Wireshark · Ethereal-dev: [Ethereal-dev] sample file for GSM frames

[Francisco.Cotrina@xxxxxx]

Hi
I am trying to analyse some GSM layer-2
frames that I extracted from my mobile phone.
The problem is that they don't have
the right header.
If I understand correctly, Ethereal
needs the frame to be inside TCP-IP encapsulation, probably also inside
something called MCU2 or similar.
But this doesn't apply to GSM, so I would need someone to embed my GSM
inside a frame that Ethereal can understand.
I suppose the developpers for the gsm_map
dissector have such examples, so if you can send me an example file, it
will be perfect for me.

Thanks
Francisco

for example, this is one of my frames:

25 06 21 00 05 f4 64 11 77 9e 2b 2b
2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 

25  001001--  Pseudo length
: 9 
    ------01  Flag
06  0-------  direction from
     : originating site
    -000----  TransactionID
      : 0
    ----0110  Protocol
Discrim.   : radio resource management messages

21  00100001  MESSAGE TYPE
       : PAGING REQUEST TYPE 1 

00  ----00--  spare bits  
       : 0
    ------00  Page Mode
          : Normal paging
    --00----  Channel
Needed      : (first) Any Channel
    00------  Channel
Needed      : (second) Any Channel

: Mobile Identity 1
05  00000101  length of Mob.ident.:
5                 
f4  1111----  Identity Digit
1    : hex value = f, if  TMSI/P-TMSI
    ----0---  No. of
ID digits    : even 
    -----100  Type of
identity    : TMSI/P-TMSI
64  01100100  Identity Digit
2,3  : take hex value
11  00010001  Identity Digit
4,5  : take hex value            
      
77  01110111  Identity Digit
6,7  : take hex value            
             
9e  10011110  Identity Digit
8,9  : take hex value