1	Information Model for Impaired Optical Path Validation
2	Updates from the last version No major update from the last version Moustafa Kattan was added to co-author
3	Scope of this document Impairments in optical networks can be accounted for in a number of ways as discussed in the Impairment Framework draft . This draft provides an information model for path validation in optical networks utilizing approximate computations. The definitions, characteristics and usage of the optical parameters that form this model are based on ITU-T recommendation G.680 and related. We do not define any new impairment parameters here. This impairment related model is intentionally compatible with the impairment free model of reference [RWA-Info]. Appendix A presents a model for distributed estimation of impairment parameters (R+ distributed WA & IV).
4	Categorization of Impairment Parameters Apply to the network element (NE) as a whole Get one parameter of each particular type in this category per NE Vary on a per port basis Get one parameter of each particular type in this category per NE port. Not all parameters different so smart encoding can save “space”. Vary based on port to port pairs Get one parameter of each particular type in this category per (ingress port, egress port) pair. Not all parameters different so smart encoding can save “space”.
5	Frequency Dependence of Parameters Many optical parameters can exhibit significant variation over frequencies of interest to the network these may include: Channel insertion loss deviation (dB, Max) Channel chromatic dispersion (ps/nm, Max, Min) Channel uniformity (dB, Max) Insertion loss (dB, Max, Min) Channel extinction (dB, Min) Channel signal-spontaneous noise figure (dB, Max) Channel gain (dB, Max, Min) Others TDB in conjunction with ITU-T Q6/15
6	What is not currently covered in this document The end system models (i.e., transmitter and receiver models based on the interfaces defined in G.698.1 and G.698.2) are not included in G.680 but in other ITU documents. Distributed impairment accumulation model attached in appendix (G.680 included Distributed impairment accumulation model only in its appendix)
7	Next Steps and Issues General Issues Should distributed computation model be included here or work on a separate draft when time is mature? Transmitter and Receiver characteristics are not specified in G.680 but in other ITU-T recommendations. Should these be including in info model? Connection request? Issues useful to liaise with ITU-T SG15/Q6 Not all impairments are included in G.680 – Our approach is to begin with what G.680 has defined. Interpolation modeling of frequency dependence?