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Information Model for Impaired Optical Path Validation

Information Model for Impaired Optical Path Validation. draft-bernstein-wson-impairment-info-00.txt. Greg Bernstein gregb@grotto-networking.com Grotto Networking Young Lee ylee@huawei.com Huawei Dan Li danli@huawei.com Huawei. Introduction.

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Information Model for Impaired Optical Path Validation

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  1. Information Model for Impaired Optical Path Validation draft-bernstein-wson-impairment-info-00.txt Greg Bernstein gregb@grotto-networking.com Grotto Networking Young Lee ylee@huawei.com Huawei Dan Li danli@huawei.com Huawei 73rd IETF – Minneapolis, MN, November 2008

  2. Introduction • 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. • This impairment related model is intentionally compatible with the impairment free model of reference [RWA-Info]. 73rd IETF – Minneapolis, MN, November 2008

  3. G.680 Calculable Path Quality Measures See section 9 and Appendix II of G.680 • Optical Signal to Noise Ratio (OSNR) • Residual Dispersion (CD) • Polarization Mode Dispersion (PMD) and Polarization Dependent Loss (PDL) • Channel Ripple • System Transients • Channel Uniformity The impact is dependent upon the signal type and rate 73rd IETF – Minneapolis, MN, November 2008

  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”. These categories are inferred from ITU-T G.680 and are useful for control plane purposes and don’t change G.680. 73rd IETF – Minneapolis, MN, November 2008

  5. Port to Port Parameters • Insertion loss (dB, Max, Min) • Isolation, adjacent channel (dB, Min) • Isolation, non-adjacent channel (dB, Min) • Channel extinction (dB, Min) • Channel signal-spontaneous noise figure (dB, Max) • Channel gain (dB, Max, Min) 73rd IETF – Minneapolis, MN, November 2008

  6. Per Port Parameters • Total input power range (dBm, Max, Min) • Channel input power range (dBm, Max, Min) • Channel output power range (dBm, Max, Min) • Input reflectance (dB, Max) (with amplifiers) • Output reflectance (dB, Max) (with amplifiers) • Maximum reflectance tolerable at input (dB, Min) • Maximum reflectance tolerable at output (dB, Min) • Maximum total output power (dBm, Max) 73rd IETF – Minneapolis, MN, November 2008

  7. Per Network Element Parameters • Channel frequency range (GHz, Max, Min) • Channel insertion loss deviation (dB, Max) • Ripple (dB, Max) • Channel chromatic dispersion (ps/nm, Max, Min) • Differential group delay (ps, Max) • Polarization dependent loss (dB, Max) • Reflectance (passive component) (dB, Max) • Reconfigure time/Switching time (ms, Max, Min) • Channel uniformity (dB, Max) • Channel addition/removal (steady-state) gain response (dB, Max, Min) • Transient duration (ms, Max) • Transient gain increase (dB, Max) • Transient gain reduction (dB, Max) • Multichannel gain-change difference (inter-channel gain-change difference) (dB, Max) • Multichannel gain tilt (inter-channel gain-change ratio)(dB, Max) 73rd IETF – Minneapolis, MN, November 2008

  8. Example Usage of Parameters • Cascade formulas given in sections 9 and 10 of G.680 • Example Optical SNR: • Where to Pin,i are the channel powers in dBm at the inputs to the ONEs or amplifiers on the relevant path through the network; and NFi are the noise factors of the amplifiers or ONEs on the relevant path through the network. 73rd IETF – Minneapolis, MN, November 2008

  9. Issues • Not all parameters are necessarily used in all situations. Should default values be explicitly specified in draft? • 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? • Not all impairments are included in G.680 – Our approach is to begin with what G.680 has defined. • Compact Encodings are possible when per port or port-to-port parameters repeat. Define encodings here or another document? • 32-bit floating point for all parameters for simplicity? 73rd IETF – Minneapolis, MN, November 2008

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