课程概况
网络可谓无处不在，从Facebook这样的社交网络平台，到这些网站所运行的互联网技术，这些都成为了我们日常生活必不可少的一部分。
这门课中，我们将学习这些网络。我们尤其会去理解指导网络设计和可持续性的基本原理。我们将会看到，“分享很难”、“大众很聪明”这类简单短语能够很好地被用于总结很多网络理论。这些理论将被用来回答“3G如何在智能手机上工作”、“亚马逊上的平均评分有多大可信度”这类问题。这门课将不会使用繁重的数学知识，我们只要求加减乘除这类基本算术知识。我们会依赖动画、类比和故事作为我们的教学工具，以此代替复杂的方程式。
What makes WiFi faster at home than at a coffee shop? How does Google order its search results from the trillions of webpages on the Internet? Why does Verizon charge $15 for every GB of data we use? Is it really true that we are connected in six social steps or less?
These are just a few of the many intriguing questions we can ask about the social and technical networks that form integral parts of our daily lives. This course is about exploring the answers, using a language that anyone can understand. We will focus on fundamental principles like “sharing is hard”, “crowds are wise”, and “network of networks” that have guided the design and sustainability of today’s networks, and summarize the theories behind everything from the social connections we make on platforms like Facebook to the technology upon which these websites run.
Unlike other networking courses, the mathematics included here are no more complicated than adding and multiplying numbers. While mathematical details are necessary to fully specify the algorithms and systems we investigate, they are not required to understand the main ideas. We use illustrations, analogies, and anecdotes about networks as pedagogical tools in lieu of detailed equations.
All the features of this course are available for free. It does not offer a certificate upon completion.
课程将会涵盖如下主题：
手机需要多少电力进行传输？
WiFi在热点处为什么较慢？
谷歌如何为网页排名？
Netflix如何推荐电影？
互联网上是如何通信的？
课程大纲
周1
完成时间为 1 小时
Introduction
An introduction to what this course is about: the fundamentals behind social and technical networks.
5 个视频 （总计 39 分钟）, 3 个阅读材料
完成时间为 3 小时
Power Control in Cellular Networks
How is it possible that we can all communicate effectively without disrupting each other's calls, messages, or Internet usage? In this lesson, we
will take a look at some of the methods that have been developed for letting us "share" the air over which our phones communicate.
21 个视频 （总计 125 分钟）, 1 个阅读材料, 1 个测验
周2
完成时间为 2 小时
Random Access in Wifi Networks
In this lesson, we will investigate WiFi, another type of wireless network. Rather than having stringent power control algorithms as we saw for
cellular, WiFi relies on "random access" methods to manage interference among users in the same location.
15 个视频 （总计 98 分钟）, 1 个阅读材料
完成时间为 2 小时
PageRank by Google
In this lesson, we will take a look at PageRank, Google's famous algorithm for ordering the results on its search page. PageRank is a prime
example of how coming up with the right "ranking" of a set of items is a difficult yet important question in networking.
11 个视频 （总计 67 分钟）, 1 个阅读材料, 1 个测验
周3
完成时间为 1 小时
Product Rating on Amazon
The decision of whether or not to purchase something online is often driven by the ratings that previous customers have left for it. In this
lesson, we will take a look at Amazon's review system, and the see how "crowds are wise" is another important networking principle.
11 个视频 （总计 69 分钟）, 1 个阅读材料
完成时间为 2 小时
Movie Recommendation on Netflix
One of the perks of having a Netflix subscription is getting recommendations of movies to watch. Behind the scenes, Netflix uses powerful algorithms to determine which will be suggested to each person specifically. In this lesson, we will take a look at the main ideas behind these algorithms.
18 个视频 （总计 111 分钟）, 1 个阅读材料, 1 个测验
周4
完成时间为 2 小时
Midterm
1 个测验
周5
完成时间为 1 小时
Viral Videos on YouTube
What does it take for a video to become "viral" on YouTube? In this lesson, we will take a look at some of the key factors and models that have been used to explain this phenomenon. At the core is the notion of information cascade in a network, which is the counterpart to the wisdom of crowds.
12 个视频 （总计 77 分钟）, 1 个阅读材料
完成时间为 2 小时
Influencing People in Social Networks
In this lesson, we will continue with our theme of influence, now paying more attention to people's social networks. We will discuss different
ways of measuring importance and a popular model for influence spread in social networks like Facebook and Twitter.
13 个视频 （总计 89 分钟）, 1 个阅读材料, 1 个测验
周6
完成时间为 1 小时
Pricing Data
Data makes up a significant part of our cell phone bills. How do cellular providers set these price points? In this lesson, we will see how so-called
usage-based pricing schemes can send better signals than flat- rate, “buffet” schemes, leading to better sharing of the network.
11 个视频 （总计 76 分钟）, 1 个阅读材料
完成时间为 2 小时
Routing Traffic through the Internet
It is hard to overstate the impact that the Internet has had on society. In this lesson, we will overview the fundamental concepts behind the way
the Internet is designed. We will also take a look at routing, which is the process of determining how packets of information are transported.
22 个视频 （总计 83 分钟）, 1 个阅读材料, 1 个测验
周7
完成时间为 1 小时
Controlling Congestion in the Internet
The Internet has many important tasks to manage, like routing packets (discussed in the last module) and controlling congestion. This workload is modularized into different functional layers, each responsible for performing a different set of functions, as we will see in this lesson. We will also look at the principles of congestion control, managed at the transport layer.
18 个视频 （总计 77 分钟）, 1 个阅读材料
完成时间为 2 小时
It's a Small World
Six degrees of separation is a widely told story in popular science. How can it still be a "small world" with the enormity of the Internet today? It
depends on how the social networks are structured, and on how we search for short paths, as we will see in this lesson.
17 个视频 （总计 99 分钟）, 1 个阅读材料, 1 个测验
周8
完成时间为 2 小时
Final Exam
The final covers the last six lessons in the course (those after the midterm). Like the midterm, the questions are all multiple choice, and tend to
be easier than the homework questions but harder than the in-video quizzes.
