CCAMP Working Group                                         Fatai Zhang
Internet-Draft                                               Xian Zhang
Intended status: Standards Track                                 Huawei
                                                          Adrian Farrel
                                                     Old Dog Consulting
                                                 Oscar Gonzalez de Dios
                                                          D. Ceccarelli
Expires: May 19, 2016                                 November 20, 2015

   RSVP-TE Signaling Extensions in support of Flexi-grid DWDM networks



   This memo describes the extensions to the Resource reSerVation
   Protocol Traffic Engineering (RSVP-TE) signaling protocol to support
   Label Switched Paths (LSPs) in a GMPLS-controlled network that
   includes devices using the flexible optical grid.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with
   the provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   reference material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at

   The list of Internet-Draft Shadow Directories can be accessed at

   This Internet-Draft will expire on May 19, 2016.

   Copyright Notice

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   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
   ( in effect on the date of
   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with
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   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 ................................................ 2
   2. Terminology ................................................. 3
      2.1. Conventions used in this document .......................3
   3. Requirements for Flexible Grid Signaling .....................3
      3.1. Slot Width ............................................. 4
      3.2. Frequency Slot ......................................... 4
   4. Protocol Extensions ......................................... 5
      4.1. Traffic Parameters...................................... 5
         4.1.1. Applicability to Fixed Grid Networks ...............6
      4.2. Generalized Label....................................... 6
      4.3. Signaling Procedures.................................... 7
   5. IANA Considerations ......................................... 7
      5.1. RSVP Objects Class Types................................ 7
   6. Manageability Considerations................................. 8
   7. Implementation Status........................................ 8
      7.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)8
   8. Acknowledgments ............................................ 10
   9. Security Considerations..................................... 10
   10. References ................................................ 10
      10.1. Normative References.................................. 10
      10.2. Informative References................................ 10
   11. Contributors' Addresses.................................... 11
   12. Authors' Addresses .........................................12

1. Introduction

   [G.694.1] defines the Dense Wavelength Division Multiplexing (DWDM)
   frequency grids for Wavelength Division Multiplexing (WDM)
   applications. A frequency grid is a reference set of frequencies
   used to denote allowed nominal central frequencies that may be used

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   for defining applications that utilize WDM transmission. The channel
   spacing is the frequency spacing between two allowed nominal central
   frequencies. All of the wavelengths on a fiber use different central
   frequencies and occupy a designated range of frequency.

   Fixed grid channel spacing is selected from 12.5 GHz, 25 GHz, 50 GHz,
   100 GHz and integer multiples of 100 GHz. But [G.694.1] also defines
   "flexible grids", known as "flexi-grid". The terms "frequency slot"
   (i.e., the frequency range allocated to a specific channel and
   unavailable to other channels within a flexible grid) and "slot
   width" (i.e., the full width of a frequency slot in a flexible grid)
   are introduced in [G.694.1] to define a flexible grid.

   [FLEX-FWK] defines a framework and the associated control plane
   requirements for the Generalized Multi-Protocol Label Switching
   (GMPLS) [RFC3945] based control of flexi-grid DWDM networks.

   [RFC6163] provides a framework for GMPLS and Path Computation
   Element (PCE) control of Wavelength Switched Optical Networks
   (WSONs), and [WSON-SIG] describes the requirements and protocol
   extensions for signaling to set up Label Switched Paths (LSPs) in

   This document describes the additional requirements and protocol
   extensions to Resource reSerVation Protocol-Traffic Engineering
   (RSVP-TE) [RFC3473] to set up LSPs in networks that support the

2. Terminology

   For terminology related to flexi-grid, please refer to [FLEX-FWK]
   and [G.694.1].

2.1. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC-2119 [RFC2119].

3. Requirements for Flexible Grid Signaling

   The architecture for establishing LSPs in a flexi-grid network is
   described in [FLEX-FWK].

