Cisco CDP协议 | IT学习乐园

Cisco CDP协议

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Cisco CDP是 Cisco公司私有的协议。CDP思科发现协议。Cisco discovery protocol. Cisco IOS 10.3 以后的版本才有此协议。CDP是二层协议.CDP的默认更新时间为60秒，保持时间为180秒.

网络拓朴如下：

Router1 S0/0 <----> Router2 S0/0
Router1 F1/0 <----> Switch1 F0/0
Router2 F1/0 <----> Switch2 F0/0

Router1配置如下：

R1#show running-config
Building configuration...

Current configuration : 1295 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$mceS$BOoZJ5Pp/7QwSE6GJgnIq/
enable password 7 030752180500
!
no aaa new-model
!
resource policy
!
memory-size iomem 5
!
!
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
username builder privilege 10 password 7 1415070200002F39
!
!
!
!
!
!
interface Serial0/0
bandwidth 64
ip address 192.168.1.1 255.255.255.0
serial restart-delay 0
clock rate 64000
no dce-terminal-timing-enable
!
interface Serial0/1
no ip address
shutdown
serial restart-delay 0
no dce-terminal-timing-enable
!
interface Serial0/2
no ip address
shutdown
serial restart-delay 0
no dce-terminal-timing-enable
!
interface Serial0/3
no ip address
shutdown
serial restart-delay 0
no dce-terminal-timing-enable
!
interface FastEthernet1/0
ip address 192.168.2.1 255.255.255.0
duplex auto
speed auto
!
ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
banner motd ^C Welcome to connect to Router1! ^C
privilege exec level 10 show
!
line con 0
exec-timeout 0 0
password 7 030752180500
logging synchronous
login
line aux 0
line vty 0 4
exec-timeout 0 0
password 7 045802150C2E
login

Router2的配置如下:

R2#show running-config
Building configuration...

Current configuration : 1122 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$rfd5$/0v212MLcNsfWPmQNceVi0
enable password 7 05080F1C2243
!
no aaa new-model
!
resource policy
!
memory-size iomem 5
!
!
ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface Serial0/0
ip address 192.168.1.2 255.255.255.0
serial restart-delay 0
no dce-terminal-timing-enable
!
interface Serial0/1
no ip address
shutdown
serial restart-delay 0
no dce-terminal-timing-enable
!
interface Serial0/2
no ip address
shutdown
serial restart-delay 0
no dce-terminal-timing-enable
!
interface Serial0/3
no ip address
shutdown
serial restart-delay 0
no dce-terminal-timing-enable
!
interface FastEthernet1/0
ip address 192.168.3.1 255.255.255.0
duplex auto
speed auto
!
ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
password 7 0822455D0A16
logging synchronous
line aux 0
line vty 0 4
exec-timeout 0 0
password 7 01100F175804
login

Switch1配置如下:

SW1#show running-config
Building configuration...

Current configuration : 1134 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname SW1
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$WfhL$sQH6sKkChGMoLeUHRsHIE1
enable password 7 14141B180F0B
!
no aaa new-model
!
resource policy
!
memory-size iomem 5
no ip routing
!
!
no ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
!
interface FastEthernet0/1
!
interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
!
interface FastEthernet0/5
!
interface FastEthernet0/6
!
interface FastEthernet0/7
!
interface FastEthernet0/8
!
interface FastEthernet0/9
!
interface FastEthernet0/10
!
interface FastEthernet0/11
!
interface FastEthernet0/12
!
interface FastEthernet0/13
!
interface FastEthernet0/14
!
interface FastEthernet0/15
!
interface Vlan1
no ip address
no ip route-cache
!
ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
password 7 1511021F0725
logging synchronous
line aux 0
line vty 0 4
exec-timeout 0 0
password 7 110A1016141D
login

Switch2配置如下:

SW2#show running-config
Building configuration...

