[c-nsp] Pix performance

[Dan Shalinsky]

Hi,

I believe that ESP adds around 20 bytes to the standard TCP header.  That
being said, it won't significantly affect throughput by increasing
overhead.  The throughput limitation is more due to the encryption process
being CPU intensive.

I can't find any pps specs on a 501, but I would think it should be able to
push more than 1200pps and 0.5 mbps.  For sure, it's not an overhead
problem.  HTH.

Regards,
~Dan