COBHAM Sailor 250 FleetBroadband, Training Manual, Page: 21 / 270

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SAILOR FleetBroadBand
Training Manual
1
SMSC (Short Messaging Service Centre):
Short Messaging Service Centre- requires an smsc number which
instructs all sms’ from your mobile to be sent to this centre. This
then forwards the message to the destination number.
FRINs (Forced Routing Inmarsat Management System).
1.5.3 SGSN
SGSN (Servicing GPRS Support Node):
The SGSN registers a user onto the network, checks with HLR to
verify that the user is a valid user/subscriber and creates billing
files (CDRs).
The SGSN keeps track of the location of the individual MS’s and
performs security functions and access control.
A SGSN is responsible for the delivery of data packets to and from
the mobile stations within its geographical service area.
The tasks of the SGSN include packet routing and transfer, mobility
management (attach/detach and location management), logical
link management, and authentication and charging functions.
GPRS security functionality is equivalent to the existing GSM
security.
The SGSN performs authentication and cipher setting procedures
based on the same algorithms, keys, and criteria as in existing
GSM.
GPRS uses a ciphering algorithm optimised for packet data
transmission.
1.5.4 GGSN
GGSN (Gateway GPRS Support Node):
The GGSN provides interaction with external packet-switched
networks, and is connected with SGSN’s via an IP-based GPRS
backbone network.
The GGSN acts as an interface between the GPRS backbone
network and the external packet data networks. It converts the
GPRS packets coming from the SGSN into the appropriate PDP
(Packet Data Protocol) format, e.g. IP, and sends them out on the
corresponding packet data network. In the other direction, PDP
addresses of incoming data packets are converted to the GSM
address of the destination user. The re-addressed packets are
sent to the responsible SGSN. For this purpose, the GGSN stores
the current SGSN address of their profile in its location register.
The GGSN also performs authentication and charging functions.
The GGSN is uniquely identified by an APN (Access Point
Name).
It also creates billing files (CDR’s).
Figure 1-21
Figure 1-22