[Falcon] ONOS-3372 Link related Service on gRPC

Change-Id: Ib497d17cb3c0126086a1ce03a6f99ae344320448

@@ -23,6 +23,7 @@ import java.util.concurrent.ConcurrentHashMap;
 
 import org.onosproject.incubator.rpc.RemoteServiceContext;
 import org.onosproject.net.device.DeviceProviderRegistry;
+import org.onosproject.net.link.LinkProviderRegistry;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -49,6 +50,7 @@ public class GrpcRemoteServiceContext implements RemoteServiceContext {
     public GrpcRemoteServiceContext(ManagedChannel channel) {
         this.channel = checkNotNull(channel);
         services.put(DeviceProviderRegistry.class, new DeviceProviderRegistryClientProxy(channel));
+        services.put(LinkProviderRegistry.class, new LinkProviderRegistryClientProxy(channel));
     }
 
 

@@ -21,6 +21,7 @@ import static org.onosproject.incubator.rpc.grpc.GrpcDeviceUtils.translate;
 import static org.onosproject.net.DeviceId.deviceId;
 
 import java.io.IOException;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -47,11 +48,15 @@ import org.onosproject.grpc.Device.UpdatePortStatistics;
 import org.onosproject.grpc.Device.UpdatePorts;
 import org.onosproject.grpc.DeviceProviderRegistryRpcGrpc;
 import org.onosproject.grpc.DeviceProviderRegistryRpcGrpc.DeviceProviderRegistryRpc;
+import org.onosproject.grpc.LinkProviderServiceRpcGrpc;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.MastershipRole;
 import org.onosproject.net.device.DeviceProvider;
 import org.onosproject.net.device.DeviceProviderRegistry;
 import org.onosproject.net.device.DeviceProviderService;
+import org.onosproject.net.link.LinkProvider;
+import org.onosproject.net.link.LinkProviderRegistry;
+import org.onosproject.net.link.LinkProviderService;
 import org.onosproject.net.provider.ProviderId;
 import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
@@ -59,6 +64,7 @@ import org.slf4j.LoggerFactory;
 
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
+import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 
 import io.grpc.Server;
@@ -68,13 +74,15 @@ import io.grpc.stub.StreamObserver;
 // gRPC Server on Metro-side
 // Translates request received on RPC channel, and calls corresponding Service on
 // Metro-ONOS cluster.
+
+// Currently supports DeviceProviderRegistry, LinkProviderService
 /**
  * Server side implementation of gRPC based RemoteService.
  */
 @Component(immediate = true)
 public class GrpcRemoteServiceServer {
 
-    private static final String RPC_PROVIDER_NAME = "org.onosproject.rpc.provider.grpc";
+    static final String RPC_PROVIDER_NAME = "org.onosproject.rpc.provider.grpc";
 
     // TODO pick a number
     public static final int DEFAULT_LISTEN_PORT = 11984;
@@ -84,6 +92,9 @@ public class GrpcRemoteServiceServer {
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected DeviceProviderRegistry deviceProviderRegistry;
 
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected LinkProviderRegistry linkProviderRegistry;
+
 
     @Property(name = "listenPort", intValue = DEFAULT_LISTEN_PORT,
             label = "Port to listen on")
@@ -92,6 +103,11 @@ public class GrpcRemoteServiceServer {
     private Server server;
     private final Set<DeviceProviderServerProxy> registeredProviders = Sets.newConcurrentHashSet();
 
+    // scheme -> ...
+    // updates must be guarded by synchronizing `this`
+    private final Map<String, LinkProviderService> linkProviderServices = Maps.newConcurrentMap();
+    private final Map<String, LinkProvider> linkProviders = Maps.newConcurrentMap();
+
     @Activate
     protected void activate(ComponentContext context) throws IOException {
         modified(context);
@@ -100,6 +116,7 @@ public class GrpcRemoteServiceServer {
         try {
             server  = NettyServerBuilder.forPort(listenPort)
                     .addService(DeviceProviderRegistryRpcGrpc.bindService(new DeviceProviderRegistryServerProxy()))
+                    .addService(LinkProviderServiceRpcGrpc.bindService(new LinkProviderServiceServerProxy(this)))
                     .build().start();
         } catch (IOException e) {
             log.error("Failed to start gRPC server", e);
@@ -117,6 +134,9 @@ public class GrpcRemoteServiceServer {
 
         server.shutdown();
         // Should we wait for shutdown?
+
+        unregisterLinkProviders();
+
         log.info("Stopped");
     }
 
