System information

Configuring Multicast Forwarding
Configuring IGMP Snooping
Cisco Small Business 200 Series Smart Switch Administration Guide 134
14
When IGMP Snooping is enabled globally or on a VLAN, all IGMP packets are
forwarded to the CPU. The CPU analyzes the incoming packets, and determines
the following:
• Which ports are asking to join which Multicast groups on what VLAN.
• Which ports are connected to Multicast routers (Mrouters) that are
generating IGMP queries.
• Which ports are receiving PIM, DVMRP, or IGMP query protocols.
These are displayed on the
IGMP Snooping Page .
Ports asking to join a specific Multicast group issue an IGMP report that specifies
which group(s) the host wants to join. This results in the creation of a forwarding
entry in the Multicast forwarding database.
To enable IGMP Snooping on a VLAN:
STEP 1 Click Multicast > IGMP Snooping. The IGMP Snooping Page opens.
The IGMP Snooping Table displays the IGMP snooping information for the VLANs
on the switch. The columns are described in STEP 4.
STEP 2 Check Enable for IGMP Snooping status.
IGMP Snooping Status globally enables the device monitoring network traffic to
determine which hosts have requested to receive Multicast traffic. The switch
performs IGMP Snooping if IGMP snooping and Bridge Multicast filtering are both
enabled.
STEP 3 Select a VLAN, and click Edit. The Edit IGMP Snooping Page opens.
There should be only one IGMP Querier in a network. The switch supports
standards-based IGMP Querier election. The following values are used when the
querier message does not supply them (for IGMPv1/v2).
STEP 4 Enter the parameters.
• VLAN ID—Select the VLAN ID where IGMP snooping is defined.
• IGMP Snooping Status—Enable or disable the monitoring of network traffic
to determine which hosts have asked to be sent Multicast traffic. The switch
performs IGMP snooping only if IGMP snooping and Bridge Multicast filtering
are both enabled.