OSPF选路原则.docVIP

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 Loopback0ip address 1.1.1.1 255.255.255.0ip ospf network point-to-point!interface Serial1/0ip address 12.1.1.1 255.255.255.0!interface Serial2/0ip address 13.1.1.1 255.255.255.0!router ospf 1redistribute rip subnets metric-type 1network 12.1.1.0 0.0.0.255 area 0!router ripversion 2network 13.0.0.0distance 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 Loopback0ip address 2.2.2.2 255.255.255.0ip ospf network point-to-point!interface Serial1/0ip address 24.1.1.2 255.255.255.0!interface Serial2/0ip address 12.1.1.2 255.255.255.0!router ospf 1network 12.1.1.0 0.0.0.255 area 0network 24.1.1.0 0.0.0.255 area 0!R3:interface Loopback0ip address 3.3.3.3 255.255.255.0ip ospf network point-to-point!interface Serial1/0ip address 13.1.1.3 255.255.255.0!interface Serial2/0ip address 35.1.1.3 255.255.255.0!router ripversion 2network 3.0.0.0network 13.0.0.0network 35.0.0.0no auto-summary!R4:interface Loopback0ip address 4.4.4.4 255.255.255.0ip ospf network point-to-point!interface Serial1/0ip address 45.1.1.4 255.255.255.0!interface Serial2/0ip address 24.1.1.4 255.255.255.0!router ospf 1network 24.1.1.0 0.0.0.255 area 0network 45.1.1.0 0.0.0.255 area 1!R5:interface Loopback0ip address 5.5.5.5 255.255.255.0ip ospf network point-to-point!interface Serial1/0ip address 35.1.1.5 255.255.255.0!interface Serial2/0ip address 45.1.1.5 255.255.255.0!router ospf 1redistribute rip subnets metric-type 1network 45.1.1.0 0.0.0.255 area 1!router ripversion 2network 35.0.0.0distance 109no auto-summary!监视和测试配置:查看R2的路由表:R2#sh ip rou 35.0.0.0/24 is subnetted, 1 subnetsO E135.1.1.0 [110/84] via 12.1.1.1, 00:00:25,