Huawei AR2200-S Series Configuration Manual page 18

Huawei AR2200-S Series Enterprise Routers
Configuration Guide - Reliability
link is leased as the backup link. After association between interface backup and BFD is
configured on the backup interface of RouterA, if the BFD session detects that the route on the
primary link is unreachable, it requests RouterA to start the backup interface Interface2 to
transmit services. When the BFD session detects that the original primary link is restored,
RouterA switches services back.
The routers on both ends of the link must support BFD and apply to the scenario that requires
fast fault switchover and high network stability and real-time performance.
When the BFD session detects that the primary link is working properly, backup links do not
transmit services. When the BFD session detects that the primary link is unreachable, a backup
interface is started.
Figure 1-5 Networking diagram of association between interface backup and BFD
NOTE
Assume that the primary and backup links use static routes. When the primary link is faulty, data traffic
will be lost because routes cannot be switched immediately. To speed up data traffic switching, set the
route priority of the backup link to be higher than that of the primary link or configure BFD for static routes.
When the BFD session detects that the route on the primary link is unreachable, it deletes the static route
corresponding to the primary link from the routing table. For details, see Configuration Guide - IP Routing.
Pre-Configuration Tasks
Before configuring association between interface backup and BFD, complete the following
tasks:
l
l
Procedure
1.
Issue 01 (2012-01-06)
Interface1
Interface2
RouterA
Configuring routing protocols on the primary link and backup link to ensure connectivity
at the network layer
Configure BFD sessions on the two routers on both ends of the link by referring to
Configuring a BFD Session.
NOTE
Only static BFD sessions with automatically negotiated discriminators and common static BFD
sessions are supported.
Run:
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IP
RouterC
RouterD
3G/ISDN/IP
1 Interface Backup Configuration
RouterB
Primary link
Backup link
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