OSPF-3:OSPF 对外部路由的选路规则完全验证版 [实验目的] 验证OSPF 中对外部路由路由的选择规则 OSPF 在选择外部路由的时候，遵循的原则是： [1]O E1 优于O E2 [2]在同样的情况下，Cost 越小越优先 [3]在 cost 相同的情况下，选择到达ASBR 最优的路径 下面来通过实验来验证该规则: [案例1]当外部路由都是O E1 的情况 基本配置：(注意ASBR 的配置) R1: interface Loopback0 ip address 1.1.1.1 255.255.255.0 ip ospf netw ork point-to-point ! interface Serial1/0 ip address 12.1.1.1 255.255.255.0 ! interface Serial2/0 ip address 13.1.1.1 255.255.255.0 ! router ospf 1 redistribute rip subnets metric-type 1 network 12.1.1.0 0.0.0.255 area 0 ! router rip version 2 network 13.0.0.0 distance 109(因为RIP 的 AD 大于OSPF,所以重发布到OSPF 中，会发生路由抖动,故将其改小，详解看等级三实验手册1.3) no auto-summary ! R2: interface Loopback0 ip address 2.2.2.2 255.255.255.0 ip ospf network point-to-point ! interface Serial1/0 ip address 24.1.1.2 255.255.255.0 ! interface Serial2/0 ip address 12.1.1.2 255.255.255.0 ! router ospf 1 network 12.1.1.0 0.0.0.255 area 0 network 24.1.1.0 0.0.0.255 area 0 ! R3: interface Loopback0 ip address 3.3.3.3 255.255.255.0 ip ospf network point-to-point ! interface Serial1/0 ip address 13.1.1.3 255.255.255.0 ! interface Serial2/0 ip address 35.1.1.3 255.255.255.0 ! router rip version 2 network 3.0.0.0 network 13.0.0.0 network 35.0.0.0 no auto-summary ! R 4: interface Loopback0 ip address 4.4.4.4 255.255.255.0 ip ospf network point-to-point ! interface Serial1/0 ip address 45.1.1.4 255.255.255.0 ! interface Serial2/0 ip address 24.1.1.4 255.255.255.0 ! router ospf 1 network 24.1.1.0 0.0.0.255 area 0 network 45.1.1.0 0.0.0.255 area 1 ! R5: interface Loopback0 ip address 5.5.5.5 255.255.255.0 ip ospf network point-to-point ! interface Serial1/0 ip address 35.1.1.5 255.255....
