Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L67/00—Network arrangements or protocols for supporting network services or applications
  • H04L67/01—Protocols
  • H04L67/04—Protocols specially adapted for terminals or networks with limited capabilities; specially adapted for terminal portability
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
  • G06F16/90—Details of database functions independent of the retrieved data types
  • G06F16/95—Retrieval from the web
  • G06F16/957—Browsing optimisation, e.g. caching or content distillation
  • G06F16/9577—Optimising the visualization of content, e.g. distillation of HTML documents
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L67/00—Network arrangements or protocols for supporting network services or applications
  • H04L67/50—Network services
  • H04L67/56—Provisioning of proxy services
  • H04L67/565—Conversion or adaptation of application format or content
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L67/00—Network arrangements or protocols for supporting network services or applications
  • H04L67/50—Network services
  • H04L67/56—Provisioning of proxy services
  • H04L67/565—Conversion or adaptation of application format or content
  • H04L67/5651—Reducing the amount or size of exchanged application data
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W28/00—Network traffic management; Network resource management
  • H04W28/02—Traffic management, e.g. flow control or congestion control
  • H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
  • H04W4/18—Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals

Definitions

• This invention relates to the field of information communications.
• the invention relates to low bandwidth network access to Internet based information.
• Wireless communications provides one method for mobile users to communicate to a wired network.
• 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 MobitexTM system).
• the method in which they access the information is highly dependent on the type of wireless communications available to the user.
• a high bandwidth network such as a wired network or a satellite system
• the usual techniques for browsing data on the Internet are adequate.
• Web World Wide Web
• the URL represents the address of the entry point to the web site (e.g., the home page for the web site).
• 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.
• HTTP HyperText Transport Protocol
• 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.
• 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.
• 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.
• low bandwidth networks 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 daunting obstacle for packet data network customer use.
• 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 PalmPilotTM handheld device available from 3COM Corporation, Inc. of Santa Clara, California. Examples of the function set supported are address books, calendars, and task lists.
• wireless communications with handheld devices have been performed using wireless modems, such as are available from Novatel
• 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.
• handheld devices 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.
• 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.
• the Netscape CommunicatorTM browser application caches web pages on the client. Each cached web page is associated with a URL.
• 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 NetAttacheTM, available from Tympany, Inc. of Mountain View, CA.
• 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.
• 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.
• One embodiment of the invention includes a system having a distributed web site.
• the web site is distributed between a client, a server and a web server.
• the client stores a set of predefined applications that correspond to a part of the web site.
• the applications include data formatted according to a first markup language.
• the server receives the queries and generates new, related queries.
• the new queries correspond to a second query protocol.
• the second query protocol is used by the web server.
• the web server generates responses to the new queries and sends these responses to the server.
• the responses are formatted according to a second markup language. These responses correspond to the second portion of the web site.
• the server then converts the responses into new responses that the client can use.
• the client includes a handheld computer that has wireless communications capabilities at least a part of the communications between the client and the server is done wirelessly.
• the client includes a browser application that interfaces with the applications in the set of applications.
• the browser application is also executed.
• the browser application is responsible for rendering the data in the first markup language, initiating queries, and rendering responses.
• the data in the applications correspond to a number of hyper-linked markup pages. At least some of the hyper-linked markup pages include data for generating the query.
• the hyper-linked markup pages correspond to a part of a web tree.
• Each of the applications can therefore correspond to a part of a corresponding web tree of a corresponding web site being served by a corresponding web server.
• the client includes additional applications. These additional applications can include data formatted according to the first markup language and/or they can be stand alone applications that otherwise interface with the browser application to generate queries.
• the second markup language is HTML (HyperText Markup Language) and the first markup language is a compressed version of at least part of HTML.
• the queries from the client to the server are sent according to a first protocol.
• the queries from the server to the web server are sent according to a second protocol.
• the second protocol includes HTTP (HyperText Transport Protocol) and the first protocol corresponds to a compressed version of HTTP.
• Figure 1 illustrates a wireless communications device communicating with a web server.
