CWDM's time has come, say supporters. The question is how long will it last?
November 1, 2002 By: Kirk Laughlin America's Network
PAR FOR THE COARSE WDM
Coarse wave division multiplexing is doing for metro networks what McDonald's did for fast food. Cheap, easy-to-install and robust enough to sustain capacity demands for the next few years, CWDM is becoming the quick-fix way for enterprises and, to a lesser extent, carriers to use wavelengths in an increasingly efficient manner.
The CWDM proposition is simple - carry multiple signals on a single fiber pair and forgo the expense of amplification needed with dense WDM because CWDM is designed for the short hop, mainly from the enterprise edge to the service provider core.
It's not just the industry downturn that is triggering interest in CWDM.
A good fit
The ITU's decision in June to define spacing for use of CWDM on the wavelength grid generates plenty of attention from components makers and systems houses, many of whom smell opportunity. "We're on the cusp of moving toward a shared infrastructure where carriers are beginning to focus on managed service wavelength service offerings," says Jack Hunt, Nortel Networks' director of marketing for storage and photonics. He says carriers are increasingly interested in building infrastructure that has a CWDM capability at the edge while hoping to take advantage of a move to create seamless interoperability with DWDM's core. "With that they can manage wavelengths end-to-end. That's what they're looking for."
Although carriers may be anticipating expanded function for optical transport, enterprises are currently the driving force behind CWDM demand. "There are a lot of enterprises looking at this for their own internal networks," says John Mazur, principle optical networking equipment analyst at Gartner Group. "We really don't see a lot of uptake from service providers."
In the case of very large enterprise customers, Hunt points out that many of them have deployed hundreds of wavelengths and will continue to depend on the capacity benefits of DWDM for a primary objective - transport between data centers. "But for a medium-sized they're typically looking for a much lower number of lambdas for their connectivity. That's where CWDM fits nicely," says Hunt.
Part 2 (which mentions LMNE) follows |
