Network Working Group                                            J. Dong
Internet-Draft                                                    X. Wei
Intended status: Standards Track                     Huawei Technologies
Expires: January 7, 2016                                    July 6, 2015


            A YANG Data Model for Layer-2 Network Topologies
              draft-ietf-i2rs-yang-l2-network-topology-01

Abstract

   This document defines a YANG data model for Layer 2 network
   topologies.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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 January 7, 2016.

Copyright Notice

   Copyright (c) 2015 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
   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



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   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
   2.  Layer-2 Topology Model  . . . . . . . . . . . . . . . . . . .   2
   3.  Layer-2 Topology Yang Module  . . . . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  18
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  18
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19

1.  Introduction

   [I-D.ietf-i2rs-yang-network-topo] defines the Yang [RFC6020]
   [RFC6021] data models of the abstract (generic) network and network
   topology.  Such models can be augmented with technology-specific
   details to build more specific topology models.

   This document defines the Yang data model for Layer 2 network
   topologies by augmenting the generic network and network topology
   data models with L2 specific topology attributes.

2.  Layer-2 Topology Model

   The Layer 2 network topology model is designed to be generic and
   applicable to Layer 2 networks built with different L2 technologies.

   The Layer 2 topology model applies the generic network and network
   topology models to Layer 2 network topologies, and augments the
   generic models with information specific in Layer 2 networks.  The
   relationship between the Layer 2 topology model and the generic
   network and network topology model is shown in the figure below:













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                           +---------------------+
                           |    ietf-network     |
                           +----------^----------+
                                      |
                                      |
                           +---------------------+
                           |ietf-network-topology|
                           +----------^----------+
                                      |
                                      |
                           +----------^----------+
                           |   ietf-l2-topology  |
                           +---------------------+
                   Figure 1. L2-topology model structure

   In order to represent a Layer 2 network topology, the generic network
   and topology models are augmented with Layer-2 specific information,
   such as the identifiers, descriptions, attributes and states of the
   Layer-2 networks, nodes, links and termination points.  Some of the
   information may be collected via Link Layer Discovery Protocl (LLDP)
   or other Layer-2 protocols, and some of them may be locally
   configured.

   The structure of "ietf-l2-topology" data model is depicted in the
   following diagram.  Brackets enclose list keys, "rw" means
   configuration data, "ro" means operational state data, "?" designates
   optional nodes, "*" designates nodes that can have multiple
   instances.

   module: ietf-l2-topology
   augment /nw:network/nw:network-types:
      +--rw l2-network!
   augment /nw:network:
      +--rw l2-network-attributes
         +--rw name?   string
         +--rw flag*   flag-type
   augment /nw:network/nw:node:
      +--rw l2-node-attributes
         +--rw name?                 string
         +--rw description?          string
         +--rw management-address*   inet:ip-address
         +--rw management-vid?       vlan {VLAN}?
         +--rw nick-name*            trill-nickname {TRILL}?
         +--rw flag*                 flag-type
   augment /nw:network/nt:link:
      +--rw l2-link-attributes
         +--rw name?    string
         +--rw flag*    flag-type



