Internet Engineering Task Force (IETF)                     F. Zhang, Ed.
Request for Comments: 7139                                        Huawei
Updates: 4328                                                   G. Zhang
Category: Standards Track                                           CATR
ISSN: 2070-1721                                               S. Belotti
                                                          Alcatel-Lucent
                                                           D. Ceccarelli
                                                                Ericsson
                                                             K. Pithewan
                                                                Infinera
                                                           February
                                                              March 2014

                       GMPLS Signaling Extensions
        for Control of Evolving G.709 Optical Transport Networks

Abstract

   ITU-T Recommendation G.709 [G709-2012] introduced new Optical channel
   Data Unit (ODU) containers (ODU0, ODU4, ODU2e, and ODUflex) and
   enhanced Optical Transport Network (OTN) flexibility.

   This document updates the ODU-related portions of RFC 4328 to provide
   extensions to GMPLS signaling to control the full set of OTN
   features, including ODU0, ODU4, ODU2e, and ODUflex.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7139.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................3
   2. Terminology .....................................................3
   3. GMPLS Extensions for the Evolving G.709 -- Overview .............3
   4. Generalized Label Request .......................................4
   5. Extensions for Traffic Parameters for the Evolving G.709 ........7
      5.1. Usage of ODUflex(CBR) Traffic Parameters ...................8
      5.2. Usage of ODUflex(GFP) Traffic Parameters ..................10
      5.3. Notification on Errors of OTN-TDM Traffic Parameters ......11
   6. Generalized Label ..............................................12
      6.1. OTN-TDM Switching Type Generalized Label ..................12
      6.2. Procedures ................................................14
           6.2.1. Notification on Label Error ........................16
      6.3. Supporting Virtual Concatenation and Multiplication .......16
      6.4. Examples ..................................................17
   7. Supporting Hitless Adjustment of ODUflex(GFP) ..................18
   8. Operations, Administration, and Maintenance (OAM)
      Considerations .................................................20
   9. Control-Plane Backward-Compatibility Considerations ............20
   10. Security Considerations .......................................21
   11. IANA Considerations ...........................................21
   12. References ....................................................23
      12.1. Normative References .....................................23
      12.2. Informative References ...................................24
   13. Contributors ..................................................24
   14. Acknowledgments ...............................................26

1.  Introduction

   With the evolution and deployment of Optical Transport Network (OTN)
   technology, it is necessary that appropriate enhanced control
   technology support be provided for [G709-2012].

   [RFC7062] provides a framework to allow the development of protocol
   extensions to support GMPLS and Path Computation Element (PCE)
   control of OTN as specified in [G709-2012].  Based on this framework,
   [RFC7096] evaluates the information needed by the routing and
   signaling process in OTNs to support GMPLS control of OTN.

   [RFC4328] describes the control technology details that are specific
   to the 2001 revision of the G.709 specification.  This document
   updates the ODU-related portions of [RFC4328] to provide Resource
   Reservation Protocol - Traffic Engineering (RSVP-TE) extensions to
   support control for [G709-2012].

2.  Terminology

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

3.  GMPLS Extensions for the Evolving G.709 -- Overview

   New features for the evolving OTN, for example, new ODU0, ODU2e,
   ODU4, and ODUflex containers, are specified in [G709-2012].  The
   corresponding new Signal Types are summarized below:

   -  Optical channel Transport Unit (OTUk):
      o  OTU4

   -  Optical channel Data Unit (ODUk):
      o  ODU0
      o  ODU2e
      o  ODU4
      o  ODUflex

   A new tributary slot granularity (i.e., 1.25 Gbps) is also described
   in [G709-2012].  Thus, there are now two tributary slot (TS)
   granularities for the foundation OTN ODU1, ODU2, and ODU3 containers.
   The TS granularity at 2.5 Gbps is used on the legacy interfaces while
   the new 1.25 Gbps is used on the new interfaces.

   In addition to the support of ODUk mapping into OTUk (k = 1, 2, 3,
   4), [G709-2012] encompasses the multiplexing of ODUj (j = 0, 1, 2,
   2e, 3, flex) into an ODUk (k > j), as described in Section 3.1.2 of
   [RFC7062].

   Virtual Concatenation (VCAT) of Optical channel Payload Unit-k (OPUk)
   (OPUk-Xv, k = 1/2/3, X = 1...256) is also supported by [G709-2012].
   Note that VCAT of OPU0 / OPU2e / OPU4 / OPUflex is not supported per
   [G709-2012].

   [RFC4328] describes GMPLS signaling extensions to support the control
   for the 2001 revision of the G.709 specification.  However, [RFC7096]
   does not provide the means to signal all the new Signal Types and
   related mapping and multiplexing functionalities.  Moreover, it
   supports only the deprecated auto-MSI (Multiframe Structure
   Identifier) mode, which assumes that the Tributary Port Number (TPN)
   is automatically assigned in the transmit direction and not checked
   in the receive direction.

   This document extends the G.709 Traffic Parameters described in
   [RFC4328] and presents a new flexible and scalable OTN-TDM
   Generalized Label format.  (Here, TDM refers to Time-Division
   Multiplexing.)  Additionally, procedures about Tributary Port Number
   assignment through the control plane are also provided in this
   document.

4.  Generalized Label Request

   The GENERALIZED_LABEL_REQUEST object, as described in [RFC3471],
   carries the Label Switched Path (LSP) Encoding Type, the Switching
   Type, and the Generalized Protocol Identifier (G-PID).

   [RFC4328] extends the GENERALIZED_LABEL_REQUEST object, introducing
   two new code-points for the LSP Encoding Type (i.e., G.709 ODUk
   (Digital Path) and G.709 Optical Channel) and adding a list of G-PID
   values in order to accommodate the 2001 revision of the G.709
   specification.

   This document follows these extensions and introduces a new Switching
   Type to indicate the ODUk Switching Capability [G709-2012] in order
   to support backward compatibility with [RFC4328], as described in
   [RFC7062].  The new Switching Type (OTN-TDM Switching Type) is
   defined in [RFC7138].

