TEAS Working Group                                           Y. Lee, Ed.
Internet-Draft                                       Samsung Electronics
Intended status: Standards Track                           D. Dhody, Ed.
Expires: 27 April 2022                                    S. Karunanithi
                                                     Huawei Technologies
                                                              R. Vilalta
                                                                    CTTC
                                                                 D. King
                                                    Lancaster University
                                                           D. Ceccarelli
                                                                Ericsson
                                                         24 October 2021


   YANG models for VN/TE Performance Monitoring Telemetry and Scaling
                           Intent Autonomics
            draft-ietf-teas-actn-pm-telemetry-autonomics-07

Abstract

   This document provides YANG data models that describe performance
   monitoring telemetry and scaling intent mechanisms for TE-tunnels and
   Virtual Networks (VNs).

   The models presented in this document allow customers to subscribe to
   and monitor the key performance data of the TE-tunnel or the VN.  The
   models also provide customers with the ability to program autonomic
   scaling intent mechanisms on the level of TE-tunnel as well as VN.

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 27 April 2022.






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Copyright Notice

   Copyright (c) 2021 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 the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   4
     1.3.  Prefixes in Data Node Names . . . . . . . . . . . . . . .   4
   2.  Use-Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Design of the Data Models . . . . . . . . . . . . . . . . . .   7
     3.1.  TE Telemetry Model  . . . . . . . . . . . . . . . . . . .   7
     3.2.  VN Telemetry Model  . . . . . . . . . . . . . . . . . . .   8
     3.3.  VPN Service Performance Monitoring  . . . . . . . . . . .   9
   4.  Autonomic Scaling Intent Mechanism  . . . . . . . . . . . . .  10
   5.  Notification  . . . . . . . . . . . . . . . . . . . . . . . .  12
     5.1.  YANG Push Subscription Examples . . . . . . . . . . . . .  12
     5.2.  Scaling Examples  . . . . . . . . . . . . . . . . . . . .  14
   6.  YANG Data Tree  . . . . . . . . . . . . . . . . . . . . . . .  17
   7.  YANG Data Model . . . . . . . . . . . . . . . . . . . . . . .  20
     7.1.  ietf-te-telemetry model . . . . . . . . . . . . . . . . .  20
     7.2.  ietf-vn-telemetry model . . . . . . . . . . . . . . . . .  27
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  32
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  33
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  34
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  34
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  34
     11.2.  Informative References . . . . . . . . . . . . . . . . .  36
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  36











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1.  Introduction

   The YANG [RFC7950] model in [I-D.ietf-teas-actn-vn-yang] is used to
   operate customer-driven Virtual Networks (VNs) during the computation
   of VN, its instantiation, and its life-cycle service management and
   operations.  YANG model in [I-D.ietf-teas-yang-te] is used to operate
   TE-tunnels during the tunnel instantiation, and its life-cycle
   management and operations.

   The models presented in this draft allow the applications hosted by
   the customers to subscribe to and monitor their key performance data
   of their interest on the level of VN [I-D.ietf-teas-actn-vn-yang] or
   TE-tunnel [I-D.ietf-teas-yang-te].  The key characteristic of the
   models presented in this document is a top-down programmability that
   allows the applications hosted by the customers to subscribe to and
   monitor key performance data of their interest and autonomic scaling
   intent mechanism on the level of VN as well as TE-tunnel.

   According to the classification of [RFC8309], the YANG data models
   presented in this document can be classified as customer service
   models.  These can be mapped to the CMI (Customer Network Controller
   (CNC)- Multi-Domain Service Coordinator (MSDC) interface) of ACTN
   [RFC8453].

   [RFC8233] describes key network performance data to be considered for
   end-to-end path computation in TE networks.  The services provided
   can be optimized to meet the requirements (such as traffic patterns,
   quality, and reliability) of the applications hosted by the
   customers.

   This document provides YANG data models generically applicable to any
   VN/TE-Tunnel service clients to provide an ability to program their
   customized performance monitoring subscription and publication data
   models and automatic scaling in/out intent data models.  These models
   can be utilized by a client network controller to initiate the
   capabilities to a TE network controller communicating with the client
   controller via a NETCONF [RFC8341] or a RESTCONF [RFC8040] interface.

   The term performance monitoring is used in this document in a
   different from how the term has been used in TE networks for many
   years.  Performance monitoring in this document refers to
   subscription and publication of streaming telemetry data.
   Subscription is initiated by the client (e.g., CNC) while publication
   is provided by the network (e.g., MDSC/Provisioning Network
   Controller (PNC)) based on the client's subscription.  As the scope
   of performance monitoring in this document is telemetry data on the
   level of a client's VN or TE-tunnel, the entity interfacing to the
   client (e.g., MDSC) has to provide VN or TE-tunnel level information.



