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en4bz

http://www.cwdm4-msa.org/

No where does this mention Facebook as a founding member. This dates back to at least 2015.

> We created a 100G single-mode optical transceiver solution, and we're sharing it through the Open Compute Project.

What gives? Looks to me like someone may be taking more credit than they deserve.

EDIT:

> The starting point for this specification is the CWDM4 MSA, a standard that was agreed upon in 2014 by several optical transceiver suppliers. It uses a wider wavelength grid (CWDM = 20 nm spacing) and, for many of the different technology approaches, does not require a cooler inside the module to keep the laser wavelength stable.

So Facebook took something that already existed. Tweaked it slightly by relaxing the constraints so that it works in the data-center only.

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4 x 25Gbps has been around for years but in larger form factors like CFP, cfp2, etc. The main difference here is they're using commodity lasers from China and Taiwan sources with prism to do 4 x 20nm width channels between qsfp28 optics. For reference: https://en.wikipedia.org/wiki/QSFP

The next step down in size will be to sfp/sfp+ dimensions. I can see it coming, a qsfp is already a lot smaller than a first generation 100GbE CFP.

Facebook has really excellent marketing for their hardware engineering efforts.

The big difference is that it is lower cost than the 4x25 cwdm msa because it is specced for 500m reach through normal g.652.d singlemode and a reasonable number of clean, properly terminated sc and lc/UPC patch panels. Not specced to work at 2000 metres.

I guess the real question is do these cost savings actually save them money in the long run? Considering they had to do all the extra engineering work. Or is this just to thumb the big manufactures? Just another case of NIH syndrome?

If you have hundreds of optics and the difference is $1100 vs $2000 per unit, that could be $180,000 to $200,000 saved. Enough for the cost of one serious core router (half of a twin pair) capable of 400Gbps full duplex per slot. 500m should be more than enough for any optical path within a flat horizontal datacenter.

Facebook didn't do any extra engineering work, they just specced less sensitive Rx parts with the optics OEMS , and 1dB less powerful Tx.

> Facebook didn't do any extra engineering work...

I guess that depends on how you define "engineering."

They're basically trying to create a new class of transceiver. It remains to be seen if this will take off or not, but since it is part of the OCP effort, the chances are good that it will be taken seriously by QSFP vendors.

OCP is generating a lot of activity and change on the networking side. Whether it just becomes a race to the bottom where only the giant suppliers survive or whether it creates a new eco-system with more players and interesting technology remains to be seen.

I think it's great that a data center operator is willing to relax their requirements. For too long we've been designing against telecom specs and operating environments.

I think in order to bring more OEM vendors in we need to see the other big players to also accept the relaxed specs.

Hopefully, we don't end up with another dozen different 100G or 200G MSAs that work from 15-55C.

I'm also curious what the pricing difference is for a CWDM4 transceiver and the OCP version.

I would guess the NRE to develop either is similar and that the design for either is almost the same. Perhaps Facebook is just trying to get the optics cost down by negotiating discounts on the non-yielding MSA parts that would have otherwise had to get thrown out?

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