Configuring IGMP Snooping Proxy
Context
When IGMP is disabled on the Layer 3 device (for example, when only static multicast group is configured), there is no IGMP querier on the network to maintain multicast group membership. In this case, configure IGMP snooping proxy on a Layer 2 device, which then functions as an IGMP querier to send IGMP Query messages.
When IGMP is enabled on the network, IGMP snooping proxy can be deployed on a Layer 2 device to allow the device to send IGMP Query messages to user hosts on behalf of the Layer 3 device, and to send IGMP Report/Leave messages to the Layer 3 device on behalf of user hosts. In this case, the Layer 3 device receives fewer IGMP Report and Leave messages. This function saves bandwidth between the Layer 3 and Layer 2 devices.
A Layer 2 device configured with IGMP snooping proxy acts as a host for the upstream device and as a querier for downstream hosts.
Procedure
- Run system-view
The system view is displayed.
- Run vlan vlan-id
The VLAN view is displayed.
- Run igmp-snooping proxy
IGMP snooping proxy is enabled.
IGMP snooping proxy cannot be enabled in a VLAN if the corresponding VLANIF interface has Layer 3 multicast function (such as IGMP or PIM) enabled.
The IGMP snooping querier and IGMP message suppression functions can be enabled in the same VLAN to implement the IGMP snooping proxy function. After you configure the IGMP snooping proxy function in a VLAN, do not configure the IGMP snooping querier or IGMP message suppression function in the VLAN. For detailed configurations of IGMP snooping querier and IGMP message suppression, see (Optional) Configuring an IGMP Snooping Querier and (Optional) Suppressing Report and Leave Messages.
- If multicast VLAN replication is configured on the switch, the IGMP snooping proxy function cannot be enabled in user VLANs.
- (Optional) Run quit
Return to the system view.
- (Optional) Run interface interface-type interface-number
The interface view is displayed.
- (Optional) Run igmp-snooping proxy-uplink-port vlan vlan-id
The switch is disabled from sending IGMP Query messages to the router port.
After IGMP snooping proxy is enabled in a VLAN, the switch periodically broadcasts IGMP Query messages to all interfaces in the VLAN, including the router port. This may result in reelection of the IGMP querier. To prevent IGMP querier reelection, run this command to disable the switch from sending IGMP Query messages to the router port.