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Versions: (draft-ceccarelli-ccamp-gmpls-ospf-g709) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 RFC 7138

CCAMP Working Group                                   D. Ceccarelli, Ed.
Internet-Draft                                                  Ericsson
Intended status: Standards Track                                F. Zhang
Expires: June 14, 2014                               Huawei Technologies
                                                              S. Belotti
                                                          Alcatel-Lucent
                                                                  R. Rao
                                                    Infinera Corporation
                                                                J. Drake
                                                                 Juniper
                                                       December 11, 2013


  Traffic Engineering Extensions to OSPF for Generalized MPLS (GMPLS)
                 Control of Evolving G.709 OTN Networks
                 draft-ietf-ccamp-gmpls-ospf-g709v3-13

Abstract

   This document describes Open Shortest Path First - Traffic
   Engineering (OSPF-TE) routing protocol extensions to support
   Generalized MPLS (GMPLS) control of Optical Transport Networks (OTN)
   specified in ITU-T Recommendation G.709 as published in 2012.  It
   extends mechanisms defined in RFC4203.

Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on June 14, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal



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   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  OSPF-TE Extensions . . . . . . . . . . . . . . . . . . . . . .  3
   3.  TE-Link Representation . . . . . . . . . . . . . . . . . . . .  5
   4.  ISCD format extensions . . . . . . . . . . . . . . . . . . . .  5
     4.1.  Switching Capability Specific Information  . . . . . . . .  7
       4.1.1.  Switching Capability Specific Information for
               fixed containers . . . . . . . . . . . . . . . . . . .  8
       4.1.2.  Switching Capability Specific Information for
               variable containers  . . . . . . . . . . . . . . . . .  8
       4.1.3.  Switching Capability Specific Information - Field
               values and explanation . . . . . . . . . . . . . . . .  9
   5.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     5.1.  MAX LSP Bandwidth fields in the ISCD . . . . . . . . . . . 12
     5.2.  Example of T,S and TS granularity utilization  . . . . . . 14
       5.2.1.  Example of different TS Granularities  . . . . . . . . 15
     5.3.  Example of ODUflex advertisement . . . . . . . . . . . . . 18
     5.4.  Example of single stage muxing . . . . . . . . . . . . . . 20
     5.5.  Example of multi stage muxing - Unbundled link . . . . . . 22
     5.6.  Example of multi stage muxing - Bundled links  . . . . . . 24
     5.7.  Example of component links with non-homogeneous
           hierarchies  . . . . . . . . . . . . . . . . . . . . . . . 25
   6.  OSPFv2 scalability . . . . . . . . . . . . . . . . . . . . . . 28
   7.  Compatibility  . . . . . . . . . . . . . . . . . . . . . . . . 29
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 29
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 29
     9.1.  Switching types  . . . . . . . . . . . . . . . . . . . . . 30
     9.2.  New sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . 30
   10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 31
   11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 33
   12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 33
     12.1. Normative References . . . . . . . . . . . . . . . . . . . 33
     12.2. Informative References . . . . . . . . . . . . . . . . . . 34
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35





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1.  Introduction

   G.709 Optical Transport Network (OTN) [G.709-2012] includes new fixed
   and flexible ODU (Optical channel Data Unit) containers, two types of
   Tributary Slots (i.e., 1.25Gbps and 2.5Gbps), and supports various
   multiplexing relationships (e.g., ODUj multiplexed into ODUk (j<k)),
   two different tributary slots for ODUk (K=1, 2, 3) and ODUflex
   service type.  In order to present this information in routing, this
   document provides OTN technology specific encoding for use in GMPLS
   OSPF-TE as defined in [RFC4203].

   For a short overview of OTN evolution and implications of OTN
   requirements on GMPLS routing please refer to [OTN-FWK].  The
   information model and an evaluation against the current solution are
   provided in [OTN-INFO].  The reader is supposed to be familiar with
   both of these documents.

   Routing information for Optical Channel Layer (OCh) (i.e.,
   wavelength) is beyond the scope of this document.  Please refer to
   [RFC6163] and [RFC6566] for further information.

1.1.  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].


2.  OSPF-TE Extensions

   In terms of GMPLS based OTN networks, each OTUk can be viewed as a
   component link, and each component link can carry one or more types
   of ODUj (j<k).

   Each TE Link State Advertisement (LSA) can carry a top-level link
   Type Length Value (TLV) with several nested sub-TLVs to describe
   different attributes of a TE link.  Two top-level TLVs are defined in
   [RFC3630]. (1) The Router Address TLV (referred to as the Node TLV)
   and (2) the TE link TLV.  One or more sub-TLVs can be nested into the
   two top-level TLVs.  The sub-TLV set for the two top-level TLVs are
   also defined in [RFC3630] and [RFC4203].

   As discussed in [OTN-FWK] and [OTN-INFO], OSPF-TE must be extended to
   be able to advertise the termination and switching capabilities of
   each different ODUj and ODUk/OTUk (Optical Transport Unit) and the
   advertisement of related multiplexing capabilities.  These
   capabilities are carried in the Interface Switching Capability
   Descriptor (ISCD) Switching Capability-specific information field



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   using formats defined in this document.  As discussed in [SWCAP-
   UPDT], the use of a technology specific Switching Capability-specific
   information field necessitates the definition of a new Switching
   Capability value and associated new Switching Capability.

