In this article we will discuss TCP Three-way Handshake Analysis, will make brief discussion on TCP Three-way Handshake Analysis, In last article we discuss about TCP Connection Establishment.
Hosts track each data segment within a session and exchange information about what data is received using the information in the TCP header. TCP is a full-duplex protocol, where each connection represents two one-way communication streams or sessions. A three–way handshake is a method used in a TCP/IP network to create a connection between a local host/client and server. It is a three-step method that requires both the client and server to exchange SYN and ACK (acknowledgment) packets before actual data communication begins.
To establish the connection, the hosts perform a three-way handshake. Control bits in the TCP header indicate the progress and status of the connection.
The three-way handshake:
Establishes that the destination device is present on the network
Verifies that the destination device has an active service and is accepting requests on the destination port number that the initiating client intends to use
Informs the destination device that the source client intends to establish a communication session on that port number
After the communication is completed, the sessions are closed, and the connection is terminated. The connection and session mechanisms enable TCP’s reliability function.
The six bits in the Control Bits field of the TCP segment header are also known as flags. A flag is a bit that is either set to on or off. Click the Control Bits field in the figure to see all six flags. We have discussed SYN, ACK, and FIN. The RST flag is used to reset a connection when an error or timeout occurs.