本人刚开始学习思科技术,在做实验时碰到一个关于自动汇总的问题,想请教各位高手
拓扑图是这样的
当我在R2 R3上关闭自动汇总时,R1可以ping通R4,而且这个网络通信没有任何问题(我配的EIGRP协议)
R1的路由表也正常,为下列数据
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 2 subnets
D 172.16.20.0 [90/2221056] via 172.16.10.1, 00:00:54, Ethernet0/0
C 172.16.10.0 is directly connected, Ethernet0/0
10.0.0.0/24 is subnetted, 1 subnets
D 10.3.1.0 [90/2195456] via 172.16.10.1, 00:01:16, Ethernet0/0
R2的路由表
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 2 subnets
D 172.16.20.0 [90/2195456] via 10.3.1.2, 00:00:26, Serial1/0
C 172.16.10.0 is directly connected, Ethernet0/0
10.0.0.0/24 is subnetted, 1 subnets
C 10.3.1.0 is directly connected, Serial1/0
当我将自动汇总开启时
R1路由表
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.10.0 is directly connected, Ethernet0/0
D 10.0.0.0/8 [90/2195456] via 172.16.10.1, 00:00:44, Ethernet0/0
此时R1路由表中缺少了172.16.20.0项,即上面的红色项
R2路由表
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
C 172.16.10.0/24 is directly connected, Ethernet0/0
D 172.16.0.0/16 is a summary, 00:00:10, Null0
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.3.1.0/24 is directly connected, Serial1/0
D 10.0.0.0/8 is a summary, 00:00:39, Null0
由于本人是个菜鸟,所以也不怕大家笑话,有几个问题不太懂
1.当自动汇总开启时,R2路由表上Null0这两项是什么意思?
2.为什么自动汇总开启后,R1路由表上缺少了172.16.20.0的远程网络通告项,如果说由于自动汇总的关系,那不应该收到172.16.0.0的远程通告么?小弟不是很明白,希望高手能解答下