





Network Working Group                                          E. Mannie
Request for Comments: 3946                                    Consultant
Category: Standards Track                               D. Papadimitriou
                                                                 Alcatel
                                                            October 2004


   Generalized Multi-Protocol Label Switching (GMPLS) Extensions for
                Synchronous Optical Network (SONET) and
              Synchronous Digital Hierarchy (SDH) Control

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   This document is a companion to the Generalized Multi-Protocol Label
   Switching (GMPLS) signaling.  It defines the Synchronous Optical
   Network (SONET)/Synchronous Digital Hierarchy (SDH) technology
   specific information needed when using GMPLS signaling.

Table of Contents

   1.  Introduction .................................................  2
   2.  SONET and SDH Traffic Parameters .............................  2
       2.1.  SONET/SDH Traffic Parameters ...........................  3
       2.2.  RSVP-TE Details ........................................  9
       2.3.  CR-LDP Details .........................................  9
   3.  SONET and SDH Labels ......................................... 10
   4.  Acknowledgments .............................................. 15
   5.  Security Considerations ...................................... 16
   6.  IANA Considerations .......................................... 16
   7.  References ................................................... 16
       7.1.  Normative References ................................... 16
   Appendix 1 - Signal Type Values Extension for VC-3 ............... 18
   Annex 1 - Examples ............................................... 18
   Contributors ..................................................... 21
   Authors' Addresses ............................................... 25
   Full Copyright Statement ......................................... 26



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1.  Introduction

   As described in [RFC3945], Generalized MPLS (GMPLS) extends MPLS from
   supporting packet (Packet Switching Capable - PSC) interfaces and
   switching to include support of four new classes of interfaces and
   switching: Layer-2 Switch Capable (L2SC), Time-Division Multiplex
   (TDM), Lambda Switch Capable (LSC) and Fiber-Switch Capable (FSC).  A
   functional description of the extensions to MPLS signaling needed to
   support the new classes of interfaces and switching is provided in
   [RFC3471].  [RFC3473] describes RSVP-TE specific formats and
   mechanisms needed to support all five classes of interfaces, and CR-
   LDP extensions can be found in [RFC3472].  This document presents
   details that are specific to Synchronous Optical Network
   (SONET)/Synchronous Digital Hierarchy (SDH).  Per [RFC3471],
   SONET/SDH specific parameters are carried in the signaling protocol
   in traffic parameter specific objects.

   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].

   Moreover, the reader is assumed to be familiar with the terminology
   in ANSI [T1.105], ITU-T [G.707] as well as [RFC3471], [RFC3472], and
   [RFC3473].  The following abbreviations are used in this document:

   DCC: Data Communications Channel.
   LOVC: Lower Order Virtual Container
   HOVC: Higher Order Virtual Container
   MS: Multiplex Section.
   MSOH: Multiplex Section overhead.
   POH: Path overhead.
   RS: Regenerator Section.
   RSOH: Regenerator section overhead.
   SDH: Synchronous digital hierarchy.
   SOH: Section overhead.
   SONET: Synchronous Optical Network.
   SPE: Synchronous Payload Envelope.
   STM(-N): Synchronous Transport Module (-N) (SDH).
   STS(-N): Synchronous Transport Signal-Level N (SONET).
   VC-n: Virtual Container-n (SDH).
   VTn: Virtual Tributary-n (SONET).

2.  SONET and SDH Traffic Parameters

   This section defines the GMPLS traffic parameters for SONET/SDH.  The
   protocol specific formats, for the SONET/SDH-specific RSVP-TE objects
   and CR-LDP TLVs are described in sections 2.2 and 2.3 respectively.




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   These traffic parameters specify indeed a base set of capabilities
   for SONET ANSI [T1.105] and SDH ITU-T [G.707] such as concatenation
   and transparency.  Other documents may further enhance this set of
   capabilities in the future.  For instance, signaling for SDH over PDH
   ITU-T G.832 or sub-STM-0 ITU-T G.708 interfaces could be defined.

   The traffic parameters defined hereafter (see Section 2.1) MUST be
   used when the label is encoded as SUKLM as defined in this memo (see
   Section 3).  They MUST also be used when requesting one of Section/RS
   or Line/MS overhead transparent STS-1/STM-0, STS-3*N/STM-N (N=1, 4,
   16, 64, 256) signals.

   The traffic parameters and label encoding defined in [RFC3471],
   Section 3.2, MUST be used for fully transparent STS-1/STM-0,
   STS-3*N/STM-N (N=1, 4, 16, 64, 256) signal requests.  A fully
   transparent signal is one for which all overhead is left unmodified
   by intermediate nodes, i.e., when all defined Transparency (T) bits
   would be set if the traffic parameters defined in section 2.1 were
   used.

2.1.  SONET/SDH Traffic Parameters

   The traffic parameters for SONET/SDH are organized as follows:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Signal Type  |      RCC      |              NCC              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              NVC              |        Multiplier (MT)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Transparency (T)                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Profile (P)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Annex 1 lists examples of SONET and SDH signal coding.

   Signal Type (ST): 8 bits

   This field indicates the type of Elementary Signal that comprises the
   requested LSP.  Several transforms can be applied successively on the
   Elementary Signal to build the Final Signal being actually requested
   for the LSP.

   Each transform application is optional and must be ignored if zero,
   except the Multiplier (MT) that cannot be zero and is ignored if
   equal to one.



