessage);
+        stream.write(bigMessage);
+    }
+
+    @Test
+    public void discardBeforeKey() {
+        // Create a stream that does not yet have the key set and discard it.
+        stream = loop.createStream(channel);
+        assertNull(stream.key());
+        stream.close();
+        // There is not key, so nothing to check; we just expect no problem.
+    }
+
+    @Test
+    public void bufferedRead() throws IOException {
+        channel.bytesToRead = SIZE + 4;
+        List<TestMessage> messages = stream.read();
+        assertEquals(1, messages.size());
+        validate(false, false, SIZE + 4, 0);
+
+        channel.bytesToRead = SIZE - 4;
+        messages = stream.read();
+        assertEquals(1, messages.size());
+        validate(false, false, SIZE * 2, 0);
+    }
+
+    @Test
+    public void bufferedWrite() throws IOException {
+        validate(false, false, 0, 0);
+
+        // First write is immediate...
+        stream.write(message);
+        validate(false, false, 0, SIZE);
+
+        // Second and third get buffered...
+        stream.write(message);
+        validate(false, true, 0, SIZE);
+        stream.write(message);
+        validate(false, true, 0, SIZE);
+
+        // Reset write, which will flush if needed; the next write is again buffered
+        stream.flushIfWriteNotPending();
+        validate(false, false, 0, SIZE * 3);
+        stream.write(message);
+        validate(false, true, 0, SIZE * 3);
+
+        // Select reset, which will flush if needed; the next write is again buffered
+        stream.flushIfPossible();
+        validate(false, false, 0, SIZE * 4);
+        stream.write(message);
+        validate(false, true, 0, SIZE * 4);
+        stream.flush();
+        validate(false, true, 0, SIZE * 4);
+    }
+
+    @Test
+    public void bufferedWriteList() throws IOException {
+        validate(false, false, 0, 0);
+
+        // First write is immediate...
+        List<TestMessage> messages = new ArrayList<>();
+        messages.add(message);
+        messages.add(message);
+        messages.add(message);
+        messages.add(message);
+
+        stream.write(messages);
+        validate(false, false, 0, SIZE * 4);
+
+        stream.write(messages);
+        validate(false, true, 0, SIZE * 4);
+
+        stream.flushIfPossible();
+        validate(false, false, 0, SIZE * 8);
+    }
+
+    @Test
+    public void bufferedPartialWrite() throws IOException {
+        validate(false, false, 0, 0);
+
+        // First write is immediate...
+        stream.write(message);
+        validate(false, false, 0, SIZE);
+
+        // Tell test channel to accept only half.
+        channel.bytesToWrite = SIZE / 2;
+
+        // Second and third get buffered...
+        stream.write(message);
+        validate(false, true, 0, SIZE);
+        stream.flushIfPossible();
+        validate(true, true, 0, SIZE + SIZE / 2);
+    }
+
+    @Test
+    public void bufferedPartialWrite2() throws IOException {
+        validate(false, false, 0, 0);
+
+        // First write is immediate...
+        stream.write(message);
+        validate(false, false, 0, SIZE);
+
+        // Tell test channel to accept only half.
+        channel.bytesToWrite = SIZE / 2;
+
+        // Second and third get buffered...