   This document also updates the G-PID values defined in [RFC4328]:

   Value    G-PID Type
   -----    ----------

   47       Type field updated from "G.709 ODUj" to "ODU-2.5G" to
            indicate transport of Digital Paths (e.g., at 2.5, 10, and
            40 Gbps) via 2.5 Gbps TS granularity.

   56       Type field updated from "ESCON" to "SBCON/ESCON" to align
            with [G709-2012] payload type 0x1A.

   Note: Value 47 includes mapping of Synchronous Digital Hierarchy
   (SDH).

   In the case of ODU multiplexing, the Lower Order ODU (LO ODU) (i.e.,
   the client signal) may be multiplexed into a Higher Order ODU (HO
   ODU) via 1.25G TS granularity, 2.5G TS granularity, or ODU-any.
   Since the G-PID type "ODUk" defined in [RFC4328] is only used for 2.5
   Gbps TS granularity, two new G-PID types are defined as follows:

   -  ODU-1.25G:  Transport of Digital Paths at 1.25, 2.5, 10, 40, and
                  100 Gbps via 1.25 Gbps TS granularity.

   -  ODU-any:    Transport of Digital Paths at 1.25, 2.5, 10, 40, and
                  100 Gbps via 1.25 or 2.5 Gbps TS granularity (i.e.,
                  the fallback procedure is enabled and the default
                  value of 1.25 Gbps TS granularity can fall back to 2.5
                  Gbps if needed).

   The full list of payload types defined in [G709-2012] and their
   mapping to existing and new G-PID types are as follows:

     G.709
    Payload
     Type     G-PID        Type/Comment             LSP Encoding
     ====     =====    =====================     ===================
     0x01              No standard value
     0x02      49      CBRa                      G.709 ODUk
     0x03      50      CBRb                      G.709 ODUk
     0x04      32      ATM                       G.709 ODUk
     0x05      59      Framed GFP                G.709 ODUk
               54      Ethernet MAC (framed GFP) G.709 ODUk
               70      64B/66B GFP-F Ethernet    G.709 ODUk (k=2)
     0x06              Not signaled
     0x07      55      Ethernet PHY              G.709 ODUk (k=0,3,4)
                       (transparent GFP)
     0x08      58      Fiber Channel             G.709 ODUk (k=2e)
     0x09      59      Framed GFP                G.709 ODUk (k=2)
               70      64B/66B GFP-F Ethernet    G.709 ODUk (k=2)
     0x0A      60      STM-1                     G.709 ODUk (k=0)
     0x0B      61      STM-4                     G.709 ODUk (k=0)
     0x0C      58      Fiber Channel             G.709 ODUk (k=0)
     0x0D      58      Fiber Channel             G.709 ODUk (k=1)
     0x0E      58      Fiber Channel             G.709 ODUflex
     0x0F      58      Fiber Channel             G.709 ODUflex
     0x10      51      BSOT                      G.709 ODUk
     0x11      52      BSNT                      G.709 ODUk
     0x12      62      InfiniBand                G.709 ODUflex
     0x13      62      InfiniBand                G.709 ODUflex
     0x14      62      InfiniBand                G.709 ODUflex
     0x15      63      Serial Digital Interface  G.709 ODUk (k=0)
     0x16      64      SDI/1.001                 G.709 ODUk (k=1)
     0x17      63      Serial Digital Interface  G.709 ODUk (k=1)
     0x18      64      SDI/1.001                 G.709 ODUflex
     0x19      63      Serial Digital Interface  G.709 ODUflex
     0x1A      56      SBCON/ESCON               G.709 ODUk (k=0)
     0x1B      65      DVB_ASI                   G.709 ODUk (k=0)
     0x1C      58      Fiber Channel             G.709 ODUk
     0x20      47      G.709 ODU-2.5G            G.709 ODUk (k=2,3)
               66      G.709 ODU-1.25G           G.709 ODUk (k=1)
     0x21      66      G.709 ODU-1.25G           G.709 ODUk (k=2,3,4)
               67      G.709 ODU-any             G.709 ODUk (k=2,3)
     0x55              No standard value
     0x66              No standard value
     0x80-0x8F         No standard value
     0xFD      68      Null Test                 G.709 ODUk
     0xFE      69      Random Test               G.709 ODUk
     0xFF              No standard value

   Note: Values 59 and 70 include mapping of SDH.

   Note that the mapping types for ODUj into OPUk are unambiguously per
   Table 7-10 of [G709-2012], so there is no need to carry mapping type
   information in the signaling.

   Note also that additional information on G.709 client mapping can be
   found in [G7041].

5.  Extensions for Traffic Parameters for Evolving G.709 OTNs

   The Traffic Parameters for the OTN-TDM-capable Switching Type are
   carried in the OTN-TDM SENDER_TSPEC object in the Path message and
   the OTN-TDM FLOWSPEC object in the Resv message.  The objects have
   the following class and type:

   -  OTN-TDM SENDER_TSPEC object: Class = 12, C-Type = 7
   -  OTN-TDM FLOWSPEC object: Class = 9, C-Type = 7

   The format of Traffic Parameters in these two objects is defined 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  |                       Reserved                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              NVC              |        Multiplier (MT)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            Bit_Rate                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Signal Type: 8 bits

      As defined in Section 3.2.1 of [RFC4328], with the following
      additional values:

      Value    Type
      -----    ----
      4        ODU4 (i.e., 100 Gbps)
      9        OCh at 100 Gbps
      10       ODU0 (i.e., 1.25 Gbps)
      11       ODU2e (i.e., 10 Gbps for FC1200 and GE LAN)
      12-19    Reserved (for future use)
      20       ODUflex(CBR) (i.e., 1.25*N Gbps)
      21       ODUflex(GFP-F), resizable (i.e., 1.25*N Gbps)
      22       ODUflex(GFP-F), non-resizable (i.e., 1.25*N Gbps)
      23-255   Reserved (for future use)

   Note: Above, CBR stands for Constant Bit Rate, and GFP-F stands for
   Generic Framing Procedure - Framed.

