Conexant Systems unveiled this month a crosspoint switch it claims can handle four times more traffic than any other single chip on the market.

This announcement could give Conexant a shot in the arm -- the communications chip maker has been taking a battering on the stock market. It hit a 52-week low of $12.62 earlier this month, down from a 52-week high of $132.50 last February.

The CX20487 has 137 inputs and 137 outputs, each chattering away at speeds up to 3.3G bit/sec. This allows the chip to process plain OC-48 (2.5G bit/sec) or OC-48 with Forward Error Correction (2.7G bit/sec) 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 Closed Architecture to implement a nonblocking 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 OC-48 is concerned.

Conexant also claims that its switch is a leader on a second front: power consumption. Fontayne claims that the company always has 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," he says, adding that it took more than $1 million to develop the package.

Packaging was a challenge because there are no off-the-shelf packages available for bit rates as high as 3.3G bit/sec.

Chip density posed a second challenge. 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. The Internet Infrastructure Business had product sales of $579 million in 2000.

» posted by ITworld staff

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