| Summary: | Interactive multimedia sessions combine requirements of traditional
telephony services and Internet applications. This requires call setup,
call signaling, negotiation, routing, security, and network resources.
Seeking to facilitate the use of quality of service (QoS) mechanisms to
users of such applications,
this thesis presented new signaling
architectures that addressed the interaction of the Session Initiation Protocol (SIP)
as the session
control signaling protocol and current resource management frameworks.
The Differentiated Services (DiffServ) architecture is used as the primary example.
The new architectures
addressed the roles of SIP agents and proxy servers in subjects
such as resource negotiation, call authorization, and end-to-end QoS
in heterogeneous networks.
First, an architecture based on the use of QoS-enhanced SIP proxies
and a SIP-based interface between the application and network layers
was developed, implemented in a testbed, and performance enhancements
demonstrated. Further studying of the Internet Engineering Task Force (IETF)
proposal for the integration of SIP and resource management led to the
development of a new signaling scheme, Resource management
Overlapped with Answering Delay (ROAD). It explores the SIP user agent
interaction with the network in a way that takes advantage of parallel
user answering delays and reservation delays. An experimental evaluation of the
ROAD scheme showed its call setup delay savings and reduced signaling load.
Then, on the interaction of SIP and call admission control, an inter-domain
call authorization model that implements the concepts of proxies as gate
controllers (QoS-enhanced SIP proxies-GC), and that provides call authorization
status and adds more granularity to the authorization process is proposed.
This model showed to be scalable in terms of the need to add more resources
to compensate for the increasing service load on the servers. Finally, an example
framework that applies the new signaling architectures to achieve end-to-end
QoS in heterogeneous networks is presented.
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