Velio Thinks Big on Optical Switches

Startup Velio Communications Inc. is planning to announce a chip on Monday that will help vendors build even bigger optical switches with electrical cores.

Velio's VC3003 chip is a 140x140 crosspoint switch with port speeds of up to 3.2 Gbit/s, giving it nearly a terabit of aggregate bandwidth. It can be used on its own for crossconnecting wavelengths, or as a building block for constructing more complex, packet-based switching fabrics.

In terms of port-count potential, Velio's hit a new high. In a three-stage Clos configuration its chip has the potential to support a system with up to 9800x9800 ports -- though such a system would take up three telecom equipment racks. In higher-order Clos architectures, it could support systems with literally millions of ports, says Bill Woodruff, Velio's VP of marketing.

The key to scaling to such monster sizes is integration, he says. Velio's managed to integrate the functionality of 140 serializer/deserializer (SerDes) chips onto the same piece of silicon as the crosspoint. SerDes are needed to break down high-speed channels into low-speed parallel data streams that silicon can process easily.

Previously, external SerDes devices were required to do this job, which bumps up space and power requirements on the switch card. But equally significant, it multiplies the number of pins needed on the switch chip -- and that becomes a limiting factor on total capacity.

Velio seems confident that it's leading the field with this development. And it has the advantage that its SerDes technology is established -- it's been used in two previous products (see Velio Breaks Grooming Barrier).

But other chip makers are planning to upstage Velio in the coming months, Light Reading has learned. Mindspeed Technologies Inc., for one, expects to start sampling a competing chip in August this year. It will be a 144x144 crosspoint switch with lower power consumption than Velio's chip -- 16W, as opposed to 20W, according to Achim Hill, VP and general manager of Mindspeed's Integrated Circuits for Optical Networking (ICON) group. This will be Mindspeed's first product with integrated SerDes functionality, however.Vitesse Semiconductor Corp. (Nasdaq: VTSS) has already released products with integrated SerDes (see Vitesse's Balancing Act ), but its crosspoint switches don't have the density of Velio's. Right now it's got 36x36 and 68x68 devices, and bigger chips are under development says Rob Sturgill, director of marketing for intelligent switch fabric products at Vitesse. However, he couldn't give a firm date when higher port-count devices might be announced.

He adds that Vitesse's crosspoint switches have another important -- possibly unique -- feature, namely, the ability to power down individual ports. "Substantial power savings can be achieved by powering down individual outputs. It also provides flexibility, because the same part can be used inside smaller chassis with less cooling."

— Pauline Rigby, Senior Editor, Light Reading, http://www.lightreading.com