LOcAl DEcisions on Replicated States (LOADER) in programmable data planes: programming abstraction and experimental evaluation

Abstract: Programmable data planes recently emerged as a prominent innovation in Software Defined Networking (SDN), by permitting support of stateful flow processing functions over hardware network switches specifically designed for network processing. Unlike early SDN solutions such as OpenFlow, modern stateful data planes permit to keep (and dynamically update) local per-flow states inside network switches, thus dramatically improving reactiveness of network applications to state changes. Still, also in stateful data planes, the control and update of non-local states is assumed to be completely delegated to a centralized controller and thus accessed only at the price of extra delay. Our LOADER proposal aims at contrasting the apparent dichotomy between local states and global states. We do so by introducing a new possibility: permit to take localized (in-switch) decisions not only on local states but also on replicated global states, thus providing support for network-wide applications without incurring the drawbacks of classical approaches. To this purpose, i) we provide high-level programming abstractions devised to define the states and the update logic of a generic network-wide application, and ii) we detail the underlying low level state management and replication mechanisms. We then show LOADER's independence of the stateful data plane technology employed, by implementing it over two distinct stateful data planes (P4 switches and OPP - Open Packet Processor - switches), and by experimentally validating both implementations in an emulated testbed using a simple distributed Deny-of-Service (DoS) detection application.