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22-Elec-B4 Information Technology Networks: May 2018

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Cellular Telephony — OFDM Orthogonality, PRB Peak Rate and FDMA Capacity
  2. Question 2 Transport Layer Protocols — TCP, UDP and Congestion Control
  3. Question 3 Shortest-Path Routing — Dijkstra's Algorithm
  4. Question 4 WiFi and Bluetooth — Piconets, Frequency Hopping and Medium Access
  5. Question 5 Layered Architecture — The OSI Reference Model

Start with Question 1 →

Paper format. Professional Engineers of Ontario — National Examinations, May 2018, 16-Elec-B4 Information Technology Networks. Three hours, closed book; one Casio or Sharp approved calculator permitted. The paper prints five questions of 25 marks each and any four constitute a complete paper worth 100 marks, with the marks for every sub-part shown in the left margin. All five questions are solved here, because this set is a study resource rather than an exam attempt, and because a candidate choosing which four to answer benefits from seeing the fifth worked out.

Reference texts. A. Leon-Garcia and I. Widjaja, Communication Networks: Fundamental Concepts and Key Architectures, 2nd ed. (the syllabus reference for this code); J. F. Kurose and K. W. Ross, Computer Networking: A Top-Down Approach, 8th ed.; A. S. Tanenbaum and D. J. Wetherall, Computer Networks, 5th ed.; W. Stallings, Wireless Communications and Networks, 2nd ed.; T. S. Rappaport, Wireless Communications: Principles and Practice, 2nd ed.; S. Sesia, I. Toufik and M. Baker, LTE — The UMTS Long Term Evolution, 2nd ed.

Source reading — Question 3 figure. The printed network labels two different nodes with the letter F: one on the upper row between D and the right-hand vertex, and one at the far right. This is a typographical slip in the examination paper. To keep the working unambiguous the far-right node is written F′ throughout; every distance and path below is unaffected by the naming, and a candidate should simply state the convention adopted, exactly as the paper's own instruction on assumptions invites.

Source reading — Question 2(d). The printed text says “Repeat part b”, but part (b) is the qualitative question about congestion in wired networks and carries no window to repeat. The intended reference is part (c), whose window evolution is the thing a lost packet perturbs. Part (d) is answered on that reading, and the reading is stated in the answer rather than assumed silently.