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Optical/IP

Conexant Shows Off Monster Chip

Earlier this week Conexant Systems Inc. (Nasdaq: CNXT) unveiled a crosspoint switch it claims can handle four times more traffic than any other single chip on the market (see Conexant Offering Tbit Chip).

This announcement could give Conexant a shot in the arm -- the communications chip maker has been taking a battering on the stock market (see Comm Chip Doldrums Ahead).

The CX20487 has 137 inputs and 137 outputs, each chattering away at speeds up to 3.3 Gbit/s. This allows the chip to process plain OC48 (2.5 Gbit/s) or OC48 with Forward Error Correction (2.7 Gbit/s) as well as other standards like Fibre Channel and gigabit Ethernet. One input and output can be used for equipment diagnostics instead of switching, if desired.

This is a significant development for manufacturers aiming to create large optical switches because it will enable them to build switches using one half to one sixth the number of chips that it took previously, according to Ray Fontayne, marketing manager for the ICON (Integrated Circuits for Optical Networking) division of Conexant. In fact, Fontayne claims that Conexant's chip can be used in a three-stage Clos architecture to implement a non-blocking switch fabric for up to 18,496 ports (that’s input plus output ports).

That's certain to help make switches with electrical cores more attractive than those with optical cores -- at least as far as OC48 is concerned.

Conexant also claims that its switch is a leader on a second front: power consumption. Fontayne claims that the company has always been ahead in this respect. "When we launched our 68x68 switch the power consumption was eight watts, and our nearest competitor was at 28 watts. Today, they [the competitors] have brought it down to 12 watts. This latest switch [which has a power consumption of 9.125 watts] just ups the ante again," he says.

To put this into perspective, it would take four 68x68 switches with a total power consumption of 48 watts to provide the same switching muscle as Conexant's 136x136 device. That's 48 watts, as opposed to just 9.125 watts.

But there is a drawback. Having a single, huge switch chip is putting all your eggs in one basket. "The chips are pretty reliable, but if one of the gates went bad, you'd have a failure on a lot more channels," Fontayne points out.

"The key challenges in the development of this colossus of a switch were the packaging and integration." It took over $1 million to develop the package, he adds.

First challenge: there are no off-the-shelf packages available for bit rates as high as 3.3 Gbit/s.

Second: chip density. Instead of using wire-bonding -- individually connecting every input and output on the chip to the package using a fine gold wire -- Conexant used a new technology called flip-chip bonding. Connections are made by solder bumps on the chip surface, which makes it possible to pack more of them onto the chip. The chip is then flipped upside down and bonded directly to a ceramic substrate.

The division that makes this chip, which is part of Conexant's Internet Infrastructure Business, is due to be spun off later this month, with the goal of raising $100 million (see Conexant To Split, Launch IPO). The Internet Infrastructure Business had product sales of $579 million in 2000 -- Q1 2001 results for the company are due out tomorrow.

In Wednesday morning trading Conexant rose 0.88 (4.4%) to 20.72 — Pauline Rigby, senior editor, Light Reading, http://www.lightreading.com

Pauline Rigby 12/4/2012 | 9:00:35 PM
re: Conexant Shows Off Monster Chip Fontayne also told me that Conexant has an OC192 crosspoint switch under development. Should the optical switch core guys be worried?
wdog 12/4/2012 | 9:00:32 PM
re: Conexant Shows Off Monster Chip The guys who think all-optical switches are going to completely replace electronic switches should have always been worried. All-optical switches have a place in the network, to replace fiber patch panels, other than that everythink else can be done better and at a lower cost by OEO switches. I can't think of a single place in the network where all-optical switches with 1000s of ports make any sense.
fotonphun 12/4/2012 | 9:00:18 PM
re: Conexant Shows Off Monster Chip >> "I can't think of a single place in the network where all-optical switches with 1000s of ports make any sense."

May I suggest looking at the article by Paul Green in the January 2001 issue of IEEE Communications? IMHO the case for a transparent all-optical network with all-optical switches is quite compelling if the growth in demand and data rates and the collapse of the network layers into IP over glass are considered.
fiber_r_us 12/4/2012 | 8:59:49 PM
re: Conexant Shows Off Monster Chip I have read this article, and it makes little sense for any practical networks that I have ever built. Paul's premise is that everything should be an optical wavelength between edge routers. Most metro areas have 10,000s of metro edge devices. Creating a wavelength (i.e. a circuit)between some partial mesh of all of the different routers in all of the metropolitain areas would require 10s of millions of wavelengths and a call-processing load that would make the PSTN look puny by comparison. This would be similar to an ATM architecture of similar scale. I think the industry has proven that building circuit(wavelength)-switched networks of this scale is not practical for the data world which is inherently packet-based.

I agree that all-optical switches with 1000's of ports are only slightly more useful than a patch-panel of similar size. So, if said all-optical switches can only be priced like patch-panels, then they would have a great market.
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