TEAS WG                                                       Young Lee
                                                            Dhruv Dhody
Internet Draft                                                   Huawei
Intended status: standard
                                                    Daniele Ceccarrelli
Expires: September 2017                                        Ericsson



-

                                                          March 9, 2017



           Traffic Engineering and Service Mapping Yang Model
                 draft-lee-teas-te-service-mapping-yang-00

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   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


   This document provides a YANG data model to map service model (e.g.
   L3SM) and Traffic Engineering model (e.g. TE Tunnel or ACTN VN
   model). This model is referred to as TE service Mapping Model. This
   model is applicable to the operation's need for a seamless control
   and management of their L3VPN with TE tunnel support.


Table of Contents


   1. Introduction...................................................2
   2. L3VPN Architecture in ACTN context.............................4
   3. TE-Service Mapping Model.......................................7
   4. YANG Data Tree.................................................7
   5. Yang Data Model................................................9
   6. Security......................................................16
   7. Acknowledgements..............................................16
   8. References....................................................17
      8.1. Informative References...................................17
   9. Contributors..................................................18
   Authors' Addresses...............................................18

1. Introduction

   Data models are a representation of objects that can be configured
   or monitored within a system. Within the IETF, YANG [RFC6020] is the
   language of choice for documenting data models, and YANG models have
   been produced to allow configuration or modeling of a variety of
   network devices, protocol instances, and network services. YANG data
   models have been classified in [Netmod-Yang-Model-Classification]
   and [Service-YANG].

   [RFC4110] provides a framework for Layer 3 Provider-Provisioned
   Virtual Private Networks (PPVPNs). [L3SM-YANG] provides a L3VPN
   service delivery YANG model for PE-based VPNs.



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   [ACTN-VN-YANG] describes how customers or end to end orchestrators
   can request and/or instantiate a generic virtual network service.
   [ACTN-Applicability] describes a connection between IETF YANG model
   classifications to ACTN interfaces. In particular, it describes the
   customer service model can be mapped into the CMI (CNC-MDSC
   Interface) of the ACTN architecture.

   The YANG model on the ACTN CMI is known as customer service model in
   [Service-YANG]. The YANG model developed in this document describes
   how operator's end to end orchestrator interacts with the MDSC so
   that the MDSC then can coordinate the control and management of
   L3VPN MPLS TE tunnels that traverse both IP/MPLS and Transport
   networks.

   While IP/MPLS PNC is responsible for provisioning the VPN service on
   the PE nodes, the MDSC can coordinate how to map the VPN services
   with TE tunnels. This is consistent with the two of the core
   functions of the MDSC specified in [ACTN-Frame]:

     . Customer mapping/translation function: This function is to map
        customer requests/commands into network provisioning requests
        that can be sent to the Physical Network Controller (PNC)
        according to business policies provisioned statically or
        dynamically. Specifically, it provides mapping and translation
        of a customer's service request into a set of parameters that
        are specific to a network type and technology such that network
        configuration process is made possible.

     . Virtual service coordination function: This function translates
        customer service-related information into virtual network
        service operations in order to seamlessly operate virtual
        networks while meeting a customer's service requirements. In
        the context of ACTN, service/virtual service coordination
        includes a number of service orchestration functions such as
        multi-destination load balancing, guarantees of service
        quality, bandwidth and throughput. It also includes
        notifications for service fault and performance degradation and
        so forth.


   In some cases, under the confines of service policy, dynamic TE
   tunnel creation may need to be supported for the VPN service. This
   may occur when there are no suitable existing TE tunnels that can
   support VPN service requirements. Or the operator would like to
   dynamically create and bind tunnels to the VPN, which could not be
   shared for network slicing.



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   To summarize there are two mode of operations -

   . VN/Tunnel Binding - Customer could use the VPN service model
     [L3SM-Yang] to communicate to the network operator to deliver
     a L3VPN service. Based on the sites, QoS parameters, VPN service
     topology, the network operator could create an ACTN VN [ACTN-VN-
     YANG]. Further the mapping yang model described in Section 5 of
     this document is used to set this mapping between the L3VPN
     service and the ACTN VN. Note that this could be done dynamically.
     The VN (and TE tunnels) could be bound to the L3VPN and not used
     for any other VPN.


