Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)
RFC 6163

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Internet Engineering Task Force (IETF)                       Y. Lee, Ed.
Request for Comments: 6163                                        Huawei
Category: Informational                                G. Bernstein, Ed.
ISSN: 2070-1721                                        Grotto Networking
                                                              W. Imajuku
                                                                     NTT
                                                              April 2011

     Framework for GMPLS and Path Computation Element (PCE) Control
            of Wavelength Switched Optical Networks (WSONs)

Abstract

   This document provides a framework for applying Generalized Multi-
   Protocol Label Switching (GMPLS) and the Path Computation Element
   (PCE) architecture to the control of Wavelength Switched Optical
   Networks (WSONs).  In particular, it examines Routing and Wavelength
   Assignment (RWA) of optical paths.

   This document focuses on topological elements and path selection
   constraints that are common across different WSON environments; as
   such, it does not address optical impairments in any depth.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6163.

Lee, et al.                   Informational                     [Page 1]
RFC 6163          Wavelength Switched Optical Networks        April 2011

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................4
   2. Terminology .....................................................5
   3. Wavelength Switched Optical Networks ............................6
      3.1. WDM and CWDM Links .........................................6
      3.2. Optical Transmitters and Receivers .........................8
      3.3. Optical Signals in WSONs ...................................9
           3.3.1. Optical Tributary Signals ..........................10
           3.3.2. WSON Signal Characteristics ........................10
      3.4. ROADMs, OXCs, Splitters, Combiners, and FOADMs ............11
           3.4.1. Reconfigurable Optical Add/Drop
                  Multiplexers and OXCs ..............................11
           3.4.2. Splitters ..........................................14
           3.4.3. Combiners ..........................................15
           3.4.4. Fixed Optical Add/Drop Multiplexers ................15
      3.5. Electro-Optical Systems ...................................16
           3.5.1. Regenerators .......................................16
           3.5.2. OEO Switches .......................................19
      3.6. Wavelength Converters .....................................19
           3.6.1. Wavelength Converter Pool Modeling .................21
      3.7. Characterizing Electro-Optical Network Elements ...........24
           3.7.1. Input Constraints ..................................25
           3.7.2. Output Constraints .................................25
           3.7.3. Processing Capabilities ............................26
   4. Routing and Wavelength Assignment and the Control Plane ........26
      4.1. Architectural Approaches to RWA ...........................27
           4.1.1. Combined RWA (R&WA) ................................27
           4.1.2. Separated R and WA (R+WA) ..........................28
           4.1.3. Routing and Distributed WA (R+DWA) .................28
      4.2. Conveying Information Needed by RWA .......................29

Lee, et al.                   Informational                     [Page 2]
RFC 6163          Wavelength Switched Optical Networks        April 2011

   5. Modeling Examples and Control Plane Use Cases ..................30