实验7:CDP
1. 实验目的
通过本实验,读者可以掌握如下技能:
1) 查找CDP 邻居
2) 熟悉CDP 的配置
2. 实验拓扑
2-11 实验7 拓扑图
 
3. 实验步骤
1) 步骤1:打开接口
R1(config)#int g0/0
R1(config-if)#no shutdown
R1(config-if)#int s0/0/0
R1(config-if)#no shutdown
R2(config)#int g0/0
R2(config-if)#no shutdown
R2(config-if)#int s0/0/0
R2(config-if)#no shutdown
R2(config-if)#clock rate 128000
//以上是打开路由器间互连的各个接口,而默认时交换机S1 的所有接口就是打开的。
2) 步骤:查看CDP 配置
R1#show cdp
Global CDP information: Global CDP information:
Sending CDP packets every 60 seconds
Sending a holdtime value of 180 seconds
Sending CDPv2 advertisements is enabled
//默认时CDP 是运行的,每60 秒从接口发送cdp 消息;发送出的CDP 消息,邻居会为它保
180
R1#show cdp interface
GigabitEthernet0/0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
GigabitEthernet0/1 is administratively down, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/0/0 is down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/0/1 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
//以上显示在哪些接口运行CDP 协议
3) 步骤3:查看CDP 邻居
R1#show cdp neighbors
Device ID Local Intrfce Holdtme Capability Platform Port ID
R2 Ser 0/0/0 137 R S I 2821 Ser 0/0/0
S1 Gig 0/0 172 S I WS-C3560- Fas 0/1
//以上显示R1 路由器有两个邻居:R2 S1。“Device ID”表示邻居的主机名;“Local Intrfce
表明R1 通过该接口和邻居连接,注意是R1 上的接口;“Holdtme”指收到邻居发送的CDP
消息的时间,采用倒计时;“Capability”表明邻居是什么设备,第一、二行Capability Codes
对各符号进行了说明;“Platform”指明了邻居的硬件型号;“Port ID”指明了R1 是连接对
方的哪个接口上。
R1#show cdp entry R2
-------------------------
Device ID: R2
Entry address(es):
Platform: Cisco 2821, Capabilities: Router Switch IGMP
Interface: Serial0/0/0, Port ID (outgoing port): Serial0/0/0
Holdtime : 158 sec
Version :
Cisco IOS Software, 2800 Software (C2800NM-ADVENTERPRISEK9-M), Version 12.4(11)T1, RELEASE
SOFTWARE (fc5)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Thu 25-Jan-07 12:50 by prod_rel_team
advertisement version: 2
VTP Management Domain: ''
//以上是显示邻居R2 的详细信息,甚至可以知道邻居的IOS 版本
R1#clear cdp table
//清除CDP
4) 步骤4:关、启CDP;调整CDP 参数
R1(config)#int g0/0
R1(config-if)#no cdp enable
//以上是在g0/0 接口上关闭cdp,其他接口还运行CDP
R1(config-if)#exit
R1(config)#no cdp run //以上是在整个路由器上关闭cdp
R1(config)#cdp run //在整个路由器上打开cdp
R1(config)#cdp timer 30 //调整CDP 消息发送时间为30
R1(config)#cdp holdtime 120
//调整CDP 消息的holdtime 120 ,对方收到该路由器发送的CDP 消息后将保持120
R1#show cdp
Global CDP information:
Sending CDP packets every 30 seconds
Sending a holdtime value of 120 seconds
Sending CDPv2 advertisements is enabled