[c-nsp] how to validate cell rates?

[Clinton Work]

Gert Doering wrote:
> 
> Are the CDVT values specific to the configured VC types?  They claim
> a CDVT value of "750", though I'm not sure what to make out of it, or
> how to match this to Cisco config statements.

I have only used Alcatel ATM gear a lot. CDVT is supported on both UBR
and VBR PVCs. A CDVT value of 750usec is higher than the Alcatel default 
of 250 usec.

UBR parameters: Peak rate, Min Rate, CDVT
VBR parameters: Peak rate, Sustained Rate, CDVT, MBS, CLR

I try to avoid traffic shaping inside the ATM network on ATM PVCs 
because it causes so many problems when shaping mis-matches occur. If 
you own the edge equipment on each side of the ATM cloud you can enforce 
the shapping on the edge equipment. This usually works much better 
because the edge equipment can take into account packets rather than 
just ATM cells when enforcing the traffic shaping. You can adjust
the DSL port profile to train at a specific up/down rate to avoid
the use of PVC traffic shaping.

I'm not sure either what kind of cell variance you get from a Cisco UBR 
ATM PVC.