+        stream.write(message);
+        validate(false, true, 0, SIZE);
+        stream.flushIfWriteNotPending();
+        validate(true, true, 0, SIZE + SIZE / 2);
+    }
+
+    @Test
+    public void bufferedReadWrite() throws IOException {
+        channel.bytesToRead = SIZE + 4;
+        List<TestMessage> messages = stream.read();
+        assertEquals(1, messages.size());
+        validate(false, false, SIZE + 4, 0);
+
+        stream.write(message);
+        validate(false, false, SIZE + 4, SIZE);
+
+        channel.bytesToRead = SIZE - 4;
+        messages = stream.read();
+        assertEquals(1, messages.size());
+        validate(false, false, SIZE * 2, SIZE);
+    }
+
+    // Fake IO driver loop
+    private static class TestIOLoop extends IOLoop<TestMessage, TestMessageStream> {
+
+        public TestIOLoop() throws IOException {
+            super(500);
+        }
+
+        @Override
+        protected TestMessageStream createStream(ByteChannel channel) {
+            return new TestMessageStream(SIZE, channel, this);
+        }
+
+        @Override
+        protected void processMessages(List<TestMessage> messages,
+                                       MessageStream<TestMessage> stream) {
+        }
+
+    }
+
+    // Byte channel test fixture
+    private static class TestByteChannel extends SelectableChannel implements ByteChannel {
+
+        private static final int BUFFER_LENGTH = 1024;
+        byte[] bytes = new byte[BUFFER_LENGTH];
+        int bytesToWrite = BUFFER_LENGTH;
+        int bytesToRead = BUFFER_LENGTH;
+        int writtenBytes = 0;
+        int readBytes = 0;
+
+        @Override
+        public int read(ByteBuffer dst) throws IOException {
+            int l = Math.min(dst.remaining(), bytesToRead);
+            if (bytesToRead > 0) {
+                readBytes += l;
+                dst.put(bytes, 0, l);
+            }
+            return l;
+        }
+
+        @Override
+        public int write(ByteBuffer src) throws IOException {
+            int l = Math.min(src.remaining(), bytesToWrite);
+            writtenBytes += l;
+            src.get(bytes, 0, l);
+            return l;
+        }
+
+        @Override
+        public Object blockingLock() {
+            return null;
+        }
+
+        @Override
+        public SelectableChannel configureBlocking(boolean arg0) throws IOException {
+            return null;
+        }
+
+        @Override
+        public boolean isBlocking() {
+            return false;
+        }
+
+        @Override
+        public boolean isRegistered() {
+            return false;
+        }
+
+        @Override
+        public SelectionKey keyFor(Selector arg0) {
+            return null;
+        }
+
+        @Override
+        public SelectorProvider provider() {
+            return null;
+        }
+
+        @Override
+        public SelectionKey register(Selector arg0, int arg1, Object arg2)
+                throws ClosedChannelException {
+            return null;
+        }
+
+        @Override
+        public int validOps() {
+            return 0;
+        }
+
+        @Override
+        protected void implCloseChannel() throws IOException {
+            bytesToRead = -1;
+        }
+
+    }
+
+    // Selection key text fixture
+    private static class TestKey extends SelectionKey {
+
+        private SelectableChannel channel;
+
+        public TestKey(TestByteChannel channel) {
+            this.channel = channel;
+        }
+
+        @Override
+        public void cancel() {
+        }
+
+        @Override
+        public SelectableChannel channel() {
+            return channel;
+        }
+
+        @Override
+        public int interestOps() {
+            return 0;
+        }
+
+        @Override
+        public SelectionKey interestOps(int ops) {
+            return null;
+        }
+
+        @Override
+        public boolean isValid() {
+            return true;
+        }
+
+        @Override
+        public int readyOps() {
+            return 0;
+        }
+
+        @Override
+        public Selector selector() {
+            return null;
+        }
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/MockSelector.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/MockSelector.java
new file mode 100644
index 00000000..cf5b2bb9
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/MockSelector.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import java.io.IOException;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.spi.AbstractSelectableChannel;
+import java.nio.channels.spi.AbstractSelector;
+import java.util.Set;
+
+/**
+ * A selector instrumented for unit tests.
+ */
+public class MockSelector extends AbstractSelector {
+
+    int wakeUpCount = 0;
+
+    /**
+     * Creates a mock selector, specifying null as the SelectorProvider.
