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Versions: (draft-zhuang-i2rs-yang-dc-fabric-network-topology) 00 01 02 03 04 05 06 07 08 09

I2RS Working Group                                             Y. Zhuang
Internet-Draft                                                    D. Shi
Intended status: Standards Track                                  Huawei
Expires: October 20, 2018                                          R. Gu
                                                            China Mobile
                                                      H. Ananthakrishnan
                                                           Packet Design
                                                          April 18, 2018


     A YANG Data Model for Fabric Topology in Data Center Networks
           draft-ietf-i2rs-yang-dc-fabric-network-topology-09

Abstract

   This document defines a YANG data model for fabric topology in Data
   Center Networks.

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 https://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 October 20, 2018.

Copyright Notice

   Copyright (c) 2018 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
   (https://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




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Definitions and Acronyms  . . . . . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Model Overview  . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Topology Model structure  . . . . . . . . . . . . . . . .   4
     3.2.  Fabric Topology Model . . . . . . . . . . . . . . . . . .   4
       3.2.1.  Fabric Topology . . . . . . . . . . . . . . . . . . .   4
       3.2.2.  Fabric node extension . . . . . . . . . . . . . . . .   5
       3.2.3.  Fabric termination-point extension  . . . . . . . . .   6
   4.  Fabric YANG Module  . . . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  21
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  22
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  22
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  23
   Appendix A.  Non NMDA -state modules  . . . . . . . . . . . . . .  24
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  30

1.  Introduction

   Normally, a data center (DC) network is composed of single or
   multiple fabrics which are also known as PODs (Points Of Delivery).
   These fabrics may be heterogeneous due to implementation of different
   technologies when a DC network is upgraded or new techniques and
   features are rolled out.  For example, Fabric A may use VXLAN while
   Fabric B may use VLAN within a DC network.  Likewise, an existing
   fabric may use VXLAN while a new fabric, for example a fabric
   introduced for DC upgrade and expansion, may implement a technique
   discussed in NVO3 WG, such as Geneve [I-D. draft-ietf-nvo3-geneve].
   The configuration and management of such DC networks with
   heterogeneous fabrics will result in considerable complexity,
   requiring a fair amount of sophistication.

   Luckily, for a DC network, a fabric can be considered as an atomic
   structure for management purposes.  From this point of view, the
   management of the DC network can be decomposed into a set of tasks to
   manage each fabric separately, as well as the fabric
   interconnections.  This way, the overall management task becomes very
   flexible and makes it easy to expand and adopt to DC networks that
   evolve over time.





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   As a basis for DC fabric management, this document defines a YANG
   data model [RFC6020][RFC7950] for fabric-based data center topology.
   To do so, it augments the generic network and network topology data
   models defined in [RFC8345] with information that is specific to Data
   Center fabric networks.

   The model defines the generic configuration and operational state for
   a fabric-based network topology, which can subsequently be extended
   by vendors with vendor-specific information as needed.  The model can
   be used by a network controller to represent its view of the fabric
   topology that it controls and expose this view to network
   administrators or applications for DC network management.

   Within the context of topology architecture defined in [RFC8345],
   this model can also be treated as an application of the I2RS network
   topology model [RFC8345] in the scenario of Data center network
   management.  It can also act as a service topology when mapping
   network elements at the fabric layer to elements of other topologies,
   such as L3 topologies as defined in [RFC8346].

   By using the fabric topology model defined in this document, people
   can treat a fabric as a holistic entity and focus on characteristics
   of a fabric (such as encapsulation type, gateway type, etc.) as well
   as its connections to other fabrics while putting the underlay
   topology aside.  As such, clients can consume the topology
   information at the fabric level with no need to be aware of the
   entire set of links and nodes in the corresponding underlay networks.
   A fabric topology can be configured by a network administrator using
   the controller by adding physical devices and links into a fabric.
   Alternatively, fabric topology can be learned from the underlay
   network infrastructure.

2.  Definitions and Acronyms

   The key words "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] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.1.  Terminology

   POD: a module of network, compute, storage, and application
   components that work together to deliver networking services.  It
   represents a repeatable design pattern.  Its components maximize the
   modularity, scalability, and manageability of data centers.

   Fabric: composed of several PODs to form a data center network.



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3.  Model Overview

   This section provides an overview of the data center fabric topology
   model and its relationship with other topology models.

3.1.  Topology Model structure

   The relationship of the DC fabric topology model and other topology
   models is shown in the following figure.

