30 | SHOW IGMPSNOOPING ROUTERADDRESS | Patch Release Note |
Table 6: Parameters in the output of the SHOW IP ICMPREPLY command.
Parameter | Meaning |
|
|
ICMP Reply Messages | A list of ICMP configurable reply messages and whether |
| they are enabled or disabled. |
|
|
MLD Snooping
Multicast Listener Discovery (MLD) snooping enables the switch to forward IPv6 multicast traffic intelligently, instead of flooding it out all ports in the VLAN. With MLD snooping, the switch passively listens to MLD joins/reports and leaves/done messages, to identify the switch ports that have received joins and/or leaves from devices attached to them. Multicast traffic will only be forwarded to those ports. MLD snooping will also identify ports that are connected to another router or switch and forward messages out those ports appropriately.
MLD snooping is performed at Layer 2 on VLAN interfaces automatically. By default, the switch will only forward traffic out those ports with routers or IPv6 multicast listeners, therefore it will not act as a simple hub and flood all IPv6 multicast traffic out all ports. MLD snooping is independent of the MLD and Layer 3 configuration, so an IPv6 interface does not have to be attached to the VLAN, and MLD does not have to be enabled or configured.
MLD snooping is enabled by default. To disable it, use the command:
DISABLE MLDSNOOPING
Note that IPv6 multicast packets will flood the VLAN when MLD snooping is disabled.
To enable MLD snooping, use the command:
ENABLE MLDSNOOPING
To display debugging information, use the command:
ENABLE MLDSNOOPING DEBUG
This command displays the ports that are currently receiving MLD packets and the ports that are being added or taken off the switch’s multicast group membership registration.
To disable debugging, use the command:
DISABLE MLDSNOOPING DEBUG
To display information about MLD snooping, use the command:
SHOW MLDSNOOPING COUNTER
For more information, including limitations on which addresses and packet types can be snooped, see the IPv6 Multicasting chapter of the Software Reference.
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