What Is A DS-3?

Answer:
A DS-3 is a type of high speed data line

which is used to connect two sites. Typically, this type of line is used to connect between carriers. Except in very large environments with many sites, it would be rare to see a DS-3 deployed in a corporate environment. DS-3 stands for Digital Signal 3.

A DS-3 line is equal to 28 T-1 lines, and functions at a theoretical speed of 44.736 million bits per second. They have the capability of transferring very large databases over wide area networks and they also have the capability to handle 672 simultaneous phone (voice) conversations. Physically, they are typically fiber over long distances with coax cable completing the last mile, although there are exceptions to the rule. Fiber has limited availability throughout the United States, with copper being the most common line available. Because of this, very expensive infrastructure expenses are often incurred in order to get full DS-3 access.

In North America, a DS-3 translates to a T-3, which is equivalent to 28 T-1 lines, where each T-1 line operates at 1.544 Mbps. All of the 28 T-1 lines are multiplexed through an M13 (Multiplex 1-to-3 multiplexer), and 188 additional signaling and control bits are added to each T-3 frame. Each frame is transmitted 8,000 times per second, so the total T-3 signaling rate is 44.736 Mbps. When broken into channels, a T-3 will support 672 channels where each is 64 Kbps. In Europe, a DS-3 translates to an E-3, which runs at 34.368 Mbps, has support for 480 channels, and is equal to 16 E-1 lines.

If you are sending a DS-3 between continents, the networking standards of the target country will set the rules. Channels will get translated, and signaling conventions will get translated as well. In the United States, T-1s contain 24 channels of 64 Kbps each (1.544 Mbps), whereas in the United Kingdom, an E-1 will contain 30 channels of 64 Kbps each (2.048 Mbps).

Companies who typically will use a DS-3 will include companies that host high traffic web sites, companies that perform web hosting, companies that require high bandwidth, universities/colleges, government offices, and high volume call centers. Depending on the business requirements, a full DS-3 can accommodate a lot of simultaneous users. A DS-3 is usually installed as a main network channel for a large corporation. It is an always on, high speed connection that will provide a very stable and reliable link either to corporate offices or the Internet, and the line can support over 500 users.

If you do not need a full DS-3 now, but expect your bandwidth needs to grow, you can also get a tiered DS-3, where channels are opened up as they are needed, until all channels are active.