Transcript WAP - WordPress.com

Wireless Application Protocol (WAP)
Definition of WAP
Wireless application protocol (WAP) is an application
environment and set of communication protocols for
wireless devices designed to enable access to the Internet
and advanced telephony services
to the wireless
community.
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Develop By WAP Forum, Summer 1997
WAP 1.0 Standard, 1998
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Open Standard
Industry-Wide Specification
WAP 2.0 Standard, 2002
What is WAP
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WAP – The Wireless Application
Protocol
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Makes it possible to access the Internet via
wireless devices such as mobile phones, PDAs
etc.
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Set of rules governing transmission/reception of
data by wireless devices (e.g. mobile phones)
Limitations of Internet for Wireless Applications
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Traditional Internet applications cannot run on
mobile devices because of the following
limitations:
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Low bandwidth network
High Latency network
Limited connection stability
Small display size
Limited input facility
Limited memory
Limited processing power
Limitations of Internet for Wireless Applications
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Low bandwidth
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Size of an HTML page, including graphics
Download time (56Kbps modem)
Bandwidth of wireless network
9.6Kbps
Download time for data on one page
… 20 KB
…3s
…
… 17 s
High latency
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At the expiry of retransmission timer value, the TCP layer resends
the packet of data
An average latency in a wireless network is around ½ s but can be as
high as 10s
This can cause a lot of retransmission causing severe congestion
Limitations of Internet for Wireless Applications
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Limited connection stability
Small display size
Limited input facility
Limited memory
Limited processing power
What can be done with WAP?
Information services
Similar to web browsing
Small downloadable programs
WAP script language is based on JavaScript™
Telephony functionality combined with browser
Call the airline when your flight is delayed
Push
Server initiated content push
What is defined in WAP?
 Layered telecommunication stack including
 Datagrams and Transactions
 Security
 Session
 Micro browser
 Concept that is similar to the Internet browsing
 XML based markup language ( WML )
 Scripting ( WMLS )
 WTA / WTAI
 Access to telephone functionality
 Content formats e.g.
 Service Indication
 Wireless Bitmap ( WBMP )
WAP Architecture
WML
WMLScript
WTAI
Etc.
Web Server
WAP Gateway
WML Encoder
WSP/WTP
WMLScript
Compiler
Protocol Adapters
HTTP
CGI
Scripts
etc.
Content
WML Decks
with WML-Script
Client
How It Works
7
2
3
Request
Encrypted URL
Request
Client
WMLScript
WTAI
Etc.
Web Server
WAP Gateway
WML
Response
Encrypted WML
Content
6
WAP
4
HTTP Request
xxx wml
Encoder,Decode
r
WMLScript
Compiler
Protocol Adapters
CGI
Scripts
etc.
HTTP Response
xxx wml
5
HTTP
WML Decks
with WML-Script
1
Static file or CGI
Output WML
Content
Internet and WAP architecture
Internet
Wireless Application Protocol
HTML
JavaScript™
Other Services and
Applications
Wireless Application
Environment (WAE)
Wireless Session Layer (WSP)
HTTP
Wireless Transaction Protocol (WTP)
TLS - SSL
Wireless Transport Layer Security (WTLS)
TCP/IP
UDP/IP
Wireless Datagram Protocol (WDP)
Bearers:
SMS
USSD
CSD
R-Data
Packet
UDP
PDC-P
Etc...
WAP & Standards
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Submit specifications for adoption by appropriate industry and
standards bodies
Good relationships with standards bodies
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Several Liaisons with ETSI
ETSI / WAP compliance profile for GSM and UMTS.
CTIA official Liaison Officer to the WAP Forum
WAP is actively working with the W3C and IETF
WAP Protocol Stack
Wireless Session Service Access Point
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Developed by
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Wireless Protocols
Group (WPG)
A WAP technical
working group.
Wireless Session Protocol
Wireless Transaction Service Access Point
Wireless Transaction Protocol
Transport Service Access Point (TSAP)
Wireless Datagram Protocol
WCMP
Bearer
Bearer Service
Bearer Service
C
Service
B
A
Bearer
Service
D
Physical Layer Air Link Technology
WAP Protocols
Recall the ISO OSI model:
• WAE (Wireless Application Environment): WML, WML Script
• WSP (Wireless Session Protocol) and WTP (Wireless
Transaction Protocol): together provide session layer services
connection oriented sessions or connectionless sessions. Reliable
sessions can be resumed.