Current configuration : 1134 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname SW2
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$iG2H$s2fYXaoQKd.M9yX36qdom1
enable password 7 121A0C041104
!
no aaa new-model
!
resource policy
!
memory-size iomem 5
no ip routing
!
!
no ip cef
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
!
interface FastEthernet0/1
!
interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
!
interface FastEthernet0/5
!
interface FastEthernet0/6
!
interface FastEthernet0/7
!
interface FastEthernet0/8
!
interface FastEthernet0/9
!
interface FastEthernet0/10
!
interface FastEthernet0/11
!
interface FastEthernet0/12
!
interface FastEthernet0/13
!
interface FastEthernet0/14
!
interface FastEthernet0/15
!
interface Vlan1
no ip address
no ip route-cache
!
ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
exec-timeout 0 0
password 7 01100F175804
logging synchronous
line aux 0
line vty 0 4
exec-timeout 0 0
password 7 121A0C041104
login

===============================

获取CDP更新定时器和抑制时间（保持时间）信息

R1# show cdp
Global CDP information:
        Sending CDP packets every 60 seconds           %每60秒发送一次更新包
        Sending a holdtime value of 180     seconds　　%保持时间为180秒
        Sending CDPv2 advertisements is enabled        %以版本2广播方式发送
R1#

-------------- 修改更新定时器和保持时间。

R1#
R1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#cdp ?
advertise-v2      CDP sends version-2 advertisements
holdtime          Specify the holdtime (in sec) to be sent in packets
log               Log messages generated by CDP
run               Enable CDP
source-interface Insert the interface's IP in all CDP packets
timer             Specify rate (in sec) at which CDP packets are sent

R1(config)#cdp timer ?
<5-254> Rate at which CDP packets are sent (in sec)

R1(config)# cdp timer 90
R1(config)#cdp holdtime ?
<10-255> Length of time (in sec) that receiver must keep this packet

R1(config)# cdp holdtime 240
R1(config)#do show cdp
Global CDP information:
        Sending CDP packets every 90 seconds
        Sending a holdtime value of 240 seconds
        Sending CDPv2 advertisements is enabled
R1(config)#

显示邻居信息(CDP协议只能显示直接相连的邻居信息)
-------------------

R1#show cdp ?
entry      Information for specific neighbor entry
interface CDP interface status and configuration
neighbors CDP neighbor entries
traffic    CDP statistics
|          Output modifiers
<cr>

R1#show cdp neighbors
Capability 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 ID
SW1              Fas 1/0            126         S I       3640      Fas 0/0
R2               Ser 0/0            149        R S I      3640      Ser 0/0
R1#

--Device ID: 直连设备的主机名
--Local interface :要接收CDP分组的端口或接口（直接控制的本地设备）
--Holdtime :如果没有接收到其他CDP分组，路由器在丢弃接收到的信息之前将要保存的时间。
--Capability :邻居设备的类型，如路由器，交换机或中继器。
--Platform :CISCO设备类型在上面的输出中cisco 3640是直连在路由器R1上的设备。
--Port ID :与路由器R1直接相连的设备在发送更新时所用的接口

-------------

R1#show cdp neighbors ?
Async              Async interface
BVI                Bridge-Group Virtual Interface
CDMA-Ix            CDMA Ix interface
CTunnel            CTunnel interface
Dialer             Dialer interface
FastEthernet       FastEthernet IEEE 802.3
Lex                Lex interface
MFR                Multilink Frame Relay bundle interface
Multilink          Multilink-group interface
Serial             Serial
Tunnel             Tunnel interface
Vif                PGM Multicast Host interface
Virtual-PPP        Virtual PPP interface
Virtual-Template   Virtual Template interface
Virtual-TokenRing Virtual TokenRing
detail             Show detailed information
|                  Output modifiers
<cr>

R1#show cdp neighbors detail
-------------------------
Device ID: SW1
Entry address(es):
Platform: Cisco 3640, Capabilities: Switch IGMP
Interface: FastEthernet1/0, Port ID (outgoing port): FastEthernet0/0
Holdtime : 136 sec

