What is the purpose of the acknowledgement field in the TCP header?

Which TCP code bits are involved in a TCP three-way handshake?

TCP Header 20bytes IP Header Length TCP Header Source Port Resv. S WCRC Sequence Number Acknowledge Number REGKHTNN Checksum Options Data Destination Port Window Urgent Pointer Padding 31 The TCP header allows TCP based applications to establish connection-oriented data streams that are delivered reliability, and to which flow control is applied. A source port number is generated where a host intends to establish a connection with a TCP based application, for which the destination port will relate to a well-known/registered port towhich a well-known/registered application is associated.