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Department of Computer Science and Technology

Computer Networking


Course pages 2023–24

Computer Networking



The current (As at 28-feb-2024) model answer for y2020 p4 q5 (spanning tree with disruption) is not correct. The question is sound, but the answer in the repo is incorrect and will be updated. (Thank you, and apologies, to those who were seeking clarification.) - specifically the model answer builds an incorrect forwarding table and thus the disruption impact is changed.


The first half of the recording has no audio. (oops.) This Topic01 lecture is taken from 2022 but I believe fullfils the need.


Version 2024.1 of the slides and Handout 1 are now available.


  • Topic 1 Introduction / Foundation pptx pdf Updated: 2024-01-08

  • Topic 2 Architecture and Internet pptx pdf Updated: 2024-01-08

  • Topic 3 Physical and Data-Link Layer pptx pdf Updated: 2024-01-08

  • Topic 4 Network Layer pptx pdf Updated: 2024-01-08

  • Topic 5 Transport Layer pptx pdf pdated: 2024-01-08

  • Topic 6 Network Applications pptx pdf Updated: 2024-01-08

Slides as 6up pdf Handouts

  • Topic 1 to Topic 6 pdf Updated: 2024-01-08


There are many textbooks; I rather like these:

Alongside these is this favorite, the textbook URL below also links to many demo applets

  • Computer Networking: A Top-Down Approach

    Jim Kurose and Keith Ross

    Currently in its 8th edition, Jim and Ross work hard to keep it up to date and while college libraries may contain older versions the texts contain considerble, timeless, material.

    As part of Wired's "Experts explain" series Jim did this excellent one about the Internet available on YouTube

Supervision Handouts

  • Supervison Questions PDF

  • Topic-specific material

    Topic 1 - Foundation (Introduction)

    • How long is a nanosecond? Grace Hooper on YouTube
    • Grace Hopper on Letterman via dailymotion
    • As mentioned in lecture 2 - Gibbens,Kelly/Key Dynamic Alternative Routing Frank's page here
    • Travelling waves on the motorway here, here and here
    • Hark Handley's early Satellite videos speculating on SpaceX's deployment YouTube

    Topic 2 - Foundations and Architecture

    • End-to-End Arguments in System Design, Saltzer, J., Reed, D., and Clark, D.D., Second International Conference on Distributed Computing Systems (April 1981) pages 509-512, ACM Transactions on Computer Systems, 1984, Vol. 2, No. 4, November, pp. 277-288 PDF
    • Andrew D. Birrell and Bruce Jay Nelson, "Implementing remote procedure calls", ACM Transactions on Computer Systems 2(1), 1984, (ACM PDF)
    • David Tennenhouse, "Layered Multiplexing Considered Harmful", Protocols for High-Speed Networks, Rudin and Williamson (Editors), NorthHolland, Amsterdam, 1989 (Citeseerx PDF)
    • An xkcd OSI joke cartoon Modern OSI Model

    Topic 3 - Data-Link (Media Access) and Physical

    • R Metcalfe and D Boggs, "Ethernet: Distributed Packet Switching for Local Computer Networks", ACM Computer Systems, 1976. (PDF)
    • Hedey Lamarr (co-inventor of Code-Division Multiple Access) Google doodle here
    • Dealers of Lightning: Xerox PARC and the Dawn of the Computer Age - book mentioned 2020-2-5 here

    Topic 4 - Networks (warning some silliness)

    • A detailed discussion of how BGP mistakes lead to YouTube hijacking Hijacking the Internet
    • IPv4 address space is virtually exhausted..... news at 11; lecture material around Topic 4. This web page points to many of the "the Internet is about to end.... Doom I tell you....." gadgets and pages on the Internet.
    • The Day The Routers Died... from RIPE 55 network operators meetings in 2007.
    • Internet Kill Switch
    • IPv6 is still broken, or missing, in most vendors' consumer network gear old article - 2011
    • A Few of my favorite things Delightful video by the people at CAIDA while fabulously dated, the issues of bad decisions, bad law and the simple wonder of the Internet carry on.
    • Sally Floyd and Van Jacobson. 1993. The synchronization of periodic routing messages. In Conference proceedings on Communications architectures, protocols and applications (SIGCOMM '93). ACM, New York, NY, USA, 33-44. (PDF)
    • Vern Paxson and Sally Floyd, "Wide-Area Traffic: The Failure of Poisson Modeling", IEEE/ACM Transactions on Networking, 3(3), 1995 (PDF)
    • A comparison of different VPN security protocols here

    Topic 5 - Transport

    Questions came up about TCP flow-control, here are some links to help. The first is an excellent hands-on examination using wireshark.

    Sadly, none of these show clearly the behaviour for TCP RcvWindow when some packets are received out of order.

    Topic 6 - Applications

    • dns toys is an example of the insanity to which dns can be put
    • Varnish is a front-facing cache. Poul-Henning Kamp is it's primary author/architect, he wrote this interesting piece on VM, not specifically relevant for CompNet but certainly relevant to "Systems Thinking" people.
    • Tim Berners Lee's machine at CERN
    • DNS Measurements at a Root Server
    • Speed testing HTTP vs HTTPS
    • Baset et al., "An Analysis of the Skype Peer-to-Peer Internet Telephony Protocol", IEEE INFOCOMM 2006, PDF
    • Honda et al., "Is it Still Possible to Extend TCP?", IMC 2011, PDF
    • Sandvine Global Internet Phenomena Report for January 2023 PDF
    • Daniel Stenberg (author of curl)'s excellent graphic on curl from beginning to end Curl from start to end (Local image copy)

    Last year’s course materials are still available.