How Many MBPs Is a Fast Internet?

by David Dunning

Fast Internet, more appropriately known as Fast Ethernet, refers to several Institute of Electrical and Electronics Engineers (IEEE) 802.3 standards for local area networking, which provide data transfer rates of up to 100 megabits per second (Mbps). Fast Ethernet, otherwise known as 100BASE-T, provides a tenfold increase in data transfer rate when compared with the original Ethernet standard, otherwise known as 10BASE-T.


Mbps is an abbreviation for megabits per second, a unit of network speed, or bandwidth, which is typically used to describe the upload and download speeds of an Internet connection. A megabit is strictly 2^20 or 1,048,576 bits, but the term is often used to mean exactly 1 million bits. The upload speed refers to the speed at which data is sent from the user to the Internet, while the download speed refers to the speed at which data is sent from the Internet to the user. Most Internet users download more data than they upload, so download speed is typically more important than upload speed.


The Fast Ethernet family of technologies includes 100BASE-TX, which uses two twisted-pair copper cables; 100-BASET4, which uses four voice-grade, twisted-pair cables; and 100-BASEFX, which uses optical fiber links. Fast Ethernet was introduced in 1995 and was, indeed, the fastest version of Ethernet until the advent of so-called gigabit Ethernet -- which offers a data transfer rate of up to 1 GB per second (Gbps) over optical fiber or short copper links -- in 1998.


Computers with a 10BASE-T network interface card can connect to a Fast Ethernet network but are limited to a data transfer rate of 10 megabits per second. The Fast Ethernet specification actually includes mechanisms for the automatic negotiation of data transfer speeds, so some vendors provide dual-speed network interface cards that can run at 10 Mbps or 100 Mbps automatically, depending on the network to which they are connected.

Data Frame

An Ethernet data frame is a short, manageable method of describing data to be transmitted across a network. The IEEE 802.3 standard defines a minimum data frame size of 64 bytes and a maximum data frame size of 1,518 bytes for Fast Ethernet. The data section of the data frame is occupied by between 46 and 1,500 bytes of data. The remainder of the frame is made up by sections containing a start-of-frame delimiter, source and destination address information, which identifies the computer that sent the frame and those that should receive it, and synchronization and error-checking information.

About the Author

A full-time writer since 2006, David Dunning is a professional freelancer specializing in creative non-fiction. His work has appeared in "Golf Monthly," "Celtic Heritage," "Best of British" and numerous other magazines, as well as in the book "Defining Moments in History." Dunning has a Master of Science in computer science from the University of Kent.