As promised in the previous post, A look into Dublin Traceroute results, this time we will see how a graphical representation can highlight things that we wouldn’t normally see immediately. The diagram in detail Let’s look again at the graphical traceroute shown in Observing ECMP with Dublin Traceroute: The diagram is quite self-explanatory, but let’s see it in detail anyway. At the top, the destination (126.96.36.199), at the bottom the source, my laptop (192.
In the previous post, Observing ECMP with Dublin Traceroute, I briefly talked about ECMP and showed how to visualize all (well, hopefully) the paths between two nodes A and B. In particular I had run dublin-traceroute from a 3G connection in Ireland towards Google’s public DNS, 188.8.131.52. This is a very interesting IP address, as it is a DNS, it is deployed via anycast, and is widely distributed around the world, so I will use it often thorughout this blog.
Being a new blog, let’s start with an introductory post :) A small introduction to ECMP Dublin Traceroute has been created with multi-path networks in mind. It is very common in large networks to use ECMP to spread packets across multiple paths in order to improve reliability, increase bandwidth and more. While very useful, ECMP introduced some challenges when running traceroute on this kind of networks. For example, it’s not possible to anticipate which path each packet will take, and since there are multiple possible paths, a regular traceroute may show impossible connections.
Welcome to Dublin Traceroute’s new blog! Here I will post about how to use Dublin Traceroute, discussion about new features and interesting things I find out in the process. Feel free to use comments to start a conversation!