Wireless Application Environment or WAE:
The Wireless Application Environment, or WAE,
provides an architecture for communication between wireless devices and Web
servers. To understand WAE, you should first be familiar with the World Wide
Web (WWW) model, which is a simpler architecture based on similar
In the WWW model, a browser requests a URL from a Web server via HTTP. That Web server responds with an HTML page, which is also sent via HTTP. Because all browsers speak HTTP and both client and server speak the same protocol, they can communicate directly.
Hardware and Software Requirement:
At minimum developing WAP applications requires a web server and a WAP simulator. Using simulator software while developing a WAP application is convenient as all the required software can be installed on the development PC.
Although, software simulators are good in their own right, no WAP application should go into production without testing it with actual hardware. The following list gives a quick overview of the necessary hardware and software to test and develop WAP applications:
A web server with connection to the Internet
A WML to develop WAP application
A WAP simulator to test WAP application
A WAP gateway
A WAP phone for final testing.
Microsoft IIS or Apache on Windows or Linux can be used as the web server and Nokia WAP Toolkit version 2.0 as the WAP simulator.
Environment of WAE:
WTLS(Wireless Transport Layer Security):
Wireless Transport Layer Security is a protocol based on the TLS protocol. It is used with the WAP transport protocols and has been optimised for use over narrow-band communication channels. The WTLs layer is above the transport protocol layer. The required security layer of the protocol determines whether it is used or not. It provides a secure transport service interface that preserves the transport service interface below; additionally it provides an interface for managing secure connections. WTLS aims to provide privacy, data integrity and authentication between two communication applications. Among its features are datagram support, optimised handshaking and dynamic key refreshing. It is optimised for low-bandwidth bearer networks with relatively long latency.
The WTLS Record Protocol is a layered protocol. The Record Protocol takes messages to be transmitted, optionally compresses the data, applies a MAC, encrypts, and transmits the result. Received data is decrypted, verified, and decompressed, then delivered to higher-level clients. Four record protocol clients are described in the WTLS standard; the change cipher spec protocol, the handshake protocol, the alert protocol and the application data protocol. If a WTLS implementation receives a record type it does not understand, it ignores it. Several records can be concatenated into one transport SDU. For example, several handshake messages can be transmitted in one transport SDU. This is particularly useful with packet-oriented transports such as GSM short messages.
WTP( Wireless Transaction Protocol):
The Wireless Transaction Protocol provides the services necessary for interactive browsing applications. During a browsing session the client requests information from a server and the server responds with the information. This is referred to as a transaction. WTP runs on a datagram service and possible a security service.
Advantages of WTP include:
Improved reliability over datagram services
Imported efficiency over connection oriented services
As a message oriented protocol, it is designed for services oriented towards transactions.
3 kinds of transaction services.
Class 0 Unreliable invoke messages with no result messages
Class 1: Reliable invoke messages with no result messages
Class 2: Reliable invoke messages with exactly one reliable result message.
Reliability achieved by using unique transaction identifiers, acknowledgements, duplicate removal; and retransmissions.
No explicit set up or tear down phases.
Optional user-to-user reliability.
Optionally the last acknowledgement of the transaction may contain out-of-band information.
Concatenation may be used to convey multiple PDUs in one service data unit of the datagram transport.
The basic unit of interchange is an entire message, not a stream of bytes.
Mechanisms are provided to minimize the number of transactions replayed as a result of duplicate packets.
Abort of outstanding transactions.
For reliable invoke messages, both success and failure reported.
Asynchronous transactions allowed.
WSP(Wireless Session Protocol):
The Session layer protocol family in the WAP architecture is called the Wireless Session Protocol, WSP. WSP provides the upper-level application layer of WAP with a consistent interface for two session services. The first is a connection-mode service that operates above a transaction layer protocol WTP, and the second is a connectionless service that operates above a secure or non-secure datagram transport service.
The Wireless Session Protocols currently offer services most suited for browsing applications. WSP provides HTTP 1.1 functionality (it is a binary form of HTTP) and incorporates new features such as long-lived sessions, a common facility for data push, capability negotiation and session suspend/resume. The protocols in the WSP family are optimized for low-bandwidth bearer networks with relatively long latency. Requests and responses can include both headers and data. WSP provides push and pull data transfer WSP functions on the transaction and datagram services.
Messages can be in connection mode or connectionless. Connection mode messages are carried over WTP. In this case the protocol consists of WTP protocol messages with WSP PDUs as their data. Connectionless messages consist only of the WSP PDUs.