Re: 50Mb across the country in 6 seconds

Hello Friends! I hope this finds you all doing well.

Hummm ... an interesting question. A 1Gig link is the max, however the
latency and window sizes will play into this. The the old rules for actual
bandwidth is determined by the WS and RTT ...

Here is the formula for determining the max theoretical speed:

BW = WS / RTT (Another way of stating this; BW equals the WS divided by the
RTT) - Does the DBA know what WS for the apps, is this TCP, and I assume
the latency is about 30msec one way?

WAAS and other newer technologies breaks all these rules!!! and most apps
run better today besides, they are more likely to use the bandwidth they
have available to them ... TCP spoofing, using large window sizes, packet
agg, jumbo frames, etc ...

Is this an UDP copy program? If so, it would be faster ...

After these types of concerns, and tricks and tweaks, you still have drive
speeds to slow you down, etc ...

Interesting posting on iperf I found, relevant to this discussion:
http://sourceforge.net/apps/phpbb/freenas/viewtopic.php?f=62&t=423

These folk are getting speeds enough to accomplish what you mention...

Why is this not possible? Sounds possible to me ...

Jersey guy, we are all interested to hear what you find out!!!

Do please have a good day!!!
Andrew Lissitz

On Sat, Mar 3, 2012 at 3:22 PM, James Poplawski <jb.poplawski_at_gmail.com>wrote:

> WAAS?
>
> Sent from my iPhone
>
> On Mar 3, 2012, at 11:57 AM, Jersey Guy <guy.jersey_at_gmail.com> wrote:
>
> > Hello Gents. This DBA guy tells me he copied a 50Mb file from his machine
> > in New Jersey to a server in California in 6 seconds. I told him that's
> not
> > possible because the smallest link in the path is 1Gb/sec but MTU is
> 1500,
> > so even if you take wire speed, it would be at least 33 seconds before
> the
> > file was copied. Am I wrong in saying so?
> >
> > TIA
> >
> >
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-- 
Andrew Lee Lissitz
all.from.nj_at_gmail.com
Blogs and organic groups at http://www.ccie.net