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Versions: (draft-ietf-ccamp-transport-nbi-use-cases) 00 01 02

CCAMP Working Group                                             I. Busi
Internet Draft                                                   Huawei
Intended status: Informational                                  D. King
                                                   Lancaster University
                                                               H. Zheng
                                                                 Huawei
                                                                  Y. Xu
                                                                  CAICT

Expires: January 2019                                      July 2, 2018





          Transport Northbound Interface Applicability Statement
              draft-ietf-ccamp-transport-nbi-app-statement-02


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
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   This Internet-Draft will expire on January 2, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors. All rights reserved.



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

Abstract

   Transport network domains, including Optical Transport Network (OTN)
   and Wavelength Division Multiplexing (WDM) networks, are typically
   deployed based on a single vendor or technology platforms. They are
   often managed using proprietary interfaces to dedicated Element
   Management Systems (EMS), Network Management Systems (NMS) and
   increasingly Software Defined Network (SDN) controllers.

   A well-defined open interface to each domain management system or
   controller is required for network operators to facilitate control
   automation and orchestrate end-to-end services across multi-domain
   networks. These functions may be enabled using standardized data
   models (e.g. YANG), and appropriate protocol (e.g., RESTCONF).

   This document analyses the applicability of the YANG models being
   defined by IETF (TEAS and CCAMP WGs in particular) to support OTN
   single and multi-domain scenarios.

Table of Contents

   1. Introduction...................................................4
      1.1. Scope of this document....................................4
      1.2. Assumptions...............................................5
   2. Terminology....................................................6
   3. Conventions used in this document..............................6
      3.1. Topology and traffic flow processing......................6
      3.2. JSON code.................................................7
   4. Scenarios Description..........................................8
      4.1. Reference Network.........................................8
         4.1.1. Single-Domain Scenario..............................11
         4.1.2. Multi-Domain Scenario...............................11
      4.2. Topology Abstractions....................................11
      4.3. Service Configuration....................................13
         4.3.1. ODU Transit.........................................14


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         4.3.2. EPL over ODU........................................15
         4.3.3. Other OTN Clients Services..........................16
         4.3.4. EVPL over ODU.......................................17
         4.3.5. EVPLAN and EVPTree Services.........................18
         4.3.6. Dynamic Service Configuration.......................19
      4.4. Multi-function Access Links..............................20
      4.5. Protection and Restoration Configuration.................21
         4.5.1. Linear Protection (end-to-end)......................21
         4.5.2. Segmented Protection................................23
         4.5.3. End-to-End Dynamic restoration......................23
         4.5.4. Segmented Dynamic Restoration.......................24
      4.6. Service Modification and Deletion........................24
      4.7. Notification.............................................25
      4.8. Path Computation with Constraint.........................25
   5. YANG Model Analysis...........................................26
      5.1. YANG Models for Topology Abstraction.....................26
         5.1.1. Domain 1 Topology Abstraction.......................27
         5.1.2. Domain 2 Grey (Type A) Topology Abstraction.........28
         5.1.3. Domain 3 Grey (Type B) Topology Abstraction.........28
         5.1.4. Multi-domain Topology Stitching.....................28
         5.1.5. Access Links........................................29
      5.2. YANG Models for Service Configuration....................31
         5.2.1. ODU Transit Service.................................33
            5.2.1.1. Single Domain Example..........................35
         5.2.2. EPL over ODU Service................................36
         5.2.3. Other OTN Client Services...........................38
         5.2.4. EVPL over ODU Service...............................38
      5.3. YANG Models for Protection Configuration.................39
         5.3.1. Linear Protection (end-to-end)......................39
         5.3.2. Segmented Protection................................39
   6. Security Considerations.......................................39
   7. IANA Considerations...........................................39
   8. References....................................................39
      8.1. Normative References.....................................39
      8.2. Informative References...................................41
   9. Acknowledgments...............................................41
      Appendix A Validating a JSON fragment against a YANG Model....43
      A.1. Manipulation of JSON fragments...........................43
      A.2. Comments in JSON fragments...............................44
      A.3. Validation of JSON fragments: DSDL-based approach........44
      A.4. Validation of JSON fragments: why not using a XSD-based
      approach......................................................45
      Appendix B Detailed JSON Examples.............................46
      B.1. JSON Examples for Topology Abstractions..................46
         B.1.1. JSON Code: mpi1-otn-topology.json...................46


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      B.2. JSON Examples for Service Configuration..................73
         B.2.1. JSON Code:  mpi1-odu2-service-config.json...........73
         B.2.2. JSON Code: mpi1-odu2-tunnel-config.json.............77
         B.2.3. JSON Code: mpi1-epl-service-config.json.............80

1. Introduction

   Transport of packet services are critical for a wide-range of
   applications and services, including: data center and LAN
   interconnects, Internet service backhauling, mobile backhaul and
   enterprise Carrier Ethernet Services. These services are typically
   setup using stovepipe NMS and EMS platforms, often requiring
   propriety management platforms and legacy management interfaces. A
   clear goal of operators will be to automate setup of transport
   services across multiple transport technology domains.

   A common open interface (API) to each domain controller and or
   management system is pre-requisite for network operators to control
   multi-vendor and multi-domain networks and enable also service
   provisioning coordination/automation. This can be achieved by using
   standardized YANG models, used together with an appropriate protocol
   (e.g., [RESTCONF]).

   This document analyses the applicability of the YANG models being
   defined by IETF (TEAS and CCAMP WGs in particular) to support OTN
   single and multi-domain scenarios.

1.1. Scope of this document

   This document assumes a reference architecture, including
   interfaces, based on the Abstraction and Control of Traffic-
   Engineered Networks (ACTN), defined in [ACTN-Frame].

   The focus of this document is on the MPI (interface between the
   Multi Domain Service Coordinator (MDSC) and a Physical Network
   Controller (PNC), controlling a transport network domain).

   It is worth noting that the same MPI analyzed in this document could
   be used between hierarchical MDSC controllers, as shown in Figure 4
   of [ACTN-Frame].

   Detailed analysis of the CMI (interface between the Customer Network
   Controller (CNC) and the MDSC) as well as of the interface between
   service and network orchestrators are outside the scope of this



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   document. However, some considerations and assumptions about the
   information could be described when needed.

   The relationship between the current IETF YANG models and the type
   of ACTN interfaces can be found in [ACTN-YANG]. Therefore, it
   considers the TE Topology YANG model defined in [TE-TOPO], with the
   OTN Topology augmentation defined in [OTN-TOPO] and the TE Tunnel
   YANG model defined in [TE-TUNNEL], with the OTN Tunnel augmentation
   defined in [OTN-TUNNEL].

   The analysis of how to use the attributes in the I2RS Topology YANG
   model, defined in [I2RS-TOPO], is for further study.

   The ONF Technical Recommendations for Functional Requirements for
   the transport API in [ONF TR-527] and the ONF transport API multi-
   domain examples in [ONF GitHub] have been considered as an input for
   defining the reference scenarios analyzed in this document.

1.2. Assumptions

   This document is making the following assumptions, still to be
   validated with TEAS WG:

   1. The MDSC can request, at the MPI, a PNC to setup a Transit Tunnel
      Segment using the TE Tunnel YANG model: in this case, since the
      endpoints of the E2E Tunnel are outside the domain controlled by
      that PNC, the MDSC would not specify any source or destination
      TTP (i.e., it would leave the source, destination, src-tp-id and
      dst-tp-id attributes empty) for the tunnel and it would use the
      explicit-route-object/route-object-include-exclude list to
      specify the ingress and egress links for each path of the Transit
      Tunnel Segment.

   2. Each PNC provides to the MDSC, at the MPI, the list of available
      timeslots on the inter-domain links using the TE Topology YANG
      model and OTN Topology augmentation. The TE Topology YANG model
      in [TE-TOPO] is being updated to report the label set
      information.

   This document is also making the following assumptions, still to be
   validated with CCAMP WG:

   1. The topology information for the Ethernet access links are
      modelled using the YANG model defined in [Client-Topo].



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   2. The service information for Ethernet and other OTN client layer
      services are modelled using the YANG model defined in [Client-
      Signal].

2. Terminology

   Domain: defined as a collection of network elements within a common
   realm of address space or path computation responsibility [RFC5151]

   E-LINE: Ethernet Line

   EPL: Ethernet Private Line

   EVPL: Ethernet Virtual Private Line

   OTN: Optical Transport Network

   Service: A service in the context of this document can be considered
   as some form of connectivity between customer sites across the
   network operator's network [RFC8309]

   Service Model: As described in [RFC8309] it describes a service and
   the parameters of the service in a portable way that can be used
   uniformly and independent of the equipment and operating
   environment.

   UNI: User Network Interface

   MDSC: Multi-Domain Service Coordinator

   CNC: Customer Network Controller

   PNC: Provisioning Network Controller

   MAC Bridging: Virtual LANs (VLANs) on IEEE 802.3 Ethernet network

3. Conventions used in this document

3.1. Topology and traffic flow processing

   The traffic flow between different nodes is specified as an ordered
   list of nodes, separated with commas, indicating within the brackets
   the processing within each node:

      <node> (<processing>){, <node> (<processing>)}


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   The order represents the order of traffic flow being forwarded
   through the network.

   The processing can be either an adaptation of a client layer into a
   server layer "(client -> server)" or switching at a given layer
   "([switching])". Multi-layer switching is indicated by two layer
   switching with client/server adaptation: "([client] -> [server])".

   For example, the following traffic flow:

      R1 ([PKT] -> ODU2), S3 ([ODU2]), S5 ([ODU2]), S6 ([ODU2]),
      R3 (ODU2 -> [PKT])

   Node R1 is switching at the packet (PKT) layer and mapping packets
   into an ODU2 before transmission to node S3. Nodes S3, S5 and S6 are
   switching at the ODU2 layer: S3 sends the ODU2 traffic to S5 which
   then sends it to S6 which finally sends to R3. Node R3 terminates
   the ODU2 from S6 before switching at the packet (PKT) layer.

   The paths of working and protection transport entities are specified
   as an ordered list of nodes, separated with commas:

      <node> {, <node>}

   The order represents the order of traffic flow being forwarded
   through the network in the forward direction. In case of
   bidirectional paths, the forward and backward directions are
   selected arbitrarily, but the convention is consistent between
   working/protection path pairs as well as across multiple domains.

3.2. JSON code

   This document provides some detailed JSON code examples to describe
   how the YANG models being developed by IETF (TEAS and CCAMP WG in
   particular) can be used.

   The examples are provided using JSON because JSON code is easier for
   humans to read and write.

   Different objects need to have an identifier. The convention used to
   create mnemonic identifiers is to use the object name (e.g., S3 for
   node S3), followed by its type (e.g., NODE), separated by an "-",
   followed by "-ID". For example, the mnemonic identifier for node S3
   would be S3-NODE-ID.



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   JSON language does not support the insertion of comments that have
   been instead found to be useful when writing the examples. This
   document inserts comments into the JSON code as JSON name/value pair
   with the JSON name string starting with the "//" characters. For
   example, when describing the example of a TE Topology instance
   representing the ODU Abstract Topology exposed by the Transport PNC,
   the following comment has been added to the JSON code:

      "// comment": "ODU Abstract Topology @ MPI",

   The JSON code examples provided in this document have been validated
   against the YANG models following the validation process described
   in Appendix A, which would not consider the comments.

   In order to have successful validation of the examples, some
   numbering scheme has been defined to assign identifiers to the
   different entities which would pass the syntax checks. In that case,
   to simplify the reading, another JSON name/value pair, formatted as
   a comment and using the mnemonic identifiers is also provided. For
   example, the identifier of node S3 (S3-NODE-ID) has been assumed to
   be "10.0.0.3" and would be shown in the JSON code example using the
   two JSON name/value pair:

      "// te-node-id": "S3-NODE-ID",

      "te-node-id": "10.0.0.3",

   The first JSON name/value pair will be automatically removed in the
   first step of the validation process while the second JSON
   name/value pair will be validate against the YANG model definitions.

4. Scenarios Description

4.1. Reference Network

   The physical topology of the reference network is shown in Figure 1.
   It represents an OTN network composed of three transport network
   domains providing transport services to an IP customer network
   through eight access links:








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                ........................
   ..........   :                      :
            :   :   Network domain 1   :   .............
   Customer:   :                      :   :           :
    domain :   :     S1 -------+      :   :  Network  :
           :   :    /           \     :   :  domain 3 :   ..........
       R1 ------- S3 ----- S4    \    :   :           :   :
           :   :    \        \    S2 --------+        :   :Customer
           :   :     \        \    |  :   :   \       :   : domain
           :   :      S5       \   |  :   :    \      :   :
       R2 ------+    /  \       \  |  :   :    S31 --------- R7
           :   : \  /    \       \ |  :   :   /   \   :   :
           :   :  S6 ---- S7 ---- S8 ------ S32   S33 ------ R8
           :   : /        |       |   :   : / \   /   :   :.......
       R3 ------+         |       |   :   :/   S34    :          :
           :   :..........|.......|...:   /    /      :          :
   ........:              |       |      /:.../.......:          :
                          |       |     /    /                   :
               ...........|.......|..../..../...                 :
               :          |       |   /    /   :    ..............
               : Network  |       |  /    /    :    :
               : domain 2 |       | /    /     :    :Customer
               :         S11 ---- S12   /      :    : domain
               :        /          | \ /       :    :
               :     S13     S14   | S15 ------------- R4
               :     |  \   /   \  |    \      :    :
               :     |   S16     \ |     \     :    :
               :     |  /         S17 -- S18 --------- R5
               :     | /             \   /     :    :
               :    S19 ---- S20 ---- S21 ------------ R6
               :                               :    :
               :...............................:    :.............

