Re: [802.3_4PPOE] Backfeed ad hoc - 3P detection

["Chad Jones (cmjones)" <cmjones@xxxxxxxxx>]

The only problem that I see in yours and Heath proposal is that even if we ask the PD to meet CC, detection signature and I class requirements under 3-pair, still we can’t force the PD to meet it if the PD doesn’t control external components to the PD that if backfeed is violated when the bridge is totally open and the 45K will be connected directly to the PD Rsig and Iclass. 

 

Isn’t this what we are trying to do? Specify an allowed current at the PI that would lead you directly to implement specific resistance internally? That’s what I see the group trying to do.

 

We are trying to set limits of behavior that will ensure interoperability based on the known operating conditions – one of them being these 802.3-2015 compliant devices already in the field that will unexpectedly present a 3P + 1P power channel to a PSE in classification. Dave Abramson has pointed out that we have 1mA guard bands in classification that likely explain why we haven’t seen any issues from the field, and that this margin gives us the solution (finally, a good result from the margin on top of margin that was built into the AF spec).

 

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: Thursday, May 17, 2018 at 6:22 AM
To: 4PPOE Reflector <STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx>
Subject: Re: [802.3_4PPOE] Backfeed ad hoc - 3P detection

 

---

To unsubscribe from the STDS-802-3-4PPOE list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-4PPOE&A=1