Jahresbericht 2006 - Biba - Universität Bremen

MSA
The IP Multimedia Subsystem (IMS)
is a Next Generation Networking (NGN)
architecture for telecommunications services
standardised by the 3rd Generation
Partnership Project (3GPP) and fixed services
standardised by the ETSI Telecoms
& Internet converged Services & Protocols
for Advanced Networks (TISPAN) group.
IMS was defined using Internet
protocols standardised by the Internet
Engineering Task Force (IETF). Specifically,
IMS builds on the IETF Session Initiation
Protocol (SIP) with a few extensions standardised
by 3GPP and running over the
Internet Protocol (IP).
IMS aims to provide access to services
to both stationary and mobile users,
regardless of the type of network they
currently roam. Both packet-switched
and circuit-switched telecommunications
systems are supported and any combination
of IMS and Internet users can setup
a session between them.
Furthermore, IMS was designed not
only as a ubiquitous service delivery
platform, but also as an integration
platform for both current and future
services, both telecommunications and
Internet services. IMS merges the Internet
with the mobility paradigm for application
developers by enabling the use of
cellular technologies to provide ubiquitous
access and Internet technologies to
provide appealing services.
The IMS architecture for communication
services consists of a number of
components; (a) basic IMS communication
services like push-to-talk over cellular,
IMS Messaging, charging and multimedia
telephony supported by clients in the
terminal as well as SIP application servers
in the network (b) enabling services like
presence and SIP Push. All of these are
basic elements in a solution which provides
end-user services.
Provision of complex multimedia
services composed of individual service
components requires aggregation logic
to support the creation and execution
of such services, as well as to guarantee
prevention of unwanted and unforeseen
side effects (often referred to as feature
interaction) between them. Given the
complexity of such aggregations and
both the amount of work as well as the
possibility of unforeseen side effects
it is required to foresee a method for
automating this process as strongly as
possible.
The main objectives of Project „Multi-
Service Architecture for the Next Generation
of telecommunication services“ (MSA)
is to investigate existing service composition
approaches towards resolving
these issues and implementing a service
composition prototype for SIP services
based on the J2EE Architecture.
Eugen Freiter
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