NAK (protocol message)
Encyclopedia
The NAK protocol message is sent in many communications protocols
to negatively acknowledge or reject a previously received message, or to indicate some kind of error.
Many protocols are ACK-based, meaning that they positively acknowledge receipt of messages. TCP
is an example of an ACK-based protocol.
Other protocols are NAK-based, meaning that they only respond to messages if there is a problem. Examples include most reliable multicast
protocols which send a NAK when the receiver detects missing packets.
Still other protocols make use of both NAKs and ACKs. Bisync
and Adaptive Link Rate (for Energy Efficient Ethernet) is an example.
A special case of the NAK protocol message is the negative-acknowledge character
.
Communications protocol
A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...
to negatively acknowledge or reject a previously received message, or to indicate some kind of error.
Many protocols are ACK-based, meaning that they positively acknowledge receipt of messages. TCP
Transmission Control Protocol
The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...
is an example of an ACK-based protocol.
Other protocols are NAK-based, meaning that they only respond to messages if there is a problem. Examples include most reliable multicast
Reliable multicast
A reliable multicast protocol is a computer networking protocol that provides a reliable sequence of packets to multiple recipients simultaneously, making it suitable for applications like multi-receiver file transfer or streaming media.-Overview:...
protocols which send a NAK when the receiver detects missing packets.
Still other protocols make use of both NAKs and ACKs. Bisync
Binary Synchronous Communications
Binary Synchronous Communication is an IBM link protocol, announced in 1967 after the introduction of System/360. It replaced the synchronous-transmit-receive protocol used with second generation computers. The intent was that common link management rules could be used with three different...
and Adaptive Link Rate (for Energy Efficient Ethernet) is an example.
A special case of the NAK protocol message is the negative-acknowledge character
Negative-acknowledge character
* In telecommunications, a negative-acknowledge character is a transmission control character sent by a station as a negative response to the station with which the connection has been set up....
.