WAP stands for Wireless Application Protocol. This is a well-known and commonly used standardized protocol which defines how wireless communication can take place between mobile devices and a wireless network. This could include devices such as radio transceivers, cell phones, world wide web, newsgroup, instant messaging and any device that can be used for Internet access. Devices which are based on WAP can interoperate as technology advancement happens over time.
WAP was originally brought in by four companies collectively. This includes Motorola, Nokia, Ericsson and Unwired Planet (currently known as Phone.com). WML is known as Wireless Markup Language and is used to create pages that can be transmitted using WAP. At the highest level, the WAP layers are:
- WAE – Wireless Application Environment
- WSP – Wireless Session Protocol
- WTP – Wireless Transport Protocol
- WTLS – Wireless Transport Layer Security
- WDP – Wireless Datagram Protocol
This was initially developed in 1999 and formed a major technical standard for accessing information over mobile wireless networks. This consists of a WAP browser which is a browser used to access WAP connections.
How does WAP work?
An actual implementation of WAP works as mentioned below:
- The user would turn on the device such as mobile phone and open a mini WAP browser. This would use the URL you wish to browse with WML (Wireless Markup Language) content assigned to it.
- The device would send this request to a WAP gateway using a binary encoded WAP protocol.
- Next, the gateway is responsible for translating the WAP request to a normal HTTP request and send this on to the Internet.
- An appropriate web server would pick up this request.
- The web server does not specifically distinguish this request from another HTTP request. The web server will add HTTP header to the response which is encoded as WML and returns it to the gateway.
- The WAP gateway converts the WML content to binary form and sends it back to the device.
- The mini WAP browser processes the WML content and displays it over the device.
This would display the wireless internet version of the web page you have requested. In order to create such content, a website would require a low graphics or special text-only version of the website. Internally this is encoded from HTTP format to WML to ensure appropriate rendering over the WAP-enabled devices.
Between the gateway and the client, there are a series of tasks which are implemented and are part of the WAP protocol stack. The WAP protocol stack looks as shown below:
- WSP (Wireless Session Protocol) – WSP determines whether the session between any device will be connectionless or connection-oriented. This determines the communication between the device and the network. In case of the connectionless session, Wireless Datagram Protocol (WDP) is used for information to be broadcasted over the network to the device. In case of connection-oriented, WSP uses Wireless Transaction Protocol (WTP) to send packets.
- WTP (Wireless Transaction Protocol) – This is responsible to classify each transaction and allow data to flow in a logical manner. This could be classified as Unreliable one-way, Reliable one-way or reliable two-way. The WSP and WTP layers correspond to HTTP.
- WTLS (Wireless Transport Layer Security) – This has a function similar to the TLS (Transport Layer Security) in TCP/IP. This checks the overall security of WAP transactions and is responsible for encryption, data integrity and server authentication.
- WDP (Wireless Datagram Protocol) - This works together with the network carrier layer. This makes the transfer of data using WAP simpler.
- Network Carriers – These are also called as bearers. This can be any of the technologies that wireless networks use. The bearer is used for transmitting information provided at the WDP level.
Post this, the WAP client would receive this information which would be passed to the mini browser. The browser exists within the wireless device and acts as an interface between the user and the wireless internet. The mini browser has a very minimum level of browsing and navigation features.
Shortcomings of WAP:
- Low speed
- Low security enabled features
- Small and not very friendly user interface
- Third-party dependency
- Designing forms are hard
- The business model can get expensive