Network Working Group                                   Fatai Zhang, Ed.
Internet Draft                                                    Huawei
Category: Standards Track                                  Guoying Zhang
                                                                    CATR
                                                          Sergio Belotti
                                                          Alcatel-Lucent
                                                           D. Ceccarelli
                                                                Ericsson
                                                        Khuzema Pithewan
                                                                Infinera
Expires: April 17, 2012                                 October 17, 2011


      Generalized Multi-Protocol Label Switching (GMPLS) Signaling
  Extensions for the evolving G.709 Optical Transport Networks Control


               draft-ietf-ccamp-gmpls-signaling-g709v3-00.txt


Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

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

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

   This Internet-Draft will expire on April 17, 2012.



Abstract

   Recent progress in ITU-T Recommendation G.709 standardization has
   introduced new ODU containers (ODU0, ODU4, ODU2e and ODUflex) and



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   enhanced Optical Transport Networking (OTN) flexibility. Several
   recent documents have proposed ways to modify GMPLS signaling
   protocols to support these new OTN features.

   It is important that a single solution is developed for use in GMPLS
   signaling and routing protocols. This solution must support ODUk
   multiplexing capabilities, address all of the new features, be
   acceptable to all equipment vendors, and be extensible considering
   continued OTN evolution.

   This document describes the extensions to the Generalized Multi-
   Protocol Label Switching (GMPLS) signaling to control the evolving
   Optical Transport Networks (OTN) addressing ODUk multiplexing and new
   features including ODU0, ODU4, ODU2e and ODUflex.



Conventions used in this document

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



Table of Contents

   1. Introduction .................................................. 3
   2. Terminology ................................................... 4
   3. GMPLS Extensions for the Evolving G.709 - Overview ............ 4
   4. Extensions for Traffic Parameters for the Evolving G.709 ...... 5
      4.1. Usage of ODUflex(CBR) Traffic Parameter .................. 6
      4.2. Example of ODUflex(CBR) Traffic Parameter ................ 7
   5. Generalized Label ............................................. 8
      5.1. New definition of ODU Generalized Label .................. 8
      5.2. Examples ................................................ 11
      5.3. Label Distribution Procedure ............................ 12
         5.3.1. Notification on Label Error ........................ 13
      5.4. Supporting Virtual Concatenation and Multiplication ..... 14
      5.5. Control Plane Backward Compatibility Considerations ..... 14
   6. Supporting Multiplexing Hierarchy ............................ 15
      6.1. ODU FA-LSP Creation ..................................... 17
   7. Security Considerations ...................................... 17
   8. IANA Considerations .......................................... 17
   9. References ................................................... 17
      9.1. Normative References .................................... 17
      9.2. Informative References .................................. 19


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   10. Contributors ............................................... 19
   11. Authors' Addresses ......................................... 20
   12. Acknowledgment ............................................. 22

1. Introduction

   Generalized Multi-Protocol Label Switching (GMPLS) [RFC3945] extends
   MPLS to include Layer-2 Switching (L2SC), Time-Division Multiplex
   (e.g., SONET/SDH, PDH, and ODU), Wavelength (OCh, Lambdas) Switching,
   and Spatial Switching (e.g., incoming port or fiber to outgoing port
   or fiber). [RFC3471] presents a functional description of the
   extensions to Multi-Protocol Label Switching (MPLS) signaling
   required to support Generalized MPLS.  RSVP-TE-specific formats and
   mechanisms and technology specific details are defined in [RFC3473].

   With the evolution and deployment of G.709 technology, it is
   necessary that appropriate enhanced control technology support be
   provided for G.709. [RFC4328] describes the control technology
   details that are specific to foundation G.709 Optical Transport
   Networks (OTN), as specified in the ITU-T Recommendation G.709 [G709-
   V1], for ODUk deployments without multiplexing.

   In addition to increasing need to support ODUk multiplexing, the
   evolution of OTN has introduced additional containers and new
   flexibility. For example, ODU0, ODU2e, ODU4 containers and ODUflex
   are developed in [G709-V3].

   In addition, the following issues require consideration:

      -  Support for hitless adjustment of ODUflex, which is to be
         specified in ITU-T G.hao.

      -  Support for Tributary Port Number. The Tributary Port Number
         has to be negotiated on each link for flexible assignment of
         tributary ports to tributary slots in case of LO-ODU over HO-
         ODU (e.g., ODU2 into ODU3).

