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To: ITU-T Q12/15, Q14/15, and Q11/15

Thank you for your liaison SG15-LS121: “LS on OCL, Information modelling of MCC and media”. The ONF OIMT & OTCC Projects have progressed on many aspects of the Core Information Model.

With regard to media, the use case of an express channel in a ROADM has led us to consider an additional type of media channel, other than a network media channel. In general, this is a media channel whose frequency slot overlaps with the frequency slots of one or more network media channels, but does not necessarily share their ports. A typical use for this would encompass the spectrum of an integral number of network media channels. G.872 describes media channel concatenation, but does not describe media channels that start and end on two ports of any serial concatenation of media channels. The ROADM “express channel” is an example of this type of media channel which when switched, can effectively switch all network media channels that share its frequency slot. A construct has been discussed in the model for this, and we request that it be considered in and

In G.798 and G.872, the adaptation “OTSi G /<digital OTN client>” is found in various figures. This is understood to mean <this layer CI>/<Client CI> as specified in G.800   and the adaptation source   accepts client layer network characteristic information at its input and processes it to allow transfer over a trail (in the server layer network) ” (G.805). Hence the adaptation label OTSi /<digital OTN client>” implies that an OTSi is the output of a trail termination function. Considering that an OTSi is defined as an optical signal (G.959.1) and that it only emerges from the optical signal modulator/demodulator is not performing trail termination , the nomenclature for the adaptation label does not fit this case. This is caused by a domain change in the media.  it is suggested that the electrical/optical separation be more clearly shown by I i dentifying the electrical signal CI   into the optical signal modulator/demodulator   may be helpful since the modulator/demodulator function is not adding/removing (G.800) Layer Information . This would reserve the “OTSi” label to be used only as the output of the   optical signal modulator/demodulator . Digital OTN clients would then adapt to an electrical CI layer as shown in the following diagram:



It would be useful to have a generic label/name for the electrical signal CI   entering the optical modulator/demodulator.

Terminoloy we found confusing are SOTU and MOTU. As described i n G.798, the y appear below the optical signal modulator/demodulator. As this is an optical signal, it is unclear why they are named using a client name (the “OTU” string). I t would seem that this should be above the optical signal modulator/demodulator. The clarity sought is again related to the separation between electrical and optical , and also to minimize use of client naming for server constructs . In considering the SOTU and MOTU   interface classifications as shown in G. 872 and other Recommendations, we have concluded that th ey do not have to be modeled with other media artifacts. Please advise us if this is not the case .