Current way of Producing/Accessing 

Wireless Internet Contents

and The Role of WAP Gateway



Sangyoon Oh

soh@csit.fsu.edu

Computational Science and Information Technology

Florida State University





1.Current way of Producing/Accessing Wireless Internet Contents



It is not clear whether the most wireless web site (wap.domain.com) have independent .wml content server or converting existing document (XML/HTML) to .wml, since client receive .wml content with all case. I just can assume by their way of working. The major Portal site, such as Yahoo.com and Lycos.com also have wap.domain.com. In Lycos, Java Server Page generate contents and returns .wml file. I assume that they have XML backend database and JSP works in between WAP server and database. Yahoo's contents looks like filtered HTML, because the result is not as good as Lycos case (some broken characters). Many WAP oriented site (Mostly, Europe based) have independent server architecture from WWW. Their contents type is .wml and Perl script on server side response to request.

 

So, how XML to WML converting is possible? The Cocoon, which is Java publishing framework, do convert XML into WML, HTML, and PDF, according to the apache site (http://xml.apache.org/cocoon/). So it is easy to think that wap.lycos.com get their content from backend database, of which format is XML. Filtering HTML contents into WML is not expected to have a good result as XML to WML, even though Pyweb.com claim that their product does it smoothly.



Another type of accessing Internet with wireless device is Web Clipping Application. WCA of Palm VII is a kind of template of HTML browsing. It has HTML forms and images already. We can say each icon is mini-browser itself. Even if contents (strictly speaking only some part of HTML file is) delivered over Wireless Media, it is not WAP compatible. 



So the bottom line is that the current WAP content is generated on Server side and several technologies are involved to produce it, except Web Clipping Application of Palm, which is done on both side. 







2. The role of WAP Gateway in Wireless Internet Architecture



A WAP Gateway is a piece of software, which do several functions in between WAP-enable device (Mobile Phone/PDA) and  Web Server. It does: 

1. Converting textual format of WML to compressed/binary format which is readable by the WAP device.

2. Translating the request from the WAP device to HTTP request for the web server.

3. Converting between TCP protocol of WWW and transport protocol of the WAP, WDP

4. Converting between SSL encryption of WWW and WTSL encryption of the WAP



Since a WAP server, which is normal web server and serves WAP contents contains a WAP gateway, the host of WAP content will have full control over the encrypted stream.



There are several different WAP gateway from venders (some of them are free). The Kannel WAP and SMS gateway is open source product and Phone.com, Nokia, Ericsson have WAP gateway product, which is custom built up for each Mobile service provider.