Testing protocol stack with OsmocomBB (cheap way)

Drasko DRASKOVIC drasko.draskovic at gmail.com
Sun May 29 22:34:08 UTC 2011


Hi all,
going through the documentation, I am trying to figure out what would
be the best way to have whole protocol stack communication with
OsmocomBB.

Now, I understand that osmocon can be used to load layer1 into phones
RAM, so that this code turns on Calypso and communicate with DSP with
AT commands. Then osmocon gets messages from layer1 via RS232 and can
distribute them to the mobile application, which sends them to layer23
for further processing or via GSM tap to Wireshark or outputs them on
stdout.

What I am most interested in how do we insert pacgaes on the other
side of the stack, i.e. via telephone air interface (packets that will
traverse through Rita, Iota, Calypso down to stdout of host). From
what I understand we need some kind of BTS, and I can see that GNU
Radio is used for this purpose. But for this, as I understand USPRP
(http://en.wikipedia.org/wiki/Universal_Software_Radio_Peripheral)
FPGA motherboard with both RX and TX doughterboards is needed, which
can go up to 1k eur (too expensive for a hobbist).

I was wondering so, what is the best and the cheapest way to inject
packets at the protocol stack on the phone and analyze some packet
flow later with Wireshark - i.e. to get some usage of the OsmocomBB
and to see how it works. At this point I can only run Hello World
application, or "mobile" app without any usage (or I do not know how
to use it). What would be the best way to start playing around without
spending too much money.

Speaking of this, what would be the price of the cheapest existing
packet generator that can transmit them via Um (i.e. what is the price
of the cheapest BTS)?
Is there some open source FPGA that can be used for this purpose?

Thanks for your explanations and best regards,
Drasko




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