Method and system for secure communications

Abstract

A communications system and methods for securely transmitting a message between a wireless client and a proxy server are provided. A method for transmitting a message from the wireless client to a proxy server is provided. The message includes at least one packet of data and is encrypted using a data encryption key. The data encryption key is encrypted using a proxy server public key prior to sending the encrypted data encryption key to the proxy server. A method for transmitting a message from the proxy server to the wireless client is also provided. The proxy server recovers the data encryption key using the proxy server private key corresponding to the proxy server public key. The proxy server encrypts the message using the data encryption key and transmits the encrypted message to the wireless client. A communications system for secure communications comprising a source of data, a proxy server and a wireless client is also provided. Each transaction in the communications system comprises at least one request message and at least one response message. For each transaction, the wireless client encrypts a data encryption key using a proxy server public key. Messages exchanged between the wireless client and the proxy server are encrypted using the transaction specific data encryption key.

Claims

What is claimed is:

1. A method for securely transmitting a message from a wireless client, the method comprising:

encrypting a local key using a public key to form an encrypted local key, the local key corresponding to a request to contact a proxy server;

encrypting the message using the local key to form an encrypted message; and

transmitting the encrypted message to the proxy server, the encrypted message comprising at least one packet of data.

2. The method of claim 1, wherein each packet of data is formatted according to a compact transfer protocol.

3. The method of claim 1, further comprising generating the local key by,

applying a secure hash to a first input to form a first multibit hash, the first input comprising a concatenation of an output from a random number generator and at least one other character string; and

applying a message digest function to the first multibit hash to form the local key.

4. The method of claim 1, wherein the specific transaction comprises a single request message and each packet of data is less than one kilobyte.

5. A method for securely transmitting a message from a wireless client, the method comprising:

encrypting a local key using a public key on a proxy server to form an encrypted local key, the local key corresponding to a specific transaction between the wireless client and the proxy server;

encrypting the message using the local key to form an encrypted message; and

transmitting the encrypted message to the proxy server, the encrypted message comprising at least one packet of data, and a request message corresponding to a hypertext document, the encrypted request message further comprising encrypted request parameters, an encrypted bit, an encryption scheme identifier, a proxy server public key identifier, a proxy server identifier, a wireless client generated indication of current date and time, an encrypted request message integrity check, and the encrypted local key, the encrypted request parameters created from request parameters using the local key, the request parameters including compressed representations of data corresponding to fields in the hypertext document, the compressed representations formatted according to a compact transfer protocol, the encrypted request message integrity check encrypted using the local key.

6. The method of claim 4, further comprising signaling the encrypted request message to the proxy server with information to validate the encrypted request message.

7. A method for securely transmitting a message from a proxy server to a wireless client comprising:

receiving a message to be transmitted to the wireless device;

receiving an encrypted local key corresponding to a specific transaction between the proxy server and the wireless client;

decrypting the encrypted local key using a public key on the proxy server;

encrypting the message using the local key to form an encrypted message; and

transmitting the encrypted message to the wireless client.

8. The method of claim 7 wherein, the message comprises compressed data in a compact markup language.

9. The method of claim 7 wherein, the specific transaction comprises a single response message, and each packet of data is less than one kilobyte.

10. The method of claim 7, wherein prior to transmitting the encrypted message to the wireless client, the method further comprises:

computing a response message integrity check;

encrypting the response message integrity check using the local key to form an encrypted response message integrity check, the encrypted response message further comprising the encrypted response message integrity check.

11. The method of claim 10, further comprising after the transmitting step:

the wireless client receiving the encrypted response message;

the wireless client recovering the response message integrity check from the encrypted response message integrity check using the data encryption key; and

the wireless client verifying the response message integrity check.

12. A method for securely transmitting a message from a proxy server to a wireless client comprising:

receiving an encrypted request message comprising encrypted request parameters, a wireless client generated indication of current data and time, and a proxy server identifier, the encrypted request parameters formed by encrypting request parameters using the local key;

receiving an encrypted wireless client generated request message integrity check, the encrypted request message integrity check formed by encrypting a wireless client generated request message integrity check using the local key, the wireless client generated request message integrity check formed from a concatenation of the request message parameters, the wireless client generated indication of current data and time, and the proxy server identifier;

receiving a local key that was encrypted on the wireless client using a public key stored on a proxy server, the local key corresponding to a specific transaction between the proxy server and the wireless client;

decrypting the local key using a proxy server public key;

encrypting the message using the local key to form an encrypted message; and

transmitting the encrypted message to the wireless client.

13. The method of claim 12, further comprising:

recovering the client generated request message integrity check;

recovering the request message parameters;

computing a computed request message integrity check using the request message parameters, the wireless client generated indication of current data and time, and the proxy server identifier;

comparing the computed request message integrity check with the client generated request message integrity check;

responsive to the computed request message integrity check not matching the client generated request message integrity check, the proxy server throwing away the encrypted request message.

14. A system for secure communications comprising:

a source of data comprising means for transmitting markup language messages to a proxy server;

a wireless client coupleable to the proxy server, the wireless client comprising means for exchanging encrypted messages with the proxy server, the encrypted messages comprising encrypted request messages and encrypted response messages, each encrypted message comprising at least one packet of data, each encrypted request message comprising encrypted request parameters and an encrypted local key, the encrypted request parameters created by encrypting request parameters using the local key, the request parameters corresponding to fields in a hypertext document, the encrypted local key created by encrypting a local key on the wireless client using a proxy server public key, the local key corresponding to a transaction, the transaction comprising at least one request message and at least one response message, the HTML messages corresponding to the encrypted request messages; and

wherein the proxy server includes:

means for exchanging encrypted messages with the wireless client, each encrypted message comprising at least one packet of data;

means for fetching markup languages messages from the source of data;

means for recovering the local key from the encrypted local key using the proxy server public key;

wherein each encrypted request message further comprises an encrypted bit, an encryption scheme identifier, a proxy server public key identifier, a proxy server identifier, a wireless client generated indication of current date and time, and an encrypted request message integrity check.

15. The system of claim 14, wherein the request parameters comprise compressed representations of data corresponding to fields in the hypertext document, the compressed representations formatted according to a compact transfer protocol.

16. The system of claim 14, wherein the transaction comprises an encrypted single request message and an encrypted single response message.

17. The system of claim 14, wherein each packets of data is less than one kilobyte.

18. The system of claim 14, wherein the wireless client further comprises means for generating the local key.

19. A system for secure communications comprising:

a source of data comprising means for transmitting markup language messages to a proxy server;

a wireless client coupleable to the proxy server, the wireless client comprising means for exchanging a first encrypted message with the proxy server, the encrypted messages comprising encrypted request messages and encrypted response messages, each encrypted message comprising at least one packet of data, each encrypted request message comprising encrypted request parameters and an encrypted local key, the encrypted request parameters created by encrypting request parameters using the local key, the request parameters corresponding to fields in a hypertext document, the encrypted local key created by encrypting a local key on the wireless client using a proxy server public key, the local key corresponding to a transaction, the transaction comprising at least one request message and at least one response message, the HTML messages corresponding to the encrypted request messages; and

wherein the proxy server includes:

means for exchanging encrypted messages with the wireless client, each encrypted message comprising at least one packet of data;

means for fetching markup languages messages from the source of data;

means for recovering the local key from the encrypted local key using the proxy server public key; and

wherein the encrypted response message comprises a response message integrity check and compressed data in a compact markup language, the compressed data corresponding to a hypertext markup language message fetched per the encrypted request message, the compressed data comprising an indication of a bit size of the encrypted response message, an indication of whether the response is complete, and encrypted response message parameters, the proxy server further comprises:

means for validating the encrypted request message;

means for computing the response message integrity check; and

means for encrypting response message parameters and the response message integrity check, the means for encrypting comprising using the local key.

20. The system of claim 19, wherein the wireless client further comprises:

means for decrypting the encrypted response message integrity check and the response message using the local key; and

means for validating the response message integrity check.

21. A method for transmitting communications from a wireless device, the method comprising:

generating a local key on the wireless device responsive to a request for signaling a communication from the wireless device, the communication comprising at least one packet of data;

encrypting the local key using a public key located on a proxy server;

encrypting the communication using the local key; and

transmitting the encrypted communication and the encrypted local key to the proxy server.

22. The method of claim 21, wherein the communication includes a hypertext markup language message.

23. The method of claim 21, further comprising:

generating a message integrity check, the message integrity check including one or more parameters to enable the proxy server to check that the communication originated from the wireless device.

24. The method of claim 23, further comprising encrypting the message integrity check; and

transmitting the message integrity check as part of the communication to the proxy server.

25. The method of claim 21, further comprising:

receiving a request to transmit a hypertext document; and

wherein encrypting the communication includes encrypting the hypertext document.

26. A method for communicating with a wireless handheld computer, the method comprising:

receiving an encrypted local key generated on the wireless handheld computer;

decrypting the local key using a public key located on a server;

encrypting a message using the local key; and

signaling the message to the wireless handheld computer.

27. The method of claim 26, wherein receiving an encrypted local key includes receiving a communication from the wireless handheld computer, the communication comprising the local key.

28. The method of claim 26, further comprising receiving an encrypted communication comprising the local key, and decrypting the communication to identify the local key.

29. The method of claim 26, wherein signaling the message to the wireless handheld computer is responsive to receiving an encrypted message from the wireless handheld computer, the encrypted message including the encrypted local key.

30. The method of claim 26, further comprising receiving the message to be encrypted and signaled to the wireless handheld computer from a network.

31. A method for communicating with a wireless handheld computer, the method comprising:

receiving an encrypted communication from a wireless handheld computer;

accessing a public key;

recovering a local key from the encrypted communication using the public key; and

recovering a communication from the wireless handheld computer using the local key.

32. The method of claim 31, further comprising validating that the encrypted communication received from the wireless handheld computer.

