R1的配置
bgp 100
peer 2.2.2.2 as-number 200
peer 2.2.2.2 ebgp-max-hop 255
peer 2.2.2.2 connect-interface LoopBack0
peer 3.3.3.3 as-number 200
peer 3.3.3.3 ebgp-max-hop 255
peer 3.3.3.3 connect-interface LoopBack0
group as200 internal
ipv4-family unicast
undo synchronization
network 100.1.1.0 255.255.255.0
network 100.1.2.0 255.255.255.0
peer 2.2.2.2 enable
peer 2.2.2.2 route-policy 10 import
peer 3.3.3.3 enable
peer as200 enable
route-policy 10 permit node 10
if-match acl 2000
apply as-path 200 200 additive
route-policy 10 permit node 20
R1路由表
R1路由表60网络详细信息
原文：http://blog.51cto.com/9616635/2063766