                         Figure 1 Reference network

   This document assumes that all the transport network switching nodes
   Si are OTN switching nodes capable to switch only in the electrical
   domain (ODU switching only) and that all the Si-Sj OTN links within
   the transport network (intra-domain or inter-domain) are 100G links
   while the access Ri-Sj links are 10G links. Different technologies
   can be used at the access links (e.g., Ethernet, STM-n, OTN).

   It is also assumed that, within the transport network, the
   physical/optical interconnections supporting the Si-Sj OTN links (up
   to the OTU4 trail), are pre-configured using mechanisms which are


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   outside the scope of this document and are not exposed at the MPIs
   to the MDSC.

   The transport domain control architecture, shown in Figure 2,
   follows the ACTN architecture and framework document [ACTN-Frame],
   and functional components:

                           --------------
                          |              |
                          |     CNC      |
                          |              |
                           --------------
                                 |
             ....................|....................... CMI
                                 |
                          ----------------
                         |                |
                         |      MDSC      |
                         |                |
                          ----------------
                            /   |    \
                           /    |     \
            ............../.....|......\................ MPIs
                         /      |       \
                        /   ----------   \
                       /   |   PNC2   |   \
                      /     ----------     \
             ----------         |           \
            |   PNC1   |      -----          \
             ----------     (       )      ----------
                 |         (         )    |   PNC3   |
               -----      (  Network  )    ----------
             (       )    (  Domain 2 )        |
            (         )    (         )       -----
           (  Network  )    (       )      (       )
           (  Domain 1 )      -----       (         )
            (         )                  (  Network  )
             (       )                   (  Domain 3 )
               -----                      (         )
                                           (       )
                                             -----

                      Figure 2 Controlling Hierarchy




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   The ACTN framework facilitates the detachment of the network and
   service control from the underlying technology and help the customer
   express the network as desired by business needs. Therefore, care
   must be taken to keep minimal dependency on the CMI (or no
   dependency at all) with respect to the network domain technologies.
   The MPI instead requires some specialization according to the domain
   technology.

   This document assumes that the CNC controls the customer IP network
   and requests, at the CMI, transport connectivity between IP routers.
   The MDSC coordinates, via three MPIs, the control of a multi-domain
   transport network through three PNCs.

   The control interfaces within scope of this document are the three
   MPIs, while the control interface(s) between the CNC and the IP
   routers is outside the scope of this document. It is also assumed
   that the CMI allows the CNC to provide all the information that is
   required by the MDSC to properly configure the transport
   connectivity requested by the customer.

4.1.1. Single-Domain Scenario

   In case the CNC requests transport connectivity between IP routers
   attached to the same transport domain (e.g., between R1 and R3 in
   Figure 1), the MDSC can just pass the service request to the PNC
   controlling that domain (e.g., PNC1 in Figure 2) and let the PNC
   take decisions about how to implement the service (e.g., setting up
   the intra-domain end-to-end OTN connection).

4.1.2. Multi-Domain Scenario

   In case the CNC requests transport connectivity between IP routers
   attached to different transport domains (e.g., between R1 and R5),
   the MDSC needs to coordinate the setup of a multi-domain end-to-end
   OTN connection across multiple PNCs (e.g., PNC1, PNC2 and PNC3 in in
   Figure 2) as well as to coordinate the configuration of the service
   with the PNCs controlling the edge domains (e.g., PNC1 and PNC2 in
   Figure 2).

4.2. Topology Abstractions

   Abstraction provides a selective method for representing
   connectivity information within a domain. There are multiple methods
   to abstract a network topology. This document assumes the
   abstraction method defined in [RFC7926]:


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     "Abstraction is the process of applying policy to the available TE
     information within a domain, to produce selective information that
     represents the potential ability to connect across the domain.
     Thus, abstraction does not necessarily offer all possible
     connectivity options, but presents a general view of potential
     connectivity according to the policies that determine how the
     domain's administrator wants to allow the domain resources to be
     used."

   [ACTN-Frame] Provides the context of topology abstraction in the
   ACTN architecture and discusses a few alternatives for the
   abstraction methods for both packet and optical networks. This is an
   important consideration since the choice of the abstraction method
   impacts protocol design and the information it carries.  According
   to [ACTN-Frame], there are three types of topology:

   o  White topology: This is a case where the PNC provides the actual
      network topology to the MDSC without any hiding or filtering. In
      this case, the MDSC has the full knowledge of the underlying
      network topology;

   o  Black topology: The entire domain network is abstracted as a
      single virtual node with the access/egress links without
      disclosing any node internal connectivity information;

   o  Grey topology: This abstraction level is between black topology
      and white topology from a granularity point of view. This is
      abstraction of TE tunnels for all pairs of border nodes. We may
      further differentiate from a perspective of how to abstract
      internal TE resources between the pairs of border nodes:

       - Grey topology type A: border nodes with a TE links between
          them in a full mesh fashion;

       - Grey topology type B: border nodes with some internal
          abstracted nodes and abstracted links.

   Each PNC should provide the MDSC a topology abstraction of the
   domain's network topology.

   Each PNC provides topology abstraction of its own domain topology
   independently from each other and therefore it is possible that
   different PNCs provide different types of topology abstractions.




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   The MPI operates on the abstract topology regardless on the type of
   abstraction provided by the PNC.

   To analyze how the MPI operates on abstract topologies independently
   from the topology abstraction provided by each PNC and, therefore,
   that that different PNCs can provide different topology
   abstractions, it is assumed that:

   o  PNC1 provides a topology abstraction which exposes at MPI1 an
      abstract node and an abstract link for each physical node and
      link within network domain 1

   o  PNC2 provides a topology abstraction which exposes at MPI2 a
      single abstract node (representing the whole network domain) with
      abstract links representing only the inter-domain physical links

   o  PNC3 provides a topology abstraction which exposes at MPI3 two
      abstract nodes (called AN31 and AN32). They abstract respectively
      nodes S31+S33 and nodes S32+S34. At MPI3, only the abstract nodes
      should be reported: the mapping between the abstract nodes (AN31
      and AN32) and the physical nodes (S31, S32, S33 and S34) should
      be done internally by PNC3.

   The MDSC should be capable to stitch together each abstracted
   topology to build its own view of the multi-domain network topology.
   The process may require suitable oversight, including administrative
   configuration and trust models, but this is out of scope for this
   document.

   The MDSC can also provide topology abstraction of its own view of
   the multi-domain network topology at its CMIs depending on the
   customers' needs: it can provide different types of topology
   abstractions at different CMIs.

4.3. Service Configuration

   In the following scenarios, it is assumed that the CNC is capable to
   request service connectivity from the MDSC to support IP routers
   connectivity.

   The type of services could depend of the type of physical links
   (e.g. OTN link, ETH link or SDH link) between the routers and
   transport network.




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   The control of different adaptations   inside IP routers, Ri (PKT ->
   foo) and Rj (foo -> PKT), are assumed to be performed by means that
   are not under the control of, and not visible to, the MDSC nor to
   the PNCs. Therefore, these mechanisms are outside the scope of this
   document.

   It is just assumed that the CNC is capable to request the proper
   configuration of the different adaptation functions inside the
   customer's IP routers, by means which are outside the scope of this
   document.

4.3.1. ODU Transit

   The physical links interconnecting the IP routers and the transport
   network can be OTN links. In this case, it is assumed that the
   physical/optical interconnections below the ODU layer (up to the
   OTU2 trail) are pre-configured using mechanisms which are outside
   the scope of this document and not exposed at the MPIs to the MDSC.

   To setup a 10Gb IP link between R1 and R5, an ODU2 end-to-end data
   plane connection needs be created between R1 and R5, crossing
   transport nodes S3, S1, S2, S31, S33, S34, S15 and S18 which belong
   to different PNC domains.

   The traffic flow between R1 and R5 can be summarized as:

      R1 ([PKT] -> ODU2), S3 ([ODU2]), S1 ([ODU2]), S2 ([ODU2]),
      S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
      S15 ([ODU2]), S18 ([ODU2]), R5 (ODU2 -> [PKT])

   It is assumed that the CNC requests, via the CMI, the setup of an
   ODU2 transit service, providing all the information that the MDSC
   needs to understand that it shall setup a multi-domain ODU2 segment
   connection between nodes S3 and S18.

   In case the CNC needs the setup of a 10Gb IP link between R1 and R3
   (single-domain service request), the traffic flow between R1 and R3
   can be summarized as:

      R1 ([PKT] -> ODU2), S3 ([ODU2]), S5 ([ODU2]), S6 ([ODU2]),
      R3 (ODU2 -> [PKT])

   Since the CNC is unaware of the transport network domains, it
   requests the setup of an ODU2 transit service in the same way as



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   before, regardless the fact the fact that this is a single-domain
   service.

   It is assumed that the information provided at the CMI is sufficient
   for the MDSC to understand that this is a single-domain service
   request.

   The MDSC can then just request PNC1 to setup a single-domain ODU2
   data plane segment connection between nodes S3 and S6.

4.3.2. EPL over ODU

   The physical links interconnecting the IP routers and the transport
   network can be Ethernet links. In this case, it is assumed that the
   Ethernet physical interconnections below the MAC layer (up to the
   OTU2 trail) are pre-configured using mechanisms which are outside
   the scope of this document and not exposed at the MPIs to the MDSC.

   To setup a 10Gb IP link between R1 and R5, an EPL service needs to
   be created between R1 and R5, supported by an ODU2 end-to-end data
   plane connection between transport nodes S3 and S18, crossing
   transport nodes S1, S2, S31, S33, S34 and S15 which belong to
   different PNC domains.

   The traffic flow between R1 and R5 can be summarized as:

      R1 ([PKT] -> ETH), S3 (ETH -> [ODU2]), S1 ([ODU2]),
      S2 ([ODU2]), S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
      S15 ([ODU2]), S18 ([ODU2] -> ETH), R5 (ETH -> [PKT])

   It is assumed that the CNC requests, via the CMI, the setup of an
   EPL service, providing all the information that the MDSC needs to
   understand that it shall coordinate the three PNCs to setup a multi-
   domain ODU2 end-to-end connection between nodes S3 and S18 as well
   as the configuration of the adaptation functions inside nodes S3 and
   S18: S3 (ETH -> [ODU2]), S18 ([ODU2] -> ETH), S18 (ETH -> [ODU2])
   and S3 ([ODU2] -> ETH).

   In case the CNC needs the setup of a 10Gb IP link between R1 and R3
   (single-domain service request), the traffic flow between R1 and R3
   can be summarized as:

      R1 ([PKT] -> ETH), S3 (ETH -> [ODU2]), S5 ([ODU2]),
      S6 ([ODU2] -> ETH), R3 (ETH-> [PKT])



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   As described in section 4.3.1, the CNC requests the setup of an EPL
   service in the same way as before and the information provided at
   the CMI is sufficient for the MDSC to understand that this is a
   single-domain service request.

   The MDSC can then just request PNC1 to setup a single-domain EPL
   service between nodes S3 and S6. PNC1 can take care of setting up
   the single-domain ODU2 end-to-end connection between nodes S3 and S6
   as well as of configuring the adaptation functions on these edge
   nodes.

4.3.3. Other OTN Clients Services

   [ITU-T G.709] defines mappings of different client layers into
   ODU. Most of them are used to provide Private Line services over
   an OTN transport network supporting a variety of types of physical
   access links (e.g., Ethernet, SDH STM-N, Fibre Channel, InfiniBand,
   etc.).

   The physical links interconnecting the IP routers and the transport
   network can be any of these types.

   In order to setup a 10Gb IP link between R1 and R5 using, for
   example SDH physical links between the IP routers and the transport
   network, an STM-64 Private Line service needs to be created between
   R1 and R5, supported by ODU2 end-to-end data plane connection
   between transport nodes S3 and S18, crossing transport nodes S1, S2,
   S31, S33, S34 and S15 which belong to different PNC domains.

   The traffic flow between R1 and R5 can be summarized as:

      R1 ([PKT] -> STM-64), S3 (STM-64 -> [ODU2]), S1 ([ODU2]),
      S2 ([ODU2]), S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
      S15 ([ODU2]), S18 ([ODU2] -> STM-64), R5 (STM-64 -> [PKT])

   As described in section 4.3.2, it is assumed that the CNC is
   capable, via the CMI, to request the setup of an STM-64 Private Line
   service, providing all the information that the MDSC needs to
   coordinate the setup of a multi-domain ODU2 connection as well as
   the adaptation functions on the edge nodes.

