have 850 computers with two E1 for 4Mbs full=20
duplex. We almost ground to a halt during the=20
day. For a temporary fix that wasn't too=20
expensive, we got four 12Mbs cable modems,=20
bundled them together, and added an inexpensive=20
load-balancing router. We route mission critical=20
applications (defined as anything we pay for)=20
through our E1 lines and have everything else come down the cable modems.
A few caveats:
1. Business class cable is outrageously expensive=20
and slow here, so the cable modems are just=20
ordinary residential modems using the company's=20
residential service--and they only have a 10%=20
service guarantee. (That's essentially a worthless guarantee.)
2. We tried to load balance in our Cisco router,=20
but it turns out that was not possible because=20
the modems had IPs in the same subnet, which is=20
prohibited by design. Since we weren't doing=20
business cable, we couldn't get fixed IPS.
3. When our cable provider had problems, we had to switch back temporarily.
4. We exceeded the download allotment for the=20
modems at the end of April and were throttled=20
back for the last few days of the month.
There were a few other technical issues that we=20
had to overcome, such as forcing port 443 through=20
one cable modem as some websites require SSL=20
sessions to maintain the same IP for the=20
duration, and routing port 1863 (MSN messenger)=20
through our E1 so that it didn't sign in every five minutes.
Overall, it's been a success. Instead of seeing=20
our bandwidth peg at 4Mbps and stay there through=20
the day, we average 6 to 8 Mbps, with peaks of 30=20
Mbps.. Next year, when we rewrite our E1=20
contracts, we will be able to get 12Mbps for=20
cheaper than our current 4, and then we will use=20
2 16Mbps cable modems with fixed IP and 90%=20
service quality guarantee for other surfing. In=20
that case, if either one service or the other=20
goes down, we will still be able to access our services.
Derrel
_________________________________________________________
Derrel Fincher
Director of Information and Communication Technology
Graded=96The American School of S=E3o Paulo
(Associa=E7=E3o Escola Graduada de S=E3o Paulo)
Av. Pres. Giovanni Gronchi, 4710
S=E3o Paulo, SP, 05724-002, Brazil
http://www.graded.br |T:+55-11-3747-4837
_________________________________________________________
At 07:05 PM 6/9/2009, Renee Ramig wrote:
>Our school has been pretty loose about letting teachers, administrators
>and staff use the computers for personal use on their own time (prep,
>recess, lunch, after school, etc.). However, with applications and web
>2.0 sites taking more and more bandwidth, I have a need for teachers to
>stop streaming their radio station, stop watching the news videos, stop
>checking their Facebook, stop shopping for a new pair of shoes, etc.
>especially during school hours. I doubled the bandwidth this year from
>one T1 to two T1s for about 300 computers, and there are times when max
>bandwidth is being used for hours at a time, even though I know very few
>if any students are using it at that time.
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