   In the following, we will use ODUj to indicate a service type that is
   multiplexed into a higher order ODU, ODUk to indicate a higher order
   ODU including an ODUj and ODUk/OTUk to indicate the layer mapped into
   the OTUk.  Moreover, ODUj(S) and ODUk(S) are used to indicate ODUj
   and ODUk supporting switching capability only, and the ODUj->ODUk
   format is used to indicate the ODUj into ODUk multiplexing
   capability.

   This notation can be repeated as needed depending on the number of
   multiplexing levels.  In the following, the term "multiplexing tree"
   is used to identify a multiplexing hierarchy where the root is always
   a server ODUk/OTUk and any other supported multiplexed container is
   represented with increasing granularity until reaching the leaf of
   the tree.  The tree can be structured with more than one branch if
   the server ODUk/OTUk supports more than one hierarchy.

   For example, if a multiplexing hierarchy like the following one is
   considered:



             ODU2 ODU0    ODUflex ODU0
                \ /            \ /
                 |              |
               ODU3           ODU2
                  \            /
                   \          /
                    \        /
                     \      /
                       ODU4


   The ODU4 is the root of the muxing tree, ODU3 and ODU2 are containers
   directly multiplexed into the server and then ODU2, ODU0 are the
   leaves of the ODU3 branch, while ODUflex and ODU0 are the leaves of
   the ODU2 one.  This means that it is possible to have the following
   multiplexing capabilities:


           ODU2->ODU3->ODU4
           ODU0->ODU3->ODU4
           ODUflex->ODU2->ODU4
           ODU0->ODU2->ODU4



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3.  TE-Link Representation

   G.709 ODUk/OTUk Links are represented as TE-Links in GMPLS Traffic
   Engineering Topology for supporting ODUj layer switching.  These TE-
   Links can be modeled in multiple ways.

   OTUk physical Link(s) can be modeled as a TE-Link(s).  Figure 1 below
   provides an illustration of one hop OTUk TE-links.


           +-------+               +-------+               +-------+
           |  OTN  |               |  OTN  |               |  OTN  |
           |Switch |<- OTUk Link ->|Switch |<- OTUk Link ->|Switch |
           |   A   |               |   B   |               |   C   |
           +-------+               +-------+               +-------+

                   |<-- TE-Link -->|       |<-- TE-Link -->|


                          Figure 1: OTUk TE-Links

   It is possible to create TE-Links that span more than one hop by
   creating FAs between non-adjacent nodes (see Figure 2).  As in the
   one hop case, multiple hop TE-links advertise ODU switching capacity.


           +-------+               +-------+               +-------+
           |  OTN  |               |  OTN  |               |  OTN  |
           |Switch |<- OTUk Link ->|Switch |<- OTUk Link ->|Switch |
           |   A   |               |   B   |               |   C   |
           +-------+               +-------+               +-------+
                                 ODUk Switched

                   |<------------- ODUk Link ------------->|
                   |<-------------- TE-Link--------------->|


                      Figure 2: Multiple hop TE-Link


4.  ISCD format extensions

   The ISCD describes the switching capability of an interface and is
   defined in [RFC4203].  This document defines a new Switching
   Capability value for OTN [G.709-2012] as follows:


   Value                       Type



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   -----                       ----
   110 (TBA by IANA)           OTN-TDM capable (OTN-TDM)


   When supporting the extensions defined in this document, for both
   fixed and flexible ODUs, the Switching Capability and Encoding values
   MUST be used as follows:


   - Switching Capability = OTN-TDM
   - Encoding Type = G.709 ODUk (Digital Path) as defined in [RFC4328]


   The same switching type and encoding values must be used for both
   fixed and flexible ODUs.  When Switching Capability and Encoding
   fields are set to values as stated above, the Interface Switching
   Capability Descriptor MUST be interpreted as defined in [RFC4203].

   Maximum LSP Bandwidth

   The MAX LSP Bandwidth field is used according to [RFC4203]: i.e., 0
   <= MAX LSP Bandwidth <= ODUk/OTUk, and intermediate values are those
   on the branch of OTN switching hierarchy supported by the interface.
   For example, in the OTU4 link it could be possible to have ODU4 as
   MAX LSP Bandwidth for some priorities, ODU3 for others, ODU2 for some
   others, etc.  The bandwidth unit is in bytes per second and the
   encoding MUST be in Institute of Electrical and Electronic Engineers
   (IEEE) floating point format.  The discrete values for various ODUs
   are shown in the table below (please note that there are 1000 bits in
   a kbit according to normal practices in telecommunications).





















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+---------------------+------------------------------+-----------------+
|     ODU Type        |    ODU nominal bit rate      |Value in Byte/Sec|
|                     |                              |(floating p. val)|
+---------------------+------------------------------+-----------------+
|       ODU0          |      1,244,160 kbit/s        |    0x4D1450C0   |
|       ODU1          | 239/238 x 2,488,320 kbit/s   |    0x4D94F048   |
|       ODU2          | 239/237 x 9,953,280 kbit/s   |    0x4E959129   |
|       ODU3          | 239/236 x 39,813,120 kbit/s  |    0x4F963367   |
|       ODU4          | 239/227 x 99,532,800 kbit/s  |    0x504331E3   |
|       ODU2e         | 239/237 x 10,312,500 kbit/s  |    0x4E9AF70A   |
|                     |                              |                 |
|  ODUflex for CBR    |    239/238 x client signal   |     MAX LSP     |
|  Client signals     |           bit rate           |    BANDWIDTH    |
|                     |                              |                 |
| ODUflex for GFP-F   |                              |     MAX LSP     |
|Mapped client signal |      Configured bit rate     |    BANDWIDTH    |
|                     |                              |                 |
|                     |                              |                 |
|ODU flex resizable   |      Configured bit rate     |     MAX LSP     |
|                     |                              |    BANDWIDTH    |
+---------------------+------------------------------+-----------------+


   A single ISCD MAY be used for the advertisement of unbundled or
   bundled links supporting homogeneous multiplexing hierarchies and the
   same TS (Tributary Slot) granularity.  A different ISCD MUST be used
   for each different muxing hierarchy (muxing tree in the following
   examples) and different TS granularity supported within the TE Link.