• Figure 2 illustrates a method of communicating between a wireless communications device and a web server.
• Figure 3 illustrates an example user interface for a wireless communications device.
• Figure 4 illustrates a wireless network topology.
• Figure 5 illustrates a wireless network topology including a wireless network interface, a wireless network leased line, and a dispatcher.
• Figure 6 illustrates an example of a wireless communications device exchanging messages in a communications system.
• Figure 7 illustrates a reliable message protocol packet structure.
• Figure 8 illustrates an exchange of a single request packet and a single response packet using the reliable message protocol.
• Figure 9 illustrates an exchange of messages comprising a single request packet and two response packets using the reliable message protocol.
• Figure 10 illustrates an exchange of messages including a retransmit sequence using the reliable message protocol.
• Figure 11 illustrates lower level communication layers.
• Figure 12 illustrates the format of data passed between wireless client software layers.
• Figure 13 illustrates the format of an IP header and a UDP header.
• Figure 14 illustrates an alternative system for communicating between a wireless communications device and a web server.
• Example Method of Communicating Between a Wireless Communications Device and a Web Server 23 Example User Interface 25
• HTML Element Functionality 73 The Head Elements 73
• the RMP Data Area 152 The RMP Data Area 152
• the wireless communications device 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.
• 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.
• 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.
• a second goal of the invention is wireless messaging.
• 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.
• 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 -> proxy server) and one packet down (proxy server ->wireless client) over the wireless network.
• 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.
• CTP compact transfer protocol
• 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.
• 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 handheld device examples include the Palm IIITM handheld computer and Microsoft's palm sized computers.
• 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® 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.
• Figure 1 illustrates a wireless communications device communicating with a web server.
• 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.
• Figure 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.
• Figure 1 also includes a number of arrows indicating queries and responses.
• 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 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).
• the wireless communications device 100 includes a Palm IIITM compatible handheld device having wireless communications capabilities.
• the wireless communications device 100 is for communicating over the BellSouth Mobile Data (BSMD) Mobitex system.
• BSMD BellSouth Mobile Data
• Other embodiments of the invention support other wireless communications networks.
• the BSMD BellSouth Mobile Data
• 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 OSTM operating system available from the 3COM Corporation, of Santa Clara, California.
• 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.
• 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 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.
• 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 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 HTML 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
• 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.
• 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.
• the proxy server 180 can converts image content to a size and bit depth appropriate for display on the wireless communications device 100.
• 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.
• 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.
• 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.
• CTP compressed transport protocol
• 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.
• a one packet response is returned to the wireless communications device 100.
• 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.
• 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.
• 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.
• 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.
• 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 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.
• wireline links 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 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.
• this layout and size are the only differences between content rendered for a wireless communications device 100 and existing desktops.
• 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.
• 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.
• 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 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.
• the browser 104 sends a request out over the network to fetch the airline information.
• the proxy server 180 three to five seconds later
• the browser 104 there are a number of significant differences between the browser 104 and a standard web browser.
• the browser 104 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.
• 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.
• the proxy server 180 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.
• CGI Common Gateway Interface
• 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.
• 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 URL).
• Figure 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 Figure 1.
• the example method of Figure 2 can be broken into three processes: a build a distributed web site process 202, a query process 204, and a response process 206.
• 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.
• 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.
• 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.
• a user loads the wireless application 106 onto the wireless communications device 100.
• This can be done as a HotSyncTM 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.
• this second method of loading the wireless application 106 is less desirable in that it will require a significant amount of bandwidth.
• 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).
• 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.
• the building of the distributed web site process 202 has been described.
• the query process 204 includes the following steps.
• the user fills in a query form 105 as part of the wireless application 106.
• the user is filling out a form to find Italian restaurants in San
• 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.
• 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.
• the query process 204 is completed.
• the web server 140 generates and sends an HTML page 144 to the proxy server 180.
• the web server 140 generates the HTTP response 136 in response to the HTTP query 126.
• 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.
• 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.
