Serving GPRS support
node (SGSN):

The
SGSN is a functional entity that provides packet data services. It forwards
incoming and outgoing internet protocol (IP) packets to the mobile stations
(MSs) within its service area.

The
SGSN provides the following functions:

• Routing and
       forwarding of data packets


• Encryption and
       authentication


• Session
       management


• Mobility
       management


• Logical link
       management


• Generation and
       output of call detail records (CDRs)