PCEP Requirements and Extensions for the support of Wavelength Switched Optical Networks (WSON)

1. PCEP Requirements and Extensions for the support of Wavelength Switched Optical Networks (WSON) Draft-lee-pce-WSON-routing-wavelength-00.txt Young Lee ylee@huawei.com Huawei Greg Bernstein gregb@grotto-networking.com Grotto Networking 70th IETF – Vancouver, December 2007

2. Outline • Applicability of PCE to WSON/RWA • RWA Computation Architecture • Combined RWA • Separate Routing and WA • Routing with Distributed WA • PCEP Requirements • RWA Information Requirement for PCE • Summary 70th IETF – Vancouver, December 2007

3. x x Applicability of PCE-based Architecture for WSON RWA Optical Connection Request OPM+PLC Info Control Plane Connection Controller PCE PCEP Global TED RWA Info Light-path Signaling (GMPLS) • RWA information • Connectivity Information • Per port wavelength restriction • WDM link (fiber) lambda range/ channel spacing • Laser Transmitter range • Wavelength conversion • Wavelength Availability WSON x x 70th IETF – Vancouver, December 2007

4. PCC PCE R+WA PCE WA PCC PCE R RWA Computation Architecture • Combined RWA • Routing and WA are performed at a single computational entity • Separate Routing and WA • Separate entities perform Routing and WA (e.g., one PCE for Routing and one PCE for WA in tandem) • Routing with Distributed WA • Routing is performed at a computation entity (e.g., PCE) while WA via signaling PCE RSVP-TE (Wavelength Set) RSVP-TE (Wavelength Set) NE NE NE 70th IETF – Vancouver, December 2007

5. PCEP Requirements • PCE Computation Options • Wavelength Assignment and Wavelength Set information • Optimization Degree • Lightpath Route Parameters • Wavelength Selection Preference (optional) • Timeliness Characteristics (optional) • Duration of lightpath (optional) 70th IETF – Vancouver, December 2007

6. PCE Computation Options • The following RWA computation options should be conveyed in the PC Request: • The request is for Wavelength Assignment (WA) only. • The request is for both Routing and Wavelength Assignment (R+WA). • The request is for Routing (R) only. • The request is for Routing (R) with the suggested/restricted wavelength set. PC Request {RP object: RC bits} PCC PCE PC Reply {RP object: RC bits} 70th IETF – Vancouver, December 2007

7. Wavelength Assignment and Wavelength Set information • The PCE MUST specify the wavelength assignment and/or wavelength set information in response to the wavelength assignment/wavelength set Request made by the PCC in the PCReq message. • ERO and Exact Assignment: If the original request is either for both Routing and Wavelength Assignment or for Wavelength Assignment only, the exact wavelength assignment result can be conveyed to PCC using the ERO object and ERO Label subobject within the ERO. Note that this is not a new requirement. Current PCEP allows this mechanism which is defined as the Label Set mechanism in [RFC3471]. • Wavelength Set (Inclusive/Exclusive List/Range): If the original request is for Routing with wavelength suggested/restricted wavelength set, then the Wavelength Set information must be provided to the PCC. 70th IETF – Vancouver, December 2007

8. Optimization Degree • The PC Request Message should indicate the degree of optimization associated with lightpath computation. • Concurrent Optimization: multiple lightpaths requested at one time. • Lightpath(s) and backup lightpath(s) requested at one time. • Sequential Optimization: single lightpath requested at a time. The PC Reply Message should include the original optimization degree associated with the request when replying the path computation results. 70th IETF – Vancouver, December 2007

9. Lightpath Route Parameters • The following Lightpath Route Parameters should be indicated: • Bidirectional Assignment of wavelengths for a bidirectional LSP request. • Possible simultaneous assignment of the same wavelength to primary and backup paths. The PC Reply Message should include the original lightpath route parameter associated with the request when replying the path computation results. 70th IETF – Vancouver, December 2007

10. Wavelength SelectionPreference - optional • The PC Request may indicate the Wavelength Selection Preference to which a path computation request is applied. The Wavelength Selection Preference to be supported at the minimum is: • Random • First Fit • Most Used • Least Loaded • Don’t Care The PC Reply should indicate which wavelength selection preference has actually been applied. 70th IETF – Vancouver, December 2007

11. Timeliness Characteristics - optional • The request may indicate specific timeliness characteristics of lightpath. • Time Critical: this type of request is useful for those lightpath establishment requests used for restoration of service or other high priority real time services. • Soft Time Bound: this type of request is a more typical new connection request. While expected to be responsive, there should be more time to take into account network optimization. • Scheduled: this type of request is useful when the requested lightpath connections are not time critical (i.e., the request is significantly ahead of their intended "in-service" time. 70th IETF – Vancouver, December 2007

12. Duration of lightpath - optional • The request may indicate specific lightpath duration information associated with the request. This may be useful to the PCE since it is not worthwhile to optimize lightpaths with relatively short duration as compared to pseudo-static paths. 70th IETF – Vancouver, December 2007

13. Summary • Lightpath provisioning in WSON requires a routing and wavelength assignment (RWA) process which is computationally challenging. • PCE technology is very promising to undertake RWA computation in WSON. • Emerging routing features such as optical impairment constraint-based (ICBR) routing can also be readily built upon this PCE infrastructure. 70th IETF – Vancouver, December 2007

14. Next Steps • Continue to refine PCEP requirements and encoding details • Keep pace with WSON Framework/Info drafts • Explore Methods of RWA Information Transfer Any Questions? 70th IETF – Vancouver, December 2007