PSINet/Cogent Latency

Phil Rosenthal pr at isprime.com
Tue Jul 23 02:28:01 UTC 2002


Actually, I wouldn't think about getting T1, DS3 or OC3 in the first
place ;)
Oc-12 is the minimum link I would even look at -- and my preference is
gig-e... Even if there is only 90 megs on the interface...

--Phil

-----Original Message-----
From: Alex Rubenstein [mailto:alex at nac.net] 
Sent: Monday, July 22, 2002 10:02 PM
To: Phil Rosenthal
Cc: nanog at merit.edu
Subject: RE: PSINet/Cogent Latency




On Mon, 22 Jul 2002, Phil Rosenthal wrote:

>
> I call any upstream link 'over capacity' if either:
> 1) There is less than 50mb/s unused

That must work well for T1's and DS3's.


> 2) The circuit is more than 50% in use

I call it 'over capacity' too, but that doesn't mean all the ducks are
in a row to get both sides to realise an upgrade is needed, and even if
they do realise it, to actually get it done. I am sure 2238092 people on
this list can complain of the same problem.

So, what do you do? You monitor it's usage, making adjustments to make
sure it doesn't get clobbered. You can easily run DS-3s at 35 to 40
mbit/sec, with little to none increase in latency from the norm. Many
people do this as well, even up to OC12 or higher levels all the time.




> I guess by my definition a DS3 is always 'over capacity'

Which must work very well for those DS3's doing 10 to 20 mb/s. Do you
upgrade those to OC3 or beyond?


-- Alex Rubenstein, AR97, K2AHR, alex at nac.net, latency, Al Reuben --
--    Net Access Corporation, 800-NET-ME-36, http://www.nac.net   --






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