             +------------------------+
             |      network model     |
             +------------------------+
                          |
                          |
             +------------V-----------+
             | network topology model |
             +------------------------+
                          |
        +-----------+-----+------+-------------+
        |           |            |             |
    +---V----+  +---V----+   +---V----+   +----V---+
    |   L1   |  |   L2   |   |   L3   |   | Fabric |
    |topology|  |topology|   |topology|   |topology|
    |  model |  |  model |   |  model |   |  model |
    +--------+  +--------+   +--------+   +--------+
       Figure 1: The network data model structure

   From the perspective of resource management and service provisioning
   for a data center network, the fabric topology model augments the
   basic network topology model with definitions and features specific
   to a DC fabric, to provide common configuration and operations for
   heterogeneous fabrics.

3.2.  Fabric Topology Model

   The fabric topology model module is designed to be generic and can be
   applied to data center fabrics built with different technologies,
   such as VLAN, VXLAN etc.  The main purpose of this module is to
   configure and manage fabrics and their connections.  It provides a
   fabric-based topology view for data center applications.

3.2.1.  Fabric Topology

   In the fabric topology module, a fabric is modeled as a node of a
   network, as such the fabric-based data center network consists of a
   set of fabric nodes and their connections.  The following depicts a




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   snippet of the definitions to show the main structure of the model.
   The notation syntax follows [RFC8340].

       module: ietf-dc-fabric-topology
       augment /nw:networks/nw:network/nw:network-types:
          +--rw fabric-network!
       augment /nw:networks/nw:network/nw:node:
          +--rw fabric-attributes
             +--rw fabric-id?   fabric-id
             +--rw name?        string
             +--rw type?        fabrictype:underlay-network-type
             +--rw description?    string
             +--rw options
             +--...
       augment /nw:networks/nw:network/nw:node/nt:termination-point:
          +--ro fport-attributes
             +--ro name?          string
             +--ro role?          fabric-port-role
             +--ro type?          fabric-port-type


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

   o  A new topology type "ietf-dc-fabric-topology" is introduced and
      added under the "network-types" container of the ietf-network
      module.

   o  Fabric is defined as a node under the network/node container.  A
      new container "fabric-attributes" is defined to carry attributes
      for a fabric such as gateway mode, fabric types, involved device
      nodes, and links.

   o  Termination points (in network topology module) are augmented with
      fabric port attributes defined in a container.  The "termination-
      point" here is used to represent a fabric "port" that provides
      connections to other nodes, such as an internal device, another
      fabric externally, or end hosts.

   Details of the fabric node and the fabric termination point extension
   will be explained in the following sections.

3.2.2.  Fabric node extension

   As an atomic network, a fabric itself is composed of a set of network
   elements i.e. devices, and related links.  The configuration of a
   fabric is contained under the "fabric-attributes" container depicted
   as follows.  The notation syntax follows [RFC8340].



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       +--rw fabric-attributes
          +--rw fabric-id?      fabrictypes:fabric-id
          +--rw name?           string
          +--rw type?           fabrictype:underlay-network-type
          +--rw vni-capacity
          |  +--rw min?   int32
          |  +--rw max?   int32
          +--rw description?    string
          +--rw options
          |  +--rw gateway-mode?           enumeration
          |  +--rw traffic-behavior?       enumeration
          |  +--rw capability-supported* fabrictype:service-capabilities
          +--rw device-nodes* [device-ref]
          |  +--rw device-ref    fabrictype:node-ref
          |  +--rw role*?         fabrictype:device-role
          +--rw device-links* [link-ref]
          |  +--rw link-ref    fabrictype:link-ref
          +--rw device-ports* [port-ref]
             +--rw port-ref     fabrictype:tp-ref
             +--rw port-type?   fabrictypes:port-type
             +--rw bandwidth?   fabrictypes:bandwidth


   In the module, additional data objects for fabric nodes are
   introduced by augmenting the "node" list of the network module.  New
   objects include fabric name, type of the fabric, descriptions of the
   fabric as well as a set of options defined in an "options" container.
   The "options" container includes the gateway-mode type (centralized
   or distributed) and traffic-behavior (whether an Access Control Lists
   (ACLs) is needed for the traffic).  Also, it includes a list of
   device-nodes and related links as supporting-nodes to form a fabric
   network.  These device nodes and links are represented as leaf-refs
   of existing nodes and links in the underlay topology.  For the
   device-node, the "role" object is defined to represent the role of a
   device within the fabric, such as "SPINE" or "LEAF", which should
   work together with the gateway-mode.

3.2.3.  Fabric termination-point extension

   Since a fabric can be considered as a node, "termination-points" can
   represent fabric "ports" that connect to other fabrics, end hosts, as
   well as devices inside the fabric.

   As such, the set of "termination-points" of a fabric indicate all
   connections of the fabric, including its internal connections,
   interconnections with other fabrics, and connections to end hosts.





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   The structure of fabric ports is as follows.  The notation syntax
   follows [RFC8340].

