rip协议的V1和V2的更新机制
实验拓扑：
实验步骤：
R1:
router rip
network 1.0.0.0
network 192.168.12.0
R2:
router rip
network 2.0.0.0
network 192.168.12.0
如果没有在路由配置模式下，敲命令Version 2的话，运行的是RIP version 1版本。
在R2上debug ip rip
R2(config)#router rip
R2(config-router)# network 2.0.0.0
R2(config-router)# network 192.168.12.0
R2(config-router)#
*Jun 4 09:40:46.279: RIP: add Loopback2 to RIP idb list
*Jun 4 09:40:46.279: RIP: sending request on Loopback2 to 255.255.255.255 //发送广播更新
*Jun 4 09:40:47.099: RIP: add Serial1/0 to RIP idb list
*Jun 4 09:40:47.099: RIP: sending request on Serial1/0 to 255.255.255.255
*Jun 4 09:40:47.143: RIP: received v1 update from 192.168.12.1 on Serial1/0
*Jun 4 09:40:47.147: RIP: Update contains 1 routes
*Jun 4 09:40:48.279: RIP: sending v1 flash update to 255.255.255.255 via Loopback2 (2.2.2.2)
*Jun 4 09:40:48.279: RIP: Update contains 2 routes
*Jun 4 09:40:48.279: RIP: Update queued
*Jun 4 09:40:48.279: RIP: sending v1 flash update to 255.255.255.255 via Serial1/0 (192.168.12.2)
*Jun 4 09:40:48.279: RIP: Update contains 1 routes
*Jun 4 09:40:48.279: RIP: Update queued
*Jun 4 09:40:48.279: RIP: Update sent via Loopback2
*Jun 4 09:40:48.279: RIP: Update sent via Serial1/0
R1:
*Jun 4 09:44:47.695: RIP: sending v1 update to 255.255.255.255 via Serial1/1 (192.168.12.1)
*Jun 4 09:44:47.699: RIP: Update contains 1 routes//只向邻居通告直接的接口地址
*Jun 4 09:44:47.699: RIP: Update queued
*Jun 4 09:44:47.699: RIP: Update sent via Serial1/1
R1#
*Jun 4 09:44:52.631: RIP: sending v1 update to 255.255.255.255 via Loopback0 (1.1.1.1)
*Jun 4 09:44:52.635: RIP: Update contains 2 routes
*Jun 4 09:44:52.635: RIP: Update queued
*Jun 4 09:44:52.635: RIP: Update sent via Loopback0//只向邻居通告直接的接口地址
R1#
*Jun 4 09:45:13.543: RIP: sending v1 update to 255.255.255.255 via Serial1/1 (192.168.12.1)
*Jun 4 09:45:13.547: RIP: Update contains 1 routes
*Jun 4 09:45:13.547: RIP: Update queued
*Jun 4 09:45:13.547: RIP: Update sent via Serial1/1
*Jun 4 09:45:13.595: RIP: received v1 update from 192.168.12.2 on Serial1/1
*Jun 4 09:45:13.599: RIP: Update contains 1 routes
R1#
*Jun 4 09:45:20.487: RIP: sending v1 update to 255.255.255.255 via Loopback0 (1.1.1.1)
*Jun 4 09:45:20.491: RIP: Update contains 2 routes
*Jun 4 09:45:20.491: RIP: Update queued
*Jun 4 09:45:20.491: RIP: Update sent via Loopback0
红色字体表明rip V1会每30s左右（debug信息中显示27s）发送一次更新
如果此时在R2上添加一个loopback 0 地址为22.22.22.22/24的话，从debug ip rip events中看出：
*Jun 4 09:50:12.159: RIP: sending v1 flash update to 255.255.255.255 via Loopback0 (22.22.22.22) - suppressing null update
*Jun 4 09:50:12.163: RIP: Update sent via Loopback2
此时R1上已经有22.0.0.0的路由了
R1#show ip route rip
R 2.0.0.0/8 [120/1] via 192.168.12.2, 00:00:13, Serial1/1
R 22.0.0.0/8 [120/1] via 192.168.12.2, 00:00:13, Serial1/1
如果将R2的loopback 0端口给关闭了，此时在180s后将此条路由跳数设置为16，如果过了240s后，还没有收到此条更新的话，这条路由将彻底在路由表中删除！
此时将R2的RIP改为V2后，会发生什么情况呢？
*Jun 4 09:57:22.151: RIP: ignored v2 packet from 2.2.2.2 (sourced from one of our addresses)
*Jun 4 09:57:24.467: RIP: ignored v1 packet from 192.168.12.1 (illegal version) //提示版本不兼容
*Jun 4 09:57:47.503: RIP: sending v2 update to 224.0.0.9 via Serial1/0 (192.168.12.2)
*Jun 4 09:57:47.507: RIP: Update contains 1 routes
*Jun 4 09:57:47.507: RIP: Update queued
*Jun 4 09:57:47.507: RIP: Update sent via Serial1/0
*Jun 4 09:57:50.219: RIP: sending v2 update to 224.0.0.9 via Loopback2 (2.2.2.2)