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   Transforms must be applied strictly in the following order:

   -  First, contiguous concatenation (by using the RCC and NCC fields)
      can be optionally applied on the Elementary Signal, resulting in a
      contiguously concatenated signal.

   -  Second, virtual concatenation (by using the NVC field) can be
      optionally applied on the Elementary Signal resulting in a
      virtually concatenated signal.

   -  Third, some transparency (by using the Transparency field) can be
      optionally specified when requesting a frame as signal rather than
      an SPE or VC based signal.

   -  Fourth, a multiplication (by using the Multiplier field) can be
      optionally applied either directly on the Elementary Signal, or on
      the contiguously concatenated signal obtained from the first
      phase, or on the virtually concatenated signal obtained from the
      second phase, or on these signals combined with some transparency.

   Permitted Signal Type values for SONET/SDH are:

   Value  Type (Elementary Signal)
   -----  ------------------------
    1     VT1.5  SPE / VC-11
    2     VT2    SPE / VC-12
    3     VT3    SPE
    4     VT6    SPE / VC-2
    5     STS-1  SPE / VC-3
    6     STS-3c SPE / VC-4
    7     STS-1      / STM-0   (only when requesting transparency)
    8     STS-3      / STM-1   (only when requesting transparency)
    9     STS-12     / STM-4   (only when requesting transparency)
    10    STS-48     / STM-16  (only when requesting transparency)
    11    STS-192    / STM-64  (only when requesting transparency)
    12    STS-768    / STM-256 (only when requesting transparency)

   A dedicated signal type is assigned to a SONET STS-3c SPE instead of
   coding it as a contiguous concatenation of three STS-1 SPEs.  This is
   done in order to provide easy interworking between SONET and SDH
   signaling.

   Appendix 1 adds one signal type (optional) to the above values.

   Requested Contiguous Concatenation (RCC): 8 bits

   This field is used to request the optional SONET/SDH contiguous
   concatenation of the Elementary Signal.



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   This field is a vector of flags.  Each flag indicates the support of
   a particular type of contiguous concatenation.  Several flags can be
   set at the same time to indicate a choice.

   These flags allow an upstream node to indicate to a downstream node
   the different types of contiguous concatenation that it supports.
   However, the downstream node decides which one to use according to
   its own rules.

   A downstream node receiving simultaneously more than one flag chooses
   a particular type of contiguous concatenation, if any supported, and
   based on criteria that are out of this document scope.  A downstream
   node that doesn't support any of the concatenation types indicated by
   the field must refuse the LSP request.  In particular, it must refuse
   the LSP request if it doesn't support contiguous concatenation at
   all.

   When several flags have been set, the upstream node retrieves the
   (single) type of contiguous concatenation the downstream node has
   selected by looking at the position indicated by the first label and
   the number of label(s) as returned by the downstream node (see also
   Section 3).

   The entire field is set to zero to indicate that no contiguous
   concatenation is requested at all (default value).  A non-zero field
   indicates that some contiguous concatenation is requested.

   The following flag is defined:

      Flag 1 (bit 1): Standard contiguous concatenation.

   Flag 1 indicates that the standard SONET/SDH contiguous concatenation
   as defined in [T1.105]/[G.707] is supported.  Note that bit 1 is the
   low order bit.  Other flags are reserved for extensions, if not used
   they must be set to zero when sent, and should be ignored when
   received.

   See note 1 hereafter in the section on the NCC about the SONET
   contiguous concatenation of STS-1 SPEs when the number of components
   is a multiple of three.

      Number of Contiguous Components (NCC): 16 bits

   This field indicates the number of identical SONET SPEs/SDH VCs
   (i.e., Elementary Signal) that are requested to be concatenated, as
   specified in the RCC field.





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   Note 1: when requesting a SONET STS-Nc SPE with N=3*X, the
      Elementary Signal to use must always be an STS-3c_SPE signal type
      and the value of NCC must always be equal to X.  This allows also
      facilitating the interworking between SONET and SDH.  In
      particular, it means that the contiguous concatenation of three
      STS-1 SPEs can not be requested because according to this
      specification, this type of signal must be coded using the STS-3c
      SPE signal type.

   Note 2: when requesting a transparent STS-N/STM-N signal
      limited to a single contiguously concatenated STS-Nc_SPE/VC-4-Nc,
      the signal type must be STS-N/STM-N, RCC with flag 1 and NCC set
      to 1.

   The NCC value must be consistent with the type of contiguous
   concatenation being requested in the RCC field.  In particular, this
   field is irrelevant if no contiguous concatenation is requested (RCC
   = 0), in that case it must be set to zero when sent, and should be
   ignored when received.  A RCC value different from 0 must imply a
   number of contiguous components greater than 1.

      Number of Virtual Components (NVC): 16 bits

   This field indicates the number of signals that are requested to be
   virtually concatenated.  These signals are all of the same type by
   definition.  They are Elementary Signal SPEs/VCs for which signal
   types are defined in this document, i.e., VT1.5_SPE/VC-11,
   VT2_SPE/VC-12, VT3_SPE, VT6_SPE/VC-2, STS-1_SPE/VC-3 or
   STS-3c_SPE/VC-4.

   This field is set to 0 (default value) to indicate that no virtual
   concatenation is requested.

