kafka消息确认ack_什么是确认（ACK）？ ACK代表什么？

kafka消息确认ack

ACK：致谢 (ACK: Acknowledgment)

An acknowledgment (ACK) is a signal that is passed among the communicating processes, computers, or devices to indicate acknowledgment, or delivery of the message, as a component of a communications protocol in the process of data networking, telecommunications, and computer buses. The acknowledgment signal, which is sent to discard a formerly acknowledged or received message or to specify some type of error, is known as negative-acknowledgment (NAK or NACK). Acknowledgments and negative acknowledgments put in the picture of a sender of the receiver's condition or situation so that it can regulate its condition according to the situation.

确认(ACK)是在通信过程，计算机或设备之间传递的信号，用于指示消息的确认或传递，作为数据网络，电信和计算机总线过程中的通信协议的组成部分。发送以丢弃先前已确认或已接收的消息或指定某种错误类型的确认信号称为否定确认(NAK或NACK) 。在发送方的接收者的状况或情况的图片中放入了确认和否定确认，以便接收方可以根据情况调整其状况。

A lot of times, data messages in telecommunications comprise checksums to authenticate the truthfulness and reliability of the payload and header.
很多时候，电信中的数据消息包含校验和以验证有效载荷和报头的真实性和可靠性。
Checksums operate in such a manner that if a single bit of the data is degraded; the checksum would have a different value, hence they can make available a reasonably priced manner to make sure for possible signal truthfulness and reliability.
校验和的操作方式是：如果数据的单个位被降级，则校验和以此类推。校验和将具有不同的值，因此它们可以提供合理定价的方式以确保可能的信号真实性和可靠性。
If a message is acknowledged with an unacceptable checksum (that is, the data acknowledged would have a different checksum than the message had), the receiver can be acquainted with that some information was degraded or ruined.
如果以不可接受的校验和确认消息(即，所确认的数据将具有与消息不同的校验和)，则接收者可能会了解某些信息已降级或损毁。
The majority time and again, when checksums are made use of, a degraded or ruined message acknowledged will either not be served an ACK signal, or will be served a NAK signal.
在大多数情况下，一次使用校验和时，将不会向已确认的降级或破坏消息提供ACK信号，也不会提供NAK信号。

协议的使用 (Use of Protocols)

A variety of protocols are acknowledgment-based, which signifies that they positively acknowledge receipt of messages.
各种协议都是基于确认的，这表示它们肯定地确认了消息的接收。
The internet's Transmission Control Protocol (TCP) is an example of an acknowledgment-based protocol. When computers communicate through TCP, received packets are acknowledged by sending back a packet with an ACK bit set.
互联网的传输控制协议(TCP)是基于确认的协议的示例。当计算机通过TCP进行通信时，通过将设置了ACK位的数据包发回来确认收到的数据包。
The TCP protocol enables these acknowledgments to be comprised of data that is sent in a contradictory direction.
TCP协议使这些确认能够包含以相反方向发送的数据。
A variety of protocols send a particular acknowledgment per packet of information.
各种协议会在每个信息包中发送特定的确认。

Additional protocols such as TCP and ZMODEM enable a lot of packets to be transmitted before receiving acknowledgment for any of them, a course of action is essential to pack or load high bandwidth-delay product links with a huge number of bytes in flight.
诸如TCP和ZMODEM之类的附加协议可以在接收到任何数据包的确认之前先传输大量数据包，因此，采取行动是打包或加载具有大量运行中字节数的高带宽延迟产品链路的关键。
Further protocols are NAK-based, which signifies that they only act in response to messages if there is a problem. Examples consist of the majority of trustworthy multicast protocols which send a NAK when the receiver identifies absent or mislaid packets.
其他协议基于NAK，这表示它们仅在出现问题时才响应消息。示例包括大多数可信赖的多播协议，当接收方识别出缺少或错误放置的数据包时，这些协议会发送NAK。
Still, other protocols put together the use of both NAKs and ACKs.
还有，其他协议将NAK和ACK的使用放在一起。
Examples of these protocols are Binary Synchronous Communications (Bisync) and Adaptive Link Rate (for Energy-Efficient Ethernet).
这些协议的示例是二进制同步通信(Bisync)和自适应链路速率(用于节能以太网)。