I'm going to skip commenting on most of Dean's note and simply answer one of his questions that nobody else seems to have touched upon...
Now that I've done my homework, I'd like to hear comments from some of the more experienced folk here.
Glad to volunteer them. :-)
I haven't considered yet the maintenance/logistical cost of managing 15 T1s to 6 or 7 providers vs. the "ease" of two frac-T3s to two providers.
I would suggest you do so very soon; it will have a major impact on the way you conceptualize and design your operation. Keep in mind that a fractional T3 vs a T1 from most reasonably sized ISP's isn't that much different, typically around $1000/month for a T1 vs $3000 to $4000/month for a fractional T3 line. With the T1 lines, you're limited in how much data you can push out, and you don't really have any upgrade path as far as bandwidth goes. Also, keep in mind the routing issues involved with 15 T1's versus 3 T3's are VERY different; unless you have a VERY good routing guru locally, I wouldn't want to attempt juggling 15 T1's to different AS's as a first effort venture. :-)
From a provider's point of view, if a site wanted to connect, and was willing to sign a use-policy saying they wouldn't use the connection for transit to other providers (i.e. would only ask for customer BGP and only route to the nets you provide in BGP updates), would that site have lower costs associated with it? (that you could pass on?)
Of course! In fact, transit is a separate line item when you order; all you need to do is not ask for transit, and save the associated cost. Then all you have access to is our internal customers and backbone, we don't announce your routes out at all. Of course, I should have prefaced this by mentioning that I'm a network engineer, not a sales person, but since we're the ones that told sales how to sell this stuff... :)
Thanks, Dean
Matt Petach, speaking almost somewhat officially for InterNex Information Services (but just for this post!) mpetach@internex.net