[c-nsp] tx-ring-limit tuning

[Beatty Lane-Davis]

Hi Akko,

> us to push the utilisation of the links above 75% without seeing any 
> performance issues?

You reckon you might be hitting the cell-tax wall?  
The utilization ceiling you'll hit will be related to the encapsulation
type you're using and the amount of ATM overhead your particular traffic
profile will create.

I know I'd be quite a happy man if I were to get 75% utilization with
our packet size distribution and AAL5SNAP encap combo.  Actually, I'd
probably be quite alarmed ;-)

Cheers,
b