Re: [RPRWG] Why are current RPR proposals too complicated to be deplyed and maintained by service providers????
Robert Castellano wrote:
> Alan,
>
> My understanding is that ABR is deployed in carrier networks. There
> are some ATM switches which map other ATM traffic classes to ABR at
> the edge to maintain tighter controls over traffic in the core of
> the network.
Bob, as some one who designed one such system, I do not believe that it is ATM
traffic classes that get mapped to ABR. Without going in to details such a
mapping would be problematic to say the least. The case is obvious for CBR, and
can be argued for VBR. Mapping IP/UBR and DiffServ to ABR traffic class also
presented a challenging client interface.
> The ABR flow control reduces buffering requirements
> in the core and moves the buffering out to the edge where traffic
> is dynamically shaped based on the ABR flow control. In that case
> ABR is not used as an end user service, but as a control technology
> for the other more popular traffic classes. Just because it's
> not visible as a service, doesn't mean that it's not hard at work
> for you.
I am not sure if the scheme was ever deployed anywhere. Complexity in design
and configuration simply did not justify the primary reason for such an approach
which was inter working with legacy ATM equipment.
Regards, Siamack
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