33. The method of claim 32, wherein validating that the encrypted communication received from the wireless handheld computer includes identifying a time of day that the encrypted communication was signaled from the wireless handheld computer.

34. The method of claim 33, wherein validating the encrypted message received from the wireless handheld computer includes comparing the time of day that the encrypted communication was signaled from the wireless handheld computer with a time of day that the encrypted communication was received from the wireless handheld computer.

35. The method of claim 34, wherein receiving an encrypted communication from the wireless handheld computer includes receiving the time of day that the communication was signaled from the wireless handheld computer as part of the encrypted communication.

36. The method of claim 32, wherein validating that the encrypted communication received from the wireless handheld computer includes identifying at least one of a server identification for receiving the communication and a time of day.

Description

CROSS REFERENCES TO RELATED APPLICATIONS

This application relates to the following group of applications. Each application in the group relates to, and incorporates by reference, each other application in the group. The invention of each application is assigned to the assignee of this invention. The group of applications includes the following.

U.S. patent application Ser. No. 09/087,515, entitled "Method and Apparatus for Communicating Information over Low Bandwidth Communications Networks," filed May 29, 1998, having inventors Jeffrey C. Hawkins, Joseph K. Sipher and Scott D. Lincke.

U.S. patent application Ser. No. 09/087,563, entitled "Method, System and Apparatus for Packet Minimized Communications," filed May 29, 1998, having inventors Ronald Marianetti II, Scott D. Lincke, and Jeffrey C. Hawkins.

U.S. patent application Ser. No. 09/086,888, entitled "Method and System for Secure Communications," filed May 29, 1998, having inventors Ronald Marianetti II and Scott D. Lincke.

U.S. patent application Ser. No. 09/087,552, entitled "Method and System for Wireless Internet Access," filed May 29, 1998, having inventor Jeffrey C. Hawkins.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosures, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.

THE FIELD OF THE INVENTION

This invention relates to the field of information communications. In particular, the invention relates to low bandwidth network access to Internet based information.

BACKGROUND OF THE INVENTION

Wireless communications provides one method for mobile users to communicate to a wired network. In particular, wireless communications allows consumers to receive and send information. Examples of such wireless networks include cellular phones, pager systems, and satellite systems. The wireless network systems can be broken into relatively high bandwidth and low bandwidth systems. High bandwidth systems are for example satellite systems. Lower bandwidth systems include cellular phones and mobile radio systems. Still lower bandwidth systems include pager networks and low bandwidth packet switched radio systems (e.g., the BellSouth Mobile Data Mobitex.TM. system).

For users to access information on the Internet using wireless communications, the method in which they access the information is highly dependent on the type of wireless communications available to the user. For example on a high bandwidth network such as a wired network or a satellite system, the usual techniques for browsing data on the Internet are adequate.

An important source of Internet based data is the data accessible through the World Wide Web (referred to as the Web). The following describes the usual techniques for Web browsing. A user selects a web site associated with a URL (Uniform Resource Locator). The URL represents the address of the entry point to the web site (e.g., the home page for the web site). For example, the user may select a web site that supplies restaurant reviews. The user's computer (the client) makes an HTTP (HyperText Transport Protocol) request to the web server hosting the web site. The client typically needs to make multiple HTTP requests of the web server. For example, to load the restaurant locator home page, multiple HTTP requests are needed to download all the graphics, frame content, etc. Next, the user will typically need to browse through a number of linked pages to get to the page from which a search for restaurants can be made. Even if the user is immediately presented with the desired page, a great deal of information has had to been downloaded from the web site (e.g., graphics, advertisements, etc.). This additional information makes for a visually rich browsing experience. The user fills in the information on this page and selects a search button. The client makes another series of HTTP requests of the web server. The web server supplies the client with the requested information in an HTML formatted web page. The web page typically includes links to more graphics and advertisements that need to be accessed by the client.

For low bandwidth networks this technique does not work well. Too much bandwidth is needed to download the images. Also, low bandwidth networks typically charge per byte transmitted and can be very expensive if large amounts of data are downloaded. Thus, low bandwidth networks are desirable to use for accessing information on the Web but only if the amount of data transferred over the network is small. Specifically for packet data networks, the cost of transmitting messages increases with the number of packets transmitted. The cost of transmitting multiple packet messages is therefore a formidable obstacle for packet data network customer use.

One area in which Web access is becoming more desirable is in handheld devices. Handheld devices are emerging as important computer devices. Handheld devices typically implement a relatively small, but important function set. Examples of such handheld devices are the PalmPilot.TM. handheld device available from 3COM Corporation, Inc. of Santa Clara, Calif. Examples of the function set supported are address books, calendars, and task lists.

In the past, wireless communications with handheld devices have been performed using wireless modems, such as are available from Novatel Communications, Inc. of Calgary, Alberta, or wireless transceivers for dedicated wireless data access network. Essentially a wireless modem operates in the cellular phone network and supplies approximately 9600 baud bandwidth to the handheld device. This allows the user to access the web at a relatively low bandwidth.

An issue with using handheld devices to access the Web is related to their capabilities. Even if connected to a high bandwidth network, most handheld devices do not have the screen area or the processing power to display the graphics and large amounts of text in a typical web page. However, it is still desirable to support the browsing of information on the Web using handheld devices. It is further desirable that the handheld devices be able to use networks that have relatively low bandwidths.

Some of the methods by which previous systems addressed some of the issues described above are now described.

One method of reducing the amount of data transferred from the web site to the client is to cache the web site data locally on the client. For example, the Netscape Communicator.TM. browser application caches web pages on the client. Each cached web page is associated with a URL. Thus, when the client requests a web page, the Netscape Communicator browser attempts to use previously cached web pages before downloading the pages from the web site. Another type of caching program is NetAttache.TM., available from Tympany, Inc. of Mountain View, Calif. The NetAttache program downloads all the web pages from a given web site. The web pages are all cached on the client. A NetAttache server runs locally on the client. A browser can then be used to browse through the local copy of the web pages. The problem caching is that the pages still need to be retrieved from the server before they can be reused and there can still be a significant number of connections made to the web server.

Alternatively, some programs are customized for accessing specific information from particular web sites. Examples of these programs are Java applets that reside on the client or are served to the client by a server. The applets can then be reused to access information from a web site. An example of a specialized program for accessing specific information is the RealVideo Player from Real Networks, Inc. A problem with these types of programs is that they are very specific to a particular type of content. For example, they do not use standard HTML (hypertext markup language) constructs. This means that web site developers cannot use standard web site development tools to create their sites.

Therefore what is desired is an improved system and method for handheld device to access Internet information over relative low bandwidth networks.

SUMMARY OF THE INVENTION

The following summarizes various embodiments and aspects of the invention. Some embodiments of the invention include a method for securely transmitting a message from a wireless client. The method for securely transmitting a message from a wireless client comprises encrypting a data encryption key, encrypting the message using the data encryption key, and transmitting the encrypted message to a proxy server. The data encryption key is encrypted using a proxy server public key to form an encrypted data encryption key. The message comprises at least one packet of data.

Some embodiments of the invention include a method for securely transmitting a message from a proxy server to a wireless client. The method for securely transmitting a message from a proxy server comprises the following steps. The wireless client encrypts a data encryption key using a proxy server public key to form an encrypted data encryption key. The proxy server receives the encrypted data encryption key. The proxy server recovers the data encryption key using the proxy server private key corresponding to the proxy server public key. The proxy server encrypts the message using the data encryption key to form an encrypted message. The proxy server transmits the encrypted message to the wireless client. The message comprises at least one packet of data.

Some embodiments of the invention comprise a system for secure communications. The system comprises a source of data, a wireless client, and a proxy server. The source of data comprises means for transmitting an HTML message to the proxy server. The wireless client comprises means for exchanging encrypted messages with the proxy server. Each message is encrypted using a data encryption key to form an encrypted message. Each encrypted message comprises at least one packet of data. Each encrypted request message corresponds to a hypertext document. Each encrypted request message comprises encrypted request parameters, an encrypted bit, an encryption scheme field, an encrypted data encryption key, and encryption scheme specific parameters. The first portion of the encrypted request message corresponds to fields in the hypertext document. The encrypted data encryption key is created using a proxy server public key. The proxy server is in communication with the wireless client and the source of data. The proxy server comprises means for exchanging messages with the wireless client, means for fetching HTML messages from the source of data, and means for recovering the data encryption key using a proxy server private key corresponding to the proxy server public key.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures illustrate the invention by way of example, and not limitation. Like references indicate similar elements.

FIG. 1 illustrates a wireless communications device communicating with a web server.

FIG. 2 illustrates a method of communicating between a wireless communications device and a web server.

FIG. 3 illustrates an example user interface for a wireless communications device.

FIG. 4 illustrates a wireless network topology.

FIG. 5 illustrates a wireless network topology including a wireless network interface, a wireless network leased line, and a dispatcher.

FIG. 6 illustrates an example of a wireless communications device exchanging messages in a communications system.

FIG. 7 illustrates a reliable message protocol packet structure.

FIG. 8 illustrates an exchange of a single request packet and a single response packet using the reliable message protocol.

FIG. 9 illustrates an exchange of messages comprising a single request packet and two response packets using the reliable message protocol.

FIG. 10 illustrates an exchange of messages including a retransmit sequence using the reliable message protocol.

FIG. 11 illustrates lower level communication layers.

FIG. 12 illustrates the format of data passed between wireless client software layers.

FIG. 13 illustrates the format of an IP header and a UDP header.

FIG. 14 illustrates an alternative system for communicating between a wireless communications device and a web server.

