Ethereal-users: Re: [Ethereal-users] Decode RTP version 1

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From: Jaap Keuter <jaap.keuter@xxxxxxxxx>
Date: Fri, 16 Dec 2005 09:41:09 +0100 (CET)
On Thu, 15 Dec 2005, Rui Manuel Ferreira Bernardo wrote:

> Im doing some test with multicast IPv6, and view the package in ethereal. (i
> used VLC for stream). I see IPv6-UDP, but i dont? found RTP package.
>
> So, i told Ethereal to ? Decode as ? RTP. But etheral doesn?t show
> me the entire package. Only appear the version field (01.. .... = Version:
> First draft Version(1)) and nothing else. Is this a bug? RFC 1889 isn?t
> implemented by ethereal, or this is a VLC bug?

Hi,

From RFC 3550:

   version (V): 2 bits
      This field identifies the version of RTP.  The version defined by
      this specification is two (2).  (The value 1 is used by the first
      draft version of RTP and the value 0 is used by the protocol
      initially implemented in the "vat" audio tool.)

From the source code:

 * This doesn't dissect older versions of RTP, such as:
 *
 *    the vat protocol ("version 0") - see
 *
 *      ftp://ftp.ee.lbl.gov/conferencing/vat/alpha-test/vatsrc-4.0b2.tar.gz
 *
 *    and look in "session-vat.cc" if you want to write a dissector
 *    (have fun - there aren't any nice header files showing the packet
 *    format);
 *
 *    version 1, as documented in
 *
 *      ftp://gaia.cs.umass.edu/pub/hgschulz/rtp/draft-ietf-avt-rtp-04.txt
 */

So it seems that the version field says that it's using an old draft RTP
version.

Thanx,
Jaap