Bandwidth (computing) in the context of Conventional PCI

Consumer IR, consumer infrared, or CIR is a class of devices employing the infrared portion of the electromagnetic spectrum for wireless communications. CIR ports are commonly found in consumer electronics devices such as television remote controls, PDAs, laptops, computers, and video game controllers.

The functionality of CIR is as broad as the consumer electronics that carry it. For instance, a television remote control can convey a "channel up" command to the television, while a computer might be able to surf the internet solely via CIR. The type, speed, bandwidth, and power of the transmitted information depends on the particular CIR protocol employed.

Optical networking is a means of communication that uses signals encoded in light to transmit information in various types of telecommunications networks. These include limited range local-area networks (LAN) or wide area networks (WANs), which cross metropolitan and regional areas as well as long-distance national, international and transoceanic networks. It is a form of optical communication that relies on optical amplifiers, lasers or LEDs and wavelength-division multiplexing (WDM) to transmit large quantities of data, generally across fiber-optic cables. Because it is capable of achieving extremely high bandwidth, it is an enabling technology for the Internet and telecommunication networks that transmit the vast majority of all human and machine-to-machine information.

An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss and are immune to electromagnetic interference. Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, such as fiber optic sensors and fiber lasers.

Glass optical fibers are typically made by drawing, while plastic fibers can be made either by drawing or by extrusion. Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers, while those that support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,050 meters (3,440 ft).

In telecommunications and computer networking, a network packet is a formatted unit of data carried by a packet-switched network. A packet consists of control information and user data; the latter is also known as the payload. Control information provides data for delivering the payload (e.g., source and destination network addresses, error detection codes, or sequencing information). Typically, control information is found in packet headers and trailers.

In packet switching, the bandwidth of the transmission medium is shared between multiple communication sessions, in contrast to circuit switching, in which circuits are preallocated for the duration of one session and data is typically transmitted as a continuous bit stream.

Comfort noise (or comfort tone) is synthetic background noise used in radio and wireless communications to fill the artificial silence in a transmission resulting from voice activity detection or from the audio clarity of modern digital lines.

Some modern telephone systems (such as wireless and VoIP) use voice activity detection (VAD), a form of squelching where low volume levels are ignored by the transmitting device. In digital audio transmissions, this saves bandwidth of the communications channel by transmitting nothing when the source volume is under a certain threshold, leaving only louder sounds (such as the speaker's voice) to be sent. However, improvements in background noise reduction technologies can occasionally result in the complete removal of all noise. Although maximizing call quality is of primary importance, exhaustive removal of noise may not properly simulate the typical behavior of terminals on the PSTN system.

Fiber-optic communication is a form of optical communication for transmitting information from one place to another by sending pulses of infrared or visible light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference is required. This type of communication can transmit voice, video, and telemetry through local area networks or across long distances.

Optical fiber is used by many telecommunications companies to transmit telephone signals, internet communication, and cable television signals. Researchers at Bell Labs have reached a record bandwidth–distance product of over 100 petabit × kilometers per second using fiber-optic communication.

Web traffic is the data sent and received by visitors to a website. Since the mid-1990s, web traffic has been the largest portion of Internet traffic. Sites monitor the incoming and outgoing traffic to see which parts or pages of their site are popular and if there are any apparent trends, such as one specific page being viewed mostly by people in a particular country. There are many ways to monitor this traffic, and the gathered data is used to help structure sites, highlight security problems or indicate a potential lack of bandwidth.

Not all web traffic is welcomed.Some companies offer advertising schemes that, in return for increased web traffic (visitors), pay for screen space on the site.

A modulator-demodulator, commonly referred to as a modem, is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by modulating one or more carrier wave signals to encode digital information, while the receiver demodulates the signal to recreate the original digital information. The goal is to produce a signal that can be transmitted easily and decoded reliably. Modems can be used with almost any means of transmitting analog signals, from LEDs to radio.

Early modems were devices that used audible sounds suitable for transmission over traditional telephone systems and leased lines. These generally operated at 110 or 300 bits per second (bit/s), and the connection between devices was normally manual, using an attached telephone handset. By the 1970s, higher speeds of 1,200 and 2,400 bit/s for asynchronous dial connections, 4,800 bit/s for synchronous leased line connections and 35 kbit/s for synchronous conditioned leased lines were available. By the 1980s, less expensive 1,200 and 2,400 bit/s dialup modems were being released, and modems working on radio and other systems were available. As device sophistication grew rapidly in the late 1990s, telephone-based modems quickly exhausted the available bandwidth, reaching 56 kbit/s.

Uploading refers to transmitting data from one computer system to another through means of a network. Common methods of uploading include: uploading via web browsers, FTP clients, and terminals (SCP/SFTP). Uploading can be used in the context of (potentially many) clients that send files to a central server. While uploading can also be defined in the context of sending files between distributed clients, such as with a peer-to-peer (P2P) file-sharing protocol like BitTorrent, the term file sharing is more often used in this case. Moving files within a computer system, as opposed to over a network, is called file copying.

Uploading directly contrasts with downloading, where data is received over a network. In the case of users uploading files over the internet, uploading is often slower than downloading as many internet service providers (ISPs) offer asymmetric connections, which offer more network bandwidth for downloading than uploading.

In computing, computer performance is the amount of useful work accomplished by a computer system. Outside of specific contexts, computer performance is estimated in terms of accuracy, efficiency and speed of executing computer program instructions. When it comes to high computer performance, one or more of the following factors might be involved:

• Short response time for a given piece of work.
• High throughput (rate of processing work tasks).
• Low utilization of computing resources.
  • Fast (or highly compact) data compression and decompression.
• High availability of the computing system or application.
• High bandwidth.
• Short data transmission time.

A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. It often uses a computer network to spread itself, relying on security failures on the target computer to access it. It will use this machine as a host to scan and infect other computers. When these new worm-invaded computers are controlled, the worm will continue to scan and infect other computers using these computers as hosts, and this behavior will continue. Computer worms use recursive methods to copy themselves without host programs and distribute themselves based on exploiting the advantages of exponential growth, thus controlling and infecting more and more computers in a short time. Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.

Many worms are designed only to spread, and do not attempt to change the systems they pass through. However, as the Morris worm and Mydoom showed, even these "payload-free" worms can cause major disruption by increasing network traffic and other unintended effects.

Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ADSL differs from the less common symmetric digital subscriber line (SDSL). In ADSL, bandwidth and bit rate are said to be asymmetric, meaning greater toward the customer premises (downstream) than the reverse (upstream). Providers usually market ADSL as an Internet access service primarily for downloading content from the Internet, but not for serving content accessed by others.

A symmetric digital subscriber line (SDSL) is a digital subscriber line (DSL) that transmits digital data over the copper wires of the telephone network, where the bandwidth in the downstream direction, from the network to the subscriber, is identical to the bandwidth in the upstream direction, from the subscriber to the network. This symmetric bandwidth can be considered to be the opposite of the asymmetric bandwidth offered by asymmetric digital subscriber line (ADSL) technologies, where the upstream bandwidth is lower than the downstream bandwidth. SDSL is generally marketed at business customers, while ADSL is marketed at private as well as business customers.

More specifically, SDSL can be understood as:

Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel in a communication network, such as Ethernet or packet radio. The data that these messages contain may be delivered over physical or logical links, or through network nodes. Throughput is usually measured in bits per second (bit/s, sometimes abbreviated bps), and sometimes in packets per second (p/s or pps) or data packets per time slot.

The aggregate throughput is the sum of the data rates that are delivered over all channels in a network. Throughput represents digital bandwidth consumption.