Category Archives: NetworkDetective

Techniques of a Network Detective: A New Series

Techniques of a Network Detective: A New Series

Put your detective hat on your head and your Network Detective badge on your lapel.  Introducing a new blog series – Techniques of a Network Detective.  This series will focus on the detective work (troubleshooting side) of our jobs as network engineers.

For over 30 years I’ve been playing in the “world of IT”. During those years there have been a lot of changes in our world. But through all that change, there has been a thread, for me, that has always remained constant. A thread and a passion that always seemed to be with me in every job over all these years.


Being a “Network Detective” is much the same as being a regular detective in many ways.  As a Network Detective we get put on a “case” – the “Case of the Missing Packets” maybe.  We go to the crime scene and try to find answers so we can solve the “who done it”


When a “crime” happens you need to be right there interviewing the suspects, surveying the crime scene, asking the right questions.  Trying to quickly figure out what is happening, where it is happening, and why it is happening.  This can be very difficult.   The “crime scene” is so large and our potential suspects pool so numerous and so diverse.  And, of course, with everyone doing more and more with less and less these days, there isn’t a lot of training on being a “Network Detective”.  For most of us there seems barely enough time to even keep up with all the varying technologies in IT these days.

….. enter the “Network Detective” series.

You might assume that this series and the subsequent blogs are going to focus on what to do once you get handed a new case.   The “save the day”… “be a hero” part.

  • Case gets handed to you
  • You find the suspects.
  • You question the suspects.
  • You find out “who done it”.
  • Problem Solved.

Case closed.  “Our work here is done”.  Right?

I mean… what more is there to being “on the job” as a “Network Detective”?



“On the Job As A Network Detective”

What I have found over the years is that there is a lot more to being “on the job” as a Network Detective.  There is all the work one puts in PRIOR to ever being called in on a case.   And all the work after the problem has been solved.


Think, again, about our law enforcement counterparts.  Prior to ever getting put on their first case there is “getting prepared”.  Learning… book reading… shadowing other detectives.  I mean… how can you possibly EVER differentiate a fact from a clue if you don’t have knowledge.  Knowledge is key.  The more knowledge you have… the better you will be “on the job”.

“How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?”  – Sherlock Holmes, The Sign of the Four

But without knowledge… how do you know what is “impossible”?

What about after the case is closed and the problem solved?  To be honest I believe our law enforcement counterparts are better at that than we IT people are.  I see so many people in IT quickly triage and fix the current problem… but there isn’t the time spent to do the “how could we have avoided this” questioning.

Techniques of This Network Detective


The above is the “big picture” of what are the 10,000 foot view of the techniques and methodologies of this Network Detective. Of course, while this series will be my techniques and methodologies as a Network Detective… obviously the techniques and methodologies that I’ve learned over the years have grown so very much by watching and learning from some truly great “Network Detectives”.

Excited for the series to start?  Can’t wait for the first installment?  🙂  Okay.. okay… here are 2 links to get your started.

vBrownBag: 2016 Cisco Live Berlin – Denise Fishburne – Techniques of a Network Detective
Troubleshooting Networks: Tips from a Network Detective

Addl Reference Material: CiscoLive Breakout BRKARC-2002: Techniques of a Network Detective


MPLS Fun in the Lab: Troubleshooting the MVPN Cloud – Part 6

MPLS Fun in the Lab: Troubleshooting the MVPN Cloud – Part 6

In MPLS Fun in the Lab: Add the Multicast in the Cloud – Part 5 we added the support in the cloud for multicast and for MVPN. As I mentioned in that blog, I intentionally left something out so we could have fun troubleshooting together. Please do know that what I left out is alsoContinue Reading

The Cure for Network Downtime is Not Just Technology

Design and tune your network all you want. But if your company doesn’t also have a culture of high availability, your High Availability and Fast Convergence is not complete. **This blog is a formatting cleanup and update to a previous blog I posted in 2011 on NetworkWorld. You just finished watching a CiscoLive session fromContinue Reading