• the proxy server 180 may initiate multiple requests depending on the response in block 260. Note however, only one CTP request was needed.
• 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.
• the browser 104 can display the example query response 107 on the screen 101.
• Figure 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.
• 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.
• the user has selected "fine food" from the launcher interface 303.
• 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.
• 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 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.
• a toolbar 310 is also presented on the screen 101.
• 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.
• Figure 1 and Figure 4 show the general topology of a wireless communications network.
• the wireless client 405 in Figure 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.
• Figure 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.
• 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.
• 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.
• 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).
• WLNP wireless network protocol packet
• 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.
• RQMF/RSMF Request/Response Message Fragment
• 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.
• 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.
• 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.
• 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.
• 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 Figure 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.
• Figure 5 illustrates the wireless network topology including a wireless network interface 510, a wireless network leased line 520, and a dispatcher 530.
• Figure 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.
• wireline LAN Local Area Network
• 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 Figure 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.
• Figure 5 shows the wireless network interface 510 adding a
• the 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.
• Figure 5 shows only one tunneler 430, two tunnelers are typically used for the wireless packet data network.
• 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.
• 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 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
• 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 the dispatcher 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.
• the wireless network interface 510 on the wireless client 405, and the tunneler 430 at the proxy server 180 are the wireless client 405 application software, reliable message layer 635 and all of the software on the proxy server 180.
• 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.
• 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.
• the link between the base station 170 and the proxy server 180 is a reliable link all the way through.
• 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.
• 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.
• the proxy server 180 is located at the wireless network access point 410 and has a connection to the global Internet.
• 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.
• the content layer deals with how web content and personal messages are formatted and rendered on the wireless client 405.
• this section discusses the Hypertext Markup Language (HTML) and Compact Markup Language (CML) page description languages.
• HTML Hypertext Markup Language
• CML Compact Markup Language
• the wireless client 405 web browser application When using the standard browser engine, the wireless client 405 web browser application renders HTML obtained directly from the web content server.
• the wireless client 405 When using the browser 104 however, the wireless client 405 renders CML which has been dynamically generated from HTML by the proxy server 180.
• the wireless client 405 e-mail application 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.
• 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.
• 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.
• HTML features how each HTML feature is displayed and used in the browser 104, and finally how that feature is represented using CML.
• CML Compact Markup Language
• the proxy server 180 does not use the HTML standard generally used by Internet servers.
• HTML 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.
• 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
• CML Compact Markup Language
• 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.
• 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.
• CML 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 HTML 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.
• 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.
• CML is a stream of text and image data with imbedded formatting commands (tags).
• 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.
• CML 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.
• 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.
• the size of the single packet of data is less than one kilobyte.
• the references to fields comprise field values and field indices corresponding to fields in the hyperlink document.
• 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.
• 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.
• CDSN Compact Data Structure Notation
• the first field, enabled, is a 1 bit field that has the value 1.
• the second field, type is a 3 bit field that has the value typeRound which is a constant defined to be 2.
• the third field, length is a 16 bit integer with the value 0x1234. Fields in CDSN are never padded to fall on word, or even byte boundaries.
• each field starts off on the next free bit after the previous field. All multi- bit values are stored most-significant-bit first.
• CDSN A number of primitive data types are used in CDSN. The basic ones are:
• UInt32, Int32 - 32 bit unsigned and signed integers Other important types are the unsigned and signed variable length integer types: UlntV and IntV. These can be anywhere from 1 to 36 bits in length, depending on their value. The actual length can be determined by looking at the first 1 to 4 bits.
• a CML data stream is by default a 5-bit character text stream. Until a special character (as discussed below) appears in the stream, each sequence of 5 bits is assumed to represent a single text character.
• the following table lists the possible 5-bit characters:
• the single character escape (2) is followed by an 8 bit ASCII character.
• This single character escape then can be used to represent characters that are not present in the 5 bit alphabet.
• the text: a Cow is represented in CML as the following sequence:
• 67 is the 8 bit sequence 01000011 which represents the ASCII value for 'C (67 decimal, 0x43 hexadecimal) and all other characters are 5 bits long.
