Page 318 - Cloud computing: From paradigm to operation

1 Framework and requirements for cloud computing

In the service expansion shown in Figure III.1-c, two new resources that are different from the primary CSP's
resource are added by secondary CSPs A and B. These might be software packages or platform-type
applications. With the support of the secondary CSPs, the primary CSP can offer a wide-variety service, which
now consists of various service components.

From the viewpoint of inter-cloud patterns, which are described in clauses 7 and 8, inter-cloud federation is
suitable for volume-based service expansion. The description of the inter-cloud federation in clause 8.2
focuses on resource reservation, use and release. Inter-cloud intermediary is suitable for variety-based
service expansion. The description of the inter-cloud intermediary in clause 8.3 underlines the significance of
the catalogue of service offerings.

III.2 Service operation enhancement
Inter-cloud interaction enables not only service expansion as described in clause III.1, which matters more at
the beginning of a service offering, but can also enhance the ways that services are offered. This relates more
to the entire process of offering a service.

Figure III.2 shows two such enhancements.

CSC CSC

Primary CSP Primary CSP Secondary CSP

a) Basic model – c) Reliable service offering with secondary CSP –
Two units are offered to a user. Despite problems with primary CSP, two units
are offered without interrupting the user.

CSC CSC

Primary CSP Secondary CSP Primary CSP Secondary CSP

b) Volume expansion – d) Elastic service –
Three units are offered beyond primary capacity One to three units are offered
according to user's demand.
Y.3511(14)_FIII.2

Figure III.2 – Operational enhancement in inter-cloud computing

In Figure III.2, volume expansions are assumed. For the sake of comparison, Figures III.2-a and III.2-b depict
item expansion as already discussed in clause III.1, whereas cases c) and d) depict operation enhancement.
The basic scenario is shown in Figure III.2-a again, which offers two resource units (e.g., two VMs) to a user.
A simple service item expansion is shown in Figure III.2-b.
With the help of secondary CSPs, the primary CSP can keep offering the service even if something unexpected
happens to the primary CSP, which is shown in Figure III.2-c. Due to the availability of cloud technology across
multiple CSPs, the secondary CSP can compensate for the unavailable resources by offering alternative
resources on behalf of the primary CSP. The primary CSP can offer the same service continuously with
minimal or no interruption to the user.

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