   When a received LSA includes a sub-TLV not formatted accordingly to
   the precise specifications in this document, the problem SHOULD be
   logged and the wrongly formatted sub-TLV MUST NOT be used for path
   computation.

4.1.  Switching Capability Specific Information

   The technology specific part of the OTN-TDM ISCD may include a
   variable number of sub-TLVs called Bandwidth sub-TLVs.  Each sub-TLV
   is encoded with the sub-TLV header as defined in [RFC3630] section
   2.3.2.  The muxing hierarchy tree MUST be encoded as an order
   independent list.  Two types of Bandwidth sub-TLV are defined (TBA by
   IANA).  Note that type values are defined in this document and not in
   [RFC3630].

      - Type 1 - Unreserved Bandwidth for fixed containers

      - Type 2 - Unreserved/MAX LSP Bandwidth for flexible containers




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   The Switching Capability-Specific Information (SCSI) MUST include one
   Type 1 sub-TLV for each fixed container and one Type 2 sub-TLV for
   each variable container.  Each container type is identified by a
   Signal Type.  Signal Type values are defined in [OTN-SIG].

   With respect to ODUflex, three different signal types are allowed: 20
   - ODUflex Constant Bit Rate (CBR), 21 - ODUflex Generic Framing
   Procedure-Frame mapped (GFP-F) resizable and 22 - ODUflex (GFP-F)
   non-resizable.  Each MUST always be advertised in separate Type 2
   sub-TLVs as each uses different adaptation functions [G.805].  In the
   case that both GFP-F resizable and non-resizable (i.e., 21 and 22)
   are supported, only Signal Type 21 SHALL be advertised as this type
   also implies support for type 22 adaptation.

4.1.1.  Switching Capability Specific Information for fixed containers

   The format of the Bandwidth sub-TLV for fixed containers is depicted
   in the following figure:


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Signal type  | Num of stages |T|S| TSG | Res |    Priority   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Stage#1    |      ...      |   Stage#N     |    Padding    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Unreserved ODUj at Prio 0    |             .....             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Unreserved ODUj at Prio 7    |     Unreserved Padding        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



                  Figure 3: Bandwidth sub-TLV - Type 1 -

   The values of the fields shown in figure 3 are explained in section
   4.1.3.

4.1.2.  Switching Capability Specific Information for variable
        containers

   The format of the Bandwidth sub-TLV for variable containers is
   depicted in the following figure:





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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Type = 2 (Unres/MAX-var)   |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Signal type  | Num of stages |T|S| TSG | Res |    Priority   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Stage#1    |      ...      |   Stage#N     |    Padding    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                Unreserved Bandwidth at priority 0             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                Unreserved Bandwidth at priority 7             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP Bandwidth at priority 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP Bandwidth at priority 7               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                  Figure 4: Bandwidth sub-TLV - Type 2 -

   The values of the fields shown in figure 4 are explained in section
   4.1.3.

4.1.3.  Switching Capability Specific Information - Field values and
        explanation

   The fields in the Bandwidth sub-TLV MUST be filled as follows:

      - Signal Type (8 bits): Indicates the ODU type being advertised.
      Values are defined in [OTN-SIG].

      - Number of stages (8 bits): This field indicates the number of
      multiplexing stages used to transport the indicated signal type.
      It MUST be set to the number of stages represented in the sub-TLV.

      - Flags (8 bits):

         - T Flag (bit 17): Indicates whether the advertised bandwidth
         can be terminated.  When the signal type can be terminated T
         MUST be set, while when the signal type cannot be terminated T
         MUST be cleared.





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         - S Flag (bit 18): Indicates whether the advertised bandwidth
         can be switched.  When the signal type can be switched S MUST
         be set, while when the signal type cannot be switched S MUST be
         cleared.

         The value 0 in both T and S bits MUST NOT be used.

      - TS Granularity: Tributary Slot Granularity (3 bits): Used for
      the advertisement of the supported Tributary Slot granularity.
      The following values MUST be used:

         - 0 - Ignored

         - 1 - 1.25Gbps/2.5Gbps

         - 2 - 2.5Gbps only

         - 3 - 1.25Gbps only

         - 4-7 - Reserved

      A value of 1 MUST be used on interfaces which are configured to
      support the fall back procedures defined in [G.798-a2].  A value
      of 2 MUST be used on interfaces that only support 2.5Gbps time
      slots, such as [RFC4328] interfaces.  A value of 3 MUST be used on
      interfaces that are configured to only support 1.25Gbps time
      slots.  A value of 0 MUST be used for non-multiplexed signal types
      (i.e., a non-OTN client).

      - Res (3 bits): reserved bits.  MUST be set to 0 and ignored on
      receipt.

