Page 387 - Cloud computing: From paradigm to operation
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Framework and requirements for cloud computing                              1


            Below arethe key characteristics of cloud computing described in [ITU-T Y.3500]:
            −       Broad  network  access:  a feature where  the  physical  and  virtual  resources  are  available over a
                    network and accessed through standard mechanisms that promote use by heterogeneous client
                    platforms. The focus of this key characteristic is that cloud computing offers an increased level of
                    convenience in that users can access physical and virtual resources from wherever they need to
                    work, as long as it is network accessible, using a wide variety of clients including devices such as
                    mobile phones, tablets, laptops and workstations.
            −       Measured service: a feature where the metered delivery of cloud services is such that usage can be
                    monitored, controlled, reported and billed. This is an important feature needed to optimize and
                    validate the delivered cloud service. The focus of this key characteristic is that the customer may
                    only pay for the resources that they use. From the customers' perspective, cloud computing offers
                    the users value by enabling a switch from a low efficiency and asset utilization business model to a
                    high efficiency one.
            −       Multi-tenancy:  a  feature  where  physical  or  virtual  resources  are  allocated  in  such  a  way  that
                    multiple tenants and their computations and data are isolated from and inaccessible to one another.
                    Typically, and within the context of multi-tenancy, the group of cloud service users that form a
                    tenant will all belong to the same cloud service customer organization. There might be cases where
                    the group of cloud service users involves users from multiple different cloud service customers,
                    particularly in the case of public cloud and community cloud deployments. However, a given cloud
                    service  customer  organization  might  have  many  different  tenancies  with  a  single  cloud  service
                    provider representing different groups within the organization.
            −       On-demand  self-service:  a  feature  where  a  cloud  service  customer  can  provision  computing
                    capabilities, as needed, automatically or with minimal interaction with the cloud service provider.
                    The focus of this key characteristic is that cloud computing offers users a relative reduction in the
                    costs, time and effort needed to take an action, since it grants the user the ability to do what they
                    need, when they need it, without requiring additional human user interactions or overheads.
            −       Rapid elasticity and scalability: a feature where physical or virtual resources can be rapidly and
                    elastically adjusted, in some cases automatically, to quickly increase or decrease resources. For the
                    cloud service customer, the physical or virtual resources available for provisioning often appear to
                    be  unlimited  and  can  be  purchased  in  any  quantity  at  any  time  automatically,  subject  to  the
                    constraints  of  service  agreements.  Therefore,  the  focus  of  this  key  characteristic  is  that  cloud
                    computing means that customers no longer need to worry about limited resources and might not
                    need to worry about capacity planning.
            −       Resource pooling: a feature where a cloud service provider's physical or virtual resources can be
                    aggregated  in  order  to  serve  one  or  more  cloud  service  customers.  The  focus  of  this  key
                    characteristic is that cloud service providers can support multi-tenancy while at the same time using
                    abstraction  to  mask  the  complexity  of  the  process  from  the  customer.  From  the  customer's
                    perspective,  all  they  know  is  that  the  service  works,  while  they  generally  have  no  control  or
                    knowledge over how the resources are being provided or where the resources are located. This
                    offloads  some  of  the  customer's  original  workload,  such  as  maintenance  requirements,  to  the
                    provider. Even with this level of abstraction, it should be pointed out that users might still be able
                    to specify locations at a higher level of abstraction (e.g., country, state, or data centre).
            The general requirements for cloud computing described in [ITU-T Y.3501] are as follows:
            −       Service  life-cycle  management:  It  is  required  that  the  cloud  service  provider  (CSP)  supports
                    automated service provisioning, modification and termination during the service life-cycle.
            −       Regulatory: It is required that all applicable laws and regulations be respected, including those
                    related to the protection of personally identifiable information (PII).
            −       Security: It is required that the cloud computing systems provided by a CSP be appropriately secured
                    to protect the interests of all involved parties (e.g., persons and organizations).




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