THE DESCRIPTION

Table of Contents

CROSS REFERENCES TO RELATED APPLICATIONS

COPYRIGHT NOTICE

THE FIELD OF THE INVENTION

BACKGROUND OF THE INVENTION

SUMMARY OF THE INVENTION

BRIEF DESCRIPTION OF THE DRAWINGS

THE DESCRIPTION

TABLE OF CONTENTS

OVERVIEW

DEFINITIONS

SYSTEM INTRODUCTION

Browser

Browser and HTML Compatibility

Example Method of Communicating Between a Wireless Communication Device and a Web Server

Example User Interface

WIRELESS NETWORK TOPOLOGY

Intranet Topology

CONTENT LAYER

Compact Markup Language (CML)

Compact Data Structure Notation

CML Structure

CML Tags

Tag Definitions

HTML Element Functionality

The Head Elements

The Body

TRANSFER LAYER

Wireless Client Software Block Diagram

Compact Transfer Protocol

CTP Structure

CTP Requests

CTP Responses

CTP Data Types

CTP Commands

Hot Link Indices

Encoding Indirect Hyperlinks

Forms Processing

Encoding Normal Form Submissions

Encoding Server Dependent Form Submissions

Secure Communications

Security Requirements

Security Protocol

Strength and Possible Attacks

Encryption Algorithms

Administration

RELIABLE MESSAGE LAYER AND RELIABLE MESSAGE PROTOCOL

On Wireless Networks

The RMP Header

The RMP Data Area

Re-transmission of Lost Packets

The Reliable Message Protocol

On Wireless Networks

Reliable Message Layer Application Program Interface (API)

Using the Reliable Message Layer on the Wireless Communications Device

Implementation of RMP

Implementation of RMP on the Proxy Server

Implementation of RMP on the Wireless Communications Device

WIRELESS NETWORK INTERFACE

Structure of the Wireless Network Interface

Enhancements to the Network Library

HEADER COMPRESSION

The C-UDP Header

The C-UDP Header for Compressed Packets

The C-UDP Header for Generic UDP Packets

The C-UDP Header for Other IP Packets

PROXY SERVER DETAILS

COMMUNICATIONS SYSTEM DETAILS

Tunneling Support

ALTERNATIVE SYSTEM

THE CLAIMS

THE ABSTRACT

METHOD AND SYSTEM FOR SECURE COMMUNICATIONS

Overview

This overview section generally describes some of the more important features of various embodiments and then briefly reviews the material in the subsequent sections.

A significant challenge in creating a wireless information solution for handheld devices is providing a product that is both useful and practical given the severely limited bandwidth and high power requirements of a wireless radio. Hardware and software should be optimized to conserve battery power and to reduce the amount of traffic that is sent over the wireless link. The wireless communications device, of various embodiments of the invention, has programs for web access and two-way messaging. One of these programs can include most of the static data from a web site. The static data can be used to format a query to access the dynamic data from the web site. Each program can be for accessing a different web site. Importantly, only the amount of static data that is communicated is significantly reduced.

The wireless communications device communicates as part of a communications system. The communications system includes the wireless communications device, a server, and a source of data. The server acts as a proxy server. Typical sources of data are a web server or a mail server.

Some wireless networks, such as those provided for two-way pagers and other wireless packet data networks, provide wider coverage and lower cost than competing networks. These wireless networks typically have relatively low performance however. A single packet of 400 bytes can take eight seconds just to travel to the Internet and back when the system is lightly loaded. With such a low throughput, it could easily take minutes to download even a small web page using standard browser technology. The wireless communications system therefore employs novel methods for reducing the amount of traffic sent over the wireless link for web access.

A goal of the invention is to provide the user with fast access to web content. Although the wireless communications device can access generic web content, because of the wireless communications device's limited screen size, most existing content will not be as visually appealing, will be harder to navigate, and may take longer to access than specially formatted content. Thus, significantly advantages are achieved with customized content. The web content can be formatted for the small screens of most handheld communications devices. This content will download relatively quickly (because of its small size). The formatted content can be created and published using the same tools used today for desktop web publishing (i.e. HTML tools and web servers) and could even be viewed using a standard desktop browser. But,

A second goal of the invention is wireless messaging. To help achieve this goal, a proxy server facilitates communications between web servers, mail servers, and other Internet data sources and the wireless communications device. The proxy server improves performance for wireless networks. Because of the high latency and low bandwidth of wireless networks, using existing Internet protocols to directly access web servers from the wireless communications device would be prohibitively expensive and slow.

Another important factor to consider with wireless networks is latency. A minimum size packet has a round trip time of approximately three seconds on the low cost wireless network. Because of the large latency, the number of packets sent over the wireless link between the wireless communications device and the proxy server should generally be kept small. Thus, some embodiments of the invention are able to fetch most web pages and send or receive messages with just one packet up (wireless client.fwdarw.proxy server) and one packet down (proxy server.fwdarw.wireless client) over the wireless network. Thus, some of the more important features of various embodiments of the invention have been described. The following provides an overview of the sections in the detailed description.

The Definitions section provides definitions of terms used in the detailed description.

The System Introduction section provides an introduction to the various elements of the wireless communications system.

The Wireless Network Topology section introduces the protocols used to communicate between the various devices in the system.

The Content Layer section describes the markup languages used in the system.

The Transfer Layer section describes a compact transfer protocol (CTP) used for communicating between the wireless communications device and the proxy server.

The Reliable Message Protocol section describes reliable and efficient variable length message delivery over the wireline and wireless networks.

The Wireless Network Interface section describes a set of programs that can be used to access the wireless network as an IP network.

The Proxy Server Details section describes how the proxy server works with the content layer, the transfer layer, and the reliable message protocol.

The Communications System Details section describes how the content layer, the transfer layer, the reliable message protocol, the network interface and the proxy server can be used together.

Definitions

The following definitions will be helpful in understanding the description.

Computer--is any computing device (e.g., PC compatible computer, Unix workstation, handheld device etc.). Generally, a computer includes a processor and a memory. A computer can include a network of computers.

Handheld Device (or Palmtop Computer)--a computer with a smaller form factor than a desktop computer or a laptop computer. Examples of a handheld device include the Palm III.TM. handheld computer and Microsoft's palm sized computers.

User--any end user who would normally wish to retrieve information from the World Wide Web.

Internet--is a collection of information stored in computers physically located throughout the world. Much of the information on the Internet is organized onto electronic pages. Users typically bring one page to their computer screen, discover its contents, and have the option of bringing more pages of information.

Client--a computer used by the user to make a query.

Server--a computer that supplies information in response to a query, or performs intermediary tasks between a client and another server.

World Wide Web (or Web or web)--is one aspect of the Internet that supports client and server computers handling multimedia pages. Clients typically use software, such as the Netscape Communicator.RTM. browser, to view pages. Server computers use server software to maintain pages for clients to access.

Program--a sequence of instructions that can be executed by a computer. A program can include other programs. A program can include only one instruction.

Application--is a program or a set of hyper-linked documents.

System Introduction

FIG. 1 illustrates a wireless communications device communicating with a web server. In this example, the wireless communications device includes a handheld computer (or portable computer) having wireless communications capabilities. The handheld computer has predefined applications that correspond to a portion of the web site being served by the web server. Using the applications, a user can use to make queries of the web server. Some embodiments of the invention provide compression techniques that enable the wireless handheld computer to complete a web based information request using only one packet up to a proxy server and only one packet back down to the wireless communications device.

The following paragraphs first list the elements of FIG. 1, then describe how the elements are coupled, and then describe the elements in detail. FIG. 2 describes the operation of the elements.

This paragraph lists the elements of FIG. 1. FIG. 1 includes a wireless communications device 100, a base station 170, a proxy server 180, the Internet 190, and a web server 140. The wireless communications device 100 includes a screen 101 and is running an operating system 102. The operating system supports the execution of a browser 104. The browser 104 runs with the wireless application 106 and displays an example query form 105 and an example query response 107. Between the base station 170 and the proxy server 180 is a private network 172. The web server 140 includes a CGI (Common Gateway Interface) program 142. The CGI program 142 is responsible for generating the HTML page 144. FIG. 1 also includes a number of arrows indicating queries and responses. These queries and responses include a wireless CTP (Compressed Transport Protocol) query 122, a CTP query 124, an HTTP query 126, an HTTP response 136, a CTP response 134, and a wireless CTP response 132.

The following describes how the elements of FIG. 1 are coupled. The wireless communications device 100 communicates with the base station 170 via wireless communications. The base station 170 is coupled to the proxy server 180 via the private network 172. The proxy server 180, and the web server 140 are all coupled to the Internet 190.

The following paragraphs describe the elements of FIG. 1 in greater detail.

The wireless communications device 100 represents a handheld device that has wireless communications capabilities (also referred to as a portable computer or handheld computer with wireless communications capabilities). In one example system, the wireless communications device 100 includes a Palm III.TM. compatible handheld device having wireless communications capabilities. The wireless communications device 100 is for communicating over the BellSouth Mobile Data (BSMD) Mobitex system. Other embodiments of the invention support other wireless communications networks. Importantly, the BSMD Mobitex system is a relatively low bandwidth network. The embodiments of the inventions support querying of web based data using such a low bandwidth network.

The operating system 102 is an example of an operating system that can run on a handheld computer. Examples of such operating systems include the Palm OS.TM. operating system, available from the 3COM Corporation, of Santa Clara, Calif. The operating system 102 supports the running of applications. The operating system 102 also supports low level communications protocols, user interface displays, and user input.

The browser 104 is an example of a program (or group of programs) that supports some standard browsing features (e.g., displaying markup language documents, following hyper-links). The browser 104 is for generating queries and receiving responses. The browser 104 can interface with groups of hyper-linked, marked up documents (also referred to as pages). The browser 104 can also interface with standalone programs that do not use marked up documents. In this example, the browser 104 is executing with the wireless application 106. The browser 104 is described in greater detail below.

The wireless application 106 represents one of many predefined applications that are stored locally on the wireless communications device 100. Each wireless application represents a static portion of a web site tree. That is, this information does not change significantly over time. The web site tree is the data structure representing the hyper-linked web pages of a web site. (Note that the tree is actually usually a graph.) Each predefined application is used for accessing a different web site. The predefined applications can be downloaded to the wireless communications device 100 through wireless communications, but more typically, they are downloaded through a docking cradle or through infrared communications with another wireless communications device 100.