   The structure of fabric ports is as follows:

       augment /nw:networks/nw:network/nw:node/nt:termination-point:
           +--ro fport-attributes
              +--ro name?          string
              +--ro role?          fabric-port-role
              +--ro type?          fabric-port-type
              +--ro device-port?   tp-ref
              +--ro (tunnel-option)?


   It augments the termination points (in network topology module) with
   fabric port attributes defined in a container.

   New nodes are defined for fabric ports including fabric name, role of
   the port within the fabric (internal port, external port to outside
   network, access port to end hosts), port type (l2 interface, l3
   interface, etc).  By defining the device-port as a tp-ref, a fabric
   port can be mapped to a device node in the underlay network.

   Also, a new container for tunnel-options is introduced to present the
   tunnel configuration on a port.

   The termination point information is learned from the underlay
   networks, not configured by the fabric topology layer.

4.  Fabric YANG Module

   This module imports typedefs from [RFC8345], and it references
   [RFC7348] and [RFC8344].

   <CODE BEGINS> file "ietf-dc-fabric-types@2018-04-16.yang"
        module ietf-dc-fabric-types {

       yang-version 1.1;
       namespace "urn:ietf:params:xml:ns:yang:ietf-dc-fabric-types";
       prefix fabrictypes;

       import ietf-network {
           prefix nw;

           reference
           "RFC 8345:A Data Model for Network Topologies";
       }




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       organization
       "IETF I2RS (Interface to the Routing System) Working Group";

       contact
       "WG Web:    <http://tools.ietf.org/wg/i2rs/ >
        WG List:   <mailto:i2rs@ietf.org>

        Editor:    Yan Zhuang
                   <mailto:zhuangyan.zhuang@huawei.com>

        Editor:    Danian Shi
                   <mailto:shidanian@huawei.com>";

       description
           "This module contains a collection of YANG definitions for
           Fabric.

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

           Redistribution and use in source and binary forms, with or
           without modification, is permitted pursuant to, and subject
           to the license terms contained in, the Simplified BSD License
           set forth in Section 4.c of the IETF Trust's Legal Provisions
           Relating to IETF Documents
           (https://trustee.ietf.org/license-info).

           This version of this YANG module is part of
           draft-ietf-i2rs-yang-dc-fabric-network-topology;
           see the RFC itself for full legal notices.

           NOTE TO RFC EDITOR: Please replace above reference to
           draft-ietf-i2rs-yang-dc-fabric-network-topology-09 with RFC
           number when published (i.e. RFC xxxx).";

       revision "2018-04-16"{
           description
               "Initial revision.
                NOTE TO RFC EDITOR:
                Please replace the following reference to
                draft-ietf-i2rs-yang-dc-fabric-network-topology-09
                with RFC number when published (i.e. RFC xxxx).";
           reference
               "draft-ietf-i2rs-yang-dc-fabric-network-topology-09";
       }

       identity fabric-type {
           description



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               "Base type for fabric networks";
       }

       identity vxlan-fabric {
           base fabric-type;
           description
               "Vxlan fabric";
       }

       identity vlan-fabric {
           base fabric-type;
           description
               "Vlan fabric";
       }

       identity trill-fabric {
           base fabric-type;
           description "Trill fabric";
       }
       identity port-type {
           description
               "Base type for fabric port";
       }
       identity eth {
           base port-type;
           description "ETH";
       }
       identity serial {
           base port-type;
           description "Serial";
       }

       identity bandwidth {
           description "Base for bandwidth";
       }
       identity bw-1M {
           base bandwidth;
           description "1M";
       }
       identity bw-10M {
           base bandwidth;
           description "10M";
       }
       identity bw-100M {
           base bandwidth;
           description "100M";
       }
       identity bw-1G {



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           base bandwidth;
           description "1G";
       }
       identity bw-10G {
           base bandwidth;
           description "10G";
       }
       identity bw-40G {
           base bandwidth;
           description "40G";
       }
       identity bw-100G{
           base bandwidth;
           description "100G";
       }

       identity device-role {
           description "Base for the device role in a fabric.";
       }
       identity spine {
           base device-role;
           description "This is a spine node in a fabric.";
       }
       identity leaf {
           base device-role;
           description "This is a leaf node in a fabric. ";
       }
       identity border {
           base device-role;
           description "This is a border node to connect to other
           fabric/network.";
       }
       identity fabric-port-role {
           description "Base for the port's role in a fabric.";
       }
       identity internal {
           base fabric-port-role;
           description "The port is used for devices to access each
           other within a fabric.";
       }
       identity external {
           base fabric-port-role;
           description "The port is used for a fabric to connect to
           outside network.";
       }
       identity access {
           base fabric-port-role;
           description "The port is used for an endpoint to connect



