Current trends in capacity planning and oversubscription

Frank Bulk frnkblk at iname.com
Sat Nov 13 21:54:12 CST 2010


I've been tracking Internet bandwidth usage for several schools (RESNET-L
reports), and I've seen it as low at 2.1 kbps/FTE (5+ years ago) to higher
than 300 kbps/FTE.  Most of the schools are between 30 to 60 kbps/FTE at
this time.  Very broadly speaking, rural and smaller schools are on the low
end, while state schools with tens of thousands of students are on the
higher end. Internet2 plays in the mix as well.

In terms of growth rates, while our ISP serves only one college, even though
they've been growing their bandwidth pipe at low-double digits per year,
they are maxed out most days from mid-day to 1 am.  If most ISPs see
end-user traffic grow 50 to 80% per year, I can't see why schools would be
much out of that range.

Frank

-----Original Message-----
From: Sean Donelan [mailto:sean at donelan.com] 
Sent: Friday, November 12, 2010 5:52 PM
To: NANOG list
Subject: Re: Current trends in capacity planning and oversubscription

On Wed, 10 Nov 2010, Curtis, Bruce wrote:
>  If we take our current ISP bandwidth and increase it by 50% every 
>year for 5 years it would be about twice the 100 Mbps per 1,000 
>students/staff recommendation.

Is 50% growth each year typical these days?  In the dot-com boom days, 
people said 100% growth, other people have suggested 20% may be more 
reasonable now.  A problem with government network capacity 
planning/growth forecasts is you will be stuck with whatever you choose, 
too high or too low, for many years because the budget cycle is so long.

It would be great if there was some actual data available.  But it seems
more typical to benchmark/compare to do network capacity planning with 
other government agencies, so we end up with X-Mbps per Y,000 people.
Yes, I know it depends.  1,000 people downloading data from LHC 
experiments will be different from an administrative school office. 
The difference is the people using LHC data usually have someone who can 
figure out network capacity planning, while the people in an 
administrative school office may not have anyone.

So what is a reasonable network capacity for 1,000 students now and in 5 
years.






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