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CCAMP Working Group                                   Richard Douville
Internet Draft                                   Dimitri Papadimitriou
                                                       Emmanuel Dotaro
Expires: August 2003                                           Alcatel

                                                         Rauf Izmailov
                                                    Aleksandar Kolarov
                                                                   NEC

                                                            John Drake
                                                               Calient

                                                         February 2003



    Extensions to Generalized MPLS in support of Waveband Switching

         draft-douville-ccamp-gmpls-waveband-extensions-03.txt



Status of this Memo

   This document is an Internet-Draft and is in full conformance with
      all provisions of Section 10 of RFC2026 [1].

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that
   other groups may also distribute working documents as Internet-
   Drafts. Internet-Drafts are draft documents valid for a maximum of
   six months and may be updated, replaced, or obsoleted by other
   documents at any time. It is inappropriate to use Internet- Drafts
   as reference material or to cite them other than as "work in
   progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

1. Abstract

   Generalized MPLS (GMPLS) extends the MPLS control plane to encompass
   layer 2, time-division, wavelength and spatial switching. A
   functional description of the extensions to MPLS signaling needed to
   support the new types of switching is provided in [RFC-3471]. On the
   other hand, along with the current development on IP over optical
   switching, considerable advances in optical transport systems based
   on the multiple optical switching granularities have been developed.

   [RFC-3471] currently defines two layers of optical granularity using
   wavelengths and fibers. By introducing an extended definition of

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   waveband switching, this document specifies the corresponding GMPLS
   extensions, to further integrate optical multi-granularity and
   benefit from the features of the corresponding switching layers.

2. Summary for Sub-IP Area

2.1. Summary

   See the Abstract above.

2.2. Where does it fit in the Picture of the Sub-IP Work

   This work fits the CCAMP box.

2.3. Why is it Targeted at this WG

   This draft is targeted at the CCAMP WG, because it specifies the
   extensions to the GMPLS signaling. GMPLS is itself addressed in the
   CCAMP WG.

2.4. Justification of Work

   The WG should consider this document as it specifies the extensions
   to the GMPLS signaling. These extensions are related to the
   definition of waveband switching and the introduction of optical
   multi-granularity.

3. 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 RFC-2119 [2].

   Other abbreviations and terminology in addition to the [GMPLS-ARCH],
   [RFC-3471] and [GMPLS-RTG] are:

      WB LSP    =       WaveBand LSP
      WBSC      =       WaveBand Switching Capable
      WXC       =       Wavelength Cross-Connect
      WBXC      =       WaveBand Cross-Connect
      FXC       =       Fiber Cross-Connect
      OXC       =       Optical Cross Connect
      PXC       =       Photonic Cross Connect

4. Introduction

   The optical multi-granularity concept relies on technologies working
   at the different switching levels (e.g. wavelength, waveband and
   fiber). In the context of this memo, the granularities considered
   inside optical networks are single wavelengths (Lambda LSP), bundles
   of wavelengths referred to as wavebands (WB LSP), and whole fibers
   (Fiber LSP). One of the key benefits of multi-granularity is to
   simplify the switching procedures of multiple lower order LSPs

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   (Lambda LSPs, for instance) by switching these LSPs as a single
   entity at a higher order (e.g. WB LSP or Fiber LSP). To enable such
   grouping of LSPs, several grooming policies can be defined (either
   end-to-end or intermediate). Details concerning these policies are
   out of the scope of the present document.

   For this purpose, this memo extends the current set of GMPLS
   switching capabilities in the optical domain (see [RFC-3471]) by
   taking into account optical components working at the waveband
   level. Within the set of optical multi-granularity capabilities,
   three approaches to waveband switching have been identified 1)
   Inverse Multiplexing 2) Wavelength Concatenation and 3) Waveband
   Multiplexing/De-multiplexing.

