Page 321 - Cloud computing: From paradigm to operation

Framework and requirements for cloud computing 1

The SaaS CSCs expect an application service to be provided by the SaaS CSP. In reality, the SaaS CSP relies on
IaaS CSP resources and runs its application over the IaaS-CSP's resources. From the IaaS CSP's perspective,
the IaaS CSP should, at least:
1) provide VMs, which are now distributed over multiple secondary IaaS CSPs,
2) keep running the application over the distributed VMs, and
3) allow continuous access to the distributed applications from the user (i.e., SaaS CSC users).

In response to the expectations of 1), 2), and 3) above, specific requirements are derived.
The requirements on general resource handling in clauses 9.1, 9.2, 9.3, 9.4, and 9.7 relate to 1).
The requirements on resource set-up and activation in clause 9.5 relate to 2).

The requirements on switchover and switchback of the cloud service user access in clause 9.6 relate to 3).
In a simple implementation, these different networks are designed and operated independently. Such a
network configuration is straightforward and easy to operate. However, it may cause inefficient operation,
where the user traffic path traverses through an unnecessary route with longer delay. In more sophisticated
implementations, the locations of these users, providers and VMs are taken into account and more efficient
operation will be achieved.
The capabilities of the networks shown in Figure III.5 may be further offered as NaaS. The detailed
requirements and functions for NaaS are under study.

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