142
•
IGMPv2 snooping can process IGMPv1 and IGMPv2 messages, but flood IGMPv3 messages in the
VLAN instead of processing them.
•
IGMPv3 snooping can process IGMPv1, IGMPv2 and IGMPv3 messages.
If you change IGMPv3 snooping to IGMPv2 snooping, the system does the following:
•
Clears all IGMP snooping forwarding entries that are dynamically added.
•
Keeps static IGMPv3 snooping forwarding entries (*, G).
•
Clears static IGMPv3 snooping forwarding entries (S, G), which will be restored when IGMP
snooping is switched back to IGMPv3 snooping.
For more information about static joins, see "
To specify the version of IGMP snooping:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter VLAN view.
vlan
vlan-id
N/A
3.
Specify the version of IGMP
snooping.
igmp-snooping version
version-number
IGMPv2 snooping by default.
Configuring IGMP snooping port functions
This section describes how to configure IGMP snooping port functions.
Configuration prerequisites
Before you configure IGMP snooping port functions, complete the following tasks:
•
Enable IGMP snooping in the VLAN.
•
Configure the corresponding port groups.
•
Determine the aging timer for dynamic router ports.
•
Determine the aging timer for dynamic member ports.
•
Determine the multicast group and multicast source addresses.
Setting aging timers for dynamic ports
If an IGMP snooping-enabled router receives no IGMP general queries or PIM hello messages on a
dynamic router port when the aging timer of the port expires, this router removes the port from the router
port list.
If the IGMP snooping-enabled router receives no IGMP reports for a multicast group on a dynamic
member port when the aging timer of the port expires, this router removes the port from the multicast
forwarding entry for that multicast group.
If the memberships of multicast groups change frequently, you can set a relatively small value for the
aging timer of the dynamic member ports. If the memberships of multicast groups change rarely, you can
set a relatively large value.