Common operational misconceptions

Jack Bates jbates at
Fri Feb 17 15:14:00 UTC 2012

On 2/17/2012 1:05 AM, Carsten Bormann wrote:
> On Feb 17, 2012, at 07:50, Paul Graydon wrote:
>> what OSI means
> Yet another common misconception popping up:
> -- You can talk about the OSI model in the present tense
> (That said -- yes, it is still useful as a set of simple terms for certain combinations of functions.
> It is also still useful as a way to calibrate your gut feeling of what is going on in a network.
> Just never expect OSI terms to have a precise meaning in today's networks.
> 1978 is now a third of a century ago...
> If you need precision, you need to spell out what you mean in today's terms.)

Actually, I find it makes a perfect troubleshooting guideline in today's 
world; at least up to layer 4. I'm not saying it's a perfect match to 
troubleshooting a variety of MPLS problems, but it is a reminder that 
there are dependencies which must be checked.

In dealing with transport companies, the model is still a good 
representation of their service levels. It isn't uncommon to find their 
products defined as layer 2 services (ranging from tdm/sonet services to 
ethernet switching services), layer 3 services (often handled by their 
ISP department), and MPLS services (which can range from p2p transport 
to l3vpn).

Which brings up my final point. Until we quit naming things l2vpn or 
l3vpn, OSI still applies. :P


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