T1 speed drops from one download?

[lance70]

Hi, I work for a small company with anywhere from 10 to 15 people in the office. The owner purchased a T1 line about 6 months ago and we are an engineering firm. So we have one customer we must use a vpn to access their system and we have a router configured for that. We also pull down a lot of auto cad drawings. Question is should the T1 speed drop from just one person downloading?
I will get about 1.45 in the morning and if someone comes in and opens up their e-mail and starts to download a 10Mb attachment the speed actually drops to .29 or lower,that's from one person being on it, is this normal?

 

[MikeHalloran]

No, that's from at least two people being on it; you and the downloader, and probably a couple more who sent an email or just looked at a remote directory.

AFAIK, T1 lines are shared among all current or recent users; everyone who's already on loses some bandwidth when someone new gets on, and your allocation may not go up just because other users are not currently transmitting or receiving.

T1 is great for text transactions and such. It's nowhere near satisfactory for working with CAD files.

 

[lance70]

Thanks! What would you suggest for CAD drawings or could we set this up different and use cable or DSL with the T1?

 

[MikeHalloran]

I think you can set up a vpn over dsl or cable, but it may enter the customer's site on a T1 anyway, so there may not be a gain to be had.

The most usable way to share CAD data over a distance is via optical fiber. For a couple of blocks, you may be able to string your own; for longer distances, you'll probably have to lease it. There's a lot of fiber already strung along pipelines, but it may still be priced as if they had to put it in just for you.

Another option that may be attractive is to set up a local server as a doppelganger of the client's CAD system, so files are automatically synchronized in the background, perhaps overnight, via the T1 line. Such a setup might interfere with the client's PDM system, if one is in use. If not, you can expect occasional collisions where two people have revised the same drawing in the same time period, and you may lose one set of revisions.

Your local AutoCAD dealer/VAR has probably encountered the same problem with other customers, and may be able to suggest a better solution.

 

[SYQUEST]

You can get more bandwidth by using a bonded DS1 arrangement, using more DS1s, if you don't have fiber entrance facilities. Who is you ISP? You might want to contact them and find out what is available and costs. There are reasonable options out there, but it takes a little research.

You might want to verify that your service is working correctly using on of the speed test sites:

http://www.dslreports.com/speedtest?more=1

That way you will have some idea that you are getting what you are paying, and working correctly.

....JIM....