Research: Bridging the Air Gap

14 May 2018 | Comments Off on Research: Bridging the Air Gap

Way back in the old days, the unit I worked at in the US Air Force had a room with a lot of equipment used for processing classified information. Among this equipment was a Zenith Z-250 with an odd sort of keyboard and a very low resolution screen. A fine metal mesh embedded in a…

The Universal Fat Tree

30 April 2018 | 5 Comments

Have you ever wondered why spine-and-leaf networks are the “standard” for data center networks? While the answer has a lot to do with trial and error, it turns out there is also a mathematical reason the fat-tree spine-and-leaf is is used almost universally. There often is some mathematical reason for the decisions made in engineering,…

Policing, Shaping, and Performance

28 March 2018 | Comments Off on Policing, Shaping, and Performance

Policing traffic and shaping traffic are two completely different things, but it is hard to know, in the wild, what the impact of one or the other will have on a particular traffic flow, or on the performance of applications in general. While the paper under review here, An Internet-Wide Analysis of Traffic Policing, is…

Side Channel Attacks in the Wild: The Smart Home

19 March 2018 | Comments Off on Side Channel Attacks in the Wild: The Smart Home

Side channel attacks are not something most network engineers are familiar with; I provided a brief introduction to the concept over at The Network Collective in this Short Take. If you aren’t familiar with the concept, it might be worth watching that video (a little over 4 minutes) before reading this post. Side channel attacks…

Reaction: AT&T’s Paper on dNOS

12 December 2017 | Comments Off on Reaction: AT&T’s Paper on dNOS

The AT&T White Paper: What they get Right, what they get Wrong AT&T recently published a paper on dNOS, an open, disaggregated, Network Operating System for any kind of hardware. They list three primary purposes for their effort at helping the networking industry build an open source dNOS: To improve the rate of innovation and…

Reaction: Science and Engineering

6 December 2017 | Comments Off on Reaction: Science and Engineering

Are you a scientist, or an engineer? This question does not seem to occur to most engineers, but it does seem science has “taken the lead role” in recent history, with engineers being sometimes (or perhaps often) seen as “the folks who figure out how to make use of what scientists are discovering.” There are…

Thoughts on Open/R

21 November 2017 | Comments Off on Thoughts on Open/R

Since Facebook has released their Open/R routing platform, there has been a lot of chatter around whether or not it will be a commercial success, whether or not every hyperscaler should use the protocol, whether or not this obsoletes everything in routing before this day in history, etc., etc. I will begin with a single…

A glance back at the looking glass: Will IP really take over the world?

6 November 2017 | Comments Off on A glance back at the looking glass: Will IP really take over the world?

In 2003, the world of network engineering was far different than it is today. For instance, EIGRP was still being implemented on the basis of its ability to support multi-protocol routing. SONET, and other optical technologies, were just starting to come into their own, and all optical switching was just beginning to be considered for…

Applying Software Agility to Network Design

30 October 2017 | 1 Comment

The paper we are looking at in this post is tangential to the world of network engineering, rather than being directly targeted at network engineering. The thesis of On Understanding Software Agility—A Social Complexity Point of View, is that at least some elements of software development are a wicked problem, and hence need to be…

Thoughts on Grey Failures

14 August 2017 | Comments Off on Thoughts on Grey Failures

Grey failures happen on a regular basis in all networks, but in larger networks the law of large numbers can take over and cause additional redundancy to actually reduce availability. This video considers some of aspects of grey failures.