      Multiplier (MT): 16 bits

   This field indicates the number of identical signals that are
   requested for the LSP, i.e., that form the Final Signal.  These
   signals can be either identical Elementary Signals, or identical
   contiguously concatenated signals, or identical virtually
   concatenated signals.  Note that all these signals belong thus to the
   same LSP.

   The distinction between the components of multiple virtually
   concatenated signals is done via the order of the labels that are
   specified in the signaling.  The first set of labels must describe
   the first component (set of individual signals belonging to the first





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   virtual concatenated signal), the second set must describe the second
   component (set of individual signals belonging to the second virtual
   concatenated signal) and so on.

   This field is set to one (default value) to indicate that exactly one
   instance of a signal is being requested.  Intermediate and egress
   nodes MUST verify that the node itself and the interfaces on which
   the LSP will be established can support the requested multiplier
   value.  If the requested values can not be supported, the receiver
   node MUST generate a PathErr/NOTIFICATION message (see Section
   2.2/2.3, respectively).

   Zero is an invalid value.  If received, the node MUST generate a
   PathErr/NOTIFICATION message (see Section 2.2/2.3, respectively).

   Note 1: when requesting a transparent STS-N/STM-N signal limited to a
   single contiguously concatenated STS-Nc-SPE/VC-4-Nc, the multiplier
   field MUST be equal to 1 (only valid value).

      Transparency (T): 32 bits

   This field is a vector of flags that indicates the type of
   transparency being requested.  Several flags can be combined to
   provide different types of transparency.  Not all combinations are
   necessarily valid.  The default value for this field is zero, i.e.,
   no transparency requested.

   Transparency, as defined from the point of view of this signaling
   specification, is only applicable to the fields in the SONET/SDH
   frame overheads.  In the SONET case, these are the fields in the
   Section Overhead (SOH), and the Line Overhead (LOH).  In the SDH
   case, these are the fields in the Regenerator Section Overhead
   (RSOH), the Multiplex Section overhead (MSOH), and the pointer fields
   between the two.  With SONET, the pointer fields are part of the LOH.

   Note as well that transparency is only applicable when using the
   following Signal Types: STS-1/STM-0, STS-3/STM-1, STS-12/STM-4,
   STS-48/STM-16, STS-192/STM-64 and STS-768/STM-256.  At least one
   transparency type must be specified when requesting such a signal
   type.

   Transparency indicates precisely which fields in these overheads must
   be delivered unmodified at the other end of the LSP.  An ingress LSR
   requesting transparency will pass these overhead fields that must be
   delivered to the egress LSR without any change.  From the ingress and
   egress LSRs point of views, these fields must be seen as unmodified.





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   Transparency is not applied at the interfaces with the initiating and
   terminating LSRs, but is only applied between intermediate LSRs.

   The transparency field is used to request an LSP that supports the
   requested transparency type; it may also be used to setup the
   transparency process to be applied at each intermediate LSR.

   The different transparency flags are the following:

      Flag 1 (bit 1): Section/Regenerator Section layer.
      Flag 2 (bit 2): Line/Multiplex Section layer.

   Where bit 1 is the low order bit.  Other flags are reserved, they
   should be set to zero when sent, and should be ignored when received.
   A flag is set to one to indicate that the corresponding transparency
   is requested.

   Intermediate and egress nodes MUST verify that the node itself and
   the interfaces on which the LSP will be established can support the
   requested transparency.  If the requested flags can not be supported,
   the receiver node MUST generate a PathErr/NOTIFICATION message (see
   Section 2.2/2.3, respectively).

   Section/Regenerator Section layer transparency means that the entire
   frames must be delivered unmodified.  This implies that pointers
   cannot be adjusted.  When using Section/Regenerator Section layer
   transparency all other flags MUST be ignored.

   Line/Multiplex Section layer transparency means that the LOH/MSOH
   must be delivered unmodified.  This implies that pointers cannot be
   adjusted.

   Profile (P): 32 bits

   This field is intended to indicate particular capabilities that must
   be supported for the LSP, for example monitoring capabilities.

   No standard profile is currently defined and this field SHOULD be set
   to zero when transmitted and SHOULD be ignored when received.

   In the future TLV based extensions may be created.










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2.2.  RSVP-TE Details

   For RSVP-TE, the SONET/SDH traffic parameters are carried in the
   SONET/SDH SENDER_TSPEC and FLOWSPEC objects.  The same format is used
   both for SENDER_TSPEC object and FLOWSPEC objects.  The content of
   the objects is defined above in Section 2.1.  The objects have the
   following class and type:

   For SONET ANSI T1.105 and SDH ITU-T G.707:

   SONET/SDH SENDER_TSPEC object: Class = 12, C-Type = 4
   SONET/SDH FLOWSPEC object: Class = 9, C-Type = 4

   There is no Adspec associated with the SONET/SDH SENDER_TSPEC.
   Either the Adspec is omitted or an int-serv Adspec with the Default
   General Characterization Parameters and Guaranteed Service fragment
   is used, see [RFC2210].

   For a particular sender in a session the contents of the FLOWSPEC
   object received in a Resv message SHOULD be identical to the contents
   of the SENDER_TSPEC object received in the corresponding Path
   message.  If the objects do not match, a ResvErr message with a
   "Traffic Control Error/Bad Flowspec value" error SHOULD be generated.

