WebJunction

We are investigating options to upgrade our internet connection. Trying to determine how much bandwidth we need, and the best way to get it, is boggling my mind. I've read some messages here at WebJunction, but I'm still confused.

Wireless, DSL, and a T1 line are possibilites. No cable in our area. The online catalog/circ system requires a steady minimum 256K for each workstation; we will have 2, with hopes of a third in the future. In addition, there are 6 public computers, an office computer, and a catalog terminal (again with hopes for a second one).

How do I reasonably determine how much bandwidth we need? I'd rather overestimate than underestimate, but I have no idea how to go about it.

I am not sure that I am answering your question, but remember T1 is a measurement of bandwidth whereas DSL is a means of delivering that bandwidth. Depending on the available DSL service types in your area, you can often get greater than 1.544 Mbps (basically what people call a T1) or you can choose a different delivery mechanism, such as frame relay or a "leased line" that can give you less or more than a T1 also (aka a "fractional T1").

So, on to some questions for you that may help us provide some additional guidance to you on your questions -
1) do you need/want to allow access to internal resources (ILS, web server) from external sites? This could determine the level of connectivity you need and also possibly the type.
2) do you care / do you have the budget to pay for a higher or guaranteed level of service, such as a T1 or business-class DSL or would a consumer-grade of service suffice?
3) what is the price difference between the DSL and T1 in your area? Depending on the price difference and the other factors, this answer could make it a no-brainer.

If you want to just estimate, then the resource librarybob pointed you to is as probably as good as any. Most likely within two to three years anything you get will be maxed out (if not sooner), so depending on your timeline for the next upgrade and the amount of free time that you have available to answer this question, that may work for you.

If you want really precise to try to make sure that the estimate is as accurate as possible, then you will need to utilize some type of network analysis software.

If you want to know how much bandwidth the library uses on average, the best bet in my opinion is software like MRTG (http://oss.oetiker.ch/mrtg/). I am making a lot of assumptions in recommending it such as a level of technical expertise and existing equipment, so it may not fit your situation.

The other possibility is that your internet service provider runs something like this on their equipment and can provide such a report to you. Sometimes if you are lucky, they will provide it for free. If they are running similar software that might also be able to provide historical data.

There are other providers of similar tools - I have not tried them out, so cannot rec one way or the other, but a couple that look similar to MRTG and seem easier or about the same level to get up and running:
-Denika
http://www.somix.com/products/denika_free.php

-Intermapper
http://dartware.com/network_monitoring_products/index.html
(free five device license)

All of these assume that you either have or can set up SNMP on the device that connects to the internet.

Does that help at all?

We don't have our own server or any other internal resources to access. The online catalog, website, etc. are offsite. At this point in my research, a T1 line and business-class DSL are about $30 apart in monthly cost. Not so much different that one or the other is all that we can afford.

Right now, we are running one automated workstation and 6 computers (including the public ones) on 512K - which makes both the staff and patrons unhappy. The one thing we definitely know is that that is not working.

I was told that each automated system workstation requires a constant, steady 256K, not a connection that delivers bursts of bandwidth on demand. Is DSL "steady" or "on demand?"
We don't have the luxury of trying something out for a couple of months; we will have to commit to at least a year with either option.