   NVC (Number of Virtual Components): 16 bits

      As defined in Section 3.2.3 of [RFC4328].  This field MUST be set
      to 0 for ODUflex Signal Types.

   Multiplier (MT): 16 bits

      As defined in Section 3.2.4 of [RFC4328].  This field MUST be set
      to 1 for ODUflex Signal Types.

   Bit_Rate: 32 bits

      In the case of ODUflex, including ODUflex(CBR) and ODUflex(GFP)
      Signal Types, this field indicates the nominal bit rate of ODUflex
      expressed in bytes per second, encoded as a 32-bit IEEE single-
      precision floating-point number (referring to [RFC4506] and
      [IEEE]).  For other Signal Types, this field MUST be set to zero
      on transmission, MUST be ignored on receipt, and SHOULD be passed
      unmodified by transit nodes.

5.1.  Usage of ODUflex(CBR) Traffic Parameters

   In the case of ODUflex(CBR), the Bit_Rate information carried in the
   ODUflex Traffic Parameters MUST be used to determine the actual
   bandwidth of ODUflex(CBR) (i.e., Bit_Rate * (1 +/- Tolerance)).
   Therefore, the total number of tributary slots N in the HO ODUk link
   can be reserved correctly.  Where:

         N = Ceiling of

   ODUflex(CBR) nominal bit rate * (1 + ODUflex(CBR) bit rate tolerance)
   ---------------------------------------------------------------------
       ODTUk.ts nominal bit rate * (1 - HO OPUk bit rate tolerance)

   In this formula, the ODUflex(CBR) nominal bit rate is the bit rate of
   the ODUflex(CBR) on the line side, i.e., the client signal bit rate
   after applying the 239/238 factor (according to Clause 7.3, Table 7-2
   of [G709-2012]) and the transcoding factor T (if needed) on the CBR
   client.  According to Clauses 17.7.3, 17.7.4, and 17.7.5 of
   [G709-2012]:

   ODUflex(CBR) nominal bit rate = CBR client bit rate * (239/238) / T

   The ODTUk.ts (Optical channel Data Tributary Unit k with ts tributary
   slots) nominal bit rate is the nominal bit rate of the tributary slot
   of ODUk, as shown in Table 1 (referring to Table 7-7 of [G709-2012]).

      ODUk.ts       Minimum          Nominal          Maximum
      -----------------------------------------------------------
      ODU2.ts    1,249,384.632    1,249,409.620     1,249,434.608
      ODU3.ts    1,254,678.635    1,254,703.729     1,254,728.823
      ODU4.ts    1,301,683.217    1,301,709.251     1,301,735.285

              Table 1: Actual TS Bit Rate of ODUk (in Kbps)

   Note that:

      Minimum bit rate of ODUTk.ts =
         ODTUk.ts nominal bit rate * (1 - HO OPUk bit rate tolerance)

      Maximum bit rate of ODTUk.ts =
         ODTUk.ts nominal bit rate * (1 + HO OPUk bit rate tolerance)

      Where: HO OPUk bit rate tolerance = 20 ppm (parts per million)

   Note that the bit rate tolerance is implicit in Signal Type and the
   ODUflex(CBR) bit rate tolerance is fixed and it is equal to 100 ppm
   as described in Table 7-2 of [G709-2012].

   Therefore, a node receiving a Path message containing an ODUflex(CBR)
   nominal bit rate can allocate a precise number of tributary slots and
   set up the cross-connection for the ODUflex service.

   Note that for different ODUk, the bit rates of the tributary slots
   are different, so the total number of tributary slots to be reserved
   for the ODUflex(CBR) may not be the same on different HO ODUk links.

   An example is given below to illustrate the usage of ODUflex(CBR)
   Traffic Parameters.

       +-----+             +---------+             +-----+
       |     +-------------+ +-----+ +-------------+     |
       |     +=============+\| ODU |/+=============+     |
       |     +=============+/| flex+-+=============+     |
       |     +-------------+ |     |\+=============+     |
       |     +-------------+ +-----+ +-------------+     |
       |     |             |         |             |     |
       |     |   .......   |         |   .......   |     |
       |  A  +-------------+    B    +-------------+  C  |
       +-----+   HO ODU4   +---------+   HO ODU2   +-----+

         =========: TSs occupied by ODUflex
         ---------: available TSs

       Figure 1: Example of ODUflex(CBR) Traffic Parameters
   As shown in Figure 1, assume there is an ODUflex(CBR) service
   requesting a bandwidth of 2.5 Gbps from node A to node C.

   In other words, the ODUflex Traffic Parameters indicate that Signal
   Type is 20 (ODUflex(CBR)) and Bit_Rate is 2.5 Gbps (note that the
   tolerance is not signaled as explained above).

   -  On the HO ODU4 link between node A and B:

      The maximum bit rate of the ODUflex(CBR) equals 2.5 Gbps * (1 +
      100 ppm), and the minimum bit rate of the tributary slot of ODU4
      equals 1,301,683.217 Kbps, so the total number of tributary slots
      N1 to be reserved on this link is:

      N1 = ceiling (2.5 Gbps * (1 + 100 ppm) / 1,301,683.217 Kbps) = 2

   -  On the HO ODU2 link between node B and C:

      The maximum bit rate of the ODUflex equals 2.5 Gbps * (1 + 100
      ppm), and the minimum bit rate of the tributary slot of ODU2
      equals 1,249,384.632 Kbps, so the total number of tributary slots
      N2 to be reserved on this link is:

      N2 = ceiling (2.5 Gbps * (1 + 100 ppm) / 1,249,384.632 Kbps) = 3

5.2.  Usage of ODUflex(GFP) Traffic Parameters

   [G709-2012] recommends that the ODUflex(GFP) fill an integral number
   of tributary slots of the smallest HO ODUk path over which the
   ODUflex(GFP) may be carried, as shown in Table 2.

