© 2006, shenzhen polytechnic. all rights reserved. 1 cisco 发现协议 cisco discovery protocol...

© 2006, Shenzhen Polytechnic. All rights reserved. 1

Cisco 发现协议Cisco Discovery Protocol

深圳职业技术学院计算机系网络专业

© 2006, Shenzhen Polytechnic. All rights reserved.. 2

教学目标（ Objectives ）

1. Cisco 发现协议特征（ Feature of Cisco Discovery Protocol ）

2.CDP 命令（ CDP Command ）3. 开启和关闭 CDP （ Enable and disable CDP ）4. 远程登录（ telnet ）


Cisco 发现协议（ Cisco Discovery Protocol ）

1.Cisco 提供的专有的命令CDP runs on all Cisco equipment 2. 获得直接连接的设备的信息摘要The primary use of CDP is to discover all Cisco devices that are directly connected to a local device. 3. 运行在数据链路层Cisco Discovery Protocol (CDP) is a Layer 2 protocol 4.Cdp 版本 1 在 10.3 版本后会自动启动CDP Version 1 is enabled by default with Cisco IOS (Release 10.3 later). 5.cdp 更新周期 60 秒CDP update timer is 60s6.cdp 过期周期 180 秒CDP hold timer is 180s


信息摘要包括（ Summary information includes ） :

• 设备 ID （ Device ID ） • 本地接口（ Local Interface ）• 保持时间（ Holdtime ）• 功能（ Capability ）• 平台（ Platform ）• 端口 ID （ Port ID ）• VTP 域名（ VTP Management

Domain Name (CDPv2 only) ）• 本征 VLAN （ Native VLAN

(CDPv2 only) ）• 全双工 / 半双工（ Full/Half-Duplex

(CDPv2 only) ）

CDP

show cdp

CDP

CDP

用 CDP 发现邻居（ Discovering Neighbors with CDP ）


Using the show cdp neighbor Command

RouterA#sh cdp neighborsCapability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port IDRouterB Ser 0 148 R 2522 Ser 1SwitchA Eth 0 167 T S 1900 2

SwitchBRouterA RouterBSwitchA

10.3.3.2 10.3.3.1 10.1.1.110.1.1.2

10.2.2.1 10.2.2.2

S0S1


Using the show cdp entry Command

RouterA#sh cdp entry *-------------------------Device ID: RouterB Entry address(es): IP address: 10.1.1.2 Platform: cisco 2522, Capabilities: Router Interface: Serial0, Port ID (outgoing port): Serial1Holdtime : 168 sec

Version :Cisco Internetwork Operating System Software IOS (tm) 2500 Software (C2500-JS-L), Version 12.0(3), RELEASE SOFTWARE (fci)Copyright (c) 1986-1999 by cisco Systems, Inc.Compiled Mon 08-Feb-99 18:18 by phanguye


10.3.3.2 10.3.3.1 10.1.1.110.1.1.2

10.2.2.1 10.2.2.2

S0S1


CDP 其它命令（ Additional CDP Commands ）

RouterA#sh cdp trafficCDP counters :

Packets output: 56, Input: 38Hdr syntax: 0, Chksum error: 0, Encaps failed: 3No memory: 0, Invalid packet: 0, Fragmented: 0

RouterA#sh cdp interface BRI0 is administratively down, line protocol is down Encapsulation HDLC Sending CDP packets every 60 seconds Holdtime is 180 seconds


10.3.3.2 10.3.3.1 10.1.1.110.1.1.2

10.2.2.1 10.2.2.2

S0S1


• 1. 在全局配置模式下使用（ no ） cdp run 命令开启或关闭所由接口的 CDP 功能。默认情况下， CDP 被全局开启。

• The cdp run command is used to enable CDP globally on the router. By default, CDP is globally enabled.

• 2. 在接口模式下使用（ no ） cdp enable 命令可以开启或关闭某个特定接口的 CDP 功能。

• CDP could be enabled on each of the devices interfaces by using the cdp enable command.

开启和关闭 CDP （ Enable and disable CDP ）


配置周期（ Configuring Timer ）

Router(config)#cdp timer 5

Router(config)# cdp holdtime 15


用 telnet 连接到远程主机（ Using Telnet to Connect to Remote Devices ）

Remote device


10.3.3.2 10.3.3.1 10.1.1.110.1.1.2

10.2.2.1 10.2.2.2

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RouterA#telnet 10.1.1.2

Trying 10.1.1.2 ... Open-------------------------------------------------Catalyst 1900 Management ConsoleCopyright (c) Cisco Systems, Inc. 1993-1998All rights reserved.Enterprise Edition SoftwareEthernet Address: 00-90-86-73-33-40PCA Number: 73-2239-06PCA Serial Number: FAA02359H8KModel Number: WS-C1924-ENSystem Serial Number: FAA0237X0FQ..RouterB>


查看 telnet 连接（ Viewing Telnet Connections ）


10.3.3.2 10.3.3.1 10.1.1.110.1.1.2

10.2.2.1 10.2.2.2

S0S1

RouterA#sh sessionConn Host Address Byte Idle Conn Name 1 10.1.1.2 10.1.1.2 0 1 10.1.1.2* 2 10.3.3.2 10.3.3.2 0 0 10.3.3.2

RouterA#sh user Line User Host(s) Idle Location* 0 con 0 10.1.1.2 3 10.3.3.2 2 11 vty 0 idle 1 10.1.1.2


挂起 telnet 会话（ Suspending a Telnet Session）


10.3.3.2 10.3.3.1 10.1.1.110.1.1.2

10.2.2.1 10.2.2.2

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RouterB#<Ctrl-Shift-6> xRouterA#sh sessionConn Host Address Byte Idle Conn Name 1 10.1.1.2 10.1.1.2 0 1 10.1.1.2RouterA#resume 1RouterB#


RouterA#disconnect Closing connection to 10.3.3.2 [confirm]

RouterA#clear line 11[confirm] [OK]

关闭 telnet 会话（ Closing a Telnet Session）

Closing a session opened by a remote device

Closing the current session opened by you


10.3.3.2 10.3.3.1 10.1.1.110.1.1.2

10.2.2.1 10.2.2.2

S0S1


思考题（ Questions ）

1 ． CDP 有哪些特征？2 ． CDP 的功能是什么？3 ．用 CDP 可以看到邻居的哪些信息？4 ．用什么命令可以在接口下控制 CDP 的启动？5 ．哪个符号是我们获得帮助时最常用的？6 ． telnet 默认支持几个用户同时登录？

© 2006, shenzhen polytechnic. all rights reserved. 1 cisco 发现协议 cisco discovery protocol...

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