Configuring IGMP Snooping
To support selective Multicast forwarding (IPv4), Bridge Multicast filtering must be enabled (in the Properties page), and IGMP Snooping must be enabled globally and for each relevant VLAN (in the IGMP Snooping page).
Additional Information
By default, a Layer 2 switch forwards Multicast frames to all ports of the relevant VLAN, essentially treating the frame as if it were a Broadcast. With IGMP Snooping the switch forwards Multicast frames to ports that have registered Multicast clients.
NOTE The switch supports IGMP Snooping only on static VLANs. It does not support IGMP Snooping on dynamic VLANs.
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:
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 Data Base.
To enable IGMP Snooping and identify the switch as an IGMP Snooping Querier on a VLAN:
- Click Multicast > IGMP Snooping. The IGMP Snooping page opens.
- Enable or disable the IGMP Snooping status.
When IGMP Snooping is enabled globally, the device monitoring network traffic can determine which hosts have requested to receive Multicast traffic.
The switch only performs IGMP Snooping if both IGMP snooping and Bridge Multicast filtering are enabled.
- Select a VLAN, and click Edit. The Edit IGMP Snooping page opens.
- Enter the parameters.
- VLAN ID--Select the VLAN ID on which IGMP snooping is defined.
- IGMP Snooping Status--Enable or disable the monitoring of network traffic for the selected VLAN.
- Operational IGMP Snooping Status--Displays the current status of the IGMP Snooping for the selected VLAN.
- MRouter Ports Auto Learn--Enable or disable auto learning of the ports to which the Mrouter is connected.
- Query Robustness--Enter the Robustness Variable value to be used if this switch is the elected querier.
- Operational Query Robustness--Displays the robustness variable sent by the elected querier.
- Query Interval--Enter the interval between the General Queries to be used if this switch is the elected querier.
- Operational Query Interval--The time interval in seconds between General Queries sent by the elected querier.
- Query Max Response Interval--Enter the delay used to calculate the Maximum Response Code inserted into the periodic General Queries.
- Operational Query Max Response Interval--Displays the Query Max Response Interval included in the General Queries sent by the elected querier.
- Last Member Query Counter--Enter the number of IGMP Group-Specific Queries sent before the switch assumes there are no more members for the group, if the switch is the elected querier.
- Operational Last Member Query Counter--Displays the operational value of the Last Member Query Counter.
- Last Member Query Interval--Enter the Maximum Response Delay to be used if the switch cannot read Max Response Time value from group-specific queries sent by the elected querier.
- Operational Last Member Query Interval--Displays the Last Member Query Interval sent by the elected querier.
- Immediate Leave--Enable Immediate Leave to decrease the time it takes to block a Multicast stream sent to a member port when an IGMP Group Leave message is received on that port.
- Click Apply. The Running Configuration file is updated..