Page 293 - Cloud computing: From paradigm to operation

Framework and requirements for cloud computing 1

7.2 Inter-cloud federation

Inter-cloud federation involves using the cloud services within a group of peer CSPs who mutually combine
their service capabilities in order to provide the set of cloud services required by cloud service customers
(CSCs).

The multiple CSPs, which form the inter-cloud federation, establish and share the common agreement which
may range from service-related policies, service level agreements (SLAs) and procedures which are relevant
to the service offering and resource handling.
Based on the agreement, a CSP in the inter-cloud federation can offer its cloud services with the help of other
CSPs.

A common API for cloud interworking is defined in the inter-cloud federation. As shown in Figure 7-3, each
CSP interworks with the other CSPs in the inter-cloud federation through this common API.

It should be noted that the inter-cloud federation pattern does not necessarily require the fully meshed
configuration of CSPs interacting with each other as shown in Figure 7-3.

Inter-cloud federation

CSP B
CSC 1 Service X

CSP A CSP C
Service Y Common
CSC 2 API

Service Z
CSC 3 CSP E CSP D

Y.3511(14)_F7-3

Figure 7-3 – Inter-cloud federation

7.3 Inter-cloud intermediary

In the inter-cloud intermediary pattern, the CSP interworks with one or more peer CSPs and provides
intermediation, aggregation and arbitrage of services provided by these CSPs.
Service intermediation consists in conditioning or enhancing the cloud service of a peer CSP. Service
aggregation relates to the composition of a set of services provided by the peer CSPs. Service arbitrage is
about selecting one service offering from a group of services offered by the peer CSPs.

Interworking between a CSP providing service intermediation, aggregation and arbitrage and the peer CSPs
can rely on either the inter-cloud peering pattern or the inter-cloud federation pattern. Figure 7-4 illustrates
the inter-cloud intermediary pattern where CSP A provides intermediation, aggregation and arbitrage of
cloud services provided by CSPs B, C, D and E.

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