      - Priority (8 bits): A bitmap used to indicate which priorities
      are being advertised.  The bitmap is in ascending order, with the
      leftmost bit representing priority level 0 (i.e., the highest) and
      the rightmost bit representing priority level 7 (i.e., the
      lowest).  A bit MUST be set (1) corresponding to each priority
      represented in the sub-TLV, and MUST NOT be set (0) when the
      corresponding priority is not represented.  At least one priority
      level MUST be advertised that, unless overridden by local policy,
      SHALL be at priority level 0.

      - Stage (8 bits): Each Stage field indicates a signal type in the
      multiplexing hierarchy used to transport the signal indicated in
      the Signal Type field.  The number of Stage fields included in a
      sub-TLV MUST equal the value of the Number of Stages field.  The
      Stage fields MUST be ordered to match the data plane in ascending
      order (from the lowest order ODU to the highest order ODU).  The



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      values of the Stage field are the same as those defined for the
      Signal Type field.  When the Number of stage field carries a 0,
      then the Stage and Padding fields MUST be omitted.

      - Padding (variable): The Padding field is used to ensure the 32
      bit alignment of stage fields.  The length of the Padding field is
      always a multiple of 8 bits (1 byte).  Its length can be
      calculated, in bytes, as: 4 - ( "value of Number of Stages field"
      % 4).  The Padding field MUST be set to a zero (0) value on
      transmission and MUST be ignored on receipt.

      - Unreserved ODUj (16 bits): This field indicates the Unreserved
      Bandwidth at a particular priority level.  This field MUST be set
      to the number of ODUs at the indicated the Signal Type for a
      particular priority level.  One field MUST be present for each bit
      set in the Priority field, and is ordered to match the Priority
      field.  Fields MUST NOT be present for priority levels that are
      not indicated in the Priority field.

      - Unreserved Padding (16 bits): The Padding field is used to
      ensure the 32 bit alignment of Unreserved ODUj fields.  When
      present the Unreserved Padding field is 16 bits (2 byte) long.
      When the number of priorities is odd, the Unreserved Padding field
      MUST be included.  When the number of priorities is even, the
      Unreserved Padding MUST be omitted.

      - Unreserved Bandwidth (32 bits): This field indicates the
      Unreserved Bandwidth at a particular priority level.  This field
      MUST be set to the bandwidth, in Bytes/sec in IEEE floating point
      format, available at the indicated Signal Type for a particular
      priority level.  One field MUST be present for each bit set in the
      Priority field, and is ordered to match the Priority field.
      Fields MUST NOT be present for priority levels that are not
      indicated in the Priority field.

      - Maximum LSP Bandwidth (32 bit): This field indicates the maximum
      bandwidth that can be allocated for a single LSP at a particular
      priority level.  This field MUST be set to the maximum bandwidth,
      in Bytes/sec in IEEE floating point format, available to a single
      LSP at the indicated Signal Type for a particular priority level.
      One field MUST be present for each bit set in the Priority field,
      and is ordered to match the Priority field.  Fields MUST NOT be
      present for priority levels that are not indicated in the Priority
      field.  The advertisement of the MAX LSP Bandwidth MUST take into
      account HO OPUk bit rate tolerance and be calculated according to
      the following formula:





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         Max LSP BW = (# available TSs) * (ODTUk.ts nominal bit rate) *
         (1-HO OPUk bit rate tolerance)


5.  Examples

   The examples in the following pages are not normative and are not
   intended to imply or mandate any specific implementation.

5.1.  MAX LSP Bandwidth fields in the ISCD

   This example shows how the MAX LSP Bandwidth fields of the ISCD are
   filled accordingly to the evolving of the TE-link bandwidth
   occupancy.  In the example an OTU4 link is considered, with supported
   priorities 0,2,4,7 and muxing hierarchy ODU1->ODU2->ODU3->ODU4.

   At time T0, with the link completely free, the advertisement would
   be:


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SwCap=OTN_TDM | Encoding = 12 |    Reserved (all zeros)       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 0 = 100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 1 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 2 = 100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 3 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 4 = 100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 5 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 6 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 7 = 100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Switching Capability Specific Information         |
   |                        (variable length)                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     Figure 5: Example 1 - MAX LSP Bandwidth fields in the ISCD at T0




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   At time T1, an ODU3 at priority 2 is set-up, so for priority 0 the
   MAX LSP Bandwidth is still equal to the ODU4 bandwidth, while for
   priorities from 2 to 7 (excluding the non-supported ones) the MAX LSP
   Bandwidth is equal to ODU3, as no more ODU4s are available and the
   next supported ODUj in the hierarchy is ODU3.  The advertisement is
   updated 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SwCap=OTN_TDM | Encoding = 12 |    Reserved (all zeros)       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 0 = 100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 1 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 2 = 40Gbps          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 3 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 4 = 40Gbps          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 5 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 6 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 7 = 40Gbps          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Switching Capability Specific Information         |
   |                        (variable length)                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     Figure 6: Example 1 - MAX LSP Bandwidth fields in the ISCD  at T1

   At time T2, an ODU2 at priority 4 is set-up.  The first ODU3 is no
   longer available since T1, as it was kept by the ODU3 LSP, while the
   second is no more available and just 3 ODU2 are left in it.  ODU2 is
   now the MAX LSP Bandwidth for priorities higher than 4.  The
   advertisement is updated as follows:










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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SwCap=OTN_TDM | Encoding = 12 |    Reserved (all zeros)       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 0 = 100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 1 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 2 = 40Gbps          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 3 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 4 = 10Gbps          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 5 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 6 = 0               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             MAX LSP Bandwidth at priority 7 = 10Gbps          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Switching Capability Specific Information         |
   |                        (variable length)                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     Figure 7: Example 1 - MAX LSP Bandwidth fields in the ISCD at T2