The wireless application 106, in this example, includes a number of hyper-linked pages. One of the pages includes the example query form 105. This example query form 105 is used to generate a query that is answered as the example query response 107. Alternatively, the wireless applications can standalone applications access through the browser 104. The applications can be C programs, JAVA programs, and/or compressed markup language (CML) or HTML pages.

The query response 107 represents the dynamic data in the web site tree (the data that can change often). The query response 107 includes information retrieved from the web server 140.

The example query form 105 and the example query response 107 can be stored in a CML format. The markup language is compressed relative to HTML. This compressed markup language is described in greater detail below. What is important is that the compressed markup language is a subset and superset of HTML and is requires far fewer bytes than URML typically requires. Additionally, the compressed markup language represents a compressed description of information to be displayed on the screen 101. The browser 104 uses the representation to generate the display on the screen 101.

The base station 170 represents a wireless communications base station. The BSMD Mobitex system includes base stations like the base station 170. The base station 170 is responsible for communicating with the wireless communications device 100 and other wireless communications devices (e.g. pagers).

The private network 172 represents the communications links between a base station 170 and a proxy server 180. The BSMD Mobitex system has such a private network. Between the base station 170 and the proxy server 180, many servers, routers, and hubs, etc. may exist. In some embodiments, the private network 172 may communicate with the proxy server 180 through the Internet 190. The proxy server 180 would then communicate with the web server 140, also through the Internet 190.

The proxy server 180 represents one or more computers that convert queries from the wireless communications device 100 into queries that are compatible with Internet protocols. The proxy server 180 communicates with the wireless network, which can include low bandwidth and high latency communications. The proxy server 180 decompresses information from the wireless network side for use on the Internet 190 side of the proxy server 180. Also, the proxy server 180 converts Internet protocols and content into a form that can be used by the wireless network and the wireless communications device 100. In some embodiments, the proxy server 180 can converts image content to a size and bit depth appropriate for display on the wireless communications device 100. In some embodiments, the proxy server 180 communicates over the Internet 190 using standard Internet protocols such as, TCP, HTTP, and SSL. This allows developers to use already existing Internet protocols in their web servers.

In some embodiments, the proxy server 180 is substantially stateless. That is, it does not keep state information about specific wireless communications device accesses. This configuration of the proxy server 180 tolerates communication and protocol errors more readily and allows for simpler scaling of the proxy server 180. Statelessness should not be confused with caching. The proxy server 180 can cache CML web pages for use by multiple wireless communications devices 100.

In order to achieve reasonable performance and cost over wireless networks, the browser 104 works in tandem with the proxy server 180. The wireless communications device 100 and proxy server 180 communicate with each other using a compressed transport protocol (CTP) built on top of IP. The goal of this protocol is to enable a user to fetch and display a web page on the wireless communications device 100 with a one packet request sent to the proxy server 180. Typically, a one packet response is returned to the wireless communications device 100.

In one embodiment of the invention, the maximum packet size (for higher protocol packets, like IP) allowed over a low cost wireless network is 512 bytes. Taking into account a compressed header (usually three bytes), the maximum raw data size is 512-3=509 bytes.

The proxy server 180 transmits a typical page of web content to the wireless communications device 100 in roughly 500 bytes. This can be challenging given that most web pages have lots of formatting information, hot links and images. Web pages are typically many Kbytes in size. A hot link reference can easily take up 100 bytes or more. Just to fill the wireless communications device screen 101 with text (11 lines of 35 characters each) would take nearly 400 bytes even if there were no formatting information included.

This is why the wireless communications device 100 and the proxy server 180 use compressed web pages.

The Internet 190 represents the Internet. However, the Internet 190 could be replaced by any communications network.

The web server 140 responds to web accesses. The web server 140 serves regular, and specially constructed, HTML pages. In this example, the wireless communications device 100 is accessing the special HTML pages (e.g., HTML page 144). The example query response 107 corresponds to the HTML page 144. In other embodiments of the invention, the same HTML page can be served in response to a query from the wireless communications device 100 as is served to other types of clients. The HTML page 144 is generated by the CGI 142. The CGI 142 represents a program that can dynamically generate HTML pages in response to HTTP requests.

Turning to the query and response elements, the wireless CTP query 122 represents a compact transfer protocol (CTP) formatted query from the wireless communications device 100. The base station 170 receives this query and forwards it to the proxy server 180. The forwarded query is represented by CTP query 124. The proxy server 180 takes the CTP query 124 and converts it into one or more HTTP queries 126. The web server 140 receives this HTTP formatted query 126 and generates an HTTP response 136 that includes the HTML page 144. The proxy server 180 receives the HTTP response 136, and generates the CTP response 134. The base station 170 generates the corresponding wireless CTP response 132. The wireless communications device 100 then generates the display on the screen 101 of the example query response 107. Before describing this process in detail, the browser 104 is described in greater detail.

Browser

The browser 104 and supporting wireless messaging programs comprise the client processing resources for some embodiments of the invention. The web browser 104 works well with both wireless and wireline connections, enabling users to seamlessly access the web whether they are connected through the phone line or not. The messaging support enables a user to send and receive wireless messages with other users that have Internet e-mail accounts.

The browser 104 support both wireless and wireline connections. An effective wireless browsing solution leverages the use of the proxy server 180 in order to deliver satisfactory performance. A solution embodied in the roles established for the wireless communications device 100 and the proxy server 180 dramatically reduces the amount of data that is sent between the wireless communications device 100 and the proxy server 180 over the slow wireless link. This form of browsing is referred to hereinafter as thin browsing.

The performance of wireline links, on the other hand, is high enough that a wireless communications device 100 can talk directly to a source of data such as a web content server using standard Internet protocols such as HTML, HTTP and TCP. This is how existing desktop browsers work and will be referred to hereinafter as standard browsing.

Thin browsing can be used over wireline links as well as wireless links. The only extra requirement is that the proxy server 180 be accessible to the wireless communications device 100 over the Internet or an intranet. Standard browsing, on the other hand, is more appropriately used over wireline links because of increased chattiness and bandwidth requirements.

The browser 104 is structured as a single user-interface that runs either a standard browser engine or a thin browser engine. With either engine, the user interface essentially appears the same, and the way original HTML web content is interpreted and displayed will be almost identical. The browser 104 relies on the proxy server 180 for reducing the amount of traffic and the number of transactions required. Although designed primarily for use over wireless networks, the browser 104 can be used over wireline networks as well.

The primary purpose of the thin browser engine is for accessing content designed specifically for the limited screen 101 size and functionality of a wireless communications device 100. For some embodiments, this layout and size are the only differences between content rendered for a wireless communications device 100 and existing desktops. Thus, content creators for desktop content can use the same tools that are used for creating and publishing desktop content when creating and publishing content for the wireless communications device 100.

Content rendered for the wireless communications device 100 can reside on standard HTML based web servers in standard HTML format (e.g., see web server 140). The proxy server 180 performs a dynamic conversion of the HTML content into the more compact CML form before transmitting the content to the wireless communications device 100.

The browser 104 will not prevent a user from accessing desktop oriented sites, but the browser 104 can behave differently when accessing them. For example, graphics can be ignored when not accessing a wireless communications device friendly site whereas the user will have the option to enable graphics for wireless communications device friendly sites. Another example of the difference is the browser 104 protects the user from unintentionally downloading a large desktop oriented site. A user option enables the user to set the maximum size desktop page that may be downloaded. If a page is encountered which exceeds this maximum size, the page is clipped by the proxy server 180 before being sent down to the wireless communications device 100. The user is able to set this maximum size on a page per page basis in the favorites list of the browser 104.

When the user first launches the browser 104, the browser 104 is able to display the user's home page without sending or receiving even a single byte over the network. This is in contrast to the standard web browser that go over the network to fetch the home page, or at least to check that the locally cached version of the home page is up to date.

The browser 104 relies much more on pre-loaded content. A transaction typically takes place over the wireless network only when necessary. For example, in some embodiments of the invention, the browser 104 assumes that the locally cached form is up to date and only submits a network request to the proxy server 180 after the user fills in a form requesting an update.

Thus, the browser 104 is particularly suited for accessing real-time data, not casual browsing. Thus, emphasis is placed on optimizing the process of filling out a form (e.g., with airline flight information) then submitting the form, and getting the real-time data back. Although, the user will still be able to casually browse any web site, the increased cost and volume of data involved with going to most standard web sites makes casual browsing relatively undesirable over a wireless network.

A typical user scenario for the browser 104 would then be as follows. The user extends, or rotates, the antenna on the wireless communications device 100 and thereby automatically power up the wireless communications device 100. The browser 104 displays the user's home page (stored in local memory). The home page has been configured by the user with a set of service icons such as weather info, traffic info, airline info, stock quotes, etc. before the browser is used. The user clicks on one of the service icons, such as the airline information. This starts the corresponding wireless application which contains a form. The browser 104 displays the form (also stored in local memory) for the user to enter the flight number or city codes. The user enters the information in the form and hits the "submit" button. Now, for the first time in this scenario, the browser 104 sends a request out over the network to fetch the airline information. When the response comes back from the proxy server 180 (three to five seconds later), the information for that flight will be displayed on the screen 101.

As just described, there are a number of significant differences between the browser 104 and a standard web browser. First, the primary usage of the browser 104 is for accessing real-time data through form submittal. Second, most forms are pre-loaded into the wireless communications device 100 local memory or present in read only memory. Third, forms are assumed to be valid, and therefore no activity will take place over the network until the user actually fills in the form and submits it.

Browser and HTML Compatibility

The following describes the HTML compatibility of one embodiment of the browser 104. Other embodiments of the invention have different features.

In order to display most content published today on the Internet 190, the browser 104 supports the most common features of HTML. However, because of the screen size and limited memory and performance of wireless communications device 100, some HTML features may be limited in functionality or not supported at all.