                 ODU Type              | Nominal Bit Rate | Tolerance
      ---------------------------------+------------------+-----------
      ODUflex(GFP) of n TSs, 1<=n<=8   |   n * ODU2.ts    | +/-100 ppm
      ODUflex(GFP) of n TSs, 9<=n<=32  |   n * ODU3.ts    | +/-100 ppm
      ODUflex(GFP) of n TSs, 33<=n<=80 |   n * ODU4.ts    | +/-100 ppm

         Table 2: Recommended ODUflex(GFP) Bit Rates and Tolerance

   According to this table, the Bit_Rate field for ODUflex(GFP) MUST be
   equal to one of the 80 values listed below:

           1 * ODU2.ts;  2 * ODU2.ts; ...;  8 * ODU2.ts;
           9 * ODU3.ts; 10 * ODU3.ts, ...; 32 * ODU3.ts;
          33 * ODU4.ts; 34 * ODU4.ts; ...; 80 * ODU4.ts.

   In this way, the number of required tributary slots for the
   ODUflex(GFP) (i.e., the value of "n" in Table 2) can be deduced from
   the Bit_Rate field.

5.3.  Notification on Errors of OTN-TDM Traffic Parameters

   There is no Adspec associated with the OTN-TDM SENDER_TSPEC object.
   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 OTN-TDM
   FLOWSPEC object received in a Resv message SHOULD be identical to the
   contents of the OTN-TDM 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 MUST
   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, NVC, and Bit_Rate values.  If the requested
   value(s) cannot 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]).

   Further, if the Signal Type is not ODU1, ODU2, or ODU3, and the NVC
   field is not 0, the node MUST generate a PathErr message with a
   "Traffic Control Error/Bad Tspec value" indication (see [RFC2205]).

6.  Generalized Label

   This section defines the format of the OTN-TDM Generalized Label.

6.1.  OTN-TDM Switching Type Generalized Label

   The following is the GENERALIZED_LABEL object format that MUST be
   used with the OTN-TDM Switching Type:

     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |         TPN           |   Reserved    |        Length         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ~                   Bit Map          ......                     ~
    ~              ......                   |     Padding Bits      ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The OTN-TDM GENERALIZED_LABEL object is used to indicate how the LO
   ODUj signal is multiplexed into the HO ODUk link.  Note that the LO
   OUDj Signal Type is indicated by Traffic Parameters, while the type
   of HO ODUk link is identified by the selected interface carried in
   the IF_ID RSVP_HOP object.

   TPN: 12 bits

      Indicates the TPN for the assigned tributary slot(s).

      -  In the case of an LO ODUj multiplexed into an HO
         ODU1/ODU2/ODU3, only the lower 6 bits of the TPN field are
         significant; the other bits of the TPN field MUST be set to 0.

      -  In the case of an LO ODUj multiplexed into an HO ODU4, only the
         lower 7 bits of the TPN field are significant; the other bits
         of the TPN field MUST be set to 0.

      -  In the case of ODUj mapped into OTUk (j=k), the TPN is not
         needed, and this field MUST be set to 0.

      Per [G709-2012], the TPN is used to allow for correct
      demultiplexing in the data plane.  When an LO ODUj is multiplexed
      into an HO ODUk occupying one or more TSs, a new TPN value is
      configured at the two ends of the HO ODUk link and is put into the
      related MSI byte(s) in the OPUk overhead at the (traffic) ingress
      end of the link, so that the other end of the link can learn which
      TS(s) is/are used by the LO ODUj in the data plane.

      According to [G709-2012], the TPN field MUST be set according to
      the following tables:

      +-------+-------+----+-------------------------------------------+
      |HO ODUk|LO ODUj|TPN |          TPN Assignment Rules             |
      +-------+-------+----+-------------------------------------------+
      | ODU2  | ODU1  |1-4 |Fixed, = TS# occupied by ODU1              |
      +-------+-------+----+-------------------------------------------+
      |       | ODU1  |1-16|Fixed, = TS# occupied by ODU1              |
      | ODU3  +-------+----+-------------------------------------------+
      |       | ODU2  |1-4 |Flexible, != other existing LO ODU2s' TPNs |
      +-------+-------+----+-------------------------------------------+

             Table 3: TPN Assignment Rules (2.5 Gbps TS Granularity)

      +-------+-------+----+-------------------------------------------+
      |HO ODUk|LO ODUj|TPN |          TPN Assignment Rules             |
      +-------+-------+----+-------------------------------------------+
      | ODU1  | ODU0  |1-2 |Fixed, = TS# occupied by ODU0              |
      +-------+-------+----+-------------------------------------------+
      |       | ODU1  |1-4 |Flexible, != other existing LO ODU1s' TPNs |
      | ODU2  +-------+----+-------------------------------------------+
      |       |ODU0 & |1-8 |Flexible, != other existing LO ODU0s and   |
      |       |ODUflex|    |ODUflexes' TPNs                            |
      +-------+-------+----+-------------------------------------------+
      |       | ODU1  |1-16|Flexible, != other existing LO ODU1s' TPNs |
      |       +-------+----+-------------------------------------------+
      |       | ODU2  |1-4 |Flexible, != other existing LO ODU2s' TPNs |
      | ODU3  +-------+----+-------------------------------------------+
      |       |ODU0 & |    |Flexible, != other existing LO ODU0s and   |
      |       |ODU2e &|1-32|ODU2s and ODUflexes' TPNs                  |
      |       |ODUflex|    |                                           |
      +-------+-------+----+-------------------------------------------+
      | ODU4  |Any ODU|1-80|Flexible, != ANY other existing LO ODUs'   |
      |       |       |    |TPNs                                       |
      +-------+-------+----+-------------------------------------------+

             Table 4: TPN Assignment Rules (1.25 Gbps TS Granularity)

      Note that in the case of "Flexible", the value of TPN MAY not
      correspond to the TS number as per [G709-2012].

   Length: 12 bits

      Indicates the number of bits of the Bit Map field, i.e., the total
      number of TSs in the HO ODUk link.  The TS granularity, 1.25 Gbps
      or 2.5 Gbps, may be derived by dividing the HO ODUk link's rate by
      the value of the Length field.  In the context of [G709-2012], the
      values of 4 and 16 indicate a TS granularity of 2.5 Gbps, and the
      values 2, 8, 32, and 80 indicate a TS granularity of 1.25 Gbps.

