Avago’s Interesting Demos at OFC/NFOEC

As always, the top transceiver manufacturers were represented at OFC, but of the top three datacom transceiver providers, Avago Technologies stood out to me. They had two significant demonstrations:

1. Connecting a 40GBASE-SR4 Ethernet port using its QSFP+ to four standard 10GBASE-SR Ethernet ports with its SFP+ modules. On the surface, this seems pretty easy to do, until you realize that the specifications for the transmitters and receivers in these devices have are very different. The 10G devices could easily overpower the 40G receiver if it’s not designed to handle the higher power. Avago has solved this issue with its parts and hopes to be able to be interoperable with anyone’s transceivers in the near future.
2. A VCSEL-based 25G short-wavelength SFP+ working prototype. At first I was puzzled about this because I couldn’t figure out the application. Well, it turns out there really is none for the 25G part, yet, but showing that it could be done makes you realize that 32G Fibre Channel applications using the SFP+ may not be as far-fetched as we think. And, perhaps we can get a 100GBASE-SR4 (4x25G that isn't in the IEEE standard yet) solution soon.

Stay tuned for more on other developments announced or demonstrated at OFC/NFOEC.

OFC/NFOEC Data Center Cabling Short Course (SC358)

I'm headed to LA next week for OFC/NFOEC and my first order of business will be to teach a short course on transitioning your data center from copper to fiber. Here's a short description of what I'll discuss:

This short course is intended to help data center and network managers understand the value proposition of an all-optical data center. Topics that will be discussed include looking at basic data center network infrastructure design and hardware needs.  The course was developed with the TIA-942, Telecommunications Infrastructure Standard for Data Centers in mind, but will also address the fact that many data centers really have not used this standard in practice. Networking standards such as IEEE 802.3, Fibre Channel, iSCSI and InfinBand will be reviewed along with their applicability to certain aspects of the data center. Technology roadmaps and data center networking trends will be included as well as how to handle transitioning from lower to higher data rates within your data center. When it makes sense to implement fiber optics and what types of transceivers and cabling should be used for different scenarios will be presented. Other technologies such as Fibre Channel over Ethernet, RDMA (InfiniBand) over Converged Ethernet, IO virtualization and how virtualization and network consolidation will affect data rates will also be discussed. Detailed cost analysis of fiber versus copper in the data center will be presented considering not only equipment and infrastructure cost, but port and cabling density, power and cooling costs.  Also included will be analysis of whether it matters what vertical market a data center supports – for example, does a financial sector data center have different requirements than a higher-education data center? Several real-world case studies will be presented.

Hope to see you there.

SC10 and Optical Transcievers

It’s a beautiful time of year in New Orleans for the top supercomputing companies to show their wares. While I wouldn’t consider SC10 exactly the place to sell optical components, there were a few new developments there. SCinet – the network that is always built at the top HPC conference – boasted 100G Ethernet as well as OTu4. Alcatel-Lucent, Ciena, Cisco, Force10 and Juniper, among others donated equipment to build this network. Module vendors Avago Technologies, Finisar and Reflex Photonics contributed QSFP and CFP 40G and 100G devices to the cause.

Meanwhile, the Ethernet alliance was showing two demonstrations in its booth – a converged network running FCoE and RoCE over 40GigE and 100GigE. Nineteen different vendors participated in this demo that was run by the University of New Hampshire Interoperability Lab. Both CFPs and QSFPs were used in this demo.

Some of you may wonder why I would attend SC10. I keep my eye on the HPC market because it usually indicates where the broader data center market will be in a few years. And, in fact, even medium-sized businesses’ data centers with higher computational needs are starting to resemble small HPC centers with their server clusters using top-of-rack switching.

Most of the top optical transceiver vendors and even some of the smaller ones see this market as an opportunity as well. While InfiniBand still uses a lot of copper interconnects, for 40G and 120G, this is changing. QSFP was the standout for 40G IB displays and CXP AOCs were shown for 120G as well. Avago Technologies was the first to announce a CXP module at the show.

Some believe that the CXP will be short-lived because there is progress being made on 4x25 technologies – Luxtera announced its 25G receivers to go with its 25G transmitter that it announced earlier this year. But it will still be a few years before all of the components for 25G will be ready for system’s developers to spec in. Tyco Electronics had a demonstration at their booth showing it is possible to run 28G over eight inches of a PCB, but this was still a prototype. And Xilinx has announced a chip for 28G electrical transceivers that can be used with this board design. But, none of these devices are even being tested by equipment manufacturers yet and the CXP has already been adopted by a few. So I think the CXP may have more life in it than some people may think.

Other 10GigE Transceiver Markets – ER, LX4 and LRM

Some of you may have noticed that in my last post I neglected to talk about three other 10-Gigabit Ethernet variants – LX4, LRM and ER. That’s because the content was already long enough and I wanted to focus on the volume data center applications. Now, I’ll discuss the others.

10GBASE-ER runs over SMF at 1550nm for up to 40km. While there are a few service providers that might choose to do this, the vast majority of them choose WDM through the OTN instead. There may be some private networks that have need for this variant as well which is what prompted the IEEE include it in the standard. These transceivers are priced out of typical budgets for the average enterprise at over $4000.