Because of a limited number of available fonts and font styles, the browser 104 may not render every possible text attribute in HTML. A number of font sizes and styles map to the same font on the wireless communications device 100. However, the user does not encounter significantly reduced readability or usability as a result of the mapping.

The proxy server 180, as directed by the wireless communications device 100, can filters out all images, unless the user explicitly enables images, or the content author imbeds the appropriate tag into the content indicating that this page is wireless communications device 100 specific and that the images should be downloaded to the wireless communications device 100.

All text hyperlinks can be supported. If images are downloaded, then image maps will also work.

Forms will have nearly full functionality. The only feature of HTML forms that may not be supported is the use of dialogs that let the user choose a file name by browsing the local directory structure on the wireless communications device 100.

Tables that are too wide to fit on the screen can be wrapped.

CGI (Common Gateway Interface) scripts can be supported. CGI scripts are used by the web server 140 to respond to form submissions by browsers and for customizing web content for a particular user. When the browser 104 requests a web document that corresponds to a CGI script, the browser 104 can append text parameters to the end of the base document URL. The proxy server 180 will parse the parameters out of the URL and send them to an executable program on the web server 140, as identified by the URL. Most CGI executables will then output dynamically generated HTML that is consequently returned to the browser 104 and displayed. From the browser's 104 point of view then, fetching a web document that uses CGI scripts is no different from fetching a static web document (other than having a slightly more complex UTRL).

Example Method of Communicating Between a Wireless Communications Device and a Web Server

FIG. 2 illustrates a method of communicating between a wireless communications device and a web server. Such a method can be implemented using the system of FIG. 1.

The example method of FIG. 2 can be broken into three processes: a build a distributed web site process 202, a query process 204, and a response process 206. By using these three processes, a distributed web site can be created where static information is primarily kept on the wireless communications device 100 and dynamic information is kept on the web server 140.

At block 210, a content developer defines a wireless application. In one embodiment of the invention, this includes defining a number of HTML pages. The HTML pages represents the forms used for querying the web server 140. A program is then used to convert the HTML pages into compressed markup language pages to generate the wireless application 106. This process is discussed in greater detail below in the compressed markup language section.

At block 220, the web server 140 is created, or modified, to support reduced content HTML pages. An example of such a page is shown as HTML page 144. These pages can be generated exactly the same way as regular HTML pages. However, as a guiding principle, the amount of information should include little more than the absolute minimum of information that a user would find useful.

At block 230, a user loads the wireless application 106 onto the wireless communications device 100. This can be done as a HotSync.TM. operation in a manner similar to the way in which other applications are loaded onto the wireless communications device 100. The wireless communications device 100, for example, can be connected to a computer via a cradle and the wireless application 106 can be loaded from the computer. Alternatively, the wireless application 106 can be downloaded over the wireless network. However, this second method of loading the wireless application 106 is less desirable in that it will require a significant amount of bandwidth. Thus, in a preferred embodiment, the user loads the wireless application 106 over a high bandwidth network (e.g., the cradle download or by an infrared transfer from another wireless communications device 100).

Thus, some of the web site information is stored on the wireless communications device 100 and some of it is stored in the web server 140. Thus, the building of the distributed web site process 202 has been described.

The query process 204 includes the following steps. At block 240, the user fills in a query form 105 as part of the wireless application 106. In the example of FIG. 1, the user is filling out a form to find Italian restaurants in San Francisco. Once the user has completed the form, the user selects the look up button. The look up button causes the wireless communications device 100 to initiate the wireless CTP query 122. The block 240 is completed by the sending of the wireless CTP query 122 and the CTP query 124 to the proxy server 180. The wireless CTP query 122 is sent to the base station 170. The base station 170, and related hardware, perform any necessary changes to the wireless CTP query 122 to generate the CTP query 124, and send the CTP query 124 over the private network 172.

At block 250, the proxy server 180 converts the CTP query 124 to an HTTP query 126 and forwards that HTTP query 126 to the web server 140. Thus, the query process 204 is completed.

Now the response process 206 is described. At block 260, the web server 140 generates and sends an HTML page 144 to the proxy server 180. At block 260, the web server 140 generates the HTTP response 136 in response to the HTTP query 126. In this example, because the HTTP query 126 corresponds to a wireless communications device 100 query, the web server 140, and in particular the CGI 142, sends the HTML page 144 in the HTTP response 136. Returning to block 250, the conversion from the CTP query 124 to an HTTP query 126 may involve more than one HTTP request. This may occur where the web page has multiple referenced objects that need to be retrieved from the web server 140. Thus, the proxy server 180 may initiate multiple requests depending on the response in block 260. Note however, only one CTP request was needed.

At block 270, the proxy server 180 converts the HTML page 144 into the example query response 107 and sends the example query response 107 to the private network 172. The example query response 107 is inside of the CTP response 134, which is transmitted from the proxy server 180, across the private network 172, to the base station 170. The base station 170 then sends the corresponding wireless CTP response 132 to the wireless communications device 100.

The operating system 102 notifies the browser 104 that the wireless CTP response 132 has been received. The browser 104 requests the contents of the wireless CTP response 132 from the operating system 102. The contents are the example query response 107. Thus, at block 280, the browser 104 can display the example query response 107 on the screen 101.

Example User Interface

FIG. 3 includes a number of pictures showing an example display generated by the wireless communications device 100. These displays would be generated when a user attempts to find restaurants in San Francisco.

The wireless communications device 100 includes a launcher under which wireless applications can be grouped. The launcher interface 303 displays the list of available wireless applications. Note that the browser 104 is not specifically listed. This is because the user would typically only want to run a specific web site access application, not the browser 104 by itself. In this example, the user has selected "fine food" from the launcher interface 303.

In response to the selection, the example the browser 104 and the wireless application 106 begin executing. The browser 104 displays the example query form 105. The example query form 105 is a CML page in the wireless application 106. Then, the user can select/enter various field values for a query. In this example, the user is selecting the location field value "San Francisco".

The completed query form 305 is shown next. The user now wishes to send the query. This can be done by selecting the "look up" button. This sends the wireless CTP query 122 out through the network and to the web server 140. The wireless communications device 100 then receives the wireless CTP response 132.

The response includes the information for the example query response 107. The browser 104 displays the example query response 107 on the screen 101. Here a number of restaurant names and phone numbers are shown. The user can scroll up and down through the list.

Also presented on the screen 101 is a toolbar 310. The toolbar 310 allows the user to perform various functions within the browser 104. The toolbar 310 includes a back button, a connection indicator, and a drop down list. The back button allows the user to go back to the previous query form. The wireless communications indicator indicates whether the wireless communications device 100 is performing a wireless communications query. The drop down list indicates a history of the query results that the user has requested during past use of the browser 104.

Wireless Network Topology

FIG. 1 and FIG. 4 show the general topology of a wireless communications network. As shown, the wireless client 405 (in FIG. 4, the wireless communications device 100 and its software have been combined into the wireless client 405) communicates directly with the proxy server 180. The wireless client 405 does not communicate directly with the actual source of data. The source of data can be a web or mail server that has content desired by the wireless client 405. FIG. 1 shows the Internet 190 as the source of data and the source of data will be referred to as the Internet 190 throughout this application. Using this scheme, the wireless client 405 and the proxy server 180 can use a much more efficient ("thin") protocol between themselves than used by Internet mail and web servers. On the other hand, the proxy server 180 uses standard Internet protocols (HTTP, TCP) when communicating with existing mail and web servers. The proxy server 180 acts as an agent. The proxy server 180 takes requests from the wireless client 405, obtains the requested information from the Internet 190, and re-formats and sends the requested information back to the wireless client 405. The proxy server 180, acting in this manner, can hide the relatively chatty and bandwidth intensive protocols used by standard Internet 190 servers from the wireless link.

The thin protocols used between the wireless client 405 and the proxy server 180 are IP based. IP based protocols are widely used and enable the wireless client 405 to communicate with many different wireless networks. Furthermore, basing wireless client 405 and proxy server 180 processing resources on IP provides a layer of isolation and independence from the actual wireless network in use.

FIG. 4 shows a wireless network topology 400 used for some embodiments of the invention. The main components of the wireless communications system are the wireless client 405, the wireless network access point 410, the tunneler 430, the proxy server 180, and the Internet 190. The wireless network access point 410 has a corresponding wireless network access point radio 420.

The wireless client 405 communicates across the wireless network using its own client radio 440 to transmit messages to and receive messages from the wireless network access point radio 420. The wireless network access point 410 is the nearest regional station in a wireless network with a connection to a proxy server 180. The wireless network is by nature not IP based, and its most basic packet type is referred to herein as wireless network protocol packet (WLNP). Consequently, the wireless client 405 encapsulates its IP packets with a WLNP header before the packets can be sent by the client radio 440.

The packets sent over the air include a number of headers in the following order: a WLNP header, followed by a compressed user datagram protocol (C-UDP) header, followed by a reliable message protocol (RMP) header. The headers encapsulate a Request/Response Message Fragment (RQMF/RSMF) of the packet. The RQMF/RSMF of each packet holds the message fragments. These fragments are commands, requests, and responses sent between a wireless client 405 and the proxy server 180 that enable a wireless client 405 to browse web pages, send and receive e-mail, and otherwise obtain access to content.

In some embodiments, the wireless network has guaranteed delivery built into it. For these embodiments, it is not necessary to incur the extra overhead of a full connection-oriented protocol such as TCP on top of the wireless network protocol. Instead, the wireless client 405 uses the Internet 190 UDP. The UDP is a simple datagram based, best effort delivery protocol. Using UDP, it is possible that a web page can be viewed from the wireless client 405 by sending just one packet up to the proxy server 180 and receiving just one packet back. The TCP protocol, on the other hand, would require a minimum of 5 packets back and forth between the proxy server 180 and the wireless client 405 to view the web page. The wireless network does not, on the other hand, guarantee order of delivery, so an RMP header is placed in front of the data area in each UDP packet. The RMP is used to detect and correct for out-of order or duplicate packet deliveries.

