[网络转载] 2.1.2不连续网络与RIP

TOPO

基础配置如下
r1
interface Serial0
ip address 192.1.1.1 255.255.255.0
clockrate 64000
!
interface Serial1
ip address 148.1.1.1 255.255.255.0
clockrate 64000
!
router rip
network 148.1.0.0
network 192.1.1.0
!
r2
interface Serial1
ip address 148.1.1.2 255.255.255.0
!
router rip
network 148.1.0.0
!
r3
interface Serial0
ip address 192.1.1.2 255.255.255.0
!
router rip
network 192.1.1.0
!
首先r3接受r1更新，r1为网络边界，将进行汇总。。
然后
在R3上配置环回口148.1.2.1/24后r3仍然受到r1更新
02:59:13: RIP: received v1 update from 192.1.1.1 on Serial0
02:59:13:      148.1.0.0 in 1 hops
但是察看路由表时，
R       148.1.0.0/16 [120/1] via 192.1.1.1, 00:01:47, Serial0
这条路由过了30秒却没有更新
r3#sh 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, su - IS-IS summary, 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
C    192.1.1.0/24 is directly connected, Serial0
     148.1.0.0/16 is variably subnetted, 2 subnets, 2 masks
R       148.1.0.0/16 [120/1] via 192.1.1.1, 00:01:47, Serial0
C       148.1.2.0/24 is directly connected, Loopback0

180s后r3到r1的更新变为metric16 ，即过了invilid时间，到了hold-down时间，路由表中显示为passbily down
03:01:05: RIP: sending v1 update to 255.255.255.255 via Serial0 (192.1.1.2)
03:01:05: RIP: build update entries
03:01:05:       network 148.1.0.0 metric 16
r3仍然接受r1的更新，但是r3的环回口是直连，所以接收到相同的r1更新后，它丢弃
r3#
03:02:03: RIP: received v1 update from 192.1.1.1 on Serial0
03:02:03:      148.1.0.0 in 1 hops
再过60秒，删除       R  148.1.0.0/16 [120/1] via 192.1.1.1, Serial0

r3#
03:02:27: RIP: sending v1 update to 255.255.255.255 via Serial0 (192.1.1.2)
03:02:27: RIP: build update entries - suppressing null update
r3#sh 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, su - IS-IS summary, 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
C    192.1.1.0/24 is directly connected, Serial0
     148.1.0.0/24 is subnetted, 1 subnets
C       148.1.2.0 is directly connected, Loopback0
解决办法：
为r1到r3的两个接口增加第二个地址（此地址必须与不连续网络处于同一主网内），构成连续网络