Offloading Media Traffic to Programmable Data Plane Switches

According to estimations, approximately 80% of Internet traffic represents media traffic. Much of it is generated by end users communicating with each other (e.g., voice, video sessions). A key element that permits the communication of users that may be behind Network Address Translation (NAT) is the relay server. This paper presents a scheme for offloading media traffic from relay servers to programmable switches. The proposed scheme relies on the capability of a P4 switch with a customized parser to de-encapsulate and process packets carrying media traffic. The switch then applies multiple switch actions over the packets. As these actions are simple and collectively emulate a relay server, the scheme is capable of moving relay functionality to the data plane operating at terabits per second. Performance evaluations show that the proposed scheme not only produces optimal results regarding Quality of Service (QoS) parameters (no packet loss, minimum delay, negligible delay variation, high Mean Opinion Score) but also scales much better than current solutions. Evaluations conducted with up to 35Gbps of media traffic or its equivalent of 400,000 simultaneous G.711 media sessions (limited only by the traffic generator rather than by the switch) show an ideal operation of the switch-based solution (using$\sim \text{l}$% of the switching capacity). In contrast, a relay server with a modern CPU model used for evaluations can process up to 900 simultaneous G.711 media sessions per core.