   An optical spectrum LSP occupies a specific frequency slot, i.e., a
   range of frequencies. The process of computing a route and the
   allocation of a frequency slot is referred to as Routing and

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   Spectrum Assignment (RSA). [FLEX-FWK] describes three architectural
   approaches to RSA: combined RSA, separated RSA, and distributed SA.
   The first two approaches are referred to as "centralized SA" because
   both routing and spectrum (frequency slot) assignment are performed
   by a centralized entity before the signaling procedure.

   In the case of centralized SA, the assigned frequency slot is
   specified in the RSVP-TE Path message during LSP setup. In the case
   of distributed SA, the slot width of the flexi-grid LSP is specified
   in the Path message, allowing the network elements to select the
   frequency slot to be used when they process the RSVP-TE messages.

   If the capability to switch or convert the whole optical spectrum
   allocated to an optical spectrum LSP is not available at some nodes
   along the path of the LSP, the LSP is subject to the Optical
   "Spectrum Continuity Constraint" as described in [FLEX-FWK].

   The remainder of this section states the additional requirements for
   signaling in a flexi-grid network.

3.1. Slot Width

   The slot width is an end-to-end parameter representing how much
   frequency resource is requested for a flexi-grid LSP. It is the
   equivalent of optical bandwidth, although the amount of bandwidth
   associated with a slot width will depend on the signal encoding.

   Different LSPs may request different amounts of frequency resource
   in flexible grid networks, so the slot width MUST be carried in the
   signaling message during LSP establishment. This enables the nodes
   along the LSP to know how much frequency resource has been requested
   (in a Path message) and has been allocated (by a Resv message) for
   the LSP.

3.2. Frequency Slot

   The frequency slot information identifies which part of the
   frequency spectrum is allocated on each link for an LSP in a flexi-
   grid network.

   This information MUST be present in a Resv message to indicate, hop-
   by-hop, the central frequency of the allocated resource. In
   combination with the slot width indicated in a Resv message (see
   Section 3.1) the central frequency carried in a Resv message
   identifies the resources reserved for the LSP (known as the
   frequency slot).

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   The frequency slot can be represented by the two parameters as

      Frequency slot = [(central frequency) - (slot width)/2] ~
                       [(central frequency) + (slot width)/2]

   As is common with other resource identifiers (i.e., labels) in GMPLS
   signaling, it must be possible for the head-end node when sending a
   Path message to suggest or require the central frequency to be used
   for the LSP. Furthermore, for bidirectional LSPs, the Path message
   MUST be able to specify the central frequency to be used for reverse
   direction traffic.

   As described in [G.694.1], the allowed frequency slots for the
   flexible DWDM grid have a nominal central frequency (in THz) defined

   193.1 + n * 0.00625

   where n is zero or a positive or negative integer.

   The slot width (in GHz) is defined as:

   12.5 * m

   where m is a positive integer.

   It is possible that an implementation supports only a subset of the
   possible slot widths and central frequencies. For example, an
   implementation could be built where the nominal central frequency
   granularity is 12.5 GHz (by only allowing values of n that are even)
   and that only supports slot widths as a multiple of 25 GHz (by only
   allowing values of m that are even).

   Further details can be found in [FLEX-FWK].

4. Protocol Extensions

   This section defines the extensions to RSVP-TE signaling for GMPLS
   [RFC3473] to support flexible grid networks.

4.1. Traffic Parameters

   In RSVP-TE, the SENDER_TSPEC object in the Path message indicates
   the requested resource reservation. The FLOWSPEC object in the Resv
   message indicates the actual resource reservation.

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   As described in Section 3.1, the slot width represents how much
   frequency resource is requested for a flexi-grid LSP. That is, it
   describes the end-to-end traffic profile of the LSP. Therefore, the
   traffic parameters for a flexi-grid LSP encode the slot width.

   This document defines new C-Types for the SENDER_TSPEC and FLOWSPEC
   objects to carry Spectrum Switched Optical Network (SSON) traffic

   SSON SENDER_TSPEC: Class = 12, C-Type = TBD1.

   SSON FLOWSPEC: Class = 9, C-Type = TBD2.

   The SSON traffic parameters carried in both objects MUST have the
   same format as shown in Figure 1.

