1. Applicability of GMPLS and PCE to Wavelength Switched Optical Networks
draft-bernstein-ccamp-wavelength-switched-00.txt
Greg Bernstein Grotto Networking
Young Lee
Huawei
69th IETF – Chicago, July 2007

2. 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
69th IETF – Chicago, July 2007

3. 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…
69th IETF – Chicago, July 2007

4. Tunable laser transmitters, WDM links
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
69th IETF – Chicago, July 2007

5. 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.
69th IETF – Chicago, July 2007

6. Implications for GMPLS Signaling
Labels  Lambdas (Standard)
Would prefer global meaning to lambda labels to reduce manual configuration and aid interoperability. See T. Otani’s draft.
Wavelength Assignment (Standard)
Using explicit label sub-TLV in the ERO
New optical signals coming “online” (Issue)
Bit rate isn’t sufficient to characterize signal, can add in modulation format as in ITU-T G where modulation format and rate class are defined.
69th IETF – Chicago, July 2007

7. Implications for GMPLS Routing
WDM Link Bandwidth
Need to know what lambdas are available on which links
Representing Wavelength Conversion
Need to know the wavelength conversion capabilities of switching elements
Asymmetrical Switching Elements
See Wataru Imajuku’s draft
69th IETF – Chicago, July 2007

8. 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
Tuning range of source transmitter laser
Link lambda resources
Locations and capabilities of wavelength converters
Switching constraints (see Wataru’s draft)
PCEP enhancements to support additional parameters
RWA capable PCE via PCE Discovery
69th IETF – Chicago, July 2007

9. Summary & Next Steps Summary Next Steps?
Wavelength Switched Optical Networks are maturing technically and commercially to support it GMPLS/PCE needs to be enhanced.
Next Steps?
Within Charter?
Sufficient interest?
Document types
Requirements, Solutions, Applicability statement…
69th IETF – Chicago, July 2007