layer23 bursts - strategy for filtering IA's for tmsi based on downlink traffic only?
mad at auth.se
Wed Feb 23 14:34:09 UTC 2011
On Wed, 23 Feb 2011 09:53:34 +0000 (GMT), MATTHEW EVANS wrote:
> I am running some tests/experiments with the burst_ind branch. I want
> to be able
> to only follow the immediate assignments for my TMSI as it is
> difficult to
> verify that the bursts are indeed my traffic. However, I suspect this
> is not
> possible using only downlink traffic as without the channel request
> from the MS
> I cannot match the resulting IA? I would need to capture uplink too?
Even if you would capture the uplink on the RACH you would not be able
distinguish your phones request using your tmsi because IAs refer to
their Random Reference (04.08, 9.1.8). Only if you knew this reference
follow only your phones DCHs. The first time a tmsi/imsi may be sent is
already established DCH.
Of course you could still implement something that only if a RACH
received on uplink the IA is followed, so you could be sure to follow
requests from phones in your vicinity.
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