*Jun 4 09:57:50.219: RIP: Update contains 2 routes
*Jun 4 09:57:50.223: RIP: Update queued
*Jun 4 09:57:50.223: RIP: Update sent via Loopback2
*Jun 4 09:57:50.227: RIP: ignored v2 packet from 2.2.2.2 (sourced from one of our addresses)
*Jun 4 09:57:50.563: RIP: ignored v1 packet from 192.168.12.1 (illegal version)
此时要么改R1的版本，要么在R2的接口模式下修改：
interface Serial1/0
ip address 192.168.12.2 255.255.255.0
ip rip send version 1 //发送是版本1
ip rip receive version 1 //接收是版本2
debug信息显示如下：
R2#
*Jun 4 09:59:41.907: RIP: received v1 update from 192.168.12.1 on Serial1/0
*Jun 4 09:59:41.911: RIP: Update contains 1 routes
R2#
*Jun 4 09:59:43.639: RIP: sending v1 update to 255.255.255.255 via Serial1/0 (192.168.12.2)
*Jun 4 09:59:43.639: RIP: Update contains 1 routes
*Jun 4 09:59:43.639: RIP: Update queued
*Jun 4 09:59:43.639: RIP: Update sent via Serial1/0
*Jun 4 09:59:43.663: RIP: sending v2 update to 224.0.0.9 via Loopback2 (2.2.2.2)
*Jun 4 09:59:43.663: RIP: Update contains 2 routes
*Jun 4 09:59:43.667: RIP: Update queued
*Jun 4 09:59:43.667: RIP: Update sent via Loopback2
*Jun 4 09:59:43.671: RIP: ignored v2 packet from 2.2.2.2 (sourced from one of our addresses)
R2#show ip route rip
R 1.0.0.0/8 [120/1] via 192.168.12.1, 00:00:02, Serial1/0
修改R1为版本1后在debug上看到的信息：
R1(config-router)#
*Jun 4 10:03:07.779: RIP-TIMER: sending timer on Loopback0 expired
*Jun 4 10:03:07.779: RIP: sending v2 update to 224.0.0.9 via Loopback0 (1.1.1.1)//组播发送更新
*Jun 4 10:03:07.783: RIP: Update contains 3 routes
*Jun 4 10:03:07.783: RIP: Update queued
*Jun 4 10:03:07.787: RIP: Update sent via Loopback0
*Jun 4 10:03:07.787: RIP: ignored v2 packet from 1.1.1.1 (sourced from one of our addresses)
R1(config-router)#
*Jun 4 10:03:14.519: RIP-TIMER: age timer expired
R1(config-router)#
*Jun 4 10:03:15.691: RIP: received v2 update from 192.168.12.2 on Serial1/1
*Jun 4 10:03:15.695: RIP-DB: network_update with 2.0.0.0/8 succeeds//注意与下面的红色字体的区别。
*Jun 4 10:03:15.695: RIP-DB: adding 2.0.0.0/8 (metric 1) via 192.168.12.2 on Serial1/1 to RIP database
*Jun 4 10:03:15.699: RIP-DB: network_update with 22.0.0.0/8 succeeds
*Jun 4 10:03:15.699: RIP-DB: adding 22.0.0.0/8 (metric 1) via 192.168.12.2 on Serial1/1 to RIP database
*Jun 4 10:03:15.699: RIP: Update contains 2 routes
R1(config-router)#
*Jun 4 10:03:17.191: RIP-TIMER: sending timer on Serial1/1 expired
*Jun 4 10:03:17.191: RIP: sending v2 update to 224.0.0.9 via Serial1/1 (192.168.12.1)
*Jun 4 10:03:17.195: RIP: Update contains 1 routes
*Jun 4 10:03:17.195: RIP: Update queued
*Jun 4 10:03:17.199: RIP: Update sent via Serial1/1
在R1,R2上打了no auto-summary后 在R1上看到的debug ip rip database信息：
R1(config-router)#
*Jun 4 10:04:42.087: RIP: received v2 update from 192.168.12.2 on Serial1/1
*Jun 4 10:04:42.091: RIP-DB: network_update with 2.2.2.0/24 succeeds
*Jun 4 10:04:42.091: RIP-DB: adding 2.2.2.0/24 (metric 1) via 192.168.12.2 on Serial1/1 to RIP database
*Jun 4 10:04:42.095: RIP-DB: add 2.2.2.0/24 (metric 1) via 192.168.12.2 on Serial1/1
*Jun 4 10:04:42.095: RIP-DB: Adding new rndb entry 2.2.2.0/24
*Jun 4 10:04:42.099: RIP-DB: network_update with 22.22.22.0/24 succeeds
*Jun 4 10:04:42.099: RIP-DB: adding 22.22.22.0/24 (metric 1) via 192.168.12.2 on Serial1/1 to RIP database
*Jun 4 10:04:42.103: RIP-DB: add 22.22.22.0/24 (metric 1) via 192.168.12.2 on Serial1/1
