Re: Internet Lines
- From: roberson@xxxxxxxxxxxx (Walter Roberson)
- Date: Thu, 14 Sep 2006 21:25:16 GMT
In article <1158264986.430119.96030@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
<ZooOYork@xxxxxxxxx> wrote:
We are looking to upgrade out data lines to the Internet. We currently
have three independent T1 lines and are having bandwidth issues that
We here have about 325 users and dedicate 2 full T1's to their internet
surfing as well as ingoing and outgoing email. We have a third T1 line
that is dedicated to our VPN to connect with our 40 or so small field
office. I am curious the amount of bandwidth other organizations have
as well as the number of users that supports and if this seems adequate
for their needs. I am considering a 12Mb fractional T3 as I received a
very good offer, but am concerned this is overkill
We vary... 175 to 250 users (but over 700 registered hosts in our tables!).
We have a gigabit service.
Our long term monitoring suggests that our average busy rate is
on the order of 64 Kbps, with 5-minute peaks up to 110 or so
but not particularily often. So, our monitoring statistics
suggest that we wouldn't suffer unduely by having merely 128 Kbps.
None the less, this analysis is not really detailed enough, as
in particular it does not deal with response time. When one of
our users interacts with an application at HQ, the response might
be a few megabytes (e.g., web page pictures), but the user is a lot
happier to have those squirted to them quickly (and then spend a
bunch of 'eye time' on them) then to have to wait for them to draw
before the 'eye time'. When the 'eye time' is included, the average
data transfer rate is not high -- and the monitoring tools aren't
fine-enough grained to pick out a several megabytes transfered quickly
and then eyeballed, compared to the same number of megabytes transfered
over 1 minute.
There have been a couple of occasions during which our interprovincial
link to HQ has dropped to 100 Mbit, which is still far faster than
our measured transfer requirements -- but people notice and do grumble.
Anyhow, check to see whether you can get "burstable fibre". That'd
probably be a fibre with a 100 Mbit modal bandwidth, rate-shaped to
whatever speed you are willing to pay for. If you are in a desired
business neighbourhood, the companies might install the fibre for cheap,
figuring to amoratize the costs over all the other nearby businesses
they think they can sell to. There might even already be fibre loop
running to within a couple of blocks. For one of the ISPs that
runs to our building, we traded install costs against space: they
put their local optical switching hub into our telecomms closet and
didn't charge us for fibre install.
Equipment to handle 100Base-LX is fairly inexpensive -- much less
so than to handle T3. And the price of 20 Mb burstable might only
be a fraction of the cost of a T3.
One disadvantage of burstable fibre compared to T1 or T3 is that
burstable fibre is shared at some aggregation point or other: you
are getting a link to "the internet", whereas T1 or T3 you can
go point-to-point. That used to make a big difference for
multimedia, but that's been more or less eliminated by better
compression and throwing bandwidth at the problem.
Another disadvantage is that the rates are not necessarily symmetric;
you might not be able to transfer outwards with burstable as quickly
as you can receive. Rate symmetry is important for some applications
and not important for others.
.
- References:
- Internet Lines
- From: ZooOYork
- Internet Lines
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