Version :
Cisco IOS Software, 3600 Software (C3640-JK9O3S-M), Version 12.4(7a), RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2006 by Cisco Systems, Inc.
Compiled Mon 24-Apr-06 23:37 by ssearch

advertisement version: 2
VTP Management Domain: ''
Duplex: full

-------------------------
Device ID: R2
Entry address(es):
IP address: 192.168.1.2
Platform: Cisco 3640, Capabilities: Router Switch IGMP
Interface: Serial0/0, Port ID (outgoing port): Serial0/0
Holdtime : 157 sec

advertisement version: 2
VTP Management Domain: '

--------------------------

Show cdp entry *命令与show cdp neighbor details命令所显示相同的信息。

R1#show cdp entry ?
* all CDP neighbor entries
WORD Name of CDP neighbor entry

R1#show cdp entry *
-------------------------
Device ID: SW1
Entry address(es):
Platform: Cisco 3640, Capabilities: Switch IGMP
Interface: FastEthernet1/0, Port ID (outgoing port): FastEthernet0/0
Holdtime : 121 sec

advertisement version: 2
VTP Management Domain: ''
Duplex: full

advertisement version: 2
VTP Management Domain: ''

R1#

---只显示R2的信息，可用如下命令

R1#show cdp entry ?
* all CDP neighbor entries
WORD Name of CDP neighbor entry

R1#show cdp entry R2

advertisement version: 2
VTP Management Domain: ''

R1#

-----------------------------------

显示CDP统计信息

R2#show cdp ?
entry      Information for specific neighbor entry
interface CDP interface status and configuration
neighbors CDP neighbor entries
traffic    CDP statistics
|          Output modifiers
<cr>

R2#show cdp traffic
CDP counters :
        Total packets output: 120, Input: 110
        Hdr syntax: 0, Chksum error: 0, Encaps failed: 0
        No memory: 0, Invalid packet: 0, Fragmented: 0
        CDP version 1 advertisements output: 0, Input: 0
        CDP version 2 advertisements output: 120, Input: 110
R2#

清除CDP统计信息 clear cdp counters

R2#clear cdp ?
counters Clear CDP counters
table Clear cdp table

R2#clear cdp counter
R2#show cdp traffic
CDP counters :
        Total packets output: 0, Input: 0
        Hdr syntax: 0, Chksum error: 0, Encaps failed: 0
        No memory: 0, Invalid packet: 0, Fragmented: 0
        CDP version 1 advertisements output: 0, Input: 0
        CDP version 2 advertisements output: 0, Input: 0
R2#

清除CDP邻居表

R2#
R2#show cdp neighbors
Capability 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 ID
SW2              Fas 1/0            163         S I       3640      Fas 0/0
R1               Ser 0/0            180        R S I      3640      Ser 0/0
R2#clear cdp tab
R2#clear cdp table
R2#show cdp ne
R2#show cdp neighbors
Capability 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 ID
R2#

-------------------

显示CDP接口信息

R1#show cdp interface
Serial0/0 is up, line protocol is up
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/1 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/2 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/3 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
FastEthernet1/0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
R1#

R2#show cdp interface
Serial0/0 is up, line protocol is up
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/1 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/2 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/3 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet1/0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
R2#

R2#show cdp interface
Serial0/0 is up, line protocol is up
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/1 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/2 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0/3 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet1/0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
R2#

SW1#show cdp interface
FastEthernet0/0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/1 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/2 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/3 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/4 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/5 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/6 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/7 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/8 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/9 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/10 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/11 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/12 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/13 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/14 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
FastEthernet0/15 is up, line protocol is down
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
SW1#
SW1#

==================================

禁用和开启CDP，CDP默认状态是开启的。

在端口禁用CDP。 no cdp enable

R1#show ip interface brief
Interface                  IP-Address      OK? Method Status                Protocol
Serial0/0                  192.168.1.1     YES manual up                    up
Serial0/1                  unassigned      YES NVRAM administratively down down
Serial0/2                  unassigned      YES NVRAM administratively down down
Serial0/3                  unassigned      YES NVRAM administratively down down
FastEthernet1/0            192.168.2.1     YES manual up                    up
R1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#interface s0/0
R1(config-if)#no cdp ?
enable Enable CDP on interface
log     Log messages generated by CDP

