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diff --git a/doc/manuals/chapters/overview.adoc b/doc/manuals/chapters/overview.adoc new file mode 100644 index 000000000..b6cc2e888 --- /dev/null +++ b/doc/manuals/chapters/overview.adoc @@ -0,0 +1,69 @@ +[[overview]] +== Overview + +This manual should help you getting started with OsmoBSC. It will cover +aspects of configuring and running the OsmoBSC. + +[[intro_overview]] +=== About OsmoBSC + +OsmoBSC is one particular version of the OpenBSC software suite. + +Unlike the highly integrated OmsoNITB, OsmoBSC impleents a more classic +GSM Base Station Controller with A-bis interface towards BTSs and A +interface towards a MSC. + + +=== Software Components + +OsmoBSC contains a variety of different software components, which +we'll quickly describe in this section. + +==== A-bis Implementation + +OsmoBSC implements the ETSI/3GPP specified A-bis interface, including +TS 08.56 (LAPD), TS 08.58 (RSL) and TS 12.21 (OML). In addition, it +supports a variety of vendor-specific extensions and dialects in order +to communicate with BTSs from Siemens, Nokia, Ericsson, ip.access and +sysmocom. + +For more information, see <<bts>> and <<bts-examples>>. + +==== A Implementation + +OsmoBSC implements a minimal sub-set of the GSM A interface as specified +in TS 08.08. + +Unlike classic A interface implementations for E1 interfacs, OsmoBSC +implements a variant of encapsulating the A interface over IP. To do +so, the SCCP messages are wrapped in an IPA multiplex and then +communicated over TCP. The audio channels are mapped to RTP streams. + +This protcol stacking is sometimes called "SCCPlite". + +For more information, see <<alink>>. + + +==== BSC Implementation + +The BSC implementation covers the classic functionality of a GSM Base +Station Controller, i.e. + +* configuring and bringing up BTSs with their TRXs and TSs +* implementing the A-bis interface / protocols for signalling and actual + voice data (TRAU frames). +* processing measurement results from the mobile stations in dedicated + mode, performing hand-over decision and execution. +* Terminating the TS 04.08 RR (Radio Resource) sub-layer from the MS. + +For more information, see <<net>>, <<bts>> and <<bts-examples>>. + + +==== TRAU mapper / E1 sub-channel muxer + +Unlike classic GSM networks, OsmoBSC does not perform any transcoding. +Rather, a compatible codec is selected for both legs of a call, and +codec frames are passed through transparently. In order to achieve this +with E1 based BTS, OsmoBSC contains a E1 sub-channel de- and +re-multiplexer as well as a TRAU mapper that can map uplink to downlink +frames and vice versa. |