Wireshark · Ethereal-dev: Re: [Ethereal-dev] WTP/WSP Patch 2

[Guy Harris <gharris@xxxxxxxxx>]

On Tue, Jul 29, 2003 at 03:13:06PM -0700, Guy Harris wrote:
> 	3) I got rid of the "(last)" in the names of Segmented Invoke and 
> Segmented Reply (I'm not sure those are guaranteed to be the last 
> ones).

At least as I read section 8.14 of WAP-201-WTP Approved Version
19-February-2000, a segmented PDU is sent out as:

	an Invoke or Result PDU, which, by virtue of not being a
	Segmented Invoke or Segmented Result, is the first segment, and
	which does *not* have the TTR flag set (indicating that it's not
	the entire PDU);

	one or more Segmented Invoke or Segmented Result PDUs, with
	sequence numbers starting with 1 - the implied sequence number
	of the first segment is 0 - with the last of the Segmented
	Invoke/Segmented Result PDUs having the TTR flag set.

That suggests that the last one is the one with TTR set, and that the
others shouldn't be marked as "(last)".

It also suggests that a Segmented Invoke or Segmented Result is never
the first PDU, and should never have a sequence number of 0.  Does a
later version of the WTP spec say that they can have a sequence number
of 0?  (Your patch hands Segmented Invoke and Segmented Result packets
with a sequence number of 0 to the subdissector.)