Wireshark · Ethereal-dev: Re: [Ethereal-dev] ISUP patch

[Jeff Morriss <morriss@xxxxxxxxx>]

Guy Harris wrote:
> On Fri, Aug 15, 2003 at 11:31:37AM -0700, Michael Lum wrote:
>
> > I believe the ISUP dissector has a bug when decoding the
> > optional parameter pointer.
>
>
> So what is the added check doing?  It looks as if it's checking whether
> the optional parameter pointer is present in the packet.

It depends.  I think I read that this was an ANSI RLC.  The ISUP 
dissector as it stands now was written for ITU ISUP.  (It appears to 
"mostly work" for ANSI, though.)

In ITU ISUP, the RLC message can have optional parameters (and thus a 
pointer to optional).

In ANSI ISUP, the RLC message does not have any optional parameters (and 
thus no pointer to optional).

(Porting the ISUP dissector to also do ANSI ISUP has been on my hit-list 
for a very long time...)