Tatsuya Yamazaki
Study on Communication Coordination
Abstract:Motivated by coordinating multimedia communication service from the end-user's
viewpoint in heterogeneous communication environments and with various
individual requirements, this report proposes a networking architecture and a QoS
(Quality-of-Service) management framework. Upon the whole, one main characteristic
of the proposed methods is to control QoS at the application level in
connection with the upper and lower levels, assuming best-effort type infrastructures.
Chapter 1 describes the backgrounds, motivation, objectives and abstract of
this report. In Chapter 2, the notion of QoS considered through this report is defined,
and based on it, a layered QoS model is shown. In order to link different
QoS levels, QoS mapping plays an important role by translating QoS parameters
between different QoS levels. A QoS mapping method using Spline functions
is proposed. Relevance of QoS between application and user levels is also discussed.
Chapter 3 proposes a networking architecture for heterogeneous communication
environments, where a proxy server located between sender and receiver
sites transforms media QoS according to available computational and network resources
and user's requirements. A prototype of the proxy server is developed
for video image transmission applications. In Chapter 4, an adaptive QoS management framework for distributed media is proposed based on the multi-agent
system. One feature of this framework is its 2-tier QoS management. Namely the
long-term QoS adaptation is executed in one tier, while the short-term QoS adjustment
is executed in the other tier. A one-way video system is developed based
on the proposed framework. Chapter 5 presents applications of the proxy server
architecture and the multi-agent-based framework to realistic environments. An
error resiliency scheme using both channel and source coding techniques is proposed
in consideration of QoS management. Then, a QoS management architecture
combining the proxy server architecture and the multi-agent-based framework
is discussed. Also, an application of the proxy server to home networks is
described. Chapter 6 presents an idea of multimedia communication coordination
that meets a QoS policy agreement based on a layered QoS model. The multimedia
communication coordination consists of system-oriented and user-oriented coordinations. As a typical application, a chat system with video transmission is
introduced. Chapter 7 concludes this report and describes the future problems.