Wireless Application Protocol Overview & Layers
WAP stands for Wireless Application Protocol.
WAP represents a group of protocols rather than a single protocol.
WAP aims at integrating a simple lightweight browser also known as a micro-browser into handheld devices, thus requiring minimal amounts of resources such as memory and CPU.
The primary objectives of the WAP protocols are the following.
- Independence from the wireless network standards
- Interoperability among service providers
- Overcoming the shortfalls of the wireless medium
- Overcoming the drawbacks of handheld devices
- Increasing efficiency and reliability
- Providing security, scalability, and extensibility
The WAP Model
WAP adopts a client-server approach.
It specifies a proxy server that acts as an interface between the wireless domain and core wired network.
This proxy server, also known as a WAP gateway, is responsible for a wide variety of functions such as protocol translation and optimizing data transfer over the wireless medium.
Wireless network parts consist of −
- Content provider (Application or origin server)
- Mobile device (WAP client)
- WAP gateway
- WAP proxy
WAP Client
The three sections to be mentioned regarding WAP client are WAE user agent, WTA user agent and WAP stack.
- WAE user agent − Wireless application environment user agent is the browser that renders the content for display.
- WTA user agent − Wireless telephony application agent receives compiled WTA files from WTA server and executes them.
- WAP stack − WAP stack allows the phone to connect to the WAP gateway using the WAP Protocols.
Application Server
The elements in the network where the information (web, WAP) applications reside are WAP proxy, WAP gateway or WAP server −
- Proxy − This is an intermediary element acting both as a client and as a server in the network. It is located between client and server.
The client sends requests to it and it retrieves and caches the information needed by contacting the origin Server.
- Gateway − This is an intermediary element usually used to connect two different types of networks.
Application Layer
The application layer provides an application environment intended for the development and execution of portable application and services WAE consists of two different user agents located on client side.
The WAE user agent consists of browser and the text message editor along with the WTA user agent.
Session Layer
The session layer supplies methods for the organized exchange of content between Client/Service applications.
WAP contains the following components −
- Connection Oriented Session Services − These operate over WTP.
- Connectionless Session Services − These operate directly over WDP.
- Session services − These functionalities help to set up a connection between a client and server using primitive messages.
Transaction Layer
Provides different methods for performing transactions to varying degree of reliability. It runs on top of UDP (User Datagram Protocol) and is a part of TCP/IP and offers transaction support.
Security Layer
This layer contains Wireless Transport Layer Security (WTLS). It provides services that ensure privacy, server authentication, client authentication and data integrity. It offers data integrity, privacy and authentication.
Transport Layer
This is the bottom layer, connected with the bearer service offered by the operator. Bearer services are the communication between the mobile phone and the base stations. They include SMS, GSM, GPRS, CDMA, FDMA, TDMA, etc
The physical layer prepares the data to be sent from the mobile device over the air services and sends the data using bearer service implemented in the network that the device is operating in.
What is the Use of Wireless Application Protocol?
The following advantages for wireless network operators, content producers, and end users were put out by WAP when it was first introduced in 1999:
Operators of wireless networks and mobile phones:
WAP was created with the intention of enhancing already-existing wireless data services, such as voicemail, and facilitating the creation of new mobile applications. Without making any further infrastructure adjustments or phone modifications, these applications might be created.
Content Provider:
For third-party application developers, WAP opened up a market for extra applications and mobile phone features. It was suggested that developers use the WML programming language to write applications for mobile devices.
End users:
Access to online services like banking, entertainment, messaging, and other information on mobile devices should be simple and safe for users of mobile phones. WAP could also permit access.
Advantages of Wireless Application Protocol
The benefits of Wireless Application Protocol, or WAP, are listed below:
- WAP is a rapidly evolving technology.
- Wireless Application Protocol is an open source that is totally free of cost.
- WAP can be used over multiple platforms.
- Neither it nor network standards are affected.
- Higher controlling possibilities are offered.
- It follows a model that is similar to the Internet.
- You can send and receive real-time data with WAP.
- WAP is supported by the majority of current mobile phones and devices.
Disadvantages of Wireless Application Protocol
The following is a list of various Wireless Application Protocol, or WAP, drawbacks:
- WAP connection speed is slow and number of connections are less.
- At some places it is very difficult to access the Internet, and also at some places it is totally impossible.
- Less secure.
- WAP provides a small User interface (UI).