A Path-Diversity Protocol for the Invocation of Distributed Transactions over the Web

The notion of path-diversity has been widely used in the context of content delivery networks (CDNs) to improve system responsiveness by leveraging inherent features of multi-hop networks to reduce the likelihood to incur link congestions or failures. In this work we address the issue of how to exploit path-diversity in the context of application delivery networks (ADNs), namely the evolution of CDNs where the edge servers additionally host transactional logic for the access and manipulation of data on back-end data centers. As we will discuss, path-diversity based solutions are not trivial for Web-based transactional applications, especially in the case of transactions spanning multiple, autonomous data centers. In such a context we need in fact to deal with a set of issues not present in classical content delivery applications, such as distributed deadlocks potentially occurring for the processing of instances of a transactional request sent to multiple edge servers along different network paths. In this paper we propose a simple and lightweight path-diversity based protocol for the invocation of distributed transactions over the Web, which addresses all those issues in a scalable manner by requiring no form of coordination among the edge servers over the ADN