[sebastan_bach]

hi sharky in multicast load sharing mode. in clusterXL deployments the internal devices will have their default gateway pointing to the cluster virtual ip address and similarly on the external interface.

so lets say ur internal users are trying to get to the internet. in this case when the internal router or host does a arp request for the mac address of the virtual ip address any of the active cluster members will respond with a multicast mac to the host. so when the host sends the traffic to the multicast address all the cluster members will receive the frame at layer 2. then each cluster will make a decision whether to process or drop the packet. making sure that no firewalls are processing the same packet and atleast one firewall is processing the packet.

in load sharing unicast mode. in this mode only a single cluster member also called pivot mac address is associated with the cluster virtual ip address.

so here when the host request the mac address of the virtual ip address the pivot responds with his interface mac address. once the pivot receives the frame then only the pivot makes the decision function as to whether forward the packet by himself or forward it to other cluster members. the other members when they receive the packet by the pivot they simply just forward it they don;t make any decision.

the difference in the mode is only how the cluster members receive the packet for load sharing. rest the working on clusterXL remains the same.

hope this help u out.

regards

sebastan