   Therefore, it is clear that [RFC4328] has to be updated or superceded
   in order to support ODUk multiplexing, as well as other ODU
   enhancements introduced by evolution of OTN standards.

   This document updates [RFC4328] extending the G.709 ODUk traffic
   parameters and also presents a new OTN label format which is very
   flexible and scalable.





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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-V3]. The corresponding
   new signal types are summarized below:

      -  Optical Channel Transport Unit (OTUk):
         . OTU4

      -  Optical Channel Data Unit (ODUk):
         . ODU0
         . ODU2e
         . ODU4
         . ODUflex

   A new Tributary Slot (TS) granularity (i.e., 1.25 Gbps) is also
   described in [G709-V3]. Thus, there are now two TS granularities for
   the foundation OTN ODU1, ODU2 and ODU3 containers. The TS granularity
   at 2.5 Gbps is used on 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),
   the evolving OTN [G.709-V3] 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 [OTN-frwk].

   Virtual Concatenation (VCAT) of OPUk (OPUk-Xv, k = 1/2/3, X = 1...256)
   is also supported by [OTN-V3]. Note that VCAT of OPU0 / OPU2e / OPU4
   / OPUflex is not supported per [OTN-V3].

   [RFC4328] describes GMPLS signaling extensions to support the control
   for G.709 Optical Transport Networks (OTN) [G709-V1]. However,
   [RFC4328] needs to be updated because it 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 mode which assumes that the Tributary Port Number
   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 label format.


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   Additionally, procedures about Tributary Port Number assignment
   through control plane are also provided in this document.

4. Extensions for Traffic Parameters for the Evolving G.709

   The traffic parameters for G.709 are 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  |   Tolerance   |              NMC              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |              NVC              |        Multiplier (MT)        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                            Bit_Rate                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Signal Type needs to be extended in order to cover the new Signal
   Type introduced by the evolving OTN. The new Signal Type values are
   extended as follows:

      Value    Type
      -----    ----
      0        Not significant
      1        ODU1 (i.e., 2.5 Gbps)
      2        ODU2 (i.e., 10 Gbps)
      3        ODU3 (i.e., 40 Gbps)
      4        ODU4 (i.e., 100 Gbps)
      5        Reserved (for future use)
      6        OCh at 2.5 Gbps
      7        OCh at 10 Gbps
      8        OCh at 40 Gbps
      9        OCh at 100 Gbps
      10       ODU0 (i.e., 1.25 Gbps)
      11       ODU2e (i.e., 10Gbps 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)

   In case of ODUflex(CBR), the Bit_Rate and Tolerance fields MUST be
   used together to represent the actual bandwidth of ODUflex, where:



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   -  The Bit_Rate field indicates the nominal bit rate of ODUflex(CBR)
      expressed in bytes per second, encoded as a 32-bit IEEE single-
      precision floating-point number (referring to [RFC4506] and
      [IEEE]).

   -  The Tolerance field indicates the bit rate tolerance (part per
      million, ppm) of the ODUflex(CBR) encoded as an unsigned integer,
      which is bounded in 0~100ppm.

   For example, for an ODUflex(CBR) service with Bit_Rate = 2.5Gbps and
   Tolerance = 100ppm, the actual bandwidth of the ODUflex is:

                         2.5Gbps * (1 +/- 100ppm)

   In case of other ODUk signal types, the Bit_Rate and Tolerance fields
   are not necessary and MUST be set to 0.

   The usage of the NMC, NVC and Multiplier (MT) fields are the same as
   [RFC4328].

4.1. Usage of ODUflex(CBR) Traffic Parameter

   In case of ODUflex(CBR), the information of Bit_Rate and Tolerance in
   the ODUflex traffic parameter MUST be used to determine the total
   number of tributary slots N in the HO ODUk link to be reserved. Here:

         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)


   Therefore, a node receiving a PATH message containing ODUflex(CBR)
   traffic parameter can allocate precise number of tributary slots and
   set up the cross-connection for the ODUflex service.

   Table 1 below shows the actual bandwidth of the tributary slot of
   ODUk (in Gbps), referring to [G709-V3].