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         +--rw rate?    decimal64
         +--rw delay?   uint32
         +--rw srlg*    uint32
   augment /nw:network/nw:node/nt:termination-point:
      +--rw l2-termination-point-attributes
         +--rw description?          string
         +--rw maximum-frame-size?   uint32
         +--rw (l2-termination-point-type)?
         |  +--:(ethernet)
         |  |  +--rw mac-address?          yang:mac-address
         |  |  +--rw eth-encapsulation?    identityref
         |  |  +--rw port-vlan-id?         vlan {VLAN}?
         |  |  +--rw vlan-id-name* [vlan-id] {VLAN}?
         |  |     +--rw vlan-id      vlan
         |  |     +--rw vlan-name?   string
         |  +--:(legacy)
         |     +--rw encapsulation?        identityref
         +--ro tp-state?             enumeration
   notifications:
      +---n l2-node-event
      |  +--ro event-type?           l2-network-event-type
      |  +--ro network-ref?          leafref
      |  +--ro node-ref?             leafref
      |  +--ro l2-network!
      |  +--ro l2-node-attributes
      |     +--ro name?                 string
      |     +--ro description?          string
      |     +--ro management-address*   inet:ip-prefix
      |     +--ro management-vid?       vlan {VLAN}?
      |     +--ro nick-name*            trill-nickname {TRILL}?
      |     +--ro flag*                 flag-type
      +---n l2-link-event
      |  +--ro event-type?           l2-network-event-type
      |  +--ro network-ref?          leafref
      |  +--ro link-ref?             leafref
      |  +--ro l2-network!
      |  +--ro l2-link-attributes
      |     +--ro name?    string
      |     +--ro flag*    flag-type
      |     +--ro rate?    decimal64
      |     +--ro delay?   uint32
      |     +--ro srlg*    uint32
      +---n l2-termination-point-event
         +--ro event-type?                        l2-network-event-type
         +--ro network-ref?                       leafref
         +--ro node-ref?                          leafref
         +--ro tp-ref?                            leafref
         +--ro l2-network!



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         +--ro l2-termination-point-attributes
            +--ro description?          string
            +--ro maximum-frame-size?   uint32
            +--ro (termination-point-type)?
            |  +--:(ethernet)
            |  |  +--ro mac-address?          yang:mac-address
            |  |  +--ro eth-encapsulation?    identityref
            |  |  +--ro port-vlan-id?         vlan {VLAN}?
            |  |  +--ro vlan-id-name* [vlan-id] {VLAN}?
            |  |     +--ro vlan-id      vlan
            |  |     +--ro vlan-name?   string
            |  +--:(legacy)
            |     +--ro encapsulation?        identityref
            +--ro tp-state?             enumeration

   The L2-topology module augments the generic ietf-network and ietf-
   network-topology modules as follows:

   o  A new network type "l2-network-type" is introduced.  This is
      represented by a container object, and is inserted under the
      "network-types" container of the generic ietf-network module in
      [I-D.ietf-i2rs-yang-network-topo].

   o  Additional network attributes are introduced in a grouping "l2-
      network-attributes", which augments the "network" list of the
      ietf-network module.  The attributes include Layer-2 network name
      and a set of flags.  Each type of flag is represented by a
      separate identity.

   o  Additional data objects for Layer-2 nodes are introduced by
      augmenting the "node" list of the generic ietf-network module.
      New objects include Layer-2 node identifier, description,
      management address, and a set of flags.

   o  Additional data objects for Layer-2 termination points are
      introduced by augmenting the "termination-point" list of the ietf-
      network-topology module defined in
      [I-D.ietf-i2rs-yang-network-topo].  New objects include Layer-2
      termination point descriptions, Layer-2 termination point type
      specific attributes and Layer-2 termination point states.

   o  Links in the ietf-network-topology module are augmented as well
      with a set of Layer-2 parameters, allowing to associate a link
      with a name, a set of Layer-2 link attributes and flags.

   o  The optional L2 technology specific attributes are introduced in
      this module as Layer-2 features.




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3.  Layer-2 Topology Yang Module

   <CODE BEGINS>
   file "ietf-l2-topology@2015-06-23.yang"
   module ietf-l2-topology {
       yang-version 1;
       namespace "urn:ietf:params:xml:ns:yang:ietf-l2-topology";
       prefix "l2t";

       import ietf-network {
         prefix "nw";
       }

       import ietf-network-topology {
         prefix "nt";
       }

       import ietf-inet-types {
         prefix "inet";
       }

       import ietf-yang-types {
         prefix "yang";
       }

       organization "TBD";
       contact "I-D Editor: jie.dong@huawei.com";

       description
         "This module defines a basic model for
          the layer-2 topology of a network";

       revision "2015-06-23" {
         description "Initial revision";
         reference "draft-ietf-i2rs-l2-network-topology-01";
       }

      /*
       * Typedefs
       */

       typedef vlan {
         type uint16 {
           range "0..4095";
         }
         description "VLAN ID";
       }




