Velio Claims Switch Silicon Breakthrough

Developments that could end up delaying the deployment of all-optical switches are scheduled to be announced next Monday (October 23) by startup Velio Communications Inc.

Velio will unveil a set of chips designed to prolong the life of optical switches with electrical cores. They aim to enable vendors to build much higher capacity switches of this type than was previously possible -- ones that can handle thousands of OC48 (2.5 Gbit/s) and OC192 (10 Gbit/s) ports and hundreds of OC768 (40 Gbit/s) ports. At present Tellium Inc. has the biggest switch of this type, with 512 ports, although Brightlink Networks Inc. is developing an electrical-core switch capable of handling thousands of ports (see Brightlink: My Switch Is Bigger Than Yours). What’s more, Velio's chips promise to eliminate a major problem of this type of switch -- very high power consumption (see Optical Power Trip).

A lot of carriers are likely to heave a sigh of relief at these developments. For a couple of reasons, many of them aren’t keen on moving to all-optical switches to address their needs for higher port counts. First, all-optical switching fabric is at an early stage of development and is a long way from being considered reliable enough to be used in live networks. Second, all-optical switches can only handle whole wavelengths; they don’t deliver the granularity of switches with electrical cores.

Velio says the key to its breakthrough is the integration of input/output (I/O) functions and the switching fabric in the same chip. This results in a pretty meaty integrated circuit. There are about 1.5 million CMOS (complimentary metal oxide semiconductor) gates and about 1000 pins on a package measuring 1.25 inches square.

Velio’s developments appear to run counter to the general trend among developers of switching silicon (see Network Processors Proliferate). “The notion of putting the I/O on the same chip is the way everyone started out. But now folk are moving away from that. Instead they are breaking things out into smaller and smaller pieces that can be assembled,” says Colin Mick from The Mick Group, a consultancy.

“The big problem with putting your I/O processor on the same chip as the switch fabric is that you lose flexibility,” Mick adds. And by the time Velio develops a chip, market requirements may have moved on.

Velio, of course, doesn’t see it this way; and to understand why, it’s necessary to dig into the details of the four types of device it’s developing. They are: