Determine the IGMP general query interval
•
Determine the IGMP querier's robustness variable
•
Determine the maximum response time for IGMP general queries
•
Determine the IGMP last-member query interval
•
Determine the other querier present interval
•
Configuring IGMP message options
IGMP queries include group-specific queries and group-and-source-specific queries, and multicast groups
change dynamically, so a device cannot maintain the information for all multicast sources and groups.
For this reason, when an IGMP router receives a multicast packet but cannot locate the outgoing
interface for the destination multicast group, it must leverage the Router-Alert option to pass the multicast
packet to the upper-layer protocol for processing. For more information about the Router-Alert option,
see RFC 2113.
An IGMP message is processed differently depending on whether it carries the Router-Alert option in the
IP header:
By default, for the consideration of compatibility, the device does not check the Router-Alert option
•
but processes all the IGMP messages that it received. In this case, IGMP messages are directly
passed to the upper-layer protocol, whether or not the IGMP messages carry the Router-Alert
option.
To enhance the device performance and avoid unnecessary costs, and also for the consideration of
•
protocol security, configure the device to discard IGMP messages that do not carry the Router-Alert
option.
Configuring IGMP packet options globally
Follow these steps to configure IGMP packet options globally:
To do...
Enter system view
Enter public network IGMP view
or VPN instance IGMP view
Configure the router to discard
any IGMP message that does not
carry the Router-Alert option
Enable insertion of the Router-Alert
option into IGMP messages
Configuring IGMP packet options on an interface
Follow these steps to configure IGMP packet options on an interface:
To do...
Enter system view
Enter interface view
Use the command...
system-view
igmp [ vpn-instance vpn-instance-
name ]
require-router-alert
send-router-alert
Use the command...
system-view
interface interface-type interface-
number
95
Remarks
—
—
Optional
By default, the device does not
check the Router-Alert option.
Optional
By default, IGMP messages carry
the Router-Alert option.
Remarks
—
—