• WTLS (Wireless Transport Layer Security) (Optional)
WAP Protocol Stack - WSP
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Provides shared state between client and server used to
optimize content transfer
Provides semantics and mechanisms based on HTTP 1.1
Enhancements for WAE, wireless networks and “low-end”
devices
Enhancements beyond HTTP
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Binary header encoding
Confirmed and non-confirmed data push
Capability negotiation
Suspend and resume
Connectionless service
WAP Protocol Stack - WSP
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Binary header encoding
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Capabilities
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Compact binary encoding of headers, content type identifiers and other
well-known textual or structured values
Reduces the data actually sent over the network
Message Size, client and server
Protocol Options: Confirmed Push Facility, Push Facility, Session
Suspend Facility, Acknowledgement headers
Maximum Outstanding Requests
Extended Methods
Header Code Pages
Suspend & Resume
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Allows the release of underlying bearer resources
WAP Protocol Stack - WSP
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Connection & Connectionless service
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Connection-mode
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Long-lived communication
Benefits of the session state
Reliability
Connectionless
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Stateless applications
No session creation overhead
No reliability overhead
WAP Protocol Stack - WTP
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Reliable data transfer based on request/reply paradigm
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No explicit connection setup or tear down
Data carried in first packet of protocol exchange
Seeks to reduce 3-way handshake on initial request
Supports
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retransmission of lost packets
selective-retransmission
segmentation / re-assembly
port number addressing (UDP ports numbers)
flow control
abort function for outstanding requests
concatenation of PDUs
Message oriented (not stream)
WAP Protocol Stack - WTLS
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Specifies a framework for secure connections, using protocol elements
from common Internet security protocols like SSL and TLS.
Provides connection security for two communicating applications
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Privacy (encryption)
Data integrity (MACs)
Authentication (public-key and symmetric)
Lightweight and efficient protocol with respect to bandwidth, memory and
processing power
Employs special adapted mechanisms for wireless usage
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Long lived secure sessions
Optimised handshake procedures
Provides simple data reliability for operation over datagram bearers
WAP Protocol Stack - WDP
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WDP provides a connection-less, unreliable datagram
service
WDP is adapted to each particular wireless network to
provide the generic datagram transport.
The basic datagram service is fundamental to all wireless
networks and makes it possible to utilize WAP everywhere
Replaced by UDP when used over an IP network layer.
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WDP over IP is UDP/IP
Uses the Service Primitive
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T-UnitData.req .ind
WAP Protocol Stack - Bearer support
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GSM SMS, USSD, C-S Data, GPRS
IS-136 R-Data, C-S Data, Packet
CDMA SMS, C-S Data
PDC C-S Data, Packet
PHS C-S Data
CDPD
iDEN SMS, C-S Data, Packet
FLEX and ReFLEX
DataTAC
WAP: Applications
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Location-based services
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Enterprise solutions
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Schedules and rescheduling, Reservations
Gaming and Entertainment
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Banking, Bill-paying, Stock trading, Funds transfers
Travel services
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Email access, Database access, “global” intranet access
Information updates “pushed” to WAP devices
Financial services
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Real-time traffic reporting, Event/restaurant recommendation
Online, real-time, multi-player games
Downloadable horoscopes, cartoons, quotes, advice
M-Commerce
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Shopping on the go
Instant comparison shopping
Location-based special offers and sales
FUTURE OF WAP
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Will WAP comply with Third Generation wireless standards?
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Yes, WAP has been designed to be as independent as possible from the
underlying network technology.
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Is WAP necessary with higher bandwidth 3G networks?
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Even as bandwidths increase, the cost of that bandwidth does not fall to zero.
These costs result from higher power usage in the terminals, higher costs in the
radio sections, greater use of RF spectrum, and increased network loading. In
addition, the original constraints WAP was designed for -- intermittent coverage,
small screens, low power consumption, wide scalability over bearers and
devices, and one-handed operation -- are still valid in 3G networks. Finally, we
can expect the bandwidth required by application users to steadily increase.
Therefore, there is still a need to optimize the device and network resources for
wireless environments. We can expect WAP to optimize support for
multimedia applications that continue to be relevant.
FUTURE OF WAP
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If WAP is very successful in mass-markets on 2.5G networks, 3G networks may be
needed purely for capacity relief.
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The reasons to migrate to WAP technology
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Network operators are behind WAP
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With minimal risk and investment, WAP enables operators to decrease churn, cut
costs, and increase revenues by improving existing, value-added services and offering
exciting new informational services.
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Why are equipment manufacturers interested in WAP?
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Being a global open specification suite, WAP has generated the critical mass for
manufacturers. This has opened up new product and marketing opportunities in the
wireless industry and provides new revenue to participating companies.
ADVANTAGES
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open standard, vendor independent
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network-standard independent
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transport mechanism–optimized for wireless
data bearers
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application downloaded from the server,
enabling fast service creation and introduction,
as opposed to embedded software
DISADVANTAGES of WAP
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Small screens: For web phones, there's an incredibly small viewing
area; palmtops are barely better.
Speed of access: All devices have slow access.
Limited or fragmented availability: Wireless web access is sporadic in
many areas and entirely unavailable in other areas.
Price: Many technology limitations are being addressed by higher-end
devices and services. But the entry price for a good 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 overcoming the learning
curve to get the hang of it -- connecting, putting in an address, typing.
Users just aren't used to the idea and protocol yet.