Cloud computing is a computing paradigm offering on-demand access to computing
resources such as storage, security, software, monitoring, infrastructure, etc., via
Internet. All these services are offered on a pay-as-you-go model and the operational
costs become more important than the fixed costs. The upfront cost is minimal or zero
in most of the cases. Cloud computing has basically three service models as: IaaS
(Infrastructure as a Service), in which infrastructure such as hardware and storage,
are provided to users as a service; PaaS (Platform as a Service), in which it provides
platforms like operating systems or software development environment to programmers
and users for building and running your programs; and Software as a Service (SaaS),
in which it provides software applications and programs like documents editing services,
messaging services, etc., to users. These applications and programs are run locally
through the user’s Internet browsers on a pay-as-you-go basis or on monthly or yearly
subscription basis. In all these transaction and relationships, the service level
agreements play an important role to control the usage, quality levels and billing of
the computing resources (Beardmore, 2009). Companies migrating to the cloud
computing look towards the SLAs to give them some level of comfort about availability,
performance, quality, maintenance, monitoring, security and so on.
SLA is an agreement signed and agreed between the user and the cloud service
provider. Terms and conditions mentioned on SLA must satisfy the users before they
start using or taking a service. Different cloud providers offer different types of SLAs
based on their terms and conditions. SLA provides information to the user about the
service levels offered in terms of quality of services, response time, availability, and so
on. It records a common understanding about services, priorities, responsibilities,
guarantees and warrantees. In cloud computing, SLAs are necessary to control the
use of computing resources (Takabi et al., 2010). An SLA can provide secure
collaboration and assure that services are provided according to preestablished rules
(Almutairi et al., 2012). The SLA is generally presented by the vendor, but there is no
reason that an organization has to agree to terms without discussion or additional
interaction with an organization. The bottom line is that consumers are responsible to
make sure that the SLA is fair and that it meets their needs (Cohen, 2012). SLA
becomes the basis of formal understanding and communication between the service
provider and the consumer. However, it basically defines the relationships between
two parties. An SLA plays a vital role in building trust in cloud computing environment
between the service consumers and service providers. Hence, it becomes necessary to
investigate the relationship between the SLAs and trust building.
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