Network Working Group                                      G. Bernstein
Internet Draft                                        Grotto Networking
Intended status: Standards Track                              Sugang Xu
Expires: January September 2014                                           Y.Lee
                                                          G. Martinelli
                                                          Hiroaki Harai


                                                          March 5, 2013 2014

     Signaling Extensions for Wavelength Switched Optical Networks


   This memo provides extensions to Generalized Multi-Protocol Label
   Switching (GMPLS) signaling for control of wavelength switched
   optical networks (WSON).  Such extensions are necessary 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. In addition this memo provides mechanisms to
   support distributed wavelength assignment with bidirectional LSPs,
   and choice in distributed
   wavelength assignment algorithms. These extensions build on previous
   work for the control of lambda and G.709 based networks. This
   document updates [RFC6205] as make it applicable to WSON-LSC capable

Status of this Memo

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   the provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

Table of Contents

   1. Introduction...................................................3
   2. Terminology....................................................3
   3. Requirements for WSON Signaling................................4
      3.1. WSON Signal Characterization..............................4
      3.2. Per LSP Network Element Processing Configuration..........5
      3.3. Bi-Directional Bidirectional WSON LSPs..................................5 LSPs...................................6
      3.4. Distributed Wavelength Assignment Selection Method........6
      3.5. Out of Scope..............................................6 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 Object Encoding...........................7 HOP Attribute TLV Encoding................7
      4.3. Signal Attributes and Processing Capabilities.............8
      4.4. Wavelength Assignment Method Selection....................8 Selection TLV Encoding.......9

   5. Bidirectional Lightpath Setup.................................10
   6. Security Considerations.......................................10
   6. IANA Considerations...........................................11
   8. Considerations...........................................10
   7. Acknowledgments...............................................11
   8. References....................................................12
      8.1. Normative References.....................................12
      8.2. Informative References...................................13
   Author's Addresses...............................................15
   Intellectual Property Statement..................................16
   Disclaimer of Validity...........................................17

1. Introduction

   This memo provides extensions to Generalized Multi-Protocol Label
   Switching (GMPLS) signaling for control of wavelength switched
   optical networks (WSON).  Fundamental extensions are given to permit
   simultaneous bi-directional 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 LSP.

   These extensions build on previous work for the control of lambda
   and G.709 based networks. networks [RFC3471].

   Related references with this document are [WSON-info] that provides
   a high-level information model and and [WSON-Encode] 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.

   FOADM: Fixed Optical Add/Drop Multiplexer.

   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 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 (WSON): WDM based optical
   networks in which switching is performed selectively based on the
   center wavelength of an optical signal.

   AWG: Arrayed Waveguide Grating.

   OXC: Optical Cross Connect.

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

   Optical Responder: 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 responder.

   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.

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 MUST 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
   converters, Regenerators, OEO Switches, etc...), links (WDM systems)
   and end systems (detectors, demodulators, etc...). The details of
   any local configuration processes are out of the scope of this

   From [RFC6163] we have the following list of WSON signal
   characteristic information:

                    List 1. 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 the [WSON-Info] 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 LSP Network Element Processing Configuration

   In addition to configuring a network element (NE) along an LSP to
   input or output a signal with specific attributes, we may need to
   signal the NE to perform specific processing, such as 3R
   regeneration, on the signal at a particular NE.  In [RFC6163] we
   discussed three types of processing not currently covered by GMPLS:

     (A) Regeneration (possibly different types)

     (B) Fault and Performance Monitoring

     (C) Attribute Conversion

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

3.3. Bi-Directional Bidirectional WSON LSPs

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

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

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

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

3.4. Distributed Wavelength Assignment Selection Method

   WSON signaling MAY 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 which supports distributed wavelength assignment, in
   particular when the centralized wavelength assignment capability is
   not available.

   As discussed in the [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. Out of Scope Optical Impairments

   This draft does not address signaling information related to optical

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:

     . Switching Capability = WSON-LSC ([WSON-OSPF]).
     . Encoding Type = Lambda ([RFC3471])
     . Label Format = as defined in [RFC6205]

   [RFC6205] defines the label format as applicable to LSC capable
   device. This document extend [RFC6205] as make its label format
   applicable also to WSON-LSC capable devices.

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 Generalized Label Request object and the
   RSVP SENDER_TSPEC/FLOWSPEC objects respectively.