                   Table 1 - Actual TS bandwidth of ODUk

      ODUk       Minimum          Nominal          Maximum
      -------------------------------------------------------
      ODU2    1.249 384 632    1.249 409 620    1.249 434 608
      ODU3    1.254 678 635    1.254 703 729    1.254 728 823
      ODU4    1.301 683 217    1.301 709 251    1.301 735 285


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      Note that:

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


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

      Where: HO OPUk bit rate tolerance = 20ppm

   For different ODUk, the bandwidths of the tributary slot are
   different, and so the total number of tributary slots to be reserved
   for the ODUflex(CBR) may not be the same on different HO ODUk links.
   This is why the traffic parameter should bring the actual bandwidth
   information other than the NMC field.



4.2. Example of ODUflex(CBR) Traffic Parameter

   This section gives an example to illustrate the usage of ODUflex(CBR)
   traffic parameter.

   As shown in Figure 1, assume there is an ODUflex(CBR) service
   requesting a bandwidth of (2.5Gbps, +/-100ppm) from node A to node C.
   In other words, the ODUflex traffic parameter indicates that Signal
   Type is 33 (ODUflex(CBR)), Bit_Rate is 2.5Gbps and Tolerance is
   100ppm.

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

       =========: TS occupied by ODUflex
       ---------: free TS

            Figure 1 - Example of ODUflex(CBR) Traffic Parameter




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

      The maximum bandwidth of the ODUflex equals 2.5Gbps * (1 +
      100ppm), and the minimum bandwidth of the tributary slot of ODU4
      equals 1.301 683 217Gbps, so the total number of tributary slots
      N1 to be reserved on this link is:

      N1 = ceiling (2.5Gbps * (1 + 100ppm) / 1.301 683 217) = 2

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

      The maximum bandwidth of the ODUflex equals 2.5Gbps * (1 +
      100ppm), and the minimum bandwidth of the tributary slot of ODU2
      equals 1.249 384 632Gbps, so the total number of tributary slots
      N2 to be reserved on this link is:

      N2 = ceiling (2.5Gbps * (1 + 100ppm) / 1.249 384 632) = 3

5. Generalized Label

   [RFC3471] has defined the Generalized Label which extends the
   traditional label by allowing the representation of not only labels
   which are sent in-band with associated data packets, but also labels
   which identify time-slots, wavelengths, or space division multiplexed
   positions. The format of the corresponding RSVP-TE Generalized Label
   object is defined in the Section 2.3 of [RFC3473].

   However, for different technologies, we usually need use specific
   label rather than the Generalized Label. For example, the label
   format described in [RFC4606] could be used for SDH/SONET, the label
   format in [RFC4328] for G.709.



5.1. New definition of ODU Generalized Label

   In order to be compatible with new types of ODU signal and new types
   of tributary slot, the following new ODU label format MUST be used:

    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         .........                         ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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   The ODU Generalized Label 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 can be figured out locally according to the identifier of the
   selected interface carried in the IF_ID RSVP_HOP Object.

   TPN (12 bits): indicates the Tributary Port Number (TPN) for the
   assigned Tributary Slot(s).

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

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

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

   As per [G709-V3], The TPN is used to allow for correct demultiplexing
   in the data plane. When an LO ODUj is multiplexed into 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-V3], the TPN field MUST be set as according to the
   following tables:



          Table 2 - TPN Assignment Rules (2.5Gbps TS granularity)
   +-------+-------+----+----------------------------------------------+
   |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    |
   +-------+-------+----+----------------------------------------------+






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          Table 3 - TPN Assignment Rules (1.25Gbps 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|ODU2es and ODUflexes' TPNs                    |
   |       |ODUflex|    |                                              |
   +-------+-------+----+----------------------------------------------+
   | ODU4  |Any ODU|1~80|Flexible, != ANY other existing LO ODUs' TPNs |
   +-------+-------+----+----------------------------------------------+

   Note that in the case of "Flexible", the value of TPN is not
   corresponding to the TS number as per [G709-V3].

   Length (12 bits): indicates the number of bit of the Bit Map field,
   i.e., the total number of TS in the HO ODUk link.

   In 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 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 HO ODUk. Each
   bit in the bit map represents the corresponding tributary slot in HO
   ODUk with a value of 1 or 0 indicating whether the tributary slot
   will be used by LO ODUj or not.

   Padded bits are added behind the Bit Map to make the whole label a
   multiple of four bytes if necessary. Padded bit MUST be set to 0 and
   MUST be ignored.

   Note that the Length field in the label format can also be used to
   indicate the TS type of the HO ODUk (i.e., TS granularity at 1.25Gbps
   or 2.5Gbps) since the HO ODUk type can be known from IF_ID RSVP_HOP
   Object. In some cases when there is no LMP or routing to make the two


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   end points of the link to know the TSG, the TSG information used by
   another end can be deduced from the label format. For example, for HO
   ODU2 link, the value of the length filed will be 4 or 8, which
   indicates the TS granularity is 2.5Gbps or 1.25Gbps, respectively.

