    Internet Engineering Task Force (IETF)                 G. Bernstein, Ed.
    Request for Comments: 7689                             Grotto Networking
    Category: Standards Track                                          S. Xu
    ISSN: 2070-1721                                                     NICT
                                                                 Y. Lee, Ed.
                                                                      Huawei
                                                               G. Martinelli
                                                                       Cisco
                                                                    H. Harai
                                                                        NICT
                                                               November 2015

         Signaling Extensions for Wavelength Switched Optical Networks

    Abstract

       This document provides extensions to Generalized Multiprotocol Label
       Switching (GMPLS) signaling for control of Wavelength Switched
       Optical Networks (WSONs).  Such extensions are applicable in WSONs
       under a number of conditions including: (a) when optional processing,
       such as regeneration, must be configured to occur at specific nodes
       along a path, (b) where equipment must be configured to accept an
       optical signal with specific attributes, or (c) where equipment must
       be configured to output an optical signal with specific attributes.
       This document provides mechanisms to support distributed wavelength
       assignment with a choice of distributed wavelength assignment
       algorithms.

    Status of This Memo

       This is an Internet Standards Track document.

       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).  Further information on
       Internet Standards is available in 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/rfc7689.

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    RFC 7689                WSON Signaling Extensions          November 2015

    Copyright Notice

       Copyright (c) 2015 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 ....................................................3
       2. Terminology .....................................................3
          2.1. Conventions Used in This Document ..........................4
       3. Requirements for WSON Signaling .................................4
          3.1. WSON Signal Characterization ...............................4
          3.2. Per-Node Processing Configuration ..........................5
          3.3. Bidirectional WSON LSPs ....................................5
          3.4. Distributed Wavelength Assignment Selection Method .........6
          3.5. Optical Impairments ........................................6
       4. WSON Signal Traffic Parameters, Attributes, and Processing ......6
          4.1. Traffic Parameters for Optical Tributary Signals ...........7
          4.2. WSON Processing Hop Attribute TLV ..........................7
               4.2.1. ResourceBlockInfo Sub-TLV ...........................8
               4.2.2. WavelengthSelection Sub-TLV .........................9
       5. Security Considerations ........................................11
       6. IANA Considerations ............................................11
       7. References .....................................................13
          7.1. Normative References ......................................13
          7.2. Informative References ....................................14
       Acknowledgments ...................................................15
       Contributors ......................................................15
       Author's Addresses ................................................16

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    RFC 7689                WSON Signaling Extensions          November 2015

    1.  Introduction

       This document provides extensions to Generalized Multiprotocol Label
       Switching (GMPLS) signaling for control of Wavelength Switched
       Optical Networks (WSONs).  Fundamental extensions are given to permit
       simultaneous bidirectional wavelength assignment, while more advanced
       extensions are given to support the networks described in [RFC6163],
       which feature connections requiring configuration of input, output,
       and general signal processing capabilities at a node along a Label
       Switched Path (LSP).

       These extensions build on previous work for the control of lambda and
       G.709-based networks.

       Related documents are [RFC7446] that provides a high-level
       information model and [RFC7581] that provides common encodings that
       can be applicable to other protocol extensions such as routing.

    2.  Terminology

       CWDM: Coarse Wavelength Division Multiplexing.

       DWDM: Dense Wavelength Division Multiplexing.

       ROADM: Reconfigurable Optical Add/Drop Multiplexer.  A reduced port
          count wavelength selective switching element featuring ingress and
          egress line side ports as well as add/drop side ports.

       RWA: Routing and Wavelength Assignment.

       Wavelength Conversion/Converters: The process of converting
          information bearing optical signal centered at a given frequency
          (wavelength) to one with "equivalent" content centered at a
          different wavelength.  Wavelength conversion can be implemented
          via an optical-electronic-optical (OEO) process or via a strictly
          optical process.

       WDM: Wavelength Division Multiplexing.

       Wavelength Switched Optical Networks (WSONs): WDM-based optical
          networks in which switching is performed selectively based on the
          frequency of an optical signal.

       AWG: Arrayed Waveguide Grating.

       OXC: Optical Cross-Connect.

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       Optical Transmitter: A device that has both a laser, tuned on a
          certain wavelength, and electronic components that convert
          electronic signals into optical signals.