   Intermediate and egress nodes MUST verify that the node itself and
   the interfaces on which the LSP will be established can support the
   requested Signal Type, RCC, NCC, NVC and Multiplier (as defined in
   Section 2.1).  If the requested value(s) can not be supported, the
   receiver node MUST generate a PathErr message with a "Traffic Control
   Error/ Service unsupported" indication (see [RFC2205]).

   In addition, if the MT field is received with a zero value, the node
   MUST generate a PathErr message with a "Traffic Control Error/Bad
   Tspec value" indication (see [RFC2205]).

   Intermediate nodes MUST also verify that the node itself and the
   interfaces on which the LSP will be established can support the
   requested Transparency (as defined in Section 2.1).  If the requested
   value(s) can not be supported, the receiver node MUST generate a
   PathErr message with a "Traffic Control Error/Service unsupported"
   indication (see [RFC2205]).

2.3.  CR-LDP Details

   For CR-LDP, the SONET/SDH traffic parameters are carried in the
   SONET/SDH Traffic Parameters TLV.  The content of the TLV is defined
   above in Section 2.1.  The header of the TLV has the following
   format:



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    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|          Type             |      Length                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The type field for the SONET/SDH Traffic Parameters TLV is: 0x0838.

   Intermediate and egress nodes MUST verify that the node itself and
   the interfaces on which the LSP will be established can support the
   requested Signal Type, RCC, NCC, NVC and Multiplier (as defined in
   Section 2.1).  If the requested value(s) can not be supported, the
   receiver node MUST generate a NOTIFICATION message with a "Resource
   Unavailable" status code (see [RFC3212]).

   In addition, if the MT field is received with a zero value, the node
   MUST generate a NOTIFICATION message with a "Resource Unavailable"
   status code (see [RFC3212]).

   Intermediate nodes MUST also verify that the node itself and the
   interfaces on which the LSP will be established can support the
   requested Transparency (as defined in Section 2.1).  If the requested
   value(s) can not be supported, the receiver node MUST generate a
   NOTIFICATION message with a "Resource Unavailable" status code (see
   [RFC3212]).

3.  SONET and SDH Labels

   SONET and SDH each define a multiplexing structure.  Both structures
   are trees whose roots are respectively an STS-N or an STM-N; and
   whose leaves are the signals that can be transported via the time-
   slots and switched between time-slots within an ingress port and
   time-slots within an egress port, i.e., a VTx SPE, an STS-x SPE or a
   VC-x.  A SONET/SDH label will identify the exact position (i.e.,
   first time-slot) of a particular VTx SPE, STS-x SPE or VC-x signal in
   a multiplexing structure.  SONET and SDH labels are carried in the
   Generalized Label per [RFC3473] and [RFC3472].

   Note that by time-slots we mean the time-slots as they appear
   logically and sequentially in the multiplex, not as they appear after
   any possible interleaving.

   These multiplexing structures will be used as naming trees to create
   unique multiplex entry names or labels.  The same format of label is
   used for SONET and SDH.  As explained in [RFC3471], a label does not
   identify the "class" to which the label belongs.  This is implicitly
   determined by the link on which the label is used.




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   In case of signal concatenation or multiplication, a list of labels
   can appear in the Label field of a Generalized Label.

   In case of contiguous concatenation, only one label appears in the
   Label field.  This label identifies the lowest time-slot occupied by
   the contiguously concatenated signal.  By lowest time-slot we mean
   the one having the lowest label (value) when compared as integer
   values, i.e., the time-slot occupied by the first component signal of
   the concatenated signal encountered when descending the tree.

   In case of virtual concatenation, the explicit ordered list of all
   labels in the concatenation is given.  Each label indicates the first
   time-slot occupied by a component of the virtually concatenated
   signal.  The order of the labels must reflect the order of the
   payloads to concatenate (not the physical order of time-slots).  The
   above representation limits virtual concatenation to remain within a
   single (component) link; it imposes as such a restriction compared to
   the ANSI [T1.105]/ITU-T [G.707] recommendations.

   The standard definition for virtual concatenation allows each virtual
   concatenation components to travel over diverse paths.  Within GMPLS,
   virtual concatenation components must travel over the same
   (component) link if they are part of the same LSP.  This is due to
   the way that labels are bound to a (component) link.  Note however,
   that the routing of components on different paths is indeed
   equivalent to establishing different LSPs, each one having its own
   route.  Several LSPs can be initiated and terminated between the same
   nodes and their corresponding components can then be associated
   together (i.e., virtually concatenated).

   In case of multiplication (i.e., using the multiplier transform), the
   explicit ordered list of all labels that take part in the Final
   Signal is given.  In case of multiplication of virtually concatenated
   signals, the first set of labels indicates the time-slots occupied by
   the first virtually concatenated signal, the second set of labels
   indicates the time-slots occupied by the second virtually
   concatenated signal, and so on.  The above representation limits
   multiplication to remain within a single (component) link.

   The format of the label for SONET and/or SDH TDM-LSR link 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               S               |   U   |   K   |   L   |   M   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





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   This is an extension of the numbering scheme defined in [G.707]
   sections 7.3.7 to 7.3.13, i.e., the (K, L, M) numbering.  Note that
   the higher order numbering scheme defined in [G.707] sections 7.3.1
   to 7.3.6 is not used here.

   Each letter indicates a possible branch number starting at the parent
   node in the multiplex structure.  Branches are considered as numbered
   in increasing order, starting from the top of the multiplexing
   structure.  The numbering starts at 1, zero is used to indicate a
   non-significant or ignored field.

