Page th IETF – Chicago, July 2007 Applicability of GMPLS and PCE to Wavelength Switched Optical Networks Greg Grotto Young Huawei draft-bernstein-ccamp-wavelength-switched-00.txt

Page th IETF – Chicago, July 2007 Motivation This draft addresses the requirements and applicability of GMPLS and PCE to dynamic Wavelength Switched Optical Networks (WSON). Advances in Optical Technology/Practice –Tunable Lasers –Reconfigurable Optical Add/Drop Multiplexers (ROADMs) Maturing Physical Layer Standards –Wavelength Grids (dense and coarse) –WDM interface definitions and signal types

Page th IETF – Chicago, July 2007 Problem/Issue Statement Can current GMPLS/PCE control WDM based systems consisting of tunable laser transmitters and reconfigurable optical add/drop multiplexers (ROADM) or Wavelength Selective Switches (WSS)? Not quite! We address the areas in which GMPLS/PCE protocols need to be enhanced in this draft. –Lambda switching was an original GMPLS motivation…

Page th IETF – Chicago, July 2007 Network Assumptions Tunable laser transmitters, WDM links A variety of wavelength selective switching elements May not always have wavelength conversion capabilities –No wavelength conversion, implies wavelength continuity constraint –Partial wavelength conversion –Full wavelength conversion, e.g., WDM links plus electronic switch fabric

Page th IETF – Chicago, July 2007 Routing and Wavelength Assignment (RWA) Find a path and assign wavelength(s) –No wavelength conversion: Need to find a path such that a single wavelength can be used from source to destination. –Partial wavelength conversion: Need to find a path such that wavelength can only change at points in the network with wavelength converters. –Full wavelength conversion: Only need to find path, wavelengths can be assigned locally between switching elements. Generally a hard problem algorithmically –See, for example: H. Zang, J. Jue and B. Mukherjeee, "A review of routing and wavelength assignment approaches for wavelength-routed optical WDM networks", Optical Networks Magazine, January 2000.

Page th IETF – Chicago, July 2007 Implications for GMPLS Signaling –In good shape some future extensions could be useful. Routing –WDM Link Bandwidth (issue) Need to know what lambdas are available on which links –Representing Wavelength Conversion (issue) Need to know the wavelength conversion capabilities of switching elements –Asymmetrical Switching Elements (issue) See Wataru Imajuku’s draft

Page th IETF – Chicago, July 2007 Implications for PCE RWA is a computationally intensive problem to solve –Well suited to a PCE architecture rather than requiring this computation to be run on all LSC LSRs. PCE needs to know (issue) –Tuning range of source transmitter laser –Link lambda resources –Locations and capabilities of wavelength converters –Switching constraints (see Wataru’s draft)

Page th IETF – Chicago, July 2007 Implications for PCE (cont.) PCE can get required info from: –GMPLS routing if extensions are made –Management System: better if common MIBs for representing switches and wavelength converters are defined and used. Existing MIB RFC3591 can be used to extract link bandwidth information, but not ideal. PCEP enhancements to support additional parameters PCC need to find RWA capable PCE via PCE Discovery

Page th IETF – Chicago, July 2007 Summary & Next Steps Summary –Wavelength Switched Optical Networks are maturing technically and commercially. To support them GMPLS/PCE needs to be enhanced. Next Steps? –Within Charter? –Sufficient interest? –Document types Requirements, Solutions, Applicability statement…