1 / 24

INF 245 Mobile Applications Mobile thin clients a.k.a. Wireless Web

INF 245 Mobile Applications Mobile thin clients a.k.a. Wireless Web. H 2007 Ola Bø. (2004) wap trafic has multiplied. wap was launched in 1999, but never took off. A major fiasco.

calista-kennedy
Download Presentation

INF 245 Mobile Applications Mobile thin clients a.k.a. Wireless Web

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. INF 245 Mobile ApplicationsMobile thin clients a.k.a. Wireless Web H 2007 Ola Bø Molde University College INF 245 Fall 2007 OBø

  2. (2004) wap trafic has multiplied. wap was launched in 1999, but never took off. A major fiasco. Now starting to take off: browsing, reading news. Young users. Use tripled in a year. 10% of the 300 000 monthly users use the Wap Portal. GPRS a major factor explaining this development. Price differences Molde University College INF 245 Fall 2007 OBø

  3. dn.no3.9.2004 4 times more wap users from 2002Q4 to 2004Q2 1600 000 possible users 600 000 real users Molde University College INF 245 Fall 2007 OBø

  4. dn.no 28.5.2004 Nokia Users prefer using their phone for browsing Transition from WAP to HTML! Molde University College INF 245 Fall 2007 OBø

  5. Thin clients/Wireless Web – Introduction • The web is a huge success • Simple access to an enormous range of content and possibilities • We are still in the initial phase • The technology implies a division of work • A fairly simple (thin) client that can present HTML encoded content • A server doing most of the job • Composing and coding content from heterogeneous sources • Handle input from the user • Thin clients are appropriate for mobile devices with limited resources • But the screen is smaller – Micro Browser • >50% of the global installed base of handsets has a micro browser installed (Nokia 2004) • Ca 75 % of the GPRS traffic is mobile browsing (Nokia 2004) Molde University College INF 245 Fall 2007 OBø

  6. Wireless WWW – Architecture – An outline • Thin clients are doing the presentation – the challenge is a small screen • Middle tier transforms data from databases into HTML and processes input from the users • The Back end System (data base layer) Contains the data the mobile user wants access to. May be stored in relational databases, email-servers or as XML-content for instance RSS Molde University College INF 245 Fall 2007 OBø

  7. The Client OpenWave RIM • Less functionality than on desktop- or portable computers because of weaker computing power, smaller screen and limited bandwidth • More difficult to make good user interfaces supporting both navigation and display of interesting content. Important for the user reach his goal quickly. • Heterogeneity both in screen browser and markup language makes multiple variants of the pages necessary • The browser takes care of communication, so the developer does not need to handle communication protocols PALM WebClipping Pocket IE Opera browser on Nokia series 60 Molde University College INF 245 Fall 2007 OBø

  8. Middleware • Usually middleware is specially constructed for mobile applications. The middleware is run on application servers • Application servers • Handles complexity in serving a number of users integrating with databases and enterprise systems. Permits the developer to focus on developing modules containing business logic • Standardized • J2EE standard (JSP, Servlets, EJB) • Middleware for wireless applications are mainly built on J2EE standardization. • An alternative: .NET Molde University College INF 245 Fall 2007 OBø

  9. Middleware II • Middleware frameworks for mobile web can be bought • Solve most problems inherent i developing for the mobile web • Recognition of the device, screen size, browser and language • Content transformation • Session administration • Integration with enterprise databases and systems • Learning threshold can be overcome using development tools Molde University College INF 245 Fall 2007 OBø

  10. Mobile web applications – Common structure Application server Handles traffic arriving over HTTP, components, threading and pooling and integration with enterprise systems FrameWork for Mobile MiddlewareTranslates content to different devices custom made component custom made component Molde University College INF 245 Fall 2007 OBø

  11. J2EE Application Server • Standard platform for enterprise applications • Base technology: Java J2SE • Component model: EJB (Enterprise Java Beans) • Web technology JSP, Servlet, JSF (Java Server Faces) • Integration • Relational databases JDBC, • Catalog Services JNDI, • Existing software CORBA, JMS, JCA, JNI • XML JAXP, SOAP ... • J2EE is specified in JCP • Cooperation about specification, competition about implementation and hardware. Molde University College INF 245 Fall 2007 OBø

  12. Microsoft .NET • A comprehensive set of products for enterprise applications • Base technology: C# MSIL CLR • Web technology: ASP and XML web services • Component technology: COM -> COM+ ->.NET managed components • Integration: • ODBC for RDB -> OLEDB -> ADO -> ADO.NET for several types of data sources • Possible to write custom integration components • XML, SOAP • .NET is specified and sourced by one supplier- Microsoft • That may be an advantage • Why? • That can also be a disadvantage • Why? Molde University College INF 245 Fall 2007 OBø