   When a field is not significant or ignored in a particular context it
   MUST be set to zero when transmitted, and MUST be ignored when
   received.

   When a hierarchy of SONET/SDH LSPs is used, a higher order LSP with a
   given bandwidth can be used to carry lower order LSPs.  Remember here
   that a higher order LSP is established through a SONET/SDH higher
   order path layer network and a lower order LSP, through a SONET/SDH
   lower order path layer network (see also ITU-T G.803, Section 3 for
   the corresponding definitions).  In this context, the higher order
   SONET/SDH LSP behaves as a "virtual link" with a given bandwidth
   (e.g., VC-3), it may also be used as a Forwarding Adjacency.  A lower
   order SONET/SDH LSP can be established through that higher order LSP.
   Since a label is local to a (virtual) link, the highest part of that
   label (i.e., the S, U and K fields) is non-significant and is set to
   zero, i.e., the label is "0,0,0,L,M".  Similarly, if the structure of
   the lower order LSP is unknown or not relevant, the lowest part of
   that label (i.e., the L and M fields) is non-significant and is set
   to zero, i.e., the label is "S,U,K,0,0".

   For instance, a VC-3 LSP can be used to carry lower order LSPs.  In
   that case the labels allocated between the two ends of the VC-3 LSP
   for the lower order LSPs will have S, U and K set to zero, i.e.,
   non-significant, while L and M will be used to indicate the signal
   allocated in that VC-3.

   In case of tunneling such as VC-4 containing VC-3 containing
   VC-12/VC-11 where the SUKLM structure is not adequate to represent
   the full signal structure, a hierarchical approach must be used,
   i.e., per layer network signaling.

   The possible values of S, U, K, L and M are defined as follows:

   1. S=1->N is the index of a particular STS-3/AUG-1 inside an
      STS-N/STM-N multiplex.  S is only significant for SONET STS-N
      (N>1) and SDH STM-N (N>0).  S must be 0 and ignored for STS-1 and
      STM-0.



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   2. U=1->3 is the index of a particular STS-1_SPE/VC-3 within an
      STS-3/AUG-1.  U is only significant for SONET STS-N (N>1) and SDH
      STM-N (N>0).  U must be 0 and ignored for STS-1 and STM-0.

   3. K=1->3 is the index of a particular TUG-3 within a VC-4.  K is
      only significant for an SDH VC-4 structured in TUG-3s.  K must be
      0 and ignored in all other cases.

   4. L=1->7 is the index of a particular VT_Group/TUG-2 within an
      STS-1_SPE/TUG-3 or VC-3.  L must be 0 and ignored in all other
      cases.

   5. M is the index of a particular VT1.5_SPE/VC-11, VT2_SPE/VC-12 or
      VT3_SPE within a VT_Group/TUG-2.  M=1->2 indicates a specific VT3
      SPE inside the corresponding VT Group, these values MUST NOT be
      used for SDH since there is no equivalent of VT3 with SDH.  M=3->5
      indicates a specific VT2_SPE/VC-12 inside the corresponding
      VT_Group/TUG-2.  M=6->9 indicates a specific VT1.5_SPE/VC-11
      inside the corresponding VT_Group/TUG-2.

   Note that a label always has to be interpreted according the
   SONET/SDH traffic parameters, i.e., a label by itself does not allow
   knowing which signal is being requested (a label is context
   sensitive).

   The label format defined in this section, referred to as SUKLM, MUST
   be used for any SONET/SDH signal requests that are not transparent
   i.e., when all Transparency (T) bits defined in section 2.1 are set
   to zero.  Any transparent STS-1/STM-0/STS-3*N/STM-N (N=1, 4, 16, 64,
   256) signal request MUST use a label format as defined in [RFC3471].

   The S encoding is summarized in the following table:

    S    SDH                     SONET
   ------------------------------------------------
    0    other                   other
    1    1st AUG-1               1st STS-3
    2    2nd AUG-1               2nd STS-3
    3    3rd AUG-1               3rd STS-3
    4    4rd AUG-1               4rd STS-3
    :    :                       :
    N    Nth AUG-1               Nth STS-3









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   The U encoding is summarized in the following table:

    U    SDH AUG-1               SONET STS-3
   -------------------------------------------------
    0    other                   other
    1    1st VC-3                1st STS-1 SPE
    2    2nd VC-3                2nd STS-1 SPE
    3    3rd VC-3                3rd STS-1 SPE

   The K encoding is summarized in the following table:

    K    SDH VC-4
   ---------------
    0    other
    1    1st TUG-3
    2    2nd TUG-3
    3    3rd TUG-3

   The L encoding is summarized in the following table:

    L    SDH TUG-3    SDH VC-3    SONET STS-1 SPE
   -------------------------------------------------
    0    other        other       other
    1    1st TUG-2    1st TUG-2   1st VTG
    2    2nd TUG-2    2nd TUG-2   2nd VTG
    3    3rd TUG-2    3rd TUG-2   3rd VTG
    4    4th TUG-2    4th TUG-2   4th VTG
    5    5th TUG-2    5th TUG-2   5th VTG
    6    6th TUG-2    6th TUG-2   6th VTG
    7    7th TUG-2    7th TUG-2   7th VTG

   The M encoding is summarized in the following table:

    M    SDH TUG-2                 SONET VTG
   -------------------------------------------------
    0    other                     other
    1    -                         1st VT3 SPE
    2    -                         2nd VT3 SPE
    3    1st VC-12                 1st VT2 SPE
    4    2nd VC-12                 2nd VT2 SPE
    5    3rd VC-12                 3rd VT2 SPE
    6    1st VC-11                 1st VT1.5 SPE
    7    2nd VC-11                 2nd VT1.5 SPE
    8    3rd VC-11                 3rd VT1.5 SPE
    9    4th VC-11                 4th VT1.5 SPE






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   Examples of labels:

   Example 1: the label for the STS-3c_SPE/VC-4 in the Sth STS-3/AUG-1
      is: S>0, U=0, K=0, L=0, M=0.

