Installation guide

Network Setup 4-161
6. Review to the following to discern whether an existing snoop configuration requires revision.
7. Optionally, select a VLAN Index from amongst those listed, and select Edit to revise the Snoop Enable,
Unknown Multicast Forward, Learning Mode and Multicast Router Ports.
8. Select OK to save the edits to the IGMP configuration. Selecting Cancel reverts the IGMP snooping
configuration to its previous settings.
4.11.2 IGMP Snoop Querier Configuration
The IGMP snoop querier functionality is used in absence of a multicast router in networks where there is a
multicast streaming server and multicast listener hosts, but no IGMP querier. For IGMP snooping to work,
periodic IGMP general queries are required so multicast group memberships are refreshed by interested
clients by replying to IGMP reports for the IGMP queries received. This feature can also be enabled under
circumstances where the user wants to accommodate a query loss due to a multicast router being down or
a query loss in the network. The present timeout is used to detect query loss and activate the switch querier.
Switch topology changes are roaming clients. Joining or going away is handled by proxy querying (which is
part of IGMP snoop functionality not the querier. On wired side, all multicast packets are flooded, so there is
no need for a proxy query or detecting such changes.
Vlan Index Lists the VLAN interfaces upon which snooping and unknown multicast forward is
enabled or disabled
Snoop Enable Displays whether IGMP snooping is enabled/disabled on the VLAN Index listed.
Unknown Multicast
Forward
Displays whether unknown multicast traffic is enabled/disabled on the VLAN Index
listed.
Learning Mode Displays the learning mode the switch uses to listen to messages to detect router
ports with IGMP snooping. Modes include:
pimDvmrp(1) - Protocol Independent Multicast and Distance Vector
static - Static entry
Mulitcast Router Ports Displays the name of the multicast router port discovered as part of the snooping
process. If no port has been detected, a No port Discovered Yet message displays.