Downstream (computer science)
Encyclopedia
In a telecommunications network
or computer network
, downstream refers to data sent from a network service provider to a customer.
Although the best voiceband
modems are called 56 kbit/s modems, downstream speeds can be limited to a few tens of kilobits per second with even lower upstream speeds. Asymmetric Digital Subscriber Line
(ADSL) and cable modem
s, two popular Internet access
technologies, greatly improved downstream speeds reaching several Mbit/s. Mobile broadband
and satellite Internet access
providers also often have lower upstream speeds than downstream.
One process sending data primarily in the downstream direction is downloading.
However, the overall download speed depends on the downstream speed of the user, the upstream speed of the server, and the network between them.
In the client–server model, downstream can refer to the direction from the server
to the client
.
Telecommunications network
A telecommunications network is a collection of terminals, links and nodes which connect together to enable telecommunication between users of the terminals. Networks may use circuit switching or message switching. Each terminal in the network must have a unique address so messages or connections...
or computer network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
, downstream refers to data sent from a network service provider to a customer.
Although the best voiceband
Voiceband
In electronics, voiceband means the typical human hearing frequency range that is from 20 Hz to 20 kHz. In telephony, it means the frequency range normally transmitted by a telephone line, generally about 200–3600 Hz. Frequency-division multiplexing in telephony normally uses...
modems are called 56 kbit/s modems, downstream speeds can be limited to a few tens of kilobits per second with even lower upstream speeds. Asymmetric Digital Subscriber Line
Asymmetric Digital Subscriber Line
Asymmetric digital subscriber line is a type of digital subscriber line technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice...
(ADSL) and cable modem
Cable modem
A cable modem is a type of network bridge and modem that provides bi-directional data communication via radio frequency channels on a HFC and RFoG infrastructure. Cable modems are primarily used to deliver broadband Internet access in the form of cable Internet, taking advantage of the high...
s, two popular Internet access
Internet access
Many technologies and service plans for Internet access allow customers to connect to the Internet.Consumer use first became popular through dial-up connections in the 20th century....
technologies, greatly improved downstream speeds reaching several Mbit/s. Mobile broadband
Mobile Broadband
Mobile broadband is the marketing term for wireless Internet access through a portable modem, mobile phone or other mobile device.-Description:...
and satellite Internet access
Satellite Internet access
Satellite Internet access is Internet access provided through satellites. The service can be provided to users world-wide through low Earth orbit satellites. Geostationary satellites can offer higher data speeds, but their signals can not reach some polar regions of the world...
providers also often have lower upstream speeds than downstream.
One process sending data primarily in the downstream direction is downloading.
However, the overall download speed depends on the downstream speed of the user, the upstream speed of the server, and the network between them.
In the client–server model, downstream can refer to the direction from the server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
to the client
Client (computing)
A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....
.