Availability of service; what happens when the service provider
cannot deliver?

• Diversity of  services, data organization, user interfaces available
at different service providers limit user mobility; once a customer is
hooked to one provider it is hard to move to another.
Standardization efforts at NIST!

• Data confidentiality and auditability, a serious problem.

• Data transfer bottleneck; many applications are data-intensive .

Performance unpredictability, one of the consequences of resource
sharing.
– How to use resource virtualization and performance isolation for QoS
guarantees?
– How to support elasticity, the ability to scale up and down quickly?

• Resource management;  are self-organization and self-management
the solution?

• Security and confidentiality;  major concern.

• Addressing these  challenges provides good research
opportunities!!