    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
   |              m                |            Reserved           |

                   Figure 1: The SSON Traffic Parameters

   m (16 bits): a positive integer and the slot width is specified by
   m*12.5 GHz.

   The Reserved bits MUST be set to zero and ignored upon receipt.

4.1.1. Applicability to Fixed Grid Networks

   Note that the slot width (i.e., traffic parameters) of a fixed grid
   defined in [G.694.1] can also be specified by using the SSON traffic
   parameters. The fixed grid channel spacings (12.5 GHz, 25 GHz, 50
   GHz, 100 GHz and integer multiples of 100 GHz) are also the
   multiples of 12.5 GHz, so the m parameter can be used to represent
   these slot widths.

   Therefore, it is possible to consider using the new traffic
   parameter object types in common signaling messages for flexi-grid
   and legacy DWDM networks.

4.2. Generalized Label

   In the case of a flexible grid network, the labels that have been
   requested or allocated as signaled in the RSVP-TE objects are

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   encoded as described in [FLEX-LBL]. This new label encoding can
   appear in any RSVP-TE object or sub-object that can carry a label.

   As noted in Section 4.2 of [FLEX-LBL], the m parameter forms part of
   the label as well as part of the traffic parameters.

   As described in Section 4.3 of [FLEX-LBL], a "compound label",
   constructed from a concatenation of the flexi-grid LABELs, is used
   when signaling an LSP that uses multiple flexi-grid slots.

4.3. Signaling Procedures

   There are no differences between the signaling procedure described
   for LSP control in [FLEX-FWK] and those required for use in a fixed-
   grid network [WSON-SIG]. Obviously, the TSpec, FlowSpec, and label
   formats described in Sections 4.1 and 4.2 are used. The signaling
   procedures for distributed SA and centralized SA can be applied.

5. IANA Considerations

5.1. RSVP Objects Class Types

   This document introduces two new Class Types for existing RSVP
   objects. IANA is requested to make allocations from the "Resource
   ReSerVation Protocol (RSVP) Parameters" registry using the "Class
   Names, Class Numbers, and Class Types" sub-registry.

       Class Number  Class Name                            Reference
       ------------  -----------------------               ---------
       9             FLOWSPEC                              [RFC2205]

                     Class Type (C-Type):

                     (TBD2) SSON FLOWSPEC                  [This.I-D]

       Class Number  Class Name                            Reference
       ------------  -----------------------               ---------
       12            SENDER_TSPEC                          [RFC2205]

                     Class Type (C-Type):

                     (TBD1) SSON SENDER_TSPEC              [This.I-D]

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   IANA is requested to assign the same value for TBD1 and TBD2, and a
   value of 8 is suggested.

6. Manageability Considerations

   This document makes minor modifications to GMPLS signaling, but does
   not change the manageability considerations for such networks.
   Clearly, protocol analysis tools and other diagnostic aids
   (including logging systems and MIB modules) will need to be enhanced
   to support the new traffic parameters and label formats.

7. Implementation Status

   [RFC Editor Note: Please remove this entire seciton prior to
   publication as an RFC.]

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of
   this Internet-Draft, and is based on a proposal described in RFC
   6982 [RFC6982].  The description of implementations in this section
   is intended to assist the IETF in its decision processes in
   progressing drafts to RFCs.  Please note that the listing of any
   individual implementation here does not imply endorsement by the
   IETF.  Furthermore, no effort has been spent to verify the
   information presented here that was supplied by IETF contributors.
   This is not intended as, and must not be construed to be, a catalog
   of available implementations or their features.  Readers are advised
   to note that other implementations may exist.

   According to RFC 6982, "this will allow reviewers and working groups
   to assign due consideration to documents that have the benefit of
   running code, which may serve as evidence of valuable
   experimentation and feedback that have made the implemented
   protocols more mature.  It is up to the individual working groups to
   use this information as they see fit."

7.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

   Organization Responsible for the Implementation:
      Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)
      Optical Networks and Systems Department

   Implementation Name and Details:
      ADRENALINE testbed

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   Brief Description:
      Experimental testbed implementation of GMPLS/PCE control plane.

