我们再看看OSPF执行时的过程:(简单举例)
int s1 ip add int s2 ip add 172.2.0.1 255.255.255.0 (172.2.0.1/24) int s3 ip add 172.3.0.1 255.255.0.0 (172.3.0.1/16) int s4 ip add 172.4.0.1 255.255.0.0 (172.4.0.1/16) route ospf 10 network 10.1.1.1 0.0.0.0 area 0 network 172.2.0.0 0.0.255.255 area 0 |
当进入OSPF 10,OSPF首先执行network
172.16.0.0/24 is subnetted, 1 subnets O 172.16.0.0 [110/128] via 192.168.0.1, 00:00:00, Serialx O 10.1.1.0 [110/74] via 192.168.0.1, 00:00:05, Serialx |
我们再看当添加新的network后有什么结果?
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这里s3,s4都在Area 1(被标记为IA掩码16)。
总结:实际的网络范围在interface mask中已经说明了,这在所有的Routers的Link state database 被清楚标记,不会因OSPF的network配置而发生改变。而在OSPF的network配置中,inverse mask只是起到指明在本Router的OSPF process 中的网络范围的作用,如network 172.0.0.0 0.255.255.255指定范围从172.0.0.0 ~ 172.255.255.255,在次范围中的所有interface分配至Area 1,最后其他所有的地址被分配到Area 2。
如果在Stub Area 中,没有Loopback interface的情况下,甚至可以简单配制为
route ospf 10 network network 172.2.0.0 0.0.255.255 area 0 network 172.0.0.0 0.255.255.255 area 1 network 0.0.0.0 0.0.0.0 area 2 show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is not set O IA 172.3.0.0/16 [110/933] via 192.168.0.1, 00:00:05, Serialx O IA 172.4.0.0/16 [110/933] via 192.168.0.1, 00:00:02, Serialx 172.16.0.0/24 is subnetted, 1 subnets O 172.16.0.0 [110/128] via 192.168.0.1, 00:00:10, Serialx 10.0.0.0/24 is subnetted, 1 subnets O 10.1.1.0 [110/74] via 192.168.0.1, 00:00:05, Serialx router ospf 20 network 0.0.0.0 255.255.255.255 area x |
这样就不用单独指定网络范围了。
在其它类型中,推荐配置使用interface ip address,
network |