On Fri, 14 Aug 2015, Martin T wrote:
there are various tools out there which show the prefix distribution among the peers/uplinks for given ASN. For example https://radar.qrator.net/as3333/graph#96311 or http://bgp.he.net/AS3333#_asinfo. As far as I know, those tools build the graphs mainly based on data from route servers. Am I correct that at best this data could give very rough estimation on ingress traffic for ASN as those graphs indicate announced prefixes? I mean for example if ASN 1 announces 1.1.0.0/16, 2.2.0.0/16 and 3.3.0.0/16 to ASN 2, but only 1.1.0.0/16 to ASN 3, then one could assume that more ingress data to ASN 1 goes over ASN 2. What about egress traffic? In general, are there ways to roughly estimate network traffic distribution for given ASN among its peers/uplinks? I would say it is not possible.
You can certainly make inferences about the traffic between ASN 1 and ASN 2, 3, etc... however without being the operator of one of those ASNs, those inferences are just that - inferences. Even if you operate a network that peers with both ASN 1 and ASN 3, the traffic you see transiting your network to get to/from them might only be a fraction of the total traffic between those ASNs, given the possibility of there being other paths between then that don't cross your network. What are you trying to figure out? If you want to see how much traffic you move between your AS and another AS, Netflow, IPFIX, and other tools can help you figure that out. If you're looking for the same kind of data for a source, destination (or both) that you don't control, all you can realistically do is guess. jms