WAP is an open international standard for applications that use
wireless communication. Its principal application is to enable access to the Internet
from a mobile phone or PDA.A WAP
browser provides all of the basic services of
a computer based web browser but simplified to operate within the restrictions
of a mobile phone. The Japanese i-mode system is another major competing
wireless data protocol.WAP sites are websites written in, or dynamically
converted to, WML (Wireless Markup Language) and accessed via the WAP browser.
Before the introduction of WAP, service providers had extremely limited
opportunities to offer interactive data services. Interactive data applications
are required to support now commonplace activities such as:
email by mobile phonetracking of stock market
pricessports resultsnews headlinesmusic downloads
The bottom-most protocol in
the suite is the WAP Datagram Protocol (WDP), which is an adaptation layer
that makes every data
network look a bit like UDP to the upper layers by
providing unreliable transport of data with two 16-bit port numbers
(origin and destination). WDP is considered by all the upper layers as one
and the same protocol, which has several "technical
realizations" on top of other "data bearers" such as SMS, USSD,
etc. On native
ip bearers such as GPRS, UMTS packet-radio service, or PPP
on top of a circuit-switched data connection, WDP is in fact exactly UDP.
WTLS provides a public-key
cryptography-based security mechanism similar to TLS. Its use is optional.
WTP provides transaction
support (reliable request/response) that is adapted to the wireless world.
WTP supports more effectively than TCP the problem of packet loss, which
is common in 2G wireless technologies in most radio conditions, but is
misinterpreted by TCP as network congestion.
Finally,
WSP is best thought
of on first approach as a compressed version of HTTP.
This protocol suite allows a terminal to emit requests that have an HTTP or HTTPS
equivalent to a WAP gateway; the
gateway translates requests into plain HTTP.
More abstracts about the WAP-Wireless Application Protocol