Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks (WSON)

1. Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks(WSON) draft-bernstein-ccamp-wavelength-switched-02.txt Greg Bernstein gregb@grotto-networking.com Grotto Networking Young Lee ylee@huawei.com Huawei Wataru Imajuku imajuku.wataru@lab.ntt.co.jp NTT 70th IETF – Vancouver, December 2007

2. Authors/Contributors • Snigdho Bardalai (Fujitsu) • Greg Bernstein (Grotto Networking) • Diego Caviglia (Ericsson) • Wataru Imajuku (NTT) • Daniel King (Aria Networks) • Young Lee (Huawei) • Dan Li (Huawei) • Itaru Nishioka (NEC Corp.) • Lyndon Ong (Ciena) • Jonathan Sadler (Tellabs) 70th IETF – Vancouver, December 2007

3. WSON Framework • Describes wavelength switched optical networks (WSON), subsystems and associated processes. Emphasizing those aspects that are different from other technologies that utilize a GMPLS control plane. • Optical impairments are not currently considered in any depth since different approaches to impairments are used in different WSONs. • Summarize implications to GMPLS routing and signaling, and to PCE protocols. 70th IETF – Vancouver, December 2007

4. WSON Subsystem Models • WDM links • Channel spacing, usable wavelengths, filter constraints • Laser Transmitter/Modulator • Tunability, tuning range, tuning time, (to come “line width”) • Spectral characteristics (modulation type), clock rate, FEC type • ROADMs, FOADMs, and OXCs (oh, my!) • Some of the most popular WSON switching elements are extremely asymmetric. We must have a description of this as an input to path computation. • Wavelength Converters and Regenerators • Technology, ranges, constraints on signal type (1R, 2R, & 3R) 70th IETF – Vancouver, December 2007

5. ROADM Example Ports #3-42 drop • Constraints • Any to Any connectivity is NOT supported! • Example: ingress ports 3-42 (adds) can only egress on port #1 • Various wavelength restrictions can apply to drop ports (colored or colorless, single wavelength or multiple wavelengths) add … … line line 2-Degree ROADM Port #1 Port #2 … … add drop Ports #43-82 70th IETF – Vancouver, December 2007

6. Routing and Wavelength Assignment (RWA) • WSONs with limited or no wavelength converters must perform RWA • Known hard problem (NP complete) • Two basic approaches: combined RWA and two step routing followed by wavelength assignment. • RWA approaches lead to different computational architectures • Combined RWA on a PCE • Routing and WA on separate PCEs • Routing with distributed WA via Signaling 70th IETF – Vancouver, December 2007

7. Implications for GMPLS Signaling • General • Want to be able to describe wavelengths and signals in a unified fashion  Tomohiro’s wavelength label draft is a good start. • Distributed Wavelength Assignment • Takes “pressure” off of routing for bandwidth updates puts it on signaling. • Problem with bi-directional distributed WA  Sugang’s draft proposes a solution. 70th IETF – Vancouver, December 2007

8. Implications for Routing • Different RWA computational Architectures require differing amounts of information via routing • In general all would need ROADM/FOADM/OXC connectivity information • PCE based WA (as opposed to distributed WA via signaling) requires wavelength constraint and availability information 70th IETF – Vancouver, December 2007

9. Next Steps • Adopt WSON-Framework as a Working Group document in order to guide the development of various solution drafts for signaling, routing and PCE applied to WSONs. • Continue to refine as issues are discovered and solutions are finalized. 70th IETF – Vancouver, December 2007