&quot;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.&quot;<p>That&#x27;s not how BGP works. There&#x27;s no such thing as getting the best path from the first packet in terms of latency. There&#x27;s nothing in BGP that tell you about the path in terms of latency or performance. The only &quot;best&quot; that BGP gives you is AS path length between you and the destination. It tells you nothing about congestion&#x2F;packet loss upstream. The only way to get that is out of band probing, like taking latency measurements and pref&#x27;ing routes. There is no approach beyond &quot;after the fact&quot;<p>There is nothing in this article that talks about optimization of routes.