The existing gsm_04_08.c implementation is mixing BSC and MSC
behavior. Move some simple parsing and generation functions over
to gsm_04_08_utils.c to allow a different MSC to define the policy.
this enables the caller to detect if the paging request was rejected
by the paging layer, especially in case it is already paging this very
subscriber.
In the case of SMS / 04.11, we used to have a memory leak of struct gsm_sms's,
since we would only free them from the paging succeeded/expired callbacks.
SMS related messages are all sent over SAPI=3. But in addition
to that, we also need to send it over the correct link identifier,
i.e. SACCH or main signalling channel
The channel allocator can be set in ascending or descending order.
Ascnending means we first try to allocate channels on TRX0, then TRX1, etc.
Descending means we first try to allocate cahnnels on TRXn, then n-1 down to 0.
SM's need to be transferred over their own RLL connection on SAPI3, rather than
the default SAPI0 connection that we're using for signalling like 04.08
RR/MM/CC.
This is not that much of a problem in the case of SMS SUBMIT from the MS to
the netwrok. In that case, the MS will start its primary RLL connection
with SAPI3, and we can just respond with SAPI3.
However, in the case of SMS DELIVER to a MS, we first page the MS, it then
establishes SAPI0. We then need to explicitly request the establishment of
a SAPI3 RLL connection, before we can send CP-DATA with our RP-DATA and DELIVER
RPDU
Now that we have the bsc_rll.c code, we can actually wait for a paging
response, and from the paging response request the establishment of the SAPI3
connection. We will be called back once that connection is open and can
successively start transmission of the SM.
A caller can call rll_establish(lchan, link_id) and a callback to the GSM RLL
code. He will get called back if the RLL link is established or receives some
error message, or the establishment times out.
We need this for proper SMS implementation, where we need to restablish a SAPI3
RLL link before transmitting the actual CP-DATA messages.
we now have the full path from the MS into the database (SUBMIT), as well as
back from the database to the MS (DELIVER). The database gets correctly
updated once a SMS has been successfully delivered.
What's still missing is the periodic scan over all undelivered messages,
trying to deliver them to the respective MS. So far, you have to manually
trigger this on the telnet interface with 'sms send pending 1'
So far, we immediately disable the RF channel without following a proper
RLL RELEASE procedure. This patch changes this.
If we locally terminate the connection, the channel allocator now triggers a
RLL RELEASE REQuest, which is responsed by the MS with a RLL RELEASE CONFirm,
based on which we send the RF CHANnel RELease to the BTS.
If the MS terminates the connection, we receive a RLL RELEASE INDication,
based on which we trigger RF CHANnel RELease to the BTS.
This helps us to detect the frequency error of BS-11 if it is located
next to the nanoBTS 900.
If 'ipaccess-config -l' is called, it will produce a report like
<0020> ipaccess-config.c:85 TEST REPORT: test_no=0x42 test_res=0
<0020> ipaccess-config.c:108 ==> ARFCN 220, Frequency Error 22
<0020> ipaccess-config.c:108 ==> ARFCN 1, Frequency Error -37
<0020> ipaccess-config.c:108 ==> ARFCN 10, Frequency Error 0
<0020> ipaccess-config.c:108 ==> ARFCN 20, Frequency Error 11
<0020> ipaccess-config.c:108 ==> ARFCN 53, Frequency Error 5
<0020> ipaccess-config.c:108 ==> ARFCN 63, Frequency Error -4
<0020> ipaccess-config.c:108 ==> ARFCN 84, Frequency Error 11
<0020> ipaccess-config.c:108 ==> ARFCN 101, Frequency Error 0
<0020> ipaccess-config.c:108 ==> ARFCN 123, Frequency Error -52
where in this case the ARFCN 123 is the BS-11 with a frequency error
larger than all the other (regular) BTS in the vicinity.
Holger Hans Peter Freyther
Harald Welte