3Com 10014299 manual Start BGP, Specify BGP transmission network, Configure peer

BGP Configuration Example 475

Figure 156 Networking diagram of configuring BGP path selection

				To network	AS200
		2.2.2.2		2.0.0.0
		S0		S0
		192.1.1.2/24		194.1.1.2/24
			Router B
	S0 192.1.1.1/24	EBGP		IBGP	S0
1.1.1.1						194.1.1.1/24
						4.4.4.4
To network		EBGP		IBGP
	Router A				S1	Router D
1.0.0.0
	S1 193.1.1.1/24				195.1.1.1/24
	AS100	S0 193.1.1.2/24	Router C	S1
				195.1.1.2/24
			3.3.3.3			To network
				To network		2.0.0.0
				2.0.0.0

1Configure Router A:

[RouterA] interface serial 0

[RouterA-Serial0]ip address 192.1.1.1 255.255.255.0 [RouterA] interface serial 1

[RouterA-Serial1]ip address 193.1.1.1 255.255.255.0

[RouterA-Serial1] quit

aStart BGP

[RouterA] bgp 100 [RouterA-bgp] undo synchronization

bSpecify BGP transmission network

[RouterA-bgp]network 1.0.0.0 mask 255.0.0.0

[RouterA-bgp]network 2.0.0.0 mask 255.0.0.0

cConfigure peer

[RouterA-bgp]peer 192.1.1.2 as-number 200

[RouterA-bgp]peer 193.1.1.2 as-number 200

dConfigure MED attribute of Router A

■Add access list to Router A and enable network 1.0.0.0.

[RouterA-bgp] acl 1

[RouterA-acl-1]rule permit source 1.0.0.0 0.255.255.255

■Define two routing diagram, namely set_med_50 and set_med_100. The first routing diagram is network 1.0.0.0. The MED attribute is 50, and the second MED attribute is 100.

[RouterA-acl-1]route-policy set_med_50 permit 1

[RouterA-route-policy] if-match ip address 1

[RouterA-route-policy] apply cost 50

[RouterA-route-policy] quit

[RouterA] route-policyset_med_100 permit 1

[RouterA-route-policy] if-match ip address 1

■[RouterA-route-policy] apply cost 100Apply the routing diagram set_med_50 to the exit routing update of Router C (193.1.1.2). Apply the routing diagram set_med_100 to exit routing update of Router B (192.1.1.2).

[RouterA] bgp 100

[RouterA-bgp]peer 193.1.1.2 route-policy set_med_50 export

[RouterA-bgp]peer 192.1.1.2 route-policy set_med_100 export