   The common availability of optical/photonic switching equipment
   capable to work at the band level motivates the redefinition of
   waveband switching as defined in the GMPLS architecture. Current
   definition of waveband switching (see [GMPLS-ARCH] and [RFC-3471])
   refers to inverse multiplexing mechanism or wavelength concatenation
   ("contiguous" lambdas in a trunk defining a logical waveband at the
   control plane level). While this definition is still valid and
   applicable, it does not consider the approach where wavebands have a
   physical significance, i.e. where the interface is WaveBand-Switch
   Capable (WBSC). Physical waveband has the ability to switch directly
   a portion of the frequency spectrum without the need to distinguish
   between its inner components (e.g. wavelengths or even below in
   certain known cases), this by using waveband (de)/multiplexing
   components.

   The following document groups the extensions to the GMPLS protocol
   suite required to provide optical multi-granularity (distributed)
   control and particularly the extensions required for waveband
   switching support.

5. Extensions to the GMPLS Architecture and Protocol Suite

5.1. Architecture

   The integration of optical multi-granularity in the GMPLS
   architecture requires some extensions to the definitions it
   currently includes.

   The [GMPLS-ARCH] document considers waveband switching a particular
   case of lambda switching. As specified, a waveband represents a set
   of contiguous wavelengths, which can be switched together. This
   definition of waveband is too restrictive at least on two key
   aspects:

   - The first one is that current definition of waveband implies a
   wavelength composition of the waveband, due to waveband switching by
   wavelength cross-connects (WXC). This definition provides support to
   inverse multiplexing mechanism and wavelength concatenation. This
   approach limits the use of waveband to the wavelength switch capable

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   technologies. With waveband switching technologies, the interface
   does not distinguish between the component optical channels, sub-
   channels (i.e. timeslots) or packets on the waveband which is switch
   as a single unit (wide frequency spectrum) like it could be done
   with the fibers (the penultimate frequency spectrum) on photonic
   cross-connect (PXC).

   - The second restrictive point is that the current definition of the
   waveband does not allow for intermediate grooming.

   For this purpose, this memo introduces an additional optical
   granularity representing the waveband. This definition is quite
   general and backward compatible, it allows requesting a set of
   contiguous wavelengths (i.e. inverse multiplexing mechanism and
   wavelength concatenation) but also address the "real" waveband
   switching and the corresponding set of capabilities. Therefore, the
   proposed definition better fits into the whole GMPLS control plane
   architecture.

   Correspondingly, this memo specifies a new type of interface
   switching capable interface: the Waveband-Switch Capable Interface
   (WBSC). The WBSC interface materializes the physical reality of
   optical waveband in the form of an atomic entity or granularity. As
   with the introduction of the waveband switching capable interface, a
   new class of LSP is defined: the WaveBand LSP (WB LSP).

   The below figure illustrates the hierarchy of the (optical)
   switching layers and highlights the optical multi-granularity part.
   The switching element column shows typical (piece of) equipment that
   can be part of the same node and thus simultaneously support such
   interfaces.

     LSP Hierarchy        Interfaces         Switching Element
     -------------        ----------         -----------------

     Lambda LSP (1) <--->    LSC     <---->       WXC    -
                                                          |
       WB LSP (1)   <--->    WBSC    <---->       WBXC     > Optical MG
                                                          |
       Fiber LSP    <--->    FSC     <---->       FXC    -

   (1) WB LSPs can be supported on both Lambda and WaveBand Switch
   Capable interfaces depending on the nature of the waveband being
   requested (inverse multiplexing, wavelength concatenation, and
   physical waveband).

   Note that this representation does not aim at restricting interfaces
   that network elements can support.

5.2 GMPLS Signalling

5.2.1 Generalized Label Request


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   To support Waveband LSP request, the values of the LSP Encoding
   Type, the Switching Type and the Generalized PID (G-PID) fields
   included in the Generalized Label Request, are extended.

