igmp-snooping report-suppress (VLAN view)
Function
The igmp-snooping report-suppress command enables suppression of IGMP Report and Leave messages in a VLAN.
The undo igmp-snooping report-suppress command disables suppression of IGMP Report and Leave messages in a VLAN.
By default, IGMP Report and Leave message suppression is disabled in a VLAN.
Usage Guidelines
Usage Scenario
- When joining a multicast group, a host sends a Report message. When a multicast group has multiple members in a VLAN, the Layer 3 device receives duplicate Report messages from the member hosts.
- When receiving an IGMP General Query message, a host sends a Report message. Hosts use a timer to suppress duplicate Report messages on the same network segment. However, if the timer values on hosts are the same, the Layer 3 device can still receive duplicate Report messages.
- A host running IGMPv2 or IGMPv3 sends a Leave message when leaving a multicast group. When a multicast group has multiple members in a VLAN, the Layer 3 device receives duplicate Leave messages from the member hosts.
- When the first member joins a multicast group or a host sends a Report message in response to an IGMP Query message, the Layer 2 device forwards a Report message to the upstream device. The upstream can create or maintain the matching forwarding entry based on the Report message.
- When the last member of a multicast group leaves the group, the Layer 2 device forwards a Leave message to the upstream device. The upstream device then deletes the matching forwarding entry.
This reduces the number of IGMP messages on the network.
Prerequisites
IGMP snooping has been enabled globally using the igmp-snooping enable (system view) command.
Configuration Impact
The configuration takes effect only after you run the igmp-snooping enable (VLAN view) command to enable IGMP snooping in the VLAN.
IGMP message suppression cannot be configured in a VLAN if the corresponding VLANIF interface has IGMP enabled.
If multicast VLAN replication is configured on the wireless access controller, the IGMP message suppression function cannot be enabled in user VLANs.
- The device can suppress duplicate Report messages even when IGMP message suppression is disabled. The default suppression time is 10 seconds. To change the suppression time, run the igmp-snooping suppress-time suppress-time command. If the suppress-time is set to 0, all the membership packets are forwarded immediately.
