-------------问一个关于EIGRP度量的问题-----------

I.83

Refer to the exhibit. All interfaces have been configured with the bandwidths that are shown in the exh
Assuming that all routers are using a default configuration of EIGRP as their routing protocol, what pa
packets take ** the 172.16.1.0/16 network to the 192.168.200.0/24 network?

1.A,B,E
2.A,C,E
3.A,D,E
4.Packets will load balance across the A,B,E and A,C,E paths.
5.Packets will load balance across the A,B,E and A,D,E paths.
6.Packets will load balance across the A,C,E and A,D,E paths.

答案选1 我想知道为什么？ 不是应给选低带宽的这样所有高度量值么？我觉得应该是2
谢谢~~~

王晓强

eigrp到一个远程网络的Metric值为下一跳路由器的ad，和本地路由器到下一跳路由器的metric值相加得到也就是fd。
用show interface 接口名命令可以查看到以上数值，Bandwidth默认是接口里带宽，但是当我们在接口上修改Bandwidth值的时候，并不会影响到接口真正的物理带宽，Bandwidth就是给路由协议算尺度的一个参数。

admin

因该选1 因为那条路经的带宽开销最小

广播风暴

在接口修改了带宽，影响本地到邻居的开销。
如图~~要比较3条路径的总开销，是比较每条路径中的瓶颈~~也就是最小带宽，而ABE这个路径的最小带宽是512 比其他几条的最小带宽要大~~这里又是所有接口都配置了如图的带宽，所以将导致上面的路径的FD是最小的。
综上~~答案1是正确的。

如图所示如正常配置
R1的路由表：
R1#sh ip ro
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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
     34.0.0.0/24 is subnetted, 1 subnets
D       34.1.1.0 [90/2681856] via 13.1.1.3, 00:00:05, Serial0/3
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
     4.0.0.0/24 is subnetted, 1 subnets
D       4.4.4.0 [90/2809856] via 13.1.1.3, 00:00:05, Serial0/3
                [90/2809856] via 12.1.1.2, 00:00:05, Serial0/2
     24.0.0.0/24 is subnetted, 1 subnets
D       24.1.1.0 [90/2681856] via 12.1.1.2, 00:00:05, Serial0/2
     12.0.0.0/24 is subnetted, 1 subnets
C       12.1.1.0 is directly connected, Serial0/2
     13.0.0.0/24 is subnetted, 1 subnets
C       13.1.1.0 is directly connected, Serial0/3
R4的路由表：
R4#sh ip ro
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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
     34.0.0.0/24 is subnetted, 1 subnets
C       34.1.1.0 is directly connected, Serial0/3
     1.0.0.0/24 is subnetted, 1 subnets
D       1.1.1.0 [90/2809856] via 34.1.1.3, 00:11:25, Serial0/3
                [90/2809856] via 24.1.1.2, 00:11:25, Serial0/2
     4.0.0.0/24 is subnetted, 1 subnets
C       4.4.4.0 is directly connected, Loopback0
     24.0.0.0/24 is subnetted, 1 subnets
C       24.1.1.0 is directly connected, Serial0/2
     12.0.0.0/24 is subnetted, 1 subnets
D       12.1.1.0 [90/2681856] via 24.1.1.2, 00:00:50, Serial0/2
     13.0.0.0/24 is subnetted, 1 subnets
D       13.1.1.0 [90/2681856] via 34.1.1.3, 00:11:25, Serial0/3

如果在R1的接口改动带宽~~
R1#sh ip ro
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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

     34.0.0.0/24 is subnetted, 1 subnets
D       34.1.1.0 [90/2681856] via 13.1.1.3, 00:00:01, Serial0/3
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
     4.0.0.0/24 is subnetted, 1 subnets
D       4.4.4.0 [90/2809856] via 13.1.1.3, 00:00:01, Serial0/3
     24.0.0.0/24 is subnetted, 1 subnets
D       24.1.1.0 [90/3193856] via 13.1.1.3, 00:00:01, Serial0/3
     12.0.0.0/24 is subnetted, 1 subnets
C       12.1.1.0 is directly connected, Serial0/2
     13.0.0.0/24 is subnetted, 1 subnets
C       13.1.1.0 is directly connected, Serial0/3
这时R4上不做改动：
R4#sh ip ro
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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
     34.0.0.0/24 is subnetted, 1 subnets
C       34.1.1.0 is directly connected, Serial0/3
    1.0.0.0/24 is subnetted, 1 subnets
D       1.1.1.0 [90/2809856] via 34.1.1.3, 00:11:25, Serial0/3
                [90/2809856] via 24.1.1.2, 00:11:25, Serial0/2
     4.0.0.0/24 is subnetted, 1 subnets
C       4.4.4.0 is directly connected, Loopback0
     24.0.0.0/24 is subnetted, 1 subnets
C       24.1.1.0 is directly connected, Serial0/2
     12.0.0.0/24 is subnetted, 1 subnets
D       12.1.1.0 [90/2681856] via 24.1.1.2, 00:00:50, Serial0/2
     13.0.0.0/24 is subnetted, 1 subnets
D       13.1.1.0 [90/2681856] via 34.1.1.3, 00:11:25, Serial0/3

[ 本帖最后由 广播风暴 于 2008-11-27 01:17 编辑 ]

[ 本帖最后由 广播风暴 于 2008-11-27 01:21 编辑 ]

bookpig

讨论很激烈！……

I.83

明白了！谢谢大家！