igmp-snooping suppress-time
Function
The igmp-snooping suppress-time command sets the IGMP message suppression time in a VLAN.
The undo igmp-snooping suppress-time command restores the default IGMP message suppression time in a VLAN.
By default, the IGMP message suppression time is 10 seconds.
Usage Guidelines
Usage Scenario
To reduce the IGMP messages sent from a Layer 2 device to the upstream Layer 3 device and protects the Layer 3 device from attacks, enable the Layer 2 device to suppress IGMP Report and IGMP Leave messages sent by hosts in a VLAN. After this function is enabled, the Layer 2 device processes IGMP Report and IGMP Leave messages as follows:
- After receiving an IGMP Report/Leave message and forwarding the message, the Layer 2 device does not forward the same type of messages to the router port within the suppression time.
- If the Layer 2 device receives an IGMP General Query message or Group-Specific message, it does not suppress the first IGMP Report message that responds to the General Query message. In addition, the Layer 2 device resets the suppression timer when receiving the first IGMP Report message.
Prerequisites
IGMP snooping has been enabled globally using the igmp-snooping enable (system view) command.
Follow-up Procedure
Run the igmp-snooping max-response-time command to set the maximum response time for General Query messages. It is recommended that the suppression time be the same as the maximum response time for IGMP Query messages in a VLAN.
Precautions
The configuration takes effect only after you run the igmp-snooping enable (VLAN view) command to enable IGMP snooping in the VLAN.
The configured suppression time is invalid for IGMPv3 messages.
