Edge-Core AS5700-54X, Cli Reference Manual, Page: 1039 / 1116

Chapter 30
| Multicast Routing Commands
PIM Multicast Routing
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The election process for each group is based on the following criteria:
■
Find all RPs with the most specific group range.
■ Select those with the highest priority (lowest priority value).
■
Compute a hash value based on the group address, RP address, priority,
and hash mask included in the bootstrap messages.
■
If there is a tie, use the candidate RP with the highest IP address.
◆
This distributed election process provides faster convergence and minimal
disruption when an RP fails. It also serves to provide load balancing by
distributing groups across multiple RPs. Moreover, when an RP fails, the
responsible RPs are re-elected on each router, and the groups automatically
distributed to the remaining RPs.
◆
To improve failover recovery, it is advisable to select at least two core routers in
diverse locations, each to serve as both a candidate BSR and candidate RP. It is
also preferable to set up one of these routers as both the primary BSR and RP.
Example
The following example configures the router to start advertising itself to the BSR as
a candidate RP for the indicated multicast groups.
Console(config)#ip pim rp-candidate interface vlan 1 group-prefix 224.0.0.0
255.0.0.0
Console(config)#end
Console#show ip pim rp mapping
PIM Group-to-RP Mappings
Groups : 224.0.0.0/8
RP address : 192.168.0.2/32
Info source : 192.168.0.2/32, via bootstrap, priority: 0
Uptime : 00:00:51
Expire : 00:01:39
Console#
ip pim spt-threshold
This command prevents the last-hop PIM router from switching to Shortest Path
Source Tree (SPT) mode. Use the
no form to allow the router to switch over to SPT
mode.
Syntax
ip pim spt-threshold infinity [ group-prefix group-address mask ]
no ip pim spt-threshold infinity
group-address - An IP multicast group address. If a group address is not
specified, the command applies to all multicast groups.
mask - Subnet mask that is used for the group address.