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Optical/IP

Chip Vendors Vie for Multimode Market

When the first 10-Gbit/s Ethernet switches were developed, the target customers were expected to be folk with new singlemode fiber installations. Now it’s turned out that there’s a lot of demand for running 10 Gbit/s over older, multimode fiber. As a result, vendors have been caught on the hop and are scrambling for suitable transceivers.

This state of affairs was underscored this week in a paper from Cisco Systems Inc. (Nasdaq: CSCO) at the Communications Design Conference (CDC).

The paper gave a status report on the two technologies being touted for transceivers for running 10-Gbit/s Ethernet over multimode fiber -- 10GBase-LX4 and electronic dispersion compensation (EDC) (see LX4 Gets Another Chance and IEEE Eyeballs Compensation).

Right now, LX4 is the only choice, according to Bruce Tolley, Cisco senior manager of emerging technologies. "There are no [EDC] products today that I can buy and ship to my customers," he says.

Neither LX4 nor EDC is exactly storming the industry, however. Molex Inc. (Nasdaq: MOLX/MOLXA) remains the only vendor actively committed to LX4, and that's based on a product line introduced in 2001. EDC, meanwhile, is only beginning its standardization effort in the Institute of Electrical and Electronics Engineers Inc. (IEEE) 802.3ae task force.

Better known for selling connectors, Molex hasn't been particularly vocal about its LX4 transceivers. But the company's been working on improving them.

As part of the CDC session, Molex group engineering manager John Dallesasse presented data showing that LX4 transceivers can reach even farther than expected, up to 1,400 meters on multimode fiber and 40 kilometers on singlemode, if the transceiver is properly tuned. (The LX4 standard calls for a 300 meter reach on multimode and 30 km on singlemode.)

Ben Willcocks, lead systems designer for Phyworks Ltd. delivered the case for EDC being cheaper and more compact. For example, an EDC chip could fit inside an XFP module, replacing the retimer chip that's required in there.

All that might be true, but Tolley says he'll remain skeptical until Cisco can look at the EDC devices in depth: "I've seen some of the demos, but I haven't seen parts in my lab, so I don't know how real they are."

Phyworks is expecting its first sample chips to complete manufacturing by the end of the year, Willcocks said. That puts it a step behind competitors such as startup Scintera Networks Inc., which is sampling now (see Scintera Networks Launches).

Separately, Tolley threw in a mention of the 10GBase-CX4 effort for standardizing 10-Gbit/s Ethernet over copper, a cheaper alternative to fiber. The CX4 standard is close to completion and chips are available -- and Cisco is interested. "I need to support legacy copper immediately," he says.

— Craig Matsumoto, Senior Editor, Light Reading
BlueWater66 12/4/2012 | 11:21:56 PM
re: Chip Vendors Vie for Multimode Market Why are we wasting our time discussing this. Molex is closing that division. Gone ... poof. Lightreading carried the press release.

The LX4 is dead. Cisco treats their vendors so poorly, that they deserve what they get. There is never any NREs, upfront commitments, real support, anything. The engineers are a nice group, but then the GSM group sets up endless roadblocks. Component companies trying to allocate development funds (or approve on-going activities like MolexGÇÖs MFO group) can't get any sense of potential return from companies like Cisco. They discount product forecasts to zero GǪ and shut them down.

In another 12 months Cisco will have to buy all of their products from a very very small pool of optical component vendors, (like JDSU). With luck, theyGÇÖll experience the same effects as DRAM customers in the early to mid GÇÖ90, when prices constantly went up and all of the power was in the hands of a very narrow supply base.

Lightreading should have researched this article better. The "angle" should have been that multi-mode LX4 is dead and lots of similar technologies from smaller companies (or small divisions like MFO) are also dying.

I don't work for Molex, but I can relate to the issues they faced (may they rest in peace).
materialgirl 12/4/2012 | 11:21:40 PM
re: Chip Vendors Vie for Multimode Market How far does 10Gbps go over copper? What kind of copper, Cat5? Can a signal make it across a room? What good is that? What use is the fiber put to? I believe that to be useful, the signal at least needs to make it to a POP, so it can be switched to another backbone for further transport.
rjmcmahon 12/4/2012 | 11:21:40 PM
re: Chip Vendors Vie for Multimode Market How far does 10Gbps go over copper? What kind of copper, Cat5? Can a signal make it across a room? What good is that? What use is the fiber put to? I believe that to be useful, the signal at least needs to make it to a POP, so it can be switched to another backbone for further transport.

By my judgement, these are the right questions to be asking.

Another lesson from Westinghouse's AC suggests that cities and municipalities will demand infrastructures, which not only transport bits long distances, but also provide for low cost extensibility to additional subscribers.
rjmcmahon 12/4/2012 | 11:21:31 PM
re: Chip Vendors Vie for Multimode Market rjmcmahon, you and materialgirl might want to try and arrange a visit to a NOC or POP.

I'd love to take materialgirl on a date to a NOC or a POP. Don't know that a materialgirl would enjoy such an evening, nor what my wife would say, but hell, I'd give it a try ;-)

Seriously, the only place I'm allowed in is a carrier neutral colo where a monthy fee is payed to rack some computers and connect to the real stuff. The next step is getting those computers connected to my premises which requires last mile connectivity. Unforutnately, the guys at the windowless COs will never open the doors no matter how loud the knock. My guess nobody is there, which makes me wonder, who is getting our monthly payments, and for doing what.
SIVROCX 12/4/2012 | 11:21:31 PM
re: Chip Vendors Vie for Multimode Market rjmcmahon, you and materialgirl might want to try and arrange a visit to a NOC or POP. You might find it opens one's eyes to the continued possible markets for high speed copper. While folks always want some distance with their interconnects, manytimes the boxes are on top of each other. Most POP's and NOC's are pre-wired with single mode fiber. Therefore CU and MM fiber both require the buyer to overlay one or the other. If someone could figure out how to use the existing SM jumpers (already in the trays) with a MM device then CU would be at a disadvantage. Waiting for the breakthrough.
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