   . VN/Tunnel Selection - Customer could request an L3VPN service
     [L3SM-Yang], and with this model as input, the PNC configures the
     different network elements to deliver the service. Each network
     element would select a tunnel based on the configuration. With
     this mode, new tunnels (or VN) are not created for each VPN. Thus,
     the tunnels can be shared across multiple VPN. Further the mapping
     yang model described in Section 5 of this document is used to get
     the mapping between the L3VPN and the tunnels in use.

   The YANG model described in this document provides an ACTN TE-
   service mapping model that enables a seamless service mapping across
   L3VPN, ACTN VN and TE-tunnel models at the controllers.

2. L3VPN Architecture in ACTN context

   Figure 1 shows the architectural context of this document.




















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                                       | L3SM (+CMI)
                                     V
                                  +------+
                                  | MDSC |
                                  +------+
                                     |
                            +-------------------------------+
                            |               |               |
                            V               V               V
                         +--------+     +--------+    +--------+
                         |IP/MPLS |     | Transp.|    |IP/MPLS |
                         |  PNC 1 |     |   PNC  |    |  PNC 2 |
                         +--------+     +--------+    +--------+

                   CE                                                   CE
                    \     AS 100                          AS 200       /
                     \                                               /
                      A----B----C----ASBR1------ASBR2----D----E----F
                     /:   /    /:      /:         /:    /:   /:   /:
                    / :  /    / :     / :        / :   / :  / :  / :
             CE----G--:-H----I--:-ASBR3-:----ASBR4-:--J--:-K--:-L--:---CE
                   :  : :    :  :   :   :      :   :     : :  : :  :
                   :  : :    :  :   :   :      :   :     : :  : :  :
                   :  : :    :  :   :   :      :   :     : :  : :  :
                   :  M-:----:--P---:---S------:---U-----V-:--X-:--Y
                   : /  :    : /    :  /       :  /        : /  : /
                   :/   :    :/     : /        : /         :/   :/
                   N----O----Q-------R----------T----------W----Z
                                    Transport Network


        Figure 1: L3VPN Architecture from the IP+Optical Network Perspective



   There are three main entities in the architecture.

  . MDSC: This entity is responsible for coordinating a L3VPN service
     request (expressed in L3SM) with the IP PNC and the Transport PNC.
     One of the key responsibilities of the MDSC for TE services is to
     coordinate with both the IP PNC and the Transport PNC for the
     mapping of L3VPN Service Model and ACTN VN/TE-Tunnel models. With
     the VN/TE-tunnel binding case, the MDSC will need to coordinate
     with the Transport PNC to dynamically create the TE-tunnel(s) in
     the Transport network as needed. These tunnels are added as links
     in the IP Layer topology. The MDSC coordinates with IP PNC to



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     create the TE-tunnel(s) in the IP layer, as part of the ACTN VN
     creation.

  . IP/MPLS PNC: This entity is responsible for device configuration
     to create PE-PE L3VPN tunnels for the VPN customer and for the
     configuration of the L3VPN VRF on the PE nodes. Each network
     element would select a tunnel based on the configuration.

  . Transport PNC: This entity is responsible for device configuration
     for TE tunnels in the transport networks.

   High-Level Control Flows

     1. Customer asks for a L3VPN between CE1 and CE2 with TE
        constraints using L3SM model. The customer can provide tunnel
        creation policy where it allows dynamic VN/TE tunnel creation
        or not. Under this policy, dynamic VN/TE tunnels can be created
        when there are no proper VN/TE-tunnels that can support L3VPN
        tunnels or when there is a strict isolation requirement for the
        VPN service, e.g., no sharing with other tunnels is allowed.

     2. The MDSC determines if it needs to create a new VN, and if that
        is the case, ACTN VN YANG [ACTN-VN-YANG] is used to configure a
        new VN based on this VPN and map the VPN service to ACTN VN. In
        case an existing tunnel is to be used, each device will select
        which tunnel to use and populates this mapping information.

     3. The MDSC interacts with both the IP/MPLS PNC and the Transport
        PNC to create a PE-PE tunnel in the IP network mapped to a TE
        tunnel in the transport network by providing the inter-layer
        access points and tunnel requirements. The specific service
        information are passed to the IP/MPLS PNC for the actual VPN
        configuration and activation.

          a. The Transport PNC creates the corresponding TE tunnel
             matching with the access point and egress point.
          b. The IP/MPLS PNC maps the VPN ID with the corresponding TE
             tunnel ID to bind these two IDs.

     4. The IP/MPLS PNC creates/updates a VRF instance for this VPN
        customer. (This is not covered by the Yang Model presented in
        this draft).