5.2.  Example of T,S and TS granularity utilization

   In this example, an interface with Tributary Slot Type 1.25Gbps and
   fallback procedure enabled is considered (TS granularity=1).  It
   supports the simple ODU1->ODU2->ODU3 hierarchy and priorities 0 and
   3.  Suppose that in this interface the ODU3 signal type can be both
   switched or terminated, the ODU2 can only be terminated, and the ODU1
   switched only.  Please note that since the ODU1 is not being
   advertised to support ODU0, the value of is "ignored" (TS
   granularity=0).  For the advertisement of the capabilities of such
   interface, a single ISCD is used and its format is as follows:












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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU1  |  #stages= 2   |0|1|  0  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU2  | Stage#2=ODU3  |       Padding (all zeros)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU1 at Prio 0      |     Unres ODU1 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 1   |1|0|  1  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  |        Padding (all zeros)                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU2 at Prio 0      |     Unres ODU2 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU3  |  #stages= 0   |1|1|  1  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU3 at Prio 0      |     Unres ODU3 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


         Figure 8: Example 2 - TS granularity, T and S utilization

5.2.1.  Example of different TS Granularities

   In this example, two interfaces with homogeneous hierarchies but
   different Tributary Slot Types are considered.  The first one
   supports a [RFC4328] interface (TS granularity=2) while the second
   one supports G.709-2012 interface with fallback procedure disabled
   (TS granularity=3).  Both of them support ODU1->ODU2->ODU3 hierarchy
   and priorities 0 and 3.  Suppose that in this interface the ODU3
   signal type can be both switched or terminated, the ODU2 can only be
   terminated, and the ODU1 switched only.  For the advertisement of the
   capabilities of such interfaces, two different ISCDs are used and the
   format of their SCSIs is as follows:










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   SCSI of ISCD 1 - TS granularity=2
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU1  |  #stages= 2   |0|1|  0  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU2  | Stage#2=ODU3  |       Padding (all zeros)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU1 at Prio 0      |     Unres ODU1 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 1   |1|0|  1  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  |        Padding (all zeros)                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU2 at Prio 0      |     Unres ODU2 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU3  |  #stages= 0   |1|1|  2  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU3 at Prio 0      |     Unres ODU3 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Figure 9: Example 2.1 - Different TS Granularities utilization - ISCD
                                     1





















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   SCSI of ISCD 2 - TS granularity=3
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU1  |  #stages= 2   |0|1|  0  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU2  | Stage#2=ODU3  |       Padding (all zeros)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU1 at Prio 0      |     Unres ODU1 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 1   |1|0|  1  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  |        Padding (all zeros)                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU2 at Prio 0      |     Unres ODU2 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU3  |  #stages= 0   |1|1|  3  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Unres ODU3 at Prio 0      |     Unres ODU3 at Prio 3      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     Figure 10: Example 2.1 - Different TS Granularities utilization -
                                  ISCD 2

   A particular case in which hierarchies with the same muxing tree but
   with different exported TS granularity MUST be considered as non-
   homogenous hierarchies.  This is the case in which an H-LPS and the
   client LSP are terminated on the same egress node.  What can happen
   is that a loose Explicit Route Object (ERO) is used at the hop where
   the signaled LSP is nested into the Hierarchical-LSP (H-LSP)
   (penultimate hop of the LSP).

   In the following figure, node C receives from A a loose ERO towards
   node E and must choose between the ODU2 H-LSP on if1 or the one on
   if2.  In this case, the H-LSP on if1 exports a TS=1.25Gbps, and if2 a
   TS=2.5Gbps, the service LSP being signaled needs a 1.25Gbps tributary
   slot, only the H-LSP on if1 can be used to reach node E. For further
   details, please see section 4.1 of the [OTN-INFO].






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                          ODU0-LSP
         ..........................................................+
         |                                                         |
         |                                     ODU2-H-LSP          |
         |                         +-------------------------------+
         |                         |                               |
      +--+--+      +-----+      +-----+ if1     +-----+         +-----+
      |     | OTU3 |     | OTU3 |     |---------|     |---------|     |
      |  A  +------+  B  +------+  C  | if2     |  D  |         |  E  |
      |     |      |     |      |     |---------|     |---------|     |
      +-----+      +-----+      +-----+         +-----+         +-----+

            ... Service LSP
            --- H-LSP


    Figure 11: Example - Service LSP and H-LSP terminating on the same
                                   node

5.3.  Example of ODUflex advertisement

   In this example, the advertisement of an ODUflex->ODU3 hierarchy is
   shown.  In case of ODUflex advertisement, the MAX LSP Bandwidth needs
   to be advertised and, in some cases, information about the Unreserved
   bandwidth could also be useful.  The amount of Unreserved bandwidth
   does not give a clear indication of how many ODUflex LSP can be set
   up either at the MAX LSP Bandwidth or at different rates, as it gives
   no information about the spatial allocation of the free TSs.

   An indication of the amount of Unreserved bandwidth could be useful
   during the path computation process, as shown in the following
   example.  Supposing there are two TE-links (A and B) with MAX LSP
   Bandwidth equal to 10 Gbps each.  In the case where 50Gbps of
   Unreserved Bandwidth are available on Link A, 10Gbps on Link B, and 3
   ODUflex LSPs of 10 GBps each have to be restored, for sure only one
   can be restored along Link B and it is probable, but not certain,
   that two of them can be restored along Link A. T, S and TS
   granularity fields are not relevant to this example (filled with Xs).

