Another situation is the high technology business, such as a Wireless Internet Service Provider (WISP) or video production company. You may look at the 1.5 Mbps bandwidth spec on a T1 line and know you need twice that or several times. Now what do YOU do?
In many cases, the answer is simply to order more T1 lines. Yes, you can do that. Multiple T1 lines are not at all uncommon for larger or more demanding business applications.
Let's take a typical example. A small call center has a PBX system with a T1 line interface card. The T1 line is configured for ISDN PRI service. That gives them 23 outside lines with fast call switching and Caller ID for each line. Soon that call center gets more customers and finds that even with 23 lines they are running out of capacity. The answer is simply to order another T1 line configured the same way and get an additional 23 lines. Many modern PBX systems have the capability to handle 2 or more T1 lines on one or more interface cards.
A WISP finds that T1 dedicated Internet service offered enough capacity when they were getting started, but is now getting poky as more and more users sign-up. In this case the answer is to get 2 T1 lines bonded together. Bonding is a standardized way to combine the bandwidth of 2 or more lines so that they behave as one larger line. If you bond 2 T1 lines you get 2x the bandwidth or 3 Mbps. Bonding 4 lines gives you 6 Mbps and 6 lines gives you 12 Mbps.
So why order all these T1 lines instead of just getting a larger service? After all, DS3 will give you 45 Mbps, OC3 provides 155 Mbps, and Carrier Ethernet offers standard speeds of 10 Mbps, 100 Mbps and 1,000 Mbps.
There are good reasons to stick with T1 lines. First of all, you may want a service such as ISDN PRI telephone trunking that requires a TDM based service, not Ethernet. Or, you may want to start small and add bandwidth incrementally as your business grows. Most importantly, outside of major metropolitan areas you may find that it's T1 or nothing. T1 lines are provisioned on standard telephone trunk wiring, which is available just about anywhere. Higher bandwidth DS3, OC3 or Ethernet services may require fiber optic lines that are too expensive to install. That's especially true for wireless backhaul at WISP towers out in the countryside. T1 may be your only affordable solution.
What bandwidth solution is best for your company? It depends highly on where your business is located. Some areas have a wealth of competitive resources available. Others have only a few. The way to find out is to use the GeoQuote (tm) bandwidth search engine and see just what is available and at what cost.