[nine_k]

Not only latency but possibly also the cost / availability of massive egress. This is why e.g. YouTube has local caches around the world. Other heavily-hit caches with heavy content may make sense, too; I can't easily imagine a case beside serving video, though.

[cortesoft]

It is also about pure network capacity.... if all of the traffic on the internet has to traverse the entire path to a central data center, there wouldn't be enough backbone capacity

[jon-wood]

Steam and other game distribution systems also have an extensive network of edge caches around the world, and Linux distros have had local mirrors since forever.

It’s also pretty common for people running large LAN parties to run a local Steam cache so that when everyone in the building decides to download a game on the list of tournaments it’s coming over the local network rather than downloading hundreds of copies from the Internet.

[xmprt]

That's an interesting point. However, I wonder if there are extra costs to serve a request from Australia to the US (there are definitely extra costs but I wonder if either the user or server pay them). If these costs are exposed to either of the ends, then it might be cost effective to create something that serve requests from local caches.

[toast0]

I don't know about now, but many years ago, it was common for some Australians to have different prices or caps to AU vs non-AU destinations, and for some European customers to pay more for trans-atlantic traffic. I've never seen destination specific charging in the US.

My guess is the cost differences are still there, but the increases in capicity and decreases in all costs combined with the difficulty of users to control traffic at that level mean that you would really only see this if you're buying a lot of transit. If you're just a residential customer, it might be more likely to impact you as your ISP may have more congestion on oceanic routes rather than an explicit charge.

I do occassionally see hosting operators that will optionally charge more for access to some routes that are better but too costly to include in a bundled rate.

[tomnipotent]

> if either the user or server pay them

Most of the big operators have peering agreements in place, but that doesn't mean every participant has infinite bandwidth. Google Global Cache and Netflix Open Appliance go a long way to reducing costs by avoiding interconnect where possible.