Re: [802.3_50G] 200GbE will be Different and Lower Cost/bit than 400GbE

[Ali Ghiasi <aghiasi@xxxxxxxxx>]

Brad 

I am also aware of QSFP like form factor with 8x interface where theoretically you can get to 400 GbE.  Again this is theoretical and far from what is feasible or practical, as point of reference 100 GbE QSFP module are just now going into production with power of ~3.5W!

400GbE in QSFP form factor requires 16 PAM4 CDR and possibly PMA mux if the optics operates at 100G/lane.  In 28 nm CMOS the 4x25G-50G PMA mux PD as reported by following ISSCC 2016 papers was 2.4 for just 2x50G!

4. 3.4  A 40/50/100Gb/s PAM-4 Ethernet Transceiver in 28nm CMOS 

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4.  

   Even in 16 nm CMOS the expected PD will not be <1.6 W and to support 400G just the CDR/PMA mux PD will be 6.4W.
   Even with 16 nm CMOS the right form factor for 400 GbE SMF is CFP8 or something comparable that support PD of 12 W.  
   
   
   By the time 400GbE SMF becomes reality in QSFP like form factor (next 4-5 years) the interface will be x4 based operating at 100G/lane.  The combination of SFP106 and QSFP106 will offer optimum cost and density, but we are couple of years way from it. 
   
   
   QSFP56 offers upgrade cycle to broad market with combination of QSFP56 and SFP56 by offering complimentary set of 200 GbE/50GbE where full range of PMD can be supported (Cu, MMF, PSM4, and CWDM4). 
   
   

Thanks,

Ali Ghiasi

Ghiasi Quantum LLC

Office (408)352-5346

aghiasi@xxxxxxxxx

On Mar 15, 2016, at 11:10 PM, Brad Booth <bbooth@xxxxxxxx> wrote:

Du,

CDFP2 is not the only option for 400G modules. There are other form factors in development that will provide 32 ports of 400G .

Cheers,

Brad

On Tue, Mar 15, 2016 at 10:56 PM, Duwenhua <duwenhua@xxxxxxxxxxxxx> wrote:

Hi, Jeffery & Scott

I agree with Scott on the comparison  between 200GE and 400GE.

Because port density is a important fact in data center.  Each line card can have 32~36 ports  of 200GE with QSFP56,  but only 16~18 ports of 400GE with CDFP2.

 

Du Wenhua

 

 

发件人: Jeffery Maki [mailto:jmaki@xxxxxxxxxxx]
发送时间: 2016年3月16日 13:47
收件人: STDS-802-3-50G@xxxxxxxxxxxxxxxxx
主题: Re: [802.3_50G] 200GbE will be Different and Lower Cost/bit than 400GbE

 

Scott,

 

For applications, we see this 4 to 1 ratio such as 200GE and 4 x 50GE OR 400GE and 4 x 100GE. What you do not consider is that the same base technology can do both, where that base technology is 50G lanes. The base technology factors are 4 & 1 OR 8 & 2. You are not accounting for server connects that use 2-lane interconnects.

 

We might argue that 400GE will not be at the sweet spot until it is made using 4 x 100G-lanes and server connects also use a 100G lane.

 

In this way, you do not have to get into saying 400GE is only needed for routers today. There are data center applications.

 

Jeff

 

 

From: Scott Kipp [mailto:skipp@xxxxxxxxxxx]
Sent: Tuesday, March 15, 2016 3:57 PM
To: STDS-802-3-50G@xxxxxxxxxxxxxxxxx
Subject: [802.3_50G] 200GbE will be Different and Lower Cost/bit than 400GbE

 

All,

 

I wanted to comment on some of the presentations that are coming out against 200GbE in the possibly final days of the NGOATH Study Group. 

 

As I showed in kipp_50GE_NGOATH_01_0116.pdf, 200GbE can be designed for low cost QSFP implementations from the start.  This makes 200GbE applicable to the low cost / high volume switch market while 400GbE will be suited for the high cost/ low volume router market.  200GbE will be a continuation of the successful, high volume progression from 40GbE QSFP+ to 100GbE QSFP28 to 200GbE QSFP56.  Highly parallel Ethernet interfaces more than 4 lanes wide like 400GbE have never reached high volume (more than 1M ports/year) and there is no reason to think this will change. 

 

According to Dell’Oro, more 100GbE switch ports shipped than 100GbE router ports last year for the first time.  This year, over 10X as many 100GbE switch ports are expected to ship than 100GbE router ports.  Routers ship low volumes of high speed ports initially, but switches overwhelm routers in port shipments when the technology is ready and the cost is low enough for switching.  This pattern of switching dominance is set to repeat again at 400GbE.  400GbE will ship for routers while 200GbE can come out of the gates in high volume like 40GbE.

 

Here’s a quick comparison of the differences between 200GbE and 400GbE:

 

Characteristic	200GbE	400GbE
Fits in QSFP Family of Modules	Yes, like 40GbE and 200GbE	No, requires 8 or 16 lanes
Supports Low Cost Copper	Yes, twinax and backplane	No copper here
Uses existing MMF cabling	Yes, 8 or 12 fiber MPO	No, requires new 32-fiber cabling
Supports low cost SMF modules	Yes, CWDM4 and LR4 in QSFP28	No, 8 lanes with tight wavelength spacing in higher power module
Target Market	Low cost switching	Premium routers

 

In booth_50GE_NGOATH_01a_0316.pdf, the presentation claims: 200G MAC to MAC provides no value.  I heard similar arguments against 40GbE in 802.3ba and 40GbE took off in switching in 2011 while 100GbE stayed high cost in routers until a 4-lane solution became available.  200GbE will add value by being lower cost/bit.  No Ethernet interface has proven to be low cost when it is highly parallel (>4 lanes).  Ethernet interfaces can sell millions of ports per year when they reach 4 lanes wide or less.

 

In nicholl_50GE_NGOATH_01_0316.pdf, the presentation claims “both a Standards and product viewpoint, 200GbE and 400GbE are likely to come out at the same time”.  I agree that the standards could come out at roughly the same time, but the products will be mainly different in character than in time.  High cost 400GbE will only be available in routers while low cost 200GbE will be in switches.  Go to any systems vendor’s website and there will be completely separate product lines for switches and routers.  Switches are for high volume and low cost while routing has very different and challenging requirements that are suited for high bandwidth deployments. 

 

I’m glad the objectives for 200GbE are already accepted by the Study Group.  I hope enough of you agree to keep 200GbE objectives in the project and prevent last minute changes with little justification beyond FUD.  End users will flock to 200GbE when they see a lower cost/bit performance - just like they did for 40GbE.

 

Regards,

Scott Kipp