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Step Command
Remarks
3.
Configure the maximum number of
IPv6 multicast groups that the
interface can join.
mld group-limit
limit
The default value varies with
devices. For more
information, see
IP Multicast
Command Reference
.
This configuration only limits
the number of IPv6 multicast
groups that the interface
dynamically joins.
Adjusting MLD performance
For the configuration tasks in this section, the following rules apply:
•
The configurations made in MLD view are effective on all interfaces. The configurations in interface
view are effective only on the current interface.
•
A configuration made in interface view always has priority over the same configuration in MLD view,
regardless of the configuration sequence.
Configuration prerequisites
Before adjusting MLD performance, complete the following tasks:
•
Enable IPv6 forwarding and configure an IPv6 unicast routing protocol so that all devices in the
domain can be interoperable at the network layer.
•
Configure basic MLD functions.
•
Determine the startup query interval.
•
Determine the startup query count.
•
Determine the MLD query interval.
•
Determine the MLD querier's robustness variable.
•
Determine the maximum response delay of MLD general query messages.
•
Determine the MLD last listener query interval.
•
Determine the MLD other querier present interval.
Configuring Router-Alert option handling methods
MLD queries include multicast-address-specific queries and multicast-address-and-source-specific queries,
and IPv6 multicast groups change dynamically, so a device cannot maintain the information for all IPv6
multicast sources and groups. Therefore, a router might receive IPv6 multicast packets addressed to IPv6
multicast groups that have no members on the local subnet. In this case, the Router-Alert option carried
in the IPv6 multicast packets is useful for the router to determine whether to deliver the IPv6 multicast
packets to the upper-layer protocol for processing. For more information about the Router-Alert option,
see RFC 2113.
An MLD message is processed differently depending on whether it carries the Router-Alert option in the
IPv6 header, as follows:
•
For compatibility, the device by default ignores the Router-Alert option and processes all received
MLD messages, no matter whether the MLD messages carry the Router-Alert option or not.