Configuration Guide User guide

1642 FastIron Configuration Guide
53-1002494-02
MLD snooping configuration
Enabling fast convergence
In addition to periodically sending general queries, an active (querier) device sends out general
queries when it detects a new port. However, since it does not recognize the other device port-up
event, the multicast traffic might still use the query-interval time to resume after a topology
change. Configuring fast-convergence allows the device to listen to topology change events in L2
protocols, such as spanning tree, and send general queries to shorten the convergence time.
If the L2 protocol is unable to detect a topology change, the fast-convergence feature may not work.
For example, if the direct connection between two devices switches from one interface to another,
the rapid spanning tree protocol (802.1w) considers this an optimization action, rather than a
topology change. In this case, other devices will not receive topology change notifications and will
be unable to send queries to speed up the convergence. The original spanning tree protocol does
not recognize optimization actions, and fast-convergence works in all cases.
To enable fast-convergence, enter commands such as the following.
Brocade(config)#vlan 70
Brocade(config-vlan-70)#mld-snooping fast-convergence
Syntax: mld-snooping fast-convergence
Displaying MLD snooping information
You can display the following MLD Snooping information:
• MLD Snooping error information
• Information about VLANs
• Group and forwarding information for VLANs
• MLD memory pool usage
• Status of MLD traffic
• MLD information by VLAN
Displaying MLD snooping error information
To display information about possible MLD errors, enter commands such as the following.
Brocade#show ipv6 mld-snooping error
snoop SW processed pkt: 173, up-time 160 sec
Syntax: show ipv6 mld-snooping error
The following table describes the output from the show ipv6 mld-snooping error command.
Field Description
SW processed pkt The number of IPv6 multicast packets processed by MLD snooping.
up-time The time since the MLD snooping last occurred is enabled.