手动汇总特点:
1.减少路由条目。
2.减少正常数据的延时,
3.占用内存和CPU资源的减少。
4.减少带宽的占用。
 
拓扑如下:
 
 
 
实验:将R1上LoopBack 0,1,2三个接口地址汇总成一条路由
 
 
 
 
步骤一:首先我在R1R2之间做好基本配置并启用EIGRP发布网段
 
R1
 
Router>
Router>en
Router#conf t
Router(config)#hostname R1
R1(config)#interface f0/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no sh
R1(config)#interface loopback 0
R1(config-if)#ip address 172.16.1.1 255.255.255.0
R1(config-if)#int lo1
R1(config-if)#ip address 172.16.2.1 255.255.255.0
R1(config-if)#int lo2
R1(config-if)#ip address 172.16.3.1 255.255.255.0
R1(config-if)#exit
R1(config)#router eigrp 1
R1(config-router)#no auto-summary
R1(config-router)#network 192.168.1.0 0.0.0.255
R1(config-router)#network 172.16.1.0 0.0.0.255
R1(config-router)#network 172.16.2.0 0.0.0.255
R1(config-router)#network 172.16.3.0 0.0.0.255
R1(config-router)#end
R1#
 
 
 
 
 
R2
 
Router>
Router>en
Router#conf t
Router(config)#hostname R2
R2(config)#interface f0/0
R2(config-if)#ip address 192.168.1.2 255.255.255.0
R2(config-if)#no sh
R2(config-if)#exit
R2(config)#router eigrp 1
R2(config-router)#network 192.168.1.0 0.0.0.255
R2(config-router)#end
R2#
 
查看路由表:
 
R2#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
 
     172.16.0.0/24 is subnetted, 3 subnets
D       172.16.1.0 [90/156160] via 192.168.1.1, 00:00:17, FastEthernet0/0
D       172.16.2.0 [90/156160] via 192.168.1.1, 00:00:17, FastEthernet0/0
D       172.16.3.0 [90/156160] via 192.168.1.1, 00:00:17, FastEthernet0/0
C    192.168.1.0/24 is directly connected, FastEthernet0/0
R2#
 
注:在R2上面我们可以很清楚的看见从R1上面学到的3条明细路由.
 
 
 
 
 
 
步骤二:当我们在R1接口下做手工总汇总之后的变化.
 
 
R1
 
R1(config-if)#ip summary-address eigrp 1 172.16.0.0 255.255.252.0
//这个时候我把之前3个不同网段的条目汇总为掩码为:255.255.252.0的网段
R1(config-if)#end
R1#
 
 
注:现在我们来看下R2的变化. 
 
 
 
 
 
R2#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
 
     172.16.0.0/22 is subnetted, 1 subnets
D       172.16.0.0 [90/156160] via 192.168.1.1, 00:01:52, FastEthernet0/0
C    192.168.1.0/24 is directly connected, FastEthernet0/0
R2#
 
注:以之前相比可以看到现在学过来的是在R1上汇总之后的路由,它的掩码长度为/22,也就是我刚刚手动输入的子网掩码.
 
 
总结:
 
这样做在针对连续在子网,有很大的改善,通过减少路由表的条目来节约我们的硬件资源以及网络带宽.