Voyager Reference Guide 351shared features, meaning that their configurations can be shared across clusternodes during the joining process.Clustering ModesIPSO clusters have two modes of operation. Nokia provides this choice so thatIPSO clusters can work in any network environment:! In multicast mode each cluster node receives every packet sent to thecluster and decides whether to process it based on information it receivesfrom the master node. If the node decides not to process the packet(because another node is processing it), it drops the packet.This mode usually offers better throughput because it uses the networkbandwidth more efficiently.Multicast mode uses multicast MAC addresses for each of the nodes. Ifyou use this mode, routers and servers adjacent to the cluster (eitherconnected directly or through a switch or hub) must be able to acceptARP replies that contain a multicast MAC address. Switches connecteddirectly to the cluster must be able to forward packets destined for a single(multicast) MAC address out multiple switch ports. See “Considerationsfor Clustering” for more information about the requirements for routersand switches when using multicast mode.Multicast clustering mode is not related to multicast routing. In fact, IPSOclusters do not forward multicast routing traffic.! In forwarding mode the master cluster node initially receives all thepackets sent to the cluster and decides which node should process thepacket. If it decides that another node should handle the packet, itforwards the packet to that node. Otherwise, the master processes thepacket itself.Use forwarding mode if the routers and switches on either side of thecluster do not support multicast MAC addresses.