      In the case of an ODUk mapped into OTUk, there is no need to
      indicate which tributary slots will be used, so the Length field
      MUST be set to 0.

   Bit Map: variable

      Indicates which tributary slots in the HO ODUk that the LO ODUj
      will be multiplexed into.  The sequence of the Bit Map is
      consistent with the sequence of the tributary slots in the HO
      ODUk.  Each bit in the bit map represents the corresponding
      tributary slot in the HO ODUk with a value of 1 or 0 indicating
      whether the tributary slot will be used by the LO ODUj or not.

   Padding Bits

      Are added after the Bit Map to make the whole label a multiple of
      four bytes if necessary.  Padding bits MUST be set to 0 and MUST
      be ignored on receipt.

6.2.  Procedures

   The ingress node MUST generate a Path message and specify the OTN-TDM
   Switching Type and corresponding G-PID in the
   GENERALIZED_LABEL_REQUEST object, which MUST be processed as defined
   in [RFC3473].

   The ingress node of an LSP MAY include a Label ERO (Explicit Route
   Object) subobject to indicate the label in each hop along the path.
   Note that the TPN in the Label ERO subobject need not be assigned by
   the ingress node.  When the TPN is assigned by a node, the node MUST
   assign a valid TPN value and then put this value into the TPN field
   of the GENERALIZED_LABEL object when receiving a Path message.

   In order to create bidirectional LSP, the ingress node and upstream
   node MUST generate an UPSTREAM_LABEL object on the outgoing interface
   to indicate the reserved TSs of ODUk and the assigned TPN value in
   the upstream direction.  This UPSTREAM_LABEL object is sent to the
   downstream node via a Path massage for upstream resource reservation.

   The ingress node or upstream node MAY generate a LABEL_SET object to
   indicate which labels on the outgoing interface in the downstream
   direction are acceptable.  The downstream node will restrict its
   choice of labels, i.e., TS resource and TPN value, to one that is in
   the LABEL_SET object.

   The ingress node or upstream node MAY also generate a SUGGESTED_LABEL
   object to indicate the preference of TS resource and TPN value on the
   outgoing interface in the downstream direction.  The downstream node
   is not required to use the suggested labels; it may use another label
   based on local decision and send it to the upstream node, as
   described in [RFC3473].

   When an upstream node receives a Resv message containing a
   GENERALIZED_LABEL object with an OTN-TDM label, it MUST first
   identify which ODU Signal Type is multiplexed or mapped into which
   ODU Signal Type according to the Traffic Parameters and the IF_ID
   RSVP_HOP object in the received message.

   -  In the case of ODUj-to-ODUk multiplexing, the node MUST retrieve
      the reserved tributary slots in the ODUk by its downstream
      neighbor node according to the position of the bits that are set
      to 1 in the Bit Map field.  The node determines the TS granularity
      (according to the total TS number of the ODUk or pre-configured TS
      granularity), so that the node can multiplex the ODUj into the
      ODUk based on the TS granularity.  The node MUST also retrieve the
      TPN value assigned by its downstream neighbor node from the label
      and fill the TPN into the related MSI byte(s) in the OPUk overhead
      in the data plane, so that the downstream neighbor node can check
      whether the TPN received from the data plane is consistent with
      the Expected MSI (ExMSI) and determine whether there is any
      mismatch defect.

   -  In the case of ODUk-to-OTUk mapping, the size of the Bit Map field
      MUST be 0, and no additional procedure is needed.

   When a downstream node or egress node receives a Path message
   containing a GENERALIZED_LABEL_REQUEST object for setting up an ODUj
   LSP from its upstream neighbor node, the node MUST generate an OTN-
   TDM label according to the Signal Type of the requested LSP and the
   available resources (i.e., available tributary slots of ODUk) that
   will be reserved for the LSP and send the label to its upstream
   neighbor node.

   -  In the case of ODUj-to-ODUk multiplexing, the node MUST first
      determine the size of the Bit Map field according to the Signal
      Type and the tributary slot type of ODUk and then set the bits to
      1 in the Bit Map field corresponding to the reserved tributary
      slots.  The node MUST also assign a valid TPN, which MUST NOT
      collide with other TPN values used by existing LO ODU connections
      in the selected HO ODU link, and configure the Expected MSI
      (ExMSI) using this TPN.  Then, the assigned TPN MUST be filled
      into the label.

   -  In the case of ODUk-to-OTUk mapping, the TPN field MUST be set to
      0.  Bit Map information is not required and MUST NOT be included,
      so the Length field MUST be set to 0 as well.

6.2.1.  Notification on Label Error

   When an upstream node receives a Resv message containing a
   GENERALIZED_LABEL object with an OTN-TDM label, the node MUST verify
   if the label is acceptable.  If the label is not acceptable, the node
   MUST generate a ResvErr message with a "Routing problem/Unacceptable
   label value" indication.  Per [RFC3473], the generated ResvErr
   message MAY include an ACCEPTABLE_LABEL_SET object.  With the
   exception of label semantics, a downstream node processing a received
   ResvErr message and ACCEPTABLE_LABEL_SET object is not modified by
   this document.

   Similarly, when a downstream node receives a Path message containing
   an UPSTREAM_LABEL object with an OTN-TDM label, the node MUST verify
   if the label is acceptable.  If the label is not acceptable, the node
   MUST generate a PathErr message with a "Routing problem/Unacceptable
   label value" indication.  Per [RFC3473], the generated PathErr
   message MAY include an ACCEPTABLE_LABEL_SET object.  With the
   exception of label semantics, the upstream nodes processing a
   received PathErr message and ACCEPTABLE_LABEL_SET object are not
   modified by this document.

