Configuring Mld Query And Response Parameters - HP A5500 SI Switch Series Configuration Manual

To do...
Enable the insertion of the Router-
Alert option into MLD messages

Configuring MLD query and response parameters

On startup, the MLD querier sends MLD general queries at the startup query interval, which is one-
quarter of the MLD query interval. The number of queries, or the startup query count, is user
configurable.
After startup, the MLD querier periodically sends MLD general queries at the MLD query interval to check
for IPv6 multicast group members on the network. You can modify the query interval based on the actual
condition of the network.
The MLDv1 querier sends MLD multicast-address-specific queries at the MLD last listener query interval
when it receives an MLD done message. The MLDv2 querier sends MLD multicast-address-and-source-
specific queries at the MLD last listener query interval when it receives a multicast group and multicast
source mapping change report. The number of queries, or the last listener query count, equals the
robustness variable—the maximum number of packet retransmissions.
A multicast listening host starts a timer for each IPv6 multicast group that it has joined when it receives
an MLD query—general query, multicast-address-specific query, or multicast-address-and-source-specific
query. The timer is initialized to a random value in the range of 0 to the maximum response delay
advertised in the MLD query message. When the timer decreases to 0, the host sends an MLD
membership report message to the IPv6 multicast group.
To speed up the rereponse of hosts to MLD queries and avoid simultaneous timer expirations causing
MLD report traffic bursts, you must properly 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.
Configuring MLD query and response parameters globally
Follow these steps to configure MLD query and response parameters globally:
To do...
Enter system view
Enter MLD view
Configure the MLD querier's
robustness variable
Use the command...
mld send-router-alert
Use the command...
system-view
mld
robust-count robust-value
313
Remarks
Optional
By default, MLD messages carry
the Router-Alert option.
Remarks
—
—
Optional
2 times by default.
A higher robustness variable
makes the MLD querier more
robust but results in a longer IPv6
multicast group timeout time