@@ -125,6 +145,40 @@ public class GrpcRemoteServiceServer {
         // TODO support dynamic reconfiguration and restarting server?
     }
 
+    /**
+     * Registers {@link StubLinkProvider} for given ProviderId scheme.
+     *
+     * DO NOT DIRECTLY CALL THIS METHOD.
+     * Only expected to be called from {@link #getLinkProviderServiceFor(String)}.
+     *
+     * @param scheme ProviderId scheme.
+     * @return {@link LinkProviderService} registered.
+     */
+    private synchronized LinkProviderService registerStubLinkProvider(String scheme) {
+        StubLinkProvider provider = new StubLinkProvider(scheme);
+        linkProviders.put(scheme, provider);
+        return linkProviderRegistry.register(provider);
+    }
+
+    /**
+     * Unregisters all registered LinkProviders.
+     */
+    private synchronized void unregisterLinkProviders() {
+        linkProviders.values().forEach(linkProviderRegistry::unregister);
+        linkProviders.clear();
+        linkProviderServices.clear();
+    }
+
+    /**
+     * Gets or creates {@link LinkProviderService} registered for given ProviderId scheme.
+     *
+     * @param scheme ProviderId scheme.
+     * @return {@link LinkProviderService}
+     */
+    protected LinkProviderService getLinkProviderServiceFor(String scheme) {
+        return linkProviderServices.computeIfAbsent(scheme, this::registerStubLinkProvider);
+    }
+
     // RPC Server-side code
     // RPC session Factory
     /**

+/*
+ * 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.onosproject.incubator.rpc.grpc;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import org.onosproject.net.link.LinkProvider;
+import org.onosproject.net.link.LinkProviderRegistry;
+import org.onosproject.net.link.LinkProviderService;
+import org.onosproject.net.provider.AbstractProviderRegistry;
+
+import com.google.api.client.repackaged.com.google.common.annotations.Beta;
+
+import io.grpc.Channel;
+
+/**
+ * Proxy object to handle LinkProviderRegistry calls.
+ */
+@Beta
+public class LinkProviderRegistryClientProxy
+    extends AbstractProviderRegistry<LinkProvider, LinkProviderService>
+    implements LinkProviderRegistry {
+
+    private final Channel channel;
+
+    public LinkProviderRegistryClientProxy(Channel channel) {
+        this.channel = checkNotNull(channel);
+    }
+
+    @Override
+    protected LinkProviderService createProviderService(LinkProvider provider) {
+        return new LinkProviderServiceClientProxy(provider, channel);
+    }
+
+}

