Royal Pingdom: Theoretical vs real-world speed limit of Ping, shows the theoretical minimum ping between two furtherest places on the planet Earth, assuming everythings travel at the speed of light in vacuum.

If you choose the shortest route, the maximum distance between two locations will never be more than halfway around the planet. Halfway around Earth is about 20,000 km.

Considering that Ping goes to a destination and then back again, the packet sent by Ping would travel 40,000 km, the equivalent of a trip around Earth.

That is 133 milliseconds.

Anyone who has tried to ping various servers across the world will know that this is a way better response time than what you can realistically get. So why is ping so slow?

Then it summaries why in reality, the packet round trip time is much slower, because:

• The actual distance will be even lower because cables zig-zagging all over the place, not to mention light bounces along the inner-wall of fibre optics.
• Things rarely travels at the speed of light in vacuum. Light travels slower in glass, electrons are even slower, and devices like routers and repeaters don’t help.

Sounds like it is PHYSICS that prevents me from getting ultimate ping time to servers in the US, and there is almost nothing we can do about it! Oh wait, here are some proposed plans:

1. Create a worm hole between my house and that big data centre in Dallas, so I can plug my CAT5 cable right through to their switch.
2. Big data centres moving to Sydney, Australia.
3. Me moving to the States.

From the look of it, I think (2) is most probable. Sydney is such a nice place — good weather, good beaches and few natural disaster — don’t you think so? I am sure everyone would love to bring all their servers down here so I can have sub-20ms ping to all my favourite sites :)