\
Network Working Group                                          D. Shytyi
Internet-Draft                                                       SFR
Intended status: Informational                        September 21, 2019
Expires: March 24, 2020


                   A YANG Module for uCPE management.
                      draft-shytyi-opsawg-vysm-00

Abstract

   This document provides a YANG data model for uCPE management (VYSM)
   and definition of the uCPE equipment.  The YANG Service Model serves
   as a base framework for managing an universal Customer-Premises
   Equipment (uCPE) subsystem.  The model can be used by a Network
   Service Orchestrator.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on March 24, 2020.

Copyright Notice

   Copyright (c) 2019 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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Universal CPE . . . . . . . . . . . . . . . . . . . . . . . .   2
   4.  YANG Service Model for uCPE management  . . . . . . . . . . .   4
   5.  uCPE YANG Service Model tree diagram overview . . . . . . . .   5
   6.  Specification of the VNF YANG Service Model . . . . . . . . .   6
   7.  XML example . . . . . . . . . . . . . . . . . . . . . . . . .  10
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Network Function Virtualization is a technology that allows to
   virtualize the network services running on dedicaded hardware.  This
   technology became a base for universal Customer-Premises Equipment
   (uCPE).  This document defines the uCPE as harware with x86
   capabilities that has a hypervisor.  In other words, uCPE is a host
   that may run multiple Virtual Machines with guest OSs, where each
   Guest OS may represent a Physical Network Function.  This document
   presents the YANG Service Model (VYSM) to manage from an Orchestrator
   the infrastructure inside the uCPE.

2.  Terminology

   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].

   Link - is an entity that enables link layer communication of nodes.

   Port - node connector to the link.

   NE - Network Element.

   NSYM - Network Service Yang Module.

   VYSM - VNF YANG Service Model.

3.  Universal CPE

   Firstly, this document defines the platform that is controlled with
   VYSM - universal CPE (uCPE).  The uCPE as harware with x86
   capabilities that is generally running Linux distibution with



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   additinal virtualisation layer.  Virtualization layer provides
   virtual compute, virtual storage and virtual network resources.  Each
   VNF runnning in the uCPE requires the amount of virtual resources
   (for example: 4 vCPUs, 4GB RAM, 40GB storege, 4 vPorts).  VNFs MAY be
   interconnected between each other and physical ports via Virtual
   Networks.  Topology construction and VM lifecycle management is
   allowed via high level interface (Configuration can be done in the
   same transaction).  The figure below presents the uCPE architecture.


         ----------------------------------------|--------------
         VNF1            VNF2            VNF3    |
         ----------------------------------------|
         Virtual         Virtual         Virtual | uCPE software
         Compute         Storage         Networks|
         ----------------------------------------|---------------
         PHY x86         RAM+PHY         PHYsical| uCPE Hardware
         processor       storage         ports   |




   The next elements can be managed in the uCPE:

   o  Virtual Network Funcitons:

      *  Number of assigned vCPUs.

      *  Size of allocated RAM.

      *  VNF day0 config (bootstrap).

      *  vLinks that are attached to the VNF.

   o  Virtual Switches:

      *  vLinks that are attached to the vSW.

   o  Virtual Links(vLinks).

   o  Physical Ports of the uCPE.

   The VNF in the uCPE could be a vRouter or vFirewall or an SD-WAN that
   is not a default part of virtual network resources of the uCPE.  We
   can have multiple VNFs instantiated in the uCPE.  With support of
   links and swithes, VNFs may participate a service chains.  Example of
   service chains:




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   o  vSW(WAN)-l1-vRouter(vCPE)-l2-vSW(Service)-l3-vFirewall-
      l4-vSW(LAN).

   o  vSW(WAN)-l1-SDWAN-l2-vSW(Service)-l3-vFirewall-l4-vSW(LAN).