+/*
+ * 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.onosproject.incubator.rpc.grpc;
+
+import static org.onosproject.incubator.rpc.grpc.GrpcDeviceUtils.asMap;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+import org.onosproject.grpc.Link.LinkDetectedMsg;
+import org.onosproject.grpc.Link.LinkType;
+import org.onosproject.grpc.Link.LinkVanishedMsg;
+import org.onosproject.grpc.Link.Void;
+import org.onosproject.grpc.LinkProviderServiceRpcGrpc;
+import org.onosproject.grpc.LinkProviderServiceRpcGrpc.LinkProviderServiceRpcFutureStub;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link.Type;
+import org.onosproject.net.link.LinkDescription;
+import org.onosproject.net.link.LinkProvider;
+import org.onosproject.net.link.LinkProviderService;
+import org.onosproject.net.provider.AbstractProviderService;
+import org.onosproject.net.provider.ProviderId;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.api.client.repackaged.com.google.common.annotations.Beta;
+import com.google.common.util.concurrent.ListenableFuture;
+
+import io.grpc.Channel;
+
+/**
+ * Proxy object to handle LinkProviderService calls.
+ *
+ * RPC wise, this will initiate a RPC call on each method invocation.
+ */
+@Beta
+class LinkProviderServiceClientProxy
+    extends AbstractProviderService<LinkProvider>
+    implements LinkProviderService {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private final Channel channel;
+
+    /**
+     * Constructs {@link LinkProviderServiceClientProxy}.
+     *
+     * @param provider {@link LinkProvider}. Only ProviderId scheme is used.
+     * @param channel channel to use to call RPC
+     */
+    protected LinkProviderServiceClientProxy(LinkProvider provider, Channel channel) {
+        super(provider);
+        this.channel = channel;
+    }
+
+    @Override
+    public void linkDetected(LinkDescription linkDescription) {
+        checkValidity();
+
+        LinkProviderServiceRpcFutureStub newStub = LinkProviderServiceRpcGrpc.newFutureStub(channel);
+        ListenableFuture<Void> future = newStub.linkDetected(detectMsg(provider().id(), linkDescription));
+
+        try {
+            // There's no need to wait, but just checking server
+            future.get(500, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
+            log.error("linkDetected({}) failed", linkDescription, e);
+            invalidate();
+            Thread.currentThread().interrupt();
+        } catch (ExecutionException e) {
+            log.error("linkDetected({}) failed", linkDescription, e);
+            invalidate();
+        } catch (TimeoutException e) {
+            log.error("linkDetected({}) failed", linkDescription, e);
+            invalidate();
+        }
+    }
+
+    @Override
+    public void linkVanished(LinkDescription linkDescription) {
+        checkValidity();
+
+        LinkProviderServiceRpcFutureStub newStub = LinkProviderServiceRpcGrpc.newFutureStub(channel);
+        ListenableFuture<Void> future = newStub.linkVanished(vanishMsg(provider().id(), linkDescription));
+
+        try {
+            // There's no need to wait, but just checking server
+            future.get(500, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
+            log.error("linkVanished({}) failed", linkDescription, e);
+            invalidate();
+            Thread.currentThread().interrupt();
+        } catch (ExecutionException e) {
+            log.error("linkVanished({}) failed", linkDescription, e);
+            invalidate();
+        } catch (TimeoutException e) {
+            log.error("linkVanished({}) failed", linkDescription, e);
+            invalidate();
+        }
+    }
+
+    @Override
+    public void linksVanished(ConnectPoint connectPoint) {
+        checkValidity();
+
+        LinkProviderServiceRpcFutureStub newStub = LinkProviderServiceRpcGrpc.newFutureStub(channel);
+        ListenableFuture<Void> future = newStub.linkVanished(vanishMsg(provider().id(), connectPoint));
+
+        try {
+            // There's no need to wait, but just checking server
+            future.get(500, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
+            log.error("linksVanished({}) failed", connectPoint, e);
+            invalidate();
+            Thread.currentThread().interrupt();
+        } catch (ExecutionException e) {
+            log.error("linksVanished({}) failed", connectPoint, e);
+            invalidate();
+        } catch (TimeoutException e) {
+            log.error("linksVanished({}) failed", connectPoint, e);
+            invalidate();
+        }
+    }
+
+    @Override
+    public void linksVanished(DeviceId deviceId) {
+        checkValidity();
+