5.2. Examples

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

   (1) ODUk into OTUk mapping:

   In such conditions, 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 into ODUk multiplexing:

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

   -  ODU0 into 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|             Padded Bits (0)                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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

   -  ODU1 into ODU2 Multiplexing with 1.25Gbps TS granularity:





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

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

   -  ODU2 into ODU3 Multiplexing with 2.5Gbps 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|       Padded Bits (0)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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

5.3. Label Distribution Procedure

   This document does not change the existing label distribution
   procedures [RFC4328] for GMPLS except that the new ODUk label MUST be
   processed as follows.

   When a node receives a generalized label request for setting up an
   ODUj LSP from its upstream neighbor node, the node MUST generate an
   ODU label according to the signal type of the requested LSP and the
   free resources (i.e., free tributary slots of ODUk) that will be
   reserved for the LSP, and send the label to its upstream neighbor
   node.

   In case of ODUj to ODUk multiplexing, the node MUST firstly 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 does not collide with other TPN
   value used by existing LO ODU connections in the selected HO ODU link,
   and configure the expected multiplex structure identifier (ExMSI)
   using this TPN. Then, the assigned TPN is filled into the label.


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   In case of ODUk to OTUk mapping, the node only needs to fill the ODUj
   and the ODUk fields with corresponding values in the label. Other
   bits are reserved and MUST be set to 0.

   In order to process a received ODU label, the node MUST firstly learn
   which ODU signal type is multiplexed or mapped into which ODU signal
   type accordingly to the traffic parameters and the IF_ID RSVP_HOP
   Object in the received message.

   In 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 type (according to the total TS
   number of the ODUk, or pre-configured TS type), so that the node,
   based on the TS type, can multiplex the ODUj into the ODUk. 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 ExMSI and determine whether there is any mismatch
   defect.

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

   Note that the procedures of other label related objects (e.g.,
   Upstream Label, Label Set) are similar to the one described above.

   Note also that the TPN in the label_ERO MAY not be assigned (i.e.,
   TPN field = 0) if the TPN is requested to be assigned locally.

5.3.1. Notification on Label Error

   When receiving an ODUk label from the neighbor node, the node SHOULD
   check the integrity of the label. An error message containing an
   "Unacceptable label value" indication ([RFC3209]) SHOULD be sent if
   one of the following cases occurs:

   -  Invalid value in the length field.

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

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



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   -  The reserved resources (i.e., the number of "1" in the Bit Map
      field) do not match with the Traffic Parameters.

5.4. Supporting Virtual Concatenation and Multiplication

   As per [VCAT], the VCGs can be created using Co-Signaled style or
   Multiple LSPs style.

   In case of Co-Signaled style, the explicit ordered list of all labels
   reflects the order of VCG members, which is similar to [RFC4328]. In
   case of multiplexed virtually concatenated signals (NVC > 1), the
   first label indicates the components of the first virtually
   concatenated signal; the second label indicates the components of the
   second virtually concatenated signal; and so on. In case of
   multiplication of multiplexed virtually concatenated signals (MT > 1),
   the first label indicates the components of the first multiplexed
   virtually concatenated signal; the second label indicates components
   of the second multiplexed virtually concatenated signal; and so on.

   In case of Multiple LSPs style, multiple control plane LSPs are
   created with a single VCG and the VCAT Call can be used to associate
   the control plane LSPs. The procedures are similar to section 6 of
   [VCAT].



5.5. Control Plane Backward Compatibility Considerations

   Since the [RFC4328] has been deployed in the network for the nodes
   that support [G709-V1], we call nodes supporting [RFC4328] "legacy
   nodes". Backward compatibility SHOULD be taken into consideration
   when the new nodes (i.e., nodes that support RSVP-TE extensions
   defined in this document) and the legacy nodes are interworking.

   For backward compatibility consideration, the new node SHOULD have
   the ability to generate and parse legacy labels.

   o  A legacy node always generates and sends legacy label to its
      upstream node, no matter the upstream node is new or legacy, as
      described in [RFC4328].

   o  A new node SHOULD generate and send legacy labels if its upstream
      node is a legacy one, and generate and send new label if its
      upstream node is a new one.

