Cisco ASR 9000 Series Software Manual page 8

Protocol Independent Multicast
IGMP Routing Example
Figure 2: IGMPv3 Signaling, on page 8
to group 239.1.1.1. The receiver wants to receive traffic addressed to group 239.1.1.1 from source 10.0.0.1
but not from source 10.0.1.1. The host must send an IGMPv3 message containing a list of sources and groups
(S, G) that it wants to join and a list of sources and groups (S, G) that it wants to leave. Router C can now use
this information to prune traffic from Source 10.0.1.1 so that only Source 10.0.0.1 traffic is being delivered
to
Router C.
Figure 2: IGMPv3 Signaling
Note When configuring IGMP, ensure that all systems on the subnet support the same IGMP version. The router
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.
Cisco ASR 9000 Series Aggregation Services Router Multicast Configuration Guide, Release 5.1.x
8
Implementing Layer-3 Multicast Routing on Cisco IOS XR Software
illustrates two sources, 10.0.0.1 and 10.0.1.1, that are multicasting