   The information carried in a Generalized Label Request is:

     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | LSP Enc. Type |Switching Type |             G-PID             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   LSP Encoding Type: 8 bits

        Indicates the encoding of the LSP being requested. The
        following Value 14 and Type Waveband (Photonic) is added to the
        existing LSP Encoding Type values to provide Waveband LSP
        support:

             Value              Type
             -----              ----
                 1              Packet
                 2              Ethernet
                 3              ANSI/ETSI PDH
                 4              Reserved
                 5              SDH ITU-T G.707 / SONET ANSI T1.105
                 6              Reserved
                 7              Digital Wrapper
                 8              Lambda (photonic)
                 9              Fiber
                10              Reserved
                11              FiberChannel
                12              G.709 ODUk (Digital Path)
                13              G.709 Optical Channel
                14             Waveband (Photonic)

        For example, consider an LSP signaled with "WaveBand" encoding.
        It is expected that such an LSP would be supported with no
        electrical conversion and no knowledge of the frequency
        cutting, modulation and speed by the transit nodes. Other
        formats normally require framing knowledge, and field
        parameters are broken into the framing type and speed.

   Switching Type: 8 bits

        Indicates the type of switching that should be performed on a
        particular link. This field is needed for links that advertise
        more than one type of switching capability. For OXC or PXC
        enabling Waveband switching, the WBSC value is used to refer to
        such switching capability. Other values of this field are as
        the Switching Capability field defined in [GMPLS-RTG]

   Generalized PID (G-PID): 16 bits

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        An identifier of the payload carried by an LSP, i.e. an
        identifier of the client layer of that LSP.  This is used by
        the nodes at the endpoints of the LSP, and in some cases by the
        penultimate hop. Standard Ethertype values are used for packet
        and Ethernet LSPs; other values are defined in [RFC-3471].

        A waveband can carry a Lambda LSP while a Waveband LSP can be
        transported on a Fiber LSP, the following additional G-PID
        values must be considered: see [RFC-3471] section 3.1.1 û
        Required Information, paragraph on Generalized-PID

           Value        Type               Technology
           -----        ----               ----------
            58          Waveband           Fiber

        In addition the following existing values must be updated in
        order to reflect the transport of Ethernet and SDH/SONET
        payload over a waveband LSP:

            33          Ethernet           SDH, Lambda, Waveband, Fiber
            34          SDH                Lambda, Waveband, Fiber
            35          Reserved           None
            36          Digital Wrapper    Lambda, Waveband, Fiber
            37          Lambda             Waveband, Fiber

5.2.2 Generalized Label

   In the present context, the waveband label space can make use of the
   wavelength label format (see [RFC-3471]) where each waveband is
   uniquely identified, on a per node basis, by a Waveband Id (used as
   label).

   It is also assumed that a list of tuples of the form [Waveband Id,
   <Local Wavelength Id, Remote Wavelength Id>, <..,..>] is maintained
   on a local basis. Association between local and remote Waveband Id's
   can be performed either manually (by configuration) or using [LMP].
   Local mapping between <Local Wavelength Id, Remote Wavelength Id>
   and Waveband Id can be performed either manually (by configuration)
   or using [LMP].

5.3. GMPLS Routing

5.3.1 Waveband Interface Switching Capability

   A new WaveBand-Switch Capability (WBSC) value shall be defined to
   identify and distinguish the associated switching capability of a
   link [MPLS-HIER]. If the switching capability of a (TE) link is of
   type WBSC, it means that the node receiving data over this link
   (fiber) can recognize and switch individual WaveBands on this link
   (without distinguishing lambdas, channels or packets).



