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Adjusting MLD performance
This section describes how to adjust MLD performance.
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.
•
Determine the DSCP value for MLD messages.
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.
•
To enhance device performance, avoid unnecessary costs, and ensure protocol security,
configure the device to discard MLD messages that do not carry the Router-Alert option.
Configuring Router-Alert option handling methods globally
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter public network MLD
view or VPN instance MLD
view.
mld
[
vpn-instance
vpn-instance-name
]
N/A
3.
Configure the interface to
discard any MLD message
without the Router-Alert
option.
require-router-alert
By default, the device does not
examine MLD messages for the
Router-Alert option.
4.
Enable the insertion of the
Router-Alert option into MLD
send-router-alert
By default, MLD messages carry
the Router-Alert option.