       Optical Receiver: A device that has both optical and electronic
          components.  It detects optical signals and converts optical
          signals into electronic signals.

       Optical Transponder: A device that has both an optical transmitter
          and an optical receiver.

       Optical End Node: The end of a wavelength (optical lambdas) lightpath
          in the data plane.  It may be equipped with some
          optical/electronic devices such as wavelength
          multiplexers/demultiplexer (e.g., AWG), optical transponder, etc.,
          which are employed to transmit/terminate the optical signals for
          data transmission.

       FEC: Forward Error Correction.  FEC is a digital signal processing
          technique used to enhance data reliability.  It does this by
          introducing redundant data, called error correcting code, prior to
          data transmission or storage.  FEC provides the receiver with the
          ability to correct errors without a reverse channel to request the
          retransmission of data.

       3R Regeneration: The process of amplifying (correcting loss),
          reshaping (correcting noise and dispersion), retiming
          (synchronizing with the network clock), and retransmitting an
          optical signal.

    2.1.  Conventions Used in This Document

       The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
       "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
       document are to be interpreted as described in [RFC2119].

    3.  Requirements for WSON Signaling

       The following requirements for GMPLS-based WSON signaling are in
       addition to the functionality already provided by existing GMPLS
       signaling mechanisms.

    3.1.  WSON Signal Characterization

       WSON signaling needs to convey sufficient information characterizing
       the signal to allow systems along the path to determine compatibility
       and perform any required local configuration.  Examples of such
       systems include intermediate nodes (ROADMs, OXCs, wavelength

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       converters, regenerators, OEO switches, etc.), links (WDM systems),
       and end systems (detectors, demodulators, etc.).  The details of any
       local configuration processes are outside the scope of this document.

       From [RFC6163], we have the following list of WSON signal
       characteristics:

       1.  Optical tributary signal class (modulation format).
       2.  FEC: whether forward error correction is used in the digital
          stream and what type of error correcting code is used
       3.  Center frequency (wavelength)
       4.  Bit rate
       5.  G-PID: General Protocol Identifier for the information format

       The first three items on this list can change as a WSON signal
       traverses a network with regenerators, OEO switches, or wavelength
       converters.  These parameters are summarized in the Optical Interface
       Class as defined in [RFC7446], and the assumption is that a class
       always includes signal compatibility information.  An ability to
       control wavelength conversion already exists in GMPLS signaling along
       with the ability to share client signal type information (G-PID).  In
       addition, bit rate is a standard GMPLS signaling traffic parameter.
       It is referred to as bandwidth encoding in [RFC3471].

    3.2.  Per-Node Processing Configuration

       In addition to configuring a node along an LSP to input or output a
       signal with specific attributes, we may need to signal the node to
       perform specific processing, such as 3R regeneration, on the signal
       at a particular node.  [RFC6163] discussed three types of processing:

          (A) Regeneration (possibly different types)

          (B) Fault and Performance Monitoring

          (C) Attribute Conversion

       The extensions here provide for the configuration of these types of
       processing at nodes along an LSP.

    3.3.  Bidirectional WSON LSPs

       WSON signaling can support LSP setup consistent with the wavelength
       continuity constraint for bidirectional connections.  The following
       cases need to be supported separately:

       (a)  Where the same wavelength is used for both upstream and
            downstream directions

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       (b)  Where different wavelengths are used for both upstream and
            downstream directions.

       This document will review existing GMPLS bidirectional solutions
       according to WSON case.

    3.4.  Distributed Wavelength Assignment Selection Method

       WSON signaling can support the selection of a specific distributed
       wavelength assignment method.

       This method is beneficial in cases of equipment failure, etc., where
       fast provisioning used in quick recovery is critical to protect
       carriers/users against system loss.  This requires efficient
       signaling that supports distributed wavelength assignment, in
       particular, when the wavelength assignment capability is not
       available.

       As discussed in [RFC6163], different computational approaches for
       wavelength assignment are available.  One method is the use of
       distributed wavelength assignment.  This feature would allow the
       specification of a particular approach when more than one is
       implemented in the systems along the path.

    3.5.  Optical Impairments

       This document does not address signaling information related to
       optical impairments.

