Networking Notes - March 2021

Welcome to the March 2021 edition of the Networking Notes newsletter.

This newsletter gathers the most recent news about the evolution of the networking field. Its main objective is to inform the students who have read the Computer Networking: Principles, Protocols and Practice ebook about the evolution of the field.

You can subscribe to this newsletter.

You can contribute to this newsletter by adding a one paragraph news item as a pull request for next month’s newsletter

Open networking ebooks

The first edition of Computer Networking: Principles, Protocols and Practice was published more than a decade ago. At that time, I opted for an open-source ebook because the networking technology strongly depends on and contributes to open-source. Over the years, other textbooks were released as open-source ebooks as well. One example is Computer Networks: A Systems Approach, written Peterson & Davie. The first edition was published in 1996, but the recent ones became open-source. They also recently started a blog and are now publishing a newsletter. There are many ways to stay informed about the evolution of the networking field!

Internet policy

During the last months, we’ve observed an intense debate in Australia on whether large web companies such as Facebook and Google should pay to serve links (and summaries) of articles published on newspapers’s websites. Mark Nottingham wrote an interesting opinion about this debate on his blog.

Internet evolution

  • Researchers have studied the evolution of the Internet topology using various techniques including traceroute, BGP dumps, … A recent video summarises the last 20+ years of these studies with a nice visualisation of the evolution of the network topology.

  • In rural regions, it can be difficult to have access to broadband Internet services. These regions are often considered as too costly to serve by large network operators. In some of these regions, non-profit organisations manage to deploy high-speed networks in a cost-effective manner.

-In California, a 90-year old man was pissed off by his 3 Mbps DSL link. He bought an add in the Wall Street Journal to complain about his bad Internet access. This triggered many reactions and AT&T agreed to install a dedicated fiber to serve his house…

Network protocols

Application layer

Cloud gaming with actors such as Stadia, GeForce Now and PSNow could change how users play game. A recent study provides insight on how they three different cloud gaming solutions use the network.


  • DNS can be used over UDP, TCP, TLS or HTTPS. In a recent presentation, Alec Muffett explains how he used DNS over Tor to gain in privacy. Surprisingly, he did not suffer from the added latency.

  • several companies host open resolvers. The most popular ones are, or When using such a resolver, privacy can be a concern since your DNS requests reveal a lot of information about the websites that you visit. Quad9, the organisation responsible for recently decided to move to Switzerland to be subject to their more stringent privacy laws and thus protect their users.


  • Cookies are used for many purposes by HTTP servers. Some of these usages are legitimate, e.g. to store user preferences. Others help various companies to track users on a wide range of websites. Browsers like brave, Firefox and Safari try to counter this tracking by adding new features to make it more difficult for web trackers to track users. Recently, Firefox two new protections against these tracking cookies: total cookie protection and super cookies.


  • TLS is supposed to be an end-to-end protocol and only the client and the server should be able to decrypt the information exchanged. Some countries do not consider that the messages exchanged over the Internet should be private and have deployed techniques to decrypt the traffic of their citizens. Kazakhstan is one of these countries. In 2019, Internet users in Kazakhstan had to install a new state-owned root certificate that basically allowed the state to install proxies that intercept all TLS traffic. Note that different forms of tracking exist in other countries. Various companies track the behaviour of Internet users and a recent NYTimes article revealed the highly precise information that such companies could collect on smartphone users…

Transport layer


The IETF is finalising the specification of the QUIC protocol that combines the features of TLS and TCP on a protocol that runs over UDP. A recent article summarizes these standardisation efforts.

Network layer

Datalink layer

  • 5G networks are deployed in many countries. In some countries, there are debates on whether 5G should be deployed or not. In the meantime, China has already deployed more than half a million of 5G base stations

Physical layer

Software and tools

  • Bufferbloat is a term that is used by network engineers to indicate that some access links are equipped with too large buffers that cause performance problems for interactive applications. Routers use buffers to store packets before they are transmitted on the attached links. Routers should ideally be able to buffer packets during roughly one bandwidth-delay product to keep good performance. Unfortunately, some routers are configured to use all their available RAM to store packets. When their access link becomes overloaded, this creates various problems that are sometimes difficult to detect. The waveform bufferbloat test can be used to detect whether your access router suffers from such problems.

  • fping is another implementation of the standard ping tool that provides more features. A recent blog post explains some unknown features of this tool.

  • traceroute is frequently used by network engineers to debug routing problems. Students who are learning the basics of networking have sometimes difficulties to completely understand traceroute’s output. takes as input the text returned by traceroute and provides a web page with links to the intermediate routers, the measured rtt and the intermediate ASes. It also performs the reverse DNS lookup if needed.

  • Browsers support a wide range of extensions. Some of these are very useful. Others are questionable. A recent blog post looked at the performance impact of the most popular ones. If you care about web page download times, you should probably check your browser extensions…

Written on March 3, 2021