COMP3310/etc – Computer Networks Assignment 1 – The Last Mile
This assignment is to develop a (short) technical report that deals with a variety of network design aspects relating to building a last-mile network, with the last section making a specific design recommendation for a semi-fictitious rural setting.
You are encouraged to research widely, then interpret and present your findings. More marks will be given for deeper analysis than just repeating lecture content or slabs of internet-derived content. You will need to find more background information to answer all the questions in good depth.
- This assignment is worth 15% of the final course mark.
- It is due by 23:55 Monday 27 March, Canberra time.
- Late submissions will not be accepted, except in extenuating circumstances. o Extensions must be requested via the lecturer, and preferably well before the due date. If anything goes wrong on the due day, let the lecturer know.
- Submission will be via TurnItIn through the link on the wattle page for this course. o You can work together on the research, but your submission must be entirely your own work, with appropriate citation of any external sources. 1
For the three brief questions Q1-Q3, each answer should be around half a page long. These questions help set the scene for your analysis in Question 4 – you can reference your Q1-Q3 answers there. The response to Q4 should be around 1500 words long – can be longer, but don’t go overboard, there won’t be additional marks.
Questions: [The percentage in brackets indicates the available marks from the total] Q1: What do you think are the main benefits, and issues, of the Last Mile for Networking and Communications? [10%]
Q2: What are the main, typical, options for delivering Last Mile networks in Australia in 2023? [10%]
Q3: What are the inherent (physical) limitations on data-rates across typical Last Mile networks? [10%] The above answers are input to the following design challenge. You are strongly encouraged to include appropriate diagrams and tables, to help explain your arguments.
Q4. Develop a basic network design to meet the following needs of a rural community [70%]: Home broadband can be delivered through a range of cabled and wireless methods, each with their own costs, limitations and benefits. For this part of the assignment you need to provide a brief technical report for a rural community network organisation. Please write to a reasonable level of technical understanding, they are a well-educated community.
You should look at TurnItIn feedback to ensure you have properly referenced external materials. You can submit multiple times up to the due date. We don’t use the TurnItIn score in the mark, it gets confused/misled.
The community of the village of Bungenwood wants to build a shared network for about 600 houses, across their region, through a shared infrastructure. Ideally everyone gets the same connection technology, if not the same performance, but you can be flexible in your design if it’s justifiable. The minimum requirement is that every farm gets 50Mb/s down, though anything better is welcome.
The sketches below show the layout of the houses. There are two regions, the higher density village, a square of 36 blocks, each 2km by 2km (centre of Fig 1), with each block having 16 houses on a uniform grid (Fig 2). This is surrounded by a less-dense region with 6 houses evenly spread along each of 8 major roads out of village (Fig 1). For geometric regions the roads on the north/south/east/west lines are 12km long (houses at 4, 8, 12km) while the diagonal roads are 9.6km long (houses at 3.2, 6.4, 9.6km). The black lines are roads, the green lines are driveways, and the village houses are all in the centre of their respective piece of land. 2
Fortunately, the local Council is very supportive, you can build/dig/hang what you want, but require any new infrastructure to be along the roads and house driveways only, you cannot go through backyards to cross property boundaries.
Every village home has a working phone landline (POTS) from one of the five ‘nearby’ exchanges (green in Fig 1), noting some might exceed the desirable 4km distance (it’s ok for a phone call!). On the roads heading out of the village there is no cabling in place yet. The houses along those roads each have a 500m driveway, for those in the village the driveways can be 250m or 700m long.