• the tag start character (1) is included in a CML stream to indicate the presence of a CML tag.
• the tag start character is followed by an 8 or 16 bit Tag ID structure.
• the 8 or 16 bit Tag ID structure can be optionally followed by other variable length bit fields, depending on the specific tag.
• the 8-bit Tag ID structures have the first bit clear and can have the values 0 through 127 (0 through 0x7F hexadecimal).
• the 16-bit Tag ID structures have the first bit set and can have the values 32768 through 65535 (0x8000 through OxFFFF hexadecimal).
• tags have different functions. Some tags are followed by other variable length bit fields which specify parameters for that particular tag function. Other tags have no parameters at all. In any case, because the tag start character is a reset character, the text encoding mode is set back to 5-bit characters whenever a tag is encountered (unless the tag specifically changes the text encoding mode).
• the Tag textBold is used to turn on bold formatting. It has no parameters.
• a d ⁇ g would be represented in CML as:
• CML tags are used to include strings of text that can not be encoded as 5-bit characters.
• text encoding tags are merely tags that have a variable number of parameters following them, where each "parameter” is another character in the text stream. The sequence of "parameters” ends as soon as a reset character is encountered (the endTag or startTag character).
• the textEncoding ⁇ Bit tag indicates a string of 8 bit characters follows.
• the string of 8 bit characters is assumed to continue in the stream until a reset character is encountered.
• all special characters (which includes the reset characters and single character escape) are also now 8 bits long.
• the endTag character becomes the 8 bit sequence ObOOOOOOOO
• the startTag character becomes the 8 bit sequence ObOOOOOOOl.
• the single character escape (3 decimal) can be used to include characters in the text which are normally special characters.
• a 16-bit Unicode character of decimal value 1 could be included in the stream by inserting the 16-bit single character escape (3 decimal) in front of it.
• endTag character is sometimes used in CML to separate two elements or to indicate the end of a block level element.
• the list items are separated from each other by the endTag.
• the endTag For example, when a list needs to be represented in CML, the list items are separated from each other by the endTag.
• a 5 -bit endTag character would be placed in the stream.
• Tag ID structure Because the sequence of the tag escape character followed by Tag ID structure is used so often in the documentation, it is given it's own data type. It is defined as:
• startTag character (decimal 1) followed by a single bit specifying the length of the tagID, followed by either a 7 or 15 bit tagID.
• tag escape character is normally 5 bits long, except when an alternate text encoding mode is in effect, in which case it's length depends on the particular text encoding mode.
• Text data type Another common data type used in CML is the Text data type. This type is used to conveniently represent a string of characters. This type is a very powerful data type because it hides the complexity of escaping special characters and the actual number of bits required to represent each character.
• the Text data type hides the complexities of escaping non-lower case alpha characters as well as the endTag character used to switch the mode back from 8-bit to 5-bit ASCII.
• this sequence can be rep ⁇
• TextZ is basically a Text type with a terminating endTag character. This type is most often used in tag parameter lists. It can be defined simply as:
• the format of the meta tag is defined as:
• variable is defined as a TextZ type, the variable generally has an endTag character at the end of it, though the end could be implied by the presence of a following tag.
• This section lists the various CML tags available. Each tag is described in detail along with its parameters, if any. This section refers to tags by name, but in the actual implementation a pre-defined constant is associated with each tag.
• Tag tag tagBGColor
• This image will be tiled to fill the entire window.
• Tag tag tagBGImage
• Tag tag tagLinkColor
• Bit visited 1 // set color for visited
• Tag tag tagTextBold Text "This is bold text"
• Tag tag tagTextltalic
• Tag tag tagHl
• Tag tag tagMeta TextZ "History” TextZ "Quote Results”
• time value Used to specify a time value. It takes either a valid time, or if 0 is specified, the current time is assumed. The time is specified as the number of seconds since midnight.
• Tag tag tagTimePicker
• Bit[3] align // one of alignCenter, alignLeft, or // alignRight.
