Network Software and Layered Concepts

Why Layering in Networks?

• Networking is complex (software, firmware, hardware, signals).
• To simplify → networking is divided into layers, where each layer performs a specific function.
• Layers are independent but work together by exchanging input/output.

Layered Tasks

• A networking process is broken into smaller tasks.
• Each layer handles only its task and communicates with its peer layer on the other machine.
• Data is passed downward (from application to physical) at sender and upward at receiver.
• Each layer uses encapsulation (adding headers/trailers) to identify its peer.

Protocols

• Definition: Set of rules that govern communication between devices.
• Protocols define:
  • Syntax → Structure/format of data (bit order, fields).
  • Semantics → Meaning of bits (e.g., address = sender/receiver).
  • Timing → When & how fast data should be sent.
• Examples: TCP, UDP, HTTP, IP, FTP, etc.

Layering Concepts and Benefits

• Network architecture = Set of layers + protocols.
• Each layer offers services to the one above.