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            to a fabric.";
       }

       identity service-capability {
           description "Base for the service of the fabric ";
       }
       identity ip-mapping {
           base service-capability;
           description "NAT.";
       }
       identity acl-redirect {
           base service-capability;
           description "Acl redirect, which can provide SFC function.";
       }
       identity dynamic-route-exchange {
           base service-capability;
           description "Dynamic route exchange.";
       }


        /*
        * Typedefs
        */
       typedef fabric-id {
           type nw:node-id;
           description
               "An identifier for a fabric in a topology.
               This identifier can be generated when composing a fabric.
               The composition of a fabric can be achived by defining a
               RPC, which is left for vendor specific implementation
               and not provided in this model.";
       }

       typedef service-capabilities {
           type identityref {
                base service-capability;
           }
           description
               "Service capability of the fabric";
       }

       typedef port-type {
           type identityref {
                base port-type;
           }
           description "Port type: ethernet or serial or others.";
       }
       typedef bandwidth {



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           type identityref {
                base bandwidth;
           }
           description "Bandwidth of the port.";
       }
       typedef node-ref {
           type instance-identifier;
           description "A reference to a node in topology";
       }

       typedef tp-ref {
           type instance-identifier;
           description "A reference to a termination point in topology";
       }

       typedef link-ref {
           type instance-identifier;
           description "A reference to a link in topology";
       }

       typedef underlay-network-type {
           type identityref {
                base fabric-type;
           }
           description "The type of physical network that implements
           this fabric.Examples are vlan, and trill.";
       }
       typedef device-role {
            type identityref {
                base device-role;
           }
           description "Role of the device node.";
       }
       typedef fabric-port-role {
           type identityref {
                base fabric-port-role;
           }
           description "Role of the port in a fabric.";
       }

       typedef fabric-port-type {
           type enumeration {
               enum layer2interface {
                   description "L2 interface";
               }
               enum layer3interface {
                   description "L3 interface";
               }



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               enum layer2Tunnel {
                   description "L2 tunnel";
               }
               enum layer3Tunnel {
                   description "L3 tunnel";
               }
           }
           description
               "Fabric port type";
       }

       grouping fabric-port {
           description
               "Attributes of a fabric port.";
           leaf name {
               type string;
               description "Name of the port.";
           }
           leaf role {
               type fabric-port-role;
               description "Role of the port in a fabric.";
           }
           leaf type {
               type fabric-port-type;
               description "Type of the port";
           }
           leaf device-port {
               type tp-ref;
               description "The device port it mapped to.";
           }
           choice tunnel-option {
               description "Tunnel options to connect two fabrics.
               It could be L2 Tunnel or L3 Tunnel.";
           }
       }
   }
   <CODE ENDS>

   <CODE BEGINS> file "ietf-dc-fabric-topology@2018-04-16.yang"
       module ietf-dc-fabric-topology {

       yang-version 1.1;
       namespace "urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology";
       prefix fabric;

       import ietf-network {
           prefix nw;




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           reference
           "RFC 8345:A Data Model for Network Topologies";
       }

       import ietf-network-topology {
           prefix nt;

           reference
            "RFC 8345:A Data Model for Network Topologies";
       }

       import ietf-dc-fabric-types {
           prefix fabrictypes;

           reference
           "draft-ietf-i2rs-yang-dc-fabric-network-topology-09
            NOTE TO RFC EDITOR:
            (1) Please replace above reference to
            draft-ietf-i2rs-yang-dc-fabric-network-topology-09
            with RFC number when publised (i.e. RFC xxxx).
            (2) Please replace the data in the revision statement
             with the data of publication when published.";
       }

       organization
       "IETF I2RS (Interface to the Routing System) Working Group";

       contact
       "WG Web:    <http://tools.ietf.org/wg/i2rs/ >
        WG List:   <mailto:i2rs@ietf.org>

        Editor:    Yan Zhuang
                   <mailto:zhuangyan.zhuang@huawei.com>

        Editor:    Danian Shi
                   <mailto:shidanian@huawei.com>";


       description
       "This module contains a collection of YANG definitions for
       Fabric.

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

       Redistribution and use in source and binary forms, with or
       without modification, is permitted pursuant to, and subject
       to the license terms contained in, the Simplified BSD License



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       set forth in Section 4.c of the IETF Trust's Legal Provisions
       Relating to IETF Documents
       (https://trustee.ietf.org/license-info).

       This version of this YANG module is part of
       draft-ietf-i2rs-yang-dc-fabric-network-topology;
       see the RFC itself for full legal notices.