4.2. WSON Processing Object HOP Attribute TLV Encoding

   Section 3.2. provided the requirements for signaling to indicate to
   a particular NE along an LSP what type of processing to perform on
   an optical signal or how to configure that NE to accept or transmit
   an optical signal with particular attributes.

   To target a specific node, this section defines a WSON_Processing
   object as part of the LSP_REQUIRED_ATTRIBUTE and follows procedures
   defined in [RSVP-RO].

   The content of this object TLV is defined in the subsequent sections. (See
   Section 4.3 for <RBInformation> TLV and Section 4.4 for
   <WavelengthSelection> TLV, respectively.)


   <WSON_Processing HOP Attribute> ::= <RBInformation>

   The WSON Processing object encoding 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
   |            Type               |             Length            |
   |                                                               |
   ~                            Value                              ~
   |                                                               |

   Type: to be carries sub-TLVs of the same format as a HOP
   Attributes TLV, as defined by IANA

   Value: sub-TLVS according to section 4.3 and 4.4 in [RSVP-RO].

4.3. Signal Attributes and Processing Capabilities

   The [WSON-Encode] already provides all necessary definitions and
   encoding for WSON information required for signaling. In particular,
   the Resource block information sub-TLV contains, among others, a
   list of available Optical Interface Classes and processing

   <RBInformation> is defined in Section 4.1 of [WSON-Encode].

     Type        Sub-TLV

   1 (TBA)      <RBInformation>

   At least one <RBInformation> sub-TLV MUST always be present in the
   WSON_Processing Object otherwise a PathErr SHALL be generated. HOP Attribute TLV.. At most two <RBInformation> sub-TLVs sub-
   TLVs MAY be present in the WSON_Processing Object. HOP Attribute TLV . If
   more than two objects are encountered, two MUST be processed and the
   rest SHOULD be ignored.

   The <RBInformation> contains several information as defined by
   [WSON-Encode]. The following processing rules apply:

   RB Set Field MAY contain more than one RB Indetifier. Only the first
   one MUST be processed, the others SHOULD be ignored.

   The I an E flags MUST be set according to bidirectional LSP
   signaling and the numbers of RBInformation subobjects available. In
   case of unidirectional signaling, only one RBInformartion sub-object
   MUST be processed and  I/E bits can be safely ignored. In case of
   bidirectional signaling: if only one RBInformartion is available,
   bits I and E MUST be both set to 1, if two RBInformation sub-objects
   are available, bits I and E MUST have different values.

   The rest of information available within RBInformation sub-object is
   Optical Interface Class List, Input Bit Range List and Processing
   Capability List. Lists MAY contain one or more elements. The usage
   of WSON Processing object for the bidirectional case is the same as
   per unidirectional. When an intermediate node uses information from
   this object to instruct a node about wavelength regeneration, the
   same information applies to both downstream and upstream directions.

4.4. Wavelength Assignment Method Selection TLV Encoding

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

   Under this hypothesis the node initiating the signaling process
   needs to declare its own wavelength availability (through a
   label_set object). Each intermediate node may delete some labels due
   to connectivity constraints or its own assignment policy. At the
   end, the destination node has to make the final decision on the
   wavelength assignment among the ones received through the signaling

   As discussed in [HZang00] a number of different wavelength
   assignment algorithms maybe employed. In addition 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.

   A simple sub-TLV could be used to indication wavelength assignment
   directionality and wavelength assignment method. method as a TLV in the LSP
   Attributes Object, as defined in [RFC5420].

      Type               Sub-TLV


       TDB          <WavelengthSelection>

       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                   |


     . W is a bit, 0 same wavelength in both directions, 1 may use
        different wavelengths
     . Wavelength Assignment (WA) Method: 0 unspecified (any), 1
        First-Fit, 2 Random, 3 Least-Loaded (multi-fiber).  Others TBD.

5. Security Considerations

   This sub-TLV MAY be present in the WSON_Processing Object. If more
   than one sub-TLV document is encountered the first one MUST be processed, the
   rest SHOULD be ignored.

5. Bidirectional Lightpath Setup

   With the wavelength continuity constraint in CI-incapable [RFC3471]
   WSONs, where the nodes in the networks cannot support wavelength
   conversion, the same wavelength builds on each link along a unidirectional
   lightpath should be reserved. In addition to the wavelength
   continuity constraint, requirement 3.3 gives us another constraint
   on wavelength usage in data plane, in particular, it requires the
   same wavelength to be used in both directions. [RFC6163] in section
   6.1 reports on the implication to GMPLS signaling related to both
   bi-directionality and Distributed Wavelengths Assignment.

