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Dear 802.3cu Task Force Participants,
During the May 2019 interim meeting, 100GBASE-FR and 100GBASE-LR were adopted as names for 100G single optical lane PMDs. The alternative not chosen was 100GBASE-FR1 and 100GBASE-LR1.
This is exactly opposite of the 802.3ck Task Force, which at the January 2019 interim meeting adopted 100GBASE-CR1 and 100GBASE-KR1 as names for 100G single copper lane PMDs. The alternative not chosen was 100GBASE-CR and 100GBASE-KR. We now have inconsistent naming conventions in 802.3, which misses the point of having standards.
During the May meeting, I suggested that .3cu participants refrain from making this decision, to allow time to understand end user preferences, most importantly those of their datacenter operators. This is not a technical spec, so what matters most is operational convenience.
For single lane optics, having no digit after the letters made sense when there was no multi-lane alternatives. 10GBASE-LR and -SR were perfectly clear because there was no LR4 and SR4. The 10G four lane standard used different encoding so it was named 10GBASE-LX4, which meant there was no confusion with LR.
However, now that we have both single and multi-lane solutions, not using a 1 is confusing. The DR, FR, LR designation is used generically for any PMD with that approximate reach. If it is also used for a single lane PMD there is an ambiguity whether the reference is generic or specific. The table below shows this for FR and LR naming alternatives. Alt. A, which was adopted in May, results in an ambiguity between referring to the generic PMD with any lane count, and specific PMD with a single lane count.
PMD lane
count
2km alt. A
(adopted)
2km alt. B
10km alt. A
(adopted)
10km alt. B
generic
(any lane count)
FR
FR
LR
LR
1
FR
FR1
LR
LR1
2
FR2
FR2
LR2
LR2
4
FR4
FR4
LR4
LR4
8
FR8
FR8
LR8
LR8
Because what matters is the convenience of the end user, I asked volume end users of 100G optics about their preference, as committed to at the meeting. The table below has their positions.
End User
Single lane 500m, 2km, 10km
naming convention preference
Alibaba
DR1, FR1, LR1
Amazon
DR1, FR1, LR1
Apple
DR1, FR1, LR1
DR1, FR1, LR1
DR1, FR1, LR1
Microsoft
DR1, FR1, LR1
Tencent
DR1, FR1, LR1
There is no end user support for omitting the lane count from the name.
I will be raising this issue at the July meeting. I would like to suggest that everyone directly ask their customers what they prefer, so that we can be debate actual end user preferences, rather than aesthetics. We should also reconsider having contradictory naming conventions within 802.3.
Thank you
Chris
From: Mark Nowell (mnowell) <00000b59be7040a9-dmarc-request@xxxxxxxx>
Sent: Monday, May 27, 2019 9:25 AM
To: STDS-802-3-100G-OPTX@xxxxxxxxxxxxxxxxx
Subject: [802.3_100G-OPTX] P802.3cu Interim minutes posted
Dear Colleagues,
I hope you all had safe travel home from Salt Lake City.
The minutes from last week’s meeting are posted here:
http://www.ieee802.org/3/cu/public/May19/
Regards, Mark
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