rewrite README

Change-Id: If78b74494a00ad230aec94e03b2fe4e905473897

README

@@ -1,39 +1,17 @@
-About OpenBSC
-=============
+About OsmoSGSN
+==============
 
-OpenBSC started as a minimalistic all-in-one implementation of the GSM Network,
-with particular emphasis on the functionality typically provided by the BSC,
-MSC, HLR, VLR and SMSC.  Today it is a growing suite of libraries and programs,
-implementing protocol stacks and functional elements, including
+OsmoSGSN originated from the OpenBSC project, as a separate program within
+openbsc.git. In 2017, OpenBSC was split in separate repositories, and hence
+OsmoSGSN was given its own separate git repository.
 
- * OsmoBSC - a pure GSM BSC, speaking Abis/IP to the BTS and A/IP to the MSC
- * OsmoBSC-MGCP - MGCP helper to the OsmoBSC software
- * OsmoNITB - a BSC+MSC+VLR+HLR+SMSC "Network in the box".
- * OsmoMSC - a voice CN with A/IP and IuCS/IP towards the BSC and/or HNB-GW
- * OsmoSGSN - a GPRS SGSN with Gb/IP and IuPS/IP towards the PCU and/or HNB-GW
- * Osmo-GbProxy - a Proxy to aggregate many Gb links as one Gb link to the SGSN
- * OsmoBSCNAT - a gateway aggregating many A links as one A link to the MSC
- * OsmoGTPHUB - a hub aggregating many GTP links (between SGSN and GGSN)
- * ipaccess-utils - some tools to discover + configure ip.access nanoBTS
- * bs11_config - a tool to configure the Siemens BS-11 microBTS
+OsmoSGSN exposes
+- GSUP towards OsmoHLR (or a MAP proxy);
+- GTP towards a GGSN (e.g. OsmoGGSN);
+- Gb towards a BSS (e.g. OsmoPCU);
+- IuPS towards an RNC or HNB-GW (e.g. OsmoHNBGW) for 3G data;
+- The Osmocom typical telnet VTY and CTRL interfaces.
 
-Various interfaces towards the BTS are supported, among which are:
-
- * Classic A-bis over E1 using a mISDN based E1 interface. In other
-   words, you can connect existing GSM Base Transceiver Station (BTS)
-   through E1 to OpenBSC.  So far, we have made it work with the Siemens BS-11,
-   various Ericsson RBS2xxx BTS models and the Nokia MetroSite.
-
- * A-bis over IP as used by the ip.access nanoBTS product family as well as
-   the Open Source OsmoBTS software (by the same authors as OpenBSC).  OsmoBTS
-   in turn supports various transceiver hardware, including the sysmoBTS
-   product family, as well as SDR transceivers supported by OsmoTRX, such as
-   the UmTRX or USRP boardss.
-
- * IuCS and IuPS over IP towards an HNB-GW (see osmo-iuh) for UMTS (3G)
-   voice and data links.
-
-Find OpenBSC online at
-http://openbsc.osmocom.org/
-
-	Harald Welte <laforge@gnumonks.org>
+Find OsmoSGSN issue tracker and wiki online at
+https://osmocom.org/projects/osmosgsn
+https://osmocom.org/projects/osmosgsn/wiki