Network Working Group                                             X. Liu
Internet-Draft                                       Kuatro Technologies
Intended status: Standards Track                              I. Bryskin
Expires: May 3, 2017                                 Huawei Technologies
                                                               V. Beeram
                                                        Juniper Networks
                                                                 T. Saad
                                                       Cisco Systems Inc
                                                                 H. Shah
                                                                   Ciena
                                                            S. Litkowski
                                                 Orange Business Service
                                                        October 30, 2016


               YANG Data Model for Layer 3 TE Topologies
                   draft-liu-teas-yang-sr-te-topo-01

Abstract

   This document defines a YANG data model for Segment Routing (SR)
   topology and Segment Routing (SR) traffic engineering (TE) topology.

Status of This Memo

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

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

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

   This Internet-Draft will expire on May 3, 2017.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of



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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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Modeling Considerations . . . . . . . . . . . . . . . . . . .   3
     2.1.  Segment Routing (SR) topology . . . . . . . . . . . . . .   3
     2.2.  Segment Routing (SR) TE topology  . . . . . . . . . . . .   3
     2.3.  Relations to ietf-segment-routing . . . . . . . . . . . .   4
     2.4.  Open Items  . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Model Structure . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  YANG Module . . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   This document defines a YANG [RFC7950]  data model for describing the
   presentations of Segment Routing (SR) topology and Segment Routing
   (SR) traffic engineering (TE) topology.

1.1.  Terminology

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

   The following terms are defined in [RFC7950] and are not redefined
   here:

   o  augment

   o  data model

   o  data node





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2.  Modeling Considerations

2.1.  Segment Routing (SR) topology

   The Layer 3 network topology model is discussed in
   [I-D.ietf-i2rs-yang-l3-topology].  The Segment Routing (SR) topology
   model proposed in this document augments and uses the ietf-l3-
   unicast-igp-topology module defined in
   [I-D.ietf-i2rs-yang-l3-topology].  SR related attributes are covered
   in the ietf-sr-topology model.

               +------------------------------+
               |   Layer 3 Network Topology   |
               |   ietf-l3-unicast-topology   |
               +------------------------------+
                               |
                               |
                               |
                               V
                  +------------------------+
                  |       SR Topology      |
                  |     ietf-sr-topology   |
                  +------------------------+

2.2.  Segment Routing (SR) TE topology

   When traffic engineering is enabled on an SR topology, there will be
   associations between objects in SR topologies and objects in TE
   topologies.  An SR TE topology is both an SR topology and a layer 3
   TE topology.  Multiple inheritance is used to achieve such relations.

          +------------------+  +---------------------+
          | SR Topology      |  | L3 TE Topology      |
          | ietf-sr-topology |  | ietf-l3-te-topology |
          +------------------+  +---------------------+
                   \                      /
                    \                    /
                     \                  /
                      v                v
                  +------------------------+
                  |      SR TE Topology    |
                  |                        |
                  +------------------------+

   Each type of topologies is indicated by "network-types" defined in
   [I-D.ietf-i2rs-yang-network-topo].  For the three types of topologies
   above, the data representations are:




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   L3 Topology:

   /nw:networks/nw:network/nw:network-types/l3-unicast-topology

   L3 TE Topology:

   /nw:networks/nw:network/nw:network-types/l3-unicast-topology/l3-te

   SR Topology:

   /nw:networks/nw:network/nw:network-types/l3-unicast-topology/sr

   SR TE Topology: (multiple inheritance)

   /nw:networks/nw:network/nw:network-types/l3-unicast-topology/l3-te
   /nw:networks/nw:network/nw:network-types/l3-unicast-topology/sr

2.3.  Relations to ietf-segment-routing

   [I-D.ietf-spring-sr-yang]defines ietf-segment-routing that is a model
   intended to be used on network elements to configure or operate
   segment routing; ietf-sr-topology defined in this document is
   intended to be used on a controller for the network-wide operations
   such as path computation.

   SR topology model shares many modeling constructs defined in ietf-
   segment-routing.  The module ietf-sr-topology uses the types and
   groupings defined in ietf-segment-routing.

2.4.  Open Items

   a.  Protection on link: The feature of link protection will be
       modeled in the next revision.

   b.  Link bundle: The feature of link bundle will be modeled in the
       next revision.

