Tracking Network Flows with P4

Tracking flows within a single device, as well as tracking the full path a flow takes in a network are core components in securing networks. Malicious traffic can be easily identified and its source blocked. Traditional methods have per- formance and precision shortcomings, while new programmable devices open up new possibilities. In this paper we present methods based on the P4 programming language that allow to track flows in a device, as well methods toward full path tracking. A core component of this work are Bloom filters, which we have implemented fully in P4. To validate our approach and implementation we have carried a study in a specific use case, namely the detection of SYN attacks.