1. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 1 draft-seno-ccamp-wson-impairment-compensate-cntl-00.txt Issued March 2 nd, 2009 2009-03-26, 74 th IETF, San Francisco, U.S.A. Requirement of Impairment Compensation Control in WSON

2. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 2 Authors and Contributors Author: Shoichiro Seno, Mitsubishi Electric Corporation E-mail: Senoo.Shoichiro@dc.MitsubishiElectric.co.jp Contributors: Yoshimasa Baba, Eiichi Horiuchi, and Kazuo Kubo, Mitsubishi Electric Corporation

3. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 3 Scope of This Document WSON with impairments: -Enables selection of an appropriate route and wavelength for a requested optical path with consideration of optical impairments by the IA-RWA process. -Will specify the means to convey optical impairments in the Control Plane, including estimated values of them. -Does not include definition, terminology, and measurement of optical impairments. WSON may be enhanced by: -Impairment compensation control for tunable compensation devices. -Automatic discovery of fiber-related link impairments. This document explains the reasons behind them.

4. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 4 Impairment Compensation Impairment Compensation is essential for optical transmission: Example: Compensation of chromatic dispersion -Transmitter node: Transmitter-side compensator, DCF; -Transient node: 3R repeater, DCF -Receiver node: Receiver-side compensator, DCF. Tunable compensation devices: -Can adjust themselves corresponding to a dynamic optical path’s impairments. -Requires control mechanism for adjustment. DCF: Dispersion Compensation Fiber

5. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 5 The IA-RWA process of WSON will estimate a route and wavelength pair’s impairments for Impairment Validation (IV).  Also beneficial for compensation control, i.e., (i) Selection of impairment compensation devices Assignment of compensation devices with different capabilities based on the estimates will maximize their usage. (ii) Initial setting of impairment compensation parameters Path establishment time will be shortened by configuring compensation devices using the estimates. (iii) Optimization of impairment compensation parameters Further optimization of compensation devices may be achieved by measuring performance of sample signal sent over the path selected by IA-RWA. Impairment Compensation Control

6. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 6 +-------------+ +-------------+ | Transmitter | | Receiver | +-------------+ +-------------+ | (A) measurement agreement | | | | (B) sample signal | | =====================================> | | | | (C) measurement result | | <------------------------------------- | | | -----> : Control Plane messages =====> : Data Plane sample signal Figure 1 A Typical Measurement Process Impairment Compensation Control (Continued) For optimization of impairment compensation parameters, the Control Plane can support control sequence of performance measurement of sample signal.

7. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 7 Impairment Compensation Control (Continued) Generic Impairment Compensation Control Procedure: (1) Path establishment request (2) Selection of the path’s route and wavelength with an estimate of Impairments (IA-RWA process) (3) Assignment of compensation devices with initial setting of compensation parameters. (4) Optimization of compensation parameters through measurement of performance and adjustment of the compensation devices.

8. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 8 Impairment Compensation Control (Continued) Requirements of Impairments Compensation Control: (a) Transmission of an estimate of impairments of a path from the IA-RWA entity to nodes. (b) Transmission of an estimate of accumulated impairments between nodes. (c) Transmission of compensation device selection information, and optionally, compensation device setting parameters, from the IA-RWA entity to nodes. (d) Transmission of compensation device selection information, and optionally, compensation device setting parameters, between nodes. (e) Transmission of measurement control information between sample signal's transmitter and receiver.

9. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 9 Link Impairment Discovery Automatic discovery of link impairments upon installation of an optical node or an optical link may be beneficial for automated input of impairments to the IA-RWA entity. - Signaling-based impairment collection is not applicable at installation. - Link impairment discovery based on the same procedure as Neighbor Discovery can automate input of link impairments for the IA-RWA process.

10. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 10 Link Impairment Discovery (Continued) Link impairment discovery in the IA-RWA architectures: (i) Centralized IA-RWA Notification of discovered impairments by each node to PCE. (ii) Distributed IA-RWA (ii-1) Routing-based collection Advertisement of discovered impairments by each node for sharing. (ii-2) Signaling-based collection Use of discovered impairments by Impairment collection signaling.

11. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 11 Link Impairment Discovery (Continued) Requirements of Link Impairment Discovery (a)Transmission of link impairment measurement control information between a link's terminating nodes. (b)Transmission of measurement results from the receiver to the transmitter.

12. 2009-03-26, 74 th IETF, San Francisco, U.S.A., March 2009 12 1. Inclusion of impairment compensation control and link impairment discovery in the WSON framework. 2. GMPLS protocol extensions for impairment compensation control and link impairment discovery, with appropriate characterization of them by guidance of ITU-T. Next Step