Common Questions About T1 Bandwidth: With Practical Answers
Confused about T1 bandwidth? There is no need to be more. Here are some of the most frequently asked questions…with practical answers to help you confidently use this backbone of business voice and data networks.
1. If the T1 data rate is 1.5Mb, why isn’t a cable service “same or better” that offers 6MB down/768Kb up? What are the fundamental differences between T1 and Cable?
Basically, the T1s are commercial connections. Cable/DSL services are typically residential.
T1s typically have:
* unlimited performance
* one guaranteed uptime per month
* no port blocking, allowing servers
* goes up 2-5 times higher than cable/DSL
* faster repair times, since the company will most likely have priority to repair them
* a dedicated line
Cable/DSL typically has an AUP or TOS that doesn’t allow servers and can have high downtime. Also, when there is no internet, there may be no business either.
Cable/DSL has fast download speeds, but in a business setting, you might just be checking email/browsing the web/updating database records, so you don’t need as many downloads. However, you may be running a server that loads a lot, or you may be updating a website and need to send files frequently. Charging a T1 helps in this setup.
Raw maximum speed is not all there is to a connection. T1 is marketed as an enterprise class service. That means it’s symmetrical, making servers easy to run, and it comes with a service level agreement that guarantees minimum acceptable performance and mean time to repair (MTTR). These are critical components in marketing different services. If you’re a business, the cost of a network outage could be dramatic.
That being said, the widespread availability of very low-cost residential services is putting enormous pressure on the prices of traditional business-class services. With that, you see that the cost of T1 lines (as well as DS3 and even OC3) has steadily decreased over the last year.
2. Is T1 more than raw bandwidth? Is voice T1 fundamentally different from data T1 for Internet access or “integrated T1” for voice and Internet access? If you need voice, do you have to go with a telco T1 type provider that can give you DID and local service, long distance, etc.? When people talk about “integrated T1” that can be used for Internet access (data) and telephone service (voice), how does the provider handle the data side and the voice side?
Simply put, T1 is a point-to-point link. T1 was developed in the late 1960s to carry 24 digitized telephone calls between telephone switching offices. Think of T1 as a simple pipe, between you and the service provider. That service provider can be the phone company that provides voice service over the T1 pipe, or an ISP that provides Internet access. The T1 line doesn’t care how the bits are used, bit-is-bits. If you want DID trunks, you need to make sure that the remote end of T1 connects to a service provider capable of delivering them.
Remember the story of T1.
It was designed to carry digital phone calls. The total capacity is divided into 64 kbps channels. That’s great for voice, but doesn’t make sense for data, so the data uses unchannelized T1. In the middle is that ability to mix and match data and voice. Hence the birth of the “integrated T1” lines.
3. In “integrated T1”, voice calls have priority. In the absence of voice calls, full bandwidth is available for Internet access. How is “dynamic and automatic” bandwidth allocation done? Do you need special edge equipment to do this?
T1 is just a pipe. It is very simple to have equipment at each end of the T1 that dynamically assigns voice as high priority and data on a best effort basis on a single T1 pipe, the common term is Integrated Access Device (IAD).
There You Go You now have the basic knowledge needed to make the initial informed decisions about installing a T1 line for your company’s voice/data network. For more complex applications, I suggest using the services of a free consultant to guide your business through potential minefields.
