Common operational misconceptions

Holmes,David A dholmes at
Thu Feb 16 19:41:17 UTC 2012

With telcos increasingly implementing Metro Ethernet Forum (MEF) networks, I have found that telco technicians tasked with maintaining and operating these carrier Ethernet networks appear to disregard common high availability practices. For instance, after diagnosing a routing protocol neighbor flap (consistently 20-30 seconds) and isolating the problem to the carrier MEF network, the carrier technician told me that the problem was a spanning tree convergence that took their primary and back-up links down during convergence, but that "this is no big deal because the network was only down for 20-30 seconds".

-----Original Message-----
From: John Kristoff [mailto:jtk at]
Sent: Wednesday, February 15, 2012 12:47 PM
To: nanog at
Subject: Common operational misconceptions

Hi friends,

As some of you may know, I occasionally teach networking to college
students and I frequently encounter misconceptions about some aspect
of networking that can take a fair amount of effort to correct.

For instance, a topic that has come up on this list before is how the
inappropriate use of classful terminology is rampant among students,
books and often other teachers.  Furthermore, the terminology isn't even
always used correctly in the original context of classful addressing.

I have a handful of common misconceptions that I'd put on a top 10 list,
but I'd like to solicit from this community what it considers to be the
most annoying and common operational misconceptions future operators
often come at you with.

I'd prefer replies off-list and can summarize back to the list if
there is interest.


This communication, together with any attachments or embedded links, is for the sole use of the intended recipient(s) and may contain information that is confidential or legally protected. If you are not the intended recipient, you are hereby notified that any review, disclosure, copying, dissemination, distribution or use of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by return e-mail message and delete the original and all copies of the communication, along with any attachments or embedded links, from your system.

More information about the NANOG mailing list