3.  Model Structure

   The model tree structure of the Segment Routing (SR) topology module
   is as shown below:

   module: ietf-sr-topology
   augment /nw:networks/nw:network/nw:network-types/
   l3t:l3-unicast-topology:
      +--rw sr!
   augment /nw:networks/nw:network/l3t:l3-topology-attributes:
      +--rw sr



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         +--rw config
            +--rw srgb* [lower-bound upper-bound]
               +--rw lower-bound    uint32
               +--rw upper-bound    uint32
   augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes:
      +--rw sr
         +--rw config
         |  +--rw srgb* [lower-bound upper-bound]
         |  |  +--rw lower-bound    uint32
         |  |  +--rw upper-bound    uint32
         |  +--rw node-capabilities
         |     +--rw transport-planes* [transport-plane]
         |     |  +--rw transport-plane    identityref
         |     +--rw readable-label-stack-depth?   uint8
         +--ro state
            +--ro information-source?         enumeration
            +--ro information-source-state
            |  +--ro credibility-preference?   uint16
            +--ro node-capabilities
               +--ro transport-planes* [transport-plane]
               |  +--ro transport-plane    identityref
               +--ro readable-label-stack-depth?   uint8
   augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes/
   l3t:prefix:
      +--rw sr!
         +--rw value-type?          enumeration
         +--rw start-sid            uint32
         +--rw range?               uint32
         +--rw algorithm?           identityref
         +--rw last-hop-behavior?   enumeration {sid-last-hop-behavior}?
         +--rw is-local?            boolean
   augment /nw:networks/nw:network/nw:node/nt:termination-point/
   l3t:l3-termination-point-attributes:
   augment /nw:networks/nw:network/nt:link/l3t:l3-link-attributes:
      +--rw sr
         +--rw config
         |  +--rw sid?              uint32
         |  +--rw value-type?       enumeration
         |  +--rw is-local?         boolean
         |  +--ro is-part-of-set?   boolean
         |  +--ro is-on-lan?        boolean
         +--ro state
            +--ro information-source?         enumeration
            +--ro information-source-state
               +--ro credibility-preference?   uint16






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4.  YANG Module


   <CODE BEGINS> file "ietf-sr-topology@2016-10-28.yang"
   module ietf-sr-topology {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-sr-topology";
     prefix "srt";

     import ietf-network {
       prefix "nw";
     }
     import ietf-network-topology {
       prefix "nt";
     }
     import ietf-l3-unicast-topology {
       prefix "l3t";
     }
     import ietf-segment-routing-common {
       prefix "sr-cmn";
     }

     organization "TBD";
     contact "TBD";
     description "L3 TE Topology model";

     revision 2016-10-28 {
       description "Initial revision";
       reference "TBD";
     }

     grouping sr-topology-type {
       description
         "Identifies the SR topology type.";
       container sr {
         presence "Indiates SR Topology";
         description
           "Its presence identifies the SR topology type.";
       }
     }

     augment "/nw:networks/nw:network/nw:network-types/"
       + "l3t:l3-unicast-topology" {
       description
         "Defines the SR topology type.";
       uses sr-topology-type;
     }




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     augment "/nw:networks/nw:network/l3t:l3-topology-attributes" {
       when "../nw:network-types/l3t:l3-unicast-topology/sr" {
         description "Augment only for SR topology.";
       }
       description "Augment topology configuration";
       uses sr-topology-attributes;
     }

     augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes" {
       when "../../nw:network-types/l3t:l3-unicast-topology/sr" {
         description "Augment only for SR topology.";
       }
       description "Augment node configuration.";
       uses sr-node-attributes;
     }

     augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes"
       + "/l3t:prefix" {
       when "../../../nw:network-types/l3t:l3-unicast-topology/sr" {
         description "Augment only for SR topology.";
       }
       description "Augment node prefix.";
       uses sr-node-prefix-attributes;
     }

     augment "/nw:networks/nw:network/nw:node/nt:termination-point/"
       + "l3t:l3-termination-point-attributes" {
       when "../../../nw:network-types/l3t:l3-unicast-topology/"
         + "sr" {
         description "Augment only for SR topology.";
       }
       description "Augment termination point configuration";
       uses sr-tp-attributes;
     }

     augment "/nw:networks/nw:network/nt:link/l3t:l3-link-attributes" {
       when "../../nw:network-types/l3t:l3-unicast-topology/sr" {
         description "Augment only for SR topology.";
       }
       description "Augment link configuration.";
       uses sr-link-attributes;
     }

     grouping sr-topology-attributes {
       description "SR topology scope attributes.";
       container sr {
         description
           "Containing SR attributes.";



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         container config {
           description
             "Configuraiton attributes.";
           uses sr-cmn:srgb-cfg;
         }
       } // sr
     } // sr-topology-attributes

     grouping information-source-attributes {
       description
         "The attributes identifying source that has provided the
          related information, and the source credibility.";
       leaf information-source {
         type enumeration {
           enum "unknown" {
             description "The source is unknown.";
           }
           enum "locally-configured" {
             description "Configured entity.";
           }
           enum "ospfv2" {
             description "OSPFv2.";
           }
           enum "ospfv3" {
             description "OSPFv3.";
           }
           enum "isis" {
             description "ISIS.";
           }
           enum "system-processed" {
             description "System processed entity.";
           }
           enum "other" {
             description "Other source.";
           }
         }
         description
           "Indicates the source of the information.";
       }
       container information-source-state {
         description
           "The container contains state attributes related to
            the information source.";
         leaf credibility-preference {
           type uint16;
           description
             "The preference value to calculate the traffic
              engineering database credibility value used for



