怎样理解ShowIProute命令

会计考友

You are a network administrator at Pcjob. You are troubleshooting a router problem. You issue the show ip route command on one of the routers. The output from the command is shown in the following exhibit:
What does [120/3] represent?
) ^5 T% Z* ?" d+ B0 Q) {- FA. 120 is the bandwidth allocation and 3 is the routing process number.
# v8 w8 w3 d: i- V8 eB. 120 is the administrative distance and 3 is the metric for that route.
C. 120 is the value of the update timer and 3 is the number of updates received.
D. 120 is the UDP port for forwarding traffic and 3 is the number of bridges.
  t4 h4 w3 J0 J% z: y
6 J. B+ q( r) j9 _　　作为Pcjob的收集打点员，你正在为路由器排错，你在其中的一台路由器使用show ip route呼吁，输出的结不美观如上，[120/3]描述的是什么意思？

正确谜底：B
0 O& q4 T: t7 L5 U$ [/ F5 X
8 Y. w! @! S9 c. m/ B9 I诠释：
% \! [) b8 G! w& Y2 h7 W1 d* e5 `　　路由器的IOS使用一个名为Administrative Distance(打点距离)的概念来抉择使用哪一个路由。Admininstrative distance暗示的是一个零丁路由器中所有路由和谈的可托度的这样一个数值，数质ё俳低越好，也就是说，数质ё俳低，路由和谈可托度越高。
0 T& @( J; p5 Y* w6 \9 y. |1 t( [Route Type Administrative Distance
? Connected 0
/ s, l4 E) Z9 E- D: ~' P3 Q9 f2 k0 W? IGRP 100
/ b- S. m  n) n? RIP 120

参考资料：
7 s1 a$ L# {4 [8 {- {0 d6 BCCNA Self-Study CCNA ICND exam certification Guide (Cisco press, ISBN 1-58720-083-X) Page 177