Chapter 2 Part 1: Network Application Fundamentals

• Application Layer

The top layer of the Internet protocol stack where network applications and their protocols operate, enabling communication between software on different devices.

• Network Applications

Programs like email, web browsers, and streaming services that rely on network connectivity to function and exchange data.

• Client-Server Architecture

A model where a server provides services and resources to multiple clients, which initiate communication but do not interact directly with each other.

• Peer-to-Peer (P2P) Architecture

A decentralized model where devices (peers) communicate directly, sharing resources and services without a central server.

• Process

A running instance of a program on a host; processes on different hosts communicate by sending messages across the network.

• Socket

An interface between a process and the transport layer, acting like a door through which messages are sent and received.

• IP Address

A unique identifier assigned to a device on a network, used to route messages to the correct host.

• Port Number

A numerical identifier used alongside an IP address to specify a particular process or service on a host (e.g., port 80 for HTTP).

• App-layer Protocol

A set of rules defining how applications communicate over a network, including message formats, types, and exchange procedures.

• Transport Layer

Responsible for delivering messages between processes, providing services like reliability, flow control, and congestion management.

• TCP (Transmission Control Protocol)

A connection-oriented protocol that ensures reliable, ordered, and error-checked delivery of data between applications.

• UDP (User Datagram Protocol)

A connectionless protocol that offers fast but unreliable data transmission, suitable for time-sensitive applications like streaming.

• SSL (Secure Sockets Layer)

A security protocol that provides encrypted communication, data integrity, and authentication over TCP connections.

• RFC (Request for Comments)

A formal document from the Internet Engineering Task Force (IETF) that defines standards and protocols for the Internet.