一、实验拓扑
二、实验需求
- R2-7每台路由器均存在一个环回接口用于建立邻居，同时还存在一个环回来代表连接用户的接口。最终这些连接用户的接口网络需要可以和R1/8的环回通讯
- AS2网段地址172.16.0.0/16 减路由条目数量
三、实验思路
1、IP地址划分
AS2区域R2-7每台路由器各两个环回，六段骨干链路
划分方案：
骨干网段：172.16.0.0/19
R2-3:172.16.0.0/30 R3-4:172.16.0.4/30 R2-5:172.16.0.8/30
R4-7:172.16.0.12/30 R5-6:172.16.0.16/30 R6-7:172.16.0.20/30
R2loopback：172.16.32.0/19
建邻-172.16.32.0/24
用户-172.16.33.0/24
R3loopback：172.16.64.0/19
建邻-172.16.64.0/24
用户-172.16.65.0/24
R4loopback：172.16.96.0/19
建邻-172.16.96.0/24
用户-172.16.97.0/24
R5loopback：172.16.128.0/19
建邻-172.16.128.0/24
用户-172.16.129.0/24
R6loopback：172.16.160.0/19
建邻-172.16.160.0/24
用户-172.16.161.0/24
R7loopback：172.16.192.0/19
建邻-172.16.192.0/24
用户-172.16.193.0/24
四、实验步骤
1、配置IP地址
2、AS2内的R2-R7起ospf
[R2]ospf 1 router-id 2.2.2.2
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 172.16.0.0 0.0.255.255
[R3]ospf 1 router-id 3.3.3.3
[R3-ospf-1]area 0
[R3-ospf-1-area-0.0.0.0]network 172.16.0.0 0.0.255.255
[R4]ospf 1 router-id 4.4.4.4
[R4-ospf-1]area 0
[R4-ospf-1-area-0.0.0.0]network 172.16.0.0 0.0.255.255
[R5]ospf 1 router-id 5.5.5.5
[R5-ospf-1]area 0
[R5-ospf-1-area-0.0.0.0]network 172.16.0.0 0.0.255.255
[R6]ospf 1 router-id 6.6.6.6
[R6-ospf-1]area 0
[R6-ospf-1-area-0.0.0.0]network 172.16.0.0 0.0.255.255
[R7]ospf 1 router-id 7.7.7.7
[R7-ospf-1]area 0
[R7-ospf-1-area-0.0.0.0]network 172.16.0.0 0.0.255.255
3、建立bgp邻居关系
[R1]bgp 1
[R1-bgp]router-id 1.1.1.1
[R1-bgp]peer 12.1.1.2 as-number 2
R2，R3，R4在同一联邦内，小AS号为64512
[R2]bgp 64512
[R2-bgp]router-id 2.2.2.2
[R2-bgp]confederation id 2
[R2-bgp]confederation peer-as 64513
[R2-bgp]peer 12.1.1.1 as-number 1
[R2-bgp]peer 172.16.64.1 as-number 64512
[R2-bgp]peer 172.16.64.1 connect-interface LoopBack 0
[R2-bgp]peer 172.16.128.1 as-number 64513
[R2-bgp]peer 172.16.128.1 connect-interface LoopBack 0
[R2-bgp]peer 172.16.128.1 ebgp-max-hop 2
[R3]bgp 64512
[R3-bgp]router-id 3.3.3.3
[R3-bgp]confederation id 2
[R3-bgp]peer 172.16.32.1 as-number 64512
[R3-bgp]peer 172.16.32.1 connect-interface LoopBack 0
[R3-bgp]peer 172.16.96.1 as-number 64512
[R3-bgp]peer 172.16.96.1 connect-interface LoopBack 0
[R4]bgp 64512
[R4-bgp]router-id 4.4.4.4
[R4-bgp]confederation id 2
[R4-bgp]confederation peer-as 64513
[R4-bgp]peer 172.16.64.1 as-number 64512
[R4-bgp]peer 172.16.64.1 connect-interface LoopBack 0
[R4-bgp]peer 172.16.192.1 as-number 64513
[R4-bgp]peer 172.16.192.1 connect-interface LoopBack 0
[R4-bgp]peer 172.16.192.1 ebgp-max-hop 2
R5，R6，R7在同一联邦内，小AS号为64513
[R5]bgp 64513
[R5-bgp]router-id 5.5.5.5
[R5-bgp]confederation id 2
[R5-bgp]confederation peer-as 64512
[R5-bgp]peer 172.16.32.1 as-number 64512
[R5-bgp]peer 172.16.32.1 connect-interface l
[R5-bgp]peer 172.16.32.1 connect-interface LoopBack 0
[R5-bgp]peer 172.16.32.1 ebgp-max-hop 2
[R5-bgp]peer 172.16.160.1 as-number 64513
[R5-bgp]peer 172.16.160.1 connect-interface LoopBack 0
[R6]bgp 64513
[R6-bgp]confederation id 2
[R6-bgp]peer 172.16.128.1 as-number 64513
[R6-bgp]peer 172.16.128.1 connect-interface LoopBack 0
[R6-bgp]peer 172.16.192.1 as-number 64513
[R6-bgp]peer 172.16.192.1 connect-interface LoopBack 0
[R7]bgp 64513
[R7-bgp]confederation id 2
[R7-bgp]confederation peer-as 64512
[R7-bgp]peer 78.1.1.2 as-number 3
[R7-bgp]peer 172.16.160.1 as-number 64513
[R7-bgp]peer 172.16.160.1 connect-interface LoopBack 0
[R7-bgp]peer 172.16.96.1 as-number 64512
[R7-bgp]peer 172.16.96.1 connect-interface LoopBack 0
[R7-bgp]peer 172.16.96.1 ebgp-max-hop 2
[R8]bgp 3
[R8-bgp]router-id 8.8.8.8
[R8-bgp]peer 78.1.1.1 as-number 2
避免两两间均要建立ibgp邻居关系，有条件的打破ibgp水平分割
R3和R6充当路由反射器
[R3-bgp]peer 172.16.32.1 reflect-client
[R6-bgp]peer 172.16.192.1 reflect-client
R2和R7修改条目属性，修改本地邻居的下一跳
[R2-bgp]peer 172.16.64.1 next-hop-local
[R2-bgp]peer 172.16.128.1 next-hop-local
[R7-bgp]peer 172.16.96.1 next-hop-invariable
[R7-bgp]peer 172.16.160.1 next-hop-local
R1已经学习到了去R8的环回
宣告用户环回网段
[R2-bgp]network 172.16.33.0 24
[R3-bgp]network 172.16.65.0 24
[R4-bgp]network 172.16.97.0 24
[R5-bgp]network 172.16.129.0 24
[R6-bgp]network 172.16.161.0 24
[R7-bgp]network 172.16.193.0 24
测试用户环回可以和R1/8的环回通讯
