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A comparison of latency and throughput in telecommunications can address a common misunderstanding that having greater throughput means a "faster" connection. However, throughput, latency, the type of information transmitted, and the way that information is applied all affect the perceived speed of a connection. Image File history File links Information_icon. ... Shortcut: WP:WIN Wikipedia is an online encyclopedia and, as a means to that end, also an online community. ... Shortcut: WP:CU Marking articles for cleanup This page is undergoing a transition to an easier-to-maintain format. ... This Manual of Style has the simple purpose of making things easy to read by following a consistent format — it is a style guide. ... Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... In information technology, throughput is the rate at which a computer or network sends or receives data. ... Latency is a time delay between the moment something is initiated, and the moment one of its effects begins. ...

Terms

Main article: latency (engineering)

Latency is the delay between the initiation of a network transmission by a sender and the initial receipt of that transmission by a receiver. It is typically commensurate with the distance the signal must travel, but is also affected by delays introduced in network routing, including queues, multiple routes, packet loss, etc. and also Latency is a time delay between the moment something is initiated, and the moment one of its effects begins. ...

Main article: throughput

Throughput is the rate at which the transmission occurs. It is typically commensurate with the channel capacity of the lowest-bandwidth portion of the transmission conduit. In information technology, throughput is the rate at which a computer or network sends or receives data. ... Channel capacity, is the amount of discrete information that can be reliably transmitted over a channel. ... This article or section does not cite its references or sources. ...

Interplay of factors

Latency and throughput together affect the perceived speed of a connection. However, the perceived speed of a connection can still vary widely, depending in part on the type of information transmitted and how it is used.

For example, to view a web page over a 56 kbit/s modem transmitted from a server 4,800 km (~3,000 mi.) away, latency over the Internet is fairly low – typically about a quarter of a second – and an average web page of 30–100 kilobytes will transfer in 10–30 seconds. A 56 kbit/s line is a digital connection (possibly a leased line, possibly switched) capable of carrying 56 kilobits per second (kbit/s), the data rate of a normal single channel digital telephone line in North America. ... A modem (from modulate and demodulate) is a device that modulates an analogue carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... A mile is a unit of length, usually used to measure distance, in a number of different systems, including Imperial units, United States customary units and Norwegian/Swedish mil. ...

However, to transfer the contents of a DVD over a modem could take a week or more at this rate. Simply packing the DVD into an envelope and mailing it could be faster. DVD (commonly known as Digital Versatile Disc or Digital Video Disc) is an optical disc storage media format that can be used for data storage, including movies with high video and sound quality. ... In a non-network environment, the floppy disk was once the primary means of transferring data between computers. ...

Using a T1 line with similar latencies, one could download the same web page in under a second. To download a 5 GB DVD over this 1.5 Mbit/s connection would take about 7.4 hours. Digital signal 1 (DS1, also known as a T1) is a T-carrier signaling scheme devised by Bell Labs. ... A gigabyte (derived from the SI prefix giga-) is a unit of information or computer storage equal to one billion (short scale, meaning a thousand million) bytes. ...

External links

• It's the Latency, Stupid
• more formal paper by same author
• A technical article from Infocom 2001 on techniques for reducing web latency
  "As network technology becomes less dominated by bandwidth limitations, the round-trip times spent for protocol handshakes will become a dominant component in the overall transfer time" for many web pages.