Ethereal-dev: Re: [Ethereal-dev] sample file for GSM frames

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From: Neil Piercy <Neil.Piercy@xxxxxxxxxxxx>
Date: Thu, 04 Aug 2005 11:10:01 +0100
Hi folks,

I haven't kept up with this thread, but if it is relevant, my company makes IP-connected GSM BTSs and BSCs, and certainly have traces of BSSMAP (including DTAP) carried over a fairly "standard" SCTP/M2UA/MTP3/SCCP to a signalling gateway (where it goes into a conventional SS7 stack over E1/T1), and also BSSMAP carried over a simpler (internal) SCCP/TCP.

If you need sample traces for testing etc, I might be able to provide some.

Regards,
Neil

LEGO wrote:

the only dtap-only traces I've found so far are text dumps generated
by a program attached to a mobile with a "debug" firmware. I haven't
yet seen any other types of dtap-only traces (I'll have a chat with a
friend of mine that actually tests the mobile phones, he'll ceratinly
know better than me)

dtap is used to have the mobile to "talk" to the MSC (to the SGSN
too?) and is normally encapsulated inside NBAP, RANAP, BSSAP in its
way to the Mobile or MSC.
On 8/3/05, Guy Harris <gharris@xxxxxxxxx> wrote:

LEGO wrote:


If the case is the second you should:
+  generate a pcap file containing the payload and use one of the user
DLTs (147->162).
      text2pcap -l 147 input.txt output.pcap

+ configure ethereal to decode as TCAP that DLT.
   preferences->protocols->DLT User [ABCD]
   DLT: the one choosen
   payload: gsm_dtap

Are DTAP traces sufficiently common that it'd be useful to add a
WTAP_ENCAP_GSM_DTAP - and possibly reserve a DLT_ value for it?  (I
don't know what binary trace formats from various GSM-tracing equipment
exist, or whether they're either documented or reverse-engineerable; if
any are, the ability to read them might be useful.)





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