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              tie-break selection between different
              information-source values.
              Higher value is more preferable.";
         }
       }
     } // information-source-attributes

     grouping sr-node-attributes {
       description "SR node scope attributes.";
       container sr {
         description
           "Containing SR attributes.";
         container config {
           description
             "Configuraiton attributes.";
           uses sr-cmn:srgb-cfg;
           uses sr-cmn:node-capabilities;
         } // config
         container state {
           config false;
           description
             "Operational state data.";
           uses information-source-attributes;
           uses sr-cmn:node-capabilities;
         }
       } // sr
     } // sr-node-attributes

     grouping sr-node-prefix-attributes {
       description "Containing SR attributes for a prefix.";
       container sr {
         presence "Presence indicates SR is enabled.";
         description
           "Containing SR attributes for a prefix.";
         uses sr-cmn:prefix-sid-attributes;
         uses sr-cmn:last-hop-behavior;
         leaf is-local {
           type boolean;
           description
             "'true' if the SID is local.";
         }
       } // sr
     } // sr-node-prefix-attributes

     grouping sr-tp-attributes {
       description "SR termination point scope attributes";
     } // sr-tp-attributes




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     grouping sr-link-attributes {
       description "SR link scope attributes";
       container sr {
         description
           "Containing SR attributes.";
         container config {
           description
             "Configuraiton attributes.";
           leaf sid {
             type uint32;
             description
               "SID.";
           }
           uses sr-cmn:sid-value-type;
           leaf is-local {
             type boolean;
             description
               "'true' if the SID is local.";
           }
           leaf is-part-of-set {
             type boolean;
             config false;
             description
               "'true' if the SID is part of a set.";
           }
           leaf is-on-lan {
             type boolean;
             config false;
             description
               "'true' if on a lan.";
           }
         }
         container state {
           config false;
           description
             "Operational state data.";
           uses information-source-attributes;
         }
       } // sr
     } // sr-link-attributes
   }
   <CODE ENDS>









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5.  IANA Considerations

   RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
   actual RFC number (and remove this note).

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

   --------------------------------------------------------------------
   URI: urn:ietf:params:xml:ns:yang:ietf-sr-topology
   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 [RFC6020]:

   --------------------------------------------------------------------
   name:         ietf-sr-topology
   namespace:    urn:ietf:params:xml:ns:yang:ietf-sr-topology
   prefix:       srt
   reference:    RFC XXXX
   --------------------------------------------------------------------

6.  Security Considerations

   The configuration, state, action and notification data defined in
   this document are designed to be accessed via the NETCONF protocol
   [RFC6241].  The data-model by itself does not create any security
   implications.  The security considerations for the NETCONF protocol
   are applicable.  The NETCONF protocol used for sending the data
   supports authentication and encryption.

7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC6021]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6021, DOI 10.17487/RFC6021, October 2010,
              <http://www.rfc-editor.org/info/rfc6021>.






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   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <http://www.rfc-editor.org/info/rfc6241>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <http://www.rfc-editor.org/info/rfc7950>.

7.2.  Informative References

   [I-D.ietf-i2rs-yang-network-topo]
              Clemm, A., Medved, J., Varga, R., Tkacik, T., Bahadur, N.,
              Ananthakrishnan, H., and X. Liu, "A Data Model for Network
              Topologies", draft-ietf-i2rs-yang-network-topo-06 (work in
              progress), September 2016.

   [I-D.ietf-i2rs-yang-l3-topology]
              Clemm, A., Medved, J., Varga, R., Tkacik, T., Liu, X.,
              Bryskin, I., Guo, A., Ananthakrishnan, H., Bahadur, N.,
              and V. Beeram, "A YANG Data Model for Layer 3 Topologies",
              draft-ietf-i2rs-yang-l3-topology-04 (work in progress),
              September 2016.

   [I-D.ietf-teas-yang-te-topo]
              Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
              O. Dios, "YANG Data Model for TE Topologies", draft-ietf-
              teas-yang-te-topo-06 (work in progress), October 2016.

   [I-D.ietf-spring-sr-yang]
              Litkowski, S., Qu, Y., Sarkar, P., and J. Tantsura, "YANG
              Data Model for Segment Routing", draft-ietf-spring-sr-
              yang-05 (work in progress), October 2016.

Authors' Addresses

   Xufeng Liu
   Kuatro Technologies
   8281 Greensboro Drive, Suite 200
   McLean  VA 22102
   USA

   EMail: xliu@kuatrotech.com








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   Igor Bryskin
   Huawei Technologies

   EMail: Igor.Bryskin@huawei.com


   Vishnu Pavan Beeram
   Juniper Networks

   EMail: vbeeram@juniper.net


   Tarek Saad
   Cisco Systems Inc

   EMail: tsaad@cisco.com


   Himanshu Shah
   Ciena

   EMail: hshah@ciena.com


   Stephane Litkowski
   Orange Business Service

   EMail: stephane.litkowski@orange.com























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