拓扑:
MED是指在本地配置影响EBGP对等体进站
(默认值是 0 ,越小越优,)
现在要求在R1 R2上做流量分行,即R3 R4到达网络100.100.100.0/24 都是从R1
而到达200.200.200.0/24都是从R2
基本配置之前配置过了,与BGP的LP试验是一样的
在没做MED配置前先查看R3 R4的bgp路由表
R3#sh ip bgp
BGP table version is 3, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i100.100.100.0/24 1.1.1.1 0 100 0 100 i
*> 2.2.2.2 0 100 i
* i200.200.200.0 1.1.1.1 0 100 0 100 i
*> 2.2.2.2 0 0 100 i
R4#sh ip bgp
BGP table version is 4, local router ID is 4.4.4.4
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i100.100.100.0/24 2.2.2.2 0 100 0 100 i
*> 1.1.1.1 0 0 100 i
*> 200.200.200.0 1.1.1.1 0 100 i
* i 2.2.2.2 0 100 0 100 i
可以看到R3到达100.100.100.0/24以及200.200.200.0/24的下一跳都是2.2.2.2
可以看到R4到达100.100.100.0/24以及200.200.200.0/24的下一跳都是1.1.1.1
这是因为EBGP优与IBGP
现在要在R1 R2上做流量分行,R3 R4到达网络100.100.100.0/24 都是从R1即下一跳是(1.1.1.1)
而到达200.200.200.0/24都是从R2即下一跳是(2.2.2.2)
R1配置:
R1(config)#access-list 1 per 200.200.200.0 0.0.0.255 (在R1上标示出要施加策略的网络)
R1(config)#route-map ccxx per 10
R1(config-route-map)#ma ip add 1
R1(config-route-map)#set metric 1
R1(config-route-map)#exi
R1(config)#route-map ccxx per 20 (书写空route-map,相当与permit any)
R1(config-route-map)#exi
R1(config)#router bgp 100
R1(config-router)#nei 4.4.4.4 route-map ccxx out (在BGP进程下套用策略)
R2配置
R2(config)#access-list 1 per 100.100.100.0 0.0.0.255
R2(config)#route-map ccxx per 10
R2(config-route-map)#match ip address 1
R2(config-route-map)#set metric 1
R2(config-route-map)#exi
R2(config)#route-map ccxx per 20
R2(config-route-map)#exi
R2(config)#router bgp 100
R2(config-router)#nei 3.3.3.3 route-map ccxx out
做好后再查看R3 R4的BGP路由表:
R3#sh ip bgp
BGP table version is 4, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i100.100.100.0/24 1.1.1.1 0 100 0 100 i
* 2.2.2.2 1 0 100 i
*> 200.200.200.0 2.2.2.2 0 0 100 i
R4#sh ip bgp
BGP table version is 5, local router ID is 4.4.4.4
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 100.100.100.0/24 1.1.1.1 0 0 100 i
* 200.200.200.0 1.1.1.1 1 0 100 i
*>i 2.2.2.2 0 100 0 100 i
与想要的结果完全一致!!1 (*^__^*) 嘻嘻……