Page 319 - Cloud computing: From paradigm to operation

Framework and requirements for cloud computing 1

Another scenario, shown in Figure III.2-d is to offer an elastic service, in which the service capacity is adjusted
in accordance with the user's demand. In this scenario, the secondary CSP should start and stop its resource
offering according to the primary CSP's control. Interaction with the user involves changing the resource
offering.

III.2.1 CSC-initiated operation and CSP-initiated operation

Looking at the scenarios in Figure III.2 from the viewpoint of who initiates operations, the reliable service in
Figure III.2-c and the elastic service in Figure III.2-d are different.

With the reliable service, the service continuity should be achieved without disturbing the user. The problem
should be solved on the CSP side, without necessarily revealing the problem to the user. This may impose a
specific requirement. In order not to disturb the user, the primary and secondary CSPs should move the user
application, if necessary, and continue the service by themselves. This may include installation and activation
of the user application.

The requirement for resource set-up and activation, which is described in clause 9.5, corresponds to this
case.

With the elastic service, the CSC may change the use of the CSP's resources explicitly or the primary CSP may
change the resource offerings by somehow sensing the CSC's demand.

III.3 Consideration on network connectivity
The description here is meant to supplement clauses 8.2.3 and 8.3.3 on network connectivity.

Networks should, at least, support connectivity between the CSC and the CSP, between the CSPs, and within
the CSPs. Based on the primary-secondary model of inter-cloud computing over multiple CSPs, these network
parts correspond to:
1) a network between the CSC and the primary CSP;
2) networks between the primary and the secondary CSPs;
3) a network in the primary CSP, and;

4) networks in the secondary CSPs.
From the CSP's perspective, networks 1) and 2) are external, whereas networks 3) and 4) are internal.

Figure III.3 explicitly shows the external networks of 1) as "Network Q" and 2) as "Network X", "Network Y",
and "Network Z".

CSC
Primary CSP
CSC's application

Network Q
Secondary CSP A

Network X
Secondary CSP B

Network Y
Secondary CSP C

Network Z
Y.3511(14)_FIII.3

Figure III.3 – Networking in inter-cloud

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