[ctime]

The internet is a decentralized collection of autonomous systems (AS) and the primary benefit of this setup isn’t exactly realized afaict, which is multiple paths via different carriers. Your BGP AS is advertised via N paths, so your IP networks are thus reachable via multiple paths. Systems will take the shortest/best path adding to redundancy and throughput. Compared that to “business” service without routing options, when your “dedicated” connection drops, your IP addresses are no longer reachable from the greater internet.

[bogomipz]

>"The internet is a decentralized collection of autonomous systems (AS) and the primary benefit of this setup isn’t exactly realized afaict, which is multiple paths via different carriers."

The primary benefit if fully-realized and is not about "is multiple paths via different carriers."

An AS is an administrative entity. Route prefixes belong to an AS. All routes with an AS have a common routing policy that is managed by a single entity. I can look up a prefix to find it's AS and then I can look up that AS's routing policies. Here is an example for Tier 1 ISP Spring:

https://www.sprint.net/policies/bgp

I could have single ISP that I buy transit from and I might have multiple links with them. If I want to understand how to take advantage of that for example with traffic engineering then I would look the policies for ISPs AS. I would then use those BGP community attributes on my BGP links to them in order to accomplish my own routing goals.