Configuring Mld Query And Response Parameters - HP A6600 Configuration Manual

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

Configuring MLD query and response parameters

The MLD querier's robustness variable defines the maximum number of attempts for transmitting MLD
general queries, multicast-address-specific queries, or multicast-address-and-source-specific queries in
case of packet loss due to network problems. A greater value of the robustness variable makes the MLD
querier "more robust", but results in a longer IPv6 multicast group timeout time.
On startup, the MLDv1/v2 querier sends "startup query count" MLD general queries at the "startup query
interval", which is 1/4 of the "MLD query interval".
The MLDv1/v2 querier periodically sends MLD general queries at the "MLD query interval" to determine
whether any IPv6 multicast group member exists on the network. You can modify the query interval based
on the actual condition of the network.
After receiving an MLD done message, the MLDv1 querier sends "last listener query count" MLD
multicast-address-specific queries at the "MLD last listener query interval". After receiving an MLD report
that tells relation changes between IPv6 multicast groups and IPv6 multicast sources, the MLDv2 querier
sends "last listener query count" MLD multicast-address-and-source-specific queries at the "MLD last
listener query interval". The value of the "last listener query count" equals the value of the robustness
variable.
After receiving
multicast-address-and-source-specific query) message, a host starts a timer for each IPv6 multicast group it
has joined. The timer is initialized to a random value in the range of 0 to the maximum response delay
(the host obtains the maximum response delay from the Maximum Response Delay field in the MLD query
message it received). When the timer value drops to 0, the host sends an MLD membership report
message to the corresponding IPv6 multicast group.
Proper setting of the maximum response delay of MLD query messages not only allows hosts to respond to
MLD query messages quickly, but also avoids bursts of MLD traffic on the network. Such bursts can occur
when a large number of hosts send reports at the same time when the corresponding timers expire
simultaneously.
For MLD general queries, you can configure the maximum response delay to fill their Maximum
•
Response Delay field.
For MLD multicast-address-specific query and multicast-address-and-source-specific query messages,
•
you can configure the last listener query interval to fill their Maximum Response Delay field. That is,
the maximum response time of MLD general query messages 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 within the other querier
present interval, it will assume that the querier has failed and a new querier election process begins.
Otherwise, the non-querier will reset the other querier present timer.
Configuring MLD query and response parameters globally
To do...
1. Enter system view.
Use the command...
mld send-router-alert
an MLD query (general
Use the command...
system-view
Remarks
Optional.
By default, MLD messages carry
the Router-Alert option.
query, multicast-address-specific
Remarks
—
282
query, or