月影冥凌 2007-12-3 19:57
关于ＲＩＰ的计时器问题
视频和书上都说在ＲＩＰ中当出现possibly down时接收不同源的ＭＥＴＲＩＣ值较好的路由信息，但我在实验中他确不接收！！！！！！！！！！！！！！！！
也就是说在ＲＩＰ中当出现possibly down时将不接收任何更新信息
我作了实验验证！！！！！！！！！！！！！！拓扑图
[img=440,213]http://www.one-tom.com/bbs/uploads/20070730_220913_wang.JPG[/img] 先配好ＩＰ地址后在（Ｒ１是中间的）
首先将Ｒ２起ＲＩＰ，然后在输入
r1(config)#router rip
r1(config-router)#offset
r1(config-router)#offset-list 1 out 8 s2/0（表示出次口加８ＨＯＰＳ，有相关帖）
启动ＲＩＰ后并Ｐ通后，此时Ｒ１中路由信息为
[size=3][font=Times New Roman]
20.0.0.0/24 is subnetted, 1 subnets[/font][/size]
[font=Times New Roman][size=3]C
20.20.20.0 is directly connected, Serial2/0[/size][/font]
[size=3][font=Times New Roman]
10.0.0.0/24 is subnetted, 1 subnets[/font][/size]
[font=Times New Roman][size=3]C
10.10.10.0 is directly connected, Serial1/0[/size][/font]
[font=Times New Roman][size=3]R
30.0.0.0/8[color=#cc00cc] [120/9][/color] via 10.10.10.2, 00:00:01, Serial1/0（注意一下９跳）[/size][/font]
然后将Ｒ３的Ｓ１／０设为被动接口并起ＬＯＯＫＢＡＣＫ ０ ３０.３０.３０.３
然后将Ｒ２的接口Ｓ２／０设为被动接口 等三分钟后
在Ｒ１上deb ip rip
在R1上出现如下现象
[font=Times New Roman][size=3]Jul 30 04:49:15.835: RIP: sending v1 flash update to 255.255.255.255 via Serial2/0 (20.20.20.1)[/size][/font]
[font=Times New Roman][size=3]*Jul 30 04:49:15.835: RIP: build flash update entries[/size][/font]
[font=Times New Roman][size=3]*Jul 30 04:49:15.835:
network 30.0.0.0 metric 16[/size][/font]
[font=Times New Roman][size=3]*Jul 30 04:49:15.835: RIP: sending v1 flash update to 255.255.255.255 via Serial1/0 (10.10.10.1)[/size][/font]
[font=Times New Roman][size=3]*Jul 30 04:49:15.835: RIP: build flash update entries[/size][/font]
[size=3][font=Times New Roman]*[color=lime]Jul 30 04:49:15.835:
network 30.0.0.0 metric 16 （注意一下时间）[/color][/font][/size]
[font=Times New Roman][size=3]r1#sh ip rou[/size][/font]
[font=Times New Roman][size=3]Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP[/size][/font]
[size=3][font=Times New Roman]
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area [/font][/size]
[size=3][font=Times New Roman]
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2[/font][/size]
[size=3][font=Times New Roman]
E1 - OSPF external type 1, E2 - OSPF external type 2[/font][/size]
[size=3][font=Times New Roman]
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2[/font][/size]
[size=3][font=Times New Roman]
ia - IS-IS inter area, * - candidate default, U - per-user static route[/font][/size]
[size=3][font=Times New Roman]
o - ODR, P - periodic downloaded static router[/font][/size]
[font=Times New Roman][size=3] [/size][/font]
[font=Times New Roman][size=3]Gateway of last resort is not set[/size][/font]
[font=Times New Roman][size=3] [/size][/font]
[size=3][font=Times New Roman]
20.0.0.0/24 is subnetted, 1 subnets[/font][/size]
[font=Times New Roman][size=3]C
20.20.20.0 is directly connected, Serial2/0[/size][/font]
[size=3][font=Times New Roman]
10.0.0.0/24 is subnetted, 1 subnets[/font][/size]
[font=Times New Roman][size=3]C
10.10.10.0 is directly connected, Serial1/0[/size][/font]
[font=Times New Roman][size=3]R
30.0.0.0/8 is[color=#cc00ff] possibly down[/color], routing via 10.10.10.2, Serial1/0[/size]
[size=3]表名Ｒ１进入保持计时器阶段[/size]
[size=3]然后迅速将Ｒ３的Ｓ１／０口 打开（即将被动状态解除）[/size]
[size=3]在Ｒ１中看到如下信息[/size]
[size=3][/size]
[/font][font=宋体, MS Song][size=3] [/size][/font][color=lime][font=Times New Roman][size=3]*Jul 30 04:50:03.807: RIP: received v1 update from 20.20.20.2 on Serial2/0[/size][/font][/color]
[color=lime][size=3][font=Times New Roman]*Jul 30 04:50:03.807:
30.0.0.0 in 1 hops[/font][/size][/color]
[color=lime][size=3][font=Times New Roman]*Jul 30 04:50:09.355: RIP: sending v1 update to 255.255.255.255 via Serial1/0 (10.10.10.1)[/font][/size][/color]
[color=lime][size=3][font=Times New Roman]*Jul 30 04:50:09.355: RIP: build update entries[/font][/size][/color]
[color=lime][size=3][font=Times New Roman]*Jul 30 04:50:09.355:
network 20.0.0.0 metric 1[/font][/size][/color]
[color=lime][size=3][font=Times New Roman]*6Jul 30 04:50:09.355:
network 30.0.0.0 metric 16
[color=#000000]看到一分钟内[size=2]（和前边的出现possibly down的时间作差即可知道）[/size]收到 [color=#00ff00] 30.0.0.0 in 1 hops[/color]的更新信息，但是从另一个口仍转发[/color][color=#00ff00] network 30.0.0.0 metric 16 [/color]
[color=#000000]表明收到其他接口metric值较好的陆由信息他也不接收[/color]
[color=#000000]这和书上，视频上讲的有很大差别[/color]
[/font][/size][/color]