   Example 2: the label for the VC-3 within the Kth-1 TUG-3 within
      the VC-4 in the Sth AUG-1 is: S>0, U=0, K>0, L=0, M=0.

   Example 3: the label for the Uth-1 STS-1_SPE/VC-3 within the Sth
      STS-3/AUG-1 is: S>0, U>0, K=0, L=0, M=0.

   Example 4: the label for the VT6/VC-2 in the Lth-1 VT Group/TUG-2
      in the Uth-1 STS-1_SPE/VC-3 within the Sth STS-3/AUG-1 is: S>0,
      U>0, K=0, L>0, M=0.

   Example 5: the label for the 3rd VT1.5_SPE/VC-11 in the Lth-1 VT
      Group/TUG-2 within the Uth-1 STS-1_SPE/VC-3 within the Sth STS-
      3/AUG-1 is: S>0, U>0, K=0, L>0, M=8.

   Example 6: the label for the STS-12c/VC-4-4c which uses the 9th
      STS-3/AUG-1 as its first timeslot is: S=9, U=0, K=0, L=0, M=0.

   In case of contiguous concatenation, the label that is used is the
   lowest label (value) of the contiguously concatenated signal as
   explained before.  The higher part of the label indicates where the
   signal starts and the lowest part is not significant.

   In case of STM-0/STS-1, the values of S, U and K must be equal to
   zero according to the field coding rules.  For instance, when
   requesting a VC-3 in an STM-0 the label is S=0, U=0, K=0, L=0, M=0.
   When requesting a VC-11 in a VC-3 in an STM-0 the label is S=0, U=0,
   K=0, L>0, M=6..9.

   Note: when a Section/RS or Line/MS transparent STS-1/STM-0/STS-
   3*N/STM-N (N=1, 4, 16, 64, 256) signal is requested, the SUKLM label
   format and encoding is not applicable and the label encoding MUST
   follow the rules defined in [RFC3471] Section 3.2.

4.  Acknowledgments

   Valuable comments and input were received from the CCAMP mailing list
   where outstanding discussions took place.









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5.  Security Considerations

   This document introduces no new security considerations to either
   [RFC3473] or [RFC3472].  GMPLS security is described in section 11 of
   [RFC3471] and refers to [RFC3209] for RSVP-TE and to [RFC3212] for
   CR-LDP.

6.  IANA Considerations

   Three values have been defined by IANA for this document:

   Two RSVP C-Types in registry:
      http://www.iana.org/assignments/rsvp-parameters

   -  A SONET/SDH SENDER_TSPEC object: Class = 12, C-Type = 4 (see
      section 2.2).

   -  A SONET/SDH FLOWSPEC object: Class = 9, C-Type = 4 (see section
      2.2).

   One LDP TLV Type in registry:
      http://www.iana.org/assignments/ldp-namespaces

   -  A type field for the SONET/SDH Traffic Parameters TLV (see section
      2.3).

7.  References

7.1.  Normative References

   [G.707]      ITU-T Recommendation G.707, "Network Node Interface for
                the Synchronous Digital Hierarchy", October 2000.

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

   [RFC2205]    Braden, R., Zhang, L., Berson, S., Herzog, S., and S.
                Jamin, "Resource ReSerVation Protocol (RSVP) -- Version
                1 Functional Specification", RFC 2205, September 1997.

   [RFC2210]    Wroclawski, J., "The Use of RSVP with IETF Integrated
                Services", RFC 2210, September 1997.

   [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.





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RFC 3946         GMPLS Extensions for SONET/SDH Control     October 2004


   [RFC3212]    Jamoussi, B., Andersson, L., Callon, R., Dantu, R., Wu,
                L., Doolan, P., Worster, T., Feldman, N., Fredette, A.,
                Girish, M., Gray, E., Heinanen, J., Kilty, T., and A.
                Malis, "Constraint-Based LSP Setup using LDP", RFC 3212,
                January 2002.

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

   [RFC3472]    Ashwood-Smith, P. and L. Berger, "Generalized
                Multi-Protocol Label Switching (MPLS) Signaling
                - Constraint-based Routed Label Distribution Protocol
                (CR-LDP) Extensions", RFC 3472, January 2003.

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

   [RFC3945]    Mannie, E., Ed., "Generalized Multiprotocol Label
                Switching (GMPLS) Architecture", RFC 3945, October 2004.

   [T1.105]     "Synchronous Optical Network (SONET): Basic Description
                Including Multiplex Structure, Rates, and Formats", ANSI
                T1.105, October 2000.

























