1. Page - 1 75 th IETF – Stockholm, Sweden, July 2009 WSON Signal Characteristics and Network Element Compatibility Constraints for GMPLS Greg Bernsteingregb@grotto-networking.com Grotto Networkinggregb@grotto-networking.com Young Leeylee@huawei.comylee@huawei.com Huawei Ben Mack-Cranetmackcrane@huawei.com Huawei draft-bernstein-ccamp-wson-signal-00.txt

2. Page - 2 75 th IETF – Stockholm, Sweden, July 2009 WSON Signals and such… Tasks from San Francisco IETF –Generalize WSON element information where appropriate for possibly other technologies. This was incorporated into the WSON RWA info and encoding documents. –Expand the WSON elements understood by the control plane to include regenerators, OEO switches, and wavelength converters. That is what this document addresses.

3. Page - 3 75 th IETF – Stockholm, Sweden, July 2009 Regenerators: Basics 1R –Equal amplification of all frequencies within the amplification bandwidth. There is no restriction upon information formats. –Amplification with different gain for frequencies within the amplification bandwidth. This could be applied to both single- channel and multi-channel systems. –Dispersion compensation (phase distortion). This analogue process can be applied in either single-channel or multi-channel systems. 2R (any or all 1R functions plus:) –Digital reshaping (Schmitt Trigger function) with no clock recovery. This is applicable to individual channels and can be used for different bit rates but is not transparent to line coding (modulation). 3R (any or all 1R and 2R functions plus:) –Complete regeneration of the pulse shape including clock recovery and retiming within required jitter limits. ITU-T Recommendation G.872 Definitions

4. Page - 4 75 th IETF – Stockholm, Sweden, July 2009 Regenerator: Management –Many 3R type regenerators also process important management overhead and hence can be particular to the digital signal format.

5. Page - 5 75 th IETF – Stockholm, Sweden, July 2009 Regenerator Compatibility Constraints Limited wavelength range (1R) –Already modeled in GMPLS for WSON Modulation type restriction (2R) Bit rate range restriction (2R, 3R) Exact bit rate restriction (3R) Client signal dependence (4R) These signal compatibility constraints may also apply to OEO switches and to wavelength converters.

6. Page - 6 75 th IETF – Stockholm, Sweden, July 2009 Optical Interfaces and Signals Optical Tributary Signal (G.959.1) –"a single channel signal that is placed within an optical channel for transport across the optical network" –Different classes of optical tributary signals are defined based on modulation (line coding) and bit rate range. –From G.698.2 to fully specify an optical tributary signal one must specify the exact bit rate. Single channel interfaces to DWDM networks –ITU-T Recommendations G.698.1 & G.698.2 –Uses Optical Tributary Signal from G.959.1.

7. Page - 7 75 th IETF – Stockholm, Sweden, July 2009 Proposed WSON Signal & Parameters Optical Tributary Signal (G.959.1, G.698.1, G.698.2) –Optical tributary signal class: This relates to the specifics of modulation format, and bit rate range. Could possibly change along the path. For example when running through a 3R regenerator a different output modulation format could be used. –Bit rate. This typically would not change since we are not changing the digital bit stream in any end-to-end meaningful way. –FEC: Indicates whether forward error correction is used in the digital stream. –G-PID: General Protocol Identifier for the information format. This would not change since this describes the encoded bit stream. This is already present in GMPLS signaling. A set of G- PID values are already defined for lambda switching in [RFC3471], [RFC4328]. –Center frequency (wavelength). Can change along path if there are wavelength converters. This is already modeled via labels in GMPLS.

8. Page - 8 75 th IETF – Stockholm, Sweden, July 2009 Characterizing Network Elements –Permitted optical tributary signal classes: A list of optical tributary signal classes that can be processed by this network element or carried over this link. –Acceptable Bit Rate Set: A list of specific bit rates or bit rate ranges that the device can accommodate. Coarse bit rate info is included with the optical tributary signal class restrictions. –Acceptable G-PID list: A list of G-PIDs corresponding to the "client" digital streams that are compatible with this device. –Permitted optical frequencies. Already in WSON GMPLS extensions.

9. Page - 9 75 th IETF – Stockholm, Sweden, July 2009 Network Element Compatibility: Digital Format Connection request for an SDH formatted optical connection and computed feasible paths based on network element compatibility. R_AR_B R_C OEO_D GPID=SDH, G709 R_F OEO_G GPID= G.709 R_E Source GPID=SDH

10. Page - 10 75 th IETF – Stockholm, Sweden, July 2009 Client Signal Type Compatibility Two optical subnets interconnected by DWDM links with regenerators. The regenerators for the different DWDM links have differing capabilities to deal with client signal types (G-PID).

11. Page - 11 75 th IETF – Stockholm, Sweden, July 2009 Modulation Compatibility Multi-subnet network where the various subnets work with different sets of signal classes, i.e., the metro subnets work with 10G NRZ and 40G NRZ while the long haul subnet works with 10G NRZ and 40G NRZ. The regenerators on the DWDM links connecting the subnets can be used to perform modulation format conversion between 40G NRZ and 40G RZ signals.

12. Page - 12 75 th IETF – Stockholm, Sweden, July 2009 Path Computation, PCE & Signaling New optical compatibility constraints –Path computation can only choose paths through elements that are compatible with the particulars of the optical tributary signal. PCE requests –Must include optical tributary signal parameters. Signaling –Should include optical tributary signal parameters for configuration and validation.

13. Page - 13 75 th IETF – Stockholm, Sweden, July 2009 Possible Next Steps Add optical tributary signal notions to WSON RWA Framework and related documents Or Keep this work as a separate draft in parallel with WSON RWA Framework