0 个人信息
- 姓名：罗廷杨
- 学号：201821121013
- 班级：计算1811
- 理解RIP路由表的建立与更新
- 感受RIP坏消息传得慢
使用Packet Tracer，正确配置网络参数，使用命令查看和分析RIP路由信息。
- 建立网络拓扑结构
- 配置参数
- 分析RIP路由信息
网络拓扑图如下图所示：
PC0的配置
PC1的配置
Router1的配置
Router>enable
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface fa0/0
Router(config-if)#ip address 192.168.2.12 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#
%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
Router(config-if)#exit
Router(config)#interface fa0/1
Router(config-if)#ip address 192.168.3.12 255.255.255.0
Router(config-if)#no shutdown
Router(config-if)#
%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
Router(config-if)#exit
Router(config)#router rip
Router(config-router)#version 2
Router(config-router)#network 192.168.2.0
Router(config-router)#network 192.168.3.0
查看路由过程的信息
Router1
Router#show ip protocols
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 17 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: rip
Default version control: send version 2, receive 2
Interface Send Recv Triggered RIP Key-chain
FastEthernet0/0 2 2
FastEthernet0/1 2 2
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
192.168.2.0
192.168.3.0
Passive Interface(s):
Routing Information Sources:
Gateway Distance Last Update
192.168.2.13 120 00:00:00
Distance: (default is 120)
查年路由表show ip route
Router1
Router#show 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, 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
R 192.168.1.0/24 [120/1] via 192.168.2.13, 00:00:25, FastEthernet0/0
C 192.168.2.0/24 is directly connected, FastEthernet0/0
C 192.168.3.0/24 is directly connected, FastEthernet0/1
解释
查看RIP发送和接收报文debug ip rip
Router1
Router#debug ip rip
RIP protocol debugging is on
Router#RIP: received v2 update from 192.168.2.13 on FastEthernet0/0
192.168.1.0/24 via 0.0.0.0 in 1 hops
RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (192.168.2.12)
RIP: build update entries
192.168.3.0/24 via 0.0.0.0, metric 1, tag 0
RIP: sending v2 update to 224.0.0.9 via FastEthernet0/1 (192.168.3.12)
RIP: build update entries
192.168.1.0/24 via 0.0.0.0, metric 2, tag 0
192.168.2.0/24 via 0.0.0.0, metric 1, tag 0
RIP: received v2 update from 192.168.2.13 on FastEthernet0/0
192.168.1.0/24 via 0.0.0.0 in 1 hops
解释
通过命令shutdown关闭R0接口Fa0/0。在R0查看RIP路由更新信息debug ip rip，并简要（不需要每一步都分析）分析R0的路由表是如何再次收敛的。
注：命令undebug all停止调试输出。
Router#debug ip rip
RIP protocol debugging is on
Router#RIP: received v2 update from 192.168.2.12 on FastEthernet0/1
192.168.3.0/24 via 0.0.0.0 in 1 hops
RIP: received v2 update from 192.168.2.12 on FastEthernet0/1
192.168.3.0/24 via 0.0.0.0 in 1 hops
RIP: received v2 update from 192.168.2.12 on FastEthernet0/1
192.168.3.0/24 via 0.0.0.0 in 1 hops
RIP: received v2 update from 192.168.2.12 on FastEthernet0/1
192.168.3.0/24 via 0.0.0.0 in 1 hops
分析：当通过命令shutdown关闭R0接口Fa0/0时，路由器Router0到PC0的链路出了故障，Router0无法到达PC0，于是Router0把到PC0的距离改成16，但是很可能要经过30秒后Router0才把更新信息发给Router1，然而Router1已经先把自己的路由表发给了Router0，表明自己到PC0的距离为2，Router0收到Router1的更新报文后，误以为可以经过Router1到达PC0，于是把自己到PC0的距离改成了3，同理，Router1接着又更新自己的路由表，以为自己到PC0的距离是4，这样的更新一直继续下去，知道Router0和Router1到PC0的距离都增大到16时，Router0和Router1才知道原来PC0是不可达的，最终完成收敛。
（1）通过PING抓取ICMP报文，并分析。
SEQ NUMBER：序列号
（2）通过该实验如果有产生新的疑问，可以写出来，并尝试自己解决问题
什么是时间戳请求？
时间戳请求报文（类型值字段13）和时间戳应答报文（类型值字段14）用于测试两台主机之间数据报来回一次的传输时间。传输时，主机填充原始时间戳，接受方收到请求后填充接受时间戳后以类型值字段14的报文格式返回，发送方计算这个时间差。有些系统不响应这种报文。
来源：博客园
作者：浅笑安然lty
链接：https://www.cnblogs.com/lty1661489001/p/11758548.html