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WSON Signal Characteristics and Network Element Compatibility Constraints for GMPLS draft-bernstein-ccamp-wson-signal-00.txt Greg Bernstein Young Lee Ben Mack-Crane Page - 1 [email protected] Grotto Networking [email protected] Huawei [email protected] Huawei 75th 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. Page - 2 75th IETF – Stockholm, Sweden, July 2009 Regenerators: Basics • 1R ITU-T Recommendation G.872 Definitions – 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 singlechannel 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. Page - 3 75th IETF – Stockholm, Sweden, July 2009 Regenerator: Management +-----------------------------------------------------------------+ |Function | SONET/SDH | G.709 OTUk | | | Regenerator | | | | Section | | |------------------+----------------------+-----------------------| |Signal | J0 (section | Trail Trace | |Identifier | trace) | Identifier (TTI) | |------------------+----------------------+-----------------------| |Performance | BIP-8 (B1) | BIP-8 (within SM) | |Monitoring | | | |------------------+----------------------+-----------------------| |Management | D1-D3 bytes | GCC0 (general | |Communications | | communications | | | | channel) | |------------------+----------------------+-----------------------| |Fault Management | A1, A2 framing | FAS (frame alignment | | | bytes | signal), BDI(backward| | | | defect indication)BEI| | | | (backward error | | | | indication) | +------------------+----------------------+-----------------------| |Forward Error | P1,Q1 bytes | OTUk FEC | |Correction (FEC) | | | +-----------------------------------------------------------------+ – Many 3R type regenerators also process important management overhead and hence can be particular to the digital signal format. Page - 4 75th 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. Page - 5 75th 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. Page - 6 75th IETF – Stockholm, Sweden, July 2009 Proposed WSON Signal & Parameters • Optical Tributary Signal (G.959.1, G.698.1, G.698.2) – – – – – Page - 7 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 GPID 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. 75th IETF – Stockholm, Sweden, July 2009 Characterizing Network Elements – – – – Page - 8 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. 75th IETF – Stockholm, Sweden, July 2009 Network Element Compatibility: Digital Format Source GPID=SDH R_A R_B OEO_G R_C GPID= G.709 R_F R_E OEO_D GPID=SDH, G709 Connection request for an SDH formatted optical connection and computed feasible paths based on network element compatibility. Page - 9 75th IETF – Stockholm, Sweden, July 2009 Client Signal Type Compatibility Optical Subnet B Regen bank (SDH) Regen bank (SDH, G.709, 10GE) Optical Subnet A 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). Page - 10 75th IETF – Stockholm, Sweden, July 2009 Modulation Compatibility Metro subnets allow optical tributary signal classes: 10G NRZ and 40G NRZ Metro Subnet B Regen bank Regenerators allow optical tributary signal classes: 10G NRZ and 40G NRZ, 40G RZ Long Haul Subnet Regen bank Metro Subnet A Regen bank Long haul subnet allows optical tributary signal classes: 10G NRZ and 40G RZ Metro Subnet C 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. Page - 11 75th 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. Page - 12 75th 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 Page - 13 75th IETF – Stockholm, Sweden, July 2009