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I believe there is strong case for using 200GbE for Data center networking when 50G serial technology moves into Server Interconnect. DC ToR switches, first using 40G (4x10G) and now 100G (4x25G) as Uplinks ports, will find 200G (4x50G) as a natural progression of the Quad architecture, requiring minimal changes to switch designs. The same can be said of Data center aggregation switches (Leaf / Spine). DC Networking links can evolve from 40G to 100G to 200G over the same optical cable infrastructure, e.g. SR4 over 8 fibers, as well as duplex fiber solutions, giving operators a seamless upgrade path. The number of “ports” a System can support when configured for 200GE will be 2x that of 400GbE; having a greater number of ports is a plus for certain DC architectures. The technical merits are substantive.
So, the CFI discussion should encompass both 50 and 200GbE; the future IEEE project should address 50/200GbE at the same time – working on one without the other leaves a gap, and will not serve the application entirely.
These are the port configurations for “1RU fixed switches” (Top of Rack) that will be enabled by 50G / 200G ports.
The uplink / downlink bandwidth ratio is 3:1 or 2:1, depending on 4 versus 6 QSFPs.
Note that this applies to any 1RU box, including Aggregation Switches, Routers (not just Server connections).
Today = 48 x SFP 10G downlinks + 6 x QSFP 40G uplinks.
Soon = 48 x SFP 25G downlinks + 6 x QSFP 100G uplinks.
Future = 48 x SFP 50G downlinks + 6 x QSFP 200G uplinks
Future (dream) = 48 x SFP 100G downlinks + 6 x QSFP 400G uplinks
I agree there is a lot of merit to standardize 200G as a partner with 50G serial IO and continue the factor of 4 down / uplink – especially given that the SI and module challenges seem relatively do-able.
One additional thought – if we agree that 50/200 makes sense, would it follow that 100 / 400 would also pair up? That would enable a two lane twinax DAC server interconnect paired with a 400G uplink. The 400G would be already covered in .bs, and the 100G may “come for free” with 200G, just less lanes?
So it would seem in my opinion that 50, 100 and 200G based on 50G IO would be relatively mainstream PMDs, and would merit discussion for inclusion (at the risk of project overload!).
And 50G SFP / 200G QSFP for Ethernet will have nice alignment and re-use with Fiber Channel roadmap for 64GFC SFP / 256GFC QSFP ….
These are great examples.
Standardizing 50G and 200G PMDs will continue the successful progression of single and quad channel devices for high volume datacenter applications.
Another great example of multi-lane 50G technology application was cited in your SMF Ad Hoc presentation survey of relevant papers from OFC 2015.
In this post-deadline paper Cisco authors presented a 2x50G PAM-4 (optical) 100Gb/s QSFP28 transceiver using Cisco 50G PAM-4 optics and Broadcom 50G PAM-4 (line side) PHY. Measurement results were for 10km SMF and 100m OM3.
I see opportunity for full spectrum of PMDs for both 50 GbE and 200 GbE including popular break out option with combination of QSFP56 and SFP56:
- SMF PSM4/FR/LR
Ghiasi Quantum LLC
On May 7, 2015, at 1:31 PM, John DAmbrosia <John_DAmbrosia@xxxxxxxx> wrote:
I would like to request clarification of your stated intent below. You state the CFI will focus on single lane 50Gb/s Ethernet. While I realize you are initiating this effort – in my opinion the discussion that I am seeing happen is essentially “n” by 50Gb/s per lane with 50GbE and 200GbE being discussed.
As this is a consensus building process, will you be allowing interested parties to bring presentations forward to state justification for why 200GbE should also be considered? Based on my conversations, I believe there are a number of individuals who would like these topics discussed together.
Could you also provide any more insight into what you are proposing for single lane 50GbE? Will this be like the .3by project – Backplane, Cu Twin-as, and MMF? Or is that a TBD in your mind that you hope to address during consensus building?
Thanks in advance for your answers.
I wanted to let everyone know that a number of people have started preliminary discussions that would lead towards having a Call-for-Interest on the topic of single lane 50 Gigabit/s Ethernet at a future plenary meeting of 802.3. If anyone is interested in helping and contributing, please let me know or talk to me In Pittsburgh. As we get further along, we will be sharing some of the plans and data we are gathering to support the CFI.