4.  YANG Service Model for uCPE management

   Secondly, this document defines and classifies the VYSM as Network
   Service YANG Module(NSYM) layer component RFC 8199 [RFC8199].  Thus
   it inherits the characteristics of the NSYM Layer.  VYSM is a modeled
   representation of the specific service requirements.  It provides
   abstraction of services configuration and operations that MAY be
   implemented in Network Elemets (NEs).  Thus VYSM does not describe
   all configuration to be performed on the devices, but provides the
   configuration that is required for the "Network Service to Network
   Element(s)" decomposition process RFC 8199 [RFC8199].  Example of the
   decomposition is presented in the figure below.

   The Network Service YANG module exposes the configuration commands
   via the Northbound interfaces of the orchestrator.  Therefore the set
   of the commands modeled in the VYSM can be inputed via Notrhbound
   interfaces(for example CLI).  In the example the command "vm VNF1" is
   passed via Northbound interface to the orchestrator.  It defines the
   virtual machine name.  Further the same configuration MAY be
   transormed to the one or multiple Network Element payloads (for
   example xml for NETCONF) that carry an equivalent of commands such as
   "nf nf-name VNF1"
























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                                +-+-+-+-+-+-+-+-+-+
                                |                 |
                                |  config t       |
                                |      vm VNF1    |
                                +-+-+-+-+-+-+-+-+-+
                                         #
                                         #
   ++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   :                                                                   :
   :  +-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+                             :
   :  |  Network Service YANG Module     |                             :
   :  +-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+                             :
   :                   #                                               :
   :     ##############################               orchestrator     :
   :     #             #              #                                :
   : '---------' '------------' '-----------'                          :
   : 'Module1  ' ' Module 2   ' '  Module3  ' <= Network Element       :
   : '---------' '------------' '-----------'    YANG Modules          :
   :      #             #               #                              :
   :      #             #               #######################        :
   :      ####          ##############                        #        :
   :         #                       #                        #        :
   ++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             #                       #                        #
    Network  #  element 1    Network # element 2      Network # element3
   ++-+-+-+-+-+-+-+-+-+-+  -+-+-+-++-+-+-+-+-+-+-+-+-  +-+-+-+-+-+-+-+-+
   | domains domain VNF1|  |tenants tenant name VNF1|  |nf nf-name VNF1|
   ++-+-+-+-+-+-+-+-+-+-+  -+-+-+-++-+-+-+-+-+-+-+-+-  +-+-+-+-+-+-+-+-+



5.  uCPE YANG Service Model tree diagram overview

   This section provides an overview of the Service YANG Model (VSYM)
   that MAY be made with "pyang" utility.  The figure below presents the
   tree diagram of VYSM.















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             module: ietf-ucpe
                 +--rw ucpe* [name]
                    +--rw name             string
                    +--rw links* [link]
                    |  +--rw link    string
                    +--rw phyInterfaces* [interface]
                    |  +--rw interface    string
                    |  +--rw ports* [port]
                    |     +--rw port    string
                    |     +--rw link?   -> ../../../links/link
                    +--rw switches* [switch]
                    |  +--rw switch    string
                    |  +--rw ports* [port]
                    |     +--rw port    string
                    |     +--rw name?   string
                    |     +--rw link?   -> ../../../links/link
                    +--rw vms* [vm]
                       +--rw vm             string
                       +--rw ports* [port]
                       |  +--rw port    string
                       |  +--rw name?   string
                       |  +--rw link?   -> ../../../links/link
                       +--rw ram?           uint64
                       +--rw cpu?           uint64
                       +--rw storages* [id]
                       |  +--rw id          string
                       |  +--rw location?   string
                       +--rw day0-config
                          +--rw location?        string
                          +--rw day0-var-path?   string
                          +--rw variable* [name]
                             +--rw name     string
                             +--rw value?   string


6.  Specification of the VNF YANG Service Model

   This section presents the specification of the VYSM.


