Application Scenarios; Bfd For Ip Links - Huawei AR530 Series Configuration Manual

Huawei AR530&AR550 Series Industrial Switch Routers
Configuration Guide - Reliability
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5.3 Application Scenarios

This section describes the applicable scenario of BFD.

5.3.1 BFD for IP Links

You can create a single-hop or multi-hop BFD session on an IP link to rapidly detect faults:
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Application
Typical application 1
As shown in
BFD session is bound to the outbound interface.
Figure 5-4 Single-hop BFD for IP links
RouterA
Typical application 2
Issue 01 (2014-11-30)
RouterA and RouterB start BFD state machines respectively. The initial state of BFD state
machine is Down. RouterA and RouterB send BFD control packets with the State field as
Down. If BFD sessions are configured statically, the values of Remote Discriminator in
BFD packets are specified. If BFD sessions are configured dynamically, the value of
Remote Discriminator is set to 0.
After receiving the BFD packet with the State field as Down, RouterB switches the session
status to Init and sends a BFD packet with State field as Init.
After the local BFD session status of RouterB changes to Init, RouterB no longer processes
the received BFD packets with the State field as Down.
The BFD session status change on RouterA is similar to that on RouterB.
After receiving the BFD packet with the State field as Init, RouterB changes the local BFD
session status to Up.
The BFD session status change on RouterA is similar to that on RouterB.
Single-hop BFD detects IP connectivity of the forwarding link between two directly
connected systems.
Multi-hop BFD detects IP connectivity of paths between two indirectly connected systems.
These paths may span multiple hops or overlap.
Figure 5-4, a BFD session detects a single-hop path between two devices and the
BFD session
Interface 1
10.1.1.1/25
BFD session
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Interface 2
10.1.1.2/25
RouterB
5 BFD Configuration
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