   A received label SHALL be considered unacceptable when one of the
   following cases occurs:

   -  The received label doesn't conform to local policy;

   -  An invalid value appears in the Length field;

   -  The selected link only supports 2.5 Gbps TS granularity while the
      Length field in the label along with ODUk Signal Type indicates
      the 1.25 Gbps TS granularity;

   -  The label includes an invalid TPN value that breaks the TPN
      assignment rules; and

   -  The indicated resources (i.e., the number of "1"s in the Bit Map
      field) are inconsistent with the Traffic Parameters.

6.3.  Supporting Virtual Concatenation and Multiplication

   Per [RFC6344], the Virtual Concatenation Groups (VCGs) can be created
   using the One LSP approach or the Multiple LSPs approach.

   In the case of the One LSP approach, the explicit ordered list of all
   labels MUST reflect the order of VCG members, which is similar to
   [RFC4328].  In the case of multiplexed virtually concatenated signals
   (NVC > 1), the first label MUST indicate the components of the first
   virtually concatenated signal; the second label MUST indicate the
   components of the second virtually concatenated signal; and so on.
   In the case of multiplication of multiplexed virtually concatenated
   signals (MT > 1), the first label MUST indicate the components of the
   first multiplexed virtually concatenated signal; the second label
   MUST indicate components of the second multiplexed virtually
   concatenated signal; and so on.

   Support for Virtual Concatenation of ODU1, ODU2, and ODU3 Signal
   Types, as defined by [RFC6344], is not modified by this document.
   Virtual Concatenation of other Signal Types is not supported by
   [G709-2012].

   Multiplier (MT) usage is as defined in [RFC6344] and [RFC4328].

6.4.  Examples

   The following examples are given in order to illustrate the label
   format described in Section 6.1 of this document.

   (1) ODUk-to-OTUk Mapping:

   In this scenario, the downstream node along an LSP returns a label
   indicating that the ODUk (k=1, 2, 3, 4) is directly mapped into the
   corresponding OTUk.  The following example label indicates an ODU1
   mapped into OTU1.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TPN = 0         |   Reserved    |     Length = 0        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   (2) ODUj-to-ODUk Multiplexing:

   In this scenario, this label indicates that an ODUj is multiplexed
   into several tributary slots of OPUk and then mapped into OTUk.  Some
   instances are shown as follows:

   -  ODU0-to-ODU2 Multiplexing:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TPN = 2         |   Reserved    |     Length = 8        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0 1 0 0 0 0 0 0|             Padding Bits (0)                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The label above indicates an ODU0 multiplexed into the second
   tributary slot of ODU2, wherein there are 8 TSs in ODU2 (i.e., the
   type of the tributary slot is 1.25 Gbps), and the TPN value is 2.

   -  ODU1-to-ODU2 Multiplexing with 1.25 Gbps TS Granularity:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TPN = 1         |   Reserved    |     Length = 8        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0 1 0 1 0 0 0 0|             Padding Bits (0)                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The label above indicates an ODU1 multiplexed into the 2nd and the
   4th tributary slots of ODU2, wherein there are 8 TSs in ODU2 (i.e.,
   the type of the tributary slot is 1.25 Gbps), and the TPN value is 1.

   -  ODU2 into ODU3 Multiplexing with 2.5 Gbps TS Granularity:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       TPN = 1         |   Reserved    |     Length = 16       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0 1 1 0 1 0 1 0 0 0 0 0 0 0 0 0|       Padding Bits (0)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The label above indicates an ODU2 multiplexed into the 2nd, 3rd, 5th,
   and 7th tributary slots of ODU3, wherein there are 16 TSs in ODU3
   (i.e., the type of the tributary slot is 2.5 Gbps), and the TPN value
   is 1.

7.  Supporting Hitless Adjustment of ODUflex(GFP)

   [G7044] describes the procedure of ODUflex(GFP) hitless resizing
   using the Link Connection Resize (LCR) and Bandwidth Resize (BWR)
   protocols in the OTN data plane.

   For the control plane, signaling messages are REQUIRED to initiate
   the adjustment procedure.  Sections 2.5 and 4.6.4 of [RFC3209]
   describe how the Shared Explicit (SE) style is used in the Traffic
   Engineering (TE) network for bandwidth increasing and decreasing,
   which is still applicable for triggering the ODUflex(GFP) adjustment
   procedure in the data plane.

   Note that the SE style MUST be used at the beginning when creating a
   resizable ODUflex connection (Signal Type = 21).  Otherwise an error
   with Error Code "Conflicting reservation style" MUST be generated
   when performing bandwidth adjustment.

   -  Bandwidth Increasing

      For the ingress node, in order to increase the bandwidth of an
      ODUflex(GFP) connection, a Path message with SE style (keeping
      Tunnel ID unchanged and assigning a new LSP ID) MUST be sent along
      the path.

      The ingress node will trigger the BWR protocol when successful
      completion of LCR protocols on every hop after the Resv message is
      processed.  On success of BWR, the ingress node SHOULD send a
      PathTear message to delete the old control state (i.e., the
      control state of the ODUflex(GFP) before resizing) on the control
      plane.

      A downstream node receiving a Path message with SE style compares
      the old Traffic Parameters (stored locally) with the new one
      carried in the Path message to determine the number of TSs to be
      added.  After choosing and reserving new available TS(s), the
      downstream node MUST send back a Resv message carrying both the
      old and new GENERALIZED_LABEL objects in the SE flow descriptor.

      An upstream neighbor receiving a Resv message with an SE flow
      descriptor MUST determine which TS(s) is/are added and trigger the
      LCR protocol between itself and its downstream neighbor node.

   -  Bandwidth Decreasing

      For the ingress node, a Path message with SE style SHOULD also be
      sent for decreasing the ODUflex bandwidth.

      The ingress node will trigger the BWR protocol when successful
      completion of LCR handshake on every hop after Resv message is
      processed.  On success of BWR, the second step of LCR, i.e., link
      connection decrease procedure will be started on every hop of the
      connection.  After decreasing the bandwidth, the ingress node
      SHOULD send a ResvErr message to tear down the old control state.

      A downstream node receiving a Path message with SE style compares
      the old Traffic Parameters with the new one carried in the Path
      message to determine the number of TSs to be decreased.  After
      choosing TSs to be decreased, the downstream node MUST send back a
      Resv message carrying both the old and new GENERALIZED_LABEL
      objects in the SE flow descriptor.

