Pim-Sm Overview - 3Com 5500-SI Configuration Manual

PIM-SM Overview

Configuration Procedure
This section only describes the configuration procedure for Switch_A. Follow a similar
configuration procedure for Switch_B and Switch_C.
1 Enable the multicast routing protocol.
[SW5500]multicast routing-enable
2 Enable IGMP and PIM-DM.
[SW5500]vlan 10
[SW5500-vlan10]port ethernet 1/0/2 to ethernet 1/0/3
[SW5500-vlan10]quit
[SW5500]vlan 11
[SW5500-vlan11]port ethernet 1/0/4 to ethernet 1/0/5
[SW5500-vlan11]quit
[SW5500]vlan 12
[SW5500-vlan12]port ethernet 1/0/6 to ethernet 1/0/7
[SW5500-vlan12]quit
[SW5500]interface vlan-interface 10
[SW5500-vlan-interface10]ip address 1.1.1.1 255.255.0.0
[SW5500-vlan-interface10]igmp enable
[SW5500-vlan-interface10]pim dm
[SW5500-vlan-interface10]quit
[SW5500]interface vlan-interface 11
[SW5500-vlan-interface11]ip address 2.2.2.2 255.255.0.0
[SW5500-vlan-interface11]igmp enable
[SW5500-vlan-interface11]pim dm
[SW5500-vlan-interface11]quit
[SW5500]interface vlan-interface 12
[SW5500-vlan-interface12]ip address 3.3.3.3 255.255.0.0
[SW5500-vlan-interface12]igmp enable
[SW5500-vlan-interface12]pim dm
PIM-SM (Protocol Independent Multicast, Sparse Mode) is a multicast routing
protocol, appropriate for large-scale networks (for example a WAN) where multicast
group members are relatively sparse.
PIM-SM assumes that all hosts do not need to receive multicast packets, unless there
is an explicit request for the packets. PIM-SM uses the RP (Rendezvous Point) and the
BSR (Bootstrap Router) to advertise multicast information to all PIM-SM routers, and
uses the join/prune information of the router to build the RP-rooted shared tree (RPT).
This reduces the bandwidth occupied by data packets and control packets, and
reduces the processing overhead on the router.
Multicast data flows along the shared tree to the network segments that have
multicast group members. When the data traffic is sufficient, the multicast data flow
can switch over to the SPT (Shortest Path Tree) rooted on the source to reduce
network delay. PIM-SM does not depend on the specified unicast routing protocol but
uses the present unicast routing table to perform the RPF check.
When running PIM-SM the user needs to configure candidate RPs and BSRs. The BSR
is responsible for collecting the information from the candidate RP and advertising the
information.
PIM-SM Overview 339