Page 304 - Cloud computing: From paradigm to operation

1 Framework and requirements for cloud computing

9.6 Cloud services switchover and switchback

The cloud services switchover and switchback capability deals with the switchover of the CSC's end-user
access to cloud services from the primary CSP to a peer CSP to which the services may be provided in order
to cope with degradation in service performance or a serious problem. It also deals with the switchback to
the primary CSP when it is able to provide the services again. It should be noted that the reasons for switch-
over ranges from a load distribution between CSPs, in which the primary CSP role is maintained as it is, to a
serious problem, in which the primary CSP role is delegated to the peer CSP. The capability differences to
reflect those reasons need further study.
The cloud service switchover and switchback capability is recommended to:
– allow switching over CSC's end-user access to a peer CSP (acting as primary CSP) without manual
operation from the CSC, in order to allow the CSC's end user to use services in a similar manner to
the way they did before the access was switchover;
– allow switching back the CSC's end-user access to the primary CSP when this CSP has recovered from
the reasons that led to the switchover (e.g., a disaster or load distribution between peer CSPs is no
longer needed).

9.7 Resource release

The resource release capability deals with the release by a CSP of the peer CSPs' (reserved and/or used)
resources after determining that these resources are no longer needed, e.g., based on monitoring the results
such as disaster recovery has been completed or load has been reduced.

The resource release capability is recommended to:
– allow releasing by the CSP of resources reserved, activated and/or set up in the peer CSPs;
– allow updating the peer CSP's resource configuration information;
– allow erasing and/or transferring back cloud application data received during the resource
reservation.

9.8 CSC information exchange

The CSC information exchange capability deals with exchanging CSC profiles and associated information
between a primary CSP and the secondary CSPs. The information associated with a CSC is initially maintained
by the primary CSP. When the primary CSP requests that the secondary CSPs should provide additional
resources and run applications over the secondary CSP resources, the secondary CSPs may need to perform
customer management by inheriting the CSC profiles and associated information given by the primary CSP.
Activation of CSC information exchange needs prior agreement of the CSC.
The CSC information exchange capability is required to:

– be activated only with the prior agreement of the CSC;
– be able to manage CSC profiles and associated information.
The CSC information exchange capability is recommended to:
– be able to exchange CSC profiles and associated information among multiple CSPs according to a
pre-determined protocol and format, with the condition that the CSC is informed of and agrees to
the exchange.

9.9 Primary CSP role delegation
The primary CSP role delegation capability deals with transferring the primary CSP role to one of the
secondary CSPs, e.g., in the event of a serious problem caused by natural disasters or permanent service
termination occurring at the current primary CSP. In preparation for the serious problem or permanent
service termination at the primary CSP, all management information associated with the primary CSP is
shared with the secondary CSPs, while the absolute controllability of the information, i.e., permission to
update the information, is still held by the primary CSP. When the serious problem or service termination

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