Re: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?

["Trowbridge, Stephen J (Steve)" <steve.trowbridge@xxxxxxxxxxxxxxxxxx>]

Hi Chris and Rob,

Just to play devil’s advocate here, I think it depends on the objectives agreed in the study group.

If the only stuff we have objectives to do for 200G are the same things we are doing at 400G with fewer lanes, sure, it all folds right in to P802.3bs. Specifically:

We would specify 8-lane CCAUI-8 and 4-lane CCAUI-4 C2C and C2M interfaces.

We would specify 200GBASE-SR8, 200GBASE-DR2, 200GBASE-FR4, and 200GBASE-LR4 PMDs.

But the flies in the ointment would be if we have objectives to build a 200GBASE-SR4, 200GBASE-CR4, or 200GBASE-KR4 PMD, which I think would be quite challenging on the current P802.3bs schedule.

 

Presumably the reason you think 100G belongs with 50G is that you assume this project needs to do interfaces like 100GBASE-SR2, 100GBASE-CR2, 100GBASE-KR2. But why wouldn’t you do, for example, a 100GBASE-DR interface in the P802.3bs project?

Regards,

Steve

 

From: Rob (Robert) Stone [mailto:rob.stone@xxxxxxxxxxxx]
Sent: Thursday, December 03, 2015 11:10 AM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?

 

Chris I agree with your observation, and I have been thinking the same thing with respect to the partitioning of the work.

 

It would seem that if possible, using the KR4 FEC for 50 and 100G would have a lot of benefits with respect to compatibility with existing MAC rates and 25G based technologies. I would expect that it is likely we will see co-existence of 25 and 50G / lane technologies within the same environment, and if so we should make an effort when defining the logic to enable straightforward low power connections between the different generations. Using end – end KP4 FEC would help facilitate that.

 

Thanks

 

Rob

 

From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Thursday, December 03, 2015 8:53 AM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?

 

The idea of rolling 200G into the 400G project is compelling. In prior discussions, we had rejected this as too late for 802.3bs TF, so it’s encouraging to see we are willing to revisit. One mental test of why this makes sense is to consider what we would have done in 400G Study Group if we knew what we know now. Given the CFI support, it could be argued that most people would have supported both 200G and 400G. If anything, 200G is more compelling.

However, the inclusion of 100G in the 400G project is much less clear. Several arguments can be made that it more naturally belongs in the 50G project. An important consideration is that for both 50G and 100G, backwards compatibility with existing 25G I/O interfaces is important. Specifically we will want 50G supported with 2x25G electrical I/O and 100G to be supported with 4x25G I/O (CAUI-4). This suggests that for 50G single wavelength and 100G WDM2 solutions, KR4 is the appropriate FEC. For both, this gives reasonable optical margin with PAM4 modulation. On the other hand, for 200G WDM4 KP4 is a better choice, same as for 400G WDM8.

Adding only 200G to the 400G project makes for much cleaner documentation modification. Broad market potential for 200G is the same as for 400G. We don’t need to introduce new justification which is required for 100G. Not having 100G, removes any dependence on any other project, so there is no need to discuss this.

 

Chris

 

From: John D'Ambrosia [mailto:jdambrosia@xxxxxxxxx]
Sent: Thursday, December 03, 2015 6:00 AM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?

 

Dear Task Force Participants,

This email is to make sure that everyone is aware of conversations happening in the 50/100/200G Study Group Phone Conference that happened yesterday – Dec 2.  There has been discussion at how the multi-lane 100G/200G solutions might be rolled into the 802.3bs project.  To that end – I gave a presentation at the conference call that looked at potential modifications / additions to our PAR / CSD.  See http://www.ieee802.org/3/50G/public/adhoc/archive/dambrosia_120215_50GE_NGOATH_adhoc_v2.pdf

 

I encourage everyone to review this presentation and consider the findings on the last few pages.  Individuals may wish to participate in the upcoming 50/100/200G ad hoc calls that Mr. Nowell has planned.  For more information see http://www.ieee802.org/3/50G/public/adhoc/index.html.

 

I will be working on the meeting announcement for the January interim, and anticipate that there will be a joint session of our Task Force with the Study Groups to further consider these implications.

 

Regards,

 

John D’Ambrosia

Chair, IEEE P802.3bs 400GbE Task Force