An Investigation on Flexible Communications in Publish/Subscribe Services

Abstract

Abstract. Novel embedded and ubiquitous infrastructures are being realized as collaborative federations of heterogeneous systems over widearea networks by means of publish/subscribe services. Current publish/subscribe middleware do not jointly support two key requirements of these infrastructures: timeliness, i.e., delivering data to the right destination at the right time, and flexibility, i.e., enabling heterogeneous interacting applications to properly retrieve and comprehend exchanged data. In fact, some middleware solutions pay more attention to timeliness by using serialization formats that minimize delivery time, but also reduce flexibility by constraining applications to adhere to predefined data structures. Other solutions adopt XML to improve flexibility, whose redundant syntax strongly affects the delivery latency.We have investigated the consequences of the adoption of several lightweight formats, which are alternative to XML, in terms of flexibility and timeliness. Our experiments show that the performance overhead imposed by the use of flexible formats is not negligible, and even the introduction of data compression is not able to manage such issue.

Architectural Evolution of Monitor and Control Systems - Issues and Challenges

“…The widely used solution to offer flexibility is to adopt XML as serialization format. However, XML redundant syntax strongly affects the delivery latency, as shown in [37]. On the other hand, the publish/subscribe middleware that are largely adopted in critical scenarios, such as the ones compliant with the OMG standard called Data Distribution Service (DDS) [38], pay more attention to timeliness by using serialization formats that minimize the bytes exchanged through the network, with the advantage of reducing delivery time but with the drawback of compromising flexibility by constraining applications to adhere to predefined data structures.…”