+        LinkProviderServiceRpcFutureStub newStub = LinkProviderServiceRpcGrpc.newFutureStub(channel);
+        ListenableFuture<Void> future = newStub.linkVanished(vanishMsg(provider().id(), deviceId));
+
+        try {
+            // There's no need to wait, but just checking server
+            future.get(500, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
+            log.error("linksVanished({}) failed", deviceId, e);
+            invalidate();
+            Thread.currentThread().interrupt();
+        } catch (ExecutionException e) {
+            log.error("linksVanished({}) failed", deviceId, e);
+            invalidate();
+        } catch (TimeoutException e) {
+            log.error("linksVanished({}) failed", deviceId, e);
+            invalidate();
+        }
+    }
+
+    /**
+     * Builds {@link LinkDetectedMsg}.
+     *
+     * @param id ProviderId
+     * @param linkDescription {@link LinkDescription}
+     * @return {@link LinkDetectedMsg}
+     */
+    private LinkDetectedMsg detectMsg(ProviderId id,
+                                      LinkDescription linkDescription) {
+        LinkDetectedMsg.Builder builder = LinkDetectedMsg.newBuilder();
+        builder.setProviderId(id.scheme())
+               .setLinkDescription(builder.getLinkDescriptionBuilder()
+                                    .setSrc(translate(linkDescription.src()))
+                                    .setDst(translate(linkDescription.dst()))
+                                    .setType(translate(linkDescription.type()))
+                                    .putAllAnnotations(asMap(linkDescription.annotations()))
+                                    .build()
+                                    );
+        return builder.build();
+    }
+
+    /**
+     * Builds {@link LinkVanishedMsg}.
+     *
+     * @param id ProviderId
+     * @param linkDescription {@link LinkDescription}
+     * @return {@link LinkVanishedMsg}
+     */
+    private LinkVanishedMsg vanishMsg(ProviderId id,
+                                      LinkDescription linkDescription) {
+
+        LinkVanishedMsg.Builder builder = LinkVanishedMsg.newBuilder();
+        builder.setProviderId(id.scheme())
+            .setLinkDescription(builder.getLinkDescriptionBuilder()
+                             .setSrc(translate(linkDescription.src()))
+                             .setDst(translate(linkDescription.dst()))
+                             .setType(translate(linkDescription.type()))
+                             .putAllAnnotations(asMap(linkDescription.annotations()))
+                             .build()
+                             );
+        return builder.build();
+    }
+
+    /**
+     * Builds {@link LinkVanishedMsg}.
+     *
+     * @param id ProviderId
+     * @param connectPoint {@link ConnectPoint}
+     * @return {@link LinkVanishedMsg}
+     */
+    private LinkVanishedMsg vanishMsg(ProviderId id,
+                                      ConnectPoint connectPoint) {
+
+        LinkVanishedMsg.Builder builder = LinkVanishedMsg.newBuilder();
+        builder.setProviderId(id.scheme())
+            .setConnectPoint(translate(connectPoint));
+        return builder.build();
+    }
+
+    /**
+     * Builds {@link LinkVanishedMsg}.
+     *
+     * @param id ProviderId
+     * @param deviceId {@link DeviceId}
+     * @return {@link LinkVanishedMsg}
+     */
+    private LinkVanishedMsg vanishMsg(ProviderId id, DeviceId deviceId) {
+
+        LinkVanishedMsg.Builder builder = LinkVanishedMsg.newBuilder();
+        builder.setProviderId(id.scheme())
+            .setDeviceId(deviceId.toString());
+        return builder.build();
+    }
+
+    /**
+     * Translates ONOS object to gRPC message.
+     *
+     * @param type {@link Link.Type}
+     * @return gRPC LinkType
+     */
+    private LinkType translate(Type type) {
+        switch (type) {
+        case DIRECT:
+            return LinkType.DIRECT;
+        case EDGE:
+            return LinkType.EDGE;
+        case INDIRECT:
+            return LinkType.INDIRECT;
+        case OPTICAL:
+            return LinkType.OPTICAL;
+        case TUNNEL:
+            return LinkType.TUNNEL;
+        case VIRTUAL:
+            return LinkType.VIRTUAL;
+
+        default:
+            return LinkType.DIRECT;
+
+        }
+    }
+
+    /**
+     * Translates ONOS object to gRPC message.
+     *
+     * @param cp {@link ConnectPoint}
+     * @return gRPC ConnectPoint
+     */
+    private org.onosproject.grpc.Link.ConnectPoint translate(ConnectPoint cp) {
+        return org.onosproject.grpc.Link.ConnectPoint.newBuilder()
+                .setDeviceId(cp.deviceId().toString())
+                .setPortNumber(cp.port().toString())
+                .build();
+    }
+
+}