    4.  WSON Signal Traffic Parameters, Attributes, and Processing

       As discussed in [RFC6163], single-channel optical signals used in
       WSONs are called "optical tributary signals" and come in a number of
       classes characterized by modulation format and bit rate.  Although
       WSONs are fairly transparent to the signals they carry, to ensure
       compatibility amongst various networks devices and end systems, it
       can be important to include key lightpath characteristics as traffic
       parameters in signaling [RFC6163].

       LSPs signaled through extensions provided in this document MUST apply
       the following signaling parameters:

          o  Switching Capability = WSON-LSC [RFC7688]
          o  Encoding Type = Lambda [RFC3471]
          o  Label Format = as defined in [RFC6205]

       [RFC6205] defines the label format as applicable to LSC capable
       devices.

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    4.1.  Traffic Parameters for Optical Tributary Signals

       In [RFC3471] we see that the G-PID (client signal type) and bit rate
       (byte rate) of the signals are defined as parameters, and in
       [RFC3473] they are conveyed in the Generalized Label Request object
       and the RSVP SENDER_TSPEC/FLOWSPEC objects, respectively.

    4.2.  WSON Processing Hop Attribute TLV

       Section 3.1 provides requirements to signal to a node along an LSP
       what type of processing to perform on an optical signal and how to
       configure itself to accept or transmit an optical signal with
       particular attributes.

       To target a specific node, this section defines a WSON Processing Hop
       Attribute TLV.  This TLV is encoded as an attributes TLV; see
       [RFC5420].  The TLV is carried in the ERO and RRO Hop Attributes
       subobjects and processed according to the procedures defined in
       [RFC7570].  The type value of the WSON Processing Hop Attribute TLV
       is 4 as assigned by IANA.

       The WSON Processing Hop Attribute TLV carries one or more sub-TLVs
       with the following format:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     Type      |   Length      |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
       //                            Value                            //
       |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           ...                 |        Padding                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Type

          The identifier of the sub-TLV.

       Length

          Indicates the total length of the sub-TLV in octets.  That is, the
          combined length of the Type, Length, and Value fields, i.e., two
          plus the length of the Value field in octets.

       Value

          Zero or more octets of data carried in the sub-TLV.

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       Padding

          Variable

       The entire sub-TLV MUST be padded with zeros to ensure four-octet
       alignment of the sub-TLV.

       Sub-TLV ordering is significant and MUST be preserved.  Error
       processing follows [RFC7570].

       The following sub-TLV types are defined in this document:

       Sub-TLV Name        Type    Length
       --------------------------------------------------------------
       ResourceBlockInfo    1      variable
       WavelengthSelection  2      8 octets (2-octet padding)

       The TLV can be represented in Reduced Backus-Naur Form (RBNF)
       [RFC5511] syntax as:

       <WSON Processing Hop Attribute> ::= <ResourceBlockInfo>
       [<ResourceBlockInfo>] [<WavelengthSelection>]

    4.2.1.  ResourceBlockInfo Sub-TLV

       The format of the ResourceBlockInfo sub-TLV value field is defined in
       Section 4 of [RFC7581].  It is a list of available Optical Interface
       Classes and processing capabilities.

       At least one ResourceBlockInfo sub-TLV MUST be present in the WSON
       Processing Hop Attribute TLV.  No more than two ResourceBlockInfo
       sub-TLVs SHOULD be present.  Any present ResourceBlockInfo sub-TLVs
       MUST be processed in the order received, and extra (unprocessed) sub-
       TLVs SHOULD be ignored.

       The ResourceBlockInfo field contains several information elements as
       defined by [RFC7581].  The following rules apply to the sub-TLV:

       o  RB Set field can carry one or more RB Identifier.  Only the first
          RB Identifier listed in the RB Set field SHALL be processed; any
          others SHOULD be ignored.

       o  In the case of unidirectional LSPs, only one ResourceBlockInfo
          sub-TLV SHALL be processed, and the I and O bits can be safely
          ignored.

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       o  In the case of a bidirectional LSP, there MUST be either:

          (a) only one ResourceBlockInfo sub-TLV present in a WSON
              Processing Hop Attribute TLV, and the bits I and O both set to
              1, or

          (b) two ResourceBlockInfo sub-TLVs present, one with only the I
              bit set and the other with only the O bit set.

       o  The rest of the information carried within the ResourceBlockInfo
          sub-TLV includes the Optical Interface Class List, Input Bit Rate
          List, and Processing Capability List.  These lists MAY contain one
          or more elements.  These elements apply equally to both
          bidirectional and unidirectional LSPs.

