理论知识：

实践1

配置R1  
[R1]rip  
[R1-rip-1]network 192.168.12.0  
[R1-rip-1]network 172.16.0.0  

配置R2  
[R2]rip   
[R2-rip-1]network 192.168.12.0  
[R2-rip-1]network 192.168.23.0  

配置R3  
[R3]rip  
[R3-rip-1]network 192.168.23.0  
[R3-rip-1]network 172.16.0.0  

>>> RIPv2 版本配置  
配置R1  
[R1]rip 1  
[R1-rip-1]version 2  
[R1-rip-1]no summary  

配置R2  
[R2]rip 1  
[R2-rip-1]version 2  
[R2-rip-1]undo summary  

配置R3  
[R3]rip 1  
[R3-rip-1]version 2  
[R3-rip-1]no summary