2.2 RIPV2配置详解

5.路由汇总

同一个网段内的不同子网路由向外通过时汇总成一条路由，用于减小网络设备的路由表规模，达到减小设备资源消耗。

手工路由汇总方式能解决自动汇总路由的掩码不够精确的问题，可以自定义目的网络地址及网络掩码。

[R1]rip 1    
[R1-rip-1]version 2
[R1-rip-1]network 12.0.0.0
[R1-rip-1]network 172.16.0.0
[R2]rip 1     
[R2-rip-1]version 2
[R2-rip-1]network 12.0.0.0
[R2-rip-1]network 23.0.0.0
[R3]rip 1 
[R3-rip-1]version 2
[R3-rip-1]network 23.0.0.0
[R3-rip-1]network 172.16.0.0
[R1]display ip routing-table protocol rip
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
23.0.0.0/8   RIP     100  1           D   12.1.1.2        GigabitEthernet0/0/0
172.16.6.0/24  RIP     100  2           D   12.1.1.2        GigabitEthernet0/0/0
172.16.7.0/24  RIP     100  2           D   12.1.1.2        GigabitEthernet0/0/0  
[R2]display ip routing-table protocol rip
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
172.16.1.0/24  RIP     100  1           D   12.1.1.1        GigabitEthernet0/0/0
172.16.2.0/24  RIP     100  1           D   12.1.1.1        GigabitEthernet0/0/0
172.16.6.0/24  RIP     100  1           D   23.1.1.3        GigabitEthernet0/0/1
172.16.7.0/24  RIP     100  1           D   23.1.1.3        GigabitEthernet0/0/1
[R3]display ip routing-table protocol rip
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
12.0.0.0/8   RIP     100  1           D   23.1.1.2        GigabitEthernet0/0/1
172.16.1.0/24  RIP     100  2           D   23.1.1.2        GigabitEthernet0/0/1
172.16.2.0/24  RIP     100  2           D   23.1.1.2        GigabitEthernet0/0/1

1）RIPV2支持路由自动汇总

[R1]display rip
Public VPN-instance    
    RIP process : 1
       RIP version   : 2
       Preference    : 100
       Checkzero     : Enabled
       Default-cost  : 0
       Summary       : Enabled

2）查看接口防环机制

[R1]display rip 1 interface GigabitEthernet 0/0/0 verbose 
 GigabitEthernet0/0/0(12.1.1.1)
  State           : UP          MTU    : 500
  Metricin        : 0       
  Metricout       : 1       
  Input           : Enabled     Output : Enabled     
  Protocol        : RIPv2 Multicast
  Send version    : RIPv2 Multicast Packets 
  Receive version : RIPv2 Multicast and Broadcast Packets
  Poison-reverse                : Disabled 
  Split-Horizon                 : Enabled

3）关闭R1的GigabitEthernet0/0/0接口防环机制，查看R2的RIP路由信息，实现了路由汇总功能。

[R1-GigabitEthernet0/0/0]undo rip split-horizon
[R1]display rip 1 interface GigabitEthernet 0/0/0 verbose 
 Split-Horizon                 : Disabled
[R2]display ip routing-table protocol rip
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
172.16.0.0/16  RIP     100  1           D   12.1.1.1        GigabitEthernet0/0/0
172.16.6.0/24  RIP     100  1           D   23.1.1.3        GigabitEthernet0/0/1
172.16.7.0/24  RIP     100  1           D   23.1.1.3        GigabitEthernet0/0/1

4）开启R1的GigabitEthernet0/0/0接口防环机制，使用summary always命令使得路由器不受水平分割活毒性逆转限制，都执行路由汇总功能。

[R1]interface GigabitEthernet 0/0/0
[R1-GigabitEthernet0/0/0]undo rip split-horizon
[R1]rip 1
[R1-rip-1]summary always 
[R3]rip 1
[R3-rip-1]summary always 
[R2]display ip routing-table protocol rip
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
172.16.0.0/16  RIP     100  1           D   23.1.1.3        GigabitEthernet0/0/1
         RIP     100  1           D   12.1.1.1        GigabitEthernet0/0/0

5）为防止自动汇总产生的路由产生的不精确问题，配置手工路由汇总。

[R1-GigabitEthernet0/0/0]rip summary-address 172.16.0.0 255.255.252.0
[R3-GigabitEthernet0/0/1]rip summary-address 172.16.4.0 255.255.252.0
[R2]display ip routing-table protocol rip            
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
172.16.0.0/22  RIP     100  1           D   12.1.1.1        GigabitEthernet0/0/0
172.16.4.0/22  RIP     100  1           D   23.1.1.3        GigabitEthernet0/0/1

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