       NOTE TO RFC EDITOR: Please replace above reference to
       draft-ietf-i2rs-yang-dc-fabric-network-topology-09 with RFC
       number when published (i.e. RFC xxxx).";

       revision "2018-04-16"{
           description
                "Initial revision.
                 NOTE TO RFC EDITOR: Please replace the following
                 reference to draft-ietf-i2rs-yang-dc-fabric-network
                 -topology-09 with RFC number when published
                 (i.e. RFC xxxx).";
           reference
               "draft-ietf-i2rs-yang-dc-fabric-network-topology-09";
       }

       /*identity fabric-context {
           description
               "Identity of fabric context";
       }*/

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

       grouping fabric-options {
           description "Options for a fabric";

           leaf gateway-mode {
               type enumeration {
                   enum centralized {
                       description "The Fabric uses centerilized
                       gateway,in which gateway is deployed on SPINE
                       node.";



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                   }
                   enum distributed {
                       description "The Fabric uses distributed
                       gateway, in which gateway is deployed on LEAF
                       node.";
                   }
               }
               default "distributed";
               description "Gateway mode of the fabric";
           }

           leaf traffic-behavior {
               type enumeration {
                   enum normal {
                       description "Normal means no policy is needed
                       for all traffic";
                   }
                   enum policy-driven {
                       description "Policy driven means policy is
                       needed for the traffic otherwise the traffic
                       will be discard.";
                   }
               }
               default "normal";
               description "Traffic behavior of the fabric";
           }

           leaf-list capability-supported {
               type fabrictypes:service-capabilities;
               description
                   "It provides a list of supported services of the
                   fabric. The service-capabilities is defined as
                   identity-ref. Developers can define more services
                   by defining new identies.";
           }
       }

       grouping device-attributes {
           description "device attributes";
           leaf device-ref {
               type fabrictypes:node-ref;
               description
                   "The device that the fabric includes which refers
                   to a node in another topolopogy.";
           }
           leaf-list role {
               type fabrictypes:device-role;
               default fabrictypes:leaf;



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               description
                   "It is a list of devce-role to represent the roles
                   that a device plays within a PoD, such as SPINE,
                   LEAF, Border, or Border-Leaf.
                   The device-role is defined as identity-ref. If more
                   than 2 stage is used for a PoD, developers can
                   define new identities for the device-role.";
           }
       }

       grouping link-attributes {
           description "Link attributes";
           leaf link-ref {
               type fabrictypes:link-ref;
               description
                   "The link that the fabric includes which refers to
                   a link in another topology.";
           }
       }

       grouping port-attributes {
           description "Port attributes";
           leaf port-ref {
               type fabrictypes:tp-ref;
               description
                   "The port that the fabric includes which refers to
                   a termination-point in another topology.";
           }
           leaf port-type {
               type fabrictypes:port-type;
               description
                   "Port type is defined as identiy-ref. If current
                   types includes ethernet or serial. If more types
                   are needed, developers can define new identities.";
           }
           leaf bandwidth {
               type fabrictypes:bandwidth;
               description
                 "Bandwidth of the port. It is defined as identity-ref.
                  If more speeds are introduced, developers can define
                  new identies for them. Current speeds include 1M, 10M,
                 100M, 1G, 10G, 40G and 100G.";
           }
       }

       grouping fabric-attributes {
           description "Attributes of a fabric";




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           leaf fabric-id {
             type fabrictypes:fabric-id;
             description
              "An identifier for a fabric in a topology.
              This identifier can be generated when composing a fabric.
              The composition of a fabric can be achived by defining a
              RPC, which is left for vendor specific implementation and
              not provided in this model.";
           }

           leaf name {
               type string;
               description
                   "Name of the fabric";
           }

           leaf type {
               type fabrictypes:underlay-network-type;
               description
                   "The type of physical network that implements this
                   fabric.Examples are vlan, and trill.";
           }

           container vni-capacity {
             description "The range of the VNI(VXLAN Network Identifier
               defined in RFC 7348)s that the PoD uses.";

               leaf min {
                   type int32;
                   description
                       "The lower limit Vni.";
               }

               leaf max {
                   type int32;
                   description
                       "The upper limite Vni.";
               }
           }

           leaf description {
               type string;
               description
                   "Description of the fabric";
           }

           container options {
               description "Options of the fabric";



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               uses fabric-options;
           }

           list device-nodes {
               key device-ref;
               description "Device nodes that include in a fabric.";
               uses device-attributes;
           }

           list device-links {
               key link-ref;
               description "Links that include within a fabric.";
               uses link-attributes;
           }

           list device-ports {
               key port-ref;
               description "Ports that include in the fabric.";
               uses port-attributes;
           }

