Protocol CDP

[zakariayardi]

Hi,

I want to know some informations about protocol CDP. Why is used? packet format? and why we use the MAC destination addr 01:00:0c:cc:cc:cc?

Thanks

[Reza Sharifi]

Hi,

Cisco devices send CDP announcements to the multicast destination address 01-00-0c-cc-cc-cc, out each connected network interface. These multicast packets may be received by Cisco switches and other networking devices that support CDP into their connected network interface. This multicast destination is also used in other Cisco protocols such as VTP. By default, CDP announcements are sent every 60 seconds on interfaces that support Subnetwork Access Protocol (SNAP) headers, including Ethernet, Frame Relay and Asynchronous Transfer Mode (ATM). Each Cisco device that supports CDP stores the information received from other devices in a table that can be viewed using the show cdp neighbors command. This table is also accessible via snmp.

More info:

http://network.spravcesite.net/subdom/network/index.php?id=cdp

HTH

[zakariayardi]

thanks Reza for your help.

In reality I found those information on the Net, but I search for more specific information about this protocol.