An Experiment of Dependability and Performance of GSM Access to Fixed Data Network

Heimo Laamanen: An Experiment of Dependability and Performance of GSM Access to Fixed Data Network. Report C-1995-41, Department of Computer Science, University of Helsinki, September 1995. 21 pages. <http://www.cs.helsinki.fi/TR/C-1995/41>

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Abstract

Recent developments in mobile computing have created new possibilities for mobile offices. Integration of wireline and wireless networking lays a new foundation for services available in traditional fixed computer networks almost everywhere. However, integration of a wireless wide area network (WWAN) and a fixed data network raises several technical questions including dependability and performance. An experiment was carried out at Digital Equipment Corporation Oy (Finland). The goals of this experiment were to examine the dependability and the performance of GSM data communications in everyday working circumstances and to explore users' opinions about GSM data communications. Employees had wireless data access to Digital's fixed data network. The participants of the experiment used the same applications out of the office as they nor-mally used at the office. The participants' opinions were obtained using questionnaires. The performance was measured with software tools in two different environments. Three basic operations were measured: connection establishment, exchange of request-reply messages, and bulk data transfer. The results of the experiment demonstrate that the participants were satisfied with GSM data communications, regardless of the unreliability and the occasional unavailability. The results indicate that the technology of the GSM data service is mature enough to be used in specific, well-defined services of computer networks. However, the reliability and the availability of the GSM data service are not satisfactory for today's client-server applications. A disconnection of the GSM connection is common in everyday working circumstances. The response time in an interactive operation is sufficient to end-users when the amount of data is small. The maximum sustainable transfer rate is about 900 octets per seconds. The transfer rate of the uplink is normally less and more unsteady than the transfer rate of the downlink.

Index Terms

Categories and Subject Descriptors:
C.2.1, C.4

General Terms:

Additional Key Words and Phrases: wireless data, mobility, mobile workstations, mobile office, GSM, TCP/IP