• Tag tag tagParagraphAlign
• the indent parameter specifies the number of pixels to indent on both the left and right margins of the window. The indenting takes effect on the next line of text, whether due to word wrap or line break.
• Tag tag tagMarginlndent
• Tag tag tagBlockQuote
• Each item in the list is ended either by a endTag character or a tagListltemCustom tag with parameters.
• the end of the list is indicated by the endTag character.
• Bit[3] type // one oflistTl, listTa, listTA, // listTi, or listTI
• Each item in the list is ended either by a endTag character or a tagListltemCustom tag with parameters.
• the end of the list is indicated by the endTag character.
• Bit[3] type // one oflistTDisk, listTSquare, or
• Bit[3] type // The bullet or number style
• Tag tag tagListltemDefinition
• a form encloses one or more input items and ends with an endTag character.
• a standalone form is indicated by a 1 in the standalone attribute of the form tag.
• a 1 in this bit indicates that the form also has post and action attributes and that each of it's input fields have the necessary attributes (name and value) for submitting the form without making the proxy reference the original HTML form off the internet first.
• the encoding normal form submissions section below describes how to submit a standalone form to the proxy server 180.
• a server dependent form is indicated by a 0 in the standalone attribute.
• a 0 in this bit indicates that the form does not have post or action attributes and that it's input fields do not have associated name or value attributes.
• the form Index is assigned by the proxy and starts at 0 for the first form in a document.
• the post attribute is 0 if the form should be submitted to the CGI script using the HTTP GET method or 1 if the form should be submitted using the HTTP POST method. Currently, only the GET method is supported.
• the action attribute contains the URL of the CGI script on the server that handles the form submission.
• the secure bit is only present for server-dependent forms
• the secure bit is set if the action URL for the form is for a secure site (i.e. uses the HTTPS scheme).
• the secure bit is used by the wireless client 405 to determine if the wireless client 405 should send the form submission to the proxy server 180 encrypted or not.
• the wireless client 405 checks the scheme that is in the action URL parameter to see if the submission should be encrypted or not.
• TextZ action // URL of the CGI-script else Bit secure // true if URL is HTTPS scheme
• the checked parameter indicates the initial state of the control.
• the group parameter is assigned by the proxy server 180 and allows the wireless client 405 to perform mutual exclusion selecting.
• the hasName and hasValue are normally only set in standalone forms and indicate the presence of following text fields that contain the control's name and value.
• the checked parameter indicates the initial state of the control.
• the hasName and hasValue parameters are normally only set in standalone forms and indicate the presence of following text fields that contain the control name and value. Parameters:
• a maxLength parameter of 0 means no limit on the number of characters entered.
• the hasName parameter is normally only set in standalone forms.
• the hasValue parameter may be set in either type of form and indicates the initial default text for the input item.
• the hasName parameter is normally only set in standalone forms.
• the hasValue parameter may be set in either type of form and indicates the initial default text for the input item.
• Tag tag taglnputTextArea
• a maxLength parameter of 0 means no limit on the number of characters entered.
• the hasName and hasValue parameters are normally only set in standalone forms and indicate the presence of following text fields that contain the field's name and value.
• the label parameter is the button's label.
• An endTag character marks the end of the label.
• the hasName parameter is normally only set in standalone forms.
• the hasValue parameter may be set in either type of form and indicates the text that should appear inside the button. If the hasValue parameter is omitted, the default text of "submit" will be placed in the button.
• the hasValue parameter may be set to indicate the text that should appear inside the button. If the hasValue parameter is omitted, the default text of "reset" will be placed in the button.
• Tag tag taglnputReset
• the multiple parameter should be set if multiple items are allowed to be selected at once. If multiple is set, then the size parameter indicates how many visible choices appear at once in the menu.
• the hasName parameters is normally only set in standalone forms.
• This element is followed by 1 or more Text elements representing the menu options that are separated by endTag characters or tagSelectltemCustom tags.
• the tagSelectltemCustom tag only needs to be used for pre-selected items.