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   This requires the controller to have the capability to derive VN or
   TE-tunnel level performance data based on lower-level data collected
   via PM counters in the Network Elements (NE).  How the controller
   entity derives such customized level data (i.e., VN or TE-tunnel
   level) is out of the scope of this document.

   The data model includes configuration and state data according to the
   Network Management Datastore Architecture (NMDA) [RFC8342].

1.1.  Terminology

   Refer to [RFC8453], [RFC7926], and [RFC8309] for the key terms used
   in this document.

   Scaling: This refers to the network's ability to re-shape its own
   resources.  "Scale out" refers to improve network performance by
   increasing the allocated resources, while "scale in" refers to
   decreasing the allocated resources, typically because the existing
   resources are unnecessary.

   Scaling Intent: Scaling intent is used to declare scaling conditions.
   Specifically, scaling intent refers to how the client programs or
   configures conditions that will be applied to their key performance
   data to trigger either scaling out or scaling in.  Various conditions
   can be set for scaling intent on either VN or TE-tunnel level.

   Network Autonomics: This refers to the network automation capability
   that allows a client to initiate scaling intent mechanisms and
   provides the client with the status of the adjusted network resources
   based on the client's scaling intent in an automated fashion.

1.2.  Tree Diagram

   A simplified graphical representation of the data model is used in
   Section 4 and Section 6 of this document.  The meaning of the symbols
   in these diagrams is defined in [RFC8340].

1.3.  Prefixes in Data Node Names

   In this document, names of data nodes and other data model objects
   are prefixed using the standard prefix associated with the
   corresponding YANG imported modules, as shown in Table 1.









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      +==========+===================+==============================+
      | Prefix   | YANG module       | Reference                    |
      +==========+===================+==============================+
      | te       | ietf-te           | [I-D.ietf-teas-yang-te]      |
      +----------+-------------------+------------------------------+
      | te-types | ietf-te-types     | [RFC8776]                    |
      +----------+-------------------+------------------------------+
      | te-tel   | ietf-te-telemetry | [RFCXXXX]                    |
      +----------+-------------------+------------------------------+
      | vn       | ietf-vn           | [I-D.ietf-teas-actn-vn-yang] |
      +----------+-------------------+------------------------------+
      | vn-tel   | ietf-vn-telemetry | [RFCXXXX]                    |
      +----------+-------------------+------------------------------+

              Table 1: Prefixes and corresponding YANG modules

   Note: The RFC Editor is requested to replace XXXX with the number
   assigned to the RFC once this draft becomes an RFC, and to remove
   this note.

   Further, the following additional documents are referenced in the
   model defined in this document -

   *  [RFC7471] - OSPF Traffic Engineering (TE) Metric Extensions.

   *  [RFC8570] - IS-IS Traffic Engineering (TE) Metric Extensions.

   *  [RFC7823] - Performance-Based Path Selection for Explicitly Routed
      Label Switched Paths (LSPs) Using TE Metric Extensions.

2.  Use-Cases

   There is a need for real-time (or semi-real-time) traffic monitoring
   of the network to optimize the network and the traffic distribution.
   Figure 1 shows the high-level workflow for dynamic service control
   based on traffic monitoring.















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      +----------------------------------------------+
      | Client   +-----------------------------+     |
      |          | Dynamic Service Control APP |     |
      |          +-----------------------------+     |
      +----------------------------------------------+
      1.Traffic|  /|\4.Traffic            | /|\
      Monitor &|   | Monitor              |  | 8.Traffic
      Optimize |   | Result     5.Service |  | modify &
      Policy   |   |              modify &|  | optimize
              \|/  |        optimize Req.\|/ | result
      +----------------------------------------------+
      | Orchestrator                                 |
      |    +-------------------------------+         |
      |    |Dynamic Service Control Agent  |         |
      |    +-------------------------------+         |
      |    +---------------+ +-------------------+   |
      |    | Flow Optimize | | vConnection Agent |   |
      |    +---------------+ +-------------------+   |
      +----------------------------------------------+
      2. Path |   /|\3.Traffic            | /|\
      Monitor |    | Monitor              |  |7.Path
      Request |    | Result      6.Path   |  | modify &
              |    |             modify & |  | optimize
             \|/   |        optimize Req.\|/ | result
      +----------------------------------------------+
      | Network SDN Controller                       |
      |  +----------------------+ +-----------------+|
      |  | Network Provisioning | |Abstract Topology||
      |  +----------------------+ +-----------------+|
      |  +------------------+ +--------------------+ |
      |  |Network Monitoring| |Physical Topology DB| |
      |  +------------------+ +--------------------+ |
      +----------------------------------------------+

   APP: Application
   DB: Database
   Req: Request

      Figure 1: Workflow for dynamic service control based on traffic
                                 monitoring

   Some of the key points are as follows:









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   *  Network traffic monitoring is important to facilitate automatic
      discovery of the imbalance of network traffic, and initiate
      network optimization, thus helping the network operator or the
      virtual network service provider to use the network more
      efficiently and save Capital Expense (CAPEX) and Operating Expense
      (OPEX).