       }

       // augment statements

       augment "/nw:networks/nw:network/nw:network-types" {
       description
         "Introduce new network type for Fabric-based topology";

           uses fabric-network-type;
       }

       augment "/nw:networks/nw:network/nw:node" {
       when "/nw:networks/nw:network/nw:network-types/"
       +"fabric:fabric-network"{
           description
             "Augmentation parameters apply only for networks
              with fabric topology";
         }
           description "Augmentation for fabric nodes created by
           fabric topology.";

           container fabric-attributes {
               description
               "Attributes for a fabric network";

               uses fabric-attributes;
           }



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       }

     augment "/nw:networks/nw:network/nw:node/nt:termination-point" {
       when "/nw:networks/nw:network/nw:network-types/"
           +"fabric:fabric-network" {
           description
             "Augmentation parameters apply only for networks
              with fabric topology";
         }
           description "Augmentation for port on fabric.";

           container fport-attributes {
               config false;
               description
               "Attributes for fabric ports";
               uses fabrictypes:fabric-port;
           }
       }
   }
   <CODE ENDS>

5.  IANA Considerations

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

   URI:urn:ietf:params:xml:ns:yang:ietf-dc-fabric-types

   Registrant Contact: The IESG.

   XML: N/A; the requested URI is an XML namespace.

   URI:urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology

   Registrant Contact: The IESG.

   XML: N/A; the requested URI is an XML namespace.

   URI:urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology-state

   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]:





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   NOTE TO THE RFC EDITOR: In the list below, please replace references
   to "draft-ietf-i2rs-yang-dc-fabric-network-topology-09 (RFC form)"
   with RFC number when published (i.e.  RFC xxxx).

   Name: ietf-dc-fabric-types

   Namespace: urn:ietf:params:xml:ns:yang:ietf-dc-fabric-types

   Prefix: fabrictypes

   Reference: draft-ietf-i2rs-yang-dc-fabric-network-topology-09.txt
   (RFC form)

   Name: ietf-dc-fabric-topology

   Namespace: urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology

   Prefix: fabric

   Reference: draft-ietf-i2rs-yang-dc-fabric-network-topology-09.txt
   (RFC form)

   Name: ietf-dc-fabric-topology-state

   Namespace: urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology-state

   Prefix: sfabric

   Reference: draft-ietf-i2rs-yang-dc-fabric-network-topology-09.txt
   (RFC form)

6.  Security Considerations

   The YANG module defined in this document is designed to be accessed
   via network management protocols such as NETCONF [RFC6241] or
   RESTCONF [RFC8040].  The lowest NETCONF layer is the secure transport
   layer, and the mandatory-to-implement secure transport is Secure
   Shell (SSH) [RFC6242].  The lowest RESTCONF layer is HTTPS, and the
   mandatory-to-implement secure transport is TLS [RFC5246].

   The NETCONF access control model [RFC8341] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.  The subtrees and data nodes and their
   sensitivity/vulnerability in the ietf-dc-fabric-topology module are
   as follows:





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   fabric-attributes: A malicious client could attempt to sabotage the
   configuration of important fabric attributes, such as device-nodes or
   type.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  The subtrees and data nodes and
   their sensitivity/vulnerability in the ietf-dc-fabric-topology module
   are as follows:

   fport-attributes: A malicious client could attempt to read the
   connections of fabrics without permission, such as device-port, name.

7.  Acknowledgements

   We wish to acknowledge the helpful contributions, comments, and
   suggestions that were received from Alexander Clemm, Donald E.
   Eastlake, Xufeng Liu, Susan Hares, Wei Song, Luis M.  Contreras and
   Benoit Claise.

8.  References

8.1.  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>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <http://www.rfc-editor.org/info/rfc3688>.

   [RFC5246]  Dierks, T. and E. Rescorla, "Transport Layer Security
              (TLS) Protocol Version 1.2", August 2008,
              <http://www.rfc-editor.org/info/rfc5246>.

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

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






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   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", June 2011,
              <http://www.rfc-editor.org/info/rfc6242>.

   [RFC7950]  Bjorklund, M., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, Auguest 2016.

   [RFC8040]  Bierman, A., Bjorklund, B., and K. Watsen, "RESTCONF
              Protocol", Jan 2017,
              <http://www.rfc-editor.org/info/rfc8040>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <http://www.rfc-editor.org/info/rfc8174>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol Access Control Model", March 2018,
              <http://www.rfc-editor.org/info/rfc8341>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore
              Architecture", RFC 8342, March 2018.

   [RFC8345]  Clemm, A., Medved, J., Tkacik, T., Varga, R., Bahadur, N.,
              and H. Ananthakrishnan, "A YANG Data Model for Network
              Topologies", RFC 8345, March 2018,
              <http://www.rfc-editor.org/info/rfc8345>.

8.2.  Informative References

   [I-D.draft-ietf-nvo3-geneve]
              Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic
              Network Virtualization Encapsulation", I-D draft-ietf-
              nvo3-geneve-06, March 2018.

   [RFC7348]  Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
              L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
              eXtensible Local Area Network (VXLAN): A Framework for
              Overlaying Virtualized Layer 2 Networks over Layer 3
              Networks", August 2014,
              <http://www.rfc-editor.org/info/rfc7348>.

