H3C Technologies H3C SecPath F1000-E - Manual (Page 45)

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NOTE:
For the configuration tasks described in this section:
• Configurations performed in IGMP view are effective on all interfaces, while configurations performed
in interface view are effective on the current interface only.
• If the same feature is configured in both IGMP view and interface view, the configuration performed in
interface view is given priority, regardless of the configuration sequence.
Configuration Prerequisites
Before adjusting IGMP performance, complete the following tasks:
• Configure any unicast routing protocol so that all devices in the domain are interoperable at the
network layer.
• Configure basic functions of IGMP
Before adjusting IGMP performance, prepare the following data:
• Startup query interval
• Startup query count
• IGMP general query interval
• IGMP querier’s robustness variable
• Maximum response time for IGMP general queries
• IGMP last-member query interval
• 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 receiving a multicast packet but unable to locate the outgoing interface for
the destination multicast group, an IGMP router needs to 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,
namely it processes all the IGMP messages it received. In this case, IGMP messages are directly
passed to the upper layer protocol, no matter whether the IGMP messages carry the Router-Alert
option or not.
• To enhance the device performance and avoid unnecessary costs, and also for the consideration of
protocol security, you can 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... Use the command... Remarks
Enter system view system-view —