A channel will be released in case of
* Errors via the clear_request callback...
* no more transactions and operations are going on.
This means that if we do something without a transaction
the channel might be closed down right away. The bug fix
will be to create a transaction/operation.
This is a big change to the way we use the subscriber
connection. From now on it is is dynamically allocated
and we will slowly move from a 1:1 lchan to conn to
having more than one lchan per connection.
This is the first commit, the subscr_con* methods will
move to gsm_data once the use_count is removed from the
connection, the freeing of the connection will also change.
The lowlevel BSC paging API is a simple wrapper around
the RSL command. The BTS will automatically repeat these
messages but if we end up with two MSC inputs we will
need to count these messages somewhere...
When submitting a DTAP message, the BSC API will attempt to
establish the RLL layer and then send the message or send an
SAPI n REJECT. This will be used by the SMS code.
The 08.08 API will interface with the internal BSC code and it is
the boundary between MSC and BSC. So nothing that calls the BSC
functionality should know about lchan or such.