Hi Jeff,
I think this is a good question. In Slides#12 of
http://www.ieee802.org/3/bs/public/15_03/wang_t_3bs_01a_0315.pdf
it is already shown the limitation of KR4 FEC capability on 50G Electrical lanes
Based on current 802.3bs PCS/FEC architecture , if we want to use KR4 FEC in 50G and next generation 100GE, more work is needed and consider it another project
beside 802.3bs is the best alternative.
Thanks!
Xinyuan
发件人: Jeffery Maki [mailto:jmaki@xxxxxxxxxxx]
发送时间: 2015年12月4日
9:51
收件人: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
主题: Re: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?
Ali,
My concern is whether 50G electrical lanes defined for CDAUI-8 could be made to work with KR4 FEC too for 100GE applications. If CDAUI-8 gets lots
of coding gain somehow assigned to it such that KR4-FEC based 100G optics cannot work, then only the P802.3bs task force can modify its target to enable things. How to handle this is what we need to devise. Or, please convince me there is no problem.
Jeff
From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxx]
Sent: Thursday, December 03, 2015 2:39 PM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?
Mike/Chris/Steve/John
As one of the people that has been proponent of 50 GbE/200 GbE for one year, if we are not careful as Mike mentioned 802.3bs could end up getting delayed by a year+. The 400 GbE will be deployed 1st in the Routers/OTN
applications as soon the 802.3bs is stable, this market segment will happily deploy CFP8.
The 50GbE/200GbE is needed for next cycle of data center deployment based on 32 ports of QSFP56 or 6.4 Tb front plate capacity. The development of these type of SOC typically has long envelopment cycle and if we can
provide clarity on logical/PCS implantation of 50 GbE/200 GbE it will be a great service to the industry. We should definitely not try to define any 50/100/200 GbE optical PMD in the 802.3bs no matter how trivial the implementation you believe it is, as we
have seen with 100 GbE the market was more efficient with 100 GbE SMF PMD’s than IEEE would have been! What is winning in the market place is CWDM4/CLR4 and PSM4. The great cost reduction promised by serial 100G is already being met with CWDM4/CLR4 and PSM4,
to my knowledge not even a single serial 100 GbE module exist at least in our galaxy.:)
To facilitate development of next generation datacenter optimized SOC supporting 50/100/200/400 GbE, my suggestion is to limit expanding 802.3bs scope to items minimally impacting the schedule and providing greatest clarity:
- Add 50 GbE and 200 GbE MAC rate
- Define 50 GbE and 200 GbE FEC/PCS
- Define single and quad lanes operation of CDAUI-8 C2C and C2M
It would have been great to include in 802.3bs 50/200G backplane and Cu cabling, sorry it will be too disruptive and will delay the schedule by at least one+ year.
Thanks,
Ali Ghiasi
Ghiasi Quantum LLC
On Dec 3, 2015, at 12:15 PM, Mike Dudek <mike.dudek@xxxxxxxxxx> wrote:
It won’t be a slam-dunk to create a CAUI-2 using KR-FEC when the CDAUI-8 is using KP-FEC. Also if we are considering 100GBASE-DR or 100GBASE-LR2 those are likely to want the KP-FEC. I expect also that the 50G serial backplane and copper links are going to want the KP4 FEC. Ie the KP-FEC will be in any chips designed for 50G PAM4.
Mike Dudek
QLogic Corporation
Director Signal Integrity
26650 Aliso Viejo Parkway
Aliso Viejo CA 92656
949 389 6269 - office.
From: John D'Ambrosia [mailto:jdambrosia@xxxxxxxxx]
Sent: Thursday, December 03, 2015 12:00 PM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?
Jeff,
If I get your point here ? the only thing you are adding to what I already pointed out was the interaction between a x2 C2C with a x4 C2M.
Right?
John
From: Jeffery Maki [mailto:jmaki@xxxxxxxxxxx]
Sent: Thursday, December 3, 2015 2:37 PM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] New 50G/100G/200G SG - Potential Impact on 802.3bs?
I support what Chris is saying. In addition, I think we will need to examine support of existing 100G PMDs with a new optional electrical interface, the CAUI-2 (2x50G) C2M. Further, we should examine CAUI-2 C2C, where the C2M interface is CAUI-4. The desire for things to persist to work with KR4 FEC rather than requiring a new FEC code shall be high.
Jeff
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. Seehttp://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 seehttp://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