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3. TE-Service Mapping Model

   The role of TE-service Mapping model is to create a binding
   relationship across L3SM and TE Tunnel model via generic ACTN VN
   Model. The ACTN VN YANG model is a generic virtual network service
   model that allows customers (internal or external) to create a VN
   that meets the customer's service objective with various
   constraints. The TE-service mapping model is needed to bind L3VPN
   specific service model with TE-specific parameters. This binding
   will facilitate a seamless service operation with underlay-TE
   network visibility. The TE-service model developed in this document
   can also be extended to support other services such as L2SM and so
   one.


         +---------+          +-------------+         +----------+
         |  L3SM   | <------> |             | <-----> | TE-Tunnel|
         +---------+          |             |         |  Model   |
                              | TE-Service  |         +-----^----+
                              |Mapping Model|               |
         +---------+          |             |         +-----v----+
         |  L2SM   | <------> |             | <-----> | ACTN VN  |
         +---------+          +-------------+         |  Model   |
                                                      +----------+



            . . .



4. YANG Data Tree

   module: ietf-te-service-mapping
       +--rw te-service-mapping
       |  +--rw service-mapping
       |  |  +--rw mapping-list* [map-id]
       |  |     +--rw map-id            uint32
       |  |     +--rw map-type?         map-type
       |  |     +--rw (service)?
       |  |     |  +--:(l3vpn)
       |  |     |  |  +--rw l3vpn-ref?        -> /l3:l3vpn-svc/vpn-services/vpn-
   service/vpn-id
       |  |     |  +--:(l2vpn)
       |  |     |     +--rw l2vpn-ref?        -> /l2:l2vpn-svc/vpn-services/vpn-
   svc/vpn-id


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       |  |     +--rw (te)?
       |  |        +--:(actn-vn)
       |  |        |  +--rw actn-vn-ref?      -> /vn:actn/vn/vn-list/vn-id
       |  |        +--:(te)
       |  |           +--rw te-tunnel-list*   te:tunnel-ref
       |  +--rw site-mapping
       |     +--rw mapping-list* [map-id]
       |        +--rw map-id         uint32
       |        +--rw (service)?
       |        |  +--:(l3vpn)
       |        |  |  +--rw l3vpn-ref?     -> /l3:l3vpn-svc/sites/site/site-id
       |        |  +--:(l2vpn)
       |        |     +--rw l2vpn-ref?     -> /l2:l2vpn-svc/sites/site/site-id
       |        +--rw (te)?
       |           +--:(actn-vn)
       |           |  +--rw actn-vn-ref?   -> /vn:actn/ap/access-point-list/access-
   point-id
       |           +--:(te)
       +--ro te-service-mapping-state
          +--ro service-mapping
          |  +--ro mapping-list* [map-id]
          |     +--ro map-id            uint32
          |     +--ro map-type?         map-type
          |     +--ro (service)?
          |     |  +--:(l3vpn)
          |     |  |  +--ro l3vpn-ref?        -> /l3:l3vpn-svc/vpn-services/vpn-
   service/vpn-id
          |     |  +--:(l2vpn)
          |     |     +--ro l2vpn-ref?        -> /l2:l2vpn-svc/vpn-services/vpn-
   svc/vpn-id
          |     +--ro (te)?
          |        +--:(actn-vn)
          |        |  +--ro actn-vn-ref?      -> /vn:actn/vn/vn-list/vn-id
          |        +--:(te)
          |           +--ro te-tunnel-list*   te:tunnel-ref
          +--ro site-mapping
             +--ro mapping-list* [map-id]
                +--ro map-id         uint32
                +--ro (service)?
                |  +--:(l3vpn)
                |  |  +--ro l3vpn-ref?     -> /l3:l3vpn-svc/sites/site/site-id
                |  +--:(l2vpn)
                |     +--ro l2vpn-ref?     -> /l2:l2vpn-svc/sites/site/site-id
                +--ro (te)?
                   +--:(actn-vn)
                   |  +--ro actn-vn-ref?   -> /vn:actn/ap/access-point-list/access-
   point-id
                   +--:(te)



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5. Yang Data Model

   The YANG code is as follows:

   <CODE BEGINS> file "ietf-te-service-mapping@2017-03-09.yang"

   module ietf-te-service-mapping {

       namespace "urn:ietf:params:xml:ns:yang:ietf-te-service-mapping";

       prefix "tm";

       import ietf-l3vpn-svc {
           prefix "l3";
       }

       import ietf-l2vpn-svc {
           prefix "l2";
       }

       import ietf-te {
           prefix "te";
       }

       import ietf-actn-vn {
           prefix "vn";
       }


       organization
           "IETF Traffic Engineering Architecture and Signaling (TEAS)
           Working Group";

       contact
           "Editor: Young Lee <leeyoung@huawei.com>
                    Dhruv Dhody <dhruv.ietf@gmail.com>";

       description
           "This module contains a YANG module for the mapping of
           service (e.g. L3VPN) to the TE tunnels or ACTN VN.";



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       revision 2017-03-09 {
           description
               "initial version.";
           reference
               "TBD";
       }

       /*
        * Identities
        */
       identity service-type {
           description
               "Base identity from which specific service types are
               derived.";
       }

       identity l3vpn-service {
           base service-type;
           description
               "L3VPN service type.";
       }

       identity l2vpn-service {
           base service-type;
           description
               "L2VPN service type.";
       }


       /*
        * Enum
        */
       typedef map-type {
           type enumeration {
               enum "bind" {
                   description
                       "The VN/tunnels are binded to the service";
               }
               enum "select" {
                   description
                       "The VPN service select an existing tunnel";


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               }
           }
           description
               "The map-type";
       }

       /*
        * Groupings
        */
       grouping service-ref{
           description
               "The reference to the service.";
            choice service {
               description
                   "The service";
               case l3vpn {
                   leaf l3vpn-ref {
                       type leafref {
                           path "/l3:l3vpn-svc/l3:vpn-services/"
                           + "l3:vpn-service/l3:vpn-id";
                       }
                       description
                           "The reference to L3VPN Service Yang Model";
                   }
               }
               case l2vpn {
                   leaf l2vpn-ref {
                       type leafref {
                           path "/l2:l2vpn-svc/l2:vpn-services/"
                           + "l2:vpn-svc/l2:vpn-id";
                       }
                       description
                           "The reference to L2VPN Service Yang Model";
                   }

               }

            }
       }

       grouping site-ref {


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           description
               "The reference to the site.";
            choice service {
               description
                   "The service choice";
               case l3vpn {
                   leaf l3vpn-ref{
                       type leafref {
                           path "/l3:l3vpn-svc/l3:sites/l3:site/"
                           + "l3:site-id";
                       }
                       description
                           "The reference to L3VPN Service Yang Model";
                   }
               }
               case l2vpn {
                   leaf l2vpn-ref{
                       type leafref {
                           path "/l2:l2vpn-svc/l2:sites/l2:site/"
                           + "l2:site-id";
                       }
                       description
                           "The reference to L2VPN Service Yang Model";
                   }

               }

            }
       }

       grouping te-ref {
           description
               "The reference to TE.";
           choice te {
               description
                   "The TE";
               case actn-vn {
                   leaf actn-vn-ref {
                       type leafref {
                           path "/vn:actn/vn:vn/vn:vn-list/vn:vn-id";
                       }


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                       description
                           "The reference to ACTN VN";
                   }
               }
               case te {
                   leaf-list te-tunnel-list {
                       type te:tunnel-ref;
                       description
                           "Reference to TE Tunnels";
                   }
               }

           }

       }

       grouping te-endpoint-ref {
           description
               "The reference to TE endpoints.";
           choice te {
               description
                   "The TE";
               case actn-vn {
                   leaf actn-vn-ref {
                       type leafref {
                           path "/vn:actn/vn:ap/vn:access-point-list"
                           + "/vn:access-point-id";
                       }
                       description
                           "The reference to ACTN VN";
                   }
               }
               case te {
                   /*should we refer to Te-topology or Te-tunnel's
   endpoint(?)*/
               }

           }

       }



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       grouping service-mapping {
           description
               "Mapping between Services and TE";
           container service-mapping {
               description
                   "Mapping between Services and TE";

               list mapping-list {
                   key "map-id";
                   description
                       "Mapping identified via a map-id";
                   leaf map-id {
                       type uint32;
                       description
                           "a unique mapping identifier";
                   }
                   leaf map-type {
                       type map-type;
                       description
                           "Tunnel Bind or Tunnel Selection";
                   }
                   uses service-ref;

                   uses te-ref;
               }
           }
       }
       grouping site-mapping {
           description
               "Mapping between VPN access site and TE
               endpoints or AP";
           container site-mapping {
               description
                   "Mapping between VPN access site and TE
                   endpoints or AP";
               list mapping-list {
                   key "map-id";
                   description
                       "Mapping identified via a map-id";
                   leaf map-id {
                       type uint32;


