Signaling Extensions for Wavelength Switched Optical Networks

draft-bernstein-ccamp-wson-signaling-02.txt

Greg Bernstein Grotto NetworkingYoung Lee HuaweiSugang Xu NICTHiroaki Harai NICT

Daniel KingDaniel King Old Dog ConsultingOld Dog Consulting

WSON Work Items• Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks

draft-bernstein-ccamp-wavelength-switched-03.txt • Signaling Extensions for Wavelength Switched Optical Networks

draft-bernstein-ccamp-wson-signaling-02.txt• Routing and Wavelength Assignment Information Model for Wavelength Switched

Optical Networks draft-bernstein-ccamp-wson-info-03.txt

• PCEP Requirements and Extensions for WSON Routing and Wavelength Assignment draft-lee-pce-wson-routing-wavelength-02.txt

Relevant to WSON Signal Extensions• Generalized Labels for G.694 Lambda-Switching Capable Label Switching Routers

draft-ietf-ccamp-gmpls-g-694-lambda-labels-02.txt• Routing and Wavelength Assignment Information Encoding for Wavelength

Switched Optical Networks draft-bernstein-ccamp-wson-encode-00.txt

WSON Signaling Extensions

• Provide extensions to Generalized Multi-Protocol Label Switching (GMPLS) signaling for control of Wavelength Switched Optical Networks (WSON).

Changes from 01:• Separated requirements section from solution sections.• Created detailed appendix on bi-directional requirements

with same wavelength.• Combined draft Xu since last revision and added three

new authors: Sugang Xu, Hiroaki Harai & Daniel King.

WSON Signaling Requirements

• Two key requirements identified for WSON signaling:

– WSON Signal CharacterizationAbility to determine path compatibility and request specific optical parameters and resources.

– Bi-Directional Distributed Wavelength AssignmentPermit simultaneous bi-directional wavelength assignment.

• Optional feature to be decided upon:

– Distributed Wavelength Assignment Method SelectionSelection of optimal wavelength assignment algorithm.

Requirement 1

• Problem: WSON Signal CharacterizationWSON signaling would convey the necessary information to allow systems along the path to determine path compatibility and perform any required nodal configuration.

• Solution: Lightpath characteristics are defined as traffic parameters. Defines a signal type field that consists of modulation format/rate information. Similar to method used for SONET/SDH signals (RFC4606) and G.709 signals (RFC4328).

Requirement 2

• Problem: Bi-Directional Distributed Wavelength AssignmentTo reduce setup and recovery times there needs to be support for distributed wavelength assignment consistent with the wavelength continuity constraint for bi-directional connections. Current GMPLS approach to bi-directional signaling does not work with distributed wavelength assignment.

• Solution: Incorporation of Draft Xu Defines a mechanism for same wavelength bidirectional lightpath. Reduces setup times and lowers blocking probability.

Bidirectional Blocking Probabilities• Simulations of a Pan-European network with 27 nodes, 55 WDM links with 32 channels per link

• “Label Set” method is that proposed in the draft, “Upstream label” selects “best guess” bi-directional wavelength (label) based on aggregate information (label set mechanisms cannot be used).

•See: N. Andriolli, A. Giorgetti, S. Ruepp, J. Buron, L.Valcarenghi, P. Castoldi, "Bidirectional Lightpath Provisioning in GMPLS-Controlled Optical Networks", To Appear International Conference on Photonics in Switching, August 2008.

Optional Feature

• Problem: Distributed Wavelength Assignment Method SelectionA variety wavelength assignment algorithms are available. These are discussed in the WSON Framework draft.

• Solution: Wavelength Assignment Method SelectionWavelength assignment can be either for a unidirectional lightpath or for a bidirectional lightpath constrained to use the same lambda in both directions. A TLV could be used to indication wavelength assignment directionality and wavelength assignment method.

Next Steps

• Additional Work:– Decide on keeping RWA selection feature.– Need to document bidirectional lightpath using different

wavelengths on different directions. – Work to finalize signal characterization.

• Look for other requirements, further review and feedback.

• Advance implementations.

• Adopt as a WG ID.