HP VPN Firewall Appliances Network Management Configuration Guide

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Command Remarks
4. Enable the insertion of the Router-Alert
option into MLD messages.
mld send-router-alert
By default, MLD messages carry
the Router-Alert option.
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 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
Ste
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Command Remarks
1. Enter system view.
system-view N/A
2. Enter MLD view.
mld N/A