   <CODE BEGINS> file "ietf-ucpe@2019-09-16.yang"
   module ietf-ucpe {
     namespace "urn:ietf:params:xml:ns:yang:ietf-ucpe";
     prefix ietf-ucpe;
           organization
           "SFR";
           contact
                   "Dmytro Shytyi



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                   EMail:ietf.dmytro@shytyi.net";
           description
                   "This YANG Service Model for uCPE management.";
           revision 2018-07-01 {
                   description
                   "Initial revision.";
                   reference
           "draft-shytyi-netmod-vysm-01";
           }
           revision 2019-09-16{
                   description
                   "Added 0day config for VNFs.
                   Yang model modified according
                   to the received comments.";
                   reference
           "draft-shytyi-opsawg-vysm-00";
           }

     list ucpe{
       key name;
       leaf name {
                   type string;
                   description "ID of uCPE where
                   a service is instantiated";
       }
     list links{
                   key link;
                   leaf link{
                           type string;
                   description "Name of the virtual link from the pool
                   of the links";
                   }
             description "Pool of the virtual links that connect VMs and
             Interfaces";
           }
           list phyInterfaces{
                   key interface;
                   leaf interface{
                           type string;
                            description "Name of physical interface";
                   }
                   list ports{
                           key port;
                           leaf port{
                                   type string;
                           description "Name of the connector";
                           }
                           leaf link{



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                                   type leafref{
                                           path "../../../links/link";
                                   }
                             description "Link that is connected to
                             the port via connector";
                           }
                           description "Set of the connectors the
                           physical interface has";
                   }
                   description "Set of physical interfaces";
           }
           list switches{
             key switch;
                   leaf switch{
                           type string;
                           description "Name of the forwarding domain";
                   }
                   list ports{
                           key port;
                           leaf port{
                                   type string;
                                   description "Name of the connector";
                           }
                           leaf name{
                             type string;
                                   description "Name of the
                                   subconnector";
                           }
                           leaf link{
                                   type leafref{
                                           path "../../../links/link";
                                   }
                           description "Link that is connected to the
                           switch via port";
                           }
                     description "Set of the connectors the
                     forwarding domain has";
                   }
                   description "Set of the forwarding domains";

           }

           list vms{
                   key vm;
                   leaf vm{
                           type string;
                   description "ID of the Virtual Machine";
                   }



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                   list ports{
                           key port;
                           leaf port{
                                   type string;
                                   description "Name of the connector";
                           }
                           leaf name{
                                   type string;
                                   description "Name of
                                   the subconnector";
                           }
                           leaf link{
                                   type leafref{
                                           path "../../../links/link";
                                   }
                                   description "Link that connects the
                                   VM with a switch or Interface
                                   via connector";
                           }
                     description "Set of Virtual Machine connectors";
                   }

                   leaf ram{
                           type uint64;
                           description "Size of RAM to allocate for
                           the Guest OS";
                   }
                   leaf cpu{
                           type uint64;
                           description "Number of vCPUs to
                           allocate for the Guest OS";
                   }
                   list storages{
                           key id;
                           leaf id{
                                   type string;
                                   description "Number of
                                   vDisk attached to the VM";
                           }
                           leaf location{
                                   type string;
                                   description "External location where
                                   the image (ex.qcow2) is saved.";
                           }
                           description "Virtual storge/vDisk
                           attached to the Virtual Machine";
                   }
                   container day0-config{



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                         leaf location{
                           type string;
                           description "0day configuration location";
                         }
                         leaf day0-var-path{
                           type string;
                           description "path of the file
                           that contains the 0day variables";
                         }
                         list variable{
                           key name;
                           leaf name{
                             type string;
                             description "variable name";
                           }
                           leaf value{
                             type string;
                             description "variable value";
                             }
                         description "list of variables";
                         }
                         description "0day configuration:init config";

                   }
                   description "Set of the Virtual Machines configured
                   on the universal Customer-Premises Equipment";
           }
           description "This is an uCPE management service";
     }
    }
   <CODE ENDS>


7.  XML example

   The XML example below presents the configuration of the next service
   in the uCPE, where: vSW(LAN), vSW(WAN), vSW(Service) - virtual
   switches; l1,l2,l3,l4 - virtual links; VMs represent PNFs (Physical
   Network Fuctions) that could be bootstrapped with 0day config/
   license.











