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Abstract
The convergence of recent technology advances opens the way to new ubiquitous environments,
where network-enabled devices collectively form invisible pervasive computing and
networking environments around the users. These users increasingly require extensive applications
and capabilities from these devices. Recent approaches propose that cooperating
service providers, at the edge of the network, offer these required capabilities (i.e services),
instead of having them directly provided by the devices. Thus, the network evolves from
a plain communication medium into an endless source of services. Such a service, namely
an overlay application, is composed of multiple distributed application elements, which cooperate
via a dynamic communication mesh, namely an overlay association. The Quality
of Service (QoS) perceived by the users of an overlay application greatly depends on the
QoS on the communication paths of the corresponding overlay association.
This thesis asserts and shows that it is possible to provide QoS to an overlay application by
using alternate Internet paths resulting from the compositions of independent consecutive
paths. Moreover, this thesis also demonstrates that it is possible to discover, select and
compose these independent paths in a distributed manner within an community comprising
a limited large number of autonomous cooperating peers, such as the fore-mentioned service
providers. Thus, the main contributions of this thesis are i) a comprehensive description
and QoS characteristic analysis of these composite alternate paths, and ii) an original
architecture, termed SPAD (Super-Peer based Alternate path Discovery), which allows the
discovery and selection of these alternate paths in a distributed manner. SPAD is a fully
distributed system with no single point of failure, which can be easily and incrementally
deployed on the current Internet. It empowers the end-users at the edge of the network,
allowing them to directly discover and utilize alternate paths.