Flexible Content-based Publish/Subscribe over Programmable Data Planes.

Publish/subscribe systems have to react fast on changes in their environment while handling many events with low end-to-end latency and high throughput. Moving the broker functionality of publish/subscribe systems to the underlying network layer reduces the path length of events and, in addition, forwarding benefits from powerful and programmable hardware. So far attempts of underlay publish/subscribe depend on a specific API of the network devices, e. g., the OpenFlow protocol, which have restrictions in dealing with dynamic devices and corresponding changes in the introduced attribute names for matching and filtering events.In this work, we focus on the next generation of network devices, which are envisioned to provide reconfigurable hardware components, specified by the open P4 description language. We introduce two new approaches that enable a flexible and generic attribute/value encoding, understandable by P4-capable packet processors, to benefit from the performance properties of hardware. Furthermore, the proposed approaches reduce the effort in encoding and decoding event messages.