Wireshark · Ethereal-dev: Re: [Ethereal-dev] dealing with 2 dissectors on the same port

[Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx>]

Jeff,

SCTP tries first to find the ULP by looking at the Payload
Protocol Identifier. Only if that does not work the port is
used.

M2UA uses PPI = 2 and M2PA uses PPI = 5.

This means if you use the correct PPI in your M2UA, M2PA
implementation ethereal will find always the correct ULP.
Yo do not need to disable a protocol. By using this you
can also transport M2UA and M2PA over the same assoc and
ethereal will dissect it correctly.

If it is not working, please send me a short trace file
and I will see what is going wrong.

Best regards
Michael

On Thursday, June 20, 2002, at 05:35 PM, Jeff Morriss wrote:

> Hello list,
>
> I have some M2PA captures which Ethereal tries to dissect as M2UA (the 
> SCTP port for M2UA and M2PA are the same).
>
> So I try disabling M2UA thinking that then M2PA will be used.  But it's 
> not...
>
> Looking in 'dissector_try_port()' it basically tries the first 
> dissector it finds in the table and will return FALSE if that dissector 
> is disabled (so that other dissectors can have a chance).  But what if 
> there is another dissector in there (or is that possible?)?
>
> Is there any way for me to get this to work short of changing the M2UA 
> port on my builds (or removing it altogether)?  Am I just missing 
> something?
>
> Thanks,
> -Jeff
>
> -- Jeff Morriss
> Senior Support Engineer
> Ulticom, Inc.
> Helpdesk: +1-856-787-2765
> Fax: +1-856-222-9947
>
>
> _______________________________________________
> Ethereal-dev mailing list
> Ethereal-dev@xxxxxxxxxxxx
> http://www.ethereal.com/mailman/listinfo/ethereal-dev
Michael.Tuexen@xxxxxxxxxxxxxxxxx