+/*
+ * 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.onosproject.incubator.rpc.grpc;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onosproject.net.DeviceId.deviceId;
+
+import org.onosproject.grpc.Link.LinkDetectedMsg;
+import org.onosproject.grpc.Link.LinkType;
+import org.onosproject.grpc.Link.LinkVanishedMsg;
+import org.onosproject.grpc.Link.Void;
+import org.onosproject.grpc.Link.ConnectPoint.ElementIdCase;
+import org.onosproject.grpc.LinkProviderServiceRpcGrpc.LinkProviderServiceRpc;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.SparseAnnotations;
+import org.onosproject.net.link.DefaultLinkDescription;
+import org.onosproject.net.link.LinkDescription;
+import org.onosproject.net.link.LinkProviderService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.api.client.repackaged.com.google.common.annotations.Beta;
+
+import io.grpc.stub.StreamObserver;
+
+/**
+ * Server-side implementation of gRPC version of LinkProviderService.
+ */
+@Beta
+final class LinkProviderServiceServerProxy
+        implements LinkProviderServiceRpc {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private final GrpcRemoteServiceServer server;
+
+    LinkProviderServiceServerProxy(GrpcRemoteServiceServer server) {
+        this.server = checkNotNull(server);
+    }
+
+    /**
+     * Gets or creates {@link LinkProviderService} registered for given ProviderId scheme.
+     *
+     * @param scheme ProviderId scheme.
+     * @return {@link LinkProviderService}
+     */
+    private LinkProviderService getLinkProviderServiceFor(String scheme) {
+        return server.getLinkProviderServiceFor(scheme);
+    }
+
+    @Override
+    public void linkDetected(LinkDetectedMsg request,
+                             StreamObserver<Void> responseObserver) {
+
+        try {
+            onLinkDetected(request, responseObserver);
+            // If onNext call was not mandatory, it can be removed.
+            responseObserver.onNext(Void.getDefaultInstance());
+            responseObserver.onCompleted();
+        } catch (Exception e) {
+            log.error("Exception caught", e);
+            responseObserver.onError(e);
+        }
+    }
+
+    private void onLinkDetected(LinkDetectedMsg request,
+                                StreamObserver<Void> responseObserver) {
+        String scheme = request.getProviderId();
+
+        LinkProviderService linkProviderService = getLinkProviderServiceFor(scheme);
+
+        LinkDescription linkDescription = translate(request.getLinkDescription());
+        linkProviderService.linkDetected(linkDescription);
+    }
+
+    @Override
+    public void linkVanished(LinkVanishedMsg request,
+                             StreamObserver<Void> responseObserver) {
+        try {
+            onLinksVanished(request, responseObserver);
+            // If onNext call was not mandatory, it can be removed.
+            responseObserver.onNext(Void.getDefaultInstance());
+            responseObserver.onCompleted();
+        } catch (Exception e) {
+            log.error("Exception caught", e);
+            responseObserver.onError(e);
+        }
+    }
+
+    private void onLinksVanished(LinkVanishedMsg request,
+                                 StreamObserver<Void> responseObserver) {
+        String scheme = request.getProviderId();
+        switch (request.getSubjectCase()) {
+        case CONNECT_POINT:
+            ConnectPoint cp = translate(request.getConnectPoint());
+            getLinkProviderServiceFor(scheme).linksVanished(cp);
+            break;
+        case DEVICE_ID:
+            DeviceId did = deviceId(request.getDeviceId());
+            getLinkProviderServiceFor(scheme).linksVanished(did);
+            break;
+        case LINK_DESCRIPTION:
+            LinkDescription desc = translate(request.getLinkDescription());
+            getLinkProviderServiceFor(scheme).linkVanished(desc);
+            break;
+        case SUBJECT_NOT_SET:
+        default:
+            // do nothing
+            break;
+        }
+    }
+
+    /**
+     * Translates gRPC message to corresponding ONOS object.
+     *
+     * @param connectPoint gRPC message.
+     * @return {@link ConnectPoint}
+     */
+    private ConnectPoint translate(org.onosproject.grpc.Link.ConnectPoint connectPoint) {
+        checkArgument(connectPoint.getElementIdCase() == ElementIdCase.DEVICE_ID,
+                      "Only DeviceId supported.");
+        return new ConnectPoint(deviceId(connectPoint.getDeviceId()),
+                                PortNumber.fromString(connectPoint.getPortNumber()));
+    }
+
+    /**
+     * Translates gRPC message to corresponding ONOS object.
+     *
+     * @param linkDescription gRPC message
+     * @return {@link LinkDescription}
+     */
+    private LinkDescription translate(org.onosproject.grpc.Link.LinkDescription linkDescription) {
+        ConnectPoint src = translate(linkDescription.getSrc());
+        ConnectPoint dst = translate(linkDescription.getDst());
+        Link.Type type = translate(linkDescription.getType());
+        SparseAnnotations annotations = GrpcDeviceUtils.asAnnotations(linkDescription.getAnnotations());
+        return new DefaultLinkDescription(src, dst, type, annotations);
+    }
+
+    /**
+     * Translates gRPC message to corresponding ONOS object.
+     *
+     * @param type gRPC message enum
+     * @return {@link Type}
+     */
+    private Link.Type translate(LinkType type) {
+        switch (type) {
+        case DIRECT:
+            return Link.Type.DIRECT;
+        case EDGE:
+            return Link.Type.EDGE;
+        case INDIRECT:
+            return Link.Type.INDIRECT;
+        case OPTICAL:
+            return Link.Type.INDIRECT;
+        case TUNNEL:
+            return Link.Type.TUNNEL;
+        case VIRTUAL:
+            return Link.Type.VIRTUAL;
+
+        case UNRECOGNIZED:
+        default:
+            return Link.Type.DIRECT;
+        }
+    }
+
+}

