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Re: [802.3_NGECDC] Definition of "Breakout"?



John,

 

You asked for feedback. It is up to you to pick and choose what you shall do with the feedback. Use as you wish.

 

I think we are speaking past each other. I’m not trying to disagree with you. I think  you misunderstood me earlier.

 

  1. Your wrote: 802.3ba was not built on the back of the next lane technology.  Optically there was stuff happening at 40G, but electrically there was no effort inside of 802.3ba  to define 25G electricals.

    jmaki: The 802.3ba specification was not built on lane technology from 25G Ethernet. 25G Ethernet was not defined at that point. The 802.3ba project did decide to embrace a new lane technology, 25G NRZ optical lanes. There was no previous use in IEEE 802.3 specs. This statement stands independent of choice of electrical interface.

 

  1. And 802.3bs was not initially based on 50 Gb/s – that was a decision that happened once we got into TF.  Rather much of the earlier conversation was looking at a x16 solution.

    jmaki: I agree and this is why the project was hard to do. There wasn’t clear consensus to go with any particular lane technology and we ended up with PMDs based on 25G NRZ optical lanes, 50G PAM-4 optical lanes and 100G PAM-4 optical lanes.

 

Jeff

 

 

 

 

Non-Juniper

From: John D'Ambrosia <jdambrosia@xxxxxxxxx>
Sent: Thursday, August 20, 2020 12:34 PM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Definition of "Breakout"?

 

[External Email. Be cautious of content]

 

Tom / all,

While I appreciate everyone’s input – no one has suggested that the next speed of Ethernet is being pursued and being justified by the lower speed breakout rates. 

 

I noted clearly up front – this is a matter of defining the scope of the Study Group.

 

It has already been a matter of discussion that some have expressed the desire to look at being able to support the breakout application.  This creates the challenge for me to define the scope to allow that conversation to happen inside the anticipated study group.

 

However, allowing something as part of the scope does not mean it is the focus of the project or the scope of the future PAR.  These are decisions that the future study group would need to make.

 

Jeff –

Sorry but I need to give you a little bit of history lesson.

 

802.3ba was not built on the back of the next lane technology.  Optically there was stuff happening at 40G, but electrically there was no effort inside of 802.3ba  to define 25G electricals.

 

And 802.3bs was not initially based on 50 Gb/s – that was a decision that happened once we got into TF.  Rather much of the earlier conversation was looking at a x16 solution.

 

As I am fond of saying – Good ? for study group!

 

John

 

 

From: Huber, Tom (Nokia - US/Naperville) <tom.huber@xxxxxxxxx>
Sent: Thursday, August 20, 2020 3:19 PM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Definition of "Breakout"?

 

Hi John,

 

I agree with what Steve and Jeff have stated.  While having a higher rate may push companies to develop new pluggable form factors that system designers will then use in lower rate breakout applications in order to optimizes front panel real estate, as we’ve seen in the past (e.g.,  QSFP+ used to support 4x10G, QSFP28 used to support 4x25G), this is not a justification for defining the higher Ethernet rate.  If there is a market for higher density 100G or 400G plugs, the industry will build them whether or not there is an 800G Ethernet rate.   We need to be able to justify the higher speed Ethernet rate without appealing to alternative applications people will find the modules that support the higher rate.

 

Tom

 

From: Jeffery Maki <00000d5963b8071f-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Thursday, August 20, 2020 1:48 PM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Definition of "Breakout"?

 

John,

 

It helps. Some call this “channelization” where higher speeds of Ethernet are formed by the physical layer bonding provided by the virtual lane markers of the PCS.

 

I will avoid any highly loaded terms in the following. I will just use “lane.”

 

As Steve noted, we tend to build the next big project based on the latest and greatest lane technology to define the next higher speed of Ethernet and then subsequently refresh lower speeds of Ethernet with the new lane technology.

 

Now when there is doubt about the broad market potential of the next higher speed of Ethernet and any new lane technology is not ready for standardization, we look at bolstering the broad market potential for the new higher speed of Ethernet by pointing out that existing lane technology has broad market potential in supporting lower speeds of Ethernet.

 

A new project could define 800G Ethernet based on lane technology from the existing 100G and 400G Ethernet standards. An example would be 800GBASE-DR8. The reality is that the implementation may only be used as 2 x 400GBASE-DR4 or 8 x 100GBASE-DR and does nothing to prove 800G Ethernet has broad market potential. This is the confusion we garner from module volume figures that analysts publish. We don’t know how the module is put into use to know what speed of Ethernet it proves is being adopted.

 

Jeff

 

 

 

Non-Juniper

From: jdambrosia@xxxxxxxxx <jdambrosia@xxxxxxxxx>
Sent: Thursday, August 20, 2020 11:10 AM
To: Jeffery Maki <jmaki@xxxxxxxxxxx>; STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_NGECDC] Definition of "Breakout"?

 

[External Email. Be cautious of content]

 

Jeff,

Let me try a different tact –

For all of these instances – the specifications that would exist on each different pair or optical fiber should be the same –

  • AUI
  • Related PHYs
    • Backplane
    • Twin-ax cabling based on multiple different pairs
    • SR optics based on parallel MMF
    • DR optics based on parallel SMF

 

So the specification for each should be essentially the same – just varying the number of different pairs or fiber.

 

In the case of F/L/E we are looking at different specifications for the different number of lanes, as the associated mux/demux loss would vary, based on the number of optical signals being muxed /demuxed together.

 

Does this help ?

