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Building 'Bring Your Own Network'

We are now going to start building BYON. BYON is a service which allows you to spawn virtual networks in which each host is connected to every other host of that virtual network. Basically, each virtual network contains a full mesh of the hosts that make it up.

Part 1: Creating an application

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Part 2: Make it so, Number one

In this part we are going to implement a trivial store for out network service as well as learn how to push intents. The store will be used to store the service's network state (duh!) while the intent framework will allow us to simply connect together every host in the virtual network we create. 

In order to be able to use the Intent Framework the caller must supply an Application ID. Application ID allow ONOS to identify who is consuming which resources as well as track applications. To achieve this, we have to add the following code to our NetworkManager class.

So first, we will need a reference to the CoreService, as it is the service that provides Application IDs. To do this add the follow code to the NetworkManager class.

Code Block
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected CoreService coreService;

This now gives you a reference to the CoreService at runtime. So let's pick up an application Id.

Code Block
languagejava
private ApplicationId appId;

// in activate method
appId = coreService.registerApplication("org.onos.byon");

Make sure to store the Application Id in a class field.

The NetworkManager is going to have to use the store (that we are going to build) to store information therefore we are going to need a reference on a NetworkStore:

Code Block
languagejava
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected NetworkStore store;

Notice that at this point IntelliJ is not happy because the NetworkStore class does not exist. Well, let's crerate it!

Code Block
languagejava
public interface NetworkStore {
    /**
     * Create a named network.
     *
     * @param network network name
     */
    void putNetwork(String network);

    /**
     * Removes a named network.
     *
     * @param network network name
     */
    void removeNetwork(String network);

    /**
     * Returns a set of network names.
     *
     * @return a set of network names
     */
    Set<String> getNetworks();


    /**
     * Adds a host to the given network.
     *
     * @param network network name
     * @param hostId host id
     * @return updated set of hosts in the network (or an empty set if the host
     *         has already been added to the network)
     */
    Set<HostId> addHost(String network, HostId hostId);

    /**
     * Removes a host from the given network.
     *
     * @param network network name
     * @param hostId host id
     */
    void removeHost(String network, HostId hostId);

    /**
     * Returns all the hosts in a network.
     *
     * @param network network name
     * @return set of host ids
     */
    Set<HostId> getHosts(String network);

	/**
     * Adds a set of intents to a network
     *
     * @param network network name
     * @param intents set of intents
     */
    void addIntents(String network, Set<Intent> intents);

    /**
     * Returns a set of intents given a network and a host.
     *
     * @param network network name
     * @param hostId host id
     * @return set of intents
     */
    Set<Intent> removeIntents(String network, HostId hostId);

    /**
     * Returns a set of intents given a network.
     * @param network network name
     * @return set of intents
     */
    Set<Intent> removeIntents(String network);
	
}

Alright so now you have an interface for the NetworkStore, that makes IntelliJ happy. But someone should implement that interface right? Let's create a new class which implements the NetworkStore interface.

Code Block
languagejava
@Component(immediate = true, enabled = true)
@Service
public class SimpleNetworkStore
        implements NetworkStore {

    private static Logger log = LoggerFactory.getLogger(SimpleNetworkStore.class);

    private final Map<String, Set<HostId>> networks = Maps.newHashMap();
    private final Map<String, Set<Intent>> intentsPerNet = Maps.newHashMap();

    @Activate
    protected void activate() {
        log.info("Started");
    }

    @Deactivate
    protected void deactivate() {
        log.info("Stopped");
    }
}

Now as an exercise you must implement the methods of SimpleNetworkStore. Don't hesitate to ask questions here!

Add some Intents

Now that we have a simple store implementation, let's have byon program the network when hosts are added. For this we are going to need the intent framework, so let's grab a reference  to it in the network manager.

 

Code Block
languagejava
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected IntentService intentService;

And we will need the following code to implement the mesh of the hosts in each virtual network.

Code Block
languagejava
    private Set<Intent> addToMesh(HostId src, Set<HostId> existing) {
        if (existing.isEmpty()) {
            return Collections.emptySet();
        }
        IntentOperations.Builder builder = IntentOperations.builder(appId);
        existing.forEach(dst -> {
            if (!src.equals(dst)) {
                builder.addSubmitOperation(new HostToHostIntent(appId, src, dst));
            }
        });
        IntentOperations ops = builder.build();
        intentService.execute(ops);

        return ops.operations().stream().map(IntentOperation::intent)
                .collect(Collectors.toSet());
    }

    private void removeFromMesh(Set<Intent> intents) {
        IntentOperations.Builder builder = IntentOperations.builder(appId);
        intents.forEach(intent -> builder.addWithdrawOperation(intent.id()));
        intentService.execute(builder.build());
    }