2.3. Cloud platform comparison
There are many enterprises currently employ Cloud services in order to improve the scalability of their services
and to deal with bursts in resource demands. However, at present, service providers have inflexible pricing,
generally limited to flat rates or tariffs based on usage thresholds, and consumers are restricted to offerings from a
single provider at a time. Also, many providers have proprietary interfaces to their services thus restricting the
ability of consumers to swap one provider for another. Cloud computing uptake has only recently begun and many
systems are in the proof-of-concept stage. Regulatory pressures also mean that enterprises have to be careful about
where their data gets processed, and therefore, are not able to employ Cloud services from an open market. This
could be mitigated through SLAs that specify strict constraints on the location of the resources. However, another
open issue is how the participants in such a market can obtain restitution in case an SLA is violated (Buyya, Yeo,
Venugopal, Broberg, & Brandic, 2009).