+     */
+    public MockSelector() {
+        super(null);
+    }
+
+    @Override
+    public String toString() {
+        return "{MockSelector: wake=" + wakeUpCount + "}";
+    }
+
+    @Override
+    protected void implCloseSelector() throws IOException {
+    }
+
+    @Override
+    protected SelectionKey register(AbstractSelectableChannel ch, int ops,
+                                    Object att) {
+        return null;
+    }
+
+    @Override
+    public Set<SelectionKey> keys() {
+        return null;
+    }
+
+    @Override
+    public Set<SelectionKey> selectedKeys() {
+        return null;
+    }
+
+    @Override
+    public int selectNow() throws IOException {
+        return 0;
+    }
+
+    @Override
+    public int select(long timeout) throws IOException {
+        return 0;
+    }
+
+    @Override
+    public int select() throws IOException {
+        return 0;
+    }
+
+    @Override
+    public Selector wakeup() {
+        wakeUpCount++;
+        return null;
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/TestMessage.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/TestMessage.java
new file mode 100644
index 00000000..825479b5
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/TestMessage.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Test message for measuring rate and round-trip latency.
+ */
+public class TestMessage extends AbstractMessage {
+
+    private final byte[] padding;
+
+    private final long requestorTime;
+    private final long responderTime;
+
+    /**
+     * Creates a new message with the specified data.
+     *
+     * @param requestorTime requester time
+     * @param responderTime responder time
+     * @param padding       message padding
+     */
+    TestMessage(int length, long requestorTime, long responderTime, byte[] padding) {
+        this.length = length;
+        this.requestorTime = requestorTime;
+        this.responderTime = responderTime;
+        this.padding = checkNotNull(padding, "Padding cannot be null");
+    }
+
+    public long requestorTime() {
+        return requestorTime;
+    }
+
+    public long responderTime() {
+        return responderTime;
+    }
+
+    public byte[] padding() {
+        return padding;
+    }
+
+}
diff --git a/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/TestMessageStream.java b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/TestMessageStream.java
new file mode 100644
index 00000000..fc86beb9
--- /dev/null
+++ b/framework/src/onos/utils/nio/src/test/java/org/onlab/nio/TestMessageStream.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.nio;
+
+import java.nio.ByteBuffer;
+import java.nio.channels.ByteChannel;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkState;
+
+/**
+ * Fixed-length message transfer buffer.
+ */
+public class TestMessageStream extends MessageStream<TestMessage> {
+
+    private static final String E_WRONG_LEN = "Illegal message length: ";
+    private static final long START_TAG = 0xfeedcafedeaddeedL;
+    private static final long END_TAG = 0xbeadcafedeaddeedL;
+    private static final int META_LENGTH = 40;
+
+    private final int length;
+    private boolean isStrict = true;
+
+    public TestMessageStream(int length, ByteChannel ch, IOLoop<TestMessage, ?> loop) {
+        super(loop, ch, 64 * 1024, 500);
+        checkArgument(length >= META_LENGTH, "Length must be greater than header length of 40");
+        this.length = length;
+    }
+
+    void setNonStrict() {
+        isStrict = false;
+    }
+
+    @Override
+    protected TestMessage read(ByteBuffer rb) {
+        if (rb.remaining() < length) {
+            return null;
+        }
+
+        long startTag = rb.getLong();
+        if (isStrict) {
+            checkState(startTag == START_TAG, "Incorrect message start");
+        }
+
+        long size = rb.getLong();
+        long requestorTime = rb.getLong();
+        long responderTime = rb.getLong();
+        byte[] padding = padding();
+        rb.get(padding);
+
+        long endTag = rb.getLong();
+        if (isStrict) {
+            checkState(endTag == END_TAG, "Incorrect message end");
+        }
+
+        return new TestMessage((int) size, requestorTime, responderTime, padding);
+    }
+
+    @Override
+    protected void write(TestMessage message, ByteBuffer wb) {
+        if (message.length() != length) {
+            throw new IllegalArgumentException(E_WRONG_LEN + message.length());
+        }
+
+        wb.putLong(START_TAG);
+        wb.putLong(message.length());
+        wb.putLong(message.requestorTime());
+        wb.putLong(message.responderTime());
+        wb.put(message.padding(), 0, length - META_LENGTH);
+        wb.putLong(END_TAG);
+    }
+
+    public byte[] padding() {
+        return new byte[length - META_LENGTH];
+    }
+}