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                       description
                           "a unique mapping identifier";
                   }
                   uses site-ref;

                   uses te-endpoint-ref;
               }

           }
       }




       /*
        * Configuration data nodes
        */
       container te-service-mapping {
           description
               "Mapping between Services and TE";


           uses service-mapping;

           uses site-mapping;
       }

       /*
        * Operational data nodes
        */

       container te-service-mapping-state{
           config false;

           description
               "Mapping between Services and TE";

           uses service-mapping;

           uses site-mapping;
       }


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   }

   <CODE ENDS>


6. Security

   This document is an informational draft. When the models mentioned
   in this draft are implemented, detailed security consideration will
   be given in such work.

   How security fits into the whole architecture has the following
   components:

   - the use of Restconf security between components

   - the use of authentication and policy to govern which services can
   be requested by different parties.

   - how security may be requested as an element of a service and
   mapped down to protocol security mechanisms as well as separation
   (slicing) of physical resources)


7. IANA Considerations


   This document registers the following namespace URIs in the IETF XML
   registry [RFC3688]:

   --------------------------------------------------------------------
   URI: urn:ietf:params:xml:ns:yang:ietf-te-service-mapping
   Registrant Contact: The IESG.
   XML: N/A, the requested URI is an XML namespace.
   --------------------------------------------------------------------

   This document registers the following YANG modules in the YANG
   Module

   Names registry [RFC7950]:

   --------------------------------------------------------------------



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   name:         ietf-service-mapping
   namespace:    urn:ietf:params:xml:ns:yang:ietf-te-service-mapping
   prefix:       rip
   reference:    RFC XXXX (TDB)
   --------------------------------------------------------------------


8. Acknowledgements

   We thank Diego Caviglia and Igor Bryskin for useful discussions and
   motivation for this work.

9. References

9.1. Informative References

   [RFC4110] R. Callon and M. Suzuki, "A Framework for Layer 3
             Provider-Provisioned Virtual Private Networks (PPVPNs)",
             RFC 4110, July 2005.

   [RFC6020] M. Bjorklund, Ed., "YANG - A Data Modeling Language for
             the Network Configuration Protocol (NETCONF)", RFC 6020,
             October 2010.

   [Service-YANG] Q. Wu, W. Liu and A. Farrel, "Service Models
             Explained", draft-wu-opsawg-service-model-explained, work
             in progress.

   [Netmod-Yang-Model-Classification] D. Bogdanovic, B. Claise, and C.
             Moberg, "YANG Module Classification", draft-ietf-netmod-
             yang-model-classification, work in progress.

   [Netconf] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
             and A. Bierman, Ed., "Network Configuration Protocol
             (NETCONF)", RFC 6241.

   [Restconf] A. Bierman, M. Bjorklund, and K. Watsen, "RESTCONF
             Protocol", draft-ietf-netconf-restconf, work in progress.

   [ACTN-Frame] D. Cecarelli and Y. Lee, "Framework for Abstraction and
             Control of Traffic Engineered Networks", draft-ietf-teas-
             actn-framework, work in progress.

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



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   [TE-Tunnel] T. Saad (Editor), "A YANG Data Model for Traffic
             Engineering Tunnels and Interfaces", draft-ietf-teas-yang-
             te, work in progress.

   [ACTN-VN-YANG] Y. Lee (Editor), "A Yang Data Model for ACTN VN
             Operation", draft-lee-teas-actn-vn-yang, work in progress.

   [L3SM-YANG] S. Litkowski, L.Tomotaki, and K. Ogaki, "YANG Data Model
             for L3VPN service delivery", draft-ietf-l3sm-l3vpn-
             service-model, work in progress.





10. Contributors


Authors' Addresses

   Young Lee
   Huawei Technologies
   5340 Legacy Drive
   Plano, TX 75023, USA
   Phone: (469)277-5838

   Email: leeyoung@huawei.com

   Dhruv Dhody
   Huawei Technologies

   Email: dhruv.ietf@gmail.com

   Daniele Ceccarelli
   Ericsson
   Torshamnsgatan,48
   Stockholm, Sweden

   Email: daniele.ceccarelli@ericsson.com









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