A frame check sequence (FCS) refers to the extra checksum characters added to a Frame in a communication protocol for error detection and correction. A checksum is a form of redundancy check, a very simple measure for protecting the integrity of data by detecting errors in data that is sent through space (telecommunications) or time (storage). ... In telecommunications, a frame is a packet which has been encoded for transmission over a particular link. ... This article concerns communication between pairs of electronic devices. ...
The sending host computes a checksum on the entire frame and sends this along. The receiving host computes the checksum on the frame using the same algorithm, and compares it to the received FCS. This way it can detect whether any data was lost or altered in transit. It may then discard the data, and request retransmission of the faulty frame. A cyclic redundancy check is often used to compute the FCS. A cyclic redundancy check (CRC) is a type of hash function used to produce a checksum - which is a small number of bits - against a byte or a larger block of data, such as a packet of network traffic or a block of a computer file. ...
An ethernet frame, including the FCS terminating the frame.
FCS is used in ethernet, X.25, HDLC, Frame Relay, and other data link layer protocols. Image File history File links Diagram of an ethernet frame. ... Ethernet is a frame-based computer networking technology for local area networks (LANs). ... X.25 is an ITU-T standard protocol suite for WAN networks using the phone or ISDN system as the networking hardware. ... High-Level Data Link Control (HDLC) is a bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization (ISO). ... Frame relay, also found written as frame-relay, is an efficient data transmission technique used to send digital information quickly and cheaply to one or many destinations from one or many end-points. ... In telecommunication, the term data link has the following meanings: The means of connecting one location to another for the purpose of transmitting and receiving data. ... This article concerns communication between pairs of electronic devices. ...
External links
Serversniff.net Online-Tool to compute FCS-Vals from strings
See also
Jacksum Software implementing various message verification functions, including FCS-16.
A framechecksequence generator of essentially the same configuration as the tester provides a word based on the content of the data which is altered if the parity is incorrect.
Framechecksequence generator tester 44 provides, with a degree of certainty dependent on the selected polynomial, a logic output indicating whether the data received from generator 42 is correct or contains an error.
To produce an incorrect framechecksequence in the transmitter in response to a parity error, as determined by parity tester 64, line 157 to the D input of flip-flop 158 is broken at point "X" and an EXCLUSIVE OR gate 183 associated with parity tester 64 (FIG.
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