2009-03-26, 74 th ietf, san francisco, u.s.a., march 2009 1...

12009-03-26, 74th IETF, San Francisco, U.S.A., March 2009

draft-seno-ccamp-wson-impairment-compensate-cntl-00.txt

Issued March 2nd, 2009

2009-03-26, 74th IETF, San Francisco, U.S.A.

Requirement of Impairment Compensation Control in WSON


Authors and Contributors

Author: Shoichiro Seno, Mitsubishi Electric Corporation E-mail: [email protected] Contributors: Yoshimasa Baba, Eiichi Horiuchi, and Kazuo Kubo, Mitsubishi Electric Corporation


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.


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


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


+-------------+ +-------------+ | 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.



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.



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.


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.


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.


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.


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

2009-03-26, 74 th ietf, san francisco, u.s.a., march 2009 1...

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