The Virtue of Gentleness: Improving Connection Response Times with SYN Priority Active Queue Management

We have analyzed network traces of TCP connections and observed that there are many more losses during the handshake than for the remainder of the data exchange. Although recently developed AQM schemes can efficiently reduce latency related to bufferbloat, only more complex solutions relying on Fair Queueing (FQ) can improve the long delays resulting from the loss of a packet during the establishment of a TCP connection. In this paper, we propose SPA (SYN Priority Active queue management), a new low-complexity queue management scheme that combines the benefits and simplicity of the most recent AQM schemes while achieving performance comparable to more complex combinations of Fair Queueing and AQM. Our evaluation shows that the SPA performance is close to FQ CoDel for only a fraction of the complexity and resource usage.