Instead of using raw UDP internet headers which are 28 bytes in length (20 bytes for the IP information, 8 bytes for the UDP information), the wireless client 405 uses a smaller, compressed form of the UDP header called C-UDP. A C-UDP header contains just enough information so that the actual IP/UDP header can be reconstructed at the other end of the wireless link. There are a number of fields in a standard IP/UDP header that are rarely changed and/or redundant over the wireless network and these fields can be highly compressed or left out altogether in the C-UDP header, as discussed in greater detail below.

The wireless network access point 410 receives WLNPs that have C-UDP packets imbedded in them. The WLNP header is stripped off the front of the packets by the tunneler 430 for the wireless network. The original IP header and UDP header are reconstructed, and the packets are then forwarded to the proxy server 180 through a TCP connection. Because an unreliable network (LAN or Internet) is used between the wireless network tunneler 430 and the proxy server 180, TCP is used to guarantee that the packets get transferred reliably.

The TCP stream that the proxy server 180 receives from the tunneler 430 has the imbedded IP packets. The IP packets contain request message fragments. The reliable message layer (shown in FIG. 6 as reference number 635) on the proxy server 180 reconstructs the original request message from the message fragments in the packets using the information contained in the RMP header area of each packet. The requested information (web page or e-mail) is then be fetched as a data object from the Internet 190, re-formatted, and passed back to the reliable message layer 635. Proxy server 180 processing resources operating in the reliable message layer 635 break down the data object into separate packets for transmission to the wireless client 405, and send the packets to the tunneler 430 through the TCP connection. The tunneler 430 forwards the packets back over the wireless network to the wireless client 405.

FIG. 5 illustrates the wireless network topology including a wireless network interface 510, a wireless network leased line 520, and a dispatcher 530. FIG. 5 shows how the wireless client 405 and proxy server 180 communicate when the wireless client 405 is on a wireless network. Notice that the wireless client 405 is directly on the wireless network whereas the proxy server 180 is not. The wireless packets do not get sent directly to the proxy server 180. Instead, they first pass through the base station 170, a wireless access point 410, and tunneler 430 before they are sent to the proxy server 180 over a wireline LAN (Local Area Network) connection.

Wireless client 405 processing resources send messages through the reliable message layer 635. Since the wireless client 405 is on a wireless network, the reliable message layer 635 uses the RMP protocol to send the messages. The RMP protocol encapsulates the message fragments with an RMP header and sends them through a UDP socket in the network library (shown as 1110 in FIG. 11 and discussed below). The packets work their way through the IP stack on the wireless communications device 100, which adds UDP header and IP header. The packets are passed down to the wireless network interface 510 for transmission.

The wireless network interface 510 then compresses the IP header and UDP header of the packet into a C-UDP header, and adds the wireless network protocol (WLNP) header. FIG. 5 shows the wireless network interface 510 adding a WLNP header that is used on the wireless packet data network. Other networks will have similar headers. Much of the information in the IP and UDP headers is redundant with the WLNP header, so the C-UDP header can be significantly smaller than the sum of the IP header and UDP header.

The WLNP encapsulated packets are sent over the radio and are received by a base station 170. The base station 170 passes them to a wireless network access point 410. The wireless network access point 410 then passes the packets through a wireless network leased line X.25 link to the tunneler 430. The X.25 link can be a 56 Kbps leased line or a high speed frame relay connection. Although FIG. 5 shows only one tunneler 430, two tunnelers are typically used for the wireless packet data network. In one embodiment, the first tunneler is part of the wireless packet data network infrastructure and is referred to as the "Internet Access Server" or IAS. The IAS tunnels the WLNPs from the wireless network access point 410 into a TCP stream and sends this stream to a proxy server 180 specific tunneler. The proxy server 180 tunneler takes each WLNP from the IAS stream and converts its WLNP/C-UDP headers into normal IP/UDP packet headers. Thus, at this point in the chain of events, the packets look identical to the way they looked when the wireless client 405 first passed them to the wireless network interface 510 on the wireless communications device 100.

The tunneler 430 then sends its output stream to a dispatcher 530. The dispatcher's job is to load balance among multiple proxy servers 180. The dispatcher 530 distributes wireless client 405 requests that the dispatcher 530 receives from the tunneler 430 among a set of proxy servers 180. In order to do this, the dispatcher 530 checks the source IP address and UDP port number on each packet to determine whether the packet corresponds to a new transaction. If the packet corresponds to a new transaction, the dispatcher 530 selects the proxy server 180 with the lightest load and sends the packet to that proxy server 180. If the packet does not correspond to a new transaction (i.e. the 2.sup.nd packet of a two packet request), the dispatcher 530 looks up the proxy server 180 used for the previous packet of this transaction and sends the packet to that same proxy server 180.

Finally, the packets are received by the proxy server 180. The proxy server 180 gathers the request packets from the dispatcher 530, reassembles them into the original CTP request message, processes the request, forms a response, breaks the response down into separate IP/UDP/RMP packets, and then sends the response packets back through the TCP socket to thedispatcher 530.

The proxy server 180 receives entire IP packets imbedded in the TCP stream that the proxy server 180 receives from the dispatcher 530. These packets are re-ordered and re-assembled into the original message before the request is processed. The IP, UDP, and RMP headers are stripped off and the information in the RMP and UDP headers used to re-construct the original request message. When a response message is formed, the response message is split into separate packets as necessary. IP, UDP and RMP headers (with source and destination machine addresses and port numbers swapped) are pre-pended to the packets before they are sent via TCP to the dispatcher 530 where the packet continues its journey back to the wireless client 405.

A few important points should be noted about this wireless setup. First, the only components that are specific to the wireless network are the wireless network interface 510 on the wireless client 405, and the tunneler 430 at the proxy server 180. The wireless client 405 application software, reliable message layer 635 and all of the software on the proxy server 180 are strictly IP based and do not have to change if a different wireless network is used.

Second, the tunneler 430 and the dispatcher 530 are not required to be placed on the same physical machine as the proxy server 180. If the tunneler 430 and the dispatcher 530 are on the same machine as the proxy server 180, the LAN link between the three system elements becomes a virtual TCP connection through the IP stack on the proxy server 180. This may seem to be preferable from a performance point of view, but, there are many more advantages to having the dispatcher 530 and proxy servers 180 on separate machines. If the dispatcher 530 is on a separate machine, the dispatcher 530 can distribute wireless client 405 transactions among multiple proxy servers 180, thereby providing both scalability and fault tolerance. If any one of the proxy servers 180 become inoperative, the dispatcher 530 can stop sending requests to the inoperative proxy server 180. Because the communications system has multiple proxy servers 180 the dispatcher 530 can distribute the load between them. The dispatcher 530 therefore becomes the most sensitive link in the chain from a fault tolerance point of view. But, from a performance point of view, the dispatcher 530 has very little work to do for each transaction compared to the proxy server 180 so it makes sense to have multiple proxy servers 180 per dispatcher 530 (and tunneler 430). If necessary, multiple tunnelers 430 and dispatchers 530 can be placed in parallel to provide even more fault tolerance and scalability.

A third important point is that the only unreliable link in the whole chain is over the wireless network, i.e., between the wireless network interface 510 on the wireless client 405 and the base station 170. In particular, the link between the base station 170 and the proxy server 180 is a reliable link all the way through. The RMP logic on both the wireless client 405 and proxy server 180 is simplified because the RMP logic only corrects for lost and unordered packets over the wireless network, not the wireline network between the base station 170 and the proxy server 180. This simplified RMP logic enables the timeout values used for re-transmission attempts to be tuned for just the wireless portion of the network.

Intranet Topology

A corporate wireless Intranet is setup in the same manner as the Internet solution just described. The only major difference is the physical location of the machines. For the Internet solution, the proxy server 180 is located at the wireless network access point 410 and has a connection to the global Internet. For a corporate Intranet solution, the proxy server 180 is located at the corporation's own private site with a leased line to the nearest wireless network access point 410. The leased line transports the WLNPs between the wireless network access point 410 and the corporation's own tunneler and proxy server 180. The proxy server 180 has a direct connection to the corporation's private Intranet.

Content Layer

This section covers the implementation of the wireless communications device 100 content layer. The content layer deals with how web content and personal messages are formatted and rendered on the wireless client 405. In particular, this section discusses the Hypertext Markup Language (HTML) and Compact Markup Language (CML) page description languages.

When using the standard browser engine, the wireless client 405 web browser application renders HTML obtained directly from the web content server. When using the browser 104 however, the wireless client 405 renders CML which has been dynamically generated from HTML by the proxy server 180.

When the wireless client 405 e-mail application sends or receives personal messages with the proxy server 180, it also uses CML to format the messages. Sending and receiving graphically formatted messages is not a specified requirement of the wireless communications device 100, but CML is used for the message format because it also provides excellent raw text compression. An added benefit is that CML provides the framework required for graphically oriented messaging applications.

There are two basic challenges in the design of the browser 104. The first is effectively rendering existing web content on a very small screen. The second challenge is minimizing the amount of data that is sent over the wireless network when using the browser 104 engine.

The HTML page description language works fine for answering the first challenge, but is not an appropriate choice for answering the second challenge. HTML was designed as an "ideal" language for creating content. HTML is human readable, human editable, and screen size and depth independent. This makes it a very good general purpose page description language, but also a very verbose language and too large to transmit wirelessly.

CML answers both challenges because CML also minimizes the amount of data that is sent over the wireless network. In order to achieve its minimal size, CML sacrifices both human readability and editability.

As a further optimization, the CML is created dynamically at run-time by the proxy server 180 using knowledge of the screen size and depth of the wireless client 405. Thus, the wireless client's 405 very limited screen 101 functionality will enable the proxy server 180 to generate a much smaller CML representation than the proxy server 180 could otherwise. For example, elements that do not fit on the wireless client 405 screen 101 could be left out altogether and images that are too deep for the wireless client 405 screen 101 are depth converted before being transmitted.

