Evaluating Transport Protocols for Real-Time Event Stream Processing Middleware and Applications

Real-time event stream processing (RT-ESP) applications must synchronize continuous data streams despite fluctuations in resource availability. Satisfying these needs of RT-ESP applications requires predictable QoS from the underlying publish/subscribe (pub/sub) middleware. If a transport protocol is not capable of meeting the QoS requirements within a dynamic environment, the middleware must be flexible enough to tune the existing transport protocol or switch to a transport protocol better suited to the changing operating conditions. Realizing such adaptive RT-ESP pub/sub middleware requires a thorough understanding of how different transport protocols behave under different operating conditions. This paper makes three contributions to work on achieving that understanding. First, we define ReLate2, which is an evaluation metric that combines packet latency and reliability to evaluate transport protocol performance. Second, we use the ReLate2 metric to quantify the performance of various transport protocols integrated with the OMG’s Data Distribution Service (DDS) QoS-enabled pub/sub middleware standard using our FLEXible Middleware And Transports (FLEXMAT) prototype for experiments that capture performance data. Third, we use ReLate2 to pinpoint configurations involving sending rate, network loss, and number of receivers that show the pros and cons of the protocols.