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Appendix 1 - Signal Type Values Extension for VC-3

   This appendix defines the following optional additional Signal Type
   value for the Signal Type field of section 2.1:

   Value         Type
   -----  ---------------------
    20     "VC-3 via AU-3 at the end"

   According to the ITU-T [G.707] recommendation a VC-3 in the TU-
   3/TUG-3/VC-4/AU-4 branch of the SDH multiplex cannot be structured in
   TUG-2s, however a VC-3 in the AU-3 branch can be. In addition, a VC-3
   could be switched between the two branches if required.

   A VC-3 circuit could be terminated on an ingress interface of an LSR
   (e.g., forming a VC-3 forwarding adjacency). This LSR could then want
   to demultiplex this VC-3 and switch internal low order LSPs. For
   implementation reasons, this could be only possible if the LSR
   receives the VC-3 in the AU-3 branch.  E.g., for an LSR not able to
   switch internally from a TU-3 branch to an AU-3 branch on its
   incoming interface before demultiplexing and then switching the
   content with its switch fabric.

   In that case it is useful to indicate that the VC-3 LSP must be
   terminated at the end in the AU-3 branch instead of the TU-3 branch.

   This is achieved by using the "VC-3 via AU-3 at the end" signal type.
   This information can be used, for instance, by the penultimate LSR to
   switch an incoming VC-3 received in any branch to the AU-3 branch on
   the outgoing interface to the destination LSR.

   The "VC-3 via AU-3 at the end" signal type does not imply that the
   VC-3 must be switched via the AU-3 branch at some other places in the
   network. The VC-3 signal type just indicates that a VC-3 in any
   branch is suitable.

Annex 1 - Examples

   This annex defines examples of SONET and SDH signal coding. Their
   objective is to help the reader to understand how works the traffic
   parameter coding and not to give examples of typical SONET or SDH
   signals.

   As stated above, signal types are Elementary Signals to which
   successive concatenation, multiplication and transparency transforms
   can be applied to obtain Final Signals.





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   1.   A VC-4 signal is formed by the application of RCC with value 0,
        NCC with value 0, NVC with value 0, MT with value 1 and T with
        value 0 to a VC-4 Elementary Signal.

   2.   A VC-4-7v signal is formed by the application of RCC with value
        0, NCC with value 0, NVC with value 7 (virtual concatenation of
        7 components), MT with value 1 and T with value 0 to a VC-4
        Elementary Signal.

   3.   A VC-4-16c signal is formed by the application of RCC with flag
        1 (standard contiguous concatenation), NCC with value 16, NVC
        with value 0, MT with value 1 and T with value 0 to a VC-4
        Elementary Signal.

   4.   An STM-16 signal with Multiplex Section layer transparency is
        formed by the application of RCC with value 0, NCC with value 0,
        NVC with value 0, MT with value 1 and T with flag 2 to an STM-16
        Elementary Signal.

   5.   An STM-4 signal with Multiplex Section layer transparency is
        formed by the application of RCC with flag 0, NCC with value 0,
        NVC with value 0, MT with value 1 and T with flag 2 applied to
        an STM-4 Elementary Signal.

   6.   An STM-256 signal with Multiplex Section layer transparency is
        formed by the application of RCC with flag 0, NCC with value 0,
        NVC with value 0, MT with value 1 and T with flag 2 applied to
        an STM-256 Elementary Signal.

   7.   An STS-1 SPE signal is formed by the application of RCC with
        value 0, NCC with value 0, NVC with value 0, MT with value 1 and
        T with value 0 to an STS-1 SPE Elementary Signal.

   8.   An STS-3c SPE signal is formed by the application of RCC with
        value 1 (standard contiguous concatenation), NCC with value 1,
        NVC with value 0, MT with value 1 and T with value 0 to an STS-
        3c SPE Elementary Signal.

   9.   An STS-48c SPE signal is formed by the application of RCC with
        flag 1 (standard contiguous concatenation), NCC with value 16,
        NVC with value 0, MT with value 1 and T with value 0 to an STS-
        3c SPE Elementary Signal.

   10.  An STS-1-3v SPE signal is formed by the application of RCC with
        value 0, NVC with value 3 (virtual concatenation of 3
        components), MT with value 1 and T with value 0 to an STS-1 SPE
        Elementary Signal.




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   11.  An STS-3c-9v SPE signal is formed by the application of RCC with
        value 1, NCC with value 1, NVC with value 9 (virtual
        concatenation of 9 STS-3c), MT with value 1 and T with value 0
        to an STS-3c SPE Elementary Signal.

   12.  An STS-12 signal with Section layer (full) transparency is
        formed by the application of RCC with value 0, NVC with value 0,
        MT with value 1 and T with flag 1 to an STS-12 Elementary
        Signal.

   13.  3 x STS-768c SPE signal is formed by the application of RCC with
        flag 1, NCC with value 256, NVC with value 0, MT with value 3,
        and T with value 0 to an STS-3c SPE Elementary Signal.

   14.  5 x VC-4-13v composed signal is formed by the application of RCC
        with value 0, NVC with value 13, MT with value 5 and T with
        value 0 to a VC-4 Elementary Signal.

