Download WAP Protocol Stack

Wireless Application
Protocol Intro (Continued)
WebTP Meeting
H. Wilson So
28 Feb, 2000.
Outline
Recap: What is Wireless Application
Protocol? Architecture Overview
Wireless Session Protocol
Wireless Application Environment
architecture (WML & WML-Script)
Recap
… from last week
What is WAP?
"WAP specifies an application framework
and network protocols for wireless devices
such as mobile telephones, pagers, and
personal digital assistants (PDAs)."
WAP defines its own set of protocols but
models after existing web protocols.
WAP vs. IP world
GSM, CDMA, IS-136
WDP (datagram)
WTLS (security)
WTP (transaction)
WSP (session)
WML (markup)
WML Script (scripting)
IP
UDP
TLS (from SSL)
no counterpart
HTTP
HTML
JavaScript
Rationale: reuse as much as possible from IP world,
but optimize for the wireless world (i.e. compression,
adapt to high-loss rate.)
WAP Protocol Architecture
Protocol Features
Part I
Wireless Session Protocol
Wiress Session Protocol
Currently defined WSP services include
only browsing services WSP/B
WSP/B is a binary equivalent of HTTP/1.1
WSP Features Highlight
Supports both connection-oriented and
connectionless modes
Pull: Support all HTTP/1.1 request
methods (GET, PUT, POST, etc.)
(confirmed and non-confirmed)
Push: Server push (confirmed, nonconfirmed)
Suspend/Resume sessions independent of
transport sessions
Session Establishment /
Termination
Session Establishment
(over WAP Class 2)
Transaction Example
Method Invocation (over
WTP Class 2)
Session Suspend/Resume
Suspend (over WTP
Class 0)
Connectionless Session
Service
Provides unconfirmed (no ack or retx)
facilities for:
Method Invocation (GET, POST)
and
Push
Part II
Wireless Application
Environment (WAE)
What is WAE?
Specifies an application framework for
wireless devices such as mobile
telephones, pagers, and PDAs.
Defines a model suitable for buliding
interactive applications that function well
in narrow-band environment with
medium to high latencies.
WAE Model
Components of WAE
User Agents: in-device software that
retrieves and displays content to the user.
Understands WML and WML-Script
Gateways: Conversion between HTTP &
WSP and/or HTML & WML
Various WAE specific formats: WML, WMLScript, WBMP(bitmap)
Sample WML Page
 <WML>
<CARD>
Choose <I>all</I> you like:
<SELECT KEY=“X” ….. >
<OPTION VALUE=“D”>Dog</OPTION>
<OPTION VALUE=“C”>Cat</OPTION>
<OPTION VALUE=“H”>Horse</OPTION>
</SELECT>
</CARD>
</WML>