   In the case of ODUflex advertisement, the Type 2 Bandwidth sub-TLV is
   used.










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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Type = 2 (Unres/MAX-var)   |           Length  = 72        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S. type=ODUflex|  #stages= 1   |X|X|X X X|0 0 0| Priority(8)   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Stage#1=ODU3 |          Padding (all zeros)                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 0              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 1              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 2              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 3              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 4              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 5              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 6              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Unreserved Bandwidth at priority 7              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 0              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 1              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 2              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 3              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 4              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 5              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 6              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 MAX LSP  Bandwidth at priority 7              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


               Figure 12: Example 3 - ODUflex advertisement







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5.4.  Example of single stage muxing

   Supposing there is 1 OTU4 component link supporting single stage
   muxing of ODU1, ODU2, ODU3 and ODUflex, the supported hierarchy can
   be summarized in a tree as in the following figure.  For sake of
   simplicity, we also assume that only priorities 0 and 3 are
   supported.  T, S and TS granularity fields are not relevant to this
   example(filled with Xs).


          ODU1 ODU2  ODU3 ODUflex
             \   \    /   /
              \   \  /   /
               \   \/   /
                  ODU4


   and the related SCSIs as follows:

































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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU4  |  #stages= 0   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU4 at Prio 0 =1     |    Unres ODU4 at Prio 3 =1    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU1  |  #stages= 1   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU4  |            Padding (all zeros)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU1 at Prio 0 =40    |    Unres ODU1 at Prio 3 =40   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 1   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU4  |            Padding (all zeros)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU2 at Prio 0 =10    |    Unres ODU2 at Prio 3 =10   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU3  |  #stages= 1   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU4  |            Padding (all zeros)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU3 at Prio 0 =2     |    Unres ODU3 at Prio 3 =2    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Type = 2 (Unres/MAX-var)   |           Length = 24         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S. type=ODUflex|  #stages= 1   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Stage#1=ODU4 |            Padding (all zeros)                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Unreserved Bandwidth at priority 0 =100Gbps        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Unreserved Bandwidth at priority 3 =100Gbps        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              MAX LSP Bandwidth at priority 0 =100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              MAX LSP Bandwidth at priority 3 =100Gbps         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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                Figure 13: Example 4 - Single stage muxing

5.5.  Example of multi stage muxing - Unbundled link

   Supposing there is 1 OTU4 component link with muxing capabilities as
   shown in the following figure:


          ODU2 ODU0    ODUflex ODU0
             \ /            \ /
              |              |
            ODU3           ODU2
               \            /
                \          /
                 \        /
                  \      /
                    ODU4


   and supported priorities 0 and 3, the advertisement is composed by
   the following Bandwidth sub-TLVs (T and S fields are not relevant to
   this example and filled with Xs):





























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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU4  |  #stages= 0   |X|X|  1  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU4 at Prio 0 =1     |    Unres ODU4 at Prio 3 =1    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU3  |  #stages= 1   |X|X|  1  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Stage#1=ODU4 |         Padding (all zeros)                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU3 at Prio 0 =2     |    Unres ODU3 at Prio 3 =2    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 1   |X|X|  1  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Stage#1=ODU4 |         Padding (all zeros)                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU2 at Prio 0 =10    |    Unres ODU2 at Prio 3 =10   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 2   |X|X|  0  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU2 at Prio 0 =8     |    Unres ODU2 at Prio 3 =8    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU0  |  #stages= 2   |X|X|  0  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU0 at Prio 0 =64    |    Unres ODU0 at Prio 3 =64   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU0  |  #stages= 2   |X|X|  0  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU2  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU0 at Prio 0 =80    |    Unres ODU0 at Prio 3 =80   |



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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Type = 2 (Unres/MAX-var)   |           Length = 24         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S.type=ODUflex |  #stages= 2   |X|X|  0  |0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU2  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Unreserved Bandwidth at priority 0 =100Gbps        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Unreserved Bandwidth at priority 3 =100Gbps        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            MAX LSP Bandwidth at priority 0 =10Gbps            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            MAX LSP Bandwidth at priority 3 =10Gbps            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



        Figure 14: Example 5 - Multi stage muxing - Unbundled link

5.6.  Example of multi stage muxing - Bundled links

   In this example, 2 OTU4 component links with the same supported TS
   granularity and homogeneous muxing hierarchies are considered.  The
   following muxing capabilities trees are supported:


   Component Link#1      Component Link#2
      ODU2 ODU0             ODU2 ODU0
         \ /                   \ /
          |                     |
         ODU3                  ODU3
          |                     |
         ODU4                  ODU4


   Considering only supported priorities 0 and 3, the advertisement is
   as follows (T, S and TS granularity fields are not relevant to this
   example and filled with Xs):












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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU4  |  #stages= 0   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU4 at Prio 0 =2     |    Unres ODU4 at Prio 3 =2    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU3  |  #stages= 1   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Stage#1=ODU4 |          Padding (all zeros)                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU3 at Prio 0 =4     |    Unres ODU3 at Prio 3 =4    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 2   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU2 at Prio 0 =16    |    Unres ODU2 at Prio 3 =16   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU0  |  #stages= 2   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU0 at Prio 0 =128   |    Unres ODU0 at Prio 3 =128  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



