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I hope the question made sense how I worded it. :)

I've been wondering, maximum theoretical bandwidth is measured as RWIN/RTT (Window size / round trip time)

So if a major city only 100 miles away gives me a ping of 50ms, and I have the default 64kb TCP window size then my maximum throughput will be 12.5Mb/s. Everything further away would give me a higher ping and therefore a lower throughput.

Is there any reason to buy something like FiOS with a 50Mb/s or greater connection? Will you ever be able to reach that kind of speed?

I know you can increase the TCP window size to increase throughput, but it has to be at both ends which is a deal breaker because you can't control the server.

I'm assuming other network protocols like UDP aren't quite as affected by latency as TCP is, but how much of overall network traffic does non-TCP make up vs TCP.

Am I just misguided about how throughput works? But if the above is correct, then why should a consumer like me buy way more bandwidth than can be realistically used. Maybe the only reason is for downloading multiple things at once, or one thing from multiple servers/peers?

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closed as off topic by Ƭᴇcʜιᴇ007, slhck, Diogo, Nifle, random Jul 11 '12 at 23:08

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You can use multiple conncetions. So, in a home with 10 devices, each pulling 5mbps, you saturate your connection –  Akash Jul 1 '12 at 7:23
Or, even multiple conncetions from the same device. Say, windows update while youtube streaming and making a skype call? –  Akash Jul 1 '12 at 7:24
Why buy a car that can do 180 MPH? –  Daniel R Hicks Jul 1 '12 at 12:09

2 Answers 2

up vote 1 down vote accepted

Support for windows over 64KB is more than 20 years old. It's supported by pretty much every server you're likely to care about. Even most mobile devices support window scaling.

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Also, what if you want to connect to more than one server at once? It's common for many web pages to serve elements of that page from multiple servers. –  ultrasawblade Jul 1 '12 at 11:54

Don't buy more bandwidth than you need.

Also, you are probably getting way more upstream with that connection than what is available from your cable or DSL company. If you run services on your machine at home and spend a lot of time connecting to your home systems from remote locations, this is a significant advantage, even if you never use all the downstream.

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