一、实验内容
二、拓扑图
三、实施
（1）底层—所有节点IP配置
R1: [R1-GigabitEthernet0/0/0]ip address 12.1.1.1 24 [R1-GigabitEthernet0/0/2]ip address 10.1.1.1 24 [R1]interface LoopBack 0 [R1-LoopBack0]ip address 1.1.1.1 32 ============================================= R2: [R2-GigabitEthernet0/0/1]ip address 12.1.1.2 24 [R2-GigabitEthernet0/0/2]ip address 20.1.1.1 24 [R2-GigabitEthernet0/0/0]ip address 23.1.1.1 24 [R2]interface LoopBack 0 [R2-LoopBack0]ip address 2.2.2.2 32 ============================================= R3: [R3-GigabitEthernet0/0/1]ip address 23.1.1.2 24 [R3-GigabitEthernet0/0/2]ip address 30.1.1.1 24 [R3-GigabitEthernet0/0/0]ip address 34.1.1.1 24 [R3]interface LoopBack 0 [R3-LoopBack0]ip address 3.3.3.3 32 ============================================= R4: [R4-GigabitEthernet0/0/1]ip address 34.1.1.2 24 [R4-GigabitEthernet0/0/2]ip address 40.1.1.1 24 [R4-GigabitEthernet0/0/0]ip address 45.1.1.1 24 [R4-GigabitEthernet4/0/0]ip address 54.1.1.1 24 [R4]interface LoopBack 0 [R4-LoopBack0]ip address 4.4.4.4 32 ============================================= R5: [R5-GigabitEthernet0/0/1]ip address 45.1.1.2 24 [R5-GigabitEthernet0/0/2]ip address 50.1.1.1 24 [R5-GigabitEthernet0/0/0]ip address 54.1.1.2 24 [R5]interface LoopBack 0 [R5-LoopBack0]ip address 5.5.5.5 32 ping 测试
（2） 路由—(IGP:AS内部互通，BGP：AS之间互通）
R2: [R2]ospf 1 router-id 2.2.2.2 [R2-ospf-1]area 0 [R2-ospf-1-area-0.0.0.0]network 23.1.1.1 0.0.0.0 [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 22.1.1.1 0.0.0.0 ================================================= R3: [R3]ospf 1 router-id 3.3.3.3 [R3-ospf-1]area 0 [R3-ospf-1-area-0.0.0.0]network 23.1.1.2 0.0.0.0 [R3-ospf-1-area-0.0.0.0]network 34.1.1.1 0.0.0.0 [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 30.1.1.1 0.0.0.0 ================================================= R4: [R4]ospf 1 router-id 4.4.4.4 [R4-ospf-1]area 0 [R4-ospf-1-area-0.0.0.0]network 4.4.4.4 0.0.0.0 [R4-ospf-1-area-0.0.0.0]network 34.1.1.2 0.0.0.0 [R4-ospf-1-area-0.0.0.0]network 40.1.1.1 0.0.0.0
查看R3上路由的邻接表、路由表，AS2内部已经互通
建BGP邻居（1-2，2-3，3-4，4-5，2-4）
R1: [R1]bgp 1 [R1-bgp]router-id 1.1.1.1 [R1-bgp]peer 12.1.1.2 as-number 2 ========================================== R2: [R2]bgp 2 [R2-bgp]router-id 2.2.2.2 [R2-bgp]peer 12.1.1.1 as-number 1 [R2-bgp]peer 3.3.3.3 as-number 2 [R2-bgp]peer 3.3.3.3 connect-interface LoopBack 0 [R2-bgp]peer 4.4.4.4 as-number 2 [R2-bgp]peer 4.4.4.4 connect-interface LoopBack 0 ========================================== R3: [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: [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 0 [R4-bgp]peer 2.2.2.2 as-number 2 [R4-bgp]peer 2.2.2.2 connect-interface LoopBack 0 [R4]ip route-static 5.5.5.0 24 45.1.1.2 [R4]ip route-static 5.5.5.0 24 54.1.1.2 [R4-bgp]peer 5.5.5.5 as-number 3 [R4-bgp]peer 5.5.5.5 connect-interface LoopBack 0 [R4-bgp]peer 5.5.5.5 ebgp-max-hop （改TTL值默认255） ========================================== R5: [R5]ip route-static 4.4.4.4 32 45.1.1.1 [R5]ip route-static 4.4.4.4 32 54.1.1.1 [R5]bgp 3 [R5-bgp]router-id 5.5.5.5 [R5-bgp]peer 4.4.4.4 as-number 2 [R5-bgp]peer 4.4.4.4 connect-interface LoopBack 0 [R5-bgp]peer 4.4.4.4 ebgp-max-hop 2
R2上tcp会话
查看R2R3R4上:BGP邻接表
（3）PC间互通（注意AS-BY-AS原则）
R1: [R1-bgp]network 10.1.1.0 24 ============================================= R2: [R2-bgp]peer 3.3.3.3 next-hop-local [R2-bgp]peer 4.4.4.4 next-hop-local [R2-bgp]network 20.1.1.0 24 ============================================= R3: [R3-bgp]network 30.1.1.0 24 ============================================= R4: [R4-bgp]peer 3.3.3.3 next-hop-local [R4-bgp]peer 2.2.2.2 next-hop-local [R4-bgp]network 40.1.1.0 24 ============================================= R5: [R5-bgp]network 50.1.1.0 24
（4）测试
