Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
Chapter 5 IGMP Configuration
5-10
5.4.2 Configuring IGMP Message Options
As IGMPv2 and IGMPv3 involve group-specific and group-and-source-specific queries,
and multicast groups change dynamically, a device cannot join all multicast groups.
Therefore, 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 details about the Router-Alert option, refer to RFC 2113.
An IGMP message is processed differently depending whether it carries the
Router-Alert option in the IP header:
z
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.
z
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.
I. Configuring IGMP packet options globally
Follow these steps to configure IGMP packet options globally:
To do...
Use the command...
Description
Enter system view
system-view
—
Enter IGMP view
igmp
—
Configure the router to
discard any IGMP
message that does not
carry the Router-Alert
option
require-router-alert
Optional
By default, the device
does not check the
Router-Alert option.
Enable the insertion of the
Router-Alert option into
IGMP messages
send-router-alert
Optional
By default, IGMP
messages carry the
Router-Alert option.
II. Configuring IGMP packet options on an interface
Follow these steps to configure IGMP packet options on an interface:
To do...
Use the command...
Description
Enter system view
system-view
—
Enter Ethernet port view
interface interface-type
interface-number
—