   Level of Maturity:
      Implemented as extensions to a mature GMLPS/PCE control plane.
      It is limited to research / prototyping stages, but it has been
      used successfully for more than the last five years.

      Support for the Tspec, FlowSpec, and label formats as described
      version 03 of this document.  Label format support extends to the
      following RSVP-TE objects and sub-objects:

         - Generalized Label Object
         - Suggested Label Object
         - Upstream Label Object
         - ERO Label Subobjects

      It is expected that this implementation will evolve to follow the
      evolution of this document.


   Implementation Experience:
      Implementation of this document reports no issues.
      General implementation experience has been reported in a number
      of journal papers. Contact Ramon Casellas for more information or

   Contact Information:
      Ramon Casellas:

      No report.

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8. Acknowledgments

   This work was supported in part by the FP-7 IDEALIST project under
   grant agreement number 317999.

9. Security Considerations

   This document introduces no new security considerations to [RFC3473].

   See also [RFC5920] for a discussion of security considerations for
   GMPLS signaling.

10. References

10.1. Normative References

   [RFC2119] S. Bradner, "Key words for use in RFCs to indicate
             requirements levels", RFC 2119, March 1997.

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

   [G.694.1] ITU-T Recommendation G.694.1 (revision 2), "Spectral grids
             for WDM applications: DWDM frequency grid", February 2012.

   [FLEX-LBL] King, D., Farrel, A. and Y. Li, "Generalized Labels for
             the Flexi-Grid in Lambda Switched Capable (LSC) Label
             Switching Routers", draft-ietf-ccamp-flexigrid-lambda-
             label, work in progress.

10.2. Informative References

   [RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching
             (GMPLS)" Architecture, RFC3945, October 2004.

   [RFC2205] Braden, R., Zhang L., Berson, S., Herzog, S. and S. Jamin,
             "Resource ReServation Protocol (RSVP) - Version 1,
             Functional Specification", RFC2205, September 1997.

   [RFC5920] L. Fang et al., "Security Framework for MPLS and GMPLS
             Networks", RFC 5920, July 2010.

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   [RFC6163] Y. Lee, G. Bernstein and W. Imajuku, "Framework for GMPLS
             and Path Computation Element (PCE) Control of Wavelength
             Switched Optical Networks (WSONs)", RFC 6163, April 2011.

   [RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
             Code: The Implementation Status Section", RFC 6982, July

   [RFC Editor Note: This reference can be removed when Section 7 is

   [FLEX-FWK] Gonzalez de Dios, O, Casellas R., Zhang, F., Fu, X.,
             Ceccarelli, D., and I. Hussain, "Framework and
             Requirements for GMPLS based control of Flexi-grid DWDM
             networks", draft-ietf-ccamp-flexi-grid-fwk, work in

   [WSON-SIG] G. Bernstein, Sugang Xu, Y. Lee, G. Martinelli and
             Hiroaki Harai, "Signaling Extensions for Wavelength
             Switched Optical Networks", draft-ietf-ccamp-wson-
             signaling, work in progress.

11. Contributors' Addresses

   Ramon Casellas
   Av. Carl Friedrich Gauss n7
   Castelldefels, Barcelona 08860


   Felipe Jimenez Arribas
   Telefonica Investigacion y Desarrollo
   Emilio Vargas 6
   Madrid,   28045

   Yi Lin
   Huawei Technologies Co., Ltd.
   F3-5-B R&D Center, Huawei Base,
   Bantian, Longgang District
   Shenzhen 518129 P.R.China

   Phone: +86-755-28972914

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   Qilei Wang

   Haomian Zheng
   Huawei Technologies

12. Authors' Addresses

   Fatai Zhang
   Huawei Technologies

   Xian Zhang
   Huawei Technologies

   Adrian Farrel
   Old Dog Consulting

   Oscar Gonzalez de Dios
   Telefonica Investigacion y Desarrollo
   Emilio Vargas 6
   Madrid,   28045
   Phone: +34 913374013

   Daniele Ceccarelli
   Via A. Negrone 1/A
   Genova - Sestri Ponente

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