Configuration Guide User guide

FastIron Configuration Guide 1633
53-1002494-02
MLD snooping overview
The <num> parameter range is 4 to 32, in multiples of 4. If the input value is not a multiple of 4,
then it will be changed to the multiple of 4 lower than then the input value (e.g. 11 will be changed
to 8). The default hash chain length is 4. A chain length of more than 4 may affect line rate
switching.
NOTE
For this command to take effect, you must save the configuration and reload the switch.
The hardware resource limit applies only to snooping-enabled VLANs. In VLANs where snooping is
not enabled, multicast streams are switched in hardware without using any pre-installed resources.
The Brocade device supports up to 32K of MLD groups. They are produced by client membership
reports.
Configuration notes for MLD snooping
• Servers (traffic sources) are not required to send MLD memberships.
• The default MLD version is V1.
• Hardware resources are installed only when there is data traffic. If a VLAN is configured for
MLDv2, the hardware matches (S G), otherwise it matches (* G).
• You can configure the maximum number of groups and hardware-switched data streams.
• The device supports static groups applying to the entire VLAN, or to specific ports. The device
acts as a proxy to send MLD reports for the static groups when receiving queries.
• A user can configure static router ports, forcing all multicast traffic to be sent to these ports.
• All devices support fast leave for MLDv1, which stops traffic immediately to any port that has
received a leave message.
• All devices support tracking and fast leave for MLDv2, which tracks all MLDv2 clients. If the
only client on a port leaves, traffic is stopped immediately.
• An MLD device can be configured as a querier (active) or non-querier (passive). Queriers send
queries. Non-queriers listen for queries and forward them to the entire VLAN.
• Every VLAN can be independently configured as a querier or a non-querier.
• A VLAN that has a connection to an IPv6 PIM-enabled port on another router should be
configured as a non-querier. When multiple snooping devices connect together and there is no
connection to IPv6 PIM ports, only one device should be configured as the querier. If multiple
devices are configured as active, only one will continue to send queries after the devices have
exchanged queries. Refer to “Configuring queriers and non-queriers on MLD snooping-enabled
devices” on page 1634.
• An MLD device can be configured to rate-limit the forwarding of MLDv1 membership reports to
queriers.
• Because these devices use an IPv6 link-local address as the source address when sending
queries, no global address is required.
The MLD implementation allows snooping on some VLANs or on all VLANs. MLD can be enabled or
disabled independently for each VLAN. In addition, individual ports of a VLAN can be configured as
MSLv1 and MLDv2. In general, global configuration commands such as ipv6 mld-snooping... apply
to all VLANs except those with a local mld-snooping.. configuration, which supersedes the global
configuration. Configuring the version on a port or a VLAN only affects the device sent query
version. The device always processes all versions of client reports regardless of the version
configured.