Serving GPRS Support Node (SGSN). As such it implements the GPRS Mobility Management (GMM) and SM (Session Management).
The SGSN connects via the Gb-Interface to the BSS (like the [[osmo-pcu]] or an ip.access nanoBTS), and it connects via the GTP protocol
to a Gateway GPRS Support Node (GGSN) like [[OpenGGSN]].
[[OsmoSGSN]] is part of the openbsc git repository. In order to build it, you will need a libgtp installation from the
h2. Setup / Configuration
For more information regarding the setup + configuration, refer to [[OpenBSC_GPRS]]
h2. TODO list
* use the [[OsmoNITB]] HLR to identify (and possibly authenticate) subscribers
* secondary PDP contexts
* persistent storage of GMM and SM state
* recovery from GGSN outages
* SNDCP header and data compression
* use proper XID exchange and actually use the results to configure the LLC SAPIs
* GEA3 encryption
* SMS delivery via GPRS
* network-initiated PDP context activation