Ideally, the user is not aware of whether CML or HTML is used to render content. Therefore, both page description languages provide the same feature set. However, the implementation of the two languages is significantly different because CML provides the necessary compression to accommodate the wireless network bandwidth. To accomplish these goals, CML is optimized for small wireless clients 405. However, alternate and larger forms of representation can be used to implement the full feature set of HTML when necessary.

This following provides a description CML, followed by descriptions of HTML features, how each HTML feature is displayed and used in the browser 104, and finally how that feature is represented using CML. Keep in mind that the appearance of a HTML feature is independent of whether or not it is sent to the wireless client 405 in raw HTML format or as CML.

Compact Markup Language (CML)

In order to send web content to the wireless client 405 in a minimal number of bytes, the proxy server 180 does not use the HTML standard generally used by Internet servers. In HTML, all the tags and attributes associated with text, tables, forms, etc are text based, typically take up from 3 to 10 bytes each, and are stored both at the beginning and end of the text that they modify. For example, to display emphasized text, a web document would have to contain the following HTML sequence: <STRONG> This is emphasized text</STRONG>.

The wireless client 405 and the proxy server 180 use a special format for transferring screen 101 contents from the proxy server 180 to the wireless client 405. This format, named Compact Markup Language (CML), emphasizes compactness over readability and generally uses variable length binary bit fields instead of text to represent options and formatting information. The differences do not end there however; CML will use a host of other methods for reducing the number of bytes that is sent between the proxy server 180 and the wireless client 405.

CML compresses all text. In one embodiment, the default CML compression scheme formats text using a form of a five-bit character alphabet with escapes. This default compression scheme works best with pages that have mainly lower case alpha letters in them, but does allow for a full range of characters including characters with ASCII values greater than 128.

CML also leverages the fact that the proxy server 180 knows the screen size and bit depth of the wireless client 405 when encoding the layout of the content. HTML was designed to be screen independent--neither the server nor the content creator knows ahead of time what size or depth screen upon which the document will eventually be rendered. Besides the obvious advantage of not sending content that wouldn't fit on the wireless client 405 screen 101, there are other cases where content can be encoded in a more compact form by the proxy server 180 because it knows the size of the wireless client 405 screen 101. Since the proxy server 180 also knows the bit depth of the wireless client 405, the proxy server 180 can also reduce the data sent to the wireless client 405 by not sending color attributes such as the background color, text colors, underline colors, etc.

The major emphasis of CML is that it is optimized for size. In other words, readability and flexibility are compromised for compactness. One major design philosophy difference between HTIML and CML is that CML is not designed as a content creation language. CML is merely a temporary format used to represent content as it is being transferred between a proxy server 180 and a wireless client 405. As such, CML is algorithmically generated, much like object code is generated from a compiler. The analogy to compilers is even stronger when you take into account the fact that CML is generated with the screen size and attributes of the wireless client 405 taken into account. The same HTML content can produce different CML representations for two wireless clients 405 that have different screen sizes--much like compilers for different microprocessor produce different object code from the same source code.

Essentially, CML is a stream of text and image data with imbedded formatting commands (tags). The tags are imbedded as binary data and hence are very compact. Every tag is "sticky"; that is the tag continues to have an effect until explicitly changed by another tag of the same type. For example, a tag in the front of a document that specifies bold text makes the entire document bold, unless another tag later in the document turns off the bold formatting. This is in contrast with many HTML tags, such as paragraph formatting commands, that only affect the next paragraph.

Another important difference between CML and HTML is that white space and line breaks in the text are significant. For CML, the equivalent of the HTML line break tag (<BR>) is not required in CML since line breaks are imbedded directly into the text.

The default behavior of CML is to compress all text by encoding it using a special 5-bit character alphabet discussed below in the CML Structure section. This form of compression works best for documents that are mainly comprised of lower case roman characters. Other forms of text encoding, including 8 bit ASCII, unicode, etc. are used in CML only when necessary.

Using CML and the CML structure described below combined with CTP formatting of forms, some embodiments of the invention comprise a method for transmitting a message from a wireless client 405 to a proxy server 180. The method comprises transmitting a single message from the wireless client 405 to the proxy server 180. The single message comprises a single packet of data. The single packet of data having a base document uniform resource locator followed by compressed data. The compressed data comprises references to fields in a hyperlink document and an indication of use of the hyperlink document. The hyperlink document is in the base document. In some embodiments, the size of the single packet of data is less than one kilobyte.

In some embodiments, the references to fields comprise field values and field indices corresponding to fields in the hyperlink document. In some embodiments, the base uniform resource locator is expressed in a compact transfer protocol by a binary string. The binary string comprises a first field indicating the encoding scheme used for the single message.

Compact Data Structure Notation

Throughout the rest of this application, CML will be represented using a notation similar to that used in the C language for representing data structures. This notation will be called Compact Data Structure Notation (CDSN) and is also used later in this document when describing the CTP protocol. An example of this notation is:

                  Bit               enabled=1
                  Bit[3]            type=typeRound
                  Int16             length=0x1234

                      1 010 0001001000110100

          Bit               - a single bit
          UInt8, Int8       - 8 bit unsigned and signed integers
          UInt16, Int16     - 16 bit unsigned and signed integers
          UInt32, Int32     - 32 bit unsigned and signed integers

    UIntV:
    0               - The value 0
    10      Bit[3]  - The values 0 through 7 (0x07)
    110     Bit[6]  - The values 0 through 63 (0x3F)
    1110    Bit[16] - The values 0 through 65535 (0xFFFF)
    1111    Bit[32] - The values 0 through 4,294,967,295 (0xFFFFFFF)
    IntV:
    0               - The value 0
    0       Bit[3]  - The values -4 through 3
    110     Bit[6]  - The values -32 through 31
    1110    Bit[16] - The values -32768 through 32767
    1111    Bit[32] - The values -2,147,483,648 through 2,147,483,647

                        5-bit Characters:
    Value Special Reset Description
    0     Yes     Yes   EndTag character. Used to terminate multi-
                        parameter tags and block elements
    1     Yes     Yes   StartTag character, followed by 8 or 16 bit Tag
                        ID.
    2     Yes     No    Single character escape
    3     No      No    Reserved
    4     No      No    Line break
    5     No      No    Space character
    6-31  No      No    The lowercase letters: `a` through `z`

              Bit[5]          char=6          //`a`
              Bit[5]          char=7          //`b`
              Bit[5]          char=8          //`c`
              Bit[5]          char=5          //` `
              Bit[5]          char=9          //`d`
              Bit[5]          char=4          //linebreak
              Bit[5]          char=10         //`e`
              Bit[5]          char=11         //`f`

                          00110 00111 01000 00101 01001 00100
          01010 01011

          Bit[5]      char=6        //`a`
          Bit[5]      char=5        //` `
          Bit[5]      char=2        //single character escape
          Bit[8]      char=67       //`C`
          Bit[5]      char=20       //`o`
          Bit[5]      char=28       //`w`

        Bit[5]    char=6            //`a`
        Bit[5]    char=5            //` `
        Bit[5]    char=1            //tag escape character
        Bit[8]    tagID=textBold    //constant value for textBold
        Bit[5]    char=8            //`c`
        Bit[5]    char=20           //`o`
        Bit[5]    char=28           //`w`

    Bit[5]  char=6        //`a`
    Bit[5]  char=5        //` `
    Bit[5]  char=1        //tag escape character
    Bit[8]  tagID=textSize //constant value for textSize
    UIntV   size=4        //the value 4, as a UIntV is // 5 bits long: 10100
    Bit[5]  char=9        //`d`
    Bit[5]  char=20       //`o`
    Bit[5]  char=12       //`g`

    Bit[5]  char=6                 //`a`
    Bit[5]  char=5                 //` `
    Bit[5]  char=1                 //tag escape character
    Bit[8]  tagID=textEncoding8Bit
    Bit[8]  char=`B`               //`B`
    Bit[8]  char=``I`              //`I`
    Bit[8]  char=``G`              //`G`
    Bit[8]  char=0                 //endTag, switches text encoding
                                   //back to 5-bit mode
    Bit[5]  char=9                 //`d`
    Bit[5]  char=20                //`o`
    Bit[5]  char=12                //`g`

                  Tag                tagID:
                  Char               startTag=1
                  Bit                longTag
                  if                 (longTag==0)
                  Bit[7]             tagID
                  else
                  Bit[15]            tagID

            Tag         tag=smallTag         //smallTag=5

                         00001 0 0000101

            Tag         tag=bigTag         //bigTag=512

                     00001 1 000001000000000

        Tag       tag=textEncoding8Bit   //textEncoding8Bit=6
        Bit[8]    char =`A`              //0x41
        Tag       tag=smallTag           //smallTag=5
        Bit[5]    char=6                 //`a`

    00001   0             0000110   01000001  00000001          0 0000101
    tag Esc textEncoding  8Bit      'A'       tagEsc     smallTag    'a'

    Bit[5]  char=6                   //`a`
    Bit[5]  char=5                   //` `
    Bit[5]  char=1                   //tag escape character
    Bit[8]  tagID=textEncoding8Bit
    Bit[8]  char=`B`                 //`B`
    Bit[8]  char=`I`                 //`I`
    Bit[8]  char=`G`                 //`G`
    Bit[8]  char=0                   //endTag character
                                     //switches back to 5-bit mode
    Bit[5]  char=9                   //`d`
    Bit[5]  char=20                  //`o`
    Bit[5]  char=12                  //`g`

                Text               string="a BIG dog"

          Bit[5]    char=6             //`a`
          Bit[5]    char=5             //` `
          Bit[5]    char=1             //tag escape character
          Bit[8]    tagID=textBold     //constant value for
                                       textBold
          Bit[5]    char=8             //`c`
          Bit[5]    char=20            //`o`
          Bit[5]    char=28            //`w`

