In today’s world the emerging cloud computing offers a new computing model where resources such as computing power, storage, online applications and networking infrastructures can be shared as “services” over the Internet. However, the prevalent commercial CPs, operating in isolation (i.e. proprietary in nature), often face resource over-provisioning, degraded performance, and SLA violations (i.e. cloud service outages), thus incurring high operational costs and limiting the scope and scale of their services. Present trends in cloud service providers capabilities give rise to the interest in federating or collaborating clouds, hence allowing providers to revel on increased scale and reach than that is achievable individually.