RIPV1：被動接口與單播更新
實驗目的
通過本實驗可以掌握：
（1）被動接口的含義、配置和應用場合
（2）單播更新的應用場合和配置
（3）RIPv1使用子網地址的條件
（4）RIPv1接收子網路由的原則
拓撲結構
R1：
R1(config)#int e0/0
R1(config-if)#ip add 172.16.4.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#int lo0
R1(config-if)#ip add 172.16.1.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#exit
R1(config)#router rip
R1(config-router)#v 1
R1(config-router)#network 172.16.0.0
R2:
R2(config)#int e0/0
R2(config-if)#ip add 172.16.4.2 255.255.255.0
R2(config-if)#no sh
R2(config-if)#int lo0
R2(config-if)#ip add 172.16.2.1 255.255.255.0
R2(config-if)#no sh
R2(config-if)#exit
R2(config)#router rip
R2(config-router)#v 1
R2(config-router)#network 172.16.0.0
R3:
R3(config)#int e0/0
R3(config-if)#ip add 172.16.4.3 255.255.255.0
R3(config-if)#no sh
R3(config-if)#int lo0
R3(config-if)#ip add 172.16.3.1 255.255.255.0
R3(config-if)#no sh
R3(config-if)#exit
R3(config)#router rip
R3(config-router)#v 1
R3(config-router)#net
R3(config-router)#network 172.16.0.0
實驗調試
分別查看R1.R2.R3的路有表：
R1#sh ip ro
Codes: C - connected, S - static, 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
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
172.16.0.0/24 is subnetted, 4 subnets
C 172.16.4.0 is directly connected, Ethernet0/0
C 172.16.1.0 is directly connected, Loopback0
R 172.16.2.0 [120/1] via 172.16.4.2, 00:00:07, Ethernet0/0
R 172.16.3.0 [120/1] via 172.16.4.3, 00:00:21, Ethernet0/0
R2#sh ip ro
Codes: C - connected, S - static, 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
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
172.16.0.0/24 is subnetted, 4 subnets
C 172.16.4.0 is directly connected, Ethernet0/0
R 172.16.1.0 [120/1] via 172.16.4.1, 00:00:18, Ethernet0/0
C 172.16.2.0 is directly connected, Loopback0
R 172.16.3.0 [120/1] via 172.16.4.3, 00:00:08, Ethernet0/0
從路由器R1和R2的路由表輸出可以看出，它們互相學習到了24位的路由條目，從而 可以說明，某些情況下RIPv1更新確實可以攜帶子網信息。
爲了達到實驗效果：
把R2的e0/0設爲被動接口。
R2：
R2(config)#router rip
R2(config-router)#v 1
R2(config-router)#passive-interface e0/0
R2#debug ip rip
RIP protocol debugging is on
R2#
*Mar 1 00:36:17.363: RIP: received v1 update from 172.16.4.3 on Ethernet0/0
*Mar 1 00:36:17.363: 172.16.3.0 in 1 hops
*Mar 1 00:36:18.255: %SYS-5-CONFIG_I: Configured from console by console
R2#
*Mar 1 00:36:18.687: RIP: received v1 update from 172.16.4.1 on Ethernet0/0
*Mar 1 00:36:18.687: 172.16.1.0 in 1 hops
R2#
*Mar 1 00:36:24.007: RIP: sending v1 update to 255.255.255.255 via Loopback0 (172.16.2.1)
*Mar 1 00:36:24.007: RIP: build update entries
*Mar 1 00:36:24.007: subnet 172.16.1.0 metric 2
*Mar 1 00:36:24.007: subnet 172.16.3.0 metric 2
*Mar 1 00:36:24.007: subnet 172.16.4.0 metric 1
R2#
R2#
*Mar 1 00:36:44.535: RIP: received v1 update from 172.16.4.3 on Ethernet0/0
*Mar 1 00:36:44.535: 172.16.3.0 in 1 hops
R2#
*Mar 1 00:36:45.939: RIP: received v1 update from 172.16.4.1 on Ethernet0/0
*Mar 1 00:36:45.943: 172.16.1.0 in 1 hops
從以上輸出可以看出，路由器R2確實不向被動接口e0/0發送路由更新，但被動接口e0/0能接受路由更新。
R2單播更新指向R1
R2：
R2(config)#router rip
R2(config-router)#v 1
R2(config-router)#neighbor 172.16.4.1
實驗調試：
分別查看R1和R3的路由表：
R1#sh ip ro
Codes: C - connected, S - static, 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
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
172.16.0.0/24 is subnetted, 4 subnets
C 172.16.4.0 is directly connected, Ethernet0/0
C 172.16.1.0 is directly connected, Loopback0
R 172.16.2.0 [120/1] via 172.16.4.2, 00:00:00, Ethernet0/0
R 172.16.3.0 [120/1] via 172.16.4.3, 00:00:12, Ethernet0/0
R3#sh ip ro
Codes: C - connected, S - static, 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
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
172.16.0.0/24 is subnetted, 3 subnets
C 172.16.4.0 is directly connected, Ethernet0/0
R 172.16.1.0 [120/1] via 172.16.4.1, 00:00:00, Ethernet0/0
C 172.16.3.0 is directly connected, Loopback0
分別查看R1和R3的路由表可以得知：R1學習到R2的環回口路由條目，而在R3卻沒有學習到R2的環回口路由條目。
總結：
RIPv1路由更新可以攜帶子網信息必須同時滿足兩個條件：
（1）整個網絡所有地址在同一個主類網絡；
（2）子網掩碼長度必須相同
（3）被動接口只能接收路由更新，不能以廣播或組播方式發送更新，但是可以以單播的方式 發送更新，配置單播更新的命令如下：
R1(config-router)#neighbor A.B.C.D