249
2.
Configure OSPF in AS 200 to make sure Switch A and Switch C can reach each other and
configure Switch A to redistribute BGP routes. (Details not shown.)
3.
Configure BGP on Switch A:
# Establish two IBGP connections between Switch A and Switch C, and configure Switch A to
advertise itself as the next hop.
<SwitchA> system-view
[SwitchA] bgp 100
[SwitchA-bgp] peer 3.0.2.2 as-number 200
[SwitchA-bgp] peer 2.0.2.2 as-number 200
[SwitchA-bgp] peer 3.0.2.2 next-hop-local
[SwitchA-bgp] peer 2.0.2.2 next-hop-local
# Configure Switch A to redistribute OSPF routes.
[SwitchA-bgp] import-route ospf
[SwitchA-bgp] quit
# When the two links between Switch A and Switch C are both up, Switch C adopts the link Switch
A<—>Switch B<—>Switch C to exchange packets with network 1.1.1.0/24. (Set a higher MED
value for route 1.1.1.0/24 sent to peer 2.0.2.2 on Switch A.)
{
Create ACL 2000 to permit 1.1.1.0/24 to pass.
[SwitchA] acl number 2000
[SwitchA-acl-basic-2000] rule permit source 1.1.1.0 24
[SwitchA-acl-basic-2000] quit
{
Create two route policies,
apply_med_50
and
apply_med_100
. Policy
apply_med_50
sets the
MED for route 1.1.1.0/24 to 50. Policy
apply_med_100
sets that to 100.
[SwitchA] route-policy apply_med_50 permit node 10
[SwitchA-route-policy] if-match acl 2000
[SwitchA-route-policy] apply cost 50
[SwitchA-route-policy] quit
[SwitchA] route-policy apply_med_100 permit node 10
[SwitchA-route-policy] if-match acl 2000
[SwitchA-route-policy] apply cost 100
[SwitchA-route-policy] quit
{
Apply routing policy
apply_med_50
to routes outgoing to peer 3.0.2.2, and apply routing
policy
apply_med_100
to routes outgoing to peer 2.0.2.2.
[SwitchA] bgp 100
[SwitchA-bgp] peer 3.0.2.2 route-policy apply_med_50 export
[SwitchA-bgp] peer 2.0.2.2 route-policy apply_med_100 export
# Configure BFD over the link to peer 3.0.2.2 so that when the link Switch A<—>Switch
B<—>Switch C fails, BFD can quickly detect the failure and notify it to BGP, and then the link
Switch A<—>Switch D<—>Switch C takes effect immediately.
[SwitchA-bgp] peer 3.0.2.2 bfd
# Establish an EBGP connection between Switch A and Switch E.
[SwitchA-bgp] peer 30.1.1.2 as-number 100
[SwitchA-bgp] quit
4.
Configure BGP on Switch C:
# Establish two IBGP connections between Switch A and Switch C.
<SwitchC> system-view