H3C Technologies H3C S10500 Series Switches - Manual (Page 353)

338
multicast groups that have no members on the local subnet. In this case, the Router-Alert option carried
in the IPv6 multicast packets is useful for the router to determine whether to deliver the IPv6 multicast
packets to the upper-layer protocol for processing. For more information about the Router-Alert option,
see RFC 2113.
An MLD message is processed differently depending on whether it carries the Router-Alert option in the
IPv6 header, as follows:
• For compatibility, the device by default ignores the Router-Alert option and processes all received
MLD messages, no matter whether the MLD messages carry the Router-Alert option or not.
• To enhance device performance, avoid unnecessary costs, and ensure protocol security, configure
the device to discard MLD messages that do not carry the Router-Alert option.
Configuring the Router-Alert option for MLD messages globally
Follow these steps to configure the Router-Alert option for MLD messages globally:
To do… Use the command… Remarks
Enter system view system-view —
Enter MLD view mld —
Configure the interface to discard
any MLD message without the
Router-Alert option
require-router-alert
Required
By default, the device does not
check MLD messages for the
Router-Alert option.
Enable the insertion of the
Router-Alert option into MLD
messages
send-router-alert
Required
By default, MLD messages carry
the Router-Alert option.
Configuring the Router-Alert option on an interface
Follow these steps to configure the Router-Alert option on an interface:
To do… Use the command… Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Configure the interface to discard
any MLD message without the
Router-Alert option
mld require-router-alert
Required
By default, the device does not
check MLD messages for the
Router-Alert option.
Enable the insertion of the
Router-Alert option into MLD
messages
mld send-router-alert
Required
By default, MLD messages carry
the Router-Alert option.
Configuring MLD query and response parameters
On startup, the MLD querier sends MLD general queries at the startup query interval, which is
one-quarter of the MLD query interval. The number of queries, or the startup query count, is user
configurable.