What is Throughput?

Throughput is a measurement of the rate of data transfer through a network. Often erroneously referred to as bandwidth, throughput is a combination of the limiting factors of device latency, the speed of the data transfer medium, and the distance between points on the network. High-throughput connections are often mistakenly called high-speed connections, a term that implies that data moves from one location to another location quickly. While this may seem to be the case when transferring large files, the truth of the matter is that large amounts of data can be transferred over high-throughput connections, but not any more quickly than the speed of low-throughput connections. This is analogous to a bus carrying many passengers and a motorcycle carrying only one. The motorcycle may be faster, but the bus can move large groups of people in less time than the motorcycle.

Although different networking technologies do in fact transfer data at different speeds, the difference between them is negligible. Importantly, the different speeds have almost no effect on the throughput of the medium, and therefore slower mediums can in fact have higher bandwidths. Light travels through fiber optic cable at about two-thirds it's speed in a vacuum, or about 1.92e8 meters per second. Data flowing through fiber optic cables travels at exactly this speed. The average drift velocity of electrons flowing through copper wire is about 4.62e-3 meters per second, a bit faster than a snail on a good day. However, although the electrons themselves are moving slowly, copper wire can transfer data at up to 1.8e8 meters per second. This is almost the same speed as fiber optic cable, due to the speed at which the electric field spreads across the wire. One would assume then that copper wire's lower speed would translate into lower throughput, however this is not the case. Copper wire can exceed the throughput of a comparable length of fiber optic cable, depending upon other factors such as modem compression and latency. Thus, terms such as "high speed" are misleading, as networking technologies that have high speeds of data transfer may in fact provide lower throughput and less bandwidth.