Impact of Overlay Routing on End-to-End Delay

The prosperity of various real-time applications triggers significant challenges for the Internet to meet the critical end-to-end delay requirements. This paper investigates the feasibility and practical issues of using overlay routing to improve end-to-end delay performance, with the analysis of round trip time data collected over three months by the all pairs pings project between each pair of hundreds of nodes on the Planet- Lab. The results show: 1) overlay routing has the potential to reduce the round trip time by 40 milliseconds and increase network connectivity by 7% on average; 2) even simple static overlay paths can reduce end-to-end delay, while the dynamic algorithm does better; 3) Over 80% of the shortest overlay paths have no more than 4 hops, and a simple algorithm leveraging only one relay node can efficiently take the advantages of overlay routing.