Unwired Planet Position Paper for
W3C Workshop on Mobile Access

Corporate Background

Headquartered in Silicon Valley, USA, with overseas operations in the United Kingdom and Japan, Unwired Planet, Inc. (UP) is a leading supplier of open standards based servers and microbrowsers to the wireless industry. Unwired Planet's UP.Link Server Suite has been commercially available since 1996. Unwired Planet co-founded the Wireless Application Protocol (WAP) Forum with Ericsson, Nokia, and Motorola.

UP is happy to share its expertise with the W3C and looks forward to discussing our current solutions to the wireless data problems. It is our hope we can continue to work with both the W3C and WAP Forum to expand this exciting field with open, standard technology.

Experiences from Mass Market Telecommunications

UP has learned a number of lessons delivering web software products to the mobile telecommunications market and recommends the W3C consider this information in the future as it makes recommendations and decides courses of action.

The economic model, hardware capabilities, and physical form factor of mobile phones are significantly different from those of desktop computers.

Mobile phones will always have a much more constrained computational environment than desktop computers.
The limited displays of hand-held devices complicates the user interface and navigation problem spaces.
Input mechanisms on mobile phones will be much more limited than on computers.
New technology should be designed for the capabilities of today's devices.
Protocols must be designed to send the fewest number of messages and bytes over the air as possible.
User agents and applications must be very intelligent about when to send requests to the server.
Telecommunications specifications tend to be more rigorous than you find in the Internet.
Interoperability is a very high priority.

The primary use of wireless data on mobile phones and other small devices is not to peruse content, but rather to gain immediate, interactive access to timely information.

Issues Related to W3C

UP recommends the following issues to the Workshop on Mobile Access for exploration.

Relationship of WML, XML, and HTML

WML is an XML-based markup language and incorporates features from HDML and HTML. Even though WML may be considered a super-subset of HTML, it is a different markup language. The design philosophy behind WML has been:

To base the language on XML and other Web technologies
To incorporate features of HTML where they make sense (text formatting, links, images, etc.)
To add features that address the constraints of wireless networks and mobile phones, for example:

Explicit navigation
Client state
Deck and Card content structure

UP's position regarding WML, XML and HTML is:

XML, HTML and CSS are the central language technologies of the World Wide Web.
WML is a great example of using XML in the manner for which it was conceived and designed, i.e. a domain specific markup language.
The constraints of mobile phones and other small devices are very different from the design center of HTML.
WAP is doing a good job of mapping W3C technology to the mass market, wireless data space.
Future versions of XML, HTML, and CSS may want to incorporated some of the ideas from WAP.
A universal display language would benefit the industry, and UP believes it must address the needs of these microbrowsers.

Proxies in the wireless network

The UP and WAP architectures rely heavily on the use of intelligent proxies to offload computation and state management from the wireless devices, allowing smaller and less capable devices to access the web. UP recommends the W3C consider initiating some research into the issues of providing proxy services to wireless networks, and perhaps adopting some of the work specified by the WAP Forum. Issues that UP and WAP have already explored include:

Content transformation
Header filtering
Protocol translation
Security

Optimizing Communication between Client and Server

Because of the network costs associated with wireless data, it is critical to optimize communication between client and server. UP and WAP have taken the following approaches to reduce communication overhead.

Compact encodings
Remove redundant transmissions
Protocol optimization

UP recommends the W3C study and/or adopt the content encoding and protocol technologies developed by the WAP Forum.

March 20, 1997 PFK