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       typedef trill-nickname {
         type uint16;
         description "TRILL Nickname";
       }

       typedef flag-type {
         type identityref {
           base "flag-identity";
         }
         description "Base type for flags";
       }

       typedef l2-network-event-type {
         type enumeration {
           enum "add" {
             value 0;
             description "An L2 node or link or termination-point
             has been added";
           }
           enum "remove" {
             value 1;
             description "An L2 node or link or termination-point
             has been removed";
           }
           enum "update" {
             value 2;
             description "An L2 node or link or termination-point
             has been updated";
           }
         }
         description "l2 network event type for notifications";
       } // l2-topology-event-type



       /*
       * Features
       */

       feature VLAN {
         description
           "Indicates that the system supports the
            vlan functions";
       }

       feature QinQ {
         description
           "Indicates that the system supports the



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            qinq functions";
       }

       feature PBB {
         description
          "Indicates that the device supports the
           provider-backbone-bridging functions";
       }

       feature VPLS {
         description
           "Indicates that the device supports the
            VPLS functions";
         reference "RFC 4761, RFC 4762";
       }

       feature TRILL {
         description
           "Indicates that the device supports the
            TRILL functions";
         reference "RFC 6325";
       }

       feature VXLAN {
         description
           "Indicates that the device supports the
            VXLAN functions";
         reference "RFC 7348";
       }

      /*
       * Identities
       */


       identity flag-identity {
         description "Base type for flags";
       }

       identity encapsulation-type {
         description
           "Base identity from which specific encapsulation
            types are derived.";
       }

       identity eth-encapsulation-type {
         base encapsulation-type;
         description



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           "Base identity from which specific ethernet
            encapsulation types are derived.";

       }

       identity ethernet {
         base eth-encapsulation-type;
         description
           "native ethernet encapsulation";
       }

       identity vlan {
         base eth-encapsulation-type;
         description
           "vlan encapsulation";
       }

       identity qinq {
         base eth-encapsulation-type;
         description
           "qinq encapsulation";
       }

       identity pbb {
         base eth-encapsulation-type;
         description
           "pbb encapsulation";
       }

       identity trill {
         base eth-encapsulation-type;
         description
           "trill encapsulation";
       }

       identity vpls {
         base eth-encapsulation-type;
         description
           "vpls encapsulation";
       }

       identity vxlan {
         base eth-encapsulation-type;
         description
           "vxlan encapsulation";
       }

       identity frame-relay {



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         base encapsulation-type;
         description
           "Frame Relay encapsulation";
       }

       identity ppp {
         base encapsulation-type;
         description
           "PPP encapsulation";
       }

       identity hdlc {
         base encapsulation-type;
         description
           "HDLC encapsulation";
       }

       identity atm {
         base encapsulation-type;
         description
           "Base identity from which specific ATM
            encapsulation types are derived.";

       }

       identity pwe3 {
         base encapsulation-type;
         description
           "Base identity from which specific pw
            encapsulation types are derived.";
       }


      /*
       * Groupings
       */


       grouping l2-network-type {
         description "Identify the topology type to be L2.";
         container l2-network {
           presence "indicates L2 Network";
           description
           "The presence of the container node indicates
            L2 Topology";
         }
       }




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       grouping l2-network-attributes {
         description "L2 Topology scope attributes";
         container l2-network-attributes {
           description "Containing L2 network attributes";
           leaf name {
             type string;
             description "Name of the L2 network";
           }

           leaf-list flag {
             type flag-type;
             description "L2 network flags";
           }
         }
       }

       grouping l2-node-attributes {
         description "L2 node attributes";
         container l2-node-attributes {
           description "Containing L2 node attributes";
           leaf name {
             type string;
             description "Node name";
           }
           leaf description {
             type string;
             description "Node description";
           }
           leaf-list management-address {
             type inet:ip-address;
             description "System management address";
           }
           leaf management-vid {
             if-feature VLAN;
             type vlan;
             description "System management VID";
           }
           leaf-list nick-name {
             if-feature TRILL;
             type trill-nickname;
             description "Nickname of the RBridge";
           }
           leaf-list flag {
             type flag-type;
             description "Node operational flags";
           }
         }
       }  // grouping l2-node-attributes



