Nokia IPSO 4.0 Reference Manual page 372

9
Note
The generation ID included in all PIM hello messages does not change when IP clustering is
used, regardless of whether and how many times PIM is re-enabled. When IP clustering is
implemented, the generation ID is based on the cluster IP address so that all members
advertise the same address. The generation ID included in PIM hello messages of all cluster
nodes does not change unless the cluster IP address is changed.
The multicast data traffic is load-balanced and can be processed by any of the cluster members.
All cluster members sync the dense-mode forwarding state with each other member; therefore, if
any cluster member fails, the new member responsible for the corresponding data traffic has the
same state as the member that failed.
PIM Sparse-Mode
In the Nokia implementation of PIM Sparse-Mode (PIM-SM), depending on its location, the
cluster can function as the designated router, the bootstrap router, the rendezvous point or any
location in the source or shortest-path tree (SPT). All the nodes process PIM control traffic
received by the cluster, and only the master processes most of the control traffic sent from the
cluster. However, hello messages, for example, are sent by all nodes. Some multicast switches
do not forward multicast traffic to interfaces from which they have not received any multicast
traffic. To avoid having a multicast switch fail to forward multicast traffic, all cluster nodes send
periodic PIM hello messages. All messages from each cluster member have the same source IP
address, generation ID, holdtime and designated router priority. Therefore, all neighboring
routers view the cluster as a single neighbor even though they receive hello messages from all
members of the cluster.
Note
The generation ID included in all PIM hello messages does not change when IP clustering is
used, regardless of whether and how many times PIM is re-enabled. When IP clustering is
implemented, the generation ID is based on the cluster IP address so that all members
advertise the same address. The generation ID included in PIM hello messages of all cluster
nodes does not change unless the cluster IP address is changed.
The multicast data traffic is load-balanced and can be processed by any member of the cluster.
However, the cluster is the elected rendezvous point, only the master processes the encapsulated
register messages until the SPT is created.
Note
For both PIM-SM and PIM- DM, the Nokia implementation of IP clustering does not forward
traffic addressed to 244.0.1.144. IP clustering uses multicast to communicate
synchronization messages and has reserved multicast group address 244.0.1.144 for this
purpose. When IP clustering is enabled, IGMP membership messages for this group are
sent on all interfaces that are part of the cluster. Moreover, since this multicast group is not a
link-local group, the designated router on the LAN sends PIM (*, g) PIM messages for this
group to the rendezvous point when PIM-SIM is implemented. If the Nokia appliance is the
372 Nokia Network Voyager for IPSO 4.0 Reference Guide