Home > Articles

This chapter is from the book

Pervasive Client Technologies: WAP and MMS

WAP browser and MMS messaging client are two technology pillars supported by all Nokia Developer Platforms. We cover the basics of those two technologies in this section.

Introducing WAP

A WAP browser works pretty much the same way as the HTML Web browser on a desktop PC. The user interacts with the remote application server by following dynamic links and submitting forms. The handset renders the content provided by the server. All the application logic is processed on the server side.

Although mobile and desktop browser applications share the same application model, the actual network architecture and markup languages are different. We check out those differences in the next several sections.

Network Architecture

While an HTML Web browser can make direct HTTP connections to the server, the WAP browser must go through a gateway server to connect to the general TCP/IP Internet. The WAP infrastructure is illustrated in Figure 2-11. The gateway converts data packets from the wireless network to TCP/IP format and then forwards them onto the wired Internet, and vice versa.

02fig11.gif

Figure 2-11 The WAP network infrastructure.

From the Web application developer's point of view, however, the gateway is almost completely transparent. All the developer needs to do is set up a normal HTTP server to serve the markup pages and other media objects. HTTP headers, including cookies and authentication credentials, pass through the gateway transparently. The gateway also handles encrypted HTTPS connections automatically.

WML

For developers, the biggest difference between an HTML Web application and a WAP wireless application is the different markup languages. Most mobile browsers support the Wireless Markup Language (WML), and all Nokia Series 40 and 60 devices support the WML specification. A core element in WML is <card>. Unlike HTML, where one page corresponds to one screen, one WML download page can contain a deck of cards denoted by the <card> tag. Each card corresponds to one screen and mobile device, and the user can navigate between cards using internal reference links. The cards help to break long content into several screens without requiring multiple round trips to fetch them one by one from the server. For example, the WML snippet below shows a deck of WML cards in one page, and Figure 2-12 shows how it looks on a device. The <do> tag maps a text label to a soft key. When the user presses on the soft key, the browser navigates to the page or card URL specified in the enclosed <go> tag.

<?xml version='1.0'?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.2//EN"
          "http://www.wapforum.org/DTD/wml_1.2.xml">
<wml>
  <card id="Name" title="Enter Name">
    <do type="accept" label="SayHello">
      <go href="#Hello"/>
    </do>
    <p>Please enter your name:
      <input type="text" name="name"/>
    </p>
  </card>

  <card id="Hello" title="Say Hello">
    <p>Hello, $(name)</p>
  </card>
</wml>
02fig12.gif

Figure 2-12 A deck of WML cards displayed on a cell phone screen.

XHTML MP

The XHTML markup language is developed by the W3C to replace HTML. It is HTML-defined as an XML document with cleaner and stricter syntax. Series 60 devices and some Series 40 devices feature dual-mode WAP browsers that support both WML and XHTML. The browser conforms to the XHTML Mobile Profile (MP) specification, which contains a subset of most widely used XHTML tags. A key benefit of the dual-mode browser is that it allows users to access the vast amount of Web content out there on the wired Internet. The XHTML browser also supports WAP cascading style sheets (CSS) for styling.

Details about the WAP infrastructure, applications, markup languages, and Nokia device browsers can be found in Chapter 15, "Browser Applications."

Introducing MMS

An MMS message is analogous to an email message on the wired Internet. It contains a text body and any number of multimedia file attachments. The MMS client in Nokia Series 40 and 60 devices supports all popular attachment types, including JPEG, GIF, PNG, and MIDI. Some devices support advanced formats such as AMR TrueTone audio and 3GPP mobile video clips. You can send an MMS message to any MMS-enabled phone or ordinary email address. The message is delivered as follows:

  1. The sender composes a message and sends it to the carrier's Multimedia Messaging Service Center (MMSC).
  2. The MMSC forwards the message to the recipient carrier's MMSC or email server via the wired Internet.
  3. The message is delivered to the recipient's phone or email inbox.

As we can see, the MMSC is central to the MMS architecture. We can write applications that connect to the MMSC directly over the wired Internet and send automated messages to a large number of users (see Figure 2-13).

02fig13.gif

Figure 2-13 The MMS network architecture.

An interactive MMS application functions like an automated email information service. It works as follows:

  1. The user requests an application action by sending messages to the server.
  2. The server returns the results via messages delivered to the phone.
  3. The user then makes a further request by replying to that message.

This process goes on until the user stops replying to the message, thereby ending the session (see Figure 2-14).

02fig14.gif

Figure 2-14 The MMS application interaction diagram.

SMIL

In addition to the text and multimedia components, the MMS message can also include a presentation component written in a special XML format called Synchronized Multimedia Integration Language (SMIL), which is also a W3C standard. A SMIL document contains time sequence instructions on how to display the attached multimedia components. The following SMIL example code instructs the MMS client to display image demo.gif and text demo.txt simultaneously on different parts of the screen for four seconds. At the same time, the client should play the demo.midi audio file.

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE smil PUBLIC "-//W3C//DTD SMIL 2.0//EN"
      "http://www.w3.org/2001/SMIL20/SMIL20.dtd">
<smil xmlns="http://www.w3.org/2001/SMIL20/Language">
  <head>
    <layout>
      <root-layout width="320" height="240"
                    title="Demo"/>
        <region id="Image" width="150" height="60"
                                    left="0" top="0"/>
        <region id="Text" width="150" height="35"
                                  left="0" top="70"/>
    </layout>
 </head>
 <body>
    <par dur="4s">
      <img src="demo.gif" region="Image"/>
      <text src="demo.txt" region="Text"/>
      <audio src="demo.midi"/>
    </par>
  </body>
</smil>

Not all devices support the SMIL component in MMS messages. Some earlier Series 40 devices ignore the SMIL attachment altogether but still allow the user to access other attachments in the MMS message. More details of the MMS infrastructure, applications, and SMIL are available in Chapter 14, "Multimedia Messaging Service."

The Thin-Client Application Paradigm

The WAP and MMS applications both run on servers. The handsets merely render the content and capture user interaction. This is commonly known as the thin-client application paradigm. It is a proven success in the Internet-based applications. Key advantages of this thin-client application model include the following:

  • The clients are pervasively available. WAP browsers are almost universally supported by all device manufacturers and network carriers. The SMS and MMS messaging services are also widely available throughout the world. Several factors contribute to the pervasiveness of those technologies:
    • Since the device only handles presentation, it does not require much processing power. WAP browsers and messaging clients can be implemented on small, low-end devices with high sales volumes and long battery lives.
    • Since WAP has been around for a long time, most wireless data networks are well equipped to handle WAP traffic reliably. That makes thin-client applications available all over the world.
    • WML, XHTML, SMIL, and MIME attachments are standard technologies with a huge installed base worldwide. Most compatibility problems have been worked out over the years.
  • Thin-client applications and developers are readily available.
    • The Web application and email application models are well known to today's Internet developers. They can easily migrate their skills to the new wireless arena.
    • A large number of Web applications are available today. It is relatively easy to make changes to their presentation layer so that they generate WML pages instead of HTML pages.
  • Thin-client applications are installed and deployed on the server end. There are no complex and costly provisioning process, license management, security update, and so forth.

However, a crucial disadvantage of the thin-client paradigm is that it requires the mobile device to be always connected. Today's wireless data networks are slow, unreliable, and expensive. They cover only limited areas. Those limitations have severely hindered the adoption of thin-client applications. To get around the network problem, we have to rely on the other two pillars in the Nokia Developer Platforms: J2ME and Symbian C++.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020