Clay,
I would prefer to separate the L2 classification from the L1. After the
link comes up, an atPSE will start sending OAM frames, similarly an
atPD will start sending OAM frames. In both cases, receipt of OAM
frames indicates that L2 classification is in progress. There is no
reason that an afPD or an afPSE could not receive a firmware upgrade to
support L2 classification conforming to .3at.
Hugh.
Clay Stanford (LTC) wrote:
QUESTION:
In slide 4, when atPSE sees 1-1, 2-2, etc, the atPSE
assumes an afPD.
But if an atPD wanted, for example, to request
3.84W, does the atPD use the class 1-1?
In that case how does the atPSE know that the PD is
an atPD and not an afPD?
ANSWER:
Yes, an .atPD that wants 3.84, 6.49, or 12.95W would
use 1-1, 2-2, or 3-3 respectively.
In this case, the .atPSE does not know the .atPD is in
fact an .atPD. It thinks it is an .afPD. (The .atPD
does know the PSE is an .atPSE.)
Subsequently, if the .atPSE desires to use layer 2
classificaiton, it would need to poll the PD to see if
it responds. (Alternately, the .atPD could announce
to the PSE that it is an .atPD.)
clay
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