H3C Technologies H3C S7500E Series Switches - Manual (Page 336)

12-16
To do… Use the command… Remarks
Enable the insertion of the
Router-Alert option into MLD
messages
send-router-alert
Optional
By default, MLD messages carry
the Router-Alert option.
Configuring the Router-Alert option on an interface
Follow these steps to configure the Router-Alert option on an interface:
To do… Use the command… Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Configure the interface to discard
any MLD message without the
Router-Alert option
mld require-router-alert
Optional
By default, the device does not
check MLD messages for the
Router-Alert option.
Enable the insertion of the
Router-Alert option into MLD
messages
mld send-router-alert
Optional
By default, MLD messages carry
the Router-Alert option.
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.
Upon 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”; upon 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.
Upon receiving an MLD query (general query, multicast-address-specific query, or
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