Path Selection Based on Single Direction Delay Difference

Because of the asymmetry of paths, the single direction delay becomes more important in network measurement and applications design. We proposed a method to select path for packet sending based on Single Direction Delay Difference (S3D). It can get the shortest single direction delay on the send and receive direction path. This method doesn´t need clock synchronization or the exact value of single direction delay. We make use of the modified HEARTBEAT mechanism in SCTP to probe delay which won´t increase the additional overhead. We also implement our method in Linux. Under the test topology, the performance of our method is compared with SCTP by changing the parameters of single direction delay, packet loss, receive buffer and bandwidth. The results show that the S3D method can bring better throughput when the send and receive direction delay are quite different.