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Differences between revisions 4 and 6 (spanning 2 versions)
Revision 4 as of 2005-10-19 08:05:27
Size: 2077
Editor: GuyHarris
Comment: Fix Cisco HDLC link.
Revision 6 as of 2005-10-27 14:22:13
Size: 2073
Editor: ylin1
Deletions are marked like this. Additions are marked like this.
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(XXX add links to preference settings affecting how CDP is dissected). There are no CDP specific preference settings.
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 XXX }}}  ether host 01000ccccccc }}}

Cisco Discovery Protocol (CDP)

CDP (Cisco Discovery Protocol) is a Cisco proprietary protocol that runs between direct connected network entities (routers, switches, remote access devices, firewalls, etc.). The purpose of the protocol is to supply a network entity with information about its direct connected neighbors.


XXX - add a brief description of CDP history

Protocol dependencies

  • ["LLC"]/["SNAP"]: CDP is encapsulated as LLC/SNAP with an OUI of 0x00000C and a protocol ID of 0x2000.
  • ["Cisco HDLC"]: CDP is encapsulated over Cisco HDLC with a protocol type of 0x2000.
  • ["PPP"]: CDP is encapsulated over PPP with a protocol type of 0x0207.

Example traffic

XXX - Add example traffic here (as plain text or Ethereal screenshot).


The CDP dissector is (fully functional, partially functional, not existing, ... whatever the current state is). Also add info of additional Ethereal features where appropriate, like special statistics of this protocol.

Preference Settings

There are no CDP specific preference settings.

Example capture file

XXX - Add a simple example capture file to the SampleCaptures page and link from here (see below). Keep this file short, it's also a good idea to gzip it to make it even smaller, as Ethereal can open gzipped files automatically.

  • attachment:SampleCaptures/cdp.pcap

Display Filter

A complete list of CDP display filter fields can be found in the [ display filter reference]

  • Show only the CDP based traffic:


Capture Filter

XXX - filter for SNAP OUI/PID pair?

  • Capture only the CDP traffic:

     ether host 01000ccccccc 


CDP (last edited 2013-05-06 19:20:28 by clementc)