R1(config-if)#no cdp enable
R1(config-if)#^Z
R1#

验证(未发现Serial0/0接口)

R1#show cdp interface
Serial0/1 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/2 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/3 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
FastEthernet1/0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
R1#

------------------

R2#show cdp neighbors
Capability 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 ID
SW2 Fas 1/0 145 S I 3640 Fas 0/0
R2#

-----------------

R1#show cdp neighbors
Capability 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 ID
SW1 Fas 1/0 153 S I 3640 Fas 0/0
R1#

在接口上开启CDP　cdp enable

R1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#interface serial 0/0
R1(config-if)#cdp ?
enable Enable CDP on interface
log Log messages generated by CDP

R1(config-if)#cdp enable
R1(config-if)#^Z
R1#
*Mar 1 03:31:51.263: %SYS-5-CONFIG_I: Configured from console by console

验证
R1#show cdp interface
Serial0/0 is up, line protocol is up
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/1 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/2 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
Serial0/3 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
FastEthernet1/0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 90 seconds
Holdtime is 240 seconds
R1#

------------

关闭整个设备上的CDP， no cdp run

R1(config)#cdp ?
advertise-v2      CDP sends version-2 advertisements
holdtime          Specify the holdtime (in sec) to be sent in packets
log               Log messages generated by CDP
run               Enable CDP
source-interface Insert the interface's IP in all CDP packets
timer             Specify rate (in sec) at which CDP packets are sent

R1(config)#no cdp run
R1(config)#^Z
R1#
*Mar 1 04:10:20.438: %SYS-5-CONFIG_I: Configured from console by console
R1#show cdp interface
% CDP is not enabled
R1#

如果整个设备上禁用CDP协议，不能在接口上开启CDP协议

R1#show cdp interface
% CDP is not enabled
R1#show cdp ne
R1#show cdp neighbors
% CDP is not enabled
R1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#
R1(config)#
R1(config)#interface serial0/0
R1(config-if)#cdp enable
% Cannot enable CDP on this interface, since CDP is not running
R1(config-if)#
R1(config-if)#

=========================

CDP的调试

SW1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
SW1(config)#no cdp run
SW1(config)#^Z
SW1#

R1#debug cdp packets
CDP packet info debugging is on
R1#
*Mar 1 04:28:36.750: CDP-PA: Packet received from R2 on interface Serial0/0
*Mar 1 04:28:36.750: **Entry found in cache**
R1#
*Mar 1 04:29:17.718: CDP-PA: version 2 packet sent out on Serial0/0
*Mar 1 04:29:17.726: CDP-PA: version 2 packet sent out on FastEthernet1/0
R1#
*Mar 1 04:29:36.750: CDP-PA: Packet received from R2 on interface Serial0/0
*Mar 1 04:29:36.750: **Entry found in cache**
R1#
*Mar 1 04:30:36.766: CDP-PA: Packet received from R2 on interface Serial0/0
*Mar 1 04:30:36.766: **Entry found in cache**
R1#

R1#no debug cdp pa
R1#no debug cdp packets
CDP packet info debugging is off
R1#

CDP事件调试

R1#debug cdp events
CDP events debugging is on
R1#
*Mar 1 04:35:36.766: CDP-EV: Lookup for ip phone with idb= Serial0/0 ip= 192.168.1.2 mac= 0000.0000.0000 platform= Cisco 3640
R1#
*Mar 1 04:36:36.742: CDP-EV: Lookup for ip phone with idb= Serial0/0 ip= 192.168.1.2 mac= 0000.0000.0000 platform= Cisco 3640
R1#undebug all
All possible debugging has been turned off
R1#

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