Re: [802.3_SUPER-PON] PCS Proposal

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Claudio and all,

I just got to say, Whoa! From what I remember, your project is supposed to be defining a system based on 10GE-PON.

Why in the world would you not use the PCS from that speed? Keep in mind that practical implementations will use silicon that is already in the market, and that speaks the 10GE-PON protocol. If you adopt the 25G PCS, that will require people to redevelop a 10G EPON chip that speaks 25G PCS.

I appreciate that the 25GE-PON protocol looks so sleek, because it basically does away with the pretenses of looking like Ethernet. But consider this: all of the new functionality of the 25GE-PON protocol was driven by the multi-lane nature of that system, where packets are striped across several PONs and need careful reassembly. But, in SuperPON you just don’t have any of that. So you don’t need the fancy system.

So, I would humbly suggest that you focus on using the 10GE-PON PCS. Keep it simple, that is always the best advice.

Sincerely,

Frank E

From: Marek Hajduczenia <mxhajduczenia@xxxxxxxxx>
Sent: Thursday, August 22, 2019 8:46 PM
To: STDS-802-3-SUPER-PON@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_SUPER-PON] PCS Proposal

Well, it is simple IMHO – do not define two PCSes. Pick the higher performing one and move on with it. By the time you’re going into WG ballot, .3ca PCS should be well vetted and through the balloting process.

I understand you’re trying to hedge bets here, but it will backfire in actual deployments.

Marek

From: Claudio DeSanti <00000b528d17fa95-dmarc-request@xxxxxxxx>
Sent: Thursday, August 22, 2019 6:41 PM
To: STDS-802-3-SUPER-PON@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_SUPER-PON] PCS Proposal

Marek,

yes, that is exactly the problem we are facing.. Can we define a solution?

Thank you!

Claudio.

On Thu, Aug 22, 2019 at 5:37 PM <mxhaj79@xxxxxxxxx> wrote:

Thank you, Claudio

In Clause 74 is just a sublayer and not the whole PCS. I think interoperability wise, you’re setting yourself for problems – an OLT with one PCS will not understand the ONU with the other PCS.

Marek

From: Claudio DeSanti <00000b528d17fa95-dmarc-request@xxxxxxxx>
Sent: Thursday, August 22, 2019 6:24 PM
To: STDS-802-3-SUPER-PON@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_SUPER-PON] PCS Proposal

Hi Marek,

I see the possibility of an optional second PCS as something similar to clause 74, "Forward Error Correction (FEC) sublayer for BASE-R PHYs".

As stated in clause 74:

"The 10GBASE-KR and 40GBASE-KR4 PHYs described in Clause 72 and Clause 84 optionally use the FEC sublayer to increase the performance on a broader set of backplane channels than are defined in Clause 69. The FEC sublayer provides additional margin to account for variations in manufacturing and environmental conditions."

One PCS, the 10G-EPON one, is able to support all that we need for Super-PON. Enabling the option of a second higher performance one (the 25G-EPON PCS) goes in the same direction of the statement I just quoted, "provides additional margin to account for variations in manufacturing and environmental conditions".

From the Super-PON PMD perspective, replacing the 10G-EPON PCS with the 25G-EPON PCS has the same effect as enabling the FEC sublayer of clause 74: it goes from operating on a 64/66 encoded bit stream to a 256/257 encoded bit stream, at exactly the same clock. Slide 6 on the presentation attempts to convey this.

Although along the same lines, I understand that having the option of a second higher performance PCS goes a step further than clause 74. This is why I like people to think about it..

Thank you,

Claudio.

On Thu, Aug 22, 2019 at 4:02 PM <mxhajduczenia@xxxxxxxxx> wrote:

Claudio,

Since the deck does not speak to it … why would you want two solutions to the same problem? It seems odd at best to have two different PCS designs for the very same job

Marek

From: Claudio DeSanti <00000b528d17fa95-dmarc-request@xxxxxxxx>
Sent: Thursday, August 22, 2019 3:37 PM
To: STDS-802-3-SUPER-PON@xxxxxxxxxxxxxxxxx
Subject: [802.3_SUPER-PON] PCS Proposal

Dear Colleagues,

at today's P802.3cs call, this PCS proposal was reviewed: http://www.ieee802.org/3/cs/public/AdHoc/20190822-Super-PON_PCS_Proposal.pdf

No objections were raised by the people participating to the call, however it was recommended to have other task force participants to review it for further discussion at the next meeting.

Thank you,

Claudio.

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