Paper review: End to End Routing Behavior in the Internet

Reviewer: Kevin Hofstra

1. How effective is the internet in routing packets from 2 individual nodes across the infrastructure of the internet. What accounts for it reliability, speed, and performance?
2. A new evaluation of the performance of internet packet routing. A study of how quickly and reliably packets are delivered by investigating possible shortcomings of internet routing. It still applies today, especially when many of the services need to be reliable or even time sensitive.
3. The data was gathered using exponential sampling of traceroute data between multiple host sites over a varied amount of time. Routing loops account for most of the undeliverable packets where the propagation of downed links across the internet account for most of the delayed packets. Different pathologies are being taken more often as the internet grows and hop count increases, with asymmetric paths doubling between 94 and 95.
4. Critique the main contribution
• Significance- 2 The article is very effective in showing raw experimental data of times and routes across the internet, but traceroute is not an effective tool for seeing how the actual routing is being done in the internet. An end to end tool leaves much to question about why the data has come out like it has, and this requires a tool which has intelligence within the network.
• Convincing- 3 The data is gathered very well, but much of it is inconclusive because the end to end traceroutes don’t tell us much of what is going on internally.
5. From this article we learn many significant numbers about the reliability and growth of the internet and what this will do to effective routing. We know that the number of hops are increasing and the path differentiation increasing, while the reliability is decreasing. This leads me to believe we must make changes to our routing algorithms to more effectively prevent routing loops, and changes to the topologies must be propagated faster. But I think the most important question is whether the increase in asymmetry is a good thing for redundancy and load balancing or whether low path differentiation and constant paths will lead to more reliable links.