       Any violation of these rules detected by a transit or egress node
       SHALL be treated as an error and be processed per [RFC7570].

       A ResourceBlockInfo sub-TLV can be constructed by a node and added to
       an ERO Hop Attributes subobject in order to be processed by
       downstream nodes (transit and egress).  As defined in [RFC7570], the
       R bit reflects the LSP_REQUIRED_ATTRIBUTE and LSP_ATTRIBUTE semantic
       defined in [RFC5420], and it SHOULD be set accordingly.

       Once a node properly parses a ResourceBlockInfo sub-TLV received in
       an ERO Hop Attributes subobject (according to the rules stated above
       and in [RFC7570]), the node allocates the indicated resources, e.g.,
       the selected regeneration pool, for the LSP.  In addition, the node
       SHOULD report compliance by adding an RRO Hop Attributes subobject
       with the WSON Processing Hop Attribute TLV (and its sub-TLVs)
       indicating the utilized resources.  ResourceBlockInfo sub-TLVs
       carried in an RRO Hop Attributes subobject are subject to [RFC7570]
       and standard RRO processing; see [RFC3209].

    4.2.2.  WavelengthSelection Sub-TLV

       Routing + Distributed Wavelength Assignment (R+DWA) is one of the
       options defined by [RFC6163].  The output from the routing function
       will be a path, but the wavelength will be selected on a hop-by-hop
       basis.

       As discussed in [RFC6163], the wavelength assignment can be either
       for a unidirectional lightpath or for a bidirectional lightpath
       constrained to use the same lambda in both directions.

       In order to indicate wavelength assignment directionality and
       wavelength assignment method, the WavelengthSelection sub-TLV is
       carried in the WSON Processing Hop Attribute TLV defined above.

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       The WavelengthSelection sub-TLV value field is defined as:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |W|  WA Method  |                    Reserved                   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Where:

       W (1 bit): 0 denotes requiring the same wavelength in both
          directions; 1 denotes that different wavelengths on both
          directions are allowed.

          Wavelength Assignment (WA) Method (7 bits):

          0: unspecified (any); This does not constrain the WA method used
              by a specific node.  This value is implied when the
              WavelengthSelection sub-TLV is absent.

          1: First-Fit.  All the wavelengths are numbered, and this WA
              method chooses the available wavelength with the lowest index.

          2: Random.  This WA method chooses an available wavelength
              randomly.

          3: Least-Loaded (multi-fiber).  This WA method selects the
              wavelength that has the largest residual capacity on the most
              loaded link along the route.  This method is used in multi-
              fiber networks.  If used in single-fiber networks, it is
              equivalent to the First-Fit WA method.

          4-127: Unassigned.

       The processing rules for this TLV are as follows:

       If a receiving node does not support the attribute(s), its behaviors
       are specified below:

       -  W bit not supported: a PathErr MUST be generated with the Error
          Code "Routing Problem" (24) with error sub-code "Unsupported
          WavelengthSelection Symmetry value" (107).

       -  WA method not supported: a PathErr MUST be generated with the
          Error Code "Routing Problem" (24) with error sub-code "Unsupported
          Wavelength Assignment value" (108).

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       A WavelengthSelection sub-TLV can be constructed by a node and added
       to an ERO Hop Attributes subobject in order to be processed by
       downstream nodes (transit and egress).  As defined in [RFC7570], the
       R bit reflects the LSP_REQUIRED_ATTRIBUTE and LSP_ATTRIBUTE semantic
       defined in [RFC5420], and it SHOULD be set accordingly.

       Once a node properly parses the WavelengthSelection sub-TLV received
       in an ERO Hop Attributes subobject, the node use the indicated
       wavelength assignment method (at that hop) for the LSP.  In addition,
       the node SHOULD report compliance by adding an RRO Hop Attributes
       subobject with the WSON Processing Hop Attribute TLV (and its sub-
       TLVs) that indicate the utilized method.  WavelengthSelection sub-
       TLVs carried in an RRO Hop Attributes subobject are subject to
       [RFC7570] and standard RRO processing; see [RFC3209].

