一、实验需求

按照规划建立BGP对等体关系，R1和R5各发布一条路由，保证两个网段可以互相通信

二、配置思路

划分网段

配置IP

AS 2运行OSPF协议，使得R2,R3,R4之间可以互相通信

建立对等体

发布路由

测试通信

三、配置命令

【1】配置IP地址

[r1]interface g0/0/0
[r1-GigabitEthernet0/0/0]ip address 12.0.0.1 24

[r1]interface loopback 0
[r1-LoopBack0]ip address 1.1.1.1 24

[r2]interface g0/0/0
[r2-GigabitEthernet0/0/0]ip address 12.0.0.2 24

[r2]interface loopback 0
[r2-LoopBack0]ip address 2.2.2.2 24

[r2]interface g0/0/1
[r2-GigabitEthernet0/0/1]ip address 23.0.0.1 24

[r3]interface g0/0/1
[r3-GigabitEthernet0/0/1]ip address 34.0.0.1 24

[r3]interface loopback 0
[r3-LoopBack0]ip address 3.3.3.3 24

[r3]interface g0/0/0
[r3-GigabitEthernet0/0/0]ip address 23.0.0.2 24

[r4]interface g0/00/0
[r4-GigabitEthernet0/0/0]ip address 34.0.0.2 24

[r4]interface loopback 0
[r4-LoopBack0]ip address 4.4.4.4 24

[r4]interface g0/0/1
[r4-GigabitEthernet0/0/1]ip address 45.0.0.1 24

[r5]interface g0/0/0
[r5-GigabitEthernet0/0/0]ip address 45.0.0.2 24

[r5]interface loopback 0
[r5-LoopBack0]ip address 5.5.5.5 24

[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 23.0.0.0 0.0.0.255

 【2】AS 2中运行OSPF协议，使R2,R3,R5之间路由可达

[r3-ospf-1]area 0
[r3-ospf-1-area-0.0.0.0]network 23.0.0.0 0.0.0.255

[r3-ospf-1-area-0.0.0.0]network 3.3.3.3 0.0.0.0
[r3-ospf-1-area-0.0.0.0]network 34.0.0.0 0.0.0.255

[r4]ospf 1 router-id 4.4.4.4
[r4-ospf-1]area 0
[r4-ospf-1-area-0.0.0.0]network 34.0.0.0 0.0.0.255

[r4-ospf-1-area-0.0.0.0]network 4.4.4.4 0.0.0.0

 【3】建立BGP对等体

R1 peer R2

[r1]bgp 1
[r1-bgp]router-id 1.1.1.1
[r1-bgp]peer 12.0.0.2 as-number 2

R2 peer R1 以及 R2 peer R3 

[r2]bgp 2
[r2-bgp]router-id 2.2.2.2
[r2-bgp]peer 12.0.0.1 as-number 1

[r2-bgp]peer 3.3.3.3 as-number 2
[r2-bgp]peer 3.3.3.3 connect-interface loopback 0      给3.3.3发消息使用环回接口发送

R3 peer R2 以及 R3 peer R4

[r3]bgp 2
[r3-bgp]router-id 3.3.3.3
[r3-bgp]peer 2.2.2.2 as-number 2

[r3-bgp]peer 2.2.2.2 connect-interface loopback 0

[r3-bgp]peer 4.4.4.4 as-number 2
[r3-bgp]peer 4.4.4.4 connect-interface loopback 0

R4 peer R3 以及 R4 peer R5

[r4]bgp 2
[r4-bgp]router-id 4.4.4.4[r4-bgp]peer 3.3.3.3 as-number 2
[r4-bgp]peer 3.3.3.3 connect-interface loopback
[r4-bgp]peer 45.0.0.2 as-number 3

R5 peer R4 

[r5]bgp 3
[r5-bgp]router-id 5.5.5.5
[r5-bgp]peer 45.0.0.1 as-number 2

【4】发布路由

[r1-bgp]network 1.1.1.0 24

[r5-bgp]network 5.5.5.0 24

【R5】修改下一跳属性

[r4-bgp]peer 3.3.3.3 next-hop-local

[r4-bgp]peer 2.2.2.2 next-hop-local

[r2-bgp]peer 3.3.3.3 next-hop-local

[r2-bgp]peer 4.4.4.4 next-hop-local

四、测试结果