Peering vs. transit: Performance comparison of peering and transit interconnections

The economic aspects of peering and transit interconnections between ISPs have been extensively studied in prior literature. Prior research primarily focuses on the economic issues associated with establishing peering and transit connectivity among ISPs to model interconnection strategies. Performance analysis, on the other hand, while understood intuitively, has not been empirically quantified and incorporated in such models. To fill this gap, we conduct a large scale measurement based performance comparison of peering and transit interconnection strategies. We use JavaScript to conduct application layer latency measurements between 510K clients in 900 access ISPs and multi-homed CDN servers located at 33 IXPs around the world. Overall, we find that peering paths outperformed transit paths for 91% Autonomous Systems (ASes) in our data. Peering paths have smaller propagation delays as compared to transit paths for more than 95% ASes. Peering paths outperform transit paths in terms of propagation delay due to shorter path lengths. Peering paths also have smaller queueing delays as compared to transit paths for more than 50% ASes.