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   Values defined in [GMPLS-RTG] and the one defined in the present
   context gives the following Interface Switching Capabilities list:

                 Packet-Switch Capable-1 (PSC-1)
                 Packet-Switch Capable-2 (PSC-2)
                 Packet-Switch Capable-3 (PSC-3)
                 Packet-Switch Capable-4 (PSC-4)
                 Layer-2 Switch Capable  (L2SC)
                 Time-Division-Multiplex Capable (TDM)
                 Lambda-Switch Capable   (LSC)
                 Waveband-Switch Capable (WBSC)
                 Fiber-Switch Capable    (FSC)

   Note that the node that is advertising a given link (i.e., the node
   that is transmitting) has to know the switching capabilities at the
   other end of the link (i.e., the receiving end of the link). One way
   to accomplish this is through configuration. Other options to
   accomplish this are outside the scope of this document.

   In brief, if an interface is of type WBSC, it means that the node
   receiving data over this interface can recognize and switch
   wavebands (sets of contiguous lambdas) within the interface as a
   unit (without distinguishing lambdas, sub-channels or packets). On
   the other hand, an interface that allows for waveband switching
   belongs (at least) to the WBSC type.

5.3.2. Interface Switching Capability Descriptor

   The Interface Switching Capability Descriptor is defined in [GMPLS-
   RTG] and format specified for OSPF and ISIS in [GMPLS-OSPF] and
   [GMPLS-ISIS], respectively.

   - For ISIS, the Interface Switching Capability Descriptor is a sub-
   TLV (of type 21) of the extended IS reachability TLV. The length is
   the length of value field in octets.

   - For OSPF, the Interface Switching Capability Descriptor is a sub-
   TLV of the Link TLV with type 15. The length is the length of value
   field in octets.

   A new value for the Switching Capability (Switching Cap) field is
   defined here to identify Waveband-Switch Capable (WBSC) interfaces:

        151   Waveband Switching Capable   (WBSC)

   In the Interface Switching Capability Descriptor (ISCD), when the
   Switching Capability (Switching Cap) field contains the value for
   WBSC, the technology specific information field includes the Minimum
   LSP Bandwidth, which is defined as the minimum number of contiguous
   wavelength constituting a WaveBand entity. The Maximum LSP is simply
   defined as the maximum number of contiguous wavelength that can
   constitute a WaveBand entity. Additional technology specific
   information MAY also be considered such as the channel spacing.

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   It is expected here that the corresponding properties (for instance,
   the number of wavelength supported per wavebands or wavelength
   spacing) to be grouped and a dedicated Resource Class/Color to be
   assigned to each of these groups allowing for a more efficient path
   computation (using pruning).

5.4. LSP Regions and Forwarding Adjacencies

   The information carried in the Switching Capability field (8 bits)
   of the Interface Switching Capability Descriptor (ISCD) is used to
   construct LSP regions, and determine regions' boundaries as defined
   in [MPLS-HIER].

   The introduction of the new WBSC Interface Switching Capability
   define a new ordering among the switching capabilities: PSC-1 < PSC-
   2 < PSC-3 < PSC-4 < L2SC < TDM < LSC < WBSC < FSC.

   Path computation may take into account this WBSC region boundary
   when computing a path for a LSP. When an LSP need to cross a region
   boundary, it can trigger the establishment of a Forwarding Adjacency
   LSP (FA-LSP) at the underlying layer. For instance, when a Lambda
   LSP or a L2SC LSP needs to cross a WBSC region, it can trigger the
   establishment of a Waveband FA-LSP or re-use an existing one if a
   matching is found.

6. Security Considerations

   No additional security considerations beyond the one covered in
   RSVP-TE (see [RFC-3209]) and CR-LDP (see [RFC-3212]).

7. References

7.1 Normative References

   [GMPLS-ARCH] E.Mannie (Editor) et al., "Generalized Multi-Protocol
                Label Switching (GMPLS) Architecture", Internet Draft,
                Work in progress, draft-ietf-ccamp-gmpls-architecture-
                03.txt, August 2002.

   [GMPLS-ISIS] K.Kompella et al., "IS-IS Extensions in Support of
                Generalized MPLS", Internet Draft, Work in progress,
                draft-ietf-isis-gmpls-extensions-16.txt, January 2003.

