Page 297 - Cloud computing: From paradigm to operation

Framework and requirements for cloud computing 1

– Connectivity between CSCs and CSP. By means of this connectivity, CSCs can use, operate, and
manage their cloud services provided by CSPs. CSCs do not know on which CSPs their services
actually run, but network connectivity facilitates access of CSCs to the appropriate CSP.
Figure 8-5 illustrates an example of configuration involving a Software as a Service (SaaS) CSP and multiple
Infrastructure as a Service (IaaS) CSPs forming an inter-cloud federation. The SaaS CSP uses virtual machines
(VMs) provided by IaaS CSPs which are members of the inter-cloud federation in order to provide SaaS
services (e.g., applications such as e-commerce) to its SaaS CSCs.

IaaS CSP
SaaS CSP (primary)
SaaS APP
CSC 1 IaaS CSP A
Network P Network Q VM (secondary)
SaaS APP
CSC 2
APP Network X VM
SaaS 4 VMs VM
CSC 3
IaaS CSP B
SaaS
CSC 4 Network Y APP
VM VM

IaaS CSP C
Network Z APP
VM
VM
End-to-end connectivity
Inter-cloud federation
APP: Application
VM: Virtual machine Y.3511(14)_F8-5

Figure 8-5 – View highlighting actual running VM and application locations

For the sake of simplicity, Figure 8-5 also shows network connectivity between different CSCs and CSPs
(illustrated with "Network" boxes). These "Network" boxes may be under the responsibility of third-party
providers different from the IaaS CSPs and SaaS CSPs, or may be provided by the IaaS and SaaS CSPs
themselves. These "Networks" are involved in the support of end-to-end network connectivity (between the
SaaS CSC and the "Application" running in the IaaS CSPs). Network connectivity supported by these
"Networks" may be provided as a cloud service of the NaaS service category. Network capabilities for the
support of NaaS service category are for further study.

By means of the connectivity provided by these networks, the SaaS CSCs can access the IaaS CSP on which
the VMs providing the service run. The SaaS CSCs do not know on which IaaS CSPs the VMs exist, but the
networks facilitate each access from SaaS CSCs to the appropriate IaaS CSP.

For the IaaS primary CSP, in order to achieve optimal resource use, it is desirable to handle information about
VM availability as well as their connectivity (including bandwidth, quality of service (QoS) and cost). The IaaS
CSP may choose to provide both computing and network resources jointly.
Multiple service offering scenarios including network contributions to the cloud services are described in
Appendix III.

8.2.4 Interactions in the case of inter-cloud federation
Figure 8-6 shows the interactions involving multiple CSPs in the case of the inter-cloud federation pattern. In
the inter-cloud federation, secondary CSPs provide their resources as one kind of service to the primary CSP.

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