On Feb 5, 2014, at 7:34 PM, Phil Mayers <[email protected]> wrote:

> If that's the case, do please spell them out.

Real sampling, thereby avoiding mls table overflow, with the resultant 
nondeterministic skew of statistics; seeing stats on dropped traffic; getting 
TCP flags so as to classify things like SYN-floods; and so forth.

Things pre-EARL8 Sups/DFCs simply didn't support, but which are vital for even 
the most basic traffic engineering, peering analysis, and troubleshooting 
purposes, much less security.

NetFlow on pre-EARL8 Sups/DFCs was a disaster; many folks who thought they were 
getting accurate statistics weren't due to mls table overflow, and all the 
above caveats regarding basic functionality really made it not very useful.

I can't tell you the number of folks I've talked to for the last 13 years or so 
who thought their own NetFlow stats were fine from EARL6 and EARL7, until they 
realized they weren't getting what they thought they were getting, and they 
couldn't even trust that due to mls table overflow.  I'm glad you were happy 
with EARL7 NetFlow, but that's a minority view, in my experience (both when I 
worked for Cisco and afterwards).

-----------------------------------------------------------------------
Roland Dobbins <[email protected]> // <http://www.arbornetworks.com>

          Luck is the residue of opportunity and design.

                       -- John Milton


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