You may be able to view what routes I announce but you still have no idea what my route policy is like. I might prefer one upstream over another due to pricing, latency, capacity or any other unknown reason. And that is never published. If you can not know my egress, you will not know my ingress either as that would be someone else egress and you can not know their egress.... You could use RIPE Atlas or the NLNOG RING to do traceroutes. That would give you an idea of how traffic actually flows. Knowing the routes tells you nothing about how much traffic will be exchanged. How do you know which ASN has a deal with a big CDN or which ASNs are content heavy vs eyeball heavy? Only the source or destination ASN can know for sure how much traffic is exchanged. Regards, Baldur