i) Rec. X.200: A function which controls the flow of data within a layer or between adjacent layers of a Protocol ,or between peer entities. ii) Series X*: In data communication, control of the data transfer rate. iii) (signalling) traffic Flow Control :Actions and procedures intended to limit signalling traffic at its source in the case where the signalling network is not capable of transferring all signalling traffic offered by the User Parts , because of network failures or overload situations. Furthermore, within the EU-P308 the term Flow Control may also be used for iv) load control algorithms restricting the acceptance of Call attempts, source: ITU-T Q.9, X.200,VI Fascicle I.3 domain: General usage: EU-P308

The way in which information is controlled in a network to prevent loss of data when the receiving buffer is near its capacity.

The procedure for controlling the rate of transfer of packets between two designated points in a data network; used to prevent data loss during transmission.

A method used in networking for congestion avoidance and traffic regulation.

A specific production control system based primarily on determining production rates and feeding material into production to meet the planned rates, then monitoring it through production to verify that it is moving at the desired speed. Flow control has its major application in repetitive production.

A congestion control mechanism. Congestion is caused by devices sending traffic to already overloaded port on a Switch. Flow control prevents packet loss and inhibits devices from generating more traffic until the period of congestion ends.

This is a method of controlling the transfer of information (messages, characters, etc.) between a network's data points.

Method by which the transmission of data may be stopped and started by the receiver, for example to prevent buffer overflow.

A communications term that refers to the control the flow of data over a communications link. Flow control is one of the network-processing functions defined in the transport layer (Layer 4) of the Open Systems Interconnection (OSI) model (see OSI).

Signalling between computers where pauses in data transmission pace the data received.

A technique used for data transmission that lets your computer rate (i.e. the transfer rate between the computer and a modem) be different from the connection rate (i.e. the line speed). Flow control is useful with data compression because if the throughput is higher than the connection rate, the throughput will vary depending on the compressibility of the data. It lets your modem and computer tell each other when they're ready to accept more data for transmission and when to wait. This "handshaking" prevents data from being lost because the computer or modem was busy, and comes in two forms, hardware mode (known as RTS/CTS), and software mode (known as XON/XOFF) flow control.

Measures designed to adjust the flow of traffic into a given airspace, along a given route, or bound for a given aerodrome, so as to ensure the most effective utilization of the airspace. Fr: régulation du débit

Flow control is used to manage the sending of traffic so the sending device does not transmit more than the receiving device can process. This helps prevent traffic from being dropped and having to be resent. See also IEEE802.3 Flow Control and Back Pressure Flow Control.

A means of regulating the rate at which data transfer takes place between devices to protect against data overruns.

Enables lower speed devices to communicate with higher speed devices, that is, that the higher speed device refrains from sending packets.

A precision adjustable valve used to control the flow of a gaseous or liquid media.

Any of several methods that are used to control the flow of information from one device to another, by causing the sending device to wait temporarily until the receiving device is ready. Also see handshaking

A method of controlling when information is sent. Can be controlled by either software (XON/XOFF) or hardware (CTS/RTS).

This modem feature often reserves certain control characters (i.e., CTRL+c, CTRL+s, etc.) that lets the communications software manage the flow of data between your computer and the remote computer. These control characters are also used by many programs, such as the Emacs editor. If your modem has XON/XOFF turned on, it will intercept these control characters and prevent them from being sent to the file you are trying to edit.

Regulation of traffic allowed into specific portions of a network to avoid excessive congestion. Flow Control is performed by a receiving entity to limit the amount or rate of data sent by a transmitting entity.

Method of controlling the transmission of data to ensure that all the transmitted data is received; allows the receiving device to request the transmitting device to pause and then resume the data flow. Hardware (RTS/CTS) flow control depends on two RS232 pins to signal the pause and resumption of data flow. Software (Xon/Xoff) flow control uses software control characters to signal the pause and resumption of data flow.

