Communications
When does a T1 make sense?
Should I get a T1? Should I get rid of my T1?
There are a lot of common misconceptions about T1s. The biggest one being that they are fast, they’re not. However a T1connection is more than just a antiquated form of broadband. There is a lot a T1 can do you for and your business, as long as you understand it’s limits.
Firstly, what is a T1?
T1s have been around since the 50s. Simply speaking they are essentially 24 phone lines wrapped together in “trunk” or a “backbone”. They have been used as backbones to connect entire neighbourhoods, or large companies. As time went on and computers became more common it became necessary to connect distant locations together. At first it became common to use a T1 to connect serial terminals over long distances to a “mainframe”. Whole rooms of Teletype machines could be powered by one T1. However eventually the Internet came along and the T1 evolved again.
As many of you may recall sitting in front of your Computer running Windows 95 and AOL6, an average dial-up modem connects at around 56kbps kilo bits per second (one byte is eight bits). A T1 is very similar, each one of the voice channels in a T1 trunk is equivalent to about 64 kbps of data. For some of you that remember ISDN, it’s the exact same circuit expect scaled up. When you take these 24 voice channels and you multiple them by 64kbps, factor in 8 kbps of framing information and you get approximately 1.544mbps (megabits per second) or 1,544 kbps. And that is exactly how much bandwidth up and down you can expect to get from a T1.
How much bandwidth is 1.544mbps?
At one time it was a vast amount, enough to power an entire office of green screens running MS-DOS, or a whole community college. Unless you could justify the then high cost of a T1, it wasn’t worth it. However, now a days the average Cable modem downloads at above 8 mbps. Even cheap basic DSL usual can download at around 1 or 2 mbps. Although typical residential Broadband has less upload bandwidth then a typical T1 (around 600-1000kbps compared to 1544kbps), many commercial packages start at 1.5mbps and go up well past 2mbps.
So then what’s the point?
There are a few things that a T1 can do for you that Cable or DSL can’t. Firstly, the beauty of a T1 is that it’s both phone AND data. If you have more than 8 phone lines coming into your office chances are after taxes your bill is getting very rotund. Most of the cost of a T1 is fixed, this means that the price difference between 5 lines and 15 is minimal once you already have the connection, and you can use the left over channels for data. Although there are a number of ways to configure a T1, essentially you can configure your T1 so that when you’re not on the phone, you get more bandwidth. Since each voice channel represents 64kbps, you can get bandwidth back when it’s not being used.
Service Level Agreements
Another benefit is the reliability of a T1. Very few other types of connections will guarentee you a certain degree of reliability. For T1s this is typically called a “Service Level Agreement”. Essentially it gaurentees a few things.
1. If your connection goes down, a technician will be on-site within a certain time frame.
2. You will be guarenteed a certain amount of bandwidth at all times.
3. A certain latency, meaning time it takes to get data from your office, to theirs.
Although these may seem trivial, anyone who has waited through a five hour Comcast window when their business has grinded to halt knows that a SLA is well worth the money.
Reliable Back Up or Secondary Internet
Yes, I said it BACKUP Internet. A T1 is not enough for the average business. 1.544 mbps down is just not sufficient for most offices who actively use the internet as part of their business. It comes out to about 193 KB/s (kilobytes per second). This number may be plenty for one person, but as the number gets divided more and more, it can become frustrating. Internet applications are demanding more and more bandwidth all the time. Office’s that rely on T1s often times fall into this trap.
A common question I get is: “Why is the Internet so slow, we have a T1, that’s really fast, isn’t it?”
Answer: Yes, it used to be.
Now alas, here comes the good part. You can mix the reliability of your T1, with the Speed of your Cable Modem. I introduce to you, the Load Balancing Router.