CCNA考題分析:理解Show IP route命令

字號:

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?
    A. 120 is the bandwidth allocation and 3 is the routing process number.
    B. 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.
    作為Pcjob的網(wǎng)絡(luò)管理員,你正在為路由器排錯,你在其中的一臺路由器使用show ip route命令,輸出的結(jié)果如上圖,[120/3]描述的是什么意思?
    正確答案:B
    解釋:
    路由器的IOS使用一個名為Administrative Distance(管理距離)的概念來決定使用哪一個路由。Admininstrative distance表示的是一個單獨(dú)路由器中所有路由協(xié)議的可信度的這樣一個數(shù)值,數(shù)值越低越好,也就是說,數(shù)值越低,路由協(xié)議可信度越高。
    Route Type Administrative Distance
    • Connected 0
    • IGRP 100
    • RIP 120
    參考資料:
    CCNA Self-Study CCNA ICND exam certification Guide (Cisco press, ISBN 1-58720-083-X) Page 177