   The encoding of these examples is summarized in the following table:

   Signal                     ST   RCC   NCC   NVC   MT   T
   --------------------------------------------------------
   VC-4                        6     0     0     0    1   0
   VC-4-7v                     6     0     0     7    1   0
   VC-4-16c                    6     1    16     0    1   0
   STM-16 MS transparent      10     0     0     0    1   2
   STM-4 MS transparent        9     0     0     0    1   2
   STM-256 MS transparent     12     0     0     0    1   2
   STS-1 SPE                   5     0     0     0    1   0
   STS-3c SPE                  6     1     1     0    1   0
   STS-48c SPE                 6     1    16     0    1   0
   STS-1-3v SPE                5     0     0     3    1   0
   STS-3c-9v SPE               6     1     1     9    1   0
   STS-12 Section transparent  9     0     0     0    1   1
   3 x STS-768c SPE            6     1   256     0    3   0
   5 x VC-4-13v                6     0     0    13    5   0















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Contributors

   Contributors are listed by alphabetical order:

   Stefan Ansorge (Alcatel)
   Lorenzstrasse 10
   70435 Stuttgart, Germany

   EMail: stefan.ansorge@alcatel.de


   Peter Ashwood-Smith (Nortel)
   PO. Box 3511 Station C,
   Ottawa, ON K1Y 4H7, Canada

   EMail:petera@nortelnetworks.com


   Ayan Banerjee (Calient)
   5853 Rue Ferrari
   San Jose, CA 95138, USA

   EMail: abanerjee@calient.net


   Lou Berger (Movaz)
   7926 Jones Branch Drive
   McLean, VA 22102, USA

   EMail: lberger@movaz.com


   Greg Bernstein (Ciena)
   10480 Ridgeview Court
   Cupertino, CA 94014, USA

   EMail: greg@ciena.com


   Angela Chiu (Celion)
   One Sheila Drive, Suite 2
   Tinton Falls, NJ 07724-2658

   EMail: angela.chiu@celion.com







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   John Drake (Calient)
   5853 Rue Ferrari
   San Jose, CA 95138, USA

   EMail: jdrake@calient.net


   Yanhe Fan (Axiowave)
   100 Nickerson Road
   Marlborough, MA 01752, USA

   EMail: yfan@axiowave.com


   Michele Fontana (Alcatel)
   Via Trento 30,
   I-20059 Vimercate, Italy

   EMail: michele.fontana@alcatel.it


   Gert Grammel (Alcatel)
   Lorenzstrasse, 10
   70435 Stuttgart, Germany

   EMail: gert.grammel@alcatel.de


   Juergen Heiles (Siemens)
   Hofmannstr. 51
   D-81379 Munich, Germany

   EMail: juergen.heiles@siemens.com


   Suresh Katukam (Cisco)
   1450 N. McDowell Blvd,
   Petaluma, CA 94954-6515, USA

   EMail: suresh.katukam@cisco.com


   Kireeti Kompella (Juniper)
   1194 N. Mathilda Ave.
   Sunnyvale, CA 94089, USA

   EMail: kireeti@juniper.net




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   Jonathan P. Lang (Calient)
   25 Castilian
   Goleta, CA 93117, USA

   EMail: jplang@calient.net


   Fong Liaw (Solas Research)

   EMail: fongliaw@yahoo.com


   Zhi-Wei Lin (Lucent)
   101 Crawfords Corner Rd
   Holmdel, NJ  07733-3030, USA

   EMail: zwlin@lucent.com


   Ben Mack-Crane (Tellabs)

   EMail: ben.mack-crane@tellabs.com


   Dimitrios Pendarakis (Tellium)
   2 Crescent Place, P.O. Box 901
   Oceanport, NJ 07757-0901, USA

   EMail: dpendarakis@tellium.com


   Mike Raftelis (White Rock)
   18111 Preston Road
   Dallas, TX 75252, USA


   Bala Rajagopalan (Tellium)
   2 Crescent Place, P.O. Box 901
   Oceanport, NJ 07757-0901, USA

   EMail: braja@tellium.com









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   Yakov Rekhter (Juniper)
   1194 N. Mathilda Ave.
   Sunnyvale, CA 94089, USA

   EMail: yakov@juniper.net


   Debanjan Saha (Tellium)
   2 Crescent Place, P.O. Box 901
   Oceanport, NJ 07757-0901, USA

   EMail: dsaha@tellium.com


   Vishal Sharma (Metanoia)
   335 Elan Village Lane
   San Jose, CA 95134, USA

   EMail: vsharma87@yahoo.com


   George Swallow (Cisco)
   250 Apollo Drive
   Chelmsford, MA 01824, USA

   EMail: swallow@cisco.com


   Z. Bo Tang (Tellium)
   2 Crescent Place, P.O. Box 901
   Oceanport, NJ 07757-0901, USA

   EMail: btang@tellium.com


   Eve Varma (Lucent)
   101 Crawfords Corner Rd
   Holmdel, NJ  07733-3030, USA

   EMail: evarma@lucent.com


   Yangguang Xu (Lucent)
   21-2A41, 1600 Osgood Street
   North Andover, MA 01845, USA

   EMail: xuyg@lucent.com




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Authors' Addresses

   Eric Mannie (Consultant)
   Avenue de la Folle Chanson, 2
   B-1050 Brussels, Belgium
   Phone:  +32 2 648-5023
   Mobile: +32 (0)495-221775

   EMail:  eric_mannie@hotmail.com


   Dimitri Papadimitriou (Alcatel)
   Francis Wellesplein 1,
   B-2018 Antwerpen, Belgium
   Phone:  +32 3 240-8491

   EMail:  dimitri.papadimitriou@alcatel.be


































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Full Copyright Statement

   Copyright (C) The Internet Society (2004).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
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   Copies of IPR disclosures made to the IETF Secretariat and any
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   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
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   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.







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