Page 35 - Cloud computing: From paradigm to operation

Framework and requirements for cloud computing 1

The following DaaS general requirements are described in [ITU-T Y.3503] as follows:
– Support for high-definition (HD) and three-dimensional (3D) applications: DaaS can optionally
support execution of HD applications on virtual desktops for CSCs;
– Extensible storage: It is recommended that a CSP support the storage extension requested by a CSC;
– Response time: It is recommended that DaaS provide CSCs with acceptable QoE;
– High availability: It is recommended that high availability in terms of delivery and operation of DaaS
be assured by a CSP;
– Resiliency to disaster: In the case of a disaster, DaaS is recommended to provide and maintain an
acceptable level of service;
– Service continuity: It is recommended that in the case of temporarily unavailable resource access,
a CSP provides the capability to preserve the state of the user session;
– System scalability: It is recommended that DaaS supports elastic scalability of:
• Storage for DaaS user account information, virtual desktop environment settings and active and
inactive virtual desktop environments;
• Processing and network capacity for the number of concurrent DaaS user connections and total
DaaS users;
• Underlying DaaS resources.
– DaaS developer environments: It is recommended to provide a developer environment for the
service and contents regarding DaaS;
– Diversity of DaaS clients: It is recommended that the CSP support a wide selection of DaaS clients.
NOTE – Functional requirements for DaaS are provided in clause 8 of [ITU-T Y.3503].

10 General requirements for PaaS
The general requirements for platform as a service (PaaS) derived from the use cases in clause I.5 are as
follows:
– Application hosting: It is required that the PaaS CSP provides an application hosting environment,
where the application can be rapidly deployed, reliably executed, flexibly expanded and isolated
from other applications;
– Services delivery platform: It is recommended that the PaaS CSP provides the capabilities of service
presence, orchestration, billing, mash-up and tools for associated development and testing by CSCs
through a unified application programming interface (API);

– Integrated development environment: The PaaS CSP can optionally provide comprehensive
capabilities to CSCs for software development such as coding, debugging, compiling and
distribution;
– Development tools: PaaS CSP can optionally provide development tools as a service to CSCs, who
can use it on-demand.

11 General requirements for CaaS
The general requirements for communication as a service (CaaS) derived from the use cases in clause I.6 are
as follows:
– Communication capabilities openness: It is recommended that the CSP provides APIs for accessing
communication capabilities of CSNs to enhance their own services by using communication
enablers;
– Communication software development support: It is recommended that the CSP provides support
for communication software development, which is a group of communication building blocks, to
CSNs in order to develop communication applications;

NOTE – Examples of communication building blocks are protocol stacks, codecs, authentication, etc.

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