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       grouping l2-link-attributes {
         description "L2 link attributes";
         container l2-link-attributes {
           description "Containing L2 link attributes";
           leaf name {
             type string;
             description "Link name";
           }
           leaf-list flag {
             type flag-type;
             description "Link flags";
           }
           leaf rate {
             type decimal64 {
               fraction-digits 2;
             }
             description "Link rate";

           }
           leaf delay {
             type uint32;
             description "Link delay in microseconds";
           }
           leaf-list srlg {
             type uint32;
             description
               "List of Shared Risk Link Groups
                this link belongs to.";
           }
         }
       } // grouping l2-link-attributes

       grouping l2-termination-point-attributes {
         description "L2 termination point attributes";
         container l2-termination-point-attributes {
           description "Containing L2 TP attributes";
           leaf description {
             type string;
             description "Port description";
           }

           leaf maximum-frame-size {
             type uint32;
             description "Maximum frame size";
           }

           choice l2-termination-point-type {
             description



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               "Indicates termination-point type
                specific attributes";
             case ethernet {
               leaf mac-address {
                 type yang:mac-address;
                 description "Interface MAC address";
               }

               leaf eth-encapsulation {
                 type identityref {
                   base eth-encapsulation-type;
                 }
                 description
                   "Encapsulation type of this
                    ternimation point.";
               }

               leaf port-vlan-id {
                 if-feature VLAN;
                 type vlan;
                 description "Port VLAN ID";
               }

               list vlan-id-name {
                 if-feature VLAN;
                 key "vlan-id";
                 description "Interface configured VLANs";
                 leaf vlan-id {
                   type vlan;
                   description "VLAN ID";
                 }
                 leaf vlan-name {
                   type string;
                   description "VLAN Name";
                 }
               }
             } //case ethernet

             case legacy {
               leaf encapsulation {
                 type identityref {
                   base encapsulation-type;
                 }
                 description
                   "Encapsulation type of this termination point.";
               }
             } //case legacy




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           } //choice termination-point-type

           leaf tp-state {
             type enumeration {
               enum in-use {
                 value 0;
                 description
                   "the termination point is in forwarding state";
               }
               enum blocking {
                 value 1;
                 description
                   "the termination point is in blocking state";
               }
               enum down {
                 value 2;
                 description
                   "the termination point is in down state";
               }
               enum others {
                 value 3;
                 description
                   "the termination point is in other state";
               }
             }
             config false;
             description "State of the termination point";
           }
         }
       } // grouping l2-termination-point-attributes

   /*** grouping of network/node/link/tp leaf-refs ***/

     grouping network-ref {
       description
         "Grouping for an absolute reference to a network topology
         instance.";
       leaf network-ref {
         type leafref {
           path "/nw:network/nw:network-id";
         }
         description
           "An absolute reference to a network topology instance.";
       }
     }

     grouping link-ref {
       description



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         "Grouping for an absolute reference to a link instance.";
         uses network-ref;
         leaf link-ref {
           type leafref {
             path "/nw:network"
               +"[nw:network-id = current()/../network-ref]"
               +"/nt:link/nt:link-id";
           }
         description
           "An absolute reference to a link instance.";
       }
     }

     grouping node-ref {
       description
         "Grouping for an absolute reference to a node instance.";
       uses network-ref;
       leaf node-ref {
         type leafref {
           path "/nw:network"
             +"[nw:network-id = current()/../network-ref]"
             +"/nw:node/nw:node-id";
         }
         description
           "An absolute reference to a node instance.";
       }
     }

     grouping tp-ref {
       description
         "Grouping for an absolute reference to a termination point.";
       uses node-ref;
       leaf tp-ref {
         type leafref {
           path "/nw:network"
             +"[nw:network-id = current()/../network-ref]"
             +"/nw:node[nw:node-id = current()/../node-ref]"
             +"/nt:termination-point/nt:tp-id";
         }
         description
           "Grouping for an absolute reference to a TP.";
       }
     }