10GBASE-LX4 was originally introduced to address installed base of FDDI-grade (not laser-optimized) MMF, but can also be used with higher-grades of LOMF as well as SMF. It uses CWDM to send four wavelengths (thus the X4) between 1269.0 to 1355.9nm running at data rates of 2.5 Gbps each. LX4 modules are available in both X2 and XENPAK form factors and from at least a couple of sources such as Emcore and Hitachi Cable. As you can imagine, because these devices have four lasers and four detectors with their associated electronics, they cost appreciably more than either the SR or LR transceivers. The module alone retails for about $2000, which means that the per port cost would probably around $2500. But, you most likely wouldn’t fill your switch with these modules of course; you would only use them as needed where you wanted to re-use existing installed fiber.

In response to the high priced LX4, 10GBASE-LRM variant was developed. It was enabled by chip companies such as Clariphy and Scintera with some new technology, electronic dispersion compensation (EDC), that could push 10G serial to longer distances on MMF. It took a while to develop the standard and the consequence was that LX4 really took much of the market it was intended for. However, once products were released and supported by the top-tier transceiver manufacturers (Avago, Finisar, Opnext), it has really taken much of the business away from LX4. LRM modules are now available in SFP+ packages as well, which clearly indicates the vendors think there will be an ongoing market for them.

One note of caution – if you intend to use either the LX4 or the LRM modules, you need to make sure that both ends of your channel have them, otherwise it won’t work.

Datacom Transceiver Vendors Transitioning into New Businesses

Have you noticed that it seems like all of the top datacom transceiver suppliers are transitioning their businesses? I’ve already talked about Avago’s new venture with its MicroPOD technology. They seemed to have supplanted Finisar as the technology leader in the space. Finisar has expanded its offerings into more telecom markets and JDSU is all but gone from the scene and focusing more on telecom again.

Finisar seems to be enjoying what may well be short-term success with its Laserwire offering. Since it is a non-standards based solution, it is difficult to believe it will become a mainstream one. While Finisar is offering other AOCs—C.wire (CXP-based) and Quadwire (QSFP-based), it does not seem to be participating in what seems to be a chip-to-chip optical interconnection revolution like Avago and Luxtera are (see previous posts for details) . Finisar used to be the technology leader in the optical transceiver space, it has veered off-course from that strength in preference for market diversification instead—now covering telecom and HPC standards-based solutions as an alternative. But perhaps this is the right move for Finisar, since it has not seemed to hurt its revenue position at all.

JDSU seems to be absent from the short-reach module market. It appears that the optical components giant has taken the technology that was developed at IBM, E2O and Picolight and thrown it away. Picolight was once a leader in parallel optics and, along with E2O, long-wavelength VCSELs. IBM pioneered v-groove technology and the oxide layer that enabled the next leap in speed and improved reliability for 850nm VCSELs. All of these technologies look like they are destined to die a slow, painful death after being acquired by JDSU. The company’s attention is clearly focused on its tunable technology and telecom applications, which is where, of course, it started. JDSU has never had a good reputation for assimilating acquisitions, so none of this should be a surprise. I was optimistic when JDSU bought these companies thinking that now these emerging technologies would be supported by a larger pocketbook. What was the reasoning for JDSU deemphasizing the technologies it acquired? Was it trying to get rid of short-reach competition in hopes that all optical networking would move towards long-wavelength devices? This would have been naïve; the likes of Finisar, Avago, MergeOptics and others would still be supporting 850nm optics and there remains a healthy market for them in enterprise networks and data centers—albeit a very competitive one.

According to JDSU, it is focusing on the LH and ULH versions of 40G and 100G first because it does not see the value in the CXP module for short-reach applications. For short-reach, it is focusing on QSFP+ modules, but development of these will take longer. The company claims it is not de-emphasizing its 850nm technology, but just focusing elsewhere first. I’m not so sure. Rumor has it, and I tend to believe that JDSU is looking for buyers for its short-wavelength business.

Luxtera’s Contribution to a Push for All-Optical Networks

Yesterday I wrote about Avago’s new miniaturized transmitters and receivers so today I’d like to introduce you to a similar product from Luxtera. Well known for its CMOS photonics technology, Luxtera actually introduced its OptoPHY transceivers first – in late 2009.

Luxtera took a different approach to its new high-density, optical interconnect solution. It is a transceiver module and is based on LW (1490nm) optics. Just like Avago’s devices, the transceivers use 12-fiber ribbon cables provided by Luxtera, but that’s really were the similarities end. The entire 10G–per-lane module only uses about 800mW compared to Avago's 3W, and they are true transceivers as opposed to separate transmitters and receivers. Luxtera is shipping its device to customers, but have not announced which ones yet.

In addition to the projected low cost for these devices, what should also be noted is that all of the solutions mentioned in the last three entries – Intel’s Light Peak; Avago’s MicroPOD and Luxtera’s OptoPHY – have moved away from the pluggable module product theme to board-mounted devices. This in and of itself may not seem significant until you think about why there were pluggable products to begin with. The original intent was to give OEMs and end users flexibility in design so they could use an electrical, SW optical or LW optical device in a port depending on what length of cable needed to be supported. You could also grow as you needed to – so only populate those ports required at the time of installation and add others when necessary. The need for this flexibility has seemed to have waned in recent years in favor of density, lower cost and lower power consumption. The majority of pluggable ports are now optical ones, so why not just move back to board-mounted products that can achieve the miniaturization, price points and lower power consumption?