Yair, we’ve be at this specification stuff for 15 years (you and I). Many, many times we have talked about how we don’t address what’s not addressed (and yes, that circular
text was intentional). If we listed everything that wasn’t specified, we’d never finish. I cannot support the addition of this statement.
Chad Jones
Tech Lead, Cisco Systems
Chair, IEEE P802.3bt 4PPoE Task Force
Principal, NFPA 70 CMP3
From: Yair Darshan <YDarshan@xxxxxxxxxxxxx>
Reply-To: Yair Darshan <YDarshan@xxxxxxxxxxxxx>
Date: Tuesday, June 12, 2018 at 10:00 AM
To: 4PPOE Reflector <STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx>
Subject: [802.3_4PPOE] Summary of the missing requirements for Transients for <=30uS
After seeing all the responses, I propose the following remedy to my comment below.
The concept is to make it similar to what we have in clause 33 which is no PSE requirements for transients below 30usec
Make the following changes:
"Transients less than 30
μs in duration may cause the voltage at the
PI to fall below VTran-2P. Requirements for Transients less than 30
μs
in duration are not specified. See 145.3.8.6 for PD transient requirements."
Other option is to delete “"Transients less than 30
μs in duration may cause the voltage at the
PI to fall below VTran-2P.” however I see the value with keeping this text but to complete explicitly the needed requirements which is in this case “no requirements are specified”.
Yair
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In clause 145 in the PD side we have clear requirements for what to do below 30usec and what to do between 30-250usec.
In the PSE side, it is only clear what to do between 30usec to 250usec.
Below 30usec the spec just giving us the info that the voltage can be lower than Vtran-2P but doesn’t say what to do in this case.
If for example we didn’t have this text "Transients less than 30 μs in duration may cause the voltage at the PI to fall below VTran-2P” as we don’t have in clause 33, that it will not be raising the question OK so what netx? What is the requirement from PSE in that case. Should we keep the power? Should we remove power? We don’t care? Or It is system decision? (i.e. may or may not remove power or “no requirements are specified” ? This is the problem that I am trying to resolve.
Yair
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