Flow control is the management of data flow between computers or devices or between nodes in a network so that the data can be handled at an efficient pace. Too much data arriving before a device can handle it causes data overflow, meaning the data is either lost or must be retransmitted.

A device which meters the rate of fluid.

(n.) A STREAMS mechanism that regulates the rate of message transfer within a Stream and from user space into a Stream.

A method for a receiver to control the information flow from a transmitter. It eliminates data overflow at the receiver.

When processing capability between 2 devices are dramatically different, say dot matrix serial printer and RS-232, Flow Control is necessary to regulate data flow to ensure the communicate. There are basically 2 approaches to do flow control for RS-232 communication. Software approach : XON/XOFF XON(0x11) and XOFF(0x13) are defined as special control code during communication. These 2 codes will be transmitted together with data characters. When either of the devices receives XOFF, it stops transmitting data until XON receives. The deficiency for this approach is that the data must not contain these 2 codes. Hardware approach: RTS/CTS RTS(Request To Send) and CTS(Clear To Send) are 2 signals for hardware flow control. RTS is an output signal that enables/disables data transmission for the other device. CTS is an input signal allowing the other device to enable/disable data transmission. The deficiency for this approach is that it needs 2 more wires but provide the capability to send binary data.

The procedures for controlling the rate of transfer of data between two points in a data network, such as between a protocol converter and a printer. This avoids data loss when a recipient device's buffer is full. Buffers play an essential role in overall flow control in a network.

A method of controlling the rate at which one device sends data to another. Two types of flow control are Hardware (RTS/CTS) and Software (XON/XOFF). Hardware Flow Control (RTS/CTS): Hardware flow control (Request to Send/Clear to Send) is the most effective method. It uses special wires in the cable to control the flow of data. It is used between two devices that are immediately connected, such as a computer and a modem. Software Flow Control (XON/XOFF): Software flow control is less effective and more prone to data corruption, delays, and loss of data. Software flow control should be used only if hardware flow control is unavailable.

In PIO transfers, the ability of an EIDE drive to control the speed at which the host transfers data to or from the drive by using the IORDY signal. The host temporarily stops transferring data whenever the drive deasserts the IORDY signal. When the drive reasserts the IORDY signal, the host continues the data transfer.

A term often used to describe a specific production control system.

The process of controlling data transmission at the sender to avoid overfilling buffers and loss of data at the receiver.

The mechanism that regulates the flow of data between two devices. Modems typically have two methods of flow control software flow control (XON/XOFF) and hardware flow control (CTS/RTS).

Compensates for the difference between the rate at which data reaches a device and the rate at which the device processes and transmits. The two common types of flow control are RTS/CTS signaling (a hardware based method, employing an electrical signal) and XON/XOFF (a software-based method using standard ASCII control characters to pause or resume transmission). The \G command controls XON/XOFF flow control.

A function in a protocol used to control the flow of signalling messages between adjacent layers of a protocol, and/or between peer entities. The function permits, for example, a receiving entity to control signalling message flow from the sending entity.

As it's name implies, flow control is a method for controlling when a device sends (or doesn't send) data. Flow control can be done with hardware or software. In software flow control schemes, a particular character (the Xoff, or Transmit off character) is sent to the transmitting device to tell it that it the the receiver is unable to accept any more data. The sender will then wait until it receives the Xon character before sending any more data.

Programming expressions that direct the execution of a procedure. If, Then, Else, End If is a flow control statement.

In SNA, the process of managing the rate at which data traffic passes between components of the network. The purpose of flow control is to optimize the rate of flow of message units with minimum congestion in the network; that is, to neither overflow the buffers at the receiver or at intermediate routing nodes, nor leave the receiver waiting for more message units.

A method of controlling when information is sent. One method is Xon/Xoff, where a BBS will send information until your computer sends an Xoff (CTRL-S). It will resume sending information when you send an Xon.

The target indicates to the initiator when the last packet of a data stream will be transferred so that the initiator can flush FIFOs and terminate pre-fetch sooner than previously possible. Basically, the target is warning the initiator that the transfer is almost complete so that it can prepare for the next transfer while the target completes the current transfer.

(1) The function of a receiving entity to limit the amount or rate of data that is sent by a transmitting entity. (2) The control of the rate at which hosts or gateways inject packets into a network or Internet, usually to avoid congestion. Flow control mechanisms can be implemented at various levels and allow communicating layers to match their data transfer and receive rates. Simplistic schemes, like ICMP source quench, simply ask the sender to cease transmission until congestion ends. More complex schemes vary the transmission rate continuously.

A mechanism that compensates for differences in the flow of data input to and output from a modem or other device. Necessary to keep a modem from sending data faster than a computer can handle it, to prevent overflow and data loss.

A method of controlling the amount of data that two devices exchange. In data communications, flow control prevents one modem from "flooding" the other with data. If data comes in faster than it can be processed, the receiving side stores the data in a buffer. When the buffer is nearly full, the receiving side signals the sending side to stop until the buffer has space again. Between hardware (such as your modem and your computer), hardware flow control is used; between modems, software flow control is used.

Comprised of the hardware, software and procedure for controlling the transfer of IP packets between two points on a network.

Also called handshake. The processes used to regulate the rate at which information is transferred from one device to another. One device sends a signal to the other when information can be transferred.

Technique for ensuring that a transmitting entity, such as a modem, does not overwhelm a receiving entity with data. When the buffers on the receiving device are full, a message is sent to the sending device to suspend the transmission until the data in the buffers has been processed. In IBM networks, this technique is called pacing.

A mechanism that compensates for differences in the flow of data into and out of a modem or other device. See commands &Hn, &In, &Rn.

An air metering device used to control the speed of an air cylinder. Usually metering the air in one direction only, allowing full flow in the opposite direction.

A mechanism that starts and stops the flow of data to compensate for differences in the flow of data into and out of a modem or other device.

A device that controls flow independent of pressure drop. Back to glossary index.

Water discharge assembly consisting of a screen/washer and a three-holed orifice which control the water flow rate.

The procedure for regulating the flow of data between two devices; prevents the loss of data once a device's buffer has reached its capacity.

A method for controlling the flow of data between the reader and the serial port. It stops the transmitting device from sending data when the receiving device buffer fills up and starts it again when the buffer empties. This can be done through software (XON/XOFF) or hardware (CTS/RTS).

A system that uses buffering and other mechanisms, such as controls that turn a device on and off, to prevent data loss during transmission.

The management of transmission between two devices such as nodes in a network or between the CPU and peripheral devices. It provides notification to the sending device to slow down or speed up data transmission or data transfer due to the receiving device's current ability to keep up with it. Flow control also enables slower-speed devices to communicate with higher-speed ones and vice versa. For example, in the Teligent SMS Broadcast Server system or Content Provider solution, the flow control parameter limits the influx of messages to the SMSC or MMSC. This ensures that the SMSC or MMSC will not be overloaded with 3rd party messages, which then ensures that person-to-person messages are always delivered within the required response time.

In X.25 communications, the procedure for controlling the data transfer rate.

The management of the flow of data between Data Provider and Service Provider in order to assure that neither end of the transaction suffers overload. Flow control is generally realized in the OAI-PMH through the use of resumption tokens.

A mechanism that compensates for differences in the flow of data to and output from a modem or computer. Either hardware or software can be used for this control to prevent data loss. Hardware flow control using the modem makes use of a buffer to store data to be sent and data received. Flow control is necessary if the Communications port is locked at a higher rate than the connection rate. This is especially important for high speed modems, like 14,400 bps and above, that should almost always be setup for CTS/RTS hardware flow control.

In computer networking, flow control is the process of managing the rate of data transmission between two nodes. This should be distinguished from congestion control, which is used for controlling the flow of data when congestion has actually occurred . Flow control mechanisms can be classified by whether or not the receiving node sends feedback to the sending node.