Computer and Communication Networks 2018 – 2019
Coursework Assignment
Section A (40 marks available)
Part 1: Network congestion is a serious performance issue, particularly where bandwidth is limited. Describe 3 approaches to congestion control that are implemented in packet- switched networks. (10 marks)
第1部分:网络拥塞是一个严重的性能问题，特别是在带宽有限的情况下。描述在分组交换网络中实现的三种拥塞控制方法。(10分)
Part 2: The profile of the traffic on a network can have a significant impact on the effectiveness of congestion control techniques. Pick two of the congestion control approaches you described in part one and explain how they would behave under i) constant, high-volume traffic conditions, and ii) overall low-volume traffic with short bursts of high volume activity. (20 marks)
第2部分:网络上的流量概要对拥塞控制技术的有效性有重要影响。选择您在第1部分中描述的两种拥塞控制方法，并解释它们在 i)恒定的、高流量交通条件下的行为以及 ii)具有短时间高流量活动的总体低流量交通下的行为。(20标志)
Part 3: A popular video conferencing provider is intending to implement congestion management on their network. Which of the approaches you described in part one would be most appropriate? Explain your answer
第3部分:一个流行的视频会议供应商打算在他们的网络上实现拥塞管理。您在第一部分中描述的哪种方法是最合适的?解释你的答案
Section B (60 marks available)
Using Python, C++, or JAVA, write a programme to simulate flood routing in a network with at least fifteen nodes. Each packet should contain a counter (n=10) that is decremented on each hop. When the counter gets to zero, the packet is discarded. Time is discrete, and each link can handle only one packet per time interval (i.e. only one packet in total may traverse the link in either direction). Nodes should include a buffer to queue any additional packets. Present your results in terms of the number of duplicate packets produced, and the congestion at each node, and suggest a possible solution for reducing this problem. You will be marked based on the following:使用Python、c++或JAVA编写一个程序来模拟至少有15个节点的网络中的洪水路由。每个包应该包含一个计数器(n=10)，在每次跳时递减。当计数器为零时，数据包被丢弃。时间是离散的，每个链路每隔一段时间只能处理一个数据包(即，总共只有一个数据包可以在任意方向穿过链路)。节点应该包含一个缓冲区来对任何额外的包进行排队。根据产生的重复包的数量和每个节点上的拥塞情况显示结果，并提出一个可能的解决方案来减少这个问题。你的评分将根据以下内容:
• Production of a well written report with clear explanation of the problem, and your solution; (10 marks)
制作一份书面报告，对问题和解决方案做出清晰的解释
• A clear description of the flooding algorithm implemented, and of the network topology used; (10 marks)
清晰描述所实现的泛洪算法，以及所使用的网络拓扑结构
• Graphical presentation of the results for each node; (10 marks)
每个节点结果的图形化表示
• Analysis and discussion of the results, and proposed solution for reducing the problem of duplicate packets; (20 marks)
对结果进行分析和讨论，并提出解决方案数据包重复问题
• Well-structured, working code. This should be submitted as a zip file alongside your
report. (10 marks)
结构良好的工作代码。这应该作为zip文件与您的报告。(10分
Your assignment should be submitted in the form of a technical report. The report should be single-spaced, have a minimum font size of 12 point, and be a maximum of 12 pages in length including all figures, appendices, and any code snippets. The cover page should include the module title, the date submission is due, your name, and your student ID.
All code should be submitted as a single zip file at the same time as the report, along with any instructions needed to compile and run the simulation.
报告
你的作业应该以技术报告的形式提交。报告应该是单行距的，最小字体大小为12点Report ，最大长度为12页，包括所有数字、附录和任何代码片段。封面页应包括模块标题、提交日期、您的姓名和学生证。
所有代码应该与报告同时作为一个zip文件提交，以及编译和运行模拟所需的任何指令。