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Cisco Discovery Protocol used to negotiate and announce special attributes from one device to the other, Cisco invented it, but there is some other vendors use it or at least can understand it.
It is used to share information about other directly connected Cisco equipments.
it's a propriotary cisco protocol that detects directly connected devices their type model and function
cdp run to enable it
show cdp neighbor
show cdp neighbor detail
It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address. CDP can also be used for On-Demand Routing, which is a method of including routing information in CDP announcements so that dynamic routing protocols do not need to be used in simple networks.
As a brief useful ansewer cdp is powerful monitoring and troubleshoooting cisco proprietary tool that operates at datalink layer.
CDP can be used to build logical network topology if such network documentation is missing or lacking in detail.
ghenimi,
best regards.
The Cisco Discovery Protocol (CDP) is a proprietary Data Link Layer protocol developed by Cisco Systems. It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address
CDP is layer2 protocol used to discover devices directly Connected to the router ( name , type, @ ip ...) and it is generally used when layer3 connexion is failed ..the most used command is :
router # Show CDP neighbors details to see more details about devices like @IP..
it's a layer two protocol. it's used to share information about other directly connected Cisco devices for example if you execute the command "show cdp neighbor" in the privilege modem of a router it will show you the host name of the neighboring router, your interface that is connecting you to the other device as well as device interface toward you.
CDP stands for Cisco Discovery Prodocol.
Simply it discovers Cisco devices which are directly connected to its interface.
It is a Cisco proprietary Protocol.So it won't detetct other brands apart from Cisco.
It is important to note the following points:
a. Should be directly connected
b. It only detects Cisco devices (Also detetcs HP as HP has an agreement).However you have to install CDP into other brand if you want to detetct it by CDP
You can use following commands:
#sh cdp neighbours
#sh cdp attribute
Example:
switch# show cdp neighbors
Capability Codes: R - Router, T - Trans-Bridge, B - Source-Route-BridgeS - Switch, H - Host, I - IGMP, r - Repeater,V - VoIP-Phone, D - Remotely-Managed-Device,s - Supports-STP-Dispute, M - Two-port Mac Relay
Device ID Local Intrfce Hldtme Capability Platform Port ID
savbu-qa-dist-120 mgmt0177 S I WS-C3750E-24T Gig1/0/13
swor96(SSI13110AAQ) Eth1/17165 S I s N5K-C5010P-BF Eth1/19
swor96(SSI13110AAQ) Eth1/18165 S I s N5K-C5010P-BF Eth1/20
swor95(SSI13110AAS) Eth1/29171 S I s N5K-C5010P-BF Eth1/19
So, you can easily find out the name of Cisco device and see on which port it is connected.
CDP is enable by defult on all cisco devices. it is used for troubleshooting connectivity between Cisco Devices.To check the output of Cisco discovery protocol(CDP) use the following commands.
Syntax: show CDP.
To check the directly connected Cisco devices like hostname, interface to which it is connected, the model of the device ETC.
Syntax: show CDP Neighbour
This command will display Device id,Local interface, holdtime, capability,platform, and port id of the next switch to which the interface is connected.
If you want to know the detail information about the directly connected Cisco devices or neighbour like IP address IOS version,platform of the remote device etc.
use this command,
Syntax: show CDP neighbour detail.
It's used to discover another cisco devices and get general info.
