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Transcript of Chapter 4 Wap
8/7/2019 Chapter 4 Wap
http://slidepdf.com/reader/full/chapter-4-wap 1/17
What is WAP ?y WAP The Wireless Application
Protocoly Makes it possible to access the Internet via wireless
devices such as mobile phones, PDAs etc.
y Set of rules governing transmission/reception of databy wireless devices (e.g. mobile phones)
August 2002
8/7/2019 Chapter 4 Wap
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Why WAP?y WAP is an open technology based on Internet technologiesy Allows competition - lower cost
y WAP is backed by major vendors
yNokia, Ericsson, Motorola, Microsoft, IBMyFuture proof
y WAP Forum is open for ally WAP is not take it or leave ityOver one hundred companies have joined the WAP Forum
y WAP supports several wireless systemsyGSM, IS-136, CDMA, PDC etc.
y WAP has a layered architectureyThe same application can be used via several systems
8/7/2019 Chapter 4 Wap
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Limitations of Internet for
Wireless Applications
y Traditional Internet applications cannot run onmobile devices because of the following
limitations:y Low bandwidth network
y High Latency network
y Limited connection stability
y Small display size
y Limited input facility
y Limited memory
y Limited processing power
August 2002
8/7/2019 Chapter 4 Wap
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Limitations of Internet (contd)y Low bandwidth
y Size of an HTML page, including graphics 20 KB
y Download time (56Kbps modem) 3 s
y Bandwidth of wireless network 9.6Kbps
y Download time for data on one page 17 s
y High latency y At the expiry of retransmission timer value, the TCP layer
resends the packet of data
y An average latency in a wireless network is around ½ s but can beas high as 10s
y This can cause a lot of retransmission causing severe congestion
August 2002
8/7/2019 Chapter 4 Wap
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WAP Programming Model
CGI,
Scripts,Etc.
C onten
t
Web Server
C lient
WA EUser Agent
Request(U RL)
Response(Content)
Gateway
Encoders A ndDecoders
E ncoded
Request
E ncoded Response
8/7/2019 Chapter 4 Wap
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Internet
HTMLJavaScript�
HTTP
TLS - SSL
TCP/IPUDP/IP
Internet and WAP architecture
Wireless ApplicationEnvironment (WAE)
SMS USSD CSD R-Data Packet UDP PDC-P Etc...
Bearers:
Wireless Application Protocol (most imp question )
Wireless Session Layer (WSP)
Wireless Transport Layer Security (WTLS)
Wireless Datagram Protocol (WDP)
Other Services andApplications
Wireless Transaction Protocol (WTP)
8/7/2019 Chapter 4 Wap
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Wireless Application Environment (WAE)
� General-purpose application environment
based on a combination of WWW and
mobile telephony technologies.
� It defines the user interface on the phone. It
contains WML and WTA (Wireless
Telephony Application).
� Primary objective ± interoperable
environment.
8/7/2019 Chapter 4 Wap
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Wir l ss licati E vir t
(C t .)� WAE includes a micro-browser (Client software
designed to overcome challenges of mobile handhelddevices that enables wireless access to services suchas Internet information in combination with asuitable network ) server environment which provides
± WML
± WML script
± WTA
± Content formats
8/7/2019 Chapter 4 Wap
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Wireless Session Protocol (WSP)
�The WAP session protocol (WSP) layer providesa lightweight session layer to allow efficientexchange of data between applications
.
� Application layer with a consistent interface for two session services
± Connection-oriented service that operatesabove the transaction layer protocol (WTP)
± Connectionless service that operates above asecure or non-secure datagram service (WDP)
� O ptimized for low-bandwidth bearer networkswith long latency
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Wireless Transaction Protocol (WTP)
y R uns on top of a datagram service
y The WAP transaction protocol (WTP) layer
provides transaction support, adding reliability to
the datagram service provided by WDP.y Light weight transaction-oriented protocol
y Three classes of transaction services
y Unreliable one-way requests
y Reliable one-way requests
y Reliable two-way request-reply transactions
8/7/2019 Chapter 4 Wap
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Wireless Transport Layer Security (WTLS)
Based on industry-standard Transport Layer
Security (TLS) protocol
y O ptimized for use over narrow-band
communication channelsy Features:
y Data integrity
y Privacy
y Authentication
y Denial-of-service protection
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Wireless Datagram Protocol (WDP)
y The WAP datagram protocol (WDP) is theTransport layer that sends and receives messagesvia any available bearer network, including SMS,USSD, CSD, CDPD, IS±136 packet data, and
GPRS.
y O perates above the data capable bearer servicessupported by various network types.
y Provides a common interface to the upper layer protocols and hence they function independent of the underlying wireless network.
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Bearers
y Differing levels of quality of service with respect to
throughput, error rate, and delays
y WAP protocols are designed to compensate for or
tolerate these varying levels of service
y WDP specification lists the bearers that are supported
and techniques used to allow WAP protocols to run
over each bearer
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DISADVANTAGES of WAP
� Small screens: For web phones, there's an incredibly small
viewing area; palmtops are barely better.� Speed of access: All devices have slow access.
� Li mit ed or fragment ed avai labi l ity: Wireless web access issporadic in many areas and entirely unavailable in other areas.
� Pr i ce: Many technology limitations are being addressed byhigher-end devices and services. But the entry price for agood wireless web palmtop with decent display, keyboard,and speed is easily $700 to $900, not including monthly
access.
� Lack of user habit : It takes some patience and overcomingthe learning curve to get the hang of it -- connecting, puttingin an address, typing. Users just aren't used to the idea and
protocol yet.
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US A GE
- Corporate Applications: Sales force automation
where sales people use their WAP enabled handsets toget instant, direct access to the latest pricing, latest
news, competitive information any time, anywhere.
- Online Services:
Bank i ng: Users can get their current balance,
transfer funds between accounts and receive fax of a
mini-statement.
Elect roni c Commerce: Subscribers can use their handset just like their PC to purchase products and
services over the Web.
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- Tele services
Prepai d Servi ces: With a WAP-enabled phone, prepaid subscribers can see their current balance with
the press of a button. By pressing another button,they can also recharge their account by entering acredit card or voucher number into the handset.
- Personal Productivity
Emai l: Using WAP users can keep track of their email right from their handset.
- Others include:
- Interactive Chat
- Auctions
- Games
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What is iMode?
y Goal: Easily enjoy Internet services on mobilephone
y
Overlay on top of DoPa packet networky Subscriber:
y New, advanced services on mobile device
y Operator:
y A way to attract new users and increase revenuey Users charged on per-packet basis (~0.22
cents/128byte)
y Payment collection for third-party informationproviders