inf 245 mobile applications mobile thin clients a.k.a. wireless web

Molde University College INF 245 Fall 2007 OBø

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INF 245 Mobile Applications

Mobile thin clients a.k.a. Wireless Web

H 2007

Ola Bø


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(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


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dn.no3.9.2004

4 times more wap users from 2002Q4 to 2004Q2

1600 000 possible users 600 000 real users


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dn.no 28.5.2004

Nokia

Users prefer using their phone for browsing

Transition from WAP to HTML!


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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)


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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


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The Client 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

OpenWave RIM

Pocket IEPALM

WebClipping

Opera browser on Nokia series

60


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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


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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


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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

Mobile web applications – Common structure


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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.


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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?


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Processing of a wireless WWW request

1. Establish a wireless session2. Send a request

May be binary coded3. Translate the request

Safety problem (WAP-gap)4. Receive request

ASP, JSF, JSP, Servlet, 5. Identify the client

What can we send to the client6. Process request

1. Retrieve requested information7. Adapt markup to client8. Return content

1. 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.


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Convergence in standarisation, mark up and protocols

OpenWave

HDML

DoCoMocHTML

WAP ForumWAP 1.0WML1998

+Motorola, Nokia, Ericsson+300 companies

+Location Interop Forum

+SyncML Initiative

+MMS Interop Group

+Wireless Village

2002

Open Mobile AllianceWAP2WML2 =XHTML MPWP-HTTP, WP-TCP, WP-TLSCC/PP – UAPROF CSS

W3CHTML4.01997

WWW standards

Special standards for mobile terminals

Not tcp/ip,but special protocols optimized for wireless slow connections

tcp/ip- og http- compatible but optimized for wireless slow connections

Backwards compatible with WAP 1.0

W3CXHTMLBasic2000W3C

XHTML

An augmenting number of devices support TCP/IPHigher bandwidth

Simplification:frames

Added C

SS

+WM

L1elements

IETF – Ordinary


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The WAP model 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


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WAP components 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


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WAP 2.0 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


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Thin client development 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


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WAP changes in Telenor tariffs H2004-H2005

H 2004

BedriftskunderH2005

!!


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User interface design

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!


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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


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A browser for the desktop and for the mobile device is not the same

Konsekvenser?


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Sources 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

http://my.opera.com/community/dev/device/

http://www.javaworld.com/javaworld/jw-06-2000/jw-0630-xsl_p.html

http://www.javaworld.com/javaworld/jw-06-2000/jw-0630-xsl_p.html

inf 245 mobile applications mobile thin clients a.k.a. wireless web

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