TCP/IP Tutorial and Technical Overview - IBM Redbooks

Here, we give a brief description of the protocol stack:
Bearer networks Different bearer networks are allowed. As the transport
layer acts as an interface between the bearer service and
the upper layers of the WAP stack, the transport layer
specifications defines the supported bearers and the
functions implemented to access each bearer.
Transport services This service is in charge of transportation of unstructured
data across the underlying bearer networks, creating an
consistent abstract implementation across all of the
supported bearers. The transport services include
datagram and connection services among others.
Transfer services This service provides the implementation for the
structured data transfer of information between network
elements. Most popular services included are hypermedia
transfer (such as HTTP, Wireless Session Protocol, and
Wireless Transaction Protocol), streaming data (such as
audio and video), and message transfer (such as
Multimedia Message Services Encapsulation).
Session services This service establishes a shared state between network
elements. For example, services include capability
negotiation, push over the air, sync service, and cookies.
Application framework
This provides the general purpose application
environment based on a combination of World Wide Web
(WWW), Internet, and mobile technologies. The primary
objective of the application framework is to establish an
interoperable environment that will allow service providers
to build applications and services that will be supported by
a wide variety of different platforms in an efficient manner.
The application framework includes, among others, push,
multimedia messaging, and content formats.
Security services This is a fundamental part of the WAP architecture and it
is present in many of its layers. The services commonly
offered at this layer are authentication, privacy, integrity,
and non-repudiation.
Service discovery This is a fundamental part of the WAP architecture and
this can also be found at many layers. Some examples of
this are the external functionality interface (EFI),
provisioning, navigation discovery, and service lookup.
662 TCP/IP Tutorial and Technical Overview