telecommagazine.com
As solutions go, DWDM systems aren't all that flexible. Just as we've seen Class 4 and Class 5 switches broken down into component products in the next-gen voice space, so too has DWDM come to the end of the road in the optical metro market. While immensely popular and valuable, the technology is an expensive proposition for those sites on a network that don't yet require major bandwidth. Yet those same sites may sit on an optical ring that contains nodes demanding more bandwidth. The problem is how to break down a DWDM system so that each site can be upgraded in capacity as demand warrants. Until recently, a service provider was stuck with over-engineering its network to handle future traffic demands and accepting operational cost loss at under-utilized sites. This of course often hampered rollout and increased time to market in critical areas of the country.
Chromatis Networks' solution is to apply a proprietary technology called Selective Wave Division Multiplexing currently running on vendor systems in beta trials. These as-yet unnamed products create two rings on the same fiber: a low-cost single-channel ring at 1310 nm and a multichannel DWDM ring at 1550 nm. Both are managed as a single logical network. This way, all sites can talk over the 1310 nm-shared ring, while the big bandwidth nodes can tap into one or more of the 1550 nm wavelengths. As demand grows, carriers can upgrade any site at any time using the 1550 channels without affecting the service to that site or the rest of the ring. But this is only part of the solution. To top it off, the system supports TDM, ATM and IP so that multiple network elements can use the 1310 shared channel simultaneously and shape that raw capacity into a form that can be used directly by attached network equipment, without service overlays; aggregate multiple lower-speed pipes for more flexible wavelength use; and perform connectivity and restoration in multi-ring, hub and ring/mesh combinations.
The Bottom Line: This technology is a no-brainer provided carrier trials go well. The combination of SWDM and the management capabilities to merge it with existing networks should be a home run, but interoperability is still a concern. Chromatis currently leads a field of one: Are Sycamore and Lucent up to the challenge?
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