   In the single-domain case (10Gb IP link between R1 and R3), the
   traffic flow between R1 and R3 can be summarized as:




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      R1 ([PKT] -> STM-64), S3 (STM-64 -> [ODU2]), S5 ([ODU2]),
      S6 ([ODU2] -> STM-64), R3 (STM-64 -> [PKT])

   As described in section 4.3.1, the CNC requests the setup of an STM-
   64 Private Line service in the same way as before and the
   information provided at the CMI is sufficient for the MDSC to
   understand that this is a single-domain service request.

   As described in section 4.3.2, the MDSC could just request PNC1 to
   setup a single-domain STM-64 Private Line service between nodes S3
   and S6.

4.3.4. EVPL over ODU

   When the physical links interconnecting the IP routers and the
   transport network are Ethernet links, it is also possible that
   different Ethernet services (e.g., EVPL) can share the same physical
   link using different VLANs.

   To setup two 1Gb IP links between R1 to R3 and between R1 and R5,
   two EVPL services need to be created, supported by two ODU0 end-to-
   end connections respectively between S3 and S6, crossing transport
   node S5, and between S3 and S18, crossing transport nodes S1, S2,
   S31, S33, S34 and S15 which belong to different PNC domains.

   Since the two EVPL services are sharing the same Ethernet physical
   link between R1 and S3, different VLAN IDs are associated with
   different EVPL services: for example, VLAN IDs 10 and 20
   respectively.

   The traffic flow between R1 and R5 can be summarized as:

      R1 ([PKT] -> VLAN), S3 (VLAN -> [ODU0]), S1 ([ODU0]),
      S2 ([ODU0]), S31 ([ODU0]), S33 ([ODU0]), S34 ([ODU0]),
      S15 ([ODU0]), S18 ([ODU0] -> VLAN), R5 (VLAN -> [PKT])

   The traffic flow between R1 and R3 can be summarized as:

      R1 ([PKT] -> VLAN), S3 (VLAN -> [ODU0]), S5 ([ODU0]),
      S6 ([ODU0] -> VLAN), R3 (VLAN -> [PKT])

   As described in section 4.3.2, it is assumed that the CNC is
   capable, via the CMI, to request the setup of these EVPL services,
   providing all the information that the MDSC needs to understand that
   it need to request PNC1 to setup an EVPL service between nodes S3


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   and S6 (single-domain service request) and it also needs to
   coordinate the setup of a multi-domain ODU0 connection between nodes
   S3 and S16 as well as the adaptation functions on these edge nodes.

4.3.5. EVPLAN and EVPTree Services

   When the physical links interconnecting the IP routers and the
   transport network are Ethernet links, multipoint Ethernet services
   (e.g, EPLAN and EPTree) can also be supported. It is also possible
   that multiple Ethernet services (e.g, EVPL, EVPLAN and EVPTree)
   share the same physical link using different VLANs.

   Note - it is assumed that EPLAN and EPTree services can be supported
   by configuring EVPLAN and EVPTree with port mapping.

   Since this EVPLAN/EVPTree service can share the same Ethernet
   physical links between IP routers and transport nodes (e.g., with
   the EVPL services described in section 4.3.4), a different VLAN ID
   (e.g., 30) can be associated with this EVPLAN/EVPTree service.

   In order to setup an IP subnet between R1, R2, R3 and R5, an
   EVPLAN/EVPTree service needs to be created, supported by two ODUflex
   end-to-end connections respectively between S3 and S6, crossing
   transport node S5, and between S3 and S18, crossing transport nodes
   S1, S2, S31, S33, S34 and S15 which belong to different PNC domains.

   Some MAC Bridging capabilities are also required on some nodes at
   the edge of the transport network: for example Ethernet Bridging
   capabilities can be configured in nodes S3 and S6:

   o  MAC Bridging in node S3 is needed to select, based on the MAC
      Destination Address, whether received Ethernet frames should be
      forwarded to R1 or to the ODUflex terminating on node S6 or to
      the other ODUflex terminating on node S18;

   o  MAC bridging function in node S6 is needed to select, based on
      the MAC Destination Address, whether received Ethernet frames
      should be sent to R2 or to R3 or to the ODUflex terminating on
      node S3.

   In order to support an EVPTree service instead of an EVPLAN,
   additional configuration of the Ethernet Bridging capabilities on
   the nodes at the edge of the transport network is required.




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   The traffic flows between R1 and R3, between R3 and R5 and between
   R1 and R5 can be summarized as:

      R1 ([PKT] -> VLAN), S3 (VLAN -> [MAC] -> [ODUflex]),
      S5 ([ODUflex]), S6 ([ODUflex] -> [MAC] -> VLAN),
      R3 (VLAN -> [PKT])

      R3 ([PKT] -> VLAN), S6 (VLAN -> [MAC] -> [ODUflex]),
      S5 ([ODUflex]), S3 ([ODUflex] -> [MAC] -> [ODUflex]),
      S1 ([ODUflex]), S2 ([ODUflex]), S31 ([ODUflex]),
      S33 ([ODUflex]), S34 ([ODUflex]),
      S15 ([ODUflex]), S18 ([ODUflex] -> VLAN), R5 (VLAN -> [PKT])

      R1 ([PKT] -> VLAN), S3 (VLAN -> [MAC] -> [ODUflex]),
      S1 ([ODUflex]), S2 ([ODUflex]), S31 ([ODUflex]),
      S33 ([ODUflex]), S34 ([ODUflex]),
      S15 ([ODUflex]), S18 ([ODUflex] -> VLAN), R5 (VLAN -> [PKT])

   As described in section 4.3.2, it is assumed that the CNC is
   capable, via the CMI, to request the setup of this EVPLAN/EVPTree
   service, providing all the information that the MDSC needs to
   understand that it need to request PNC1 to setup an ODUflex
   connection between nodes S3 and S6 (single-domain service request)
   and it also needs to coordinate the setup of a multi-domain ODUflex
   connection between nodes S3 and S16 as well as the MAC bridging and
   the adaptation functions on these edge nodes.

   In case the CNC needs the setup of an EVPLAN/EVPTree service only
   between R1, R2 and R3 (single-domain service request), it would
   request the setup of this service in the same way as before and the
   information provided at the CMI is sufficient for the MDSC to
   understand that this is a single-domain service request.

   The MDSC can then just request PNC1 to setup a single-domain
   EVPLAN/EVPTree service between nodes S3 and S6. PNC1 can take care
   of setting up the single-domain ODUflex end-to-end connection
   between nodes S3 and S6 as well as of configuring the MAC bridging
   and the adaptation functions on these edge nodes.

4.3.6. Dynamic Service Configuration

   Given the service established in the previous sections, there is a
   demand for an update of some service characteristics. A
   straightforward approach would be terminate the current service and
   replace with a new one. Another more advanced approach would be


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   dynamic configuration, in which case there will be no interruption
   for the connection.

   An example application would be updating the SLA information for a
   certain connection. For example, an ODU transit connection is set up
   according to section 4.3.1, with the corresponding SLA level of 'no
   protection'. After the establishment of this connection, the user
   would like to enhance this service by providing a restoration after
   potential failure, and a request is generated on the CMI. In this
   case, after receiving the request, the MDSC would need to send an
   update message to the PNC, changing the SLA parameters in TE Tunnel
   model. Then the connection characteristic would be changed by PNC,
   and a notification would be sent to MDSC for acknowledgement.

4.4. Multi-function Access Links

   Some physical links interconnecting the IP routers and the transport
   network can be configured in different modes, e.g., as OTU2 or STM-
   64 or 10GE.

   This configuration can be done a-priori by means outside the scope
   of this document. In this case, these links will appear at the MPI
   either as an ODU Link or as a STM-64 Link or as a 10GE Link
   (depending on the a-priori configuration) and will be controlled at
   the MPI as discussed in section 4.3.

   It is also possible not to configure these links a-priori and give
   the control to the MPI to decide, based on the service
   configuration, how to configure it.

   For example, if the physical link between R1 and S3 is a multi-
   functional access link while the physical links between R7 and S31
   and between R5 and S18 are STM-64 and 10GE physical links
   respectively, it is possible to configure either an STM-64 Private
   Line service between R1 and R7 or an EPL service between R1 and R5.

   The traffic flow between R1 and R7 can be summarized as:

      R1 ([PKT] -> STM-64), S3 (STM-64 -> [ODU2]), S1 ([ODU2]),
      S2 ([ODU2]), S31 ([ODU2] -> STM-64), R3 (STM-64 -> [PKT])

   The traffic flow between R1 and R5 can be summarized as:





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      R1 ([PKT] -> ETH), S3 (ETH -> [ODU2]), S1 ([ODU2]),
      S2 ([ODU2]), S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
      S15 ([ODU2]), S18 ([ODU2] -> ETH), R5 (ETH -> [PKT])

   As described in section 4.3.2, it is assumed that the CNC is
   capable, via the CMI, to request the setup either an STM-64 Private
   Line service between R1 and R7 or an EPL service between R1 and R5,
   providing all the information that the MDSC needs to understand that
   it need to coordinate the setup of a multi-domain ODU2 connection,
   either between nodes S3 and S31, or between nodes S3 and S18, as
   well as the adaptation functions on these edge nodes, and in
   particular whether the multi-function access link on between R1 and
   S3 should operate as an STM-64 or as a 10GE link.

4.5. Protection and Restoration Configuration

   Protection switching provides a pre-allocated survivability
   mechanism, typically provided via linear protection methods and
   would be configured to operate as 1+1 unidirectional (the most
   common OTN protection method), 1+1 bidirectional or 1:n
   bidirectional. This ensures fast and simple service survivability.

   Restoration methods would provide capability to reroute and restore
   connectivity traffic around network faults, without the network
   penalty imposed with dedicated 1+1 protection schemes.

   This section describes only services which are protected with linear
   protection and with dynamic restoration.

   The MDSC needs to be capable to coordinate different PNCs to
   configure protection switching when requesting the setup of the
   protected connectivity services described in section 4.3.

   Since in these service examples, switching within the transport
   network domain is performed only in the OTN ODU layer, also
   protection switching within the transport network domain can only be
   provided at the OTN ODU layer.

4.5.1. Linear Protection (end-to-end)

   In order to protect any service defined in section 4.3 from failures
   within the OTN multi-domain transport network, the MDSC should be
   capable to coordinate different PNCs to configure and control OTN
   linear protection in the data plane between nodes S3 and node S18.



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   It is assumed that the OTN linear protection is configured to with
   1+1 unidirectional protection switching type, as defined in [ITU-T
   G.808.1] and [ITU-T G.873.1], as well as in [RFC4427].

   In these scenarios, a working transport entity and a protection
   transport entity, as defined in [ITU-T G.808.1], (or a working LSP
   and a protection LSP, as defined in [RFC4427]) should be configured
   in the data plane.

   Two cases can be considered:

   o  In one case, the working and protection transport entities pass
      through the same PNC domains:

         Working transport entity:     S3, S1, S2,
                                       S31, S33, S34,
                                       S15, S18

         Protection transport entity:  S3, S4, S8,
                                       S32,
                                       S12, S17, S18

   o  In another case, the working and protection transport entities
      can pass through different PNC domains:

         Working transport entity:     S3, S5, S7,
                                       S11, S12, S17, S18

         Protection transport entity:  S3, S1, S2,
                                       S31, S33, S34,
                                       S15, S18

   The PNCs should be capable to report to the MDSC which is the active
   transport entity, as defined in [ITU-T G.808.1], in the data plane.

   Given the fast dynamic of protection switching operations in the
   data plane (50ms recovery time), this reporting is not expected to
   be in real-time.

   It is also worth noting that with unidirectional protection
   switching, e.g., 1+1 unidirectional protection switching, the active
   transport entity may be different in the two directions.





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4.5.2. Segmented Protection

   To protect any service defined in section 4.3 from failures within
   the OTN multi-domain transport network, the MDSC should be capable
   to request each PNC to configure OTN intra-domain protection when
   requesting the setup of the ODU2 data plane connection segment.

   If PNC1 provides linear protection, the working and protection
   transport entities could be:

      Working transport entity:     S3, S1, S2

      Protection transport entity:  S3, S4, S8, S2

   If PNC2 provides linear protection, the working and protection
   transport entities could be:

      Working transport entity:     S15, S18

      Protection transport entity:  S15, S12, S17, S18

   If PNC3 provides linear protection, the working and protection
   transport entities could be:

      Working transport entity:     S31, S33, S34

      Protection transport entity:  S31, S32, S34

4.5.3. End-to-End Dynamic restoration

   To restore any service defined in section 4.3 from failures within
   the OTN multi-domain transport network, the MDSC should be capable
   to coordinate different PNCs to configure and control OTN end-to-end
   dynamic Restoration in the data plane between nodes S3 and node S18.
   For example, the MDSC can request the PNC1, PNC2 and PNC3 to create
   a service with no-protection, MDSC set the end-to-end service with
   the dynamic restoration.

         Working transport entity:     S3, S1, S2,
                                       S31, S33, S34,
                                       S15, S18

   When a link failure between S1 and s2 occurred in network domain 1,
   PNC1 does not restore the tunnel and send the alarm notification to
   the MDSC, MDSC will perform the end-to-end restoration.


