Prerequisites For Graceful Restart Pim; Information About Graceful Restart Pim - Cisco Nexus 7000 Series Configuration Manual

Configuring PIM and PIM6
Generation ID (GenID) value (defined in RFC 4601) as a mechanism to trigger adjacent PIM neighbors on
an interface to send PIM join messages for all (*, G) and (S, G) states that use that interface as a reverse path
forwarding (RPF) interface. This mechanism enables PIM neighbors to immediately reestablish those states
on the newly active RP.

Prerequisites for Graceful Restart PIM

All Protocol Independent Multicast (PIM) neighbors must be compliant with RFC 4601 and be able to process
Generation ID (GenID) differences in PIM hello messages.

Information About Graceful Restart PIM

Generation IDs
A Generation ID (GenID) is a randomly generated 32-bit value that is regenerated each time protocol
independent multicast (PIM) forwarding is started or restarted on an interface. In order to process the GenID
value in PIM hello messages, PIM neighbors must be running Cisco software with an implementation of PIM
that is compliant with RFC 4601.
Note
PIM neighbors that are not compliant with RFC 4601 and are unable to process GenID differences in PIM
hello messages will ignore the GenIDs.
Graceful Restart PIM Functional Overview
The figure illustrates the operations that occur after a Route Processor (RP) switchover on devices that support
the support for Graceful Restart protocol independent multicast (PIM) feature.
Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide
Prerequisites for Graceful Restart PIM
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