4.9 BGP等价负载均衡

1.R1配置OSPF

[R1]ospf 1 router-id 1.1.1.1
[R1-ospf-1]area 0
[R1-ospf-1-area-0.0.0.0]network 1.1.1.1 0.0.0.0
[R1-ospf-1-area-0.0.0.0]network 12.1.1.0 0.255.255.255

2.R2配置OSPF

[R2]ospf 1 router-id 2.2.2.2
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]network 12.1.1.0 0.255.255.255

3.R1配置IBGP、EBGP

[R1]bgp 12
[R1-bgp]router-id 1.1.1.1
[R1-bgp]peer 2.2.2.2 as-number 12
[R1-bgp]peer 2.2.2.2 connect-interface LoopBack 0
[R1-bgp]peer 2.2.2.2 next-hop-local
[R1-bgp]peer 13.1.1.3 as-number 300

4.R2配置IBGP、EBGP，2.2.2.2/32宣告进BGP

[R2]bgp 12
[R2-bgp]router-id 2.2.2.2 
[R2-bgp]peer 1.1.1.1 as-number 12
[R2-bgp]peer 1.1.1.1 connect-interface LoopBack 0
[R2-bgp]peer 1.1.1.1 next-hop-local
[R2-bgp]peer 23.1.1.3 as-number 300

5.R3配置EBGP

[R3]bgp 300
[R3-bgp]router-id 3.3.3.3
[R3-bgp]peer 13.1.1.1 as-number 12
[R3-bgp]peer 23.1.1.2 as-number 12

6.R2创建LoopBack 1，宣告进BGP

[R2]interface LoopBack 1
[R2-LoopBack1]ip address 1.1.2.1 32
[R2-LoopBack1]quit
[R2]bgp 12
[R2-bgp]network 1.1.2.1 32

7.R3查看BGP路由信息，由R1传入宣告路由

[R3]display bgp routing-table
 *>   1.1.2.1/32         13.1.1.1                              0      12i
 *                       23.1.1.2        0                     0      12i

8.R3配置负载均衡

[R3]bgp 300
[R3-bgp]maximum load-balancing ebgp 2

9.R3查看BGP路由信息，两个下一条，实现了负载均衡

[R3]display ip routing-table protocol bgp 
  1.1.2.1/32  EBGP    255  0           D   13.1.1.1        GigabitEthernet0/0/2
                    EBGP    255  0           D   23.1.1.2        GigabitEthernet0/0/1