negative acknowledgement


Also found in: Acronyms.

negative acknowledgement

[′neg·əd·iv ik′näl·ij·mənt]
(computer science)
In a data communications network, a control character returned from a receiving machine to a sending machine to indicate the presence of errors in the preceding block of data. Abbreviated NAK.

negative acknowledgement

(character)
(NAK) The mnemonic for ASCII character 21.

Sometimes used as the response to receipt of a corrupted packet of information.

Opposite of acknowledgement.

negative acknowledgement

(communications)
(NAK) Any message transmitted to indicate that some data has been received incorrectly, for example it may have a checksum or message length error. A NAK message allows the sender to distinguish a message which has been received in a corrupted state from one which is not received at all.

An alternative is to use only ACK messages, in which case the non-receipt of an ACK after a certain time is counted as a NAK but gives no information about the integrity of the communications channel.

See also ACK.
Mentioned in ?
Full browser ?