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[RPRWG] [Fwd: BOUNCE stds-802-17@xxxxxxxxxxxxxxxxxx: Non-member submission from [Siamack Ayandeh <sayandeh@xxxxxxx>]]




Siamack and all others. Please make sure the your current
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Forwarded.

To: raj@xxxxxxxxxxxx
CC: stds-802-17@xxxxxxxx
Subject: Re: [RPRWG] Delays in physical layers
References: <D40034183F893A478D5FDEBBE34295B76FD7C9@xxxxxxxxxxxxxxxxxxx>
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Raj,

About time that some body asked.  It is certainly not milliseconds.  The
standard for ADM transit delays if I re call is limited to 50 [us] and
includes framing & grooming.  Channelized vs. unchannelized SONET/SDH
framing would of course give different numbers depending on
implementation.  Without getting into details a good rule of thumb may
be
a few micro seconds for OC-48 speeds.

Regards, Siamack

raj@xxxxxxxxxxxx wrote:

> I would like to know if anyone can shed some light on
> the different delays through the various physical layers
> chosen for RPR.
>
> The delay would the time it takes for a MAC to receive the first byte
> of a frame from the physical layer after the first byte is handed
> from the upstream MAC to its physical layer.
>
> The PHYs in interest are:
> GFP/SONET
> POS/SONET
> 64b66b/SONET (WIS)
>
> I am assuming that the delays in the PHY have two components.
> One associated with frame delineation and other with SONET framing.
>
> What would be the magnitude of these delays ? milliseconds ?
> microseconds? Would it interfere with any of the protection
> or fairness schemes?
>
> raj

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