Probabilistic FIFO Ordering in Publish/Subscribe Networks
In a best-effort publish/subscribe network, publications may be delivered out of order (e.g., violating FIFO order). The authors contend that the primary cause of such ordering violations is the parallel matching and forwarding process employed by brokers to achieve high throughput. In this paper, they present an end-to-end method to improve event ordering. The method involves the receiver and minimally the sender, but otherwise uses the broker network as a black box. The idea is to analyze the dynamics of the network, and in particular to measure the delivery delay and its variation, which is directly related to out-of-order delivery.