Some more thoughts on that old topic:
A custom protocol seems to make more and more sense. Neither original
RSL nor 08.08 seem to be a close match.
Some more specification of the original protocol idea:
On Wed, Apr 14, 2010 at 11:48:22PM +0200, Harald Welte wrote:
* ESTABLISH REQUEST -- app requests a channel be
established to MS (by IMSI)
Parameters:
* mobile identity (tmsi/imsi) (can re-use 04.08 mobile identity IE)
* channel type (sdcch/tch) (can reuse RSL information element)
* which parts of the protocol shall openbsc handle (RR/MM/CC)
* unique reference identifying this 'call/radio channel'
* ESTABLISH CONFIRM -- network confirms a channel has
been established
(confirmation that the radio channel has been established)
Parameters:
* unique reference identifying this call/radio channel
* exact arfcn/timeslot/sub-slot that was established
(can be RSL or 04.08 channel description)
* ESTABLISH INDICATION -- network tells app connection
was made by MS
(confirmation that a LAPDm connection was established)
Parameters:
* unique reference identifying this call/radio channel
* SAPI (RSL Link ID)
* [UNIT] DATA REQUEST -- app requests data to be sent
to MS
* [UNIT] DATA INDICATION -- network indicates data was received from MS
Parameters:
* unique reference identifying this call/radio channel
* SAPI (RSL Link ID)
* ERROR INDICATION -- network tells app something went
wrong
Parameters:
* unique reference identifying this call/radio channel
* error code / reason
* RELEASE REQUEST -- app asks network to release
channel
Parameters:
* unique reference identifying this call/radio channel
* RELEASE CONFIRM -- net tells app that channel was
released (as rqd)
Parameters:
* unique reference identifying this call/radio channel
* RELEASE INDICATION -- net tells app that channel was
released (by MS)
Parameters:
* unique reference identifying this call/radio channel
--
- Harald Welte <laforge(a)gnumonks.org>
http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)