WAP
why another protocol
Johan Montelius
jm@sics.se
Why?
access to phone features
limited user interface
limited bandwidth
long delay
Solutions
• Limit the number of messages
– three-way hand shake
– client DNS lookup
– multiple HTTP requests
• Adapt to the phone
– black and white
– simple navigation
– API to access the phone resources
WAP 1.x
HTTP/TCP/IP
WSP/WTP/WDP
WML Browser
Gateway
WML Content
WAP 1.x
WAE
Wireless Application Environment
WSP
Wireless Session Protocol
WTP
Wireless Transaction Protocol
WTLS
Wireless Transport Level Security
WDP
Wireless Datagram Protocol
Bearer
(GSM, CSD, USSD, CDPD, SMS ..)
WDP
Wireless Datagram Protocol
• a transport layer
– source and destination port
– segmentation and reassembly
• implemented on top of several bearers
– GSM, GPRS, CDPD, cdmaOne, PHS, DECT,
Mobitex, SMS ….
• similar to IP + UDP
Why WDP ~ UDP
• The link from the mobile terminal to the
the fixed side of the WDP connection
does not contain any routers.
• There is no need for flow control,
congestion control etc.
WTP
Wireless transaction layer
• Unreliable request
– used to push information to a mobile terminal
• Reliable request
– Same as above push + ack
• Reliable request and reply
– Used by mobile terminal to request information
– get + reply + ack
• Several transactions in one session
WSP
Wireless Session Protocol
•
•
•
•
•
•
reliable session
suspend resume a session
binary HTTP/1.1
push content
connection oriented (over WTP)
connectionless (over WDP)
The WAP gateway
WAE
WAE
WAE
WAE
WSP
WSP
HTTP
HTTP
WTP
WTP
WTLS
WTLS
SSL
SSL
WDP
WDP
TCP
TCP
The security loop hole
WAE
WAE
WAE
WAE
WSP
WSP
HTTP
HTTP
WTP
WTP
WTLS
WTLS
SSL
SSL
WDP
WDP
TCP
TCP
Who should own the gateway
Mobile
Operator
Content
aggregator
Service
provider
WAE
Wireless Application Environment
the browser
WML/Script
User profile
UaProf
security
WIM
access to the phone
WTA
WML 1.2
Wireless Markup Language
• XML based
• One wml-deck consisting of several wmlcards.
• Phone adapted navigation
• Limited presentation (b/w, no positioning etc.)
• WMLScript (ECMAScript ~ JavaScript)
• Event based
• Variables
WML example
<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.2//EN"
"http://www.wapforum.org/DTD/wml12.dtd">
<wml>
<card id="main" title="jmT2">
<p><a href="#intro">About</a></p>
<p><a href="gallery.wml">Photos</a></p>
<p><a href="t68i.wml">T68i</a></p>
</card>
<card id="intro" title="What" >
<p> This WAP site is only here as a an experiment.
</p>
</card>
</wml>
Why did WAP fail?
Did it fail or did it not live up to the hype?
WAP 2.0
WAE
WML2 - XHTML Basic
HTTP
TLS
TCP
IP
Wireless profiled TCP
Wireless profiled TCP
•
•
•
•
•
Defined in RFC …..
Header compression
Larger window size
Larger segment size (path MTU discovery)
….
WAP 2.0 gateway
WAE
WAE
HTTP
HTTP
TLS
TLS
TCP*
IP
TCP*
IP
* Wireless Profiled TCP
TCP
TCP
IP
IP
WML2 – XHTML Basic
•
•
•
•
•
•
Anchor images
Positioning of content
Color – gif, jpeg
Style sheets - CSS Mobile profile
check box, radio button
…..
WAP 2.0 vs iMode
iMode, EzWeb, Jsky