Igmp Relay - IBM RackSwitch G8000 Application Manual

IGMP Relay

228
RackSwitch G8000: Application Guide
The Mrouter is learned on the incorrect trunk group
• Check link state. Trunk group 1 might be down or in STP discarding state.
• Check STP convergence.
• Check port VLAN membership.
Hosts receive multicast traffic at a lower rate than normal
Note: This behavior is expected if IPMC flood is disabled and CPU is enabled. As
soon as the IGMP/IPMC entries are installed on ASIC, the IPMC traffic
recovers and is forwarded at line rate. This applies to unregistered IPMC
traffic.
• Ensure a multicast threshold is not configured on the trunks.
RS G8000(config)# interface port <port id>
RS G8000(config-ip)# no multicast-threshold
• Check link speeds and network congestion.
The G8000 can act as an IGMP Relay (or IGMP Proxy) device that relays IGMP
multicast messages and traffic between an Mrouter and end stations. IGMP Relay
allows the G8000 to participate in network multicasts with no configuration of the
various multicast routing protocols, so you can deploy it in the network with minimal
effort.
To an IGMP host connected to the G8000, IGMP Relay appears to be an IGMP
Mrouter. IGMP Relay sends Membership Queries to hosts, which respond by
sending an IGMP response message. A host can also send an unsolicited Join
message to the IGMP Relay.
To an Mrouter, IGMP Relay appears as a host. The Mrouter sends IGMP host
queries to IGMP Relay, and IGMP Relay responds by forwarding IGMP host reports
and unsolicited Join messages from its attached hosts.
IGMP Relay also forwards multicast traffic between the Mrouter and end stations,
similar to IGMP Snooping.
You can configure up to two Mrouters to use with IGMP Relay. One Mrouter acts as
the primary Mrouter, and one is the backup Mrouter. The G8000 uses health checks
to select the primary Mrouter.