Wireless Datagram Protocol (WDP)

The Wireless Datagram Protocol provides a UDP-like service to non-IP bearers. On IP-enabled bearers (like IP or GSM Circuit-Switched Data (CSD) or even GPRS) WDP is identical to UDP, hence people often talk about the "WDP-UDP" protocol.

WDP provides 16-bit port multiplexing and 8-bit data transport in the same way UDP does.

Note that WDP is not a real dissector in Wireshark, but some dissectors (like the GSM SMS User Data dissector) will hand off protocol data to WAP dissectors as if it was handed off to a WDP dissector.

History

WDP was added to the WAP specifications as at the time of writing the first WAP specifications there was a plethora of wireless datagram transfer protocols (TETRA, Mobitex, IDEN, GSM SMS and many others) but no-one could be used the same way for offering the WAP services.

As a result, WDP provides adaptation to the relevant protocols in order to enable them to convey the WAP protocols.

Protocol dependencies

The WAP transport protocol stack is shown below:

WapProtocolFamily/WAP_Transport_Protocol_Stacks.jpg

Depending on the protocol stack, 4 different standard WDP (UDP) ports have been defined: 9200, 9201, 9202 and 9203. WSP can run on other ports too.

Example traffic

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

Wireshark

The WDP dissector does not really exist in Wireshark.

Preference Settings

The WDP dissector does not exist (not needed) and consequently it has no preference settings.

Example capture file

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

Display Filter

WDP traffic cannot be filtered directly with Wireshark. However, if the non-IP bearer is known, then filtering on that bearer and WSP may show the traffic where WDP exists.

Capture Filter

You cannot directly filter WDP while capturing. However, if you know the non-IP bearer used (see above), you might filter on that one (e.g., by using the TCP port of the SMPP protocol in case of transport over SMPP).

Discussion

Wireless_Datagram_Protocol (last edited 2008-04-12 17:49:43 by localhost)