      An upstream neighbor receiving a Resv message with an SE flow
      descriptor MUST determine which TS(s) is/are decreased and trigger
      the first step of the LCR protocol (i.e., LCR handshake) between
      itself and its downstream neighbor node.

8.  Operations, Administration, and Maintenance (OAM) Considerations

   OTN OAM configuration could be done through either Network Management
   Systems (NMSs) or the GMPLS control plane as defined in [TDM-OAM].
   [RFC4783] SHOULD be used for communication of alarm information in
   GMPLS-based OTN.

   Management Information Bases (MIBs) may need be extended to read new
   information (e.g., OTN-TDM Generalized Label and OTN-TDM
   SENDER_TSPEC / FLOWSPEC) from the OTN devices.  This is outside the
   scope of this document.

   More information about the management aspects for GMPLS-based OTN,
   refer to Section 5.7 of [RFC7062].

9.  Control-Plane Backward-Compatibility Considerations

   As described in [RFC7062], since [RFC4328] has been deployed in the
   network for the nodes that support the 2001 revision of the G.709
   specification, control-plane backward compatibility SHOULD be taken
   into consideration.  More specifically:

   o  Nodes supporting this document SHOULD support [RFC7138].

   o  Nodes supporting this document MAY support [RFC4328] signaling.

   o  A node supporting both sets of procedures (i.e., [RFC4328] and
      this document) is not required to signal an LSP using both
      procedures, i.e., to act as a signaling version translator.

   o  Ingress nodes that support both sets of procedures MAY select
      which set of procedures to follow based on routing information or
      local policy.

   o  Per [RFC3473], nodes that do not support this document will
      generate a PathErr message, with a "Routing problem/Switching
      Type" indication.

10.  Security Considerations

   This document is a modification to [RFC3473] and [RFC4328]; it only
   differs in specific information communicated.  As such, this document
   introduces no new security considerations to the existing GMPLS
   signaling protocols.  Refer to [RFC3473] and [RFC4328] for further
   details of the specific security measures.  Additionally, [RFC5920]
   provides an overview of security vulnerabilities and protection
   mechanisms for the GMPLS control plane.

11.  IANA Considerations

   IANA has made the following assignments in the "Class Types or C-
   Types - 9 FLOWSPEC" and "Class Types or C-Types - 12 SENDER_TSPEC"
   section of the "Resource Reservation Protocol (RSVP) Parameters"
   registry located at
   <http://www.iana.org/assignments/rsvp-parameters>.

      Value     Description         Reference
      7         OTN-TDM            [RFC7139]

   IANA maintains the "Generalized Multi-Protocol Label Switching
   (GMPLS) Signaling Parameters" registry (see
   <http://www.iana.org/assignments/gmpls-sig-parameters>).  The
   "Generalized PIDs (G-PID)" subregistry is included in this registry,
   which is extended and updated by this document as detailed below.

      Value Type                            Technology      Reference
      ===== ======================          ==========      =========
      47    G.709 ODU-2.5G                  G.709 ODUk      [RFC4328]
            (IANA updated the Type field)                   [RFC7139]
      56    SBCON/ESCON                     G.709 ODUk,     [RFC4328]
            (IANA updated the Type field)   Lambda, Fiber   [RFC7139]
      59    Framed GFP                      G.709 ODUk      [RFC7139]
      60    STM-1                           G.709 ODUk      [RFC7139]
      61    STM-4                           G.709 ODUk      [RFC7139]
      62    InfiniBand                      G.709 ODUflex   [RFC7139]
      63    SDI (Serial Digital Interface)  G.709 ODUk      [RFC7139]
      64    SDI/1.001                       G.709 ODUk      [RFC7139]
      65    DVB_ASI                         G.709 ODUk      [RFC7139]
      66    G.709 ODU-1.25G                 G.709 ODUk      [RFC7139]
      67    G.709 ODU-any                   G.709 ODUk      [RFC7139]
      68    Null Test                       G.709 ODUk      [RFC7139]
      69    Random Test                     G.709 ODUk      [RFC7139]
      70    64B/66B GFP-F Ethernet          G.709 ODUk      [RFC7139]
   The new G-PIDs should be are shown in the TC MIB managed by IANA at
   https://www.iana.org/assignments/ianagmplstc-mib as follows:

      g709FramedGFP(59),
      g709STM1(60),
      g709STM4(61),
      g709InfiniBand(62),
      g709SDI(63),
      g709SDI1point001(64),
      g709DVBASI(65),
      g709ODU1point25G(66),
      g709ODUAny(67),
      g709NullTest(68),
      g709RandomTest(69),
      g709GFPFEthernet(70)

   Note that IANA must has not change changed the names of the objects in this MIB
   module with the values 47 and 56.

   IANA has defined an "OTN Signal Type" subregistry to the "Generalized
   Multi-Protocol Label Switching (GMPLS) Signaling Parameters"
   registry:

      Value    Signal Type                           Reference
      -----    -----------                           ---------
      0        Not significant                       [RFC4328]
      1        ODU1 (i.e., 2.5 Gbps)                 [RFC4328]
      2        ODU2 (i.e., 10 Gbps)                  [RFC4328]
      3        ODU3 (i.e., 40 Gbps)                  [RFC4328]
      4        ODU4 (i.e., 100 Gbps)                 [RFC7139]
      5        Unassigned                            [RFC4328]
      6        Och at 2.5 Gbps                       [RFC4328]
      7        OCh at 10 Gbps                        [RFC4328]
      8        OCh at 40 Gbps                        [RFC4328]
      9        OCh at 100 Gbps                       [RFC7139]
      10       ODU0 (i.e., 1.25 Gbps)                [RFC7139]
      11       ODU2e (i.e., 10 Gbps for FC1200       [RFC7139]
               and GE LAN)
      12-19    Unassigned                            [RFC7139]
      20       ODUflex(CBR) (i.e., 1.25*N Gbps)      [RFC7139]
      21       ODUflex(GFP-F), resizable             [RFC7139]
               (i.e., 1.25*N Gbps)
      22       ODUflex(GFP-F), non-resizable         [RFC7139]
               (i.e., 1.25*N Gbps)
      23-255   Unassigned                            [RFC7139]

   New values are to be assigned via Standards Action as defined in
   [RFC5226].

