Huawei AR2200-S Series Configuration Manual page 149

Huawei AR2200-S Series Enterprise Routers
Configuration Guide - Reliability
based on the link status, protocol status, and BFD status on the interface, and then reports the
interface status to the application.
Association between the BFD session status and interface status allows the system to change
the BFD status on an interface in the IFNET module accordingly when the BFD session status
of the interface changes. This function is only used on the single-hop BFD session that is bound
to an outbound interface and uses the default multicast address. This function has the following
applications:
l
l
Modifying BFD Parameters
After a BFD session is set up, you can modify BFD parameters, such as the minimum sending
interval, minimum receiving interval, or detecting mode, without affecting the current session
status.
Binding a BFD Session to a VPN Instance
On the AR2200-S, a BFD session can be bound to a VPN instance, allowing BFD Control packets
to be forwarded in a specified VPN.
BFD for VRRP
BFD detects the connectivity of links or IP routes on a network, triggering fast VRRP
switchovers.
Issue 01 (2012-01-06)
The BFD session status is associated with the status of the bound interface.
– When the BFD session goes Down, the BFD status of the bound interface goes Down,
and the interface status change is reported to the application on the interface.
When the BFD session on a trunk member interface or a VLAN member interface goes
Down, the link protocol status of the interface changes accordingly. This speeds up the
link protocol status change and route convergence on the trunk interface or VLANIF
interface.
– When the BFD session goes Up, the BFD status of the interface bound to the BFD
session also goes Up.
The BFD session status is associated with the status of a sub-interface of the main interface
bound to the BFD session.
A BFD session must be bound to a main interface.
– When the BFD session goes Down, the BFD statuses of the bound interface and all sub-
interfaces go Down, and the interface status change is reported to the application on the
sub-interfaces.
– When the BFD session goes Up, the BFD statuses of the bound interface and all sub-
interfaces go Up.
This function saves session resources in the system and provides reliability for more
applications. This function is applicable to the network where high reliability is required
and a great number of services are configured on the sub-interface, for example, a large-
scale MAN Ethernet.
NOTE
For the detailed configuration of BFD for VRRP, see the chapter "VRRP Configuration".
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
3 BFD Configuration
141