BGP选路原则（2）-local-preference
2、修改local preference改变选路
默认情况下R4的bgp表中：
R4#sh ip bgp
BGP table version is 2, local router ID is 44.44.44.44
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
* 1.1.1 .0/24 34.1.1.3 0 23 1 i
*> 24.1.1.2 0 23 1 i
修改local_preference改变选路
R4：
R4(config)#ip prefix-list 1 per 1.1.1 .0/24
R4(config)#route-map local-pref per 10
R4(config-route-map)#mat ip add prefix-list 1
R4(config-route-map)#set local-preference 200
R4(config)#router bgp 4
R4(config-router)#nei 34.1.1.3 route-map local-pref in
R4 BGP表：
R4#sh ip bgp
BGP table version is 3, local router ID is 44.44.44.44
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
* 1.1.1 .0/24 24.1.1.2 0 23 1 i
*> 34.1.1.3 200 0 23 1 i
如果在此基础上我们修改R2过来路由的weight，来比较weight和local-preference的优先级
R4：
R4(config)#ip prefix-list 2 per 1.1.1 .0/24
R4(config)#route-map weight per 20
R4(config-route-map)#mat ip add prefix-list 2
R4(config-route-map)#set weight 100
R4(config)#router bgp 4
R4(config-router)#nei 24.1.1.2 route-map weight in
BGP表：
R4#sh ip bgp
BGP table version is 2, local router ID is 44.44.44.44
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
* 1.1.1 .0/24 34.1.1.3 200 0 23 1 i
*> 24.1.1.2 100 23 1 i
Weight的优先级确实比local-preference高。