Question

Ping RTT Europe->USA

Hi,

I'm not sure if this is the right forum for a question like this but I came across a strange phenomenon. I'm located in Germany. When I ping www.fbi.gov (104.16.79.187), I get an RTT of approximately 30ms. This seems way too fast from here to the USA since it would be 15ms one way, which could only cover about 4500km when assuming speed of light.

When I ping the same IP from http://www.t1shopper.com/tools/ping/ (server in LA), I get an RTT of <1ms (sometimes 8ms).

When I ping www.t1shopper.com from my home I get an RTT of about 170ms, which seems about right.

How can it be that a ping to 104.16.79.187 gives such a small RTT from LA as well as from my home?

Thanks.

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Comments
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Clarification Request
Ever cover in the classes what a CDN is?

There's no reason to not handle ping with the CDN.

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CDN and IP

Thanks for your reply. I've heard of CDNs but I haven't learned about them in detail. I always assumed that the selection of the actual server would work on the DNS level and that the Servers in the CDN still have different IP-addresses. Can you point me to a source where this is explained in detail?

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Just for clarification

I'm not sure if this was clear from my initial post but I always used ping 104.16.79.187 and not ping www.fbi.gov.

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With CDNs all over.

You can't be sure if your ping actually made the full trip.

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Another reason why.

Think about it. Trans-oceanic cables are best not cluttered with some traffic. Why not use CDN or similar gear to take out the "meaningless" traffic?

Post was last edited on September 20, 2018 10:32 AM PDT

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Yes but...

I understand that. But I thought that the way it works is that if I open www.amazon.com for example, the DNS server will tell me a different IP depending on where I am located. But I thought that the IP is still tied to a specific machine. Does this have to do with the IPv4->IPv6-translation? I still haven't found information online explaining how different servers in a CDN can reply to a single IP-address.

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