                  Text                 string="a"
                  Tag                  tag=textBold
                  Text                 string="cow"

                           TextZ text:
                  Text                 text
                  Char                 end=endTag

                  Tag                  tag=tagMeta
                  TextZ                name
                  TextZ                value

                Parameters:
                Byte                 red
                Byte                 green
                Byte                 blue
                Examples:
                Tag                  tag=tagBGColor
                Byte                 red=0xFF
                Byte                 green=0x80
                Byte                 blue=0x80

        Parameters:
        Image         img         //[still need to define image format]
        Examples:
        Tag           tag=tagBGImage
        Image         img=...     //[still need to define image format]

              Parameters:
              Byte                   red
              Byte                   green
              Byte                   blue
              Examples:
              Tag                    tag=tagTextColor
              Byte                   red=0xFF
              Byte                   green=0x80
              Byte                   blue=0x80
              Text                   "This text is reddish"

        Parameters:
        Bit             visited
        Byte            red
        Byte            green
        Byte            blue
        Examples:
        Tag             tag=tagLinkColor
        Bit             visited=1          //set color for visited
        //links
        Byte            red=0xFF
        Byte            green=0x80
        Byte            blue=0x80

                Parameters:
                Byte                 red
                Byte                 green
                Byte                 blue
                Examples:
                Tag                  tag=tagTextColor
                Byte                 red=0xFF
                Byte                 green=0x80
                Byte                 blue=0x80
                Text                 "This text is reddish"

        Parameters:
        Bit               relative//relative or absolute size
        UIntV             size      //line height of text in pixels.
        Examples:
        Tag               tag=tagTextSize
        Bit               relative=0
        UIntV             size=9

              Parameters:
              None
              Examples:
              //Start bold text
              Tag                      tag=tagTextBold
              Text                     "This is bold text"
              //End bold text
              Char                     end=endTag

              Parameters:
              None
              Examples:
              //Start italic text
              Tag                      tag=tagTextItalic
              Text                     "This is italic text"
              //End italic text
              Char                     end=endTag

            Parameters:
            None
            Examples:
            //Start underlined text
            Tag                      tag=tagTextUnderline
            Text                     "This is underlined text"
            //End underlined text
            Char                     end=endTag

    Parameters:
    Bit[4]      format                 //one of monoSpaced, strike,
    //bigger, smaller, sub, sup,
    //definition, code, sample,
    //keyboard, variable, cite
    Examples:
    Tag         tag=tagTextFormat
    Bit[4]      format=code
    Text        "itemP=itemP->nextItemP,"

          Parameters:
          None
          Examples:
          Tag               tag=tag8BitEncoding
          Text              "THIS IS 8-BIT ENCODED TEXT"
          //End 8-bit encoded text
          Char              end=endTag

        Parameters:
        Bit[3]          align     //one of alignLeft, alignCenter,
        //alignRight
        Examples:
        Tag             tag=tagH1
        Bit[3]          align=alignCenter
        Text            "This is a Heading"
        Char            endTag    //end heading tag

                Parameters:
                TextZ                name
                TextZ                content
                Examples:
                Tag                  tag=tagMeta
                TextZ                "History"
                TextZ                "Quote Results"

              Parameters:
              UIntV                dateHi
              UIntV                dateLo
              Examples:
              Tag                  tag=tagDatePicker
              UIntV                dateHi=0
              UIntV                dateLo=0xA1234000

        Parameters:
        UIntV                seconds
        Examples:
        Tag                  tag=tagTimePicker
        UIntV                seconds=3600         //1:00 am.
        Paragraph Attributes

        Parameters:
        Bit[3]        align     //one of alignCenter, alignLeft, or
        //alignRight.
        Examples:
        //Turn on center alignment
        Tag           tag=tagParagraphAlign
        Bit[3]        align=alignCenter
        Text          ".backslash.n This paragraph is centered."
        //Turn off left alignment
        Tag           tag=tagParagraphAlign
        Bit[3]        align=alignLeft
        Text          ".backslash.n This paragraph is left aligned."

        Parameters:
        UIntV             indent      //number of pixels to indent
        Examples:
        //Indent the next paragraph by 10 pixels
        Tag               tag=tagMarginIndent
        UIntV             indent=10
        Text              ".backslash.n This text is indented."
        //Restore indent
        Tag               tag=tagMarginIndent
        UIntV             indent=0

    Parameters:
    None
    Examples:
    Tag             tag=tagBlockQuote
    Text            "The whole problem with the world is that fools and
    fanatics are always so certain of themselves, but
    wiser people so full of doubts."
    Text            "-Bertrand Russell"
    Lists

          Parameters:
          Bit[3]  type // one of listT1, listTa, listTA,
          // listTi, or listTI
          UIntV   start // starting sequence number minus 1
          Bit     compact // compact spacing between items
          Examples:
          // The list header
          Tag     tag = tagListOrdered
          Bit[3]  type = listT1
          UIntV   start = 0
          Bit     compact = 0
          // The list items.
          Text    "First item"
          Char    itemSeparator = endTag
          Text    "Second item"
          // ------------- // itemSeparator not used here
          Tag     tag = tagListItemCustom
          Bit[3]  type = listTa
          UIntV   value = 4
          Text    "Third item"
          Char    end = endTag // end of 3rd item
          // The end of the list
          Char    end = endTag// end of list

          Parameters:
          Bit[3]  type  // one oflistTDisk, listTSquare, or
          // listTCircle
          Bit compact // compact spacing between items
          Examples:
          // The list header
          Tag     tag = tagListUnordered
          Bit[3]  type = listTDisk
          Bit     compact = 0
          // The list items.
          Text    "First item"
          Char    itemSeparator = endTag
          Text    "Second item"
          // ------------- // itemSeparator not used here
          Tag     tag = tagListItemCustom
          Bit[3]  type = listTSquare
          UIntV   value = 0
          Text    "Third item"
          Char    itemSeparator = endTag // end of 3rd item
          // The end of the list
          Char    endList = endTag

          Parameters:
          Bit[3]  type  // The bullet or number style
          UIntV   value // ignored for unordered lists.
          Examples:
          Tag     tag = tagListItemCustom
          Bit[3]  type = listTSquare
          UIntV   value = 0
          Text    "Third item"
          Char    itemSeparator = endTag

          Parameters:
          None
          Examples:
          Tag     tag = tagListItemDefinition
          Text    "This is the definition of the first item"
          Forms

          Parameters:
          UIntV formIndex // assigned by proxy server
          Bit         standalone
          if (standalone)
          Bit     post    // if 1, use POST instead of GET
          TextZ action    // URL of the CGI-script
          else
          Bit     secure  // true if URL is HTTPS scheme
          Examples:
          Tag     tag = tagForm
          UIntV   formIndex = 0
          Bit         standalone = 1
          Bit         post = 0
          TextZ       action = "http://www.server.com/cgi-bin/submit"
          // The form input items
          Text    "Age 0-12:"
          Tag tag =   tagInputRadio
          Bit checked = 0
          UIntV       group = 0
          Bit         hasName = 1
          Bit         hasValue = 1
          TextZ       name = "age"
          TextZ       value = "0-12"
          Text    "Age 13-17:"
          Tag tag =   tagInputRadio
          Bit checked = 1
          UIntV group = 0
          Bit         hasName = 1
          Bit         hasValue = 1
          TextZ       name = "age"
          TextZ value = "13-17"
          Tag tag =   tagInputSubmit
          Bit         hasName = 0
          Bit         hasValue = 1
          TextZ       value = "OK"
          Char    endForm = endTag

          Parameters:
          Bit checked
          UIntV       group
          Bit         hasName
          Bit         hasValue
          if (hasName)
          TextZ name
          if (hasValue)
            TextZ value
          Examples:
          Tag     tag = tagInputRadio
          Bit     checked = 0
          UIntV   group = 0
          Bit     hasName = 1
          Bit     hasValue = 1
          TextZ   name = "age"
          TextZ   value = "13-17"
          Text    "Age 13-17"

          Parameters:
          Bit     checked
          Bit         hasName
          Bit         hasValue
          if (hasName)
          TextZ         name
          if (hasValue)
          TextZ         value
          Examples:
          Tag     tag = tagForm
          Tag     tag = tagInputCheckbox
          Bit     checked = 0
          Bit     hasName = 0
          Bit     hasValue = 0

          Parameters:
          UIntV size  // visible width of field in
          // characters
          UIntV maxLength // maximum number of allowed
          // characters
          Bit         hasName
          Bit         hasValue
          if (hasName)
            TextZ name
          if (hasValue)
          TextZ value
          Examples:
          Tag     tag = tagForm
          Text    "Enter Name:"
          Tag tag =   tagInputTextLine
          UIntV       size = 20
          UIntV       maXLength = 0
          Bit         hasName = 0
          Bit         hasValue = 1
          TextZ       value = "your name here . . . "

          Parameters:
          UIntV rows  // number of rows
          UIntV cols  // number of columns
          Bit         hasName
          Bit         hasValue
          if (hasName)
            TextZ name
          if (hasValue)
            TextZ value
          Examples:
          Text    "Enter Address:"
          Tag tag = tagInputTextArea
          UIntV   rows = 2
          UIntV   cols = 20
          Bit     hasName = 1
          Bit     hasValue = 1
          TextZ   name = "address"
          TextZ   value = "your address here . . . "

          Parameters:
          UIntV size  // visible width of field in
                      // characters
          UIntV maxLength // maximum number of allowed
                          // characters
          Bit     hasName
          Bit     hasValue
          if (hasName)
            TextZ name
          if (hasValue)
            TextZvalue
          Examples:
          Text    "Enter Password:"
          Tag     tag = tagInputPassword
          UIntV   size = 20
          UIntV   maxLength = 0
          Bit     hasName = 0
          Bit     hasValue = 0

          Parameters:
          Bit