P4xos: Consensus as a Network Service

In this paper, we explore how a programmable forwarding plane offered by a new breed of network switches might naturally accelerate consensus protocols, specifically focusing on Paxos. The performance of consensus protocols has long been a concern. By implementing Paxos in the forwarding plane, we are able to significantly increase throughput and reduce latency. Our P4-based implementation running on an ASIC in isolation can process over 2.5 billion consensus messages per second, a four orders of magnitude improvement in throughput over a widely-used software implementation. This effectively removes consensus as a bottleneck for distributed applications in data centers. Beyond sheer performance, our approach offers several other important benefits: it readily lends itself to formal verification; it does not rely on any additional network hardware; and as a full Paxos implementation, it makes only very weak assumptions about the network.