Editing Longitudinal redundancy check (section)

{{Short description|Error detection number calculated over a serial data stream}}
In telecommunication, a '''longitudinal redundancy check''' (LRC), or '''horizontal redundancy check''', is a form of [[redundancy check]] that is applied independently to each of a parallel group of bit streams.  The data must be divided into [[transmission block]]s, to which the additional check data is added.

The term usually applies to a single [[parity bit]] per bit stream, calculated independently of all the other bit streams ([[BIP-8]]).<ref name="rfc935">
{{IETF RFC|935}}: "Reliable link layer protocols".
</ref><ref>
[http://www.slideshare.net/angelgdiaz_ut/errors-error-detection-and-error-control-8600677 "Errors, Error Detection, and Error Control:  Data Communications and ComputerNetworks: A Business User's Approach"].</ref>

This "extra" LRC word at the end of a block of data is very similar to [[checksum]] and [[cyclic redundancy check]] (CRC).