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Re: [802.3_100G-OPTX] P802.3cu adjourned

Another approach that we have discussed is what we did for 100G ER4 in 802.3bs.

 

10km is defined as an Engineered link, and 8km as worst case fiber link.

 

Chris

 

Illustrative Link Power Budget

Description

400GBASE-LR4

Unit

Power budget

(for max TDECQ)

11

11

dB

Operating distance

8

10

km

Channel insertion Loss

5.8

6.3

dB

Allocation for penalties

(for max TDECQ)

3.7

4.7

dB

Additional insertion loss

allowed

1.5

0

dB

 

 

 

From: Chris Cole
Sent: Tuesday, July 23, 2019 10:14 AM
To: 'Brian Welch (bpwelch)' <bpwelch@xxxxxxxxx>; STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_100G-OPTX] P802.3cu adjourned

 

Brian

 

Excellent point.


The meaning of SR has changed over the years. At 10G it meant 300m. There was no objections raised when we reduced it to 100m or 150m for SR4.

 

Chris

 

From: Brian Welch (bpwelch) <00000e3f3facf699-dmarc-request@xxxxxxxx>
Sent: Tuesday, July 23, 2019 9:58 AM
To: STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: [EXTERNAL]: Re: [802.3_100G-OPTX] P802.3cu adjourned

 

John,

I’m not entirely sure what you mean, but if you look for instance at the 400G MMF task force they have different reaches for 400G-SR8 (100m over OM5) and 400G-SR4.2 (150m over OM5), and of course different reaches within each for different fiber types….

 

Brian

 

From: jdambrosia@xxxxxxxxx <jdambrosia@xxxxxxxxx>
Sent: Tuesday, July 23, 2019 9:50 AM
To: Brian Welch (bpwelch) <bpwelch@xxxxxxxxx>; STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_100G-OPTX] P802.3cu adjourned

 

Brian

This situation is very different.  When the reach was reduced in .3ba to 100m “S” was kept.  Yes that is true, but there were no other S instances at the speed with a different reach.

 

However, in this instance you also have LR4 – so one L does 10km and one does 8km? 

 

Not a good idea IMO.

 

John

 

From: Brian Welch (bpwelch) <bpwelch@xxxxxxxxx>
Sent: Tuesday, July 23, 2019 12:47 PM
To: jdambrosia@xxxxxxxxx; STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3_100G-OPTX] P802.3cu adjourned

 

If we do need to reduce from 10km (in my mind still a big if), I think keeping with “L” would be just fine. We have kept “S” for MMF solutions are the reach changed due to fiber restrictions….

 

Brian

 

From: John DAmbrosia <jdambrosia@xxxxxxxxx>
Sent: Tuesday, July 23, 2019 9:39 AM
To: STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100G-OPTX] P802.3cu adjourned

 

 

Chris,

Your response isn’t clear to me- are you suggesting that if the objective were reduced to 8km you would want to continue to use the LR in the name? 

 

I wouldn’t support this myself.  I look back to the confusion that was caused by LR10 10 years ago -  I remember presentations where the audience indicated that they thought LR10 would support the same reaches as 10GBASE-LR.  I see no reason why this would change now.

 

John

 

From: Chris Cole <chris.cole@xxxxxxxxxxx>
Sent: Tuesday, July 23, 2019 12:11 PM
To: STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100G-OPTX] P802.3cu adjourned

 

Hi Gary

 

Looks like this is an important consideration. I only focused on what it would take to change the objective within 802.3cu.

 

Changing the LR name would not be a good idea, so that would not be a suggested path.

 

Chris

 

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