   One backward compatibility example is shown in Figure 2:



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           Path          Path           Path           Path
   +-----+ ----> +-----+ ----> +------+ ----> +------+ ----> +-----+
   |     |       |     |       |      |       |      |       |     |
   |  A  +-------+  B  +-------+   C  +-------+   D  +-------+  E  |
   | new |       | new |       |legacy|       |legacy|       | new |
   +-----+ <---- +-----+ <---- +------+ <---- +------+ <---- +-----+
            Resv          Resv           Resv           Resv
        (new label)  (legacy label) (legacy label)  (legacy label)

                Figure 2 - Backwards compatibility example

   As described above, for backward compatibility considerations, it is
   necessary for a new node to know whether the neighbor node is new or
   legacy.

   One optional method is manual configuration, but it is recommended to
   use LMP to discover the capability of the neighbor node automatically,
   as described in [OTN-LMP].

   When performing the HO ODU link capability negotiation:

   o  If the neighbor node only support the 2.5Gbps TS and only support
      ODU1/ODU2/ODU3, the neighbor node SHOULD be treated as a legacy
      node.

   o  If the neighbor node can support the 1.25Gbps TS, or can support
      other LO ODU types defined in [G709-V3]), the neighbor node SHOULD
      be treated as new node.

   o  If the neighbor node returns a LinkSummaryNack message including
      an ERROR_CODE indicating nonsupport of HO ODU link capability
      negotiation, the neighbor node SHOULD be treated as a legacy node.



6. Supporting Multiplexing Hierarchy

   As described in [OTN-FRWK], one ODUj connection can be nested into
   another ODUk (j<k) connection, which forms the multiplexing hierarchy
   in the ODU layer. This is useful if there are some intermediate nodes
   in the network which only support ODUk but not ODUj switching.

   For example, in Figure 3, assume that N3 is a legacy node which only
   supports [G709-V1] and does not support ODU0 switching. If an ODU0
   connection between N1 and N5 is required, then we can create an ODU2
   connection between N2 and N4 (or ODU1 / ODU3 connection, depending on
   policies and the capabilities of the two ends of the connection), and


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   nest the ODU0 into the ODU2 connection. In this way, N3 only needs to
   perform ODU2 switching and does not need to be aware of the ODU0
   connection.

      |                                                          |
      |<------------------- ODU0 Connection -------------------->|
      |              |                            |              |
      |              |<---- ODU2 Connection ----->|              |
      |              |                            |              |
   +----+         +----+         +----+         +----+         +----+
   | N1 +---------+ N2 +=========+ N3 +=========+ N4 +---------+ N5 |
   +----+         +----+         +----+         +----+         +----+
         ODU3 link      ODU3 link      ODU3 link      ODU3 link

               Figure 3 - Example of multiplexing hierarchy

   The control plane signaling should support the provisioning of
   hierarchical multiplexing. Two methods are provided below (taking
   Figure 3 as example):

   -  Using the multi-layer network signaling described in [RFC4206],
      [RFC6107] and [RFC6001] (including related modifications, if
      needed). That is, when the signaling message for ODUO connection
      arrives at N2, a new RSVP session between N2 and N4 is triggered
      to create the ODU2 connection. This ODU2 connection is treated as
      a Forwarding Adjacency (FA) after it is created. And then the
      signaling procedure for the ODU0 connection can be continued using
      the resource of the ODU2 FA.

   -  The ODU2 FA-LSP is created in advance based on network planning,
      which is treated as an FA. Then the ODU0 connection can be created
      using the resource of the ODU2 FA. In this case, the ODU2 FA-LSP
      and inner ODU0 connections are created separately.

   For both methods, when creating an FA-LSP(e.g., ODU2 FA-LSP), the
   penultimate hop needs to choose a correct outgoing interface for the
   ODU2 connection, so that the destination node can support
   multiplexing and de-multiplexing LO ODU signal(e.g., ODU0). In order
   to choose a correct outgoing interface for the penultimate hop of the
   FA-LSP, multiplexing capability (i.e., what client signal type that
   can be adapted directly to this FA-LSP) should be carried in the
   signaling to setup this FA-LSP. In addition, when Auto_Negotiation in
   the data plane is not enabled, TS granularity may also be needed.






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6.1. ODU FA-LSP Creation

   The required hierarchies and TS type for both ends of an FA-LSP is
   for further study.



