You're familiar with choke points in the physical world. Try exiting a superhighway onto a busy local street during rush hour. Try filling a swimming pool from the city water mains using a garden hose. Anytime a high capacity conduit is connected to a low capacity conduit things are going to slow down.
This isn't always a problem. You can get off the freeway onto a deserted country road with nothing to impede your progress. You water your plants with a garden hose and have to restrict the nozzle to prevent overwatering. As long as the lower capacity conduit has more capacity than you require, it's not a restriction.
That used to be the way business Internet connections worked. A company that wanted to initiate Internet service for its employees would install a dedicated T1 connection to its corporate network. When the Internet was new, most people weren't sure what to do with it. Then, gradually, traffic picked up from a growing number of email users and those who found it faster to do a Web search than go to the reference library. Sooner or later, demand exceeds supply and your Internet connection becomes a choke point.
What's so bad about letting supply and demand work themselves out? In the case of WAN choke points, there's potentially a big productivity loss involved as people wait for pages to load or files to transfer. If you have a group collaborating on a project and they need to all view and markup large CAD drawings, you can multiply the size of the group by the seconds or minutes lost times what you are paying them to see how much this costs.
You have the choice of either getting people to change their work habits to deal with bandwidth restrictions or simply increase the bandwidth. Yes, much of the time there is a cost increase involved. You may need to compare the cost of a faster line with the gain in productivity to justify this expense. If enough people are slowed down enough by the speed restriction, those losses add up faster than you might think.
So what can you do? An easy solution is to incrementally add more bandwidth. If one T1 line isn't enough anymore, bond in a second T1 line or a third. If you need a larger increase in bandwidth, consider a DS3 connection or perhaps one of the new Metro Ethernet services.
Don't automatically assume that you'll pay a lot more to ease that WAN choke point. Competitive line prices have come down dramatically in the last few years. If you have an older contract or haven't used a tool such as GeoQuote (tm) to find the best prices, you may be surprised to find that you can get more bandwidth for the same or less money than you are now paying.
