Pim-Ssm Operations - Cisco XR12000 Series Configuration Manual

Internet Group Management Protocol and Multicast Listener Discovery

PIM-SSM Operations

PIM in Source-Specific Multicast operation uses information found on source addresses for a multicast group
provided by receivers and performs source filtering on traffic.
• By default, PIM-SSM operates in the 232.0.0.0/8 multicast group range for IPv4 and ff3x::/32 (where
• If SSM is deployed in a network already configured for PIM-SM, only the last-hop routers must be
• No MSDP SA messages within the SSM range are accepted, generated, or forwarded.
Restrictions for PIM-SM, PIM-SSM, and PIM-BIDIR
Interoperability with SSM
PIM-SM operations within the SSM range of addresses change to PIM-SSM. In this mode, only PIM (S,G)
join and prune messages are generated by the router, and no (S,G) RP shared tree or (*,G) shared tree messages
are generated.
IGMP Version
To report multicast memberships to neighboring multicast routers, hosts use IGMP, and all routers on the
subnet must be configured with the same version of IGMP.
A router running Cisco IOS XR Software does not automatically detect Version 1 systems. You must use the
version command in router IGMP configuration submode to configure the IGMP version.
MLD Version
To report multicast memberships to neighboring multicast routers, routers use MLD, and all routers on the
subnet must be configured with the same version of MLD.
Internet Group Management Protocol and Multicast Listener Discovery
Cisco IOS XR Software provides support for Internet Group Management Protocol (IGMP) over IPv4 and
Multicast Listener Discovery (MLD) over IPv6.
IGMP and MLD provide a means for hosts to indicate which multicast traffic they are interested in and for
routers to control and limit the flow of multicast traffic throughout the network. Routers build state by means
of IGMP and MLD messages; that is, router queries and host reports.
A set of queries and hosts that receive multicast data streams from the same source is called a multicast group.
Hosts use IGMP and MLD messages to join and leave multicast groups.
IGMP messages use group addresses, which are Class D IP addresses. The high-order four bits of a Class D
Note
address are 1110. Host group addresses can be in the range 224.0.0.0 to 239.255.255.255. The address
224.0.0.0 is guaranteed not to be assigned to any group. The address 224.0.0.1 is assigned to all systems
on a subnet. The address 224.0.0.2 is assigned to all routers on a subnet.
Cisco IOS XR Multicast Configuration Guide for the Cisco XR12000 Series Router, Release 5.1.x
8
x is any valid scope) in IPv6. To configure these values, use the ssm range command.
upgraded with Cisco IOS XR Software that supports the SSM feature.
Implementing Multicast Routing on Cisco IOS XR Software
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