Answer to Question #272271 in Computer Networks for may

Question

Discuss Connection establishment and connection release in transmission protocol with diagrammatic illustrations.

Answer 1

Connection establishment

TCP hosts must establish a connection-oriented session with one another in order for transport services to be reliable. The three-way handshake procedure is used to establish the connection. By allowing both ends of a network to agree on initial sequence numbers, a three-way handshake synchronizes both ends of the network. This approach also ensures that both parties are prepared to provide data and are aware that the other is open to communicating. This is necessary to prevent packets from being shared or retransmitted during session setup or termination. Each host chooses a sequence number at random to keep track of bytes in the stream it is transmitting and receiving.

The three-way handshake is performed as indicated in the diagram below.

The requesting end (Host A) sends an SYN segment with the server's port number and beginning sequence number for the client to connect to (x). Host B acknowledges its own SYN segment, which includes the server's beginning sequence number (y). The server additionally accepts the sender's SYN plus one (X + 1) in response to the client SYN. One sequence number is consumed by an SYN. Accepting the server's SEQ plus one (SEQ = x + 1, ACK = y + 1), the client should acknowledge this SYN from the server. A TCP connection is established in this manner.

Connection Release

While three segments are required to establish a connection, four segments are required to terminate one. Each way of a TCP connection should be shut down individually when it is full-duplex (that is, data flows in each direction independently of the other direction). The graphic depicts the termination method for each host. When one end has done sending data, the other end might exchange a FIN.

When a TCP receives a FIN, it should inform the application that the other end of the data flow direction has been ended. The application issuing a closure generally results in the transmission of a FIN. The receipt of a FIN just indicates that data will no longer flow in that direction. After getting a FIN, a TCP can transfer data. The active closure is executed by the end that sends the first FIN (for example, transmit the first FIN).