   [RFC8340]  Bjorklund, M. and L. Berger, "YANG Tree Diagrams",
              RFC 8340, March 2018,
              <http://www.rfc-editor.org/info/rfc8340>.






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   [RFC8344]  Bjorklund, M., "A YANG Data Model for IP Management",
              RFC 8344, March 2018,
              <http://www.rfc-editor.org/info/rfc8344>.

   [RFC8346]  Clemm, A., Medved, J., Tkacik, T., Liu, X., Bryskin, I.,
              Guo, A., Ananthakrishnan, H., Bahadur, N., and V. Beeram,
              "A YANG Data Model for Layer 3 Topologies", RFC 8346,
              March 2018, <http://www.rfc-editor.org/info/rfc8346>.

Appendix A.  Non NMDA -state modules

   The YANG module ietf-dc-fabric-toplogy defined in this document
   augments two modules, ietf-network and ietf-network-topology, that
   are designed to be used in conjunction with implementations that
   support the Network Management Datastore Architecture (NMDA) defined
   in [RFC8342].  In order to allow implementations to use the model
   even in case when NMDA is not supported, a set of companion modules
   have been defined that represent a state model of networks and
   network topologies, ietf-network-state and ietf-network-topology-
   state, respectively.

   In order to be able to use the model for fabric topologies defined in
   this in this document in conjunction with non-NMDA compliant
   implementations, a corresponding companion module needs to be
   introduced as well.  This companion module, ietf-dc-fabric-topology-
   state, mirrors ietf-dc-fabric-topology.  However, the module augments
   ietf-network-state (instead of ietf-network and ietf-network-
   topology) and all of its data nodes are non-configurable.

   Like ietf-network-state and ietf-network-topology-state, ietf-dc-
   fabric-topology-state SHOULD NOT be supported by implementations that
   support NMDA.  It is for this reason that the module is defined in
   the Appendix.

   The definition of the module follows below.  As the structure of the
   module mirrors that of its underlying module, the YANG tree is not
   depicted separately.

   <CODE BEGINS>
   file "ietf-dc-fabric-topology-state@2018-04-16.yang"
       module ietf-dc-fabric-topology-state {

       yang-version 1.1;
       namespace
       "urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology-state";
       prefix sfabric;

       import ietf-network-state {



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           prefix nws;
           reference
           "RFC 8345:A Data Model for Network Topologies";
       }
       import ietf-dc-fabric-types {
           prefix fabrictypes;

           reference
           "draft-ietf-i2rs-yang-dc-fabric-network-topology-09
           NOTE TO RFC EDITOR:
           (1) Please replace above reference to draft-ietf-i2rs-yang
           -dc-fabric-network-topology-09 with RFC number when
           published (i.e. RFC xxxx).
           (2) Please replace the data in the revision statement
           with the data of publication when published.";
       }

       organization
       "IETF I2RS (Interface to the Routing System) Working Group";

       contact
       "WG Web:    <http://tools.ietf.org/wg/i2rs/ >
        WG List:   <mailto:i2rs@ietf.org>

        Editor:    Yan Zhuang
                   <mailto:zhuangyan.zhuang@huawei.com>

        Editor:    Danian Shi
                   <mailto:shidanian@huawei.com>";


       description
           "This module contains a collection of YANG definitions for
           Fabric state, representing topology that is either learned,
           or topology that results from applying toplogy that has been
           configured per the ietf-dc-fabric-topology model, mirroring
           the corresponding data nodes in this model.

           This model mirrors the configuration tree of ietf-dc-fabric
           -topology, but contains only read-only state data. The model
           is not needed when the implemtation infrastructure supports
           the Network Management Datastore Architecture(NMDA).

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

           Redistribution and use in source and binary forms, with or
           without modification, is permitted pursuant to, and subject



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           to the license terms contained in, the Simplified BSD
           License set forth in Section 4.c of the IETF Trust's Legal
           Provisions Relating to IETF Documents
           (http:s//trustee.ietf.org/license-info).

           This version of this YANG module is part of
           draft-ietf-i2rs-yang-dc-fabric-network-topology;
           see the RFC itself for full legal notices.

