3 ms·
How is this possible from a single location? The speed of light in a vacuum is ~200 miles per millisecond.
by fipple 9y ago
How is this possible from a single location? The speed of light in a vacuum is ~200 miles per millisecond.
- aftbit 9y agoDespite using a single IP, this is not served from a single location. Check out Anycast, wikipedia: https://en.wikipedia.org/wiki/Anycast https://en.wikipedia.org/wiki/Anycast
- tialaramex 9y agoYup, anycast, this is also why: The "backup" IPv4 address is 1.0.0.1 rather than, say, 1.1.1.2, and why they needed APNIC's help to make this work In theory you can tell other network providers "Hi, we want you to route this single special address 1.1.1.1 to us" and that would work. But in practice most of them have a rule which says "The smallest routes we care about are a /24" and 1.1.1.1 on its own is a /32. So what gets done about that is you need to route the entire /24 to make this work, and although you can put other services in that /24 if you _really_ want, they will all get routed together, including failover routing and other practices. So, it's usually best to "waste" an entire /24 on a single anycast service. Anycast is not exactly a cheap homebrew thing, so a /24 isn't _that_ much to use up.