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         Restored transport entity:    S3, S4, S8,
                                       S12, S15, S18

4.5.4. Segmented Dynamic Restoration

   To restore any service defined in section 4.3 from failures within
   the OTN multi-domain transport network, the MDSC should be capable
   to coordinate different PNCs to configure and control OTN segmented
   dynamic Restoration in the data plane between nodes S3 and node S18.

         Working transport entity:     S3, S1, S2,
                                       S31, S33, S34,
                                       S15, S18

   When a link failure between S1 and s2 occurred in network domain 1,
   PNC1 will restore the tunnel and send the alarm or tunnel update
   notification to the MDSC, MDSC will update the restored tunnel.

         Restored transport entity:    S3, S4, S8, S2
                                       S31, S33, S34,
                                       S15, S18

   When a link failure between network domain 1 and network domain 2
   occurred, PNC1 and PNC2 will send the alarm notification to the
   MDSC, MDSC will update the restored tunnel.

         Restored transport entity:    S3, S4, S8,
                                       S12, S15, S18

   In order to improve the efficiency of recovery, the controller can
   establish a recovery path in a concurrent way. When the recovery
   fails in one domain or one network element, the rollback operation
   should be supported.

   The creation of the recovery path by the controller can use the
   method of "make-before-break", in order to reduce the impact of the
   recovery operation on the services.

4.6. Service Modification and Deletion

   To be discussed in future versions of this document.






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4.7. Notification

   To realize the topology update, service update and restoration
   function, following notification type should be supported.

   1. Object create

   2. Object delete

   3. Object state change

   4. Alarm

   Because there are three types of topology abstraction type defined
   in section 4.2, the notification should also be abstracted. The PNC
   and MDSC should coordinate together to determine the notification
   policy, such as when an intra-domain alarm occurred, the PNC may not
   report the alarm but the service state change notification to the
   MDSC.

4.8. Path Computation with Constraint

   It is possible to have constraint during path computation procedure,
   typical cases include IRO/XRO and so on. This information is carried
   in the TE Tunnel model and used when there is a request with
   constraint. Consider the example in section 4.3.1. , the request can
   be a Tunnel from R1 to R5 with an IRO from S2 to S31, then a
   qualified feedback would become:

   R1 ([PKT] -> ODU2), S3 ([ODU2]), S1 ([ODU2]), S2 ([ODU2]),
   S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
   S15 ([ODU2]), S18 ([ODU2]), R5 (ODU2 -> [PKT])

   If the request covers the IRO from S8 to S12, then the above path
   would not be qualified, while a possible computation result may be:

   R1 ([PKT] -> ODU2), S3 ([ODU2]), S1 ([ODU2]), S2 ([ODU2]),
   S8 ([ODU2]), S12 ([ODU2]), S15 ([ODU2]), S18 ([ODU2]), R5 (ODU2 ->
   [PKT])

   Similarly, the XRO can be represented by TE tunnel model as well.

   When there is a technology specific network (e.g, OTN), the
   corresponding technology (OTN) model should also be used to specify



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   the tunnel information on MPI, with the constraint included in TE
   Tunnel model.

5. YANG Model Analysis

   This section provides a high-level overview of how IETF YANG models
   can be used at the MPIs, between the MDSC and the PNCs, to support
   the scenarios described in section 4.

   Section 5.1 describes the different topology abstractions provided
   to the MDSC by each PNC via its own MPI.

   Section 5.2 describes how the MDSC can coordinate different requests
   to different PNCs, via their own MPIs, to setup the different
   services described in section 4.3.

   Section 5.3 describes how the protection scenarios can be deployed,
   including end-to-end protection and segment protection, for both
   intra-domain and inter-domain scenario.

5.1. YANG Models for Topology Abstraction

   Each PNC reports its respective abstract topology to the MDSC, as
   described in section 4.2.























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5.1.1. Domain 1 Topology Abstraction

   PNC1 provides the required topology abstraction to expose at its MPI
   toward the MDSC (called "MPI1") one TE Topology instance for the ODU
   layer (called "MPI1 ODU Topology"), containing one TE Node (called
   "ODU Node") for each physical node, as shown in Figure 3 below.

                  ..................................
                  :                                :
                  :   ODU Abstract Topology @ MPI  :
                  :        Gotham City Area        :
                  :     Metro Transport Network    :
                  :                                :
                  :        +----+        +----+    :
                  :        |    |S1-1    |    |S2-1:
                  :        | S1 |--------| S2 |- - - - -(R4)
                  :        +----+    S2-2+----+    :
                  :     S1-2/               |S2-3  :
                  :    S3-2/ Robinson Park  |      :
                  :    +----+   +----+      |      :
                  :    |    |3 1|    |      |      :
          (R1)- - - - -| S3 |---| S4 |      |      :
                  :S3-1+----+   +----+      |      :
                  :   S3-4 \        \S4-2   |      :
                  :         \S5-1    \      |      :
                  :        +----+     \     |      :
                  :        |    |      \S8-3|      :
                  :        | S5 |       \   |      :
                  :        +----+ Metro  \  |S8-2  :
          (R2)- - - - -   2/ E  \3 Main   \ |      :
                  :S6-1 \ /3 a E \1 Ring   \|      :
                  :    +----+s-n+----+   +----+    :
                  :    |    |t d|    |   |    |S8-1:
                  :    | S6 |---| S7 |---| S8 |- - - - -(R5)
                  :    +----+4 2+----+3 4+----+    :
                  :     /                          :
          (R3)- - - - -                            :
                  :S6-2                            :
                  :................................:

      Figure 3 Abstract Topology exposed at MPI1 (MPI1 ODU Topology)

   The ODU Nodes in Figure 3 are using the same names as the physical
   nodes to simplify the description of the mapping between the ODU
   Nodes exposed by the Transport PNCs at the MPI and the physical


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   nodes in the data plane. This does not correspond to the reality of
   the usage of the topology model, as described in section 4.3 of [TE-
   TOPO], in which renaming by the client it is necessary.

   As described in section 4.1, it is assumed that the physical links
   between the physical nodes are pre-configured and therefore PNC1
   exports at MPI1 one TE Link (called "ODU Link") for each of these
   OTU4 trails.

   Appendix B.1.1 provides the detailed JSON code ("mpi1-otn-
   topology.json") describing how this ODU Topology is reported by the
   PNC, using the [TE-TOPO] and [OTN-TOPO] YANG models at MPI1.

5.1.2. Domain 2 Grey (Type A) Topology Abstraction

   PNC2 provides the required topology abstraction to expose at its MPI
   towards the MDSC (called "MPI2") only one abstract node (i.e., AN2),
   with only inter-domain and access links, is reported at the MPI2.

5.1.3. Domain 3 Grey (Type B) Topology Abstraction

   PNC3 provides the required topology abstraction to expose at its MPI
   towards the MDSC (called "MPI3") only two abstract nodes (i.e., AN31
   and AN32), with internal links, inter-domain links and access links.

5.1.4. Multi-domain Topology Stitching

   As assumed in the beginning of this section, MDSC does not have any
   knowledge of the topologies of each domain until each PNC reports
   its own abstraction topology, so the MDSC needs to merge together
   the abstract topologies provided by different PNCs, at the MPIs, to
   build its own topology view, as described in section 4.3 of [TE-
   TOPO].

   Given the topologies reported from multiple PNCs, the MDSC need to
   stitch the multi-domain topology and obtain the full map of
   topology. The topology of each domain main be in an abstracted shape
   (refer to section 5.2 of [ACTN-Fwk] for different level of
   abstraction), while the inter-domain link information MUST be
   complete and fully configured by the MDSC.

   The inter-domain link information is reported to the MDSC by the two
   PNCs, controlling the two ends of the inter-domain link.




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   The MDSC needs to understand how to "stitch" together these inter-
   domain links.

   One possibility is to use the plug-id information, defined in [TE-
   TOPO]: two inter-domain links reporting the same plug-id value can
   be merged as a single intra-domain link within any MDSC native
   topology. The value of the reported plug-id information can be
   either assigned by a central network authority, and configured
   within the two PNC domains, or it can be discovered using automatic
   discovery mechanisms (e.g., LMP-based, as defined in [RFC6898]).

   In case the plug-id values are assigned by a central authority, it
   is under the central authority responsibility to assign unique
   values.

   In case the plug-id values are automatically discovered, the
   information discovered by the automatic discovery mechanisms needs
   to be encoded as a bit string within the plug-id value. This
   encoding is implementation specific but the encoding rules need to
   be consistent across all the PNCs.

   In case of co-existence within the same network of multiple sources
   for the plug-id (e.g., central authority and automatic discovery or
   even different automatic discovery mechanisms), it is RECOMMENDED
   that the plug-id namespace is partitioned to avoid that different
   sources assign the same plug-id value to different inter-domain
   link. The encoding of the plug-id namespace within the plug-id value
   is implementation specific but needs to be consistent across all the
   PNCs.

   Another possibility is to pre-configure, either in the adjacent PNCs
   or in the MDSC, the association between the inter-domain link
   identifiers (topology-id, node-id and tp-id) assigned by the two
   adjacent PNCs to the same inter-domain link.

   This last scenario requires further investigation and will be
   discussed in a future version of this document.

5.1.5. Access Links

   Access links in Figure 3 are shown as ODU Links: the modeling of the
   access links for other access technologies is currently an open
   issue.




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   The modeling of the access link in case of non-ODU access technology
   has also an impact on the need to model ODU TTPs and layer
   transition capabilities on the edge nodes (e.g., nodes S2, S3, S6
   and S8 in Figure 3).

   If, for example, the physical NE S6 is implemented in a "pizza box",
   the data plane would have only set of ODU termination resources
   (where up to 2xODU4, 4xODU3, 20xODU2, 80xODU1, 160xODU0 and
   160xODUflex can be terminated). The traffic coming from each of the
   10GE access links can be mapped into any of these ODU terminations.

   Instead if, for example, the physical NE S6 can be implemented as a
   multi-board system where access links reside on different/dedicated
   access cards with separated set of ODU termination resources (where
   up to 1xODU4, 2xODU3, 10xODU2, 40xODU1, 80xODU0 and 80xODUflex for
   each resource can be terminated). The traffic coming from one 10GE
   access links can be mapped only into the ODU terminations which
   reside on the same access card.

   The more generic implementation option for a physical NE (e.g., S6)
   would be case is of a multi-board system with multiple access cards
   with separated sets of access links and ODU termination resources
   (where up to 1xODU4, 2xODU3, 10xODU2, 40xODU1, 80xODU0 and
   80xODUflex for each resource can be terminated). The traffic coming
   from each of the 10GE access links on one access card can be mapped
   only into any of the ODU terminations which reside on the same
   access card.

   In the last two cases, only the ODUs terminated on the same access
   card where the access links resides can carry the traffic coming
   from that 10GE access link. Terminated ODUs can instead be sent to
   any of the OTU4 interfaces

   In all these cases, terminated ODUs can be sent to any of the OTU4
   interfaces assuming the implementation is based on a non-blocking
   ODU cross-connect.

   If the access links are reported via MPI in some, still to be
   defined, client topology, it is possible to report each set of ODU
   termination resources as an ODU TTP within the ODU Topology of
   Figure 3 and to use either the inter-layer lock-id or the
   transitional link, as described in sections 3.4 and 3.10 of [TE-
   TOPO], to correlate the access links, in the client topology, with
   the ODU TTPs, in the ODU topology, to which access link are
   connected to.


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5.2. YANG Models for Service Configuration

   The service configuration procedure is assumed to be initiated (step
   1 in Figure 4) at the CMI from CNC to MDSC. Analysis of the CMI
   models is (e.g., L1SM, L2SM, Transport-Service, VN, et al.) is
   outside the scope of this document.

   As described in section 4.3, it is assumed that the CMI YANG models
   provides all the information that allows the MDSC to understand that
   it needs to coordinate the setup of a multi-domain ODU connection
   (or connection segment) and, when needed, also the configuration of
   the adaptation functions in the edge nodes belonging to different
   domains.


































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                                 |
                                 | {1}
                                 V
                          ----------------
                         |           {2}  |
                         | {3}  MDSC      |
                         |                |
                          ----------------
                           ^     ^      ^
                    {3.1}  |     |      |
                 +---------+     |{3.2} |
                 |               |      +----------+
                 |               V                 |
                 |           ----------            |{3.3}
                 |          |   PNC2   |           |
                 |           ----------            |
                 |               ^                 |
                 V               | {4.2}           |
             ----------          V                 |
            |   PNC1   |       -----               V
             ----------      (Network)        ----------
                 ^          ( Domain 2)      |   PNC3   |
                 | {4.1}   (          _)      ----------
                 V          (        )            ^
               -----       C==========D           | {4.3}
             (Network)    /  (       ) \          V
            ( Domain 1)  /     -----    \       -----
           (           )/                \    (Network)
           A===========B                  \  ( Domain 3)
          / (         )                    \(           )
      AP-1   (       )                      X===========Z
               -----                         (         ) \
                                              (       )   AP-2
                                                -----

                    Figure 4 Multi-domain Service Setup

   As an example, the objective in this section is to configure a
   transport service between R1 and R5. The cross-domain routing is
   assumed to be R1 <-> S3 <-> S2 <-> S31 <-> S33 <-> S34 <->S15 <->
   S18 <-> R5.