 

John

 

From: Jeffery Maki <jmaki@xxxxxxxxxxx>
Sent: Thursday, August 20, 2020 1:56 PM
To: jdambrosia@xxxxxxxxx; STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_NGECDC] Definition of "Breakout"?

 

John,

 

Let me ask a question first.

 

I your case (a), do you mean the individual interfaces will support ingress signals on separate time domains within +/-100ppm or are you simply looking at the fact that there is exact alignment with the PMD definition of a lower speed of Ethernet where any time domain support is an implementation detail?

 

Jeff

 

 

Non-Juniper

From: jdambrosia@xxxxxxxxx <jdambrosia@xxxxxxxxx>
Sent: Thursday, August 20, 2020 10:42 AM
To: Jeffery Maki <jmaki@xxxxxxxxxxx>; STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_NGECDC] Definition of "Breakout"?

 

[External Email. Be cautious of content]

 

Suggestion?

 

From: Jeffery Maki <jmaki@xxxxxxxxxxx>
Sent: Thursday, August 20, 2020 1:30 PM
To: jdambrosia@xxxxxxxxx; STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_NGECDC] Definition of "Breakout"?

 

John,

 

I chose my words carefully. As others have commented, they understand things in an operational sense from the implementations they see. Constricting the definition of “breakout” from its broader industry meaning does not seem like a good start. Perhaps use a different word that doesn’t come with so much “baggage.”

 

Jeff

 

 

Non-Juniper

From: jdambrosia@xxxxxxxxx <jdambrosia@xxxxxxxxx>
Sent: Thursday, August 20, 2020 10:22 AM
To: Jeffery Maki <jmaki@xxxxxxxxxxx>; STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_NGECDC] Definition of "Breakout"?

 

[External Email. Be cautious of content]

 

Jeff

Please keep my perspective in mind right now – I am trying to draft the CFI and scope of a new standard effort in the IEEE 802.

 

Not the scope of an implementation in an industry MSA.

 

Different requirements for each.  And I hope all recognize the challenge.

 

John

 

From: Jeffery Maki <jmaki@xxxxxxxxxxx>
Sent: Thursday, August 20, 2020 1:19 PM
To: jdambrosia@xxxxxxxxx; STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_NGECDC] Definition of "Breakout"?

 

John,

 

It is hard at this point to separate out conceptually the implementation from the abstract PHY. One can devise a superset module that supports a number of compliant PHY implementations with some being parallel fiber based and others being duplex fiber based. One’s choice of focus on your (a) or your (b) is their choice of favorite point of view. Both (a) and (b) are supported equally well by the module.

 

Jeff

 

 

Non-Juniper

From: John D'Ambrosia <jdambrosia@xxxxxxxxx>
Sent: Thursday, August 20, 2020 9:32 AM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Definition of "Breakout"?

 

[External Email. Be cautious of content]

 

All – conversation is good, and highlighting an issue that needs to be addressed.

 

There appears to be a trend of

  1. Breaking out a standards based PHY into the individual channels of the PHY into independent links
  2. An industry or vendor defined implementation that gangs a number of independent links together.

 

I can see a path to relating Item A to be within scope of Beyond 400 GbE effort.  I am not seeing that same path for Item B. 

 

John

 

 

 

From: Ted Sprague <tsprague@xxxxxxxxxxxx>
Sent: Thursday, August 20, 2020 12:25 PM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Definition of "Breakout"?

 

I’m used to the second definition (independent PHYs grouped in the same MSA, common interface for management).

 

In the first case, the module may support a unified mode or multiple individual modes – but only the second is referred to as ‘breakout’.

 

Thanks Ted

 

From: David Ofelt <00000d9f58951f93-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Thursday, August 20, 2020 8:50 AM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Definition of "Breakout"?

 

CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.

 

I think there are two different concepts that end up being colloquially referred to as breakout.  The first is that case you detaiil below- a set of parallel media lanes that can be grouped in various ways- either as a single unified PHY or as a number of slower PHYs.  The other case is a module that happens to hold a number of PHYs that are completely independent- like a QSFP-DD/OSFP module that has 4 x 100GBASE-LR optics. 

 

I’m Ok with declaring that “breakout” just covers the first case and your list is a good start at scoping the definition, but if we do that, I’d like us to figure out a name for the other case.  I find that when I talk to people about modules- it is important to clearly address both cases, since many folks have only one of the cases in mind and conversations can get confusing. 


I am also Ok with defining “breakout” to cover both cases, but then we can make that explicit in the definition.

 

--

DaveO

 

 

From: John D'Ambrosia <jdambrosia@xxxxxxxxx>
Reply-To: "
jdambrosia@xxxxxxxxx" <jdambrosia@xxxxxxxxx>
Date: Thursday, August 20, 2020 at 06:03
To: "
STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx" <STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx>
Subject: [802.3_NGECDC] Definition of "Breakout"?

 

[External Email. Be cautious of content]

 

All,

As I explore the scope for the Beyond 400 GbE effort, I have been having a number of conversations related to “breakout”

 

While we all discuss it – I have never seen some actual formal definition that is agreed upon within 802.3.  So I would like to get some input.

 

I am going to start with breakout actually does and solicit input before proposing some definition to potentially use.

 

I see break out of the following –

  • AUI
  • Related PHYs
    • Backplane
    • Twin-ax cabling based on multiple different pairs
    • SR optics based on parallel MMF
    • DR optics based on parallel SMF

 

FR / LR / ER optics – I don’t see as being part of breakout.

 

Thoughts?

 

John


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