   *  Customer services have various Service Level Agreement (SLA)
      requirements, such as service availability, latency, jitter,
      packet loss rate, Bit Error Rate (BER), etc.  The TE network can
      satisfy service availability and BER requirements by providing
      different protection and restoration mechanisms.  However, for
      other SLA requirements, there are no such mechanisms.  In order to
      provide high quality services according to the customer SLA, one
      possible solution is to measure the SLA related performance
      parameters, and dynamically provision and optimize services based
      on the performance monitoring results.

   *  Performance monitoring in a large scale network could generate a
      huge amount of performance information.  Therefore, the
      appropriate way to deliver the information at the client and
      network interfaces should be carefully considered.

3.  Design of the Data Models

   This document describes two YANG models:

   (i)    TE Telemetry Model which provides the TE-Tunnel level of

          performance monitoring mechanism and scaling intent mechanism
          that allows scale in/out programming by the customer.  (See
          Section 3.1 & Section 7.1 for details).

   (ii)   VN Telemetry Model which provides the VN level of the

          aggregated performance monitoring mechanism and scaling intent
          mechanism that allows scale in/out programming by the customer
          (See Section 3.2 & Section 7.2 for details).

3.1.  TE Telemetry Model

   This model describes the performance telemetry for the TE tunnel.
   The telemetry data is augmented to the TE tunnel.  This model also
   allows autonomic traffic engineering scaling intent configuration
   mechanism on the TE-tunnel level.  Various conditions can be set for
   auto-scaling based on the telemetry data (See Section 5 for details)





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   As shown in Figure 2, the TE Telemetry Model augments the TE-Tunnel
   Model to enhance TE performance monitoring capability.  This
   monitoring capability will facilitate re-optimization and
   reconfiguration of TE tunnels based on the performance monitoring
   data collected via the TE Telemetry YANG model.

                +------------+          +--------------+
                |  TE-Tunnel |          |      TE      |
                |   Model    |<---------|  Telemetry   |
                +------------+ augments |     Model    |
                                        +--------------+

                 Figure 2: TE Telemetry Model Relationship

3.2.  VN Telemetry Model

   As shown in Figure 3, the VN Telemetry Model augments the basic VN
   model to enhance VN monitoring capability.  This monitoring
   capability will facilitate re-optimization and reconfiguration of VNs
   based on the performance monitoring data collected via the VN
   Telemetry YANG model.  This model also imports TE telemetry model to
   reuse the groupings.

                +----------+          +--------------+
                |    VN    | augments |      VN      |
                |   Model  |<---------|   Telemetry  |
                +----------+          |     Model    |
                                      +--------------+
                                             |
                                             | imports
                                             v
                                      +--------------+
                                      |      TE      |
                                      |   Telemetry  |
                                      |     Model    |
                                      +--------------+

                 Figure 3: VN Telemetry Model Relationships

   This model describes the performance telemetry for the VN model.  The
   telemetry data is augmented to the VN model at the VN Level as well
   as at the individual VN member level.  This model also allows
   autonomic traffic engineering scaling intent configuration mechanism
   on the VN level.  Scale in/out criteria might be used for network
   autonomics in order for the controller to react to a certain set of
   variations in monitored parameters (See Section 4 for illustrations).





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   Moreover, this model also provides a mechanism to define aggregated
   VN telemetry parameters as a grouping of underlying VN-member level
   telemetry parameters.  This is unique to the VN model as a VN is made
   up of multiple VN-members and further each VN-member could be set
   across multiple TE tunnels.  Grouping operation (such as maximum,
   mean) could be set at the time of configuration.  For example, if
   "maximum" grouping operation is used for delay at the VN level, the
   VN telemetry data is reported as the maximum of {delay_vn_member_1,
   delay_vn_member_2,..  delay_vn_member_N}. Thus, this telemetry
   aggregation mechanism allows the aggregation (or grouping) of a
   certain common set of telemetry values under a grouping operation.
   This can also be done at the VN-member level to suggest how the end-
   to-end (E2E) telemetry be inferred from the per domain tunnels
   created and monitored by PNCs.  The Figure 4 provides an example
   interaction.

     +------------------------------------------------------------+
     |                      Client                                |
     |                                                            |
     +------------------------------------------------------------+
     1.Client sets the      |   /|\   2. Orchestrator pushes:
     grouping op, and       |    |
     subscribes to the      |    |    VN level telemetry for
     VN level telemetry for |    |    - VN Utilized-bw-percentage
     Delay and              |    |       (