Perhaps the first thing to consider is simply ramping up the bandwidth of the line technology you have now. But isn’t a T1 line fixed at 1.5 Mbps? Indeed it is. But that doesn’t mean you can’t have more than one T1 line. You don’t really want two separate T1 lines for point to point connections or dedicated Internet access. What you really want is a way to combine the bandwidth of those two lines so they act like one larger line.There’s a standardized process in place for doing this called bonding. When lines are bonded, their bandwidth is merged so that you don’t have to worry about which line is carrying the traffic. They both are sharing that traffic.
For copper technologies, bonding is also called pair bonding. That terminology comes from the fact that the physical layer of this network connection consists of twisted pair copper wires. These are the familiar telephone wires that are bundled in cables called binder groups and run from your business location to the nearest telephone company central office.
Copper pair can carry telephone calls or digital data. The old school way of transporting computer data was to use analog modems that converted the binary ones and zeros to audio tones to mimic a voice conversation. The upper limit to this approach is a very low bandwidth of around 56 Kbps. Get rid of the analog modems and transmit the digital signals on the copper wire directly and you can get much higher bandwidth.
T1 have been the mainstay of business bandwidth over copper pair. This line technology runs at 1.5 Mbps using two pair, one for transmit and one for receive. Since T1 was invented, more efficient modulation schemes have been devised that further increase the bandwidth that can be carried by twisted pair copper. These newer modulation techniques are now used to transport T1 on one or two copper pair. They can also be used to transport a competing technology called Ethernet over Copper.
Pair bonding will boost the bandwidth you can get over copper by pressing more pairs into service. It stands to reason that 4 pair should delivery more speed than 2 pair and 6 or 8 pair will boost that speed even more. It’s a lot like superhighways. The more lanes you have, the more traffic you can carry.
T1 and Ethernet over Copper bandwidths are not the same. T1 was invented first and intended to be synchronized with the public switched telephone system. It has a rigidly fixed 1.5 Mbps bandwidth per T1 line. You can bond a second T1 line and get twice the bandwidth, or 3 Mbps. Three lines gives you 4.5 Mbps, four will give you 6 Mbps and so on. T1 line bonding tops out around 10 or 12 Mbps. It’s hard to get more pairs to bond-in and it gets expensive. The cost of bonded T1 is the cost of a single T1 line (one or two pair) times the number of lines you have bonded.
Ethernet over Copper doesn’t have a fixed bandwidth. It varies with distance. The farther you are from the central office, the less bandwidth can be carried by this technology. The solution for higher bandwidth is to bond more pair. Typical EoC speeds are 2, 3, 5, 8, 10, 15, and 20 Mbps, with others often available. In some cases, Ethernet bandwidths up to 100 Mbps are available using bonded copper pair.
Since both T1 and EoC bandwidth is determined by pair bonding, how do you pick one over the other? The best way to make that decision is to get competitive bandwidth quotes for your exact location. Compare the bandwidth and price for each type of service and see which makes the most sense for you.
Note: Image of twisted copper pair courtesy of Wikimedia Commons.