         Figure 15: Example 6 - Multi stage muxing - Bundled links

5.7.  Example of component links with non-homogeneous hierarchies

   In this example, 2 OTU4 component links with the same supported TS
   granularity and non-homogeneous muxing hierarchies are considered.
   The following muxing capabilities trees are supported:








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   Component Link#1      Component Link#2
      ODU2 ODU0             ODU1 ODU0
         \ /                   \ /
          |                     |
         ODU3                  ODU2
          |                     |
         ODU4                  ODU4


   Considering only supported priorities 0 and 3, the advertisement uses
   two different ISCDs, one for each hierarchy (T, S and TS granularity
   fields are not relevant to this example and filled with Xs).  In the
   following figure, the SCSI of each ISCD is shown:






































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   SCSI of ISCD 1 - Component Link#1

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU4  |  #stages= 0   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU4 at Prio 0 =1     |    Unres ODU4 at Prio 3 =1    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU3  |  #stages= 1   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Stage#1=ODU4 |           Padding (all zeros)                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU3 at Prio 0 =2     |    Unres ODU3 at Prio 3 =2    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 2   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU2 at Prio 0 =8     |    Unres ODU2 at Prio 3 =8    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU0  |  #stages= 2   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU3  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU0 at Prio 0 =64    |    Unres ODU0 at Prio 3 =64   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


        Figure 16: Example 7 - Multi stage muxing - Non-homogeneous
                           hierarchies - ISCD 1












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   SCSI of ISCD 2 - Component Link#2

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 8          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU4  |  #stages= 0   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU4 at Prio 0 =1     |    Unres ODU4 at Prio 3 =1    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU2  |  #stages= 1   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Stage#1=ODU4 |           Padding (all zeros)                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU2 at Prio 0 =10    |    Unres ODU2 at Prio 3 =10   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU1  |  #stages= 2   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU2  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU1 at Prio 0 =40    |    Unres ODU1 at Prio 3 =40   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Type = 1 (Unres-fix)   |           Length = 12         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Sig type=ODU0  |  #stages= 2   |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Stage#1=ODU2  | Stage#2=ODU4  |    Padding (all zeros)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Unres ODU0 at Prio 0 =80    |    Unres ODU0 at Prio 3 =80   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


        Figure 17: Example 7 - Multi stage muxing - Non-homogeneous
                           hierarchies - ISCD 2


6.  OSPFv2 scalability

   This document does not introduce OSPF scalability issues with respect
   to existing GMPLS encoding and does not require any modification to
   flooding frequency.  Moreover, the design of the encoding has been
   carried out taking into account bandwidth optimization, and in
   particular:



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      - Only unreserved and MAX LSP Bandwidth related to supported
      priorities are advertised

      - With respect of fixed containers, only the number of available
      containers is advertised instead of available bandwidth so to use
      only 16 bits per container instead of 32 (as per former GMPLS
      encoding

   In order to further reduce the amount of data advertised it is
   RECOMMENDED to bundle component links with homogeneous hierarchies as
   described in [RFC4201] and illustrated in Section 5.6.


7.  Compatibility

   All implementations of this document MAY also support advertisement
   as defined in [RFC4328].  When nodes support both advertisement
   methods, implementations MUST support the configuration of which
   advertisement method is followed.  The choice of which is used is
   based on policy and beyond the scope of this document.  This enables
   nodes following each method to identify similar supporting nodes and
   compute paths using only the appropriate nodes.


8.  Security Considerations

   This document extends [RFC4203].  As with[RFC4203], it specifies the
   contents of Opaque LSAs in OSPFv2.  As Opaque LSAs are not used for
   SPF computation or normal routing, the extensions specified here have
   no direct effect on IP routing.  Tampering with GMPLS TE LSAs may
   have an effect on the underlying transport (optical and/or SONET-SDH)
   network.  [RFC3630] notes that the security mechanisms described in
   [RFC2328] apply to Opaque LSAs carried in OSPFv2.  An analysis of the
   security of OSPF is provided in [RFC6863] and applies to the
   extensions to OSPF as described in this document.  Any new mechanisms
   developed to protect the transmission of information carried in
   Opaque LSAs will also automatically protect the extensions defined in
   this document.

   For security threats, defensive techniques, monitoring/detection/
   reporting of security attacks and requirements please refer to
   [RFC5920].


9.  IANA Considerations






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9.1.  Switching types

   Upon approval of this document, IANA will make the assignment in the
   "Switching Types" section of the "GMPLS Signaling Parameters"
   registry located at
   http://www.iana.org/assignments/gmpls-sig-parameters:


   Value      Name                          Reference
   ---------  --------------------------    ----------
   110 (*)     OTN-TDM capable (OTN-TDM)    [This.I-D]

   (*) Suggested value


   Same type of modification needs to applied to the IANA-GMPLS-TC-MIB
   at https://www.iana.org/assignments/ianagmplstc-mib/ianagmplstc-mib,
   where the value:

   OTN-TDM (110), -- Time-Division-Multiplex OTN-TDM capable

   Will be added to the IANAGmplsSwitchingTypeTC ::= TEXTUAL-CONVENTION
   syntax list.

9.2.  New sub-TLVs

   This document defines 2 new sub-TLVs that are carried in Interface
   Switching Capability Descriptors [RFC4203] with Signal Type OTN-TDM.
   Each sub-TLV includes a 16-bit type identifier (the T-field).  The
   same T-field values are applicable to the new sub-TLV.

