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Underground Information System

Term Paper 2008 22 Pages

Computer Science - Internet, New Technologies

Excerpt

Middlesex University London CCM3061 Mini Project

The following report will givo an introduction to WAP, its programming model, tho architecture, services and peculiarities in comparison to tho World Wide Web, WAP; s features are evaluated and especially security, usability, performance and quality-of-service issues are reviewed. Based upon the WAP introduction and its major findings, an analysis and design has been made for a concrete WAP applieation, This applieation serves as an information system for transportation systems and allows users to be kept up-to-date on actual maintenanee, breakdowns and malfunctions in a transportation network, Functional and non-funetional requirements, use-eases, aetivities, the database seheme, deployment and realization requirements of the proposed project will be diseussed, Finally, the report will conclude with an evaluation of the project and a discussion about possible extensions and further work.

1 Introduction

In tho last few yoars, tho Internet has become an important part of everyday lifo. Today, people socialize, bargain, request information and share documents through this network, which is counting a vast number of Computers. The services were firstly only available for desktop Computers, but major Companies soon realized that an extension for wireless devices and mobile phones would result in additional benefits, as the technology was advanced enough to display a considerable amount of data on mobile devices. Therefore, WAP was introduced to bring the Internet to the wireless world and enabled users to use the Internet and its services on the way, During the last years, the number of mobile-Internet-users increased, the equipment improved (which allowed the display of more complex pages), and new services were popping up every day.

First of all, this report will deal with the basis of WAP, which allows mobile devices to use the Internet, and will discuss issues related to security, usability and performance. The evaluation of WAPs architecture, its functionality and components is primarily based upon the official architecture documentation |Ltd01| published by the Open Mobile Alliance |Ope|, an official white paper discussing changes from WAP 1.x to WAP 2.x |Ltd02| and a formal report by Ericsson on WAP 2.0 |Pet01|. Secondly, the analysis and design of a WAP applieation will be introduced, which takes all the Undings from the previous chapter into account. The analysis and design proeedure is based on the IBM Rational Software Development Proeess and implementation decisions and features rest upon the specification of the XHTML Mobile Profile |Ltd07|, a tutorial on the XHTML Mobile profile |Dev|, a review on WAP security issues |Tha00| and a framework of an existing svstem |ABAA05|.

2 WAP Review

WAP is a teehnology, whieh was introdueed to bring the Internet to the wireless world. Wireless deviees are more eonstrained than desktop Computers - they have less powerful CPUs, less memory, restrieted power eonsumption, smaller displays and a limited input deviee |Ltd01|, What is more, wireless data networks allow for less bandwidth, have more lateney, less eonneetion stability and a less predietable availability |Ltd01|, WAP was designed to take all these eonstraints into aeeount to allow wireless deviees to aeeess the Internets new and exeiting information serviees, It implements its own seeurity model, allows for simple development through the XHTML Mobile Profile |Ltd07|, is widely aeeepted by major players and is standard-independent |Har02|, This seetion will deal with all the eonstraints and peeuliarities of WAP applieations and their impaet on the WAP-projeet,

2.1 WAP Programming Model

The WAP programming model is elosely related to the Web programming model, It extends this model by adding telephony Support and WAP push, whieh allows servers to eontaet elients, |Ltd02| Figure 1 depiets this model, whieh enables WAP deviees to reeeive eontent through the pull and push paradigm, This model may be extended by a WAP proxy, whieh optimizes the eommunieation proeess and is neeessary for the push funetionalitv.

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Figure 1: WAP programming model |Ltd02|

The WAP architecture relies on existing Standards, which have evolved in the World Wide Web, These Standards have been adopted and enhancements have been made to improve the user experience on WAP devices and to allow for WAP-specific functional-ity, i.e. WAP Push and Telephony Support |Pet01|. The architecture consists of four components: the applieation framework, the protocol framework, security services and the Service diseovery |Pet01|. Figure 2 outlines the layered design of the WAP protocol stack.

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Figure 2: WAP stack architecture |Ltd01|

The applieation framework is based on a combination of World Wide Web and Mobile Telephony technologies and provides browsing, calenders, user-agent profiles, multimedia messaging and push services |Pet01|. The protocol framework is divided into Session Services, Transfer Services, Transport Services and Bearer Networks and will be ex-plained in sub section 2,2,2, Security is an integral part of the WAP architecture and will be attended to in sub-chapter 2,2,3, Service diseovery will not be examined in detail - in short, it ean locate external functions on the device, on a network or look up a Service through a directory |Ltd01|,

WAP 2.0 supports Internet protoeols, Figure 3 presents a eonerete example eonfiguration: a WAP HTTP proxy with profiled TCP and HTTP. Although WAP speeifies minor modifieations for some of these layers, they are fully eompatible with common Internet protoeols. The transmission must pass a proxy, whieh may only serve as a gateway to eonneet the wireless world with the Internet. The protocol layer TLS provides security funetions, A reliable eonneetion is realized by TCP, whieh allows for packet retransmissions by dass 2 transaetions.

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Figure 3: WAP protocol stack |Ltd02|

2.2.2 Protocol Framework

All protoeols and serviees operate over a variety of bearer serviees ineluding the mobile radio bearers USMS, FLEX, USSD and GUTS, as well as IP versions four and six. The following WAP 2.0 serviees, whieh are important for an effieient data flow are subsumed from |Ltd01|, Transport serviees allow for the transportation of unstruetured data aeross multiple bearer networks and inelude datagrams (without relianee, UDP) and eonneetions (three well-defined phases: eonneetion establishment, two-way reliable data transfer and eonneetion release). Transfer serviees enable the struetured transfer of data between network elements and allow for hypermedia, Streaming and message transfer. The session serviees enable the establishment of a shared state between network elements and provide eapability negotiation, Push-OTA, Syne and eookies.

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Details

Pages
22
Year
2008
ISBN (eBook)
9783656099468
File size
13.3 MB
Language
English
Catalog Number
v185045
Institution / College
Middlesex University in London
Grade
1/20 (Bestnote)
Tags
underground information system

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Title: Underground Information System