HP 4800G Series Configuration Manual page 990

"robustness variable minus 1" packet losses on a network. Therefore, a greater value of the robustness
variable makes the MLD querier "more robust", but results in a longer IPv6 multicast group timeout time.
Upon receiving an MLD query (general query or multicast-address-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 caused
by reports simultaneously sent by a large number of hosts when 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 messages, you can configure the last listener query
interval to fill their Maximum Response Delay field. That is to say, 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 is
launched. Otherwise, the non-querier will reset "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 startup query
interval
Configure the startup query
count
Configure the MLD query
interval
Configure the MLD querier
robustness variable
Configure the maximum
response delay for MLD
general query messages
Configure the MLD last listener
query interval
Configure the MLD other
querier present interval
Use the command...
system-view
mld
startup-query-interval interval
startup-query-count value
timer query interval
robust-count robust-value
max-response-time interval
last-listener-query-interval
interval
timer other-querier-present
interval
1-15
Remarks
—
—
Optional
For the system default, see
"Note" below.
Optional
For the system default, see
"Note" below.
Optional
125 seconds by default.
Optional
2 times by default
Optional
10 seconds by default
Optional
1 second by default
Optional
For the system default, see
"Note" below.