class VirtualNetworkFilter implements IFloodlightModule, IVirtualNetworkService, IOFMessageListener, IDeviceListener {

    @Override
    public void addHost(MACAddress mac, String guid, String port) {
        if (guid != null) {
            if (log.isDebugEnabled()) {
                log.debug("Adding {} to network ID {} on port {}",
                          new Object[] {mac, guid, port});
            }
            // We ignore old mappings
            macToGuid.put(mac, guid);
            portToMac.put(port, mac);
            if(vNetsByGuid.get(guid)!=null)
                vNetsByGuid.get(guid).addHost(new MACAddress(mac.toBytes()));
        } else {
            log.warn("Could not add MAC {} to network ID {} on port {}, the network does not exist",
                     new Object[] {mac, guid, port});
        }
    }

}