   Current GMPLS solution defines a bidirectional LSP (as mechanisms defined by
   [RFC3471]). The label distribution is based on Label_Set and
   Upstream_Label objects. In case of specific constraints such as the
   same wavelengths in both directions, it may require several
   signaling attempts using information from the Acceptable_Label_Set
   received from path error messages. Since this mechanism is currently
   available  [RFC3473], and proven to work, no additional extensions are needed
   for WSON. Potential optimizations are left for further studies.

   The usage of WSON Processing object for the bidirectional case is
   the same as per unidirectional. When an intermediate node uses
   information from this object to instruct a node about wavelength
   regeneration, the same
   only differs in specific information applies to both downstream and
   upstream directions.

   Some implementations may prefer using two unidirectional LSPs. This
   solution has been always available as per [RFC3209] however recent
   work introduces the association concept [RFC4872] and [ASSOC-Info].
   Recent transport evolutions [ASSOC-ext] provide a way to associate
   two unidirectional LSPs as a bidirectional LSP. In line with this, a
   small extension can make communicated. As such, this approach work for the WSON case.

6. Security Considerations

   document has introduces no requirement for a change new security considerations to the security models
   within existing
   GMPLS and associated signaling protocols. That is the OSPF-TE, RSVP-TE,
   and PCEP security models could be operated unchanged.

   However satisfying the requirements See [RFC3473], for RWA using the existing
   protocols may significantly affect the loading of those protocols.
   This makes the operation details of the network more vulnerable to denial
   supported security measures. Additionally, [RFC5920] provides an
   overview of
   service attacks. Therefore additional care maybe required to ensure
   that the protocols are secure in the WSON environment.

   Furthermore the additional information distributed in order to
   address security vulnerabilities and protection mechanisms for
   the RWA problem represents a disclosure GMPLS control plane.

6. IANA Considerations

   Upon approval of network
   capabilities that an operator may wish to keep private.
   Consideration should be given to securing this information.

7. document, IANA Considerations will make the following
   assignments as follows:

   A new LSP_REQUIRED_ATTRIBUTE type is required


   Value             Sub-TLV                             Reference

   3 (Suggested)     WSON Processing Object (Section 4.2)

   Two types of HOP Attribute TLV   [This ID]

   One new type sub-TLV are is allowed within the WSON Processing LSP_Attributes Object

   Value             Sub-TLV

     1 (Proposed)          WSON Processing Capabilities (Section 4.3)

     2 (Proposed)          WSON                             Reference

   4 (Suggested)     Wavelength Assignments (Section 4.4)

8. Selection                [This ID]

7. Acknowledgments

   Authors would like to thanks Lou Berger and Cyril Margaria for
   comments and suggestions.


8. References


8.1. Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
             "Structure of Management Information Version 2 (SMIv2)",
             STD 58, RFC 2578, April 1999.

   [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
             and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
             Tunnels", RFC 3209, December 2001.

   [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
             (GMPLS) Signaling Functional Description", RFC 3471,
             January 2003.

   [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
             Switching (GMPLS) Signaling Resource ReserVation Protocol-
             Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
             January 2003.

   [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
             in Resource ReSerVation Protocol - Traffic Engineering
             (RSVP-TE)", RFC 3477, January 2003.

   [RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, J.-P., and A.
             Ayyangar, " Encoding of Attributes for MPLS LSP
             Establishment Using Resource Reservation Protocol Traffic
             Engineering (RSVP-TE)", RFC 5420, February 2006.

   [RFC5920] Luyuan Fang(Ed.), "Security Framework for MPLS and GMPLS
             Networks", RFC5920, July 2010. [WSON-Encode]   Bernstein
             G., Lee Y., Li D., and W. Imajuku, "Routing and Wavelength
             Assignment Information Encoding for Wavelength Switched
             Optical Networks", draft-ietf-ccamp-
             rwa-wson-encode-20 (work draft-ietf-ccamp-rwa-wson-encode, work
             in progress). progress.

   [RFC6205] T. Otani, H. Guo, K. Miyazaki, D. Caviglia, "Generalized
             Labels for G.694 Lambda-Switching Capable Label Switching
             Routers", RFC 6205, March 2011.

