Link layer, Ethernet frames, and MAC addresses

The link layer, Ethernet frames, and MAC addresses are the core concepts of this lesson, which focuses on local communication between devices connected to the same network segment.

The text introduces the link layer—or data link layer—explaining that its function is to receive packets from the network layer and encapsulate them into frames, which are units suitable for transmission over the physical layer. The lesson then describes the roles of MAC addresses, the Ethernet protocol, and the frame structure, which consists of a header, payload, and trailer. It also examines error control mechanisms using FCS and CRC, which make it possible to verify whether a frame has arrived intact.

Finally, the lesson analyzes the journey of a web request across the network, demonstrating how the IP packet retains the sender’s and final recipient’s IP addresses, whereas the link-layer frame changes at each stage of the path between hosts, gateways, and routers.

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.

Plummer, D. C. (1982). An Ethernet Address Resolution Protocol. RFC 826. IETF / RFC Editor.

Narten, T., Nordmark, E., Simpson, W., & Soliman, H. (2007). Neighbor Discovery for IP version 6 (IPv6). RFC 4861. IETF / RFC Editor.

Postel, J. (1981). Internet Protocol. RFC 791. IETF / RFC Editor.

Deering, S., & Hinden, R. (2017). Internet Protocol, Version 6 (IPv6) Specification. RFC 8200. IETF / RFC Editor.

Baker, F. (1995). Requirements for IP Version 4 Routers. RFC 1812. IETF / RFC Editor.

Fielding, R., Nottingham, M., & Reschke, J. (2022). HTTP Semantics. RFC 9110. IETF / RFC Editor.

Eddy, W. (Ed.). (2022). Transmission Control Protocol (TCP). RFC 9293. IETF / RFC Editor.

Secondary sources

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

Tanenbaum, A. S., & Wetherall, D. J. Computer Networks. Pearson.

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

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

Stallings, W. Data and Computer Communications. Pearson.

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

Stevens, W. R. TCP/IP Illustrated, Volume 1: The Protocols. Addison-Wesley.

Index

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