The EIGRP SIA Incident: Positive Feedback Failure in the Wild
Reading a paper to build a research post from (yes, I'll write about the paper in question in a later post!) jogged my memory about an old case that perfectly illustrated the concept of a
Rehashing Certifications
While at Cisco Live in Barcelona this week, I had a chat with someone—I don't remember who—about certifications. The main point that came out of the conversation was this: One of the big dangers with
Learning to Ask Questions
A lot of folks ask me about learning theory—they don't have the time for it, or they don't understand why they should. This video is in answer to that question.
One Weird Trick
I'm often asked what the trick is to become a smarter person—there are many answers, of course, which I mention in this video. But there is "one weird trick" many people don't think
Responding to Readers: How are these thing discovered?
A while back I posted on section 10 routing loops; Daniel responded to the post with this comment: I am curious how these things are discovered. You said that this is a contrived example, but
Macrotasking
How do I get so much done? One way is to macrotask—the topic of this video.
Growing and Selling
A lot of people say just to save money, and watch it grow. There is more to life than just growing, though—you need to figure out what to sell, as well.
Learning to Ask Questions
One thing I'm often asked in email and in person is: why should I bother learning theory? After all, you don't install SPF in your network; you install a router or switch, which you then
What is a Tunnel
It's a bird! It's a plane! It's a... tunnel? In this video, I take on the age old question: what is a tunnel? Is it a protocol, or is it something else? This
Master of None
Should you be a johnny do-it-all, or so deep that no-one understands what you are saying? It's time to talk about the shape of knowledge—and how important it is to be intentional about
The Knowledge Mortgage
One of the common questions I get is this: I need to study to get a job, and I do not see how learning all this theory stuff is helpful. It's time to
Disaggregated, Hyperconverged, and Composed
The future of network is a big topic; while I have written about this, and spoken about it, in other venues, I thought it would be useful to make a two part video sharing some
The 40 hour work week
Before 1900 the average American worker worked more than 60 hours a week. A standard schedule was ten-hour days, six days a week. The only structural limits to working were lighting and religion. You stopped
Troubleshooting: Half Split
The best models will support the second crucial skill required for troubleshooting: seeing the system as a set of problems to be solved. The problem/solution mindset is so critical in really understanding how
Managing Attention
This is Ethan's post I talk about in the video on value and social media.
Troubleshooting: Models
How well can you know each of these four systems? Can you actually know them in fine detail, down to the last packet transmitted and the last bit in each packet? Can you
What Skill Should I Learn Next?
The perrienial question in network engeineering—or any engineering, really—is "what skill should I learn next? I take a shot at answering this question in this week's video.
Troubleshooting: Basics
It’s 2AM, the network is down, and the CEO is on the phone asking when it is going to be back up—the overnight job crucial to the business opening in the morning has failed, and
The Perfect and the Good
Perfect and good: one is just an extension of the other, right? When I was 16 (a long, long, long time ago), I was destined to be a great graphis—a designer and/or illustrator
Metacognitive
If I could choose just a handful of skills you must learn to be a successful engineer, being metacognitive would certainly be among them. What is metacognition? OOne of my favorite books on the virtue
Toxic Cultures and Reality
I have lived through multiple toxic cultures in my life. It's easy to say, "just quit," or "just go to HR," but—for various reasons—these are not always a good solution. For instance, if you are
On the ‘Net: Engineer Versus Complexity
https://www.youtube.com/watch?v=pvuQHkyh8sg&feature=youtu.be&w=600
BGP Tools for the DFZ (2)
In the last post in this series, I looked at the whois database to make certain the registration information for a particular domain name is correct. Now it's time to dig a little deeper into
BGP Tools for the DFZ (1)
Why isn't inbound load balancing working the way I expect? Why are users having a hard time reaching my web site? What is that strange advertisement I see in my local routing table, and where
Fabric versus Network: What’s the Difference?
We often hear about fabrics, and we often hear about networks—but on paper, an in practice, they often seem to be the same thing. Leaving aside the many realms of vendor hype, what's really the
Being an Effective Interviewer
One challenging aspect of being an engineer is interviewing other engineers. The interview process is rife with various problems, including the discomfort of interviewing someone who you perceive as being a better engineer than you
Self-Improvement Through Time Travel
There are some days I wish I could travel back in time and "fix" the time I wasted through an hour, a day, or a week working on something that really wasn't worth my time,
snaproute Go BGP Code Dive (3)
This week, I want to do a little more housekeeping before we get into actually asking questions of the bgp code. First there is the little matter of an editor. I use two different editors
Overvaluing Experience
"Sure, great candidate—so long as you just look at the paper. They don't have any experience." I wonder how many times I've heard this in my networking career—I wonder how many times this has been
What Language Should You Learn?
