3Com S7902E, Configuration Manual

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*>i 1.0.0.0 193.1.1.1 50 100 0 100i
* i 192.1.1.1 100 100 0 100i
You can find route 1.0.0.0/8 is the optimal.
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Configure different local preferences on Switch B and C for route 1.0.0.0/8, making Switch D give
priority to the route from Switch C.
# Define an ACL numbered 2000 on Router C, permitting route 1.0.0.0/8.
[SwitchC] acl number 2000
[SwitchC-acl-basic-2000] rule permit source 1.0.0.0 0.255.255.255
[SwitchC-acl-basic-2000] quit
# Configure a routing policy named localpref on Switch C, setting the local preference of route 1.0.0.0/8
to 200 (the default is 100).
[SwitchC] route-policy localpref permit node 10
[SwitchC-route-policy] if-match acl 2000
[SwitchC-route-policy] apply local-preference 200
[SwitchC-route-policy] quit
# Apply routing policy localpref to routes from peer 193.1.1.1.
[SwitchC] bgp 200
[SwitchC-bgp] peer 193.1.1.1 route-policy localpref import
[SwitchC-bgp] quit
# Display the routing table on Switch D.
[SwitchD] display bgp routing-table
Total Number of Routes: 2
BGP Local router ID is 194.1.1.1
Status codes: * - valid, > - best, d - damped,
h - history, i - internal, s - suppressed, S - Stale
Origin : i - IGP, e - EGP, ? - incomplete
Network NextHop MED LocPrf PrefVal Path/Ogn
*>i 1.0.0.0 193.1.1.1 0 200 0 100i
* i 192.1.1.1 0 100 0 100i
You can find route 1.0.0.0/8 from Switch D to Switch C is the optimal.
Configuring BFD for BGP
Network requirements
As shown in Figure 1-27 ,
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Switch A and Switch B are interconnected through a Layer 2 switch. BFD is enabled on the
connected interfaces. BGP is enabled on the switches that are reachable to each other at the
network layer.
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When the link between Switch A and Switch B fails, BFD can quickly detect the failure and notify
BGP of the failure.