H3C Technologies H3C S7500E Series Switches - Manual (Page 122)

5-15
To do... Use the command... Remarks
Enable insertion of the
Router-Alert option into IGMP
messages
send-router-alert
Optional
By default, IGMP messages
carry the Router-Alert option.
Configuring IGMP packet options on an interface
Follow these steps to configure IGMP packet options 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 IGMP message that
does not carry the Router-Alert
option
igmp require-router-alert
Optional
By default, the device does not
check the Router-Alert option.
Enable insertion of the
Router-Alert option into IGMP
messages
igmp send-router-alert
Optional
By default, IGMP messages
carry the Router-Alert option.
Configuring IGMP Query and Response Parameters
The IGMP querier’s robustness variable defines the maximum number of attempts for
transmitting IGMP general queries, group-specific queries, or group-and-source-specific
queries in case of packet loss due to network problems. A greater value of the robustness
variable makes the IGMP querier “more robust”, but results in longer multicast group timeout
time.
On startup, the IGMPv1/v2/v3 querier sends “startup query count” IGMP general queries at the
“startup query interval”.
The IGMPv1/v2/v3 querier periodically sends IGMP general queries at the “IGMP general query
interval” to determine whether any multicast group member exists on the network. You can tune
the IGMP general query interval based on actual condition of the network.
Upon receiving an IGMP leave message, the IGMPv2 querier sends “last-member query count”
IGMP group-specific queries at the “IGMP last-member query interval”; upon receiving an IGMP
report that tells relation changes between multicast groups and multicast sources, the IGMPv3
querier sends “last-member query count” IGMP group-and-source-specific queries at the “IGMP
last-member query interval”. The value of the “last-member query count” equals the value of the
robustness variable.
Upon receiving an IGMP query (general query, group-specific query, or
group-and-source-specific query), a host starts a delay timer for each multicast group it has