There’s 4G mobile phone coverage across the region from the big tower and antenna in the centre that can just reach about 20km in any direction. The exchanges and the 4G phone coverage provide connectivity back to the wider internet, you just need to reach them. The exchanges also have towers on top that you can take advantage of to hang any equipment, and you can even install additional towers if needed.
a) Describe (briefly) the various approaches that could be deployed and what a deployment would look like in each situation: a. FTTx/HFC cable – what kind of equipment and cables (copper/fibre) are needed where, and how much is needed. b. Compare them to some reasonable off-the-shelf wireless options. c. Your analysis should include expected downstream/upstream performance, and any limitations. Simple diagrams will be very helpful. b) Explain in more depth what you would recommend, and why. Highlight any assumptions or simplifications you need to make. It’s only a short first report for the organisation, they’ll need to go get a lot more data based on your advice. c) Estimate the deployment costs, using the following indicative pricing, for new stuff, for each design you propose. Note that not all the necessary equipment is priced here, so you should flag anything else you think is needed. You should also briefly describe what operational costs you might expect longer term (people, electricity, protection/repairs, etc.) and how to perhaps minimise them. (Think about what it would take to run your network for the next 30 years.) a. Fibre: $10/meter for the cable (1 pair of fibres), and $500 for terminating each end of the cable (both fibres). This includes both the purchase and trenching/hanging cost.
Not all houses are shown on the diagrams, just assume everything is symmetrically distributed. b. Copper: $3/meter for DSL/HFC-grade cable (1 pair of copper), and $150 for terminating each end. This includes both the purchase and trenching/hanging cost. c. Wireless broadband transmitters can be of two types: i. Omnidirectional = $20,000 each to cover a circle 10km radius, plus $500 per house. ii. Point-to-point links with 4km range = $600 at each end. iii. A new tower = $5,000, plus any cabling back to an exchange, plus whatever gear you want to hang on it. d. Converting one terminated fibre pair to one terminated copper pair (and vice-versa) = $50 e. Switching the signals from one terminated fibre pair onto 16+ copper pairs or 16+ fibre pairs is a more expensive $2,000 cabinet. (Yes, these numbers are extremely rough, but they do cover outdoor grade coax/UTP/fibre, they include much of the active equipment at each end, they magically support whatever kind of LANprotocol-specific equipment is needed for each technology, and they are powered by a hidden electricity grid that is conveniently available everywhere all the time. It’s a start!). d) Briefly explain: how might the design improve if you are allowed to use as many last mile options as you want? e) Briefly explain: how might the design improve if all the distances are halved, i.e. if the density quadruples?
Marking and Feedback
Reminder: There are four questions, with the last one containing multiple parts; please check you attempted all four before you submit.
For all questions, cite all your sources appropriately (use whatever citation style you are familiar with) and be clear where you are quoting and/or paraphrasing your sources. Lectures are not citable sources. Marks are given for your own work, not other people’s/machines’.
We’re looking for your ability to take the broad concepts covered in class, together with a good bit of research, to come up with your own summaries of the issues and opportunities that a lessexperienced person can still understand. Large-scale cut-and-paste slabs of information from various websites, even properly cited, are not going to score as well compared to a nice interpretation of the available information. It should be sufficiently technical to explain your proposals costs and benefits. There are many different ways to come up with a solution, don’t try and map out hundreds of possible options. Note, there is no single ‘right’ answer, and without a lot more information it is hard to even define the ‘optimal’ answer. The aim is to analyse the problem, develop a few simple potential solutions, and make a strong argument as to which options lead to the best outcomes. The marking for this assignment will be done via TurnItIn, which provides a total mark as well as some comments/suggestions. You can discuss with your tutor the breakdown of the marks you received.
Feedback: If there is a particular area or aspect of your work you would like specific feedback on, please mention that at the top or end of your assignment. Your tutor can then provide additional comments accordingly.
Have you covered each question with some breadth, i.e. the range of technologies, and demonstrated some insights – or have you just paraphrased some internet content (human/machine generated)? Even when citing others, it is your reasoning we want to see. Did you consider a variety of approaches to the designs? How many different ways can you deliver cabled or wireless connectivity? Which ones are less desirable, and why? Have you explained things to the intended audience, as described, or blinded them with jargon, or written it for a complete beginner?