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.