+/*
+ * 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.onosproject.incubator.rpc.grpc;
+
+import org.onosproject.net.link.LinkProvider;
+import org.onosproject.net.provider.AbstractProvider;
+import org.onosproject.net.provider.ProviderId;
+
+import com.google.api.client.repackaged.com.google.common.annotations.Beta;
+import com.google.common.base.MoreObjects;
+
+/**
+ * Stub LinkProvider to be registered on Server-side.
+ */
+@Beta
+final class StubLinkProvider extends AbstractProvider implements LinkProvider {
+    protected StubLinkProvider(String scheme) {
+        super(new ProviderId(scheme, GrpcRemoteServiceServer.RPC_PROVIDER_NAME));
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("id", id())
+                .toString();
+    }
+}

+syntax = "proto3";
+option java_package = "org.onosproject.grpc";
+
+package Link;
+
+enum LinkType {
+  // Signifies that this is a direct single-segment link.
+  DIRECT = 0;
+
+  // Signifies that this link is potentially comprised from multiple
+  //underlying segments or hops, and as such should be used to tag
+  // links traversing optical paths, tunnels or intervening 'dark'
+  // switches.
+  INDIRECT = 1;
+
+  // Signifies that this link is an edge, i.e. host link.
+  EDGE = 2;
+
+  // Signifies that this link represents a logical link backed by
+  // some form of a tunnel, e.g., GRE, MPLS, ODUk, OCH.
+  TUNNEL = 3;
+
+  // Signifies that this link is realized by fiber (either single channel or WDM).
+  OPTICAL = 4;
+
+  // Signifies that this link is a virtual link or a pseudo-wire.
+  VIRTUAL = 5;
+}
+
+message ConnectPoint {
+  oneof element_id {
+    // DeviceID as String DeviceId#toString
+    string device_id = 1;
+
+    // TODO add support to other element_id if required
+  }
+  // PortNumber as String PortNumber#toString
+  string port_number = 2;
+}
+
+message LinkDescription {
+  ConnectPoint src = 1;
+  ConnectPoint dst = 2;
+  LinkType type = 3;
+  map<string, string> annotations = 4;
+}
+
+// Message te represent no return value
+message Void {}
+
+message LinkDetectedMsg {
+  // ProviderId scheme only
+  string provider_id = 1;
+  LinkDescription link_description = 2;
+}
+
+message LinkVanishedMsg {
+  // ProviderId scheme only
+  string provider_id = 1;
+  oneof subject {
+    LinkDescription link_description = 2;
+    ConnectPoint connect_point = 3;
+    string device_id = 4;
+  }
+}
+
+service LinkProviderServiceRpc {
+  rpc LinkDetected(LinkDetectedMsg) returns (Void);
+  rpc LinkVanished(LinkVanishedMsg) returns (Void);
+}

@@ -17,6 +17,7 @@ package org.onosproject.incubator.rpc.grpc;
 
 import static org.junit.Assert.*;
 import static org.onosproject.net.DeviceId.deviceId;
+import static org.onosproject.net.PortNumber.portNumber;
 
 import java.io.IOException;
 import java.net.ServerSocket;
@@ -37,9 +38,11 @@ import org.onosproject.incubator.rpc.RemoteServiceContext;
 import org.onosproject.incubator.rpc.RemoteServiceContextProvider;
 import org.onosproject.incubator.rpc.RemoteServiceContextProviderService;
 import org.onosproject.incubator.rpc.RemoteServiceProviderRegistry;
+import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.DefaultAnnotations;
 import org.onosproject.net.Device.Type;
 import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
 import org.onosproject.net.MastershipRole;
 import org.onosproject.net.PortNumber;
 import org.onosproject.net.SparseAnnotations;
@@ -51,6 +54,11 @@ import org.onosproject.net.device.DeviceProviderRegistry;
 import org.onosproject.net.device.DeviceProviderService;
 import org.onosproject.net.device.PortDescription;
 import org.onosproject.net.device.PortStatistics;
+import org.onosproject.net.link.DefaultLinkDescription;
+import org.onosproject.net.link.LinkDescription;
+import org.onosproject.net.link.LinkProvider;
+import org.onosproject.net.link.LinkProviderRegistry;
+import org.onosproject.net.link.LinkProviderService;
 import org.onosproject.net.provider.AbstractProviderRegistry;
 import org.onosproject.net.provider.AbstractProviderService;
 import org.onosproject.net.provider.ProviderId;
@@ -99,6 +107,9 @@ public class GrpcRemoteServiceTest {
 
     private MTestDeviceProviderService svDeviceProviderService;
 
