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ETSI
ETSI EN 301 344 V7.1.1 (2000-01)16(GSM 03.60 version 7.1.1 Release 1998)
User network access may occur from either the mobile side or the fixed side of the GPRS network. The fixed network
interface may support multiple access protocols to external data networks, for example X.25 or IP. The set of access
protocols to be supported is determined by the PLMN operator.
Individual PLMN administrations may require specific access-control procedures in order to limit the set of users
permitted to access the network, or to restrict the capabilities of individual users, for example by limiting the type of
service available to an individual subscriber. Such access control procedures are beyond the scope of the GPRS
specifications.
In addition to the standard PTP data transfer, GPRS may support anonymous access to the network. The service allows
an MS to exchange data packets with a predefined host that can be addressed by the supported interworking protocols.
Only a limited number of destination PDP addresses can be used within this service. IMSI or IMEI shall not be used
when accessing the network thus guaranteeing a high level of anonymity. Therefore, no authentication and ciphering
functionalities are foreseen for anonymous access.
5.3.1.1 Registration Function
Registration is the means by which a user's Mobile Id is associated with the user's packet data protocol(s) and
address(es) within the PLMN, and with the user's access point(s) to the external PDP network. The association can be
static, i.e., stored in an HLR, or dynamic, i.e., allocated on a per need basis.
5.3.1.2 Authentication and Authorisation Function
This function performs the identification and authentication of the service requester, and the validation of the service
request type to ensure that the user is authorised to use the particular network services. The authentication function is
performed in association with the Mobility Management functions.
5.3.1.3 Admission Control Function
The purpose of admission control is to calculate which network resources are required to provide the quality of service
(QoS) requested, determine if those resources are available, and then reserve those resources. Admission control is
performed in association with the Radio Resource Management functions in order to estimate the radio resource
requirements within each cell.
5.3.1.4 Message Screening Function
A screening function concerned with filtering out unauthorised or unsolicited messages is required. This should be
supported through packet filtering functions. Network-controlled screening is supported in the first phase of GPRS.
Subscription-controlled and user-controlled screening may be provided in a later phase.
5.3.1.5 Packet Terminal Adaptation Function
This function adapts data packets received / transmitted from / to terminal equipment to a form suitable for transmission
across the GPRS network.
5.3.1.6 Charging Data Collection Function
This function collects data necessary to support subscription and/or traffic fees.
5.3.2 Packet Routeing and Transfer Functions
A route is an ordered list of nodes used for the transfer of messages within and between the PLMN(s). Each route
consists of the originating node, zero or more relay nodes and the destination node. Routeing is the process of
determining and using, in accordance with a set of rules, the route for transmission of a message within and between the
PLMN(s).
5.3.2.1 Relay Function
The relay function is the means by which a node forwards data received from one node to the next node in the route.