Reliable Data Delivery for Publish/Subscribe Networks

Network architectures built completely on publish and subscribe primitives instead of send and receive, have recently attracted many researchers. Pub/sub paradigm changes the networking completely: end-to-end principle breaks, communication channels become unidirectional, and multicast becomes a norm. Although pub/sub has attracted many, the research has been focusing on the network layer – functionalities that lie on the higher layers have not been studied so thoroughly. This paper focuses on how reliability, which is normally addressed above networking layer, can be achieved in pub/sub networks. Reliability and guaranteed message delivery have traditionally been solved at the endpoints of the communication but the approach does not work anymore in pub/sub paradigm. The focus of this paper is on understanding the concept of reliability in publish/subscribe networks, how reliability has been solved in other (e.g. overlay) pub/sub architectures, and what are the fundamental requirements for reliable data transfer. In addition, recently proposed Cache-and-Forward architecture is used as an example when considering ways to achieve reliability in pub/sub networks.