Inter Cloud Interoperability Use Cases and Gaps in Corresponding Standards

Growing use of cloud computing is leading to Anything-as-a-Service (XaaS). The economics of cloud computing, supported by advancements in associated technologies have made it a more viable IT solution for various businesses. To meet this increasing demand, Cloud Service Providers (CSPs) now need to build elasticity; to meet customer requirements which are beyond their own resources and may have to be met by securely collaborating with other CSPs. Leveraging cloud concepts and technologies to establish a cloud of clouds, can take us to the next level of cloud computing, with enormous potential. However, due to vast range of cloud services, use cases for inter cloud interoperability can also be substantial. This paper ascertains all possible use cases of inter cloud collaboration, and their corresponding interoperability standards and protocols. Some research has already been done to achieve interoperability between clouds by setting architectural principles and standards based on use cases. However different authors have formulated inter cloud use cases in different ways. This paper highlights use cases for which appropriate inter cloud interoperability standards or protocols are yet to be established. Large number of proprietary standards has made development of common standards a challenge. Measures for security and privacy of user data need to be designed to give users control over their data. This includes trust mechanism as user data or services shift from one cloud to another. Other areas identified as lacking to have common inter cloud standards/ protocols include exchange of pay load, VM mobility, IP mobility and resource management. Challenges to achieve inter cloud interoperability have been identified and gaps in existing standards have been underlined to suggest future research areas. The concept in nutshell is to accrue cloud benefits between various heterogeneous clouds to achieve a possible cloud of clouds.