local preference属性

通告给ibgp邻居关于怎样离开本as

仅仅在同as内有效，不会超过ibgp边界

默认是100

自由的属性

router bgp 134

bgp default local-preference 200 (修改本地优先级）

ip prefix-list a permit 2.2.2.0/24

router-map lp permit 10

match ip add prefix-list a

set local-preference 200

router-map ip permit 20

router bgp 134

neighbor 3.3.3.3 router-map lp out

1.对network有效

2.对ebgp路由有效

3.对ibgp network无效

4.聚合路由有效，对本路由聚合的路由无效。

as path属性

r2:

ip prefix-list a permit 2.2.2.0/24

router-map as permit 10

match ip add prefix-list a

set as-path prepend(在之前) 7 8 9

router-map as permit 20

router bgp 2

neighbor 24.1.1.4 route-map as out

r4:

ip prefix-llist a permit 2.2.2.0/24

route-map as permit 10

match ip add prefxi-list as

set as-path prepend 7 8 9

router-map as permit 20

router bgp 134

neighbor 24.1.1.2 route-map as in

med 属性

通告给ebgp如何进入本as

r3:

router bgp 134

neighbor 1.1.1.1 weight 100

router bgp 134

default-meric 10000

r1:

access-list 10 permit 2.2.2.0

router-map med permit 10

match ip add 10

set metric 100

router-map med permit 20

router bgp 134

neighbor 12.1.1.2 route-map med in