Module 4

Study Notes

A socket represents one endpoint of a two-way communication link between two programs on a network, associated with a specific port number.
Each endpoint consists of an IP address and a port number.
In every TCP connection, two endpoints are identified, enabling multiple connections between hosts and servers.

Connection-oriented sockets establish a direct link between two socket endpoints, utilizing the Transmission Control Protocol (TCP) to ensure reliable data delivery.
Connectionless sockets operate without the need for an explicit connection setup before data transmission, using the User Datagram Protocol (UDP) for faster data delivery.

For a connection request, the client needs the server machine's IP address and port number.
The server initiates a socket, binds it to a local port number, and then awaits connections.
Once a connection is established, communication between client and server occurs through socket read and write operations.

In UDP, there is no connection setup between client and server, and no initial handshaking is required before communication.
Clients explicitly specify the server's IP address and port number, and servers extract the client's IP address and port number.
Data transmitted between client and server via UDP can be lost or arrive out of order.

For communication to begin, the client initiates contact with the server, which must be operational and prepared to receive connections.
The client creates a socket, providing the server's IP address and port number.
During the TCP handshake, the server generates a new socket specifically for communicating with that client.
A new socket is created for each TCP client that contacts the server, and this new socket is dedicated to communication with that client throughout the entire TCP connection.
The TCP connection offers reliable and sequential byte-stream transmission between the client and server processes.