osmo-bsc/src
Vadim Yanitskiy a88fa1f12f RSL/BSSAP: fix: properly convert between RSL Link ID and DLCI
Data Link Connection Identifier (DLCI) is defined in 3GPP TS 48.006,
section 9.3.2, and coded as follows:

  .... .SSS - SAPI value used on the radio link;
  CC.. .... - control channel identification:
    00.. .... - indicates that the control channel is not further specified,
    10.. .... - represents the FACCH or the SDCCH,
    11.. .... - represents the SACCH,
    other values are reserved.

RSL Link Identifier is defined in 3GPP TS 3GPP TS 48.058,
section 9.3.2, and coded as follows:

  .... .SSS - SAPI value used on the radio link;
  ...P P... - priority for SAPI0 messages;
  CC.. .... - control channel identification:
    00.. .... - main signalling channel (FACCH or SDCCH),
    01.. .... - SACCH,
    other values are reserved.

As can be seen, CC bits in both DLCI and RSL Link Identifier
are coded differently.  Therefore, we cannot just assign
one identifier to another, we need to do conversion.

I noticed that osmo-bsc indicates DLCI '01000011'B for SMS
messages sent over SACCH/F (SAPI3), and this is wrong because
'01'B is reserved.  Let's fix this.

P.S. Interesting coincidence: section 9.3.2 in both documents.

Change-Id: If4d479a54cad467f53b49065c1c435a4471ac7d2
Related: Ica69ae95b47a67ba99ba9cc36629b6bd210d11e4
Related: OS#3716
2020-10-08 07:15:01 +00:00
..
ipaccess rename files acc_ramp.* -> acc.c* 2020-07-20 16:21:59 +02:00
osmo-bsc RSL/BSSAP: fix: properly convert between RSL Link ID and DLCI 2020-10-08 07:15:01 +00:00
utils rename files acc_ramp.* -> acc.c* 2020-07-20 16:21:59 +02:00
Makefile.am drop IMSI filter and libfilter completely 2020-05-27 01:56:06 +02:00