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            +--------+      +-------------+      +------------+
            |vSW(LAN)|--l2--|VNF-vFirewall|--l3--|            |
            +--------+      +-------------+      |            |
            +--------+      +-------------+      |vSW(Service)|
            |vSW(WAN)|--l1--|   VNF_vCPE  |--l4--|            |
            +--------+      +-------------+      +------------+



     <ucpe xmlns="urn:ietf:params:xml:ns:yang:ietf-ucpe">
         <name>ucpe1</name>
         <links>
           <link>l1</link>
         </links>
         <links>
           <link>l2</link>
         </links>
         <links>
           <link>l3</link>
         </links>
         <links>
           <link>l4</link>
         </links>
         <switches>
           <switch>lan</switch>
           <ports>
             <port>10</port>
             <name>l2p10</name>
             <link>l2</link>
           </ports>
         </switches>
         <switches>
           <switch>service</switch>
           <ports>
             <port>10</port>
             <name>l3p10</name>
             <link>l3</link>
           </ports>
           <ports>
             <port>11</port>
             <name>l4p10</name>
             <link>l4</link>
           </ports>
         </switches>
         <switches>
           <switch>wan</switch>
           <ports>
             <port>10</port>



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             <link>l1</link>
           </ports>
         </switches>
         <vms>
           <vm>VNF-vCPE</vm>
           <ports>
             <port>1</port>
             <name>l1p1</name>
             <link>l1</link>
           </ports>
           <ports>
             <port>2</port>
             <name>l4p2</name>
             <link>l4</link>
           </ports>
           <ram>2048</ram>
           <cpu>2</cpu>
           <storages>
             <id>1</id>
             <location>http://192.168.2.1/vCPE-x86.qcow2</location>
           </storages>
           <day0-config>
             <location>https://192.168.2.1/vCPE-day0.iso</location>
             <day0-var-path>/config.rom</day0-var-path>
             <variable>
               <name>hostname</name>
               <value>IETF-vCPE</value>
             </variable>
             <variable>
               <name>ipaddress</name>
               <value>192.168.1.2 255.255.255.0</value>
             </variable>
           </day0-config>
         </vms>
         <vms>
           <vm>VNF-vFirewall</vm>
           <ports>
             <port>1</port>
             <name>l3p1</name>
             <link>l3</link>
           </ports>
           <ports>
             <port>2</port>
             <name>l2p2</name>
             <link>l2</link>
           </ports>
           <ram>2048</ram>
           <cpu>2</cpu>



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           <storages>
             <id>1</id>
             <location>http://192.168.2.1/vFirewall-x86.qcow2</location>
           </storages>
           <day0-config>
             <location>https://192.168.2.1/vFirewall-day0.iso</location>
             <day0-var-path>/config.rom</day0-var-path>
             <variable>
               <name>hostname</name>
               <value>vFirewall</value>
             </variable>
             <variable>
               <name>ipaddress</name>
               <value>192.168.1.3 255.255.255.0</value>
             </variable>
           </day0-config>
         </vms>
       </ucpe>


8.  Security Considerations

   At this time, no security considerations are addressed by this memo.

9.  IANA Considerations

   No request to IANA at this time.

10.  Acknowledgements

   The authors would like to thank:

   o  Mahesh Jethanandani.

   o  Robert Varga.

   o  Bill Wu

   for their valuable comments.

11.  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,
              <https://www.rfc-editor.org/info/rfc2119>.





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   [RFC8199]  Bogdanovic, D., Claise, B., and C. Moberg, "YANG Module
              Classification", RFC 8199, DOI 10.17487/RFC8199, July
              2017, <https://www.rfc-editor.org/info/rfc8199>.

Author's Address

   Dmytro Shytyi
   SFR
   Paris area , Ile-de-France
   France

   Email: ietf.dmytro@shytyi.net
   URI:   https://dmytro.shytyi.net






































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