In computer networks, bandwidth is used as a synonym for data transfer rate, the amount of data that can be carried from one point to another in a given time period (usually a second). Network bandwidth is usually expressed in bits per second (bps);
modern networks typically have speeds measured in the millions of bits per second (megabits per second, or Mbps) or billions of bits per second (gigabits per second, or Gbps).
Bandwidth is the range of frequencies, the difference between the highest-frequency signal component and the lowest-frequency signal component, an electronic signal uses on a given transmission medium. Like the frequency of a signal, bandwidth is measured in hertz (cycles per second). This is the original meaning of bandwidth, although it is now used primarily in discussions about cellular networks and the spectrum of frequencies that operators license from various governments for use in mobile services.
In business, bandwidth is sometimes used as a synonym for capacity or ability. In this sense, bandwidth usually refers to having time or staffing available to tackle something.
A T1 connection is a leased line generally used to connect companies or universities to the internet. It is recommended for connecting networks and Web servers with high-bandwidth requirements.
An E1 is the European equivalent of a T1 line. An E1 line has the greater throughput or data speed at (2.048 Mbps) than a T1 line as a result of less error checking.
A T3 connection is leased line operating in similar functionality to the T1/E1 lines. However, a T3 line has a total throughput 9data speed) of 44.74 Mbps, significantly greater than T1/E1.
An E3 line is the European equivalent of a T3 line. Like the E1, an E3 performs less frequent error checking and therefore can carry a throughput of 34.64 Mbps.
An OC-3 connection provides a throughput rate of 155.52 Mbps. It is sometimes used with ATM technologies.
xDSL, or Digital Subscriber Line, is a very high-speed connection (greater than 128 kbps) that uses existing copper wires and it is used primarily in the home and small business market.
