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(Effective) Habits of the Network Expert

For any field of study, there are some mental habits that will make you an expert over time. Whether you are an infrastructure architect, a network designer, or a network reliability engineer, what are the habits of mind those involved in the building and operation of networks follow that mark out expertise?

Experts involve the user

Experts don’t just listen to the user, they involve the user. This means taking the time to teach the developer or application owner how their applications interact with the network, showing them how their applications either simplify or complicate the network, and the impact of these decisions on the overall network.

Experts think about data

Rather than applications. What does the data look like? How does the business use the data? Where does the data need to be, when does it need to be there, how often does it need to go, and what is the cost of moving it? What might be in the data that can be harmful? How can I protect the data while at rest and in flight?

Experts think in modules, surfaces, and protocols

Devices and configurations can, and should, change over time. The way a problem is broken up into modules and the interaction surfaces (interfaces) between those modules can be permanent. Choosing the wrong protocol means choosing a different protocol to solve every problem, leading to accretion of complexity, ossification, and ultimately brittleness. Break the problem up right the first time, and choose the protocols carefully, and let the devices and configurations follow.

Choosing devices first is like selecting the hammer you’re going to use to build a house, and then selecting the design and materials used in the house based on what you can use the hammer for.

Experts think about tradeoffs

State, optimization, and surface is an ironclad tradeoff. If you increase state, you increase complexity while also increasing optimization. If you increase surfaces through abstraction, you are both increasing and decreasing state, which has an impact both on complexity and optimization. All nontrivial abstractions leak. Every time you move data you are facing the speed of serialization, queueing, and light, and hence you are dealing with the choice between consistency, availablity, and partitioning.

If you haven’t found the tradeoffs, you haven’t looked hard enough.

Experts focus on the essence

Every problem has an essential core—something you are trying to solve, and a reason for solving it. Experts know how to divide between the essential and the nonessential. Experts think about what they are not designing, and what they are not trying to accomplish, as well as what they are. This doesn’t mean the rest isn’t there, it just means it’s not quite in focus all the time.

Experts are mentally stimulated to simulate

Labs are great—but moving beyond the lab and thinking about how the system works as a whole is better. Experts mentally simulate how the data moves, how the network converges, how attackers might try to break in, and other things besides.

Experts look around

Interior designers go to famous spaces to see how others have designed before them. Building designers walk through cities and famous buildings to see how others have designed before them. The more you know about how others have designed, the more you know about the history of networks, the more of an expert you will be.

Experts reshape the problem space

Experts are unafraid to think about the problem in a different way, to say “no,” and to try solutions that have not been tried before. Best common practice is a place to start, not a final arbiter of all that is good and true. Experts do not fall to the “is/ought” fallacy.

Experts treat problems as opportunities

Whether the problem is a mistake or a failure, or even a little bit of both, every problem is an opportunity to learn how the system works, and how networks work in general.



  1. Elmer on 15 October 2019 at 5:13 pm

    Excellent write-up Russ. How does one start making the transition from following the book and the industry at large to making decisions based on data and expertise?

  2. Antsa Razanakoto on 19 October 2019 at 2:36 am

    Thanks for sharing!

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