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To speed up the response of hosts to MLD queries and avoid simultaneous timer expirations causing MLD
report traffic bursts, you must correctly set the maximum response delay:
•
For MLD general queries, the maximum response delay is set by the
max-response-time
command.
•
For MLD multicast-address-specific query and multicast-address-and-source-specific query
messages, the maximum response delay equals the last listener query interval.
When multiple multicast routers exist on the same subnet, the MLD querier is responsible for sending MLD
query messages. If a non-querier router receives no MLD query from the querier when the other querier
present interval expires, it considers the querier as having failed and starts a new querier election.
Otherwise, the non-querier resets the other querier present timer.
When you configure MLD query and response parameters, following these guidelines:
•
To avoid frequent MLD querier changes, set the other querier present interval greater than the MLD
query interval.
•
To avoid incorrect multicast group member removals, set the MLD query interval greater than the
maximum response delay for MLD general queries.
Configuring MLD query and response parameters globally
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter MLD view.
mld
N/A
3.
Configure the MLD querier's
robustness variable.
robust-count
robust-value
2 by default.
A higher robustness variable
makes the MLD querier more
robust but results in a longer IPv6
multicast group timeout time.
4.
Configure the startup query
interval.
startup-query-interval
interval
By default, the startup query
interval is one-quarter of the "MLD
query interval."
5.
Configure the startup query
count.
startup-query-count
value
By default, the startup query count
is the same as the MLD querier's
robustness variable.
6.
Configure the MLD query
interval.
timer query
interval
125 seconds by default.
7.
Configure the maximum
response delay for MLD
general query messages.
max-response-time
interval
10 seconds by default.
8.
Configure the MLD last
listener query interval.
last-listener-query-interval
interval
1 second by default.
9.
Configure the MLD other
querier present interval.
timer other-querier-present
interval
By default, the other querier
present interval is determined by
the formula "Other querier present
interval (in seconds) = [ MLD query
interval ] × [ MLD querier's
robustness variable ] + [ maximum
response delay for MLD general
query ] / 2".
