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

David –

I don’t consider the second case breakout of an 800GbE PHY.  Using prior standards as an example – one would expect 800GBASE-LRx to be a WDM solution, where “x” wavelengths are optically muxed / demuxed.  What I believe you are proposing is an implementation where “x”  # of the lower speed are packaged together.  So the 800GbE PHY is not being broke out – the port implementation, which is not the focus of the standard, is.

 

John

 

From: David Ofelt <ofelt@xxxxxxxxxxx>
Sent: Thursday, August 20, 2020 11:50 AM
To: jdambrosia@xxxxxxxxx; STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Definition of "Breakout"?

 

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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