Physical layer: bits, signals, and transmission media

The physical layer, bits, signals, and transmission media are the core concepts of this lesson, which focuses on the lowest level of the network stack and data transmission via a physical medium.
The text explains that at the physical layer, data is no longer treated as packets or frames, but rather as sequences of 0s and 1s to be converted into transmissible signals.

The lesson outlines the main transmission media: electrical (such as copper cables), optical (such as fiber optics), and wireless (based on electromagnetic waves). It also explains the difference between analog and digital signals, using NRZ encoding as an example.

The final section examines fiber optics in greater detail, describing its structure—core, cladding, coating, strength member, and outer jacket—and the principle of total internal reflection, which allows light to remain guided within the fiber’s core, even over long distances.

Bibliography

Primary sources

IEEE. IEEE 802.3 — Ethernet Working Group Standards. IEEE Standards Association.

IEEE. IEEE 802.11 — Wireless LAN Medium Access Control and Physical Layer Specifications. IEEE Standards Association.

ISO/IEC. ISO/IEC 11801-1:2017 — Information technology — Generic cabling for customer premises — Part 1: General requirements.

ANSI/TIA. ANSI/TIA-568 — Commercial Building Telecommunications Cabling Standard.

ITU-T. Recommendation G.652 — Characteristics of a single-mode optical fibre and cable.

ITU-T. Recommendation G.651.1 — Characteristics of a 50/125 µm multimode graded index optical fibre cable.

IEC. IEC 60793 — Optical fibres.

IEC. IEC 60794 — Optical fibre cables.

ITU. Radio Regulations.

ITU-T. Recommendation G.703 — Physical/electrical characteristics of hierarchical digital interfaces.

ISO/IEC. ISO/IEC 7498-1 — Open Systems Interconnection — Basic Reference Model: The Basic Model.

Secondary sources

Kurose, J. F., & Ross, K. W. Computer Networking: A Top-Down Approach. Pearson.

Stallings, W. Data and Computer Communications. Pearson.

Forouzan, B. A. Data Communications and Networking. McGraw-Hill.

Comer, D. E. Computer Networks and Internets. Pearson.

Peterson, L. L., & Davie, B. S. Computer Networks: A Systems Approach. Morgan Kaufmann.

Rappaport, T. S. Wireless Communications: Principles and Practice. Pearson.

Hecht, J. Understanding Fiber Optics. Pearson / Laser Light Press.

Index

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