Common operational misconceptions

Brandt, Ralph ralph.brandt at
Fri Feb 17 18:28:04 UTC 2012

To find counterfeit they teach you what good money looks like.  When you
are looking at a sniffer trace you are generally looking for something
that is not right. 

Ralph Brandt
Communications Engineer
HP Enterprise Services
Telephone +1 717.506.0802
FAX +1 717.506.4358
Email Ralph.Brandt at
5095 Ritter Rd
Mechanicsburg PA 17055

-----Original Message-----
From: Scott Helms [mailto:khelms at] 
Sent: Friday, February 17, 2012 11:24 AM
To: nanog at
Subject: Re: Common operational misconceptions

On 2/17/2012 10:18 AM, Steve Clark wrote:
> I agree with this 100%.
> Having worked with many people over the last 40 years, the good 
> trouble shooters understood how things
> were suppose to work. This helps immeasurably in determining where to 
> start looking.

This is dead on and why I always start classes with a refresher on the 
OSI model.  While the model isn't perfect it lets technicians and 
engineers construct a reasonable model of how things *ought* to be 
working.  While you certainly will run into devices that bend or even 
break the rules (sometimes for good reasons) its much easier to 
understand the exceptions if you know the normal operation for a 
repeater, bridge, or router.

Scott Helms
Vice President of Technology
ISP Alliance, Inc. DBA ZCorum
(678) 507-5000

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