+    private ServerSideLinkProviderService svLinkProviderService;
+
+
     private CountDownLatch serverReady;
 
     private URI uri;
@@ -121,6 +132,7 @@ public class GrpcRemoteServiceTest {
         serverReady = new CountDownLatch(1);
         server = new GrpcRemoteServiceServer();
         server.deviceProviderRegistry = new MTestDeviceProviderRegistry();
+        server.linkProviderRegistry = new ServerSideLinkProviderRegistry();
         // todo: pass proper ComponentContext
         server.listenPort = pickListenPort();
         uri = URI.create("grpc://localhost:" + server.listenPort);
@@ -135,6 +147,7 @@ public class GrpcRemoteServiceTest {
     public void tearDown() {
         client.deactivate();
         server.deactivate();
+        svLinkProviderService = null;
     }
 
     private static void assertEqualsButNotSame(Object expected, Object actual) {
@@ -144,7 +157,7 @@ public class GrpcRemoteServiceTest {
     }
 
     @Test
-    public void basics() throws InterruptedException {
+    public void deviceServiceBasics() throws InterruptedException {
         RemoteServiceContext remoteServiceContext = client.get(uri);
         assertNotNull(remoteServiceContext);
 
@@ -217,6 +230,116 @@ public class GrpcRemoteServiceTest {
                       DEVICE_ID, clDeviceProvider.isReachableDid);
     }
 
+    @Test
+    public void linkVanishedDevice() throws InterruptedException {
+        RemoteServiceContext remoteServiceContext = client.get(uri);
+        assertNotNull(remoteServiceContext);
+
+        LinkProviderRegistry providerRegistry = remoteServiceContext.get(LinkProviderRegistry.class);
+        assertNotNull(providerRegistry);
+
+        final String schemeTest = "test";
+        LinkProviderService client = providerRegistry.register(new StubLinkProvider(schemeTest));
+        assertNotNull(client);
+
+        client.linksVanished(DEVICE_ID);
+
+        assertEquals(schemeTest, svLinkProviderService.provider().id().scheme());
+        assertTrue(svLinkProviderService.calls.await(10, TimeUnit.SECONDS));
+        assertEqualsButNotSame(DEVICE_ID, svLinkProviderService.arg);
+    }
+
+    @Test
+    public void linkVanishedPort() throws InterruptedException {
+        RemoteServiceContext remoteServiceContext = client.get(uri);
+        assertNotNull(remoteServiceContext);
+
+        LinkProviderRegistry providerRegistry = remoteServiceContext.get(LinkProviderRegistry.class);
+        assertNotNull(providerRegistry);
+
+        final String schemeTest = "test";
+        LinkProviderService client = providerRegistry.register(new StubLinkProvider(schemeTest));
+        assertNotNull(client);
+
+
+        final ConnectPoint cp = new ConnectPoint(DEVICE_ID, PORT);
+        client.linksVanished(cp);
+        assertEquals(schemeTest, svLinkProviderService.provider().id().scheme());
+        assertTrue(svLinkProviderService.calls.await(10, TimeUnit.SECONDS));
+        assertEqualsButNotSame(cp, svLinkProviderService.arg);
+    }
+
+    @Test
+    public void linkVanishedDescription() throws InterruptedException {
+        RemoteServiceContext remoteServiceContext = client.get(uri);
+        assertNotNull(remoteServiceContext);
+
+        LinkProviderRegistry providerRegistry = remoteServiceContext.get(LinkProviderRegistry.class);
+        assertNotNull(providerRegistry);
+
+        final String schemeTest = "test";
+        LinkProviderService client = providerRegistry.register(new StubLinkProvider(schemeTest));
+        assertNotNull(client);
+
+        ConnectPoint src = new ConnectPoint(deviceId("dev:1"), portNumber(10));
+        ConnectPoint dst = new ConnectPoint(deviceId("dev:2"), portNumber(20));
+        LinkDescription linkDescription = new DefaultLinkDescription(src, dst, Link.Type.DIRECT, ANON);
+        client.linkVanished(linkDescription);
+        assertEquals(schemeTest, svLinkProviderService.provider().id().scheme());
+        assertTrue(svLinkProviderService.calls.await(10, TimeUnit.SECONDS));
+        assertEqualsButNotSame(linkDescription, svLinkProviderService.arg);
+    }
+
+    @Test
+    public void linkDetected() throws InterruptedException {
+        RemoteServiceContext remoteServiceContext = client.get(uri);
+        assertNotNull(remoteServiceContext);
+
+        LinkProviderRegistry providerRegistry = remoteServiceContext.get(LinkProviderRegistry.class);
+        assertNotNull(providerRegistry);
+
+        final String schemeTest = "test";
+        LinkProviderService client = providerRegistry.register(new StubLinkProvider(schemeTest));
+        assertNotNull(client);
+
+        ConnectPoint src = new ConnectPoint(deviceId("dev:1"), portNumber(10));
+        ConnectPoint dst = new ConnectPoint(deviceId("dev:2"), portNumber(20));
+        LinkDescription linkDescription = new DefaultLinkDescription(src, dst, Link.Type.DIRECT, ANON);
+        client.linkDetected(linkDescription);
+        assertEquals(schemeTest, svLinkProviderService.provider().id().scheme());
+        assertTrue(svLinkProviderService.calls.await(10, TimeUnit.SECONDS));
+        assertEqualsButNotSame(linkDescription, svLinkProviderService.arg);
+    }
+
+    @Test
+    public void linkServiceBasics() throws InterruptedException {
+        RemoteServiceContext remoteServiceContext = client.get(uri);
+        assertNotNull(remoteServiceContext);
+
+        LinkProviderRegistry providerRegistry = remoteServiceContext.get(LinkProviderRegistry.class);
+        assertNotNull(providerRegistry);
+
+        final String schemeTest = "test";
+        LinkProviderService client = providerRegistry.register(new StubLinkProvider(schemeTest));
+        assertNotNull(client);
+
+        ConnectPoint src = new ConnectPoint(deviceId("dev:1"), portNumber(10));
+        ConnectPoint dst = new ConnectPoint(deviceId("dev:2"), portNumber(20));
+        LinkDescription linkDescription = new DefaultLinkDescription(src, dst, Link.Type.DIRECT, ANON);
+
+        client.linkDetected(linkDescription);
+        assertEquals(schemeTest, svLinkProviderService.provider().id().scheme());
+        assertTrue(svLinkProviderService.calls.await(10, TimeUnit.SECONDS));
+        assertEqualsButNotSame(linkDescription, svLinkProviderService.arg);
+
+        svLinkProviderService.reset();
+
+        client.linkVanished(linkDescription);
+        assertEquals(schemeTest, svLinkProviderService.provider().id().scheme());
+        assertTrue(svLinkProviderService.calls.await(10, TimeUnit.SECONDS));
+        assertEqualsButNotSame(linkDescription, svLinkProviderService.arg);
+    }
+
     /**
      * Device Provider on CO side.
      */
@@ -395,4 +518,61 @@ public class GrpcRemoteServiceTest {
         }
     }
 