   According to the different client signal type, there is different
   adaptation required.



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   After receiving such request, MDSC determines the domain sequence,
   i.e., domain 1 <-> domain 2 <-> domain 3, with corresponding PNCs
   and inter-domain links (step 2 in Figure 4).

   As described in [PATH-COMPUTE], the domain sequence can be
   determined by running the MDSC own path computation on the MDSC
   internal topology, defined in section 5.1.4, if and only if the MDSC
   has enough topology information. Otherwise the MDSC can send path
   computation requests to the different PNCs (steps 2.1, 2.2 and 2.3
   in Figure 4) and use this information to determine the optimal path
   on its internal topology and therefore the domain sequence.

   The MDSC will then decompose the tunnel request into a few tunnel
   segments via tunnel model (including both TE tunnel model and OTN
   tunnel model), and request different PNCs to setup each intra-domain
   tunnel segment (steps 3, 3.1, 3.2 and 3.3 in Figure 4).

   Assume that each intra-domain tunnel segment can be set up
   successfully, and each PNC response to the MDSC respectively. Based
   on each segment, MDSC will take care of the configuration of both
   the intra-domain tunnel segment and inter-domain tunnel via
   corresponding MPI (via TE tunnel model and OTN tunnel model). More
   specifically, for the inter-domain configuration, the ts-bitmap and
   tpn attributes need to be configured using the OTN Tunnel model
   [xxx]. Then the end-to-end OTN tunnel will be ready.

   In any case, the access link configuration is done only on the PNCs
   that control the access links (e.g., PNC-1 and PNC-3 in our example)
   and not on the PNCs of transit domain (e.g., PNC-2 in our example).
   Access link will be configured by MDSC after the OTN tunnel is set
   up. Access configuration is different and dependent on the different
   type of service. More details can be found in the following
   sections.

5.2.1. ODU Transit Service

   In this scenario, described in section 4.3.1, the access links are
   configured as ODU Links.

   Since it is assumed that the physical access links are pre-
   configured, each PNC exposes, at its MPI, one TE Link (called "ODU
   Link") for each of these physical access link. These links are
   reported, together with any other ODU internal or inter-domain link,
   within the OTN abstract topology exposed by each PNC, at its own
   MPI.


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   To setup this IP link, between R1 and R5, the CNC requests, at the
   CMI, the MDSC to setup an ODU transit service.

   From the topology information described in section 5.1 above, the
   MDSC understands that R1 is attached to the access link terminating
   on S3-1 LTP in the ODU Topology exposed by PNC1 and that R5 is
   attached to the access link terminating on AN2-1 LTP in the ODU
   Topology exposed by PNC2.

   MDSC would then request, at MPI1, the PNC1 to setup an ODU2 (Transit
   Segment) Tunnel with one primary path between S3-1 and S2-1 LTPs:

   o  Source and Destination TTPs are not specified (since it is a
      Transit Tunnel)

   o  Ingress and egress points are indicated in the route-object-
      include-exclude list of the explicit-route-objects of the primary
      path:

       o The first element references the access link terminating on
          S3-1 LTP

       o The last two element references respectively the inter-domain
          link terminating on S2-1 LTP and the data plane resources
          (i.e., the timeslots and the TPN, called "OTN Label") used by
          the ODU2 connection over that link.

   The configuration of the timeslots used by the ODU2 connection on
   the internal links within a PNC domain (i.e., on the internal links
   domain) is outside the scope of this document since it is a matter
   of the PNC domain internal implementation.

   However, the configuration of the timeslots used by the ODU2
   connection at the transport network domain boundaries (e.g., on the
   inter-domain links) needs to take into account the timeslots
   available on physical nodes belonging to different PNC domains
   (e.g., on node S2 within PNC1 domain and on node S31 within PNC3
   domain).

   The MDSC, when coordinating the setup of a multi-domain ODU
   connection, also configures the data plane resources (i.e., the
   timeslots and the TPN) to be used on the inter-domain links. The
   MDSC can know the timeslots which are available on the physical OTN
   nodes terminating the inter-domain links (e.g., S2 and S31) from the
   OTN Topology information exposed, at the MPIs, by the PNCs


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   controlling the OTN physical nodes (e.g., PNC1 and PNC3 controlling
   respectively the physical nodes S2 and S31).

   Appendix B.2.1 provides the detailed JSON code ("mpi1-odu2-service-
   config.json") describing how the setup of this ODU2 (Transit
   Segment) Tunnel can be requested by the MDSC, using the [TE-TUNNEL]
   and [OTN-TUNNEL] YANG models at MPI1.

   The Transport PNC performs path computation and sets up the ODU2
   cross-connections within the physical nodes S3, S5 and S6, as shown
   in section 4.3.1.

5.2.1.1. Single Domain Example

   To setup an ODU2 end-to-end connection, supporting an IP link,
   between R1 and R3, the CNC requests, at the CMI, the MDSC to setup
   an ODU transit service.

   The Transport PNC reports the status of the created ODU2 (Transit
   Segment) Tunnel and its path within the ODU Topology as shown in
   Figure 5 below:


























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                   ..................................
                   :                                :
                   :   ODU Abstract Topology @ MPI  :
                   :                                :
                   :        +----+        +----+    :
                   :        |    |        |    |    :
                   :        | S1 |--------| S2 |- - - - -(R4)
                   :        +----+        +----+    :
                   :         /               |      :
                   :        /                |      :
                   :    +----+   +----+      |      :
                   :    |    |   |    |      |      :
           (R1)- - - - -  S3 |---| S4 |      |      :
                   :S3-1 <<= +   +----+      |      :
                   :       =        \        |      :
                   :       = \       \       |      :
                   :       == ---+    \      |      :
                   :        =    |     \     |      :
                   :        = S5 |      \    |      :
                   :        == --+       \   |      :
           (R2)- - - - -     =  \         \  |      :
                   :S6-1 \ / =   \         \ |      :
                   :    +--- =   +----+   +----+    :
                   :    |    =   |    |   |    |    :
                   :    | S6 = --| S7 |---| S8 |- - - - -(R5)
                   :    +--- =   +----+   +----+    :
                   :     /   =                      :
           (R3)- - - - -  <<==                      :
                   :S6-2                            :
                   :................................:

                        Figure 5 ODU2 Transit Tunnel

5.2.2. EPL over ODU Service

   In this scenario, described in section 4.3.2, the access links are
   configured as Ethernet Links.

   To setup this IP link, between R1 and R5, the CNC requests, at the
   CMI, the MDSC to setup an EPL service.

   As described in section 5.1.5 above, it is not clear in this case
   how the Ethernet access links between the transport network and the
   IP router, are reported by the PNC to the MDSC.



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   If the 10GE physical links are not reported as ODU links within the
   ODU topology information, described in section 5.1.1 above, than the
   MDSC will not have sufficient information to know that R1 and R5 are
   attached to the access links terminating on S3 and S6.

   Assuming that the MDSC knows how R1 and R3 are attached to the
   transport network, the MDSC would request the Transport PNC to setup
   an ODU2 end-to-end Tunnel between S3 and S6.

   This ODU Tunnel is setup between two TTPs of nodes S3 and S6. In
   case nodes S3 and S6 support more than one TTP, the MDSC should
   decide which TTP to use.

   As discussed in 5.1.5, depending on the different hardware
   implementations of the physical nodes S3 and S6, not all the access
   links can be connected to all the TTPs. The MDSC should therefore
   not only select the optimal TTP but also a TTP that would allow the
   Tunnel to be used by the service.

   It is assumed that in case node S3 or node S6 supports only one TTP,
   this TTP can be accessed by all the access links.

   Appendix B.2.2 provides the detailed JSON code ("mpi1-odu2-tunnel-
   config.json") describing how the setup of this ODU2 (Head Segment)
   Tunnel can be requested by the MDSC, using the [TE-TUNNEL] and [OTN-
   TUNNEL] YANG models at MPI1.

   Once the ODU2 Tunnel setup has been requested, unless there is a
   one-to-one relationship between the S3 and S6 TTPs and the Ethernet
   access links toward R1 and R3 (as in the case, described in section
   5.1.5, where the Ethernet access links reside on different/dedicated
   access card such that the ODU2 tunnel can only carry the Ethernet
   traffic from the only Ethernet access link on the same access card
   where the ODU2 tunnel is terminated), the MDSC also needs to request
   the setup of an EPL service from the access links on S3 and S6,
   attached to R1 and R3, and this ODU2 Tunnel.

   Appendix B.2.3 provides the detailed JSON code ("mpi1-epl-service-
   config.json") describing how the setup of this EPL service using the
   ODU2 Tunnel can be requested by the MDSC, using the [CLIENT-SVC]
   YANG model at MPI1.






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5.2.3. Other OTN Client Services

   In this scenario, the access links are configured as one of the OTN
   clients (e.g., STM-64) links.

   As described in section 4.3.3, the CNC needs to setup an STM-64
   Private Link service, supporting an IP link, between R1 and R3 and
   requests this service at the CMI to the MDSC.

   MDSC needs to setup an STM-64 Private Link service between R1 and R3
   supported by an ODU2 end-to-end connection between S3 and S6.

   As described in section 5.1.5 above, it is not clear in this case
   how the access links (e.g., the STM-N access links) between the
   transport network and the IP router, are reported by the PNC to the
   MDSC.

   The same issues, as described in section 5.2.2, apply here:

   o  the MDSC needs to understand that R1 and R3 are connected,
      thought STM-64 access links, with S3 and S6

   o  the MDSC needs to understand which TTPs in S3 and S6 can be
      accessed by these access links

   o  the MDSC needs to configure the private line service from these
      access links through the ODU2 tunnel

5.2.4. EVPL over ODU Service

   In this scenario, the access links are configured as Ethernet links,
   as described in section 5.2.2 above.

   As described in section 4.3.4, the CNC needs to setup EVPL services,
   supporting IP links, between R1 and R3, as well as between R1 and R4
   and requests these services at the CMI to the MDSC.

   MDSC needs to setup two EVPL services, between R1 and R3, as well as
   between R1 and R4, supported by ODU0 end-to-end connections between
   S3 and S6 and between S3 and S2 respectively.

   As described in section 5.1.5 above, it is not clear in this case
   how the Ethernet access links between the transport network and the
   IP router, are reported by the PNC to the MDSC.



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   The same issues, as described in section 5.1.5 above, apply here:

   o  the MDSC needs to understand that R1, R3 and R4 are connected,
      thought the Ethernet access links, with S3, S6 and S2

   o  the MDSC needs to understand which TTPs in S3, S6 and S2 can be
      accessed by these access links

   o  the MDSC needs to configure the EVPL services from these access
      links through the ODU0 tunnels

   In addition, the MDSC needs to get the information that the access
   links on S3, S6 and S2 are capable to support EVPL (rather than just
   EPL) as well as to coordinate the VLAN configuration, for each EVPL
   service, on these access links (this is a similar issue as the
   timeslot configuration on access links discussed in section 4.3.1
   above).

5.3. YANG Models for Protection Configuration

5.3.1. Linear Protection (end-to-end)

   To be discussed in future versions of this document.

5.3.2. Segmented Protection

   To be discussed in future versions of this document.

6. Security Considerations

   This section is for further study

7. IANA Considerations

   This document requires no IANA actions.

8. References

8.1. Normative References

   [RFC7926] Farrel, A. et al., "Problem Statement and Architecture for
             Information Exchange between Interconnected Traffic-
             Engineered Networks", BCP 206, RFC 7926, July 2016.




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   [RFC4427] Mannie, E., Papadimitriou, D., "Recovery (Protection and
             Restoration) Terminology for Generalized Multi-Protocol
             Label Switching (GMPLS)", RFC 4427, March 2006.

   [ACTN-Frame] Ceccarelli, D., Lee, Y. et al., "Framework for
             Abstraction and Control of Transport Networks", draft-
             ietf-teas-actn-framework, work in progress.

   [ITU-T G.709] ITU-T Recommendation G.709 (06/16), "Interfaces for
             the optical transport network", June 2016.

   [ITU-T G.808.1] ITU-T Recommendation G.808.1 (05/14), "Generic
             protection switching - Linear trail and subnetwork
             protection", May 2014.

   [ITU-T G.873.1] ITU-T Recommendation G.873.1 (05/14), "Optical
             transport network (OTN): Linear protection", May 2014.

   [TE-TOPO] Liu, X. et al., "YANG Data Model for TE Topologies",
             draft-ietf-teas-yang-te-topo, work in progress.

   [OTN-TOPO] Zheng, H. et al., "A YANG Data Model for Optical
             Transport Network Topology", draft-ietf-ccamp-otn-topo-
             yang, work in progress.

   [CLIENT-TOPO]  Zheng, H. et al., "A YANG Data Model for Client-layer
             Topology", draft-zheng-ccamp-client-topo-yang, work in
             progress.

