Mike, just a couple of brief points concerning the following:
"The metro-WDM idea is still a little confusing to me in the way it relates to SONET/SDH rings. I'm guessing the marketecture out of the metro-WDM players is for real and WDM can co-exist with SONET/SDH.
WDM simply presents a form of virtual fiber, or wavelength, a.k.a. a lambda. SONET devices regard these wavelengths, more or less, as they would ordinary, physical fibers.
From an layered architecture perspective, most of the SONET protocols that contain intelligence sit on top of the photonic layer. This is true, no matter whether it's a wavelength or a physical fiber.
The photonic section is endemic to SONET, in other words. As such, then the WDM derivatives, too, are endemic to SONET when they are used to support it. So, not only aren't they mutually exclusive, but when viewed in the context I presented above, WDM byproducts (lambdas) are actually a part of the SONET stack.
"In your example I think you are saying, when traffic overload dictates, pull a ring off the SONET network and run DWM over it."
I know what you're getting at, but it would be better stated this way:
When traffic overload dictates, remove the SONET ring from the pair of fibers, and create an 4-lambda WDM ring on those same 2 fibers. You now have, effectively, four virtual rings.
Then go back and reinsert the SONET gear on the first virtual ring. Once the SONET ring has been reinserted, then use the other 3 lambda pairs (a pair consists of a lambda in each direction) for other purposes. Or, create three additional SONET rings over them. |