    5.  Security Considerations

       This document is built on the mechanisms defined in [RFC3473], and
       only differs in the specific information communicated.  The specific
       additional information (optical resource and wavelength selection
       properties) is not viewed as substantively changing or adding to the
       security considerations of the existing GMPLS signaling protocol
       mechanisms.  See [RFC3473] for details of the supported security
       measures.  Additionally, [RFC5920] provides an overview of security
       vulnerabilities and protection mechanisms for the GMPLS control
       plane.

    6.  IANA Considerations

       IANA has assigned a new value in the existing "Attributes TLV Space"
       registry located at
       <http://www.iana.org/assignments/rsvp-te-parameters>, as updated by
       [RFC7570]:

       Type  Name        Allowed on  Allowed on   Allowed on   Reference
                         LSP         LSP REQUIRED RO LSP
                         ATTRIBUTES  ATTRIBUTES   Attribute
                                                  Subobject

       4     WSON        No          No           Yes          RFC 7689
             Processing
             Hop
             Attribute
             TLV

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       IANA has created a new registry named "Sub-TLV Types for WSON
       Processing Hop Attribute TLV" located at
       <http://www.iana.org/assignments/rsvp-te-parameters>.

       The following entries have been added:

       Value            Sub-TLV Type            Reference

       0                Reserved                RFC 7689

       1                ResourceBlockInfo       RFC 7689

       2                WavelengthSelection     RFC 7689

       All assignments are to be performed via Standards Action or
       Specification Required policies as defined in [RFC5226].

       IANA has created a new registry named "Values for Wavelength
       Assignment Method field in WavelengthSelection Sub-TLV" located at
       <http://www.iana.org/assignments/rsvp-te-parameters>.

       The following entries have been added:

       Value          Meaning                    Reference

       0             unspecified                RFC 7689

       1             First-Fit                  RFC 7689

       2             Random                     RFC 7689

       3             Least-Loaded (multi-fiber) RFC 7689

       4-127         Unassigned

       All assignments are to be performed via Standards Action or
       Specification Required policies as defined in [RFC5226].  The
       assignment policy chosen for any specific code point must be clearly
       stated in the document that describes the code point so that IANA can
       apply the correct policy.

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    RFC 7689                WSON Signaling Extensions          November 2015

       IANA has assigned new values in the existing "Sub-Codes - 24 Routing
       Problem" registry located at
       <http://www.iana.org/assignments/rsvp-parameters>:

       Value              Description                          Reference

       107                Unsupported WavelengthSelection
                          symmetry value                       RFC 7689

       108                Unsupported Wavelength Assignment
                          value                                RFC 7689

    7.  References

    7.1.  Normative References

       [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119,
                  DOI 10.17487/RFC2119, March 1997,
                  <http://www.rfc-editor.org/info/rfc2119>.

       [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
                  and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
                  Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
                  <http://www.rfc-editor.org/info/rfc3209>.

       [RFC3471]  Berger, L., Ed., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Signaling Functional Description", RFC
                  3471, DOI 10.17487/RFC3471, January 2003,
                  <http://www.rfc-editor.org/info/rfc3471>.

       [RFC3473]  Berger, L., Ed., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Signaling Resource ReserVation Protocol-
                  Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
                  DOI 10.17487/RFC3473, January 2003,
                  <http://www.rfc-editor.org/info/rfc3473>.

       [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
                  IANA Considerations Section in RFCs", BCP 26, RFC 5226,
                  DOI 10.17487/RFC5226, May 2008,
                  <http://www.rfc-editor.org/info/rfc5226>.

       [RFC5420]  Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A.
                  Ayyangarps, "Encoding of Attributes for MPLS LSP
                  Establishment Using Resource Reservation Protocol Traffic
                  Engineering (RSVP-TE)", RFC 5420, DOI 10.17487/RFC5420,
                  February 2009, <http://www.rfc-editor.org/info/rfc5420>.

    Bernstein, et al.            Standards Track                   [Page 13]

    RFC 7689                WSON Signaling Extensions          November 2015

       [RFC5511]  Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
                  Used to Form Encoding Rules in Various Routing Protocol
                  Specifications", RFC 5511, DOI 10.17487/RFC5511, April
                  2009, <http://www.rfc-editor.org/info/rfc5511>.

       [RFC6205]  Otani, T., Ed., and D. Li, Ed., "Generalized Labels for
                  Lambda-Switch-Capable (LSC) Label Switching Routers", RFC
                  6205, DOI 10.17487/RFC6205, March 2011,
                  <http://www.rfc-editor.org/info/rfc6205>.

