Huawei AR2200-S Series Configuration Manual page 173

Huawei AR2200-S Series Enterprise Routers
Configuration Guide - Reliability
Applicable Environment
As shown in
the middle of the physical link resides Layer 2 transmission devices, so the physical link is
divided into multiple segments. It takes a long period for the two devices on both ends of the
link to detect a link fault. The directly connected route spends al long time on becoming
ineffective, and network interruption lasts for a long period.
Figure 3-2 A transit device exists on the link
RouterA
To speed up route convergence, associate the BFD status and interface status so that the BFD
session status change will trigger the protocol status change on the interface.
When BFD detects a fault, it enters the Down state, and then the bound interface also enters the
BFD_Down state. The direct route of the interface is deleted from the routing table; however,
the BFD packets are still forwarded.
Pre-Configuration Tasks
Before associating BFD status with interface status, complete the following task:
l
Procedure
Step 1 Run:
system-view
The system view is displayed.
Step 2 Run:
bfd
BFD is globally enabled and the BFD view is displayed.
Step 3 Run:
default-ip-address ip-address
Issue 01 (2012-01-06)
Figure 3-2, RouterA and RouterB are connected on the same network segment. In
NOTE
l Before the BFD status is associated with the interface status, the BFD configurations on two routers
must be correct and matched. If the BFD status on the local interface is Down, check whether the BFD
configuration on the remote end is correct and the BFD session is shut down.
l If the BFD session must be synchronized to an interface immediately, ensure that the BFD
configurations on the two routers are the same and run the shutdown and undo shutdown commands
on the BFD session. When the undo shutdown command is executed for a BFD session, a BFD session
detection timer is started. If the BFD session becomes Up through negotiation before the timer times
out, the BFD session notifies an interface of the Up state. Otherwise, the BFD session considers the
link faulty and notifies the interface of the Down state. The status of a BFD session and the status of
an interface are synchronized in real time.
Connecting interfaces properly
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3 BFD Configuration
RouterB
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