Re: [nsp] Few questions about ATM connections and ATM Traffic-Shapping

From: Stephen Sprunk (
Date: Fri Apr 05 2002 - 17:41:38 EST

Thus spake "Tommy" <>
> I have customer connected to my network via ATM OC3 card.

Via a carrier, or directly? That completely changes the context of your
questions below.


> And now I have few questions according this configuration:
> 1) Is any diffrence in using CBR instead of UBR
> in PVC configuration ? I think that 155mbps OC3 link can guarante
> in 100% 4mbit/s traffic. But CBR looks better...
> 2) Is any _good_ method to calculate Cell Rate for IP
> Mbit/s ? For example I'd like to calculate what Cell Rate is
> "true" 4mbit/s of IP packets for ATM PVC circut with
> aal5snap encapsulation ?
> 3) The cell rate set by CBR/UBR command on my PVC is only responsable
> for outbound traffic (packets transmitted to Customer) ? If
> yes, Can I traffic-shape inbound traffic (packtes transmitted from
> Customer) on this PVC ? Maybe some QOS rate-limit command ?
> 4) If between My router and Customer's router will
> be added ATM Switch. Where traffic-shaping must be done ? Still on
> Routers or only on ATM switch ? Or maybe on Routers and ATM Switch ?
> best regards, Tom

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