CCNP实验---EIGRP自动汇总

拓扑：

R1:
interface FastEthernet0/0
 ip address 172.16.1.254 255.255.255.0
 duplex auto
 speed auto

interface Serial2/0
 ip address 10.1.1.1 255.255.255.252
 serial restart-delay 0

router eigrp 100
 network 0.0.0.0
  auto-summary

R2:
interface FastEthernet0/0
 ip address 172.16.2.254 255.255.255.0
 duplex auto
 speed auto
    
interface Serial2/0
 ip address 10.1.1.2 255.255.255.252
 serial restart-delay 0
 clock rate 64000
           
router eigrp 100
 network 0.0.0.0
  auto-summary   

    

PC1:
interface FastEthernet0/0
 ip address 172.16.1.1 255.255.255.0
 duplex auto
 speed auto

ip default-gateway 172.16.1.254

 

PC2:
interface FastEthernet0/0
 ip address 172.16.2.1 255.255.255.0
 duplex auto
 speed auto

ip default-gateway 172.16.2.254

 

R1：ip route
     172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
D       172.16.0.0/16 is a summary, 00:06:32, Null0
C       172.16.1.0/24 is directly connected, FastEthernet0/0
     10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C       10.1.1.0/30 is directly connected, Serial2/0
D       10.0.0.0/8 is a summary, 00:06:46, Null0

 

R2: ip route
     172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
D       172.16.0.0/16 is a summary, 00:06:56, Null0
C       172.16.2.0/24 is directly connected, FastEthernet0/0
     10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C       10.1.1.0/30 is directly connected, Serial2/0
D       10.0.0.0/8 is a summary, 00:06:56, Null0

 

很明显，现在PC1和PC2不能ping通。
下面来关闭EIGRP的auto-summary

R1(config)#
R1(config)#router eigrp 100
R1(config-router)#no auto-summary

R2(config)#router eigrp 100
R2(config-router)#
R2(config-router)#no auto-summary

 

R1:
interface FastEthernet0/0
 ip address 172.16.1.254 255.255.255.0
 duplex auto
 speed auto

interface Serial2/0
 ip address 10.1.1.1 255.255.255.252
 serial restart-delay 0

router eigrp 100
 network 0.0.0.0
  no auto-summary

 

R2:
interface FastEthernet0/0
 ip address 172.16.2.254 255.255.255.0
 duplex auto
 speed auto
    
interface Serial2/0
 ip address 10.1.1.2 255.255.255.252
 serial restart-delay 0
 clock rate 64000
           
router eigrp 100
 network 0.0.0.0
  no auto-summary   

 

R1: ip route
     172.16.0.0/24 is subnetted, 2 subnets
C       172.16.1.0 is directly connected, FastEthernet0/0
D       172.16.2.0 [90/2172416] via 10.1.1.2, 00:01:44, Serial2/0
     10.0.0.0/30 is subnetted, 1 subnets
C       10.1.1.0 is directly connected, Serial2/0

 

R2: ip route
     172.16.0.0/24 is subnetted, 2 subnets
D       172.16.1.0 [90/2172416] via 10.1.1.1, 00:02:21, Serial2/0
C       172.16.2.0 is directly connected, FastEthernet0/0
     10.0.0.0/30 is subnetted, 1 subnets
C       10.1.1.0 is directly connected, Serial2/0

 

经验证，现在PC1，和PC2能正常通信。

总结：
1.EIGRP自动汇总，默认下为打开的
2.EIGRP自动汇总会将主类网络汇总，从而使部分网络不能通信。
3.建议关闭EIGRP自动汇总，通过手工来对其汇总。