           NOTE TO RFC EDITOR: Please replace above reference to
           draft-ietf-i2rs-yang-dc-fabric-network-topology-09 with RFC
           number when published (i.e. RFC xxxx).";

           revision "2018-04-16"{
               description
                   "Initial revision.
                    NOTE TO RFC EDITOR:
                    Please replace the following reference to
                    draft-ietf-i2rs-yang-dc-fabric-network-topology-09
                    with RFC number when published (i.e. RFC xxxx).";
               reference
                 "draft-ietf-i2rs-yang-dc-fabric-network-topology-09";
           }


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

       grouping fabric-options {
           description "Options for a fabric";

           leaf gateway-mode {
               type enumeration {
                   enum centralized {
                       description "The Fabric uses centerilized
                       gateway, in which gateway is deployed on SPINE
                       node.";
                   }
                   enum distributed {
                       description "The Fabric uses distributed



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                       gateway, in which gateway is deployed on LEAF
                       node.";
                   }
               }
               default "distributed";
               description "Gateway mode of the fabric";
           }

           leaf traffic-behavior {
               type enumeration {
                   enum normal {
                       description "Normal means no policy is needed
                       for all traffic";
                   }
                   enum policy-driven {
                       description "Policy driven means policy is
                       needed for the traffic otherwise the traffic
                       will be discard.";
                   }
               }
               default "normal";
               description "Traffic behavior of the fabric";
           }

           leaf-list capability-supported {
               type fabrictypes:service-capabilities;
               description
                   "It provides a list of supported services of the
                   fabric. The service-capabilities is defined as
                   identity-ref. Developers can define more services
                   by defining new identies.";
           }
       }

       grouping device-attributes {
           description "device attributes";
           leaf device-ref {
               type fabrictypes:node-ref;
               description
                   "The device that the fabric includes which refers
                    to a node in another topolopogy.";
           }
           leaf-list role {
               type fabrictypes:device-role;
               default fabrictypes:leaf;
               description
                   "It is a list of devce-role to represent the roles
                   that a device plays within a PoD, such as SPINE,



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                   LEAF, Border, or Border-Leaf.
                   The device-role is defined as identity-ref. If more
                   than 2 stage is used for a PoD, developers can
                   define new identities for the device-role.";
           }
       }

       grouping link-attributes {
           description "Link attributes";
           leaf link-ref {
               type fabrictypes:link-ref;
               description
                   "The link that the fabric includes which refers to
                   a link in another topology.";
           }
       }

       grouping port-attributes {
           description "Port attributes";
           leaf port-ref {
               type fabrictypes:tp-ref;
               description
                   "The port that the fabric includes which refers to
                   a termination-point in another topology.";
           }
           leaf port-type {
               type fabrictypes:port-type;
               description
                   "Port type is defined as identiy-ref. If current
                   types includes ethernet or serial. If more types
                   are needed, developers can define new identities.";
           }
           leaf bandwidth {
               type fabrictypes:bandwidth;
               description
                   "Bandwidth of the port. It is defined as
                   identity-ref. If more speeds are introduced,
                   developers can define new identies for them.
                   Current speeds include 1M, 10M, 100M, 1G, 10G,
                   40G and 100G.";
           }
       }

       grouping fabric-attributes {
           description "Attributes of a fabric";

           leaf fabric-id {
                   type fabrictypes:fabric-id;



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                   description
                       "Fabric id";
           }

           leaf name {
               type string;
               description
                   "Name of the fabric";
           }

           leaf type {
               type fabrictypes:underlay-network-type;
               description
                   "The type of physical network that implements this
                   fabric.Examples are vlan, and trill.";
           }

           container vni-capacity {
               description "The range of the VNI(VXLAN Network
               Identifier defined in RFC 7348)s that the PoD uses.";

               leaf min {
                   type int32;
                   description
                       "The lower limit Vni.";
               }

               leaf max {
                   type int32;
                   description
                       "The upper limite Vni.";
               }
           }

           leaf description {
               type string;
               description
                   "Description of the fabric";
           }

           container options {
               description "Options of the fabric";
               uses fabric-options;
           }

           list device-nodes {
               key device-ref;
               description "Device nodes that include in a fabric.";



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               uses device-attributes;
           }

           list device-links {
               key link-ref;
               description "Links that include within a fabric.";
               uses link-attributes;
           }

           list device-ports {
               key port-ref;
               description "Ports that include in the fabric.";
               uses port-attributes;
           }
       }

       // augment statements

       augment "/nws:networks/nws:network/nws:network-types" {
         description
           "Introduce new network type for Fabric-based logical
           topology";
         uses fabric-network-type;
       }

       augment "/nws:networks/nws:network/nws:node" {
         when "/nws:networks/nws:network/nws:network-types"
         +"/sfabric:fabric-network"{
           description "Augmentation parameters apply only for
           networks with fabric topology.";
         }
         description "Augmentation for fabric nodes.";
         container fabric-attributes-state {
           description
             "Attributes for a fabric network";
           uses fabric-attributes;
         }
       }
   }
   <CODE ENDS>

Authors' Addresses









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   Yan Zhuang
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: zhuangyan.zhuang@huawei.com


   Danian Shi
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: shidanian@huawei.com


   Rong Gu
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing, Beijing  100053
   China

   Email: gurong_cmcc@outlook.com


   Hariharan Ananthakrishnan
   Packet Design

   Email: hari@packetdesign.com




















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