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architectures are responsible for providing mechanisms for specification and enforcement
of QoS that make use of the resource reservation protocols provided by the underlying
system. QoS architectures deal with issues such as the translation of QoS parameters
comprehensible at the application-level into the parameters understood by the
underlying reservation protocols that control access to the resources provided by the
system. Without the services provided by a QoS architecture, these issues would have
to be dealt with by the application which would make the programmers as well as users
task complex and difficult
Research into QoS architectures ([CCH98], [Siq99] and asdiscussed in later sections) show
folowing features :
_ Most architectures need a higher level abstraction at the
application level. And this
what they aim at.
_ Most architectures assume a particular underlying network and then build a
middleware that provides QoS to the applications abov like Aquila (European IST funded
project) assumes DiffServ network, QoS-A assumes ATMnetwork etc.
_ Usually, the mapping is done in a static manner tosome network services
created/assumed at the underlyingnetwork.
_ Resource allocation modules co-ordinate at the middle-ware in a distributed
enviroment using architectures likeCORBA etc.
Also, to most appropriately assign QoS resources network
wide, the technology
needs to have a mechanism which calculates and provides the required resources
based on the network state and application requests.
Multi Protocol Label Switching (MPLS) is choice of future technology as it has
capability to perform traffic engineering. Details of MPLS are explained in earlier section.
Thus, the objective of the thesis is to come up with an
efficient mapping
mechanism and QoS architecture for MPLS networks. The core issue in the architecture
will be the mapping between SLA at the application level to the QoS parameters at
the network level. We should be able to create
a standard language to specify application QoS requirements
and then be able to map them to the network parameters.
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