|
Serving GPRS
Support Node (SGSN)
For the upgrading of the GSM network to cope with GPRS the SGSN
is the primary component, and the SGSN is a new component in
GSM. The SGSN forwards all incoming and outgoing IP packets addressed
to/from an MS that is attached within the SGSN service area.
The SGSN provides packet routing and transfer to and from the
SGSN service area. SGSN serves all GPRS subscribers that are
physically located within the geographical SGSN service area.
A GPRS subscriber may be served by any SGSN in the network, all
depending on the geographical location. The traffic is routed
from the SGSN to the BSC, via the BTS to the MS. Also the SGSN
provides:
- Ciphering and Authentication
- Session Management
- Mobility Management
- Logical Link Management toward the MS
- Connecting to HLR, MSC, BSC, GGSN and other nodes
- Output of billing data |
|
Gateway GPRS
Support Node (GGSN)
As with the SGSN the GGSN is a new primary component in the GSM
network when using GPRS. The GGSN provides the following functions:
The interface toward the external IP packet networks, the GGSN
therefore contains access functionality that interfaces with
an external ISP, functions such as, routers and RADIUS (Remote
Dial-In User Services) servers. From and external IP networks
point of view the GGSN is acting as a router for the IP addresses
of all subscribers served by the GPRS network. So the GGSN exchanges
routing information with the external network.
GPRS session management, communication setup toward external
network.
Functionality for associating the subscribers with the right
SGSN.
Output billing data, the GGSN collects information for each MS,
related to the external data network usage. Both the GGSN and
the SGSN collect billing information on the usage of the GPRS
network resources. |
|
Authentication
Center (AUC)
The AUC is a GSM component that provide triplets to the authentication
and ciphering process used within GSM, the authentication for
GPRS is the same as for GSM users, the only change is in the
security for GPRS is related to ciphering, however this change
does not require any change in software or hardware. |