BGP的同步规则(上)

一、拓扑图：

二、BGP同步规则：

1、配置完各路由器的IP地址和BGP协议。R2和R4再互指邻居。同时注意把R2上的router-id指高。以便R4能学到完整路由。

2、配置完之后，看一下各路由器中学习到的全网bgp路由：

R1#sh ip route bgp

     10.0.0.0/30 is subnetted, 4 subnets

B       10.1.255.4 [20/0] via 10.1.255.2, 01:30:06

B       10.1.255.12 [20/0] via 10.1.255.2, 01:30:06

B       10.1.255.8 [20/0] via 10.1.255.2, 01:30:36

     150.150.0.0/24 is subnetted, 1 subnets

B       150.150.1.0 [20/0] via 10.1.255.2, 01:30:06

R2#sh ip route bgp

B       10.1.255.12 [200/0] via 10.1.255.10, 01:31:06

B       10.1.255.8 [200/0] via 10.1.255.6, 01:31:13

     130.130.0.0/24 is subnetted, 1 subnets

B       130.130.1.0 [20/0] via 10.1.255.1, 01:31:13

B       150.150.1.0 [200/0] via 10.1.255.14, 01:31:01

R3#sh ip route bgp

B       10.1.255.0 [200/0] via 10.1.255.5, 01:31:21

B       10.1.255.12 [200/0] via 10.1.255.10, 04:52:27

B       130.130.1.0 [200/0] via 10.1.255.1, 01:31:15

B       150.150.1.0 [200/0] via 10.1.255.14, 04:52:22

R4#sh ip route bgp

B       10.1.255.4 [200/0] via 10.1.255.9, 01:32:32

B       10.1.255.0 [200/0] via 10.1.255.5, 01:31:39

B       130.130.1.0 [200/0] via 10.1.255.1, 01:31:34

B       150.150.1.0 [20/0] via 10.1.255.14, 04:52:46

R5#sh ip route bgp

B       10.1.255.4 [20/0] via 10.1.255.13, 04:53:03

B       10.1.255.0 [20/0] via 10.1.255.13, 01:31:56

B       10.1.255.8 [20/0] via 10.1.255.13, 04:53:03

B       130.130.1.0 [20/0] via 10.1.255.13, 01:31:25

3、从上面看到，各路由器全网的BGP路由都能学到，那么现在我们根据拓扑图在R2/R3/R4中运行ospf 协议。看一下对整个网络的影响：

R2(config)#router ospf 1

R2(config-router)#net 10.1.255.0 0.0.0.3 area 0

R2(config-router)#net 10.1.255.4 0.0.0.3 area 0

R3(config)#router ospf 1

R3(config-router)#net 10.1.255.4 0.0.0.3 area 0

R3(config-router)#net 10.1.255.8 0.0.0.3 area 0

R4(config)#router ospf 1

R4(config-router)#net 10.1.255.8 0.0.0.3 area 0

R4(config-router)#net 10.1.255.12 0.0.0.3 area 0

4、在配置完之后，发现对所有的路由器并没有影响，只是启用了ospf区域的路由以o来显示，但都能学习到全网的路由：

R1#sh ip route

………………

 10.0.0.0/30 is subnetted, 4 subnets

B       10.1.255.4 [20/0] via 10.1.255.2, 00:00:34

C       10.1.255.0 is directly connected, Serial1/1

B       10.1.255.12 [20/0] via 10.1.255.2, 00:00:03

B       10.1.255.8 [20/0] via 10.1.255.2, 00:00:03

C       130.130.1.0 is directly connected, Loopback0

B       150.150.1.0 [20/0] via 10.1.255.2, 00:00:03

R2#sh ip route

C       10.1.255.4 is directly connected, Serial1/1

C       10.1.255.0 is directly connected, Serial1/0

O       10.1.255.12 [110/192] via 10.1.255.6, 00:10:33, Serial1/1

O       10.1.255.8 [110/128] via 10.1.255.6, 00:10:33, Serial1/1

B       130.130.1.0 [20/0] via 10.1.255.1, 00:07:06

B       150.150.1.0 [200/0] via 10.1.255.14, 00:06:54

R3#sh ip route

C       10.1.255.4 is directly connected, Serial1/0

O       10.1.255.0 [110/128] via 10.1.255.5, 00:11:10, Serial1/0

O       10.1.255.12 [110/128] via 10.1.255.10, 00:11:10, Serial1/1

C       10.1.255.8 is directly connected, Serial1/1

B       130.130.1.0 [200/0] via 10.1.255.1, 00:07:42

B       150.150.1.0 [200/0] via 10.1.255.14, 00:07:31

R4#sh ip route

O       10.1.255.4 [110/128] via 10.1.255.9, 00:11:47, Serial1/0

O       10.1.255.0 [110/192] via 10.1.255.9, 00:11:47, Serial1/0

C       10.1.255.12 is directly connected, Serial1/1

C       10.1.255.8 is directly connected, Serial1/0

B       130.130.1.0 [200/0] via 10.1.255.1, 00:08:07

B       150.150.1.0 [20/0] via 10.1.255.14, 00:08:07

R5#sh ip route

B       10.1.255.4 [20/0] via 10.1.255.13, 00:08:31

B       10.1.255.0 [20/0] via 10.1.255.13, 00:08:31

C       10.1.255.12 is directly connected, Serial1/0

B       10.1.255.8 [20/0] via 10.1.255.13, 00:08:00

B       130.130.1.0 [20/0] via 10.1.255.13, 00:08:31

C       150.150.1.0 is directly connected, Loopback0

5、那么在R1/R2/R3都开启同步，看一下对EBGP有什么影响:

R2(config)#router bgp 64513

R2(config-router)#syn

R3(config)#router bgp 64513

R3(config-router)#syn

R4(config)#router bgp 64513

R4(config-router)#syn

6、发现R1和R2学不到150.150.1.0/24这条路由了：

B       10.1.255.4 [20/0] via 10.1.255.2, 00:08:49

B       10.1.255.12 [20/0] via 10.1.255.2, 00:08:49

B       10.1.255.8 [20/0] via 10.1.255.2, 00:08:49

O       10.1.255.12 [110/192] via 10.1.255.6, 00:49:28, Serial1/1

O       10.1.255.8 [110/128] via 10.1.255.6, 00:49:28, Serial1/1

B       130.130.1.0 [20/0] via 10.1.255.1, 00:09:00

             (一篇发不了，请接着看下篇)

本文转自wxs-163 51CTO博客，原文链接:http://blog.51cto.com/supercisco/268997