Information Technology Reference
In-Depth Information
In a typical business scenario, customers specify their QoS requirements
and negotiate with the service provider for the terms of a service. During
the negotiation process, the service provider has the ability to provide
offers and counter-offers for individual requests according to the resource
availabilities and the economic considerations so as to maximize their
business benei ts [10].
The agreement-oriented service provisioning (which has been applied
to many aspects in our daily life) has a big market in the computer world
for providing network-based services with better quality and cooperation.
To realize that, efi cient SLA management services [11] are needed for
automating the process and facilitating the communications between the
service provider and its customer for SLA-relevant operations over dis-
tributed network environments. An SLA model is also required to describe
the SLA specii cations, such as QoS, cost, reliability, price, violation penalty,
and payment terms, in a structured way.
In this chapter, we present a model-based design of an SLA manager
which serves as a generic component to allow the client and service
provider to establish the SLAs before the service is delivered. Such an
SLA manager should be highly l exible and extensible to fuli ll complex
business requirements. Our SLA Manager is based on a lightweight core,
referred to as an “SLA-based service.” The service providers can easily
modify and tailor the SLA-based service by editing the service models to
meet their own needs. We adopt the common information model (CIM)
[12] for describing the meta-model using object-oriented constructs and
design. Most of the terminologies of our proposed SLA model follow the
WS-agreement [9] specii cations. We have tested our proposed SLA man-
ager on a distributed service-oriented platform called the shared services
platform [6]. The SLA manager can be easily incorporated to provide cus-
tomized SLA management services for various applications within this
platform. The SLA-based service allows the service provider to manage
the copies of SLAs, retrieve the SLA templates, and facilitate the client and
the service provider to propose and counter-propose SLAs. In the rest of
this chapter, we will describe the model of our proposed SLA manager,
the implementation of the SLA model and the SLA-based service, and the
working scenarios that demonstrate service interactions. We use the i re
dynamic simulator (FDS) as an example of high-performance application
services over the shared services platform.
This chapter is organized as follows. The next section presents the
related work. This is followed by an introduction to the framework of the
model-based SLA manager and describes the creation of the model-based
SLA management service over the SSP and the interactions with other
components. We then present the CIM model of the SLA and show how it
works in SLA negotiations. Finally, we describe the implementation of a
prototype and its performance for providing a high-performance applica-
tion service, FDS, over the SSP.
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