Protocol Independent Multicast - Cisco XR12000 Series Configuration Manual

Protocol Independent Multicast

Router C.
Figure 2: IGMPv3 Signaling
When configuring IGMP, ensure that all systems on the subnet support the same IGMP version. The router
Note
does not automatically detect Version 1 systems. Configure the router for Version 2 if your hosts do not
support Version 3.
Protocol Independent Multicast
Protocol Independent Multicast (PIM) is a routing protocol designed to send and receive multicast routing
updates. Proper operation of multicast depends on knowing the unicast paths towards a source or an RP. PIM
relies on unicast routing protocols to derive this reverse-path forwarding (RPF) information. As the name
PIM implies, it functions independently of the unicast protocols being used. PIM relies on the Routing
Information Base (RIB) for RPF information. If the multicast subsequent address family identifier (SAFI) is
configured for Border Gateway Protocol (BGP), or if multicast intact is configured, a separate multicast unicast
RIB is created and populated with the BGP multicast SAFI routes, the intact information, and any IGP
information in the unicast RIB. Otherwise, PIM gets information directly from the unicast SAFI RIB. Both
multicast unicast and unicast databases are outside of the scope of PIM.
The Cisco IOS XR implementation of PIM is based on RFC 4601 Protocol Independent Multicast - Sparse
Mode (PIM-SM): Protocol Specification. For more information, see RFC 4601 and the Protocol Independent
Multicast (PIM): Motivation and Architecture Internet Engineering Task Force (IETF) Internet draft.
Cisco IOS XR Multicast Configuration Guide for the Cisco XR12000 Series Router, Release 5.1.x
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Implementing Multicast Routing on Cisco IOS XR Software
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