• An additional endTag character follows the last item and indicates the end of the select menu.
• Tag tag taglnputSelect
• the hasValue parameter is normally only set in standalone forms. It can be used to indicate the text that should be included as the value of this item during the form submission. If this parameter is omitted, then the text that follows the tagSelectltemCustom tag is used instead.
• Tag tag tagSelectltemCustom
• the width parameter Used to mark the start of a table. If the width parameter is 0, the width of the table will be calculated from the contents.
• the border parameter can be 0 to suppress the border. If cellspacing is non-zero, then borders will be draw around every cell. The cellPadding sets the padding in pixels between the border around each cell and the cell's contents - default is 0.
• Each row in the table starts out with a tagTableRow tag that has optional parameters for the horizontal and vertical alignment of the cells in that row.
• the cells within a table row are separated by endTag' s, or tagTableColumn tags.
• the tagTableColumn tags mark header cells, or permit attributes to be set for the next cell.
• the first cell in each row can have a tagTableColumn tag preceding it if necessary in order to change its attributes.
• Each row in the table starts out with a tagTableRow tag that has optional parameters for the horizontal and vertical alignment of the cells in that row.
• tagTableColumn tags denote whether the next cell is a header cell or a data cell.
• tagTableColumn tags permit attributes to be set for the next cell.
• the first cell in each row can have a tagTableColumn tag preceding it if necessary in order to change its attributes.
• the rowSpan and colSpan parameters are 0-based, which means that a value of 0 in these fields means 1 row and 1 column respectively.
• the width and height parameters can be 0 to make them automatically determined by the cell contents.
• Bit headerCell // 1 for header cell, // 0 for data cell
• the tagHyperlink tag is only used to define hyperlinks.
• the tagAnchor tag defined below, is used exclusively to define local anchors.
• the hasTitle bit can be set if a title is included. Normally, documents sent wirelessly will not include a title in order to conserve space.
• this hyperlink is to another location within the same document (i.e. a link to a tagAnchor), then internal will be set to 1 and the anchorlndex parameter indicates the index of a local tagAnchor to jump to.
• the first tagAnchor in the document is index 0, the next one is index 1, etc.
• the recordlndex parameter indicates which web resource to go to, 0 means the current web resource.
• a non-zero value represents the database record ID of the new web resource and is only used for wireless communications device 100 PQP databases that have multiple web resources stored in them - each in it's own record.
• Tag tag tagHyperlink
• Tag tag tagHyperlink
• Tag tag tagHyperlink
• the tagAnchor tag is only used to define local anchors.
• the tagHyperlink tag, defined above, is used exclusively to define hyperlinks.
• tagAnchors don't need an associated name since the tagHyperlink tag jumps to tagAnchors by index.
• the first tagAnchor in a document is index #0, the second is index #1, etc.
• documents designed to be installed onto the Handheld computer through HotSync or wireline means might include the anchor names so that other documents could include hyperlinks that jump to that location using a fragment identifier URL (something like http://www.mine.eom/#anchorName).
• Bit ismap // true if hyperlink
• Image imageData // image data [TBD...]
• Tag tag taglmage Text "This is an image of a PalmPilot"
• the method comprises translating the
• the HTML message into a compact markup language (CML).
• the HTML message comprises HTML constructs.
• CML representation of HTML constructs comprises a stream of data with embedded tags.
• the embedded tags comprise binary data corresponding to the HTML constructs.
• the stream of data comprises text and image data.
• the text data comprises multibit character representation for selected characters, eight bit representations for a first set of unselected characters, and sixteen bit representations for a second set of unselected characters.
• the second message typically contains information requested by the wireless client 405.
• the second message is often referred to herein as the response message, but could be any message that requires formatting of an HTML message in CML prior to communication to a requesting host.
• the data sent to the wireless client 405 from the proxy server 180 is in CML that is generated dynamically from the original HTML document.
• the wireless client 405 gets the HTML source directly from the web server.
• the head start and end tags enclose the document head and are optional.