7. Security Considerations

   This document introduces no new security considerations to the
   existing GMPLS signaling protocols. Referring to [RFC3473], further
   details of the specific security measures are provided. Additionally,
   [GMPLS-SEC] provides an overview of security vulnerabilities and
   protection mechanisms for the GMPLS control plane.



8. IANA Considerations

   -  G.709 SENDER_TSPEC and FLOWSPEC objects:

       The traffic parameters, which are carried in the G.709
       SENDER_TSPEC and FLOWSPEC objects, do not require any new object
       class and type based on [RFC4328]:

       o  G.709 SENDER_TSPEC Object: Class = 12, C-Type = 5 [RFC4328]

       o  G.709 FLOWSPEC Object: Class = 9, C-Type = 5 [RFC4328]

   -  Generalized Label Object:

       The new defined ODU label (Section 5) is a kind of generalized
       label. Therefore, the Class-Num and C-Type of the ODU label is
       the same as that of generalized label described in [RFC3473],
       i.e., Class-Num = 16, C-Type = 2.



9. References

9.1. Normative References

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





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

   [RFC3209] D. Awduche et al, "RSVP-TE: Extensions to RSVP for LSP
             Tunnels", RFC3209, December 2001.

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

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

   [RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching
             (GMPLS) Architecture", RFC 3945, October 2004.

   [VCAT]    G. Bernstein et al, "Operating Virtual Concatenation (VCAT)
             and the Link Capacity Adjustment Scheme (LCAS) with
             Generalized Multi-Protocol Label Switching (GMPLS)", draft-
             ietf-ccamp-gmpls-vcat-lcas-13.txt, May 4, 2011.

   [RFC4206] K. Kompella, Y. Rekhter, Ed., " Label Switched Paths (LSP)
             Hierarchy with Generalized Multi-Protocol Label Switching
             (GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.

   [RFC6107] K. Shiomoto, A. Farrel, "Procedures for Dynamically
             Signaled Hierarchical Label Switched Paths", RFC6107,
             February 2011.

   [RFC6001] Dimitri Papadimitriou et al, "Generalized Multi-Protocol
             Label Switching (GMPLS) Protocol Extensions for Multi-Layer
             and Multi-Region Networks (MLN/MRN)", RFC6001, February 21,
             2010.

   [OTN-frwk] Fatai Zhang et al, "Framework for GMPLS and PCE Control of
             G.709 Optical Transport Networks", draft-ietf-ccamp-gmpls-
             g709-framework-04.txt, March 11, 2011.

   [OTN-info] S. Belotti et al, "Information model for G.709 Optical
             Transport Networks (OTN)", draft-ietf-ccamp-otn-g709-info-
             model-00.txt, April 18, 2011.

   [OTN-LMP] Fatai Zhang, Ed., "Link Management Protocol (LMP)
             extensions for G.709 Optical Transport Networks", draft-
             zhang-ccamp-gmpls-g.709-lmp-discovery-04.txt, April 6, 2011.


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   [G709-V3] ITU-T, "Interfaces for the Optical Transport Network (OTN)
             ", G.709/Y.1331, December 2009.

9.2. Informative References

   [G709-V1] ITU-T, "Interface for the Optical Transport Network (OTN),"
             G.709 Recommendation (and Amendment 1), February 2001
             (November 2001).

   [G709-V2] ITU-T, "Interface for the Optical Transport Network (OTN),"
             G.709 Recommendation, March 2003.

   [G798-V2] ITU-T, "Characteristics of optical transport network
             hierarchy equipment functional blocks", G.798, December
             2006.

   [G798-V3] ITU-T, "Characteristics of optical transport network
             hierarchy equipment functional blocks", G.798v3, consented
             June 2010.

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

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

   [GMPLS-SEC] Fang, L., Ed., "Security Framework for MPLS and GMPLS
             Networks", Work in Progress, October 2009.



10. Contributors

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


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


   Xiaobing Zi, Huawei Technologies
   Email: zixiaobing@huawei.com



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   Francesco Fondelli, Ericsson
   Email: francesco.fondelli@ericsson.com

   Lyndon Ong, Ciena
   Email: lyong@ciena.com

   Biao Lu, infinera
   Email: blu@infinera.com



11. 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
   +39 039 6863033
   Email: sergio.belotti@alcatel-lucent.it


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


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   Italy
   Email: daniele.ceccarelli@ericsson.com


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


   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
   +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


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   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


12. Acknowledgment

   The authors would like to thank Lou Berger and Deborah Brungard for
   their useful comments to the document.



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