+    public class ServerSideLinkProviderRegistry
+            extends AbstractProviderRegistry<LinkProvider, LinkProviderService>
+            implements LinkProviderRegistry {
+
+        @Override
+        protected LinkProviderService createProviderService(LinkProvider provider) {
+            svLinkProviderService = new ServerSideLinkProviderService(provider);
+            return svLinkProviderService;
+        }
+
+    }
+
+    public class ServerSideLinkProviderService
+            extends AbstractProviderService<LinkProvider>
+            implements LinkProviderService {
+
+        CountDownLatch calls = new CountDownLatch(1);
+        Object arg = null;
+
+        public void reset() {
+            calls = new CountDownLatch(1);
+            arg = null;
+        }
+
+        public ServerSideLinkProviderService(LinkProvider provider) {
+            super(provider);
+        }
+
+        @Override
+        public void linksVanished(DeviceId deviceId) {
+            log.info("linksVanished({})", deviceId);
+            arg = deviceId;
+            calls.countDown();
+        }
+
+        @Override
+        public void linksVanished(ConnectPoint connectPoint) {
+            log.info("linksVanished({})", connectPoint);
+            arg = connectPoint;
+            calls.countDown();
+        }
+
+        @Override
+        public void linkVanished(LinkDescription linkDescription) {
+            log.info("linksVanished({})", linkDescription);
+            arg = linkDescription;
+            calls.countDown();
+        }
+
+        @Override
+        public void linkDetected(LinkDescription linkDescription) {
+            log.info("linkDetected({})", linkDescription);
+            arg = linkDescription;
+            calls.countDown();
+        }
+    }
+
 }