Configuring Mld Message Options - 3Com S7906E Configuration Manual

Configurations performed in MLD view are globally effective, while configurations performed in interface
view are effective on the current interface only.
If the same function or parameter is configured in both PIM view and interface view, the configuration
performed in interface view is given priority, regardless of the configuration sequence.
Configuration Prerequisites
Before adjusting MLD performance, complete the following tasks:
Configure any IPv6 unicast routing protocol so that all devices in the domain can be interoperable
at the network layer.
Configure basic functions of MLD.
In addition, prepare the following data:
Startup query interval
Startup query count
MLD query interval
MLD querier robustness variable
Maximum response delay of MLD general query messages
MLD last listener query interval
MLD other querier present interval

Configuring MLD Message Options

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 may 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 make a decision
whether to deliver the IPv6 multicast packets to the upper-layer protocol for processing. For details
about the Router-Alert option, refer to RFC 2113.
An MLD message is processed differently depending whether it carries the Router-Alert option in the
IPv6 header:
By default, in consideration of compatibility, the device does not check the Router-Alert option, that
is, it processes all received MLD messages. In this case, the device passes MLD messages to the
upper layer protocol for processing, no matter whether the MLD messages carry the Router-Alert
option or not.
To enhance the device performance, avoid unnecessary costs, and ensure the protocol security,
you can configure the device to discard MLD messages without the Router-Alert option.
Configuring the Router-Alert option for MLD messages globally
Follow these steps to configure the Router-Alert option for MLD messages globally:
To do...
Enter system view
Enter MLD view
Use the command...
system-view
mld
1-14
Remarks
—
—