HP 6125G HP 6125G & 6125G/XG Blade Switches IP Multicast Configuration - Page 97

Configuring Router-Alert option handling methods

Page 97 highlights

• Determine the IGMP last-member query interval. • Determine the other querier present interval. • Determine the DSCP value for IGMP messages. Configuring Router-Alert option handling methods 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 use 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 switch does not verify 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 switch performance and avoid unnecessary costs, and also for the consideration of protocol security, you can configure the switch to discard IGMP messages that do not carry the Router-Alert option. Configuring Router-Alert option handling methods globally Step 1. Enter system view. 2. Enter IGMP view. 3. Configure the router to discard any IGMP message that does not carry the Router-Alert option. 4. Enable insertion of the Router-Alert option into IGMP messages. Command system-view igmp require-router-alert send-router-alert Configuring Router-Alert option handling methods on an interface Remarks N/A N/A By default, the switch does not check the Router-Alert option. By default, IGMP messages carry the Router-Alert option. Step Command 1. Enter system view. system-view 2. Enter interface view. interface interface-type interface-number 3. Configure the interface to discard any IGMP message that does not carry the Router-Alert option. igmp require-router-alert 4. Enable insertion of the Router-Alert option into IGMP igmp send-router-alert messages. 86 Remarks N/A N/A By default, the switch does not check the Router-Alert option. By default, IGMP messages carry the Router-Alert option.

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86
Determine the IGMP last-member query interval.
Determine the other querier present interval.
Determine the DSCP value for IGMP messages.
Configuring Router-Alert option handling methods
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 use 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 switch does not verify 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 switch performance and avoid unnecessary costs, and also for the consideration of
protocol security, you can configure the switch to discard IGMP messages that do not carry the
Router-Alert option.
Configuring Router-Alert option handling methods globally
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter IGMP view.
igmp
N/A
3.
Configure the router to
discard any IGMP message
that does not carry the
Router-Alert option.
require-router-alert
By default, the switch does not
check the Router-Alert option.
4.
Enable insertion of the
Router-Alert option into IGMP
messages.
send-router-alert
By default, IGMP messages carry
the Router-Alert option.
Configuring Router-Alert option handling methods on an interface
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Configure the interface to
discard any IGMP message
that does not carry the
Router-Alert option.
igmp require-router-alert
By default, the switch does not
check the Router-Alert option.
4.
Enable insertion of the
Router-Alert option into IGMP
messages.
igmp send-router-alert
By default, IGMP messages carry
the Router-Alert option.