> Probing just 30% of the top prefixes is likely not enough for their use case. Probing is also an after the fact approach. Fastly needs a solution which will g

> Probing just 30% of the top prefixes is likely not enough for their use case. Probing is also an after the fact approach. Fastly needs a solution which will give best possible path from first packet. < Considering that Fastly deploys PoPs and not colos or datacenters, I think that the top 30% of their transit routes would be the lionshare of non-peer activity. Fastly's PoPs are generally at (or have reach to) the largest Internet exchanges for peering purposes. Peering routes are generally the best, cheapest, most concise routes you can get. You don't need a big, expensive router when you're in an exchange's peering mesh. Considering that you're only handling local traffic (by design of having multiple PoPs), peering plus two default transits will probably optimize for the traffic that matters most. Also as mentioned, you can't really determine "best possible path" without probing. You can see what BGP tells you, but that's not always the best possible path. People that run networks know this. That's why things like FCP/IRP/RouteScience exist (for better or worse). > Different game indeed. Netflix just cares about throughput, Fastly also needs low latency, hence the need for more optimizing. < Sure, but you won't get that optimization from BGP. In a Fastly PoP, you're mainly dealing with in-country or in-region eyeball networks. If you buy transit from 2-3 major networks, BGP probably won't help you with those eyeballs. The path length will probably be the same (the eyeballs either peer or buy transit from large tier 1s). You generally can't trust MED to do anything useful with it, so that's out. Those are the only 2 things BGP can use to impact route selection. If path length and MED are the same, it's a coin flip as to which path to take (not really as the first installed route is the winner). If you just took default routes and peered locally, you'd be much better off in a PoP scenario than trying to re-invent route reflectors and taking full BGP feeds.