[Nml-wg] [Nsi-wg] Conversation about ITU concepts with Ciena folks

[Jeroen van der Ham]

Guy Roberts wrote:
> The other document of note is the transitional link document.  I
> think we need to be careful about adopting this concept since as far
> as I can see it has been created by ITU-T for a very specific
> purpose.  They use it for transit between sub-layers as opposed to
> adaptation between layers.  In their example a transitional link is
> used for all-optical conversion of wavelengths, where wavelengths are
> not real layers as there is no termination and adaptation function 
> when converting between wavelengths.

That's not completely true. As far as I see it there are two kinds of
Transitional Links. The example you are referring to are sub-layer
transitional links, where the connection on a single layer is not
terminated, and readapted, but only the "Characteristic Information" is
transformed, in this case the wavelength.

There is also the Layer Transitional Link. This link does go from a
client layer to a server layer, without specifying all the details. It
seems to be an abstraction of a normal link with an adaptation.

I am not sure whether the distinction between sub-layer and layers is
actually relevant to us. So far I'm inclined to think that it is not
relevant.

Jeroen.