So you've decided, for all the reasons given in my last post on this topic, that you want to learn to code. The next, obvious, question is: what language should you learn? Remember the goal
Why you need to learn to code
We've all heard it by now: you'd better learn to code, or your network engineering career is going to die a quick (and potentially painful) death. Maybe you could still act as a briefcase carrier,
New Ways of Thinking
Rule 11 definitely applies to most new technology that's being hyped (and overhyped) in the networking world. But while some things stay the same, others actually do change. From one of my readers— Much of
Something Old, Something New…
Some time back a reader sent this question in— Is there some list of design fundamentals which were "true" or at least "good rules of thumb" in the past (2 months to 20 years and
Reaction: Should routing react to the data plane?
Over at Packet Pushers, there's an interesting post asking why we don't use actual user traffic to detect network failures, and hence to drive routing protocol convergence—or rather, asking why routing doesn't react to the
The Design Mindset (3)
So you've spent time asking what, observing the network as a system, and considering what has actually been done in the past. And you've spent time asking why, trying to figure out the purpose (or
The Design Mindset (2)
In a comment from last week's post on the design mindset, which focuses on asking what through observation, Alan asked why I don't focus on business drivers, or intent, first. This is a great question.
The Design Mindset (1)
How does a network designer, well, actually design something? What process do you use as a designer to get from initial contact with a problem to building a new design to deploying a solution? What
DoS’ing your mind: Controlling information inflow
Everyone wants your attention. No, seriously, they do. We've gone from a world where there were lots of readers and not much content, to a world where there is lots of content, and not many
Why you should care about complexity
If you look across a wide array of networking problems, you will see what is an apparently wide array of dissimilar and unrelated problems engineers deal with on a daily basis. For instance— Should I
Think visually: How graphics skills help engineers
Among all the skills I hear network engineers talk about, two that are often underrated are writing skills and graphics skills. There is some small slice of the networking world that is serious about writing
Fear itself: Thinking through change and turmoil
Fair warning: this is going to be a controversial post, and it might be considered a bit "off topic." Maybe it's just the time of year for fear. Or maybe it's several conversations I've been
Why aren’t you teaching?
There is an old saw about teaching and teachers: "Those who can, do. Those who can't, teach." This seems to be a widely believed thought in the engineering world (though perhaps less in the network
Assuming the worst is not the best assumption
It was too bad to be true, but I should have known that assuming the worst was not the best assumption. I was driving the "other" car, the Saab, on the way back from the
Personal Integrity
There is, on a daily basis, a choice you must make as a geek, as someone who is involved in technology — particularly in the world of computer networking. The choice we always face, every
Thoughts on Certifications
Should you stack up certifications, or should you learn something new? To put the question a different way: should Ethan get his CCDE? This week a couple of posts filtered through to my RSS feed
The Odd Hours Solution
For many years, when I worked out in the center of the triangle of runways and taxiways, I would get up at around 4, swim a mile in the indoor poor (36 laps), shower, grab
Multitasking, Microtasking, and Macrotasking
One of the most frustrating things in my daily life is reaching lunch and not having a single thing I can point to as "done" for the day. I'm certain this is something every engineer
Rule 11 is your friend
It's common enough in the networking industry — particularly right now — to bemoan the rate of change. In fact, when I worked in the Cisco Technical Assistance Center (TAC), we had a phrase that
Memorize — or Think?
I have several friends with either photographic, or near photographic, memories. For instance, I work with someone (on the philosophical side of my life) who is just astounding in this respect. If you walk into
Intellectual virtue and the engineer
On the 19th of January in 2009, Captain "Sully" Sullenberger glided an Airbus A320 into the Hudson River just after takeoff from LaGuardia airport in New York City. Both engines failed due to multiple bird
Out with the old: Make removing old technology part of your culture
Friday afternoon, late, and the new system is finally up. Users are logged in, getting their work done, and you've just received an email from the CTO (your boss' boss' boss' boss, probably), saying what
How the Internet Really Works
Way back in April of 2014, I started a series over on Packet Pushers called "How the Internet Really Works." This is a long series, but well worth reading if you want to try and
The Silo of Focus
How often, in our careers, are we told to focus on one thing at a time? I would guess I see some message about this, such as the image to the left in this post,
Liskov Substitution and Modularity in Network Design
Furthering the thoughts I've put into the forthcoming book on network complexity... One of the hardest things for designers to wrap their heads around is the concept of unintended consequences. One of the definitional points
Engineering Sense
Why didn't they ask Evans? For those who haven't read the famous Agatha Christie novel, the entire point revolves around a man uttering these words just before dying. Who is Evans? What does this person
It’s About Time
I guess I'm semi-famous. Or maybe I'm a moderately sized fish in a rather small bowl. Whatever the reason, a lot of people reach out to me for career advice. Which is okay, of course
Testing to the Cut Score (Certifications)
Tom has an interesting post over at The Networking Nerd on one of my favorite areas of discussion — certifications. To give you a sense — Perhaps raising the cut scores to more than 900
Good Enough
Looking at my desk in the late 1990's, that little haven where I came in early in the morning, and left ealry'ish in the afternoon, you'd see a catalog rack. Only it wasn't full of