      /*
       * Data nodes
       */



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       augment "/nw:network/nw:network-types" {
         description
           "Introduce new network type for L2 topology";
         uses l2-network-type;
       }

       augment "/nw:network" {
         when "nw:network-types/l2-network" {
           description
             "Augmentation parameters apply only for networks
              with L2 topology";
         }
         description
           "Configuration parameters for the L2 network
            as a whole";
         uses l2-network-attributes;
       }

       augment "/nw:network/nw:node" {
         when "../nw:network-types/l2-network" {
           description
             "Augmentation parameters apply only for networks
              with L2 topology";
         }
         description
           "Configuration parameters for L2 at the node
            level";
         uses l2-node-attributes;
       }

       augment "/nw:network/nt:link" {
         when "/nw:network/nw:network-types/l2-network" {
           description
             "Augmentation parameters apply only for networks
              with L2 topology";
         }
         description "Augment L2 topology link information";
         uses l2-link-attributes;
       }

       augment "/nw:network/nw:node/nt:termination-point" {
         when "/nw:network/nw:network-types/l2-network" {
           description
             "Augmentation parameters apply only for networks
              with L2 topology";
         }
         description
           "Augment L2 topology termination point configuration";



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         uses l2-termination-point-attributes;
       }

      /*
       * Notifications
       */

       notification l2-node-event {
         description "Notification event for L2 node";
         leaf event-type {
           type l2-network-event-type;
           description "Event type";
         }
         uses node-ref;
         uses l2-network-type;
         uses l2-node-attributes;
       }

       notification l2-link-event {
         description "Notification event for L2 link";
         leaf event-type {
           type l2-network-event-type;
           description "Event type";
         }
         uses link-ref;
         uses l2-network-type;
         uses l2-link-attributes;
       }

       notification l2-termination-point-event {
         description "Notification event for L2 termination point";
         leaf event-type {
           type l2-network-event-type;
           description "Event type";
         }
         uses tp-ref;
         uses l2-network-type;
         uses l2-termination-point-attributes;
       }

   }  // module l2-topology
   <CODE ENDS>

4.  IANA Considerations

   TBD





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5.  Security Considerations

   The transport protocol used for sending the topology data MUST
   support authentication and SHOULD support encryption.  The data-model
   by itself does not create any security implications.

6.  Acknowledgements

   The authors would like to acknowledge the comments and suggestions
   received from Susan Hares, Alia Atlas, Juergen Schoenwaelder, Mach
   Chen, Alexander Clemm and Sriganesh Kini.

7.  References

7.1.  Normative References

   [I-D.ietf-i2rs-yang-network-topo]
              Clemm, A., Medved, J., Varga, R., Tkacik, T., Bahadur, N.,
              and H. Ananthakrishnan, "A Data Model for Network
              Topologies", draft-ietf-i2rs-yang-network-topo-01 (work in
              progress), June 2015.

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

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

   [RFC6021]  Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
              October 2010.

7.2.  Informative References

   [I-D.amante-i2rs-topology-use-cases]
              Medved, J., Previdi, S., Lopez, V., and S. Amante,
              "Topology API Use Cases", draft-amante-i2rs-topology-use-
              cases-01 (work in progress), October 2013.

   [I-D.medved-i2rs-topology-requirements]
              Medved, J., Previdi, S., Gredler, H., Nadeau, T., and S.
              Amante, "Topology API Requirements", draft-medved-i2rs-
              topology-requirements-00 (work in progress), February
              2013.







Dong & Wei               Expires January 7, 2016               [Page 18]


Internet-Draft     Layer-2 Network Topology Data Model         July 2015


Authors' Addresses

   Jie Dong
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: jie.dong@huawei.com


   Xiugang Wei
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: weixiugang@huawei.com

































Dong & Wei               Expires January 7, 2016               [Page 19]