无色无味(杨波) 的Web Log(博客)

与V1兼容可以指定某些接口 
The interface-level "compatibility switches" recommended by RFC 1723 are implemented in Cisco IOS with the commands ip rip send version and ip rip receive version.

主要再研究一下ip splist-horizon

当前实验的示意图如上：
在这个网络中，如果R2的F0/0口上取消掉水平分隔（no ip split-horizon）后，通过Debug可以看到。

R2：
*Mar  1 00:29:31.411: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.5.1)
*Mar  1 00:29:31.411: RIP: build update entries
*Mar  1 00:29:31.411:   subnet 192.168.5.0 metric 1
*Mar  1 00:29:31.415:   subnet 192.168.5.16 metric 1
*Mar  1 00:29:31.415:   subnet 192.168.5.32 metric 2　　　这个路由条目明明是从通过F0/0口学到的。关闭掉水平分隔后，V1就会又从这个口发送出去！
*Mar  1 00:29:31.415:   subnet 192.168.5.64 metric 2
*Mar  1 00:29:31.415: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.5.1)
*Mar  1 00:29:31.419: RIP: build update entries
*Mar  1 00:29:31.419:   192.168.5.0/28 via 0.0.0.0, metric 1, tag 0
*Mar  1 00:29:31.419:   192.168.5.16/28 via 0.0.0.0, metric 1, tag 0
*Mar  1 00:29:31.423:   192.168.5.32/28 via 192.168.5.2, metric 2, tag 0　　（这个路由条目也是不应该出现在这儿的。）
*Mar  1 00:29:31.427:   192.168.5.64/28 via 0.0.0.0, metric 2, tag 0
R2#

打开IP split-horizon后。Debug如下：
R2#
*Mar  1 00:32:21.503: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.5.1)
*Mar  1 00:32:21.503: RIP: build update entries
*Mar  1 00:32:21.503:   subnet 192.168.5.16 metric 1
*Mar  1 00:32:21.507:   subnet 192.168.5.64 metric 2
*Mar  1 00:32:21.507: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.5.1)
*Mar  1 00:32:21.507: RIP: build update entries
*Mar  1 00:32:21.507:   192.168.5.16/28 via 0.0.0.0, metric 1, tag 0
*Mar  1 00:32:21.511:   192.168.5.64/28 via 0.0.0.0, metric 2, tag 0

我们可以在这儿看到Rip 进程就不会通过0/0口发送从F0、0口接收到的5.32这个网段的路由条目　。
*Mar  1 00:32:23.511: RIP: received v2 update from 192.168.5.18 on FastEthernet0/1
*Mar  1 00:32:23.511:      192.168.5.64/28 via 0.0.0.0 in 1 hops
*Mar  1 00:32:27.767: RIP: received v2 update from 192.168.5.2 on FastEthernet0/0
*Mar  1 00:32:27.767:      192.168.5.32/28 via 0.0.0.0 in 1 hops
*Mar  1 00:32:34.275: RIP: sending v2 update to 224.0.0.9 via FastEthernet0/1 (192.168.5.17)
*Mar  1 00:32:34.275: RIP: build update entries
*Mar  1 00:32:34.275:   192.168.5.0/28 via 0.0.0.0, metric 1, tag 0
*Mar  1 00:32:34.279:   192.168.5.32/28 via 0.0.0.0, metric 2, tag 0