I. Overview of Dynamic Routing:
Dynamic routing is a concept opposed to static routing, the router refers to the own routing table can be established automatically in accordance with certain routing information exchange between routers, and can be automatically adjusted according to changes in a timely manner to links and nodes. When the link between the node or network fails, or the presence of other available routes, dynamic routing can choose the best available route itself and continues to forward packets.
Second, dynamic routing features:
1, without administrator manual maintenance, reducing administrator workload.
2, taking up network bandwidth.
3, routing protocol running on the router, the router makes routing entries can be automatically adjusted according to changes in the network topology.
4, the network scale, complex network topology.
Third, the dynamic routing principles:
1, the router itself thank the direct link information according to a certain routing algorithm to the collected routing information into the routing table processing for inspection at routers forward IP packets. 
2, timely exchange routing information between routers. Because when the network changes, the routers exchange routing information between each other will be informed of this change the other network, through the diffusion of information so that all network routers that can change. 
3, when the network changes, the routing information collected to date, recalculate the routing algorithm, which can obtain the latest routing table.
Four, RIP-- distance - vector routing protocol:
RIP is an interior gateway protocol is a dynamic routing protocol, routing information is used within an autonomous system. RIP protocol based on the distance vector algorithm, using the number of "hops" to measure the distance of the route to the destination address. This router agreement concerned only with the world around them, only to exchange information with their neighboring routers, the range is limited to 15 hops (15 degrees), the further away, it does not care anymore. RIP applied to the application layer of the OSI network model five, the routing information is updated once every 30 seconds, which port number UDP520.
Five, RIP configuration:
1, enable RIP:
Router (config) #router RIP
2, declares the Sovereign network number:
Router (config-Router) #network Number The Network-
3, the routing table:
Router # Show ip route
4, view the configuration of routing protocols:
Router # show ip protocols
Six experimental analysis:
1, the topology of the experiment
路由器R1：
f0/0接口：192.168.10.1/24
f0/1接口：192.168.20.1/30
路由器R2：
f0/0接口：192.168.20.2/30
f0/1接口：192.168.30.1/30
路由器R3：
f0/0接口：192.168.30.2/30
f0/1接口：192.168.40.1/30
客户机PC1：
IP地址：192.168.10.2/24
客户机PC2：
IP地址：192.168.40.2/24 2, double-click the icon to open the router R1 to enter the configuration.
conf t 进入全局模式
int f0/0 进入f0/0接口
ip add 192.168.10.1 255.255.255.0 添加IP及子网掩码
no shut 开启端口服务
ex 退出端口
int f0/1 进入f0/1接口
ip add 192.168.20.1 255.255.255.252 添加IP及子网掩码
no shut 开启端口服务
ex 退出端口3, the implementation of "do show ip route" command to view the routing table, this time recording 10 and 20 segment information in the routing table. 
4, double-click the icon to open the router R2 into the configuration.
conf t 进入全局模式
int f0/0 进入f0/0接口
ip add 192.168.20.2 255.255.255.0 添加IP及子网掩码
no shut 开启端口服务
ex 退出端口
int f0/1 进入f0/1接口
ip add 192.168.30.1 255.255.255.252 添加IP及子网掩码
no shut 开启端口服务
ex 退出端口
do show ip route 查看路由表5, double click on the icon to enter the configuration router R3.
conf t 进入全局模式
int f0/0 进入f0/0接口
ip add 192.168.30.2 255.255.255.0 添加IP及子网掩码
no shut 开启端口服务
ex 退出端口
int f0/1 进入f0/1接口
ip add 192.168.40.1 255.255.255.252 添加IP及子网掩码
no shut 开启端口服务
ex 退出端口
do show ip route 查看路由表
6, double-click the icon to enter the client PC1 configuration.
ip 192.168.10.2 192.168.10.1 设定IP及子网掩码
7, double-click the icon to enter the client PC2 configuration.
ip 192.168.40.2 192.168.40.1 设定IP及子网掩码
8, back to the router R1 continues configuration.
router rip 进入rip路由协议
network 192.168.10.0 宣告自身直连网段
network 192.168.20.0 宣告自身直连网段
version 2 启用路由协议2版
no auto-summary 关闭路由自动汇总
ex 退出9, back to the router R2 continue the configuration.
router rip 进入rip路由协议
network 192.168.20.0 宣告自身直连网段
network 192.168.30.0 宣告自身直连网段
version 2 启用路由协议2版
no auto-summary 关闭路由自动汇总
ex 退出10, returned to the router R3 continue the configuration.
router rip 进入rip路由协议
network 192.168.30.0 宣告自身直连网段
network 192.168.40.0 宣告自身直连网段
version 2 启用路由协议2版
no auto-summary 关闭路由自动汇总
ex 退出11, the implementation of "do show ip route" command in R1 30 and 40 can view the information network router R1 R2 automatically learned router forwarding routing table. 
12, the implementation of "do show ip route" command in router R2 R2 can view information and automatic learning 10 to 40 network routers R1 and R3 forwarding routing table. 
13, the implementation of "do show ip route" command in R3 can view information 10 20 network router R2 R2 automatically learned router forwards the routing table. 
14, use the ping command to test interoperability with the client in the client PC2 from PC1. 
15, use the ping command interoperability testing with the client in the client PC2 PC1 in.