   Upon approval of this document, IANA will create and maintain a new
   sub-registry, the "Types for sub-TLVs of OTN-TDM SCSI (Switch
   Capability-Specific Information)" registry under the "Open Shortest
   Path First (OSPF) Traffic Engineering TLVs" registry, see http://
   www.iana.org/assignments/ospf-traffic-eng-tlvs/
   ospf-traffic-eng-tlvs.xml, with the sub-TLV types as follows:


      This document defines new sub-TLV types as follows:

   Value      Sub-TLV                       Reference
   ---------  --------------------------    ----------
   0           Reserved                     [This.I-D]
   1           Unreserved Bandwidth for     [This.I-D]
               fixed containers
   2           Unreserved/MAX Bandwidth for [This.I-D]
               flexible containers



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   3-65535     Unassigned

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


10.  Contributors

      Diego Caviglia, Ericsson

      Via E.Melen, 77 - Genova - Italy

      Email: diego.caviglia@ericsson.com



      Dan Li, Huawei Technologies

      Bantian, Longgang District - Shenzhen 518129 P.R.China

      Email: danli@huawei.com



      Pietro Vittorio Grandi, Alcatel-Lucent

      Via Trento, 30 - Vimercate - Italy

      Email: pietro_vittorio.grandi@alcatel-lucent.com



      Khuzema Pithewan, Infinera Corporation

      140 Caspian CT., Sunnyvale - CA - USA

      Email: kpithewan@infinera.com



      Xiaobing Zi, Huawei Technologies

      Email: zixiaobing@huawei.com



      Francesco Fondelli, Ericsson




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      Email: francesco.fondelli@ericsson.com



      Marco Corsi

      EMail: corsi.marco@gmail.com



      Eve Varma, Alcatel-Lucent

      EMail: eve.varma@alcatel-lucent.com



      Jonathan Sadler, Tellabs

      EMail: jonathan.sadler@tellabs.com



      Lyndon Ong, Ciena

      EMail: lyong@ciena.com



      Ashok Kunjidhapatham

      akunjidhapatham@infinera.com



      Snigdho Bardalai

      sbardalai@infinera.com



      Steve Balls

      Steve.Balls@metaswitch.com



      Jonathan Hardwick




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      Jonathan.Hardwick@metaswitch.com



      Xihua Fu

      fu.xihua@zte.com.cn



      Cyril Margaria

      cyril.margaria@nsn.com

      Malcolm Betts

      Malcolm.betts@zte.com.cn




11.  Acknowledgements

   The authors would like to thank Fred Gruman and Lou Berger for the
   precious comments and suggestions.


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.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              September 2003.

   [RFC4201]  Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling
              in MPLS Traffic Engineering (TE)", RFC 4201, October 2005.

   [RFC4203]  Kompella, K. and Y. Rekhter, "OSPF Extensions in Support
              of Generalized Multi-Protocol Label Switching (GMPLS)",
              RFC 4203, October 2005.

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



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12.2.  Informative References

   [OTN-FWK]  F.Zhang, D.Li, H.Li, S.Belotti, D.Ceccarelli, "Framework
              for GMPLS and PCE Control of G.709 Optical Transport
              networks, work in progress
              draft-ietf-ccamp-gmpls-g709-framework-13", June 2013.

   [OTN-INFO]
              S.Belotti, P.Grandi, D.Ceccarelli, D.Caviglia, F.Zhang,
              D.Li, "Information model for G.709 Optical Transport
              Networks (OTN), work in progress
              draft-ietf-ccamp-otn-g709-info-model-09", June 2013.

   [OTN-SIG]  F.Zhang, G.Zhang, S.Belotti, D.Ceccarelli, K.Pithewan,
              "Generalized Multi-Protocol Label Switching (GMPLS)
              Signaling Extensions for the evolving G.709 Optical
              Transport Networks Control, work in progress
              draft-ietf-ccamp-gmpls-signaling-g709v3-11", June 2013.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

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

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

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

   [RFC6566]  Lee, Y., Bernstein, G., Li, D., and G. Martinelli, "A
              Framework for the Control of Wavelength Switched Optical
              Networks (WSONs) with Impairments", RFC 6566, March 2012.

   [RFC6863]  Hartman, S. and D. Zhang, "Analysis of OSPF Security
              According to the Keying and Authentication for Routing
              Protocols (KARP) Design Guide", RFC 6863, March 2013.

   [SWCAP-UPDT]
              F.Zhang, D.Li, H.Li, S.Belotti, D.Ceccarelli, "Framework
              for GMPLS and PCE Control of G.709 Optical Transport
              networks, work in progress
              draft-ietf-ccamp-gmpls-g709-framework-13", June 2013.





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Authors' Addresses

   Daniele Ceccarelli (editor)
   Ericsson
   Via E.Melen 77
   Genova - Erzelli
   Italy

   Email: daniele.ceccarelli@ericsson.com


   Fatai Zhang
   Huawei Technologies
   F3-5-B R&D Center, Huawei Base
   Shenzhen 518129 P.R.China  Bantian, Longgang District
   Phone: +86-755-28972912

   Email: zhangfatai@huawei.com


   Sergio Belotti
   Alcatel-Lucent
   Via Trento, 30
   Vimercate
   Italy

   Email: sergio.belotti@alcatel-lucent.com


   Rajan Rao
   Infinera Corporation
   140, Caspian CT.
   Sunnyvale, CA-94089
   USA

   Email: rrao@infinera.com


   John E Drake
   Juniper


   Email: jdrake@juniper.net








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