KB.15.15

• Ports with multicast routers

Ports on the VLAN that lead toward multicast routers (if any).

• Multicast group address information

For each active group on the VLAN, including:

• Multicast group address.

• Type of tracking for multicast joins: standard or filtered.

• If MLD snooping is enabled, port-level tracking results in filtered groups.

• If MLD snooping is not enabled, joins result in standard groups being tracked by this

device.

• In addition, if hardware resources for multicast filtering are exhausted, new joins

may result in standard groups even though MLD snooping is enabled.

• MLD version number (MLDv2 display only)

• Mode—INCLUDE or EXCLUDE (MLDv2 only): when INCLUDE is displayed, the host

has requested specific source/group pairs. When EXCLUDE is displayed, the host

has requested all sources for a group except for a specified list of sources to exclude.

• Uptime

The length of time the group has been joined

• Expiry time

Time until the group expires if no joins are seen.

• The ports that have joined the multicast group.

The group addresses that are listed typically result from several network functions. In the example

Example 119 (page 182), several of the addresses at the top of the list for each VLAN are IANA

well-known addresses (see www.iana.org/assignments/ipv6-multicast-addresses); the addresses

in the form of ff02::1:ffxx:xxxx are solicited-node multicast addresses (used in IPv6 ND);

and the addresses beginning with ff3e are group addresses used by listeners to streaming video

feeds.

Current MLD configuration

The following information applies to all MLD-enabled VLANs:

• Control unknown multicast

If this is set to YES, any IPv6 multicast packets that are not joined by an MLD host are sent

only to ports that have detected a multicast router or ports that are administratively forwarded.

If this is set to NO (or if MLD snooping is disabled), unjoined IPv6 multicast packets are flooded

out all ports in the VLAN.

• Forced fast leave timeout

Interval between an address-specific query and a forced fast leave (assuming no response),

in tenths of seconds.

• For each VLAN that has MLD enabled:

Whether MLD is enabled on the VLAN (default NO, but the VLAN will not show up on

this list unless MLD is enabled).

•

• Whether the switch can act as querier for the VLAN (default YES).

• the MLD version (1 or 2)

84 Multicast Listener Discovery (MLD) Snooping