GSM - Architecture, Protocols and Services, Third Edition

Appendix A. Data communication and networking

For the third edition of this book, we have moved this chapter on classical GSM data services from the main body to an appendix because we believe that with the advent of GSM Phase 2+ services, such as HSCSD and most prominently GPRS, the classical GSM data services are of minor importance and hardly used anymore. However, we did not want to remove them completely from the book and rather present them in this appendix for completeness.

Reference configuration

GSM was conceived in accordance with the guidelines of ISDN. Therefore, a reference configuration is also defined for GSM systems, similar to that used in ISDN systems. Using the reference configuration, one can get an impression of the range of services and the kinds of interfaces to be provided by MSs. Furthermore, the reference configuration indicates at which interface which protocols or functions terminate and where adaptation functions may have to be provided.

The GSM reference configuration comprises the functional blocks of a MS (Figure A.1) at the user-network interface Um. The mobile equipment is subdivided into a Mobile Termination (MT) and various combinations of Terminal Adapter (TA) and TE, depending on the kind of service access and interfaces offered to the subscriber.

At the interface to the mobile network, the air interface Um, MT units are defined. An integrated mobile speech or data terminal is represented only by an MT0. The MT1 unit goes one step further and offers ...