  13. Processing of a wireless WWW request • Establish a wireless session • Send a request • May be binary coded • Translate the request • Safety problem (WAP-gap) • Receive request • ASP, JSF, JSP, Servlet, • Identify the client • What can we send to the client • Process request • Retrieve requested information • Adapt markup to client • Return content • Possibly recode in gateway • Application server may be placed with network operator • Gateway may be placed with enterprise to stop wap-gap • Gateway may be eliminated if http is used end to end. Molde University College INF 245 Fall 2007 OBø

  14. Convergence in standarisation, mark up and protocols Special standards for mobile terminals +300 companies +Location Interop Forum+SyncML Initiative+MMS Interop Group+Wireless Village2002 +Motorola, Nokia, Ericsson OpenWave HDML WAP ForumWAP 1.0WML1998 Not tcp/ip,but special protocols optimized for wireless slow connections An augmenting number of devices support TCP/IPHigher bandwidth Open Mobile AllianceWAP2WML2 =XHTML MPWP-HTTP, WP-TCP, WP-TLSCC/PP – UAPROF CSS DoCoMocHTML tcp/ip- og http- compatible but optimized for wireless slow connections Backwards compatible with WAP 1.0 W3CXHTMLBasic2000 Simplification:frames W3CHTML4.01997 W3CXHTML Added CSS+WML1elements WWW standards IETF – Ordinary Molde University College INF 245 Fall 2007 OBø

  15. Similar to http and web Pull: Client sends request for content But: Push and control over telephony is possible Gateway aka. WAP-proxy Compulsory in wap 1.0 Translates request from WAP to HTTP Compresses outgoing content Permits using standard HTTP servers to deliver content Implements push-functionality WAP 2.0 can work without proxy but a proxy may give advantages Optimized communication Support for services like push, localization and encryption The WAP model Molde University College INF 245 Fall 2007 OBø

  16. Wireless Application Environment Specifies the interface for micro browser – WML and WMLScript Special data format WBMP, vCard, vCalendar From WAP2 WML2=XHTML MP built upon XHTML-basic Support for Style sheets Backwards compatible with WML1 WAP protocol stack WAP components Molde University College INF 245 Fall 2007 OBø

  17. Molde University College INF 245 Fall 2007 OBø

  18. Convergence with standard WWW Markup language WML2=XHML Mobile Profile = XHTML Basic Profile + extra elements from XHTML + Backwards compatibility with WML 1 Protocols Wireless Profiled HTTP – compatible with HTTP 1.1 Wireless Profiled TLS – compatible with standard TLS Wireless Profiled TCP – compatible with standard TCP Other services in WAP 2 WAP Push: content sent from server without request User Agent Profile (UAProf): informs server about the client through the request Wireless Telephony Applications: Gives access to phone functionality – phone, send sms Persistent storage interface: Gives access to device storage Data synchronization Multimedia Messaging Service (MMS) For Nokia Series 60 more services on newer models WAP 2.0 Molde University College INF 245 Fall 2007 OBø

  19. When are thin clients the solution? Challenges Heterogeneous terminals Limited and expensive bandwidth Latency time Mobile context of use Security and integration User interface Why is it so hard to show standard www-pages on a mobile device? Limited HTML and CSS support Small screen Missing or weak support for scripting Missing plug-ins: Flash, Applets, PDF Graphics require bandwidth Graphics are commonly used for design Missing mouse Thin client development Molde University College INF 245 Fall 2007 OBø

  20. WAP changes in Telenor tariffs H2004-H2005 H 2004 BedriftskunderH2005 !! Molde University College INF 245 Fall 2007 OBø

  21. Reduce latency problem Reduce number of requests Reduce number of bytes Good navigation Few screens Must permit single handed navigation Simplicity – content more important than design Reduce amount of text Personalization Adapt content to user to give maximum usefulness User configurable? Different application for different users Message based approach: information about your flight! User interface design Molde University College INF 245 Fall 2007 OBø

  22. Testing of mobile web applications • Early testing necessary – why? • Pilot • It is necessary but not possible to test all possible terminals/browsers • Emulators • Both help and problem Molde University College INF 245 Fall 2007 OBø

  23. A browser for the desktop and for the mobile device is not the same Konsekvenser? Molde University College INF 245 Fall 2007 OBø

  24. Martyn Mallick kap 11, 12, 13, 14 Wapforum LTD(2002): Wireless Application Protocol WAP 2.0 Technical White Paper Jonny Axelsson (2004) Making Small Devices Look Greathttp://my.opera.com/community/dev/device/ Michael Ball (2000) XSL gives your XML some style http://www.javaworld.com/javaworld/jw-06-2000/jw-0630-xsl_p.html Nokia (2004) Series 60 Platform white paper: Browsing on Mobile Devices, NOKIA Corporation, July 2004 Sources Molde University College INF 245 Fall 2007 OBø

More Related