False Dichotomy
Last week wasn't a good one for the cause of network engineering. United Airlines grounded flights because of a router failure, the New York Stock Exchange stopped trading for several hours because of a technical
Why certifications make me grouchy
While I support certifications, they also make me grouchy. Sometimes they make me really, really, grouchy, in fact — probably more grouchy than I have a right to be. You've probably heard the complaints a
Network scale is more than size
"Judge me by my size, do you?" I've had several discussions with people over the years about the concept of scale in the world of network engineering. Most often, when network engineers think of a
Why I Support Certifications
I'm betting that I could take my certifications off my resume and still have a fair chance at finding a job. It's a guess, of course, and I've never tried any sort of an experiment
Explain-a-holic (Communicate Clearly)
But just a couple of days ago, I was talking to someone about managing expectations in the IT world. How do you convince someone else to buy into a project? How do you get them
The right tool for the job
This last weekend I set a toilet, replaced five faucets, and put together the beginnings of a workbench. No, I've not resorted to working in "the trades," to make a living — I've been slowly
Waste Not a Moment (Time Management)
One of the legends surrounding people who get a lot done is they simply don't sleep. It's long been said that I have some number of clones who do part of my work, or perhaps
Eschew Obfuscation (Communicate Clearly)
Many years ago, I worked for a manager who had two signs on his desk. The first was a pencil with the words, "Pencil 2.0" printed above them. The rest of the sign went on
Own the Problem
In the late 1990's, I was on the routing protocols TAC team in Raleigh — which means I answered the phone, and said things like, "This is Russ from Cisco TAC, how can I help
In theory…
I don't normally peruse the reviews of my books — while I appreciate well thought out criticism, I normally find personal notes from folks who've read my books more profitable for mining out where I'm
The facts, while interesting, are irrelevant
Maybe my excuse should be that it was somewhere around two in the morning. Or maybe it was just unclear thinking, and that was that. Sgt P. and I were called out to fix the
Freedom to
Pardon me if I go a little bit on the philosophical side of life as a network engineer this week, but we need to have a little talk about freedom. This last week, Ethan wrote
Learning from Germanwings
On the 24th of March, the pilot of Germanwings flight 4U9525 into a field, killing everyone on board, including himself. This is a human tragedy — beyond what many of us will experience in our
Talk to the Dummy
You've hit brain freeze. It seemed like such a great idea at the time, but now that it's 2am, the application is down, and you can't find the problem, maybe it wasn't after all. Or
Act!
Part 1: Getting Inside the Loop Part 2: Orientation Part 3: Decide! Once you've observed, oriented, and decided, it's time to act. This might seem like a minor concept, but it's actually really, really hard
Decide!
Last week we talked about orienteering — using models and information to orient ourselves to what's going on in the network. This is part of the OODA loop, which we talked about two weeks ago.
Orientation
Quick — can you OODA? Last week we talked about the general idea behind the OODA loop; this week we'll cover one more step; next week we'll cover the last two steps, and then, in
Getting Inside the Loop
Metadata doesn't just apply to data science or protocols — it applies to engineering life. Think about the concept of epistomology — the study of how we know what we know — or the concept
Leaky Abstractions
Much of our life, as engineers, is about building, manipulating, and using abstractions. For instance, C is nothing but an abstraction on top of the actual register set provided by a particular processor. HTML is
On Losing
When I got off the phone, I knew I'd blown it. I'd gotten so wrapped up in the discussion on eVPNs that I might have crossed over that magical line between, "this is a really
Why Your Presentation Stinks (Part 2)
Last time, we talked a little about making certain your presentation has a point — or a porpoise, as the case might be. This time I want to talk about a few other common mistakes
Why Your Presentation Stinks (Part 1)
Powerpoint doesn't stink. Our presentation skills do. So how do we fix it? First, you must decide: what do I want this presentation to be? We've all seen the brilliant TED talks about new ideas.
Powerpoint Doesn’t Stink
"Presentations are just a waste of time." "Powerpoint stinks." "Can't we do something other than another long, boring, presentation?" "We should just ban Powerpoint." If I had a nickel for every time I've heard someone
The Degree or the Certification: Answering the Question
Okay, finally, I'm going to answer the question. For some value of the word "answer," anyway. I've spent three weeks thinking through various question you should be asking, along the way making three specific points:
The Degree or the Certification: You are Not a Widget
One of the things that bothers me the most about the Internet of Things (IOT) is how blithely we slip from talking about objects as things to people as things. Among all the things I
The Degree or the Certification: Learn to See
This week I was reading through various RSS feeds, and ran across a couple that fell within the scope of last week's topic. So, rather than moving on to more practical concerns, as I had
The Degree or the Certification
Having just come off doing a presentation on "being a great engineer," I can tell you what the number one question people asked was: Should I get a degree, or a certification? In fact, several
Write Like You Mean It (Part 2)
In the first part of this two part series, I talked about why it's important to learn to write — and to learn to write effectively. But how do you become an effective writer? I
Write Like You Mean It (Part 1)
Engineers are supposed to be able to gather information, arrange it in a way that makes sense, and then propose a solution that actually solves the problem at hand — right? So why is it
Jack of All Trades
"Jack of all trades, master of none..." How many times have you heard that in your life? In your career as an engineer? I've probably heard it hundreds of times, if not thousands, from working