   [GMPLS-OSPF] K.Kompella et al., "OSPF Extensions in Support of
                Generalized MPLS", Internet Draft, Work in progress,
                draft-ietf-ccamp-ospf-gmpls-extensions-08.txt, August
                02.

  [GMPLS-RTG]   K.Kompella et al., "Routing Extensions in Support of
                Generalized MPLS", Internet Draft, Work in Progress,
                draft-ietf-ccamp-gmpls-routing-05.txt, August 2002.

   [ISIS-TE]    T.Li et al., "IS-IS Extensions for Traffic

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                Engineering", Internet Draft, Work in progress, draft-
                ietf-isis-traffic-04.txt, November 2001.

   [LMP]        J.P.Lang (Editor) et al. "Link Management Protocol
                (LMP) û Version 1", Internet Draft, Work in progress,
                draft-ietf-ccamp-lmp-07.txt, October 2002.

   [MPLS-BUNDLE] K.Kompella et al., "Link Bundling in MPLS Traffic
                Engineering", Internet Draft, draft-ietf-mpls-bundle-
                04.txt, August 2002.

   [MPLS-HIER]  K.Kompella et al., "LSP Hierarchy with MPLS TE",
                Internet Draft, Work in progress, draft-ietf-mpls-lsp-
                hierarchy-08.txt, August 2002.

   [OSPF-TE]    D.Katz et al., "Traffic Engineering Extensions to
                OSPF", Internet Draft, Work in progress, draft-katz-
                yeung-ospf-traffic-09.txt, October 2002.

   [RFC-3209]   D.Awduche (Editor) et al., "RSVP-TE: Extensions to RSVP
                for LSP Tunnels", Internet RFC 3209, IETF Proposed
                Standard, December 2001.

   [RFC-3212]   B.Jamoussi (Editor) et al. "Constraint-Based LSP Setup
                using LDP", RFC 3212, IETF Proposed Standard, January
                2002.

  [RFC-3471]    L.Berger (Editor) et al., "Generalized MPLS
                - Signaling Functional Description", RFC 3471, IETF
                Proposed Standard, January 2003.

   [RFC-3472]   L.Berger (Editor) et al., "Generalized MPLS Signaling -
                CR-LDP Extensions", RFC 3472, IETF Proposed Standard,
                January 2003.

   [RFC-3473]   L.Berger (Editor) et al., "Generalized MPLS Signaling -
                RSVP-TE Extensions", RFC 3473, IETF Proposed Standard,
                January 2003.

7.2 Informative References

   [RFC-2119]   Bradner, S., "Key words for use in RFCs to Indicate
                Requirement Levels," RFC 2119.

8. Author's Addresses

   Richard Douville (Alcatel)
   Route de Nozay, 91460 Marcoussis, France
   Phone: +33 1 6963-4431
   Email: richard.douville@alcatel.fr

   Emmanuel Dotaro (Alcatel)
   Route de Nozay, 91460 Marcoussis, France

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   Phone: +33 1 6963-4723
   Email: emmanuel.dotaro@alcatel.fr

   Dimitri Papadimitriou (Alcatel)
   Fr. Wellesplein 1, B-2018 Antwerpen, Belgium
   Phone: +32 3 240-8491
   Email: dimitri.papadimitriou@alcatel.be

   Rauf Izmailov (NEC Laboratories America)
   4 Independence Way, Princeton, NJ 08540, USA
   Phone: +1 609 951-2454
   Email: rauf@nec-lab.com

   Aleksandar Kolarov (NEC Laboratories America)
   4 Independence Way, Princeton, NJ 08540, USA
   Phone: +1 609 951-2985
   Email: kolarov@nec-lab.com

   John Drake (Calient)
   5853 Rue Ferrari, San Jose, CA 95138, USA
   Phone: +1 408 972-3720
   Email: jdrake@calient.net

9. Full Copyright Statement

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