• Every CML document is defined to start with a title string terminated by an endTag character.
• a place holder for future versions of HTML which may support style sheets.
• the tagStyle tag and associated endTag character are The tagStyle tag and associated endTag character.
• a place holder for future versions of HTML which may support client-side scripts.
• the ISINDEX element is a simple way to implement a single line text input field. The same behavior can be accomplished through use of a single field FORM element in the body.
• ISINDEX elements are translated into CML representations for a form in the body portion - there is no dedicated CML tag for ISINDEX.
• the BASE element gives the base URL for dereferencing relative URLs.
• CML documents do not contain hotlink URLs so no equivalent to this field is necessary.
• the wireless client 405 simply tells the proxy server 180 when the user clicks on a hotlink by passing the hotlink's index to the proxy server 180.
• the proxy server 180 looks up the appropriate URL using the original document.
• the META element can be used to include name/value pairs describing properties of a document such as author, expiration date, etc.
• the NAME attribute specifies the property name while the CONTENT attribute specifies the property value.
• META elements are represented by tagMeta CML tags.
• the LINK element provides a media independent method for defining relationships with other documents and resources. Very few browsers take advantage of it.
• the body start and end tags enclose the document body and may be omitted.
• the body section starts immediately after the endTag-character terminated title in a CML document and does not have an associated tag.
• the TEXT, BGCOLOR, LINK, VLINK, and BACKGROUND attributes are represented by the standalone CML tags tagTextColor, tagBGColor, tagLinkColor, tagLinkColor, and tagBGImage respectively.
• the HI through H6 tags are used for document headings. Start and end tags are required. HI elements are more important than H2 elements, and so on.
• Heading elements are represented by the corresponding tagHl..tagH6 CML tags.
• the BR element forces a line break.
• the CLEAR attribute can be used to move down past floating images on either margin.
• BR elements are represented in CML as 1 or more imbedded line- break characters in the text.
• the P tag signifies a paragraph break and is typically rendered as a line break followed by a blank line (i.e. another line break).
• the end tag is optional because it can be inferred by the parser.
• the P tag will be replaced with 1 or more imbedded linebreak characters in the text. If the align attribute is specified, then a tagParagraphAlign CML tag will also be placed at the beginning (and possibly end) of the paragraph.
• the DIV element can be used to stmcture an HTML document as a hierarchy of divisions.
• the CENTER element is equivalent to DIV with an ALIGN attribute of CENTER. This element differs from the P element in that it doesn't generate 2 line breaks (with the accompanying blank line).
• the HR element renders a horizontal line across the page and is used to indicate a change in topic.
• This element is represented by the tagHorizontalRuIe CML tag.
• the UL tag is used for unordered lists.
• the LI element is used for individual list items within the list. Examples:
• the UL tag will be replaced with the tagListUnordered CML tag.
• List items are separated from each other by endTag characters and the entire list is terminated by an endTag character. For example:
• Tag tag tagListUnordered
• Type enum Can be any one of 1, a, A, I, or I Start number Specifies the starting sequence number Compact void Render list in a more compact style
• the OL tag is used for ordered (numbered) lists.
• the LI element is used for individual list items.
• CML Representation The OL tag will be replaced with the tagListOrdered CML tag. List items are separated from each other by endTag characters and the entire list is terminated by an endTag character. For example:
• the MENU and DIR elements are essentially the same as UL elements.

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• 1999
  • 1999-05-26 CA CA2333033A patent/CA2333033C/en not_active Expired - Fee Related
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  • 1999-05-26 AU AU44078/99A patent/AU4407899A/en not_active Abandoned
  • 1999-05-26 DE DE69942202T patent/DE69942202D1/de not_active Expired - Lifetime
  • 1999-05-26 GB GB0030382A patent/GB2357222A/en not_active Withdrawn
  • 1999-05-26 EP EP99927094A patent/EP1092186B1/de not_active Revoked
  • 1999-05-26 WO PCT/US1999/011682 patent/WO1999062268A2/en active Search and Examination
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