   [RSVP-RO] Margaria, C., et al, "LSP Attribute in ERO", draft-ietf-
             ccamp-lsp-attribute-ro (work
             ccamp-lsp-attribute-ro,work in progress).

9.2. progress.

8.2. Informative References

   [WSON-CompOSPF] Y. Lee, G. Bernstein, "OSPF Enhancement for Signal
             and Network Element Compatibility for Wavelength Switched
             Optical Networks", work in progress: draft-lee-ccamp-wson-

   [RFC6163]  Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS
             and PCE Control of Wavelength Switched Optical Networks",
             work in progress: draft-bernstein-ccamp-wavelength-
             switched-03.txt, February 2008.

   [WSON-Info] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and
             Wavelength Assignment Information Model for Wavelength
             Switched Optical Networks", work in progress: draft-ietf-
             ccamp-rwa-info, work in progress.

   [HZang00] H. Zang, J. Jue and B. Mukherjeee, "A review of routing
             and wavelength assignment approaches for wavelength-routed
             optical WDM networks", Optical Networks Magazine, January

   [Xu]     S. Xu, H. Harai, and D. King, "Extensions to GMPLS RSVP-TE
             for Bidirectional Lightpath the Same Wavelength", work in
             progress: draft-xu-rsvpte-bidir-wave-01, November 2007.

   [Winzer06]    Peter J. Winzer and Rene-Jean Essiambre, "Advanced
             Optical Modulation Formats", Proceedings of the IEEE, vol.
             94, no. 5, pp. 952-985, May 2006.

   [G.959.1] ITU-T Recommendation G.959.1, Optical Transport Network
             Physical Layer Interfaces, March 2006.

   [G.694.1] ITU-T Recommendation G.694.1, Spectral grids for WDM
             applications: DWDM frequency grid, June 2002.

   [G.694.2] ITU-T Recommendation G.694.2, Spectral grids for WDM
             applications: CWDM wavelength grid, December 2003.

   [G.Sup43] ITU-T Series G Supplement 43, Transport of IEEE 10G base-R
             in optical transport networks (OTN), November 2006.

   [RFC4427] Mannie, E., Ed., and D. Papadimitriou, Ed., "Recovery
             (Protection and Restoration) Terminology for Generalized
             Multi-Protocol Label Switching (GMPLS)", RFC 4427, March

   [RFC4872] Lang, J., Rekhter, Y., and Papadimitriou, D., "RSVP-TE
             Extensions in Support of End-to-End Generalized Multi-
             Protocol Label Switching (GMPLS) Recovery", RFC 4872,

   [ASSOC-Info] Berger, L., Faucheur, F., and A. Narayanan, "Usage of
             The RSVP Association Object", draft-ietf-ccamp-assoc-info-
             00 (work in progress), October 2010.

   [ASSOC-Ext] Zhang, F., Jing, R., "RSVP-TE Extension to Establish
             Associated Bidirectional LSP", draft-zhang-mpls-tp-rsvp-
             te-ext-associated-lsp-03 (work in progress), February

Author's Addresses

   Greg M. Bernstein (editor)
   Grotto Networking
   Fremont California, USA

   Phone: (510) 573-2237

   Nicola Andriolli
   Scuola Superiore Sant'Anna, Pisa, Italy

   Alessio Giorgetti
   Scuola Superiore Sant'Anna, Pisa, Italy

   Lin Guo
   Key Laboratory of Optical Communication and Lightwave Technologies
   Ministry of Education
   P.O. Box 128, Beijing University of Posts and Telecommunications,

   Hiroaki Harai
   National Institute of Information and Communications Technology
   4-2-1 Nukui-Kitamachi, Koganei,
   Tokyo, 184-8795 Japan

   Phone: +81 42-327-5418

   Yuefeng Ji
   Key Laboratory of Optical Communication and Lightwave Technologies
   Ministry of Education
   P.O. Box 128, Beijing University of Posts and Telecommunications,

   Daniel King
   Old Dog Consulting


   Young Lee (editor)
   Huawei Technologies
   5360 Legacy Dr. Building 3
   Plano, TX 75024

   Phone: (469) 277-5838

   Sugang Xu
   National Institute of Information and Communications Technology
   4-2-1 Nukui-Kitamachi, Koganei,
   Tokyo, 184-8795 Japan

   Phone: +81 42-327-6927

   Giovanni Martinelli
   Via Philips 12
   20052 Monza, IT

   Phone: +39 039-209-2044

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