       [RFC7570]  Margaria, C., Ed., Martinelli, G., Balls, S., and B.
                  Wright, "Label Switched Path (LSP) Attribute in the
                  Explicit Route Object (ERO)", RFC 7570,
                  DOI 10.17487/RFC7570, July 2015,
                  <http://www.rfc-editor.org/info/rfc7570>.

       [RFC7581]  Bernstein, G., Ed., Lee, Y., Ed., Li, D., Imajuku, W., and
                  J. Han, "Routing and Wavelength Assignment Information
                  Encoding for Wavelength Switched Optical Networks", RFC
                  7581, DOI 10.17487/RFC7581, June 2015,
                  <http://www.rfc-editor.org/info/rfc7581>.

       [RFC7688]  Lee, Y., Ed., and G. Bernstein, Ed., "GMPLS OSPF
                  Enhancement for Signal and Network Element Compatibility
                  for Wavelength Switched Optical Networks", RFC 7688,
                  DOI 10.17487/RFC7688, November 2015,
                  <http://www.rfc-editor.org/info/rfc7688>.

    7.2. Informative References

       [RFC5920]  Fang, L., Ed., "Security Framework for MPLS and GMPLS
                  Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
                  <http://www.rfc-editor.org/info/rfc5920>.

       [RFC6163]  Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku,
                  "Framework for GMPLS and Path Computation Element (PCE)
                  Control of Wavelength Switched Optical Networks (WSONs)",
                  RFC 6163, DOI 10.17487/RFC6163, April 2011,
                  <http://www.rfc-editor.org/info/rfc6163>.

       [RFC7446]  Lee, Y., Ed., Bernstein, G., Ed., Li, D., and W. Imajuku,
                  "Routing and Wavelength Assignment Information Model for
                  Wavelength Switched Optical Networks", RFC 7446,
                  DOI 10.17487/RFC7446, February 2015,
                  <http://www.rfc-editor.org/info/rfc7446>.

    Bernstein, et al.            Standards Track                   [Page 14]

    RFC 7689                WSON Signaling Extensions          November 2015

    Acknowledgments

       The authors would like to thanks Lou Berger, Cyril Margaria, and Xian
       Zhang for their comments and suggestions.

    Contributors

       Nicola Andriolli
       Scuola Superiore Sant'Anna
       Pisa, Italy
       Email: nick@sssup.it

       Alessio Giorgetti
       Scuola Superiore Sant'Anna
       Pisa, Italy
       Email: a.giorgetti@sssup.it

       Lin Guo
       Key Laboratory of Optical Communication and Lightwave Technologies
       Ministry of Education
       P.O. Box 128, Beijing University of Posts and Telecommunications
       China
       Email: guolintom@gmail.com

       Yuefeng Ji
       Key Laboratory of Optical Communication and Lightwave Technologies
       Ministry of Education
       P.O. Box 128, Beijing University of Posts and Telecommunications
       China
       Email: jyf@bupt.edu.cn

       Daniel King
       Old Dog Consulting
       Email: daniel@olddog.co.uk

    Bernstein, et al.            Standards Track                   [Page 15]

    RFC 7689                WSON Signaling Extensions          November 2015

    Authors' Addresses

       Greg M. Bernstein (editor)
       Grotto Networking
       Fremont, CA
       United States
       Phone: (510) 573-2237
       Email: gregb@grotto-networking.com

       Sugang Xu
       National Institute of Information and Communications Technology
       4-2-1 Nukui-Kitamachi, Koganei,
       Tokyo, 184-8795
       Japan
       Phone: +81 42-327-6927
       Email: xsg@nict.go.jp

       Young Lee (editor)
       Huawei Technologies
       5340 Legacy Dr. Building 3
       Plano, TX  75024
       United States
       Phone: (469) 277-5838
       Email: leeyoung@huawei.com

       Giovanni Martinelli
       Cisco
       Via Philips 12
       20052 Monza
       Italy
       Phone: +39 039-209-2044
       Email: giomarti@cisco.com

       Hiroaki Harai
       National Institute of Information and Communications Technology
       4-2-1 Nukui-Kitamachi, Koganei,
       Tokyo, 184-8795
       Japan
       Phone: +81 42-327-5418
       Email: harai@nict.go.jp

    Bernstein, et al.            Standards Track                   [Page 16]