Adjusting Igmp Performance - HP A8800 Configuration Manual

Adjusting IGMP performance

For the configuration tasks described in this section:
• In IGMP view, the configuration is effective on all interfaces. In interface view, the configuration is
effective on only the current interface.
If the same feature is configured in both IGMP view and interface view, the configuration 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.
•
• Determine the startup query interval.
Determine the startup query count.
•
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 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 21 13.
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 verify the Router-Alert option.
•
It processes all the IGMP messages that it received. In this case, IGMP messages are directly passed
to the upper layer protocol, 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 Router-Alert option handling methods globally
Step
1. Enter system view.
Command
system-view
93
Remarks
N/A