Understanding The Mldv2 Snooping Querier; Default Mldv2 Snooping Configuration; Mldv2 Snooping Configuration Guidelines And Restrictions - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Chapter 26 Configuring MLDv2 Snooping for IPv6 Multicast Traffic

Understanding the MLDv2 Snooping Querier

Use the MLDv2 snooping querier to support MLDv2 snooping in a VLAN where PIM and MLDv2 are
not configured because the multicast traffic does not need to be routed.
In a network where IP multicast routing is configured, the IP multicast router acts as the MLDv2 querier.
If the IP-multicast traffic in a VLAN only needs to be Layer 2 switched, an IP-multicast router is not
required, but without an IP-multicast router on the VLAN, you must configure another switch as the
MLDv2 querier so that it can send queries.
When enabled, the MLDv2 snooping querier sends out periodic MLDv2 queries that trigger MLDv2
report messages from the switch that wants to receive IP multicast traffic. MLDv2 snooping listens to
these MLDv2 reports to establish appropriate forwarding.
You can enable the MLDv2 snooping querier on all the Catalyst 6500 series switches in the VLAN, but
for each VLAN that is connected to switches that use MLDv2 to report interest in IP multicast traffic,
you must configure at least one switch as the MLDv2 snooping querier.
You can configure a switch to generate MLDv2 queries on a VLAN regardless of whether or not IP
multicast routing is enabled.

Default MLDv2 Snooping Configuration

Table 26-3
Table 26-3
Feature
MLDv2 snooping querier
MLDv2 snooping
Multicast routers
MLDv2 report suppression
MLDv2 snooping router learning
method
Fast-Leave Processing
MLDv2 Explicit Host Tracking

MLDv2 Snooping Configuration Guidelines and Restrictions

When configuring MLDv2 snooping, follow these guidelines and restrictions:
•
•
•
OL-11439-03
shows the default MLDv2 snooping configuration.
MLDv2 Snooping Default Configuration
MLDv2 is derived from Internet Group Management Protocol version 3 (IGMPv3). MLDv2
protocol operations and state transitions, host and router behavior, query and report message
processing, message forwarding rules, and timer operations are exactly same as IGMPv3. See
draft-vida-mld-v2.02.txt for detailed information on MLDv2 protocol.
MLDv2 protocol messages are Internet Control Message Protocol version 6 (ICMPv6) messages.
MLDv2 message formats are almost identical to IGMPv3 messages.
Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
Default Values
Disabled
Enabled
None configured
Enabled
Learned automatically through PIM or MLDv2 packets
Enabled
Enabled
Default MLDv2 Snooping Configuration
26-7