12.  References

12.1.  Normative References

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

   [RFC2205]   Braden, R., Ed., 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.

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

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

   [RFC4328]   Papadimitriou, D., Ed., "Generalized Multi-Protocol Label
               Switching (GMPLS) Signaling Extensions for G.709 Optical
               Transport Networks Control", RFC 4328, January 2006.

   [RFC4506]   Eisler, M., Ed., "XDR: External Data Representation
               Standard", STD 67, RFC 4506, May 2006.

   [RFC4783]   Berger, L., Ed., "GMPLS - Communication of Alarm
               Information", RFC 4783, December 2006.

   [RFC6344]   Bernstein, G., Ed., Caviglia, D., Rabbat, R., and H. van
               Helvoort, "Operating Virtual Concatenation (VCAT) and the
               Link Capacity Adjustment Scheme (LCAS) with Generalized
               Multi-Protocol Label Switching (GMPLS)", RFC 6344, August
               2011.

   [RFC7138]   Ceccarelli, D., Zhang, F., Belotti, S., Rao, R., and J.
               Drake, "Traffic Engineering Extensions to OSPF for GMPLS
               Control of Evolving G.709 OTN Optical Transport Networks",
               RFC 7138,
               February March 2014.

   [G709-2012] ITU-T, "Interfaces for the Optical Transport Network
               (OTN)", G.709/Y.1331 Recommendation, February 2012.

   [G7044]     ITU-T, "Hitless adjustment of ODUflex", G.7044/Y.1347,
               October 2011.

   [G7041]     ITU-T, "Generic framing procedure", G.7041/Y.1303, April
               2011.

   [IEEE]      "IEEE Standard for Binary Floating-Point Arithmetic",
               ANSI/IEEE Standard 754-1985, Institute of Electrical and
               Electronics Engineers, August 1985.

12.2.  Informative References

   [RFC5226]   Narten, T. and H. Alvestrand, "Guidelines for Writing an
               IANA Considerations Section in RFCs", BCP 26, RFC 5226,
               May 2008.

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

   [RFC7062]   Zhang, F., Ed., Li, D., Li, H., Belotti, S., and D.
               Ceccarelli, "Framework for GMPLS and PCE Control of G.709
               Optical Transport Networks", RFC 7062, November 2013.

   [RFC7096]  Belotti, S., Ed., Grandi, P., Ceccarelli, D., Ed.,
               Caviglia, D., Zhang, F., and D. Li, "Evaluation of
               Existing GMPLS Encoding against G.709v3 Optical Transport
               Networks (OTNs)", RFC 7096, January 2014.

   [TDM-OAM]   Kern, A., and A. Takacs, "GMPLS RSVP-TE Extensions for
               SONET/SDH and OTN OAM Configuration", Work in Progress,
               November 2013.

13. Contributors

   Yi Lin
   Huawei Technologies
   F3-5-B R&D Center, Huawei Base
   Bantian, Longgang District
   Shenzhen 518129
   P.R. China
   Phone: +86-755-28972914
   EMail: yi.lin@huawei.com
   Yunbin Xu
   China Academy of Telecommunication Research of MII
   11 Yue Tan Nan Jie
   Beijing
   P.R. China
   Phone: +86-10-68094134
   EMail: xuyunbin@mail.ritt.com.cn

   Pietro Grandi
   Alcatel-Lucent
   Optics CTO
   Via Trento 30 20059 Vimercate
   Milano
   Italy
   Phone: +39 039 6864930
   EMail: pietro_vittorio.grandi@alcatel-lucent.it

   Diego Caviglia
   Ericsson
   Via A. Negrone 1/A
   Genova - Sestri Ponente
   Italy
   EMail: diego.caviglia@ericsson.com

   Rajan Rao
   Infinera Corporation
   169, Java Drive
   Sunnyvale, CA 94089
   USA
   EMail: rrao@infinera.com

   John E Drake
   Juniper
   EMail: jdrake@juniper.net

   Igor Bryskin
   Adva Optical
   EMail: IBryskin@advaoptical.com

   Jonathan Sadler, Tellabs
   EMail: jonathan.sadler@tellabs.com

   Kam LAM, Alcatel-Lucent
   EMail: kam.lam@alcatel-lucent.com

   Francesco Fondelli, Ericsson
   EMail: francesco.fondelli@ericsson.com
   Lyndon Ong, Ciena
   EMail: lyong@ciena.com

   Biao Lu, infinera
   EMail: blu@infinera.com

14.  Acknowledgments

   The authors would like to thank Lou Berger, Deborah Brungard, and
   Xiaobing Zi for their useful comments regarding this document.

Authors' Addresses

   Fatai Zhang (editor)
   Huawei Technologies
   F3-5-B R&D Center, Huawei Base
   Bantian, Longgang District
   Shenzhen 518129
   P.R. China
   Phone: +86-755-28972912
   EMail: zhangfatai@huawei.com

   Guoying Zhang
   China Academy of Telecommunication Research of MII
   11 Yue Tan Nan Jie
   Beijing
   P.R. China
   Phone: +86-10-68094272
   EMail: zhangguoying@mail.ritt.com.cn

   Sergio Belotti
   Alcatel-Lucent
   Optics CTO
   Via Trento 30 20059 Vimercate
   Milano
   Italy
   Phone: +39 039 6863033
   EMail: sergio.belotti@alcatel-lucent.it

   Daniele Ceccarelli
   Ericsson
   Via A. Negrone 1/A
   Genova - Sestri Ponente
   Italy
   EMail: daniele.ceccarelli@ericsson.com

   Khuzema Pithewan
   Infinera Corporation
   169, Java Drive
   Sunnyvale, CA 94089
   USA
   EMail: kpithewan@infinera.com