   [TE-TUNNEL] Saad, T. et al., "A YANG Data Model for Traffic
             Engineering Tunnels and Interfaces", draft-ietf-teas-yang-
             te, work in progress.

   [PATH-COMPUTE] Busi, I., Belotti, S. et al, "Yang model for
             requesting Path Computation", draft-busibel-teas-yang-
             path-computation, work in progress.

   [OTN-TUNNEL]   Zheng, H. et al., "OTN Tunnel YANG Model", draft-
             ietf-ccamp-otn-tunnel-model, work in progress.

   [CLIENT-SVC]   Zheng, H. et al., "A YANG Data Model for Optical
             Transport Network Client Signals", draft-zheng-ccamp-otn-
             client-signal-yang, work in progress.




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8.2. Informative References

   [RFC5151] Farrel, A. et al., "Inter-Domain MPLS and GMPLS Traffic
             Engineering --Resource Reservation Protocol-Traffic
             Engineering (RSVP-TE) Extensions", RFC 5151, February
             2008.

   [RFC6898] Li, D. et al., "Link Management Protocol Behavior
             Negotiation and Configuration Modifications", RFC 6898,
             March 2013.

   [RFC8309] Wu, Q. et al., "Service Models Explained", RFC 8309,
             January 2018.

   [ACTN-YANG] Zhang, X. et al., "Applicability of YANG models for
             Abstraction and Control of Traffic Engineered Networks",
             draft-zhang-teas-actn-yang, work in progress.

   [I2RS-TOPO] Clemm, A. et al., "A Data Model for Network Topologies",
             draft-ietf-i2rs-yang-network-topo, work in progress.

   [ONF TR-527] ONF Technical Recommendation TR-527, "Functional
             Requirements for Transport API", June 2016.

   [ONF GitHub] ONF Open Transport (SNOWMASS)
             https://github.com/OpenNetworkingFoundation/Snowmass-
             ONFOpenTransport

9. Acknowledgments

   The authors would like to thank all members of the Transport NBI
   Design Team involved in the definition of use cases, gap analysis
   and guidelines for using the IETF YANG models at the Northbound
   Interface (NBI) of a Transport SDN Controller.

   The authors would like to thank Xian Zhang, Anurag Sharma, Sergio
   Belotti, Tara Cummings, Michael Scharf, Karthik Sethuraman, Oscar
   Gonzalez de Dios, Hans Bjursrom and Italo Busi for having initiated
   the work on gap analysis for transport NBI and having provided
   foundations work for the development of this document.

   The authors would like to thank the authors of the TE Topology and
   Tunnel YANG models [TE-TOPO] and [TE-TUNNEL], in particular Igor
   Bryskin, Vishnu Pavan Beeram, Tarek Saad and Xufeng Liu, for their
   support in addressing any gap identified during the analysis work.


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   This document was prepared using 2-Word-v2.0.template.dot.














































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Appendix A   Validating a JSON fragment against a YANG Model

   The objective is to have a tool that allows validating whether a
   piece of JSON code embedded in an Internet-Draft is compliant with a
   YANG model without using a client/server.

A.1. Manipulation of JSON fragments

   This section describes the various ways JSON fragments are used in
   the I-D processing and how to manage them.

   Let's call "folded-JSON" the JSON embedded in the I-D: it fits the
   72 chars width and it is acceptable for it to be invalid JSON.

   We then define "unfolded-JSON" a valid JSON fragment having the same
   contents of the "folded-JSON " without folding, i.e. limits on the
   text width. The folding/unfolding operation may be done according to
   draft-kwatsen-netmod-artwork-folding. The "unfolded-JSON" can be
   edited by the authors using JSON editors with the advantages of
   syntax validation and pretty-printing.

   Both the "folded" and the "unfolded" JSON fragments can include
   comments having descriptive fields and directives we'll describe
   later to facilitate the reader and enable some automatic processing.

   The presence of comments in the "unfolded-JSON" fragment makes it an
   invalid JSON encoding of YANG data. Therefore we call "naked JSON"
   the JSON where the comments have been stripped out: not only it is
   valid JSON but it is a valid JSON encoding of YANG data.

   The following schema resumes these definitions:

                       unfold_it -->             stripper -->

             Folded-JSON           Unfolded-JSON             Naked JSON

                       <-- fold_it              <-- author edits

   <=72-chars?    MUST              MAY                      MAY

   valid JSON?     MAY             MUST                     MUST

   JSON-encoding   MAY              MAY                     MUST

   of YANG data


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   Our validation toolchain has been designed to take a JSON in any of
   the three formats and validate it automatically against a set of
   relevant YANG modules using available open-source tools. It can be
   found at: https://github.com/GianmarcoBruno/json-yang/

A.2. Comments in JSON fragments

   We found useful to introduce two kinds of comments, both defined as
   key-value pairs where the key starts with "//":

   - free-form descriptive comments, e.g."// COMMENT" : "refine this"
   to describe properties of JSON fragments.

   - machine-usable directives e.g. "// __REFERENCES__DRAFTS__" : {
   "ietf-routing-types@2017-12-04": "rfc8294",} which can be used to
   automatically download from the network the relevant I-Ds or RFCs
   and extract from them the YANG models of interest. This is
   particularly useful to keep consistency when the drafting work is
   rapidly evolving.

A.3. Validation of JSON fragments: DSDL-based approach

   The idea is to generate a JSON driver file (JTOX) from YANG, then
   use it to translate JSON to XML and validate it against the DSDL
   schemas, as shown in Figure 6.

   Useful link: https://github.com/mbj4668/pyang/wiki/XmlJson

                           (2)
               YANG-module ---> DSDL-schemas (RNG,SCH,DSRL)
                      |                  |
                      | (1)              |
                      |                  |
      Config/state  JTOX-file            | (4)
             \        |                  |
              \       |                  |
               \      V                  V
      JSON-file------------> XML-file ----------------> Output
                 (3)

           Figure 6 - DSDL-based approach for JSON code validation




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   In order to allow the use of comments following the convention
   defined in section 3without impacting the validation process, these
   comments will be automatically removed from the JSON-file that will
   be validate.

A.4. Validation of JSON fragments: why not using a XSD-based approach

   This approach has been analyzed and discarded because no longer
   supported by pyang.

   The idea is to convert YANG to XSD, JSON to XML and validate it
   against the XSD, as shown in Figure 7:

                     (1)
         YANG-module ---> XSD-schema - \       (3)
                                        +--> Validation
         JSON-file------> XML-file ----/
                     (2)

           Figure 7 - XSD-based approach for JSON code validation

   The pyang support for the XSD output format was deprecated in 1.5
   and removed in 1.7.1. However pyang 1.7.1 is necessary to work with
   YANG 1.1 so the process shown in Figure 7 will stop just at step
   (1).






















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Appendix B  Detailed JSON Examples

B.1. JSON Examples for Topology Abstractions

B.1.1. JSON Code: mpi1-otn-topology.json

   {
     "// __TITLE__": "ODU Abstract Topology @ MPI1",
     "// __LAST_UPDATE__": "July 2, 2018",
     "// __RESTCONF_OPERATION__": {
       "operation": "GET",
       "url":
         "http://{{PNC1-ADDR}}/restconf/data/ietf-network:networks"
     },
     "// __REFERENCE_DRAFTS__": {
       "ietf-network@2017-12-18":
         "draft-ietf-i2rs-yang-network-topo-20",
       "ietf-network-topology@2017-12-18":
         "draft-ietf-i2rs-yang-network-topo-20",
       "ietf-te-topology@2018-02-21":
         "draft-ietf-teas-yang-te-topo-15",
       "ietf-te-types@2018-02-19": "draft-ietf-teas-yang-te-12",
       "ietf-routing-types@2017-12-04": "rfc8294",
       "ietf-otn-topology@2017-10-30":
         "draft-ietf-ccamp-otn-topo-yang-02",
       "ietf-otn-types@2017-10-30":
         "draft-ietf-ccamp-otn-tunnel-model-01"
     },
     "// __MISSING_ATTRIBUTES__": true,
     "ietf-network:networks": {
       "network": [
         {
           "network-id": "tnbi",
           "network-types": {
             "ietf-te-topology:te-topology": {
               "ietf-otn-topology:otn-topology": {}
             }
           },
           "// __DISCUSS__ ietf-te-topology:provider-id": null,
           "ietf-te-topology:provider-id": 0,
           "// __DISCUSS__ ietf-te-topology:client-id": 0,
           "ietf-te-topology:client-id": 0,
           "// __DISCUSS__ ietf-te-topology:te-topology-id": null,
           "ietf-te-topology:te-topology-id": "tnbi",
           "// comment": [


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             "te container presence requires:           ",
             " provider-id, client-id and te-topology-id"
           ],
           "ietf-te-topology:te": {
             "name": "gotham-city:metro-transport-network"
           },
           "ietf-network:node": [
             {
               "// __NODE__:__DESCRIPTION__": [
                 "S3",
                 "10.0.0.3",
                 "ADM"
               ],
               "node-id": "10.0.0.3",
               "ietf-te-topology:te-node-id": "10.0.0.3",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-node-attributes": {
                   "// comment-on-name": [
                     "Often transport domains contain subdomain      ",
                     "topological partitioning that may be reported  ",
                     "in node te name                                "
                   ],
                   "name": "S3-metro_main_ring-gateway",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },
                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S3-1 LTP",
                     "connected to (C-R1)",
                     "unnumberd/ifIndex: 1",
                     "OTU-2",
                     "tributary port"
                   ],
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "// _OBSOLETE_ ietf-otn-topology:client-facing": [
                       null
                     ],
                     "admin-status": "up",


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                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU2",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S3-2 LTP",
                     "connected to S1-2",
                     "unnumberd/ifIndex: 2",
                     "OTU-4",
                     "line port"
                   ],
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S3-3 LTP",
                     "connected to S4-1",
                     "unnumberd/ifIndex: 3",
                     "OTU-4",
                     "line port"
                   ],
                   "tp-id": "3",
                   "ietf-te-topology:te-tp-id": 3,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",


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                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S3-4 LTP",
                     "connected to S5-1",
                     "unnumberd/ifIndex: 4",
                     "OTU-4",
                     "line port"
                   ],
                   "tp-id": "4",
                   "ietf-te-topology:te-tp-id": 4,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 }
               ]
             },
             {
               "// __NODE__:__DESCRIPTION__": [
                 "S4",
                 "10.0.0.4",
                 "pizza-box"
               ],
               "node-id": "10.0.0.4",
               "ietf-te-topology:te-node-id": "10.0.0.4",
               "ietf-te-topology:te": {
                 "// comment": "TO BE COMPLETED",
                 "oper-status": "up",
                 "te-node-attributes": {
                   "name": "S4-line-metro_main_ring",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },


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                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S4-1 LTP",
                     "connected to S3-3",
                     "unnumberd/ifIndex: 1",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S4-1 LTP",
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S4-2 LTP",
                     "connected to S8-3",
                     "unnumberd/ifIndex: 2",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S4-2 LTP",
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"


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                   }
                 }
               ]
             },
             {
               "// __NODE__:__DESCRIPTION__": [
                 "S1",
                 "10.0.0.1",
                 "pizza-box"
               ],
               "node-id": "10.0.0.1",
               "ietf-te-topology:te-node-id": "10.0.0.1",
               "ietf-te-topology:te": {
                 "// comment": "TO BE COMPLETED",
                 "oper-status": "up",
                 "te-node-attributes": {
                   "name": "S1-robinson_park_ring-line",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },
                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S1-1 LTP",
                     "connected to S2-2",
                     "unnumberd/ifIndex: 1",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S1-1 LTP",
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },


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                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S1-2 LTP",
                     "connected to S3-2",
                     "unnumberd/ifIndex: 2",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S1-2 LTP",
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 }
               ]
             },
             {
               "// __NODE__:__DESCRIPTION__": [
                 "S2",
                 "10.0.0.2",
                 "ADM"
               ],
               "node-id": "10.0.0.2",
               "ietf-te-topology:te-node-id": "10.0.0.2",
               "ietf-te-topology:te": {
                 "// comment": "TO BE COMPLETED",
                 "oper-status": "up",
                 "te-node-attributes": {
                   "name": "S2-robinson_park_ring-access",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },
                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [


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                     "S2-1 LTP",
                     "connected to (C-R4)",
                     "unnumberd/ifIndex: 1",
                     "OTU-2",
                     "tributary port"
                   ],
                   "// comment": "S2-1 LTP",
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "// _OBSOLETE_ ietf-otn-topology:client-facing": [
                       null
                     ],
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU2",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S2-2 LTP",
                     "connected to S1-1",
                     "unnumberd/ifIndex: 2",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S2-2 LTP",
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },


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                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S2-3 LTP",
                     "connected to S8-2",
                     "unnumberd/ifIndex: 3",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S2-3 LTP",
                   "tp-id": "3",
                   "ietf-te-topology:te-tp-id": 3,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 }
               ]
             },
             {
               "// __NODE__:__DESCRIPTION__": [
                 "S7",
                 "10.0.0.7",
                 "ADM"
               ],
               "node-id": "10.0.0.7",
               "ietf-te-topology:te-node-id": "10.0.0.7",
               "ietf-te-topology:te": {
                 "// comment": "TO BE COMPLETED",
                 "oper-status": "up",
                 "te-node-attributes": {
                   "name": "S7-east_end_ring-gateway",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },
                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [


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                     "S7-1 LTP",
                     "connected to S5-3",
                     "unnumberd/ifIndex: 1",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S7-1 LTP",
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S7-2 LTP",
                     "connected to S6-4",
                     "unnumberd/ifIndex: 2",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S7-2 LTP",
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S7-3 LTP",


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                     "connected to S8-4",
                     "unnumberd/ifIndex: 3",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S7-3 LTP",
                   "tp-id": "3",
                   "ietf-te-topology:te-tp-id": 3,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 }
               ]
             },
             {
               "// __NODE__:__DESCRIPTION__": [
                 "S8",
                 "10.0.0.8",
                 "ADM"
               ],
               "node-id": "10.0.0.8",
               "ietf-te-topology:te-node-id": "10.0.0.8",
               "ietf-te-topology:te": {
                 "// comment": "TO BE COMPLETED",
                 "oper-status": "up",
                 "te-node-attributes": {
                   "name": "S8-metro_main_ring-access",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },
                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S8-1 LTP",
                     "connected to (C-R5)",
                     "unnumberd/ifIndex: 1",


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                     "OTU-2",
                     "tributary port"
                   ],
                   "// comment": "S8-1 LTP",
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "// _OBSOLETE_ ietf-otn-topology:client-facing": [
                       null
                     ],
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU2",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S8-2 LTP",
                     "connected to S2-3",
                     "unnumberd/ifIndex: 2",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S8-2 LTP",
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S8-3 LTP",


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                     "connected to S4-2",
                     "unnumberd/ifIndex: 3",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S8-3 LTP",
                   "tp-id": "3",
                   "ietf-te-topology:te-tp-id": 3,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S8-4 LTP",
                     "connected to S7-3",
                     "unnumberd/ifIndex: 4",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S8-4 LTP",
                   "tp-id": "4",
                   "ietf-te-topology:te-tp-id": 4,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 }
               ]
             },
             {
               "// __NODE__:__DESCRIPTION__": [


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                 "S5",
                 "10.0.0.5",
                 "ADM"
               ],
               "node-id": "10.0.0.5",
               "ietf-te-topology:te-node-id": "10.0.0.5",
               "ietf-te-topology:te": {
                 "// comment": "TO BE COMPLETED",
                 "oper-status": "up",
                 "te-node-attributes": {
                   "name": "S5-east_end_ring-gateway",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },
                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S5-1 LTP",
                     "connected to S3-4",
                     "unnumberd/ifIndex: 1",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S5-1 LTP",
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S5-2 LTP",
                     "connected to S6-3",
                     "unnumberd/ifIndex: 2",
                     "OTU-4",


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                     "line port"
                   ],
                   "// comment": "S5-2 LTP",
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S5-3 LTP",
                     "connected to S7-1",
                     "unnumberd/ifIndex: 3",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S5-3 LTP",
                   "tp-id": "3",
                   "ietf-te-topology:te-tp-id": 3,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 }
               ]
             },
             {
               "// __NODE__:__DESCRIPTION__": [
                 "S6",
                 "10.0.0.6",
                 "ADM"


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               ],
               "node-id": "10.0.0.6",
               "ietf-te-topology:te-node-id": "10.0.0.6",
               "ietf-te-topology:te": {
                 "// comment": "TO BE COMPLETED",
                 "oper-status": "up",
                 "te-node-attributes": {
                   "name": "S6-east_end_ring-access",
                   "admin-status": "up",
                   "// __DISCUSS__ domain-id": 65001
                 },
                 "// __DISCUSS__ tunnel-termination-point": []
               },
               "ietf-network-topology:termination-point": [
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S6-1 LTP",
                     "connected to (C-R2)",
                     "unnumberd/ifIndex: 1",
                     "OTU-2",
                     "tributary port"
                   ],
                   "// comment": "S6-1 LTP",
                   "tp-id": "1",
                   "ietf-te-topology:te-tp-id": 1,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// _OBSOLETE_ ietf-otn-topology:client-facing": [
                       null
                     ],
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU2",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S6-2 LTP",
                     "connected to (C-R3)",
                     "unnumberd/ifIndex: 2",
                     "OTU-2",


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                     "tributary port"
                   ],
                   "// comment": "S6-2 LTP",
                   "tp-id": "2",
                   "ietf-te-topology:te-tp-id": 2,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// _OBSOLETE_ ietf-otn-topology:client-facing": [
                       null
                     ],
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU2",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S6-3 LTP",
                     "connected to S5-2",
                     "unnumberd/ifIndex: 3",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S6-3 LTP",
                   "tp-id": "3",
                   "ietf-te-topology:te-tp-id": 3,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 },
                 {
                   "// __DESCRIPTION__:__LTP__": [
                     "S6-4 LTP",
                     "connected to S7-2",


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                     "unnumberd/ifIndex: 4",
                     "OTU-4",
                     "line port"
                   ],
                   "// comment": "S6-4 LTP",
                   "tp-id": "4",
                   "ietf-te-topology:te-tp-id": 4,
                   "ietf-te-topology:te": {
                     "admin-status": "up",
                     "oper-status": "up",
                     "// ietf-otn-topology:supported-payload-types":
                       "__DISCUSS__",
                     "// _OBSOLETE_ ietf-otn-topology:protocol-type":
                       "ietf-transport-types:prot-OTU4",
                     "// _OBSOLETE_ ietf-otn-topology:adaptation-type":
                       "ODU"
                   }
                 }
               ]
             }
           ],
           "// ietf-network-topology:link":
             "Access links to be added in a future update.",
           "ietf-network-topology:link": [
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S1-2 to S3-2",
                 "internal link"
               ],
               "// link-id": "S1, S1-2, S3, S3-2",
               "link-id": "10.0.0.1,2,10.0.0.3,2",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "// comment": [
                     "external-domain container",
                     "not present for internal links"
                   ],
                   "name": "Link between S1 and S3",
                   "admin-status": "up",
                   "interface-switching-capability": [
                     {
                       "switching-capability":
                         "ietf-te-types:switching-otn",


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                       "encoding": "ietf-te-types:lsp-encoding-oduk",
                       "max-lsp-bandwidth": [
                         {
                           "priority": 0,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [
     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",
                                 "counter": 1
                               }
                             ]
                           }
                         },
                         {
                           "priority": 1,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [
     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",
                                 "counter": 1
                               }
                             ]
                           }
                         },
                         {
                           "priority": 2,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [
     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",
                                 "counter": 1
                               }
                             ]
                           }
                         },
                         {
                           "priority": 3,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [
     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",


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                                 "counter": 1
                               }
                             ]
                           }
                         },
                         {
                           "priority": 4,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [
     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",
                                 "counter": 1
                               }
                             ]
                           }
                         },
                         {
                           "priority": 5,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [
     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",
                                 "counter": 1
                               }
                             ]
                           }
                         },
                         {
                           "priority": 6,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [
     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",
                                 "counter": 1
                               }
                             ]
                           }
                         },
                         {
                           "priority": 7,
                           "te-bandwidth": {
                             "// _OBSOLETE_ otn": [


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     "_WARNING_ : technology specific bandwidth definition",
                               {
                                 "rate-type": "ietf-te-types:odu2",
                                 "counter": 1
                               }
                             ]
                           }
                         }
                       ]
                     }
                   ]
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S5-2 to S6-3",
                 "internal link"
               ],
               "// link-id": "S5, S5-2, S6, S6-3",
               "link-id": "10.0.0.5,2,10.0.0.6,3",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S5 and S6",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S3-3 to S4-1",
                 "internal link"
               ],
               "// link-id": "S3, S3-3, S4, S4-1",
               "link-id": "10.0.0.3,3,10.0.0.4,1",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S3 and S4",
                   "admin-status": "up"
                 }
               }


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             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S5-3 to S7-1",
                 "internal link"
               ],
               "// link-id": "S5, S5-3, S7, S7-1",
               "link-id": "10.0.0.5,3,10.0.0.7,1",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S5 and S7",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S3-4 to S5-1",
                 "internal link"
               ],
               "// link-id": "S3, S3-4, S5, S5-1",
               "link-id": "10.0.0.3,4,10.0.0.5,1",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S3 and S5",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S4-2 to S8-3",
                 "internal link"
               ],
               "// link-id": "S4, S4-2, S8, S8-3",
               "link-id": "10.0.0.4,2,10.0.0.8,3",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S4 and S8",


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                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S2-3 to S8-2",
                 "internal link"
               ],
               "// link-id": "S2, S2-3, S8, S8-2",
               "link-id": "10.0.0.2,3,10.0.0.8,2",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S2 and S8",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S8-2 to S2-3",
                 "internal link"
               ],
               "// link-id": "S8, S8-2, S2, S2-3",
               "link-id": "10.0.0.8,2,10.0.0.2,3",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S8 and S2",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S3-2 to S1-2",
                 "internal link"
               ],
               "// link-id": "S3, S3-2, S1, S1-2",
               "link-id": "10.0.0.3,2,10.0.0.1,2",
               "ietf-te-topology:te": {
                 "oper-status": "up",


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                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S3 and S1",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S7-1 to S5-3",
                 "internal link"
               ],
               "// link-id": "S7, S7-1, S5, S5-3",
               "link-id": "10.0.0.7,1,10.0.0.5,3",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S7 and S5",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S8-3 to S4-2",
                 "internal link"
               ],
               "// link-id": "S8, S8-3, S4, S4-2",
               "link-id": "10.0.0.8,3,10.0.0.4,2",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S8 and S4",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S5-1 to S3-4",
                 "internal link"
               ],
               "// link-id": "S5, S5-1, S3, S3-4",


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               "link-id": "10.0.0.5,1,10.0.0.3,4",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S5 and S3",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S2-2 to S1-1",
                 "internal link"
               ],
               "// link-id": "S2, S2-2, S1, S1-1",
               "link-id": "10.0.0.2,2,10.0.0.1,1",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S2 and S1",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S7-2 to S6-4",
                 "internal link"
               ],
               "// link-id": "S7, S7-2, S6, S6-4",
               "link-id": "10.0.0.7,2,10.0.0.6,4",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S7 and S6",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S8-4 to S7-3",


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                 "internal link"
               ],
               "// link-id": "S8, S8-4, S7, S7-3",
               "link-id": "10.0.0.8,4,10.0.0.7,3",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S8 and S7",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S6-3 to S5-2",
                 "internal link"
               ],
               "// link-id": "S6, S6-3, S5, S5-2",
               "link-id": "10.0.0.6,3,10.0.0.5,2",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S6 and S5",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S4-1 to S3-3",
                 "internal link"
               ],
               "// link-id": "S4, S4-1, S3, S3-3",
               "link-id": "10.0.0.4,1,10.0.0.3,3",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S4 and S3",
                   "admin-status": "up"
                 }
               }
             },


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             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S6-4 to S7-2",
                 "internal link"
               ],
               "// link-id": "S6, S6-4, S7, S7-2",
               "link-id": "10.0.0.6,4,10.0.0.7,2",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S6 and S7",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S1-1 to S2-2",
                 "internal link"
               ],
               "// link-id": "S1, S1-1, S2, S2-2",
               "link-id": "10.0.0.1,1,10.0.0.2,2",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S1 and S2",
                   "admin-status": "up"
                 }
               }
             },
             {
               "// __DESCRIPTION__:__LINK__": [
                 "Link from S7-3 to S8-4",
                 "internal link"
               ],
               "// link-id": "S7, S7-3, S8, S8-4",
               "link-id": "10.0.0.7,3,10.0.0.8,4",
               "ietf-te-topology:te": {
                 "oper-status": "up",
                 "te-link-attributes": {
                   "access-type": "point-to-point",
                   "name": "Link between S7 and S8",
                   "admin-status": "up"


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                 }
               }
             }
           ]
         }
       ]
     }
   }

B.2. JSON Examples for Service Configuration

B.2.1. JSON Code:  mpi1-odu2-service-config.json

   {
     "// __TITLE__": "ODU2 Service Configuration @ MPI1",
     "// __LAST_UPDATE__": "July 2, 2018",
     "// __RESTCONF_OPERATION__": {
       "operation": "PUT",
       "url": "http://{{PNC1-ADDR}}/restconf/data/ietf-te:te"
     },
     "// __REFERENCE_DRAFTS__": {
       "ietf-te-types@2018-06-12": "draft-ietf-teas-yang-te-15",
       "ietf-routing-types@2017-12-04": "rfc8294",
       "ietf-te@2018-06-12": "draft-ietf-teas-yang-te-15",
       "ietf-otn-types@2018-06-07":
         "draft-ietf-ccamp-otn-tunnel-model-02",
       "ietf-otn-tunnel@2018-06-07":
         "draft-ietf-ccamp-otn-tunnel-model-02"
     },
     "// __MISSING_ATTRIBUTES__": true,
     "ietf-te:te": {
       "tunnels": {
         "tunnel": [
           {
             "name": "mpi1-odu2-service",
             "// identifier": "ODU2-SERVICE-TUNNEL-ID @ MPI1",
             "identifier": 1,
             "description":
          "ODU2 Service implemented by ODU2 OTN Tunnel Segment @ MPI1",
             "// encoding and switching-type": "ODU",
             "encoding": "ietf-te-types:lsp-encoding-oduk ",
             "switching-type": "ietf-te-types:switching-otn",
             "// source": "None: transit tunnel segment",
             "// destination": "None: transit tunnel segment",
             "// src-tp-id": "None: transit tunnel segment",


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             "// dst-tp-id": "None: transit tunnel segment",
             "// __ ACTION __ ietf-otn-tunnel:payload-treatment": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "ietf-otn-tunnel:src-client-signal":
              "ietf-otn-types:client-signal-ODU2",
             "// __ ACTION __ src-tpn": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "// __ ACTION __ src-tsg": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "// __ ACTION __ src-tributary-slot-count": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "// __ ACTION __ src-tributary-slots": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "ietf-otn-tunnel:dst-client-signal":
              "ietf-otn-types:client-signal-ODU2",
             "// __ ACTION __ dst-tpn": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "// __ ACTION __ dst-tsg": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "// __ ACTION __ dst-tributary-slot-count": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "// __ ACTION __ dst-tributary-slots": [
             "This attribute should be removed in the next otn-tunnel",
              " model update"
             ],
             "bidirectional": true,
             "// __ DEFAULT __ protection": {
               "// __ DEFAULT __ enable": false
             },


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             "// __ DEFAULT __ restoration": {
               "// __ DEFAULT __ enable": false
             },
             "// __ DISCUSS __ te-topology-identifier": [
             "Need to add the te-topology-identifier",
             "information. Waiting for updates to topology identifiers"
             ],
             "te-bandwidth": {
               "ietf-otn-tunnel:odu-type": "ietf-otn-types:prot-ODU2"
             },
             "// hierarchical-link":
              "Not to be specified: transit tunnel segment",
             "p2p-primary-paths": {
               "p2p-primary-path": [
                 {
                   "name": "mpi1-odu2-tunnel-primary-path",
                   "// __ DISCUSS __ path-scope": [
                   "Need to align the model based on the on-going",
                    " disucssion of the related open issue"
                   ],
                   "path-scope": "ietf-te-types:path-scope-segment",
                   "// te-bandwidth": [
               "None: only the tunnel bandwidth needs to be specified",
                    " in transport applications"
                   ],
                   "explicit-route-objects": {
                     "route-object-include-exclude": [
                       {
                         "// comment":
                       "Tunnel hand-off OTU2 ingress interface (S3-1)",
                         "index": 1,
                         "explicit-route-usage":
                          "ietf-te-types:route-include-ero",
                         "num-unnum-hop": {
                           "// node-id": "S3-NODE-ID",
                           "node-id": "10.0.0.3",
                           "// link-tp-id": "S3-1-LTP-ID",
                           "link-tp-id": 1,
                           "hop-type": "STRICT",
                           "direction": "INCOMING"
                         }
                       },
                       {
                         "// comment": [
                       "Tunnel hand-off ODU2 ingress label (ODU2 over",


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                          " OTU2) at S3-1"
                         ],
                         "index": 2,
                         "explicit-route-usage":
                          "ietf-te-types:route-include-ero",
                         "label-hop": {
                           "te-label": {
                             "// __ DISCUSS __ odu-label": [
                             "How are HO-ODU (ODUk voer OTUk) label",
                              " represented?"
                             ],
                             "// __ ACTION __ direction":
                              "Check with TE Tunnel authors",
                             "direction": "FORWARD "
                           }
                         }
                       },
                       {
                         "// comment":
                        "Tunnel hand-off OTU4 egress interface (S2-1)",
                         "index": 3,
                         "explicit-route-usage":
                          "ietf-te-types:route-include-ero",
                         "num-unnum-hop": {
                           "// node-id": "S2-NODE-ID",
                           "node-id": "10.0.0.2",
                           "// link-tp-id": "S2-1-LTP-ID",
                           "link-tp-id": 1,
                           "hop-type": "STRICT",
                           "direction": "OUTGOING"
                         }
                       },
                       {
                         "// comment": [
                        "Tunnel hand-off ODU2 egress label (ODU2 over",
                          " OTU4) at S2-1"
                         ],
                         "index": 4,
                         "explicit-route-usage":
                          "ietf-te-types:route-include-ero",
                         "label-hop": {
                           "te-label": {
                             "ietf-otn-tunnel:tpn": 1,
                             "ietf-otn-tunnel:tsg":
                              "ietf-otn-types:tsg-1.25G",


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                             "ietf-otn-tunnel:ts-list": "1-8",
                             "// __ ACTION __ direction":
                              "Check with TE Tunnel authors",
                             "direction": "FORWARD "
                           }
                         }
                       }
                     ]
                   }
                 }
               ]
             }
           }
         ]
       }
     }
   }

B.2.2. JSON Code: mpi1-odu2-tunnel-config.json

   {
     "// __TITLE__": "ODU2 Tunnel Configuration @ MPI1",
     "// __LAST_UPDATE__": "July 2, 2018",
     "// __RESTCONF_OPERATION__": {
       "operation": "PUT",
       "url": "http://{{PNC1-ADDR}}/restconf/data/ietf-te:te"
     },
     "// __REFERENCE_DRAFTS__": {
       "ietf-te-types@2018-06-12": "draft-ietf-teas-yang-te-15",
       "ietf-routing-types@2017-12-04": "rfc8294",
       "ietf-te@2018-06-12": "draft-ietf-teas-yang-te-15",
       "ietf-otn-types@2018-06-07":
         "draft-ietf-ccamp-otn-tunnel-model-02",
       "ietf-otn-tunnel@2018-06-07":
         "draft-ietf-ccamp-otn-tunnel-model-02"
     },
     "// __MISSING_ATTRIBUTES__": true,
     "ietf-te:te": {
       "tunnels": {
         "tunnel": [
           {
             "name": "mpi1-odu2-tunnel",
             "// identifier": "ODU2-TUNNEL-ID @ MPI1",
             "identifier": 2,
             "description":


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              "TNBI Example for an ODU2 Head Tunnel Segment @ MPI1",
             "// encoding and switching-type": "ODU",
             "encoding": "ietf-te-types:lsp-encoding-oduk ",
             "switching-type": "ietf-te-types:switching-otn",
             "source": "10.0.0.3",
             "// destination": "None: head tunnel segment",
             "src-tp-id": "AAAB",
             "// dst-tp-id": "None: head tunnel segment",
             "ietf-otn-tunnel:src-client-signal":
              "ietf-otn-types:client-signal-ODU2",
             "ietf-otn-tunnel:dst-client-signal":
              "ietf-otn-types:client-signal-ODU2",
             "bidirectional": true,
             "// __ DEFAULT __ protection": {
               "// __ DEFAULT __ enable": false
             },
             "// __ DEFAULT __ restoration": {
               "// __ DEFAULT __ enable": false
             },
             "// __ DISCUSS __ te-topology-identifier":
              "Need to add the te-topology-identifier information",
             "te-bandwidth": {
               "ietf-otn-tunnel:odu-type": "ietf-otn-types:prot-ODU2"
             },
             "// __ DISCUSS __ hierarchical-link":
     "Optional: tunnel supports service, not link in the client layer",
             "p2p-primary-paths": {
               "p2p-primary-path": [
                 {
                   "name": "mpi1-odu2-tunnel-primary-path",
                   "// __ DISCUSS __ path-scope":
                    "Need to align the model",
                   "path-scope": "ietf-te-types:path-scope-segment",
                   "// te-bandwidth":
                 "None: only the tunnel bandwidth needed in transport",
                   "explicit-route-objects": {
                     "route-object-include-exclude": [
                       {
                         "// comment": "Tunnel TTP in node S3",
                         "index": 1,
                         "explicit-route-usage":
                          "ietf-te-types:route-include-ero",
                         "num-unnum-hop": {
                           "// node-id": "S3-NODE-ID",
                           "node-id": "10.0.0.3",


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                           "hop-type": "STRICT",
                           "// __ ACTION __ direction":
                            "Check with TE Tunnel authors",
                           "direction": "OUTGOING"
                         }
                       },
                       {
                         "// comment":
                        "Tunnel hand-off OTU4 egress interface (S2-1)",
                         "index": 2,
                         "explicit-route-usage":
                          "ietf-te-types:route-include-ero",
                         "num-unnum-hop": {
                           "// node-id": "S2-NODE-ID",
                           "node-id": "10.0.0.2",
                           "// link-tp-id": "S2-1-LTP-ID",
                           "link-tp-id": 1,
                           "hop-type": "STRICT",
                           "direction": "OUTGOING"
                         }
                       },
                       {
                         "// comment":
          "Tunnel hand-off ODU2 egress label (ODU2 over OTU4) at S2-1",
                         "index": 3,
                         "explicit-route-usage":
                          "ietf-te-types:route-include-ero",
                         "label-hop": {
                           "te-label": {
                             "ietf-otn-tunnel:tpn": 2,
                             "ietf-otn-tunnel:tsg":
                              "ietf-otn-types:tsg-1.25G",
                             "ietf-otn-tunnel:ts-list": "9-16",
                             "// __ ACTION __ direction":
                              "Check with TE Tunnel authors",
                             "direction": "FORWARD "
                           }
                         }
                       }
                     ]
                   }
                 }
               ]
             }
           }


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         ]
       }
     }
   }

B.2.3. JSON Code: mpi1-epl-service-config.json

   {
     "// __TITLE__": "EPL Configuration @ MPI1",
     "// __LAST_UPDATE__": "July 2, 2018",
     "// __RESTCONF_OPERATION__": {
       "operation": "PUT",
       "url":
    "http://{{PNC1}}/restconf/data/ietf-trans-client-service:etht-svc"
     },
     "// __REFERENCE_DRAFTS__": {
       "ietf-te-types@2018-03-05": "draft-ietf-teas-yang-te-14",
       "ietf-eth-tran-types@2018-03-01":
         "draft-zheng-ccamp-otn-client-signal-yang-02",
       "ietf-routing-types@2017-12-04": "rfc8294",
       "ietf-eth-tran-service@2018-03-01":
         "draft-zheng-ccamp-otn-client-signal-yang-02"
     },
     "// __MISSING_ATTRIBUTES__": true,
     "ietf-eth-tran-service:etht-svc": {
       "etht-svc-instances": [
         {
           "etht-svc-name": "mpi1-epl-service",
           "etht-svc-descr":
             "TNBI Example for an EPL over ODU2 Service @ MPI1",
           "// __ DEFAULT __ etht-svc-type": "p2p-svc",
           "// __ DISCUSS __ te-topology-identifier": [
            "Would it be possible to use this grouping instead of",
             " re-defining the three attributes below?"
           ],
           "// __ ACTION __ access-provider-id":
             "Need to add the te-topology-identifier information",
           "// __ ACTION __ access-client-id":
             "Need to add the te-topology-identifier information",
           "// __ ACTION __ topology-id":
             "Need to add the te-topology-identifier information",
           "etht-svc-access-ports": [
             {
               "// comment": "10GE access interface (S3-1)",
               "access-port-id": 1,


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               "// access-node-id": "S3-NODE-ID",
               "access-node-id": "10.0.0.3",
               "// access-ltp-id": "S3-1-LTP-ID",
               "access-ltp-id": 1,
               "service-classification-type":
                 "ietf-eth-tran-types:port-classification",
              "// __ DISCUSS __ ingress-egress-bandwidth-profile-name":
                 "10G-EPL-BWP",
               "// vlan-operations":
                 "None: transparent VLAN operations"
             }
           ],
           "etht-svc-tunnels": [
             {
               "tunnel-name": "mpi1-odu2-tunnel"
             }
           ],
           "admin-status": "ietf-te-types:tunnel-state-up"
         }
       ]
     }
   }

























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   Authors' Addresses

   Italo Busi (Editor)
   Huawei

   Email: italo.busi@huawei.com


   Daniel King (Editor)
   Lancaster University

   Email: d.king@lancaster.ac.uk


   Haomian Zheng (Editor)
   Huawei

   Email: zhenghaomian@huawei.com


   Yunbin Xu (Editor)
   CAICT

   Email: xuyunbin@ritt.cn


   Yang Zhao
   China Mobile

   Email: zhaoyangyjy@chinamobile.com


   Sergio Belotti
   Nokia

   Email: sergio.belotti@nokia.com


   Gianmarco Bruno
   Ericsson

   Email: gianmarco.bruno@ericsson.com





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   Young Lee
   Huawei

   Email: leeyoung@huawei.com


   Victor Lopez
   Telefonica

   Email: victor.lopezalvarez@telefonica.com


   Carlo Perocchio
   Ericsson

   Email: carlo.perocchio@ericsson.com


   Ricard Vilalta
   CTTC

   Email: ricard.vilalta@cttc.es

























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