Handshaking
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Categories: Articles to be expanded since January 2008 | All articles to be expanded | Articles lacking sources from October 2007 | All articles lacking sources | Data transmission | Network architecture | Network protocols
This article is about the computer science term. For the greeting habit, see handshake. For the mathematical lemma, see Handshaking Lemma.
In information technology, telecommunications, and related fields, handshaking is an automated process of negotiation that dynamically sets parameters of a communications channel established between two entities before normal communication over the channel begins. It follows the physical establishment of the channel and precedes normal information transfer. When a computer communicates with another device like a modem or a printer it needs to handshake with it to establish a connection Handshaking may be used to negotiate parameters that are acceptable to equipment and systems at both ends of the communication channel, including, but not limited to, information transfer rate, coding alphabet, parity, interrupt procedure, and other protocol or hardware features. Handshaking makes it possible to connect relatively heterogeneous systems or equipment over a communication channel without the need for human intervention to set parameters. One classic example of handshaking is that of modems, which typically negotiate communication parameters for a brief period when a connection is first established, and thereafter use those parameters to provide optimal information transfer over the channel as a function of its quality and capacity. The "squealing" (which is actually a sound that changes in pitch 100 times every second) noises made by some modems with speaker output immediately after a connection is established are in fact the sounds of modems at both ends engaging in a handshaking procedure; once the procedure is completed, the speaker might be silenced, depending on the driver. Modem handshakes can often be muted by going to the control panel and selecting the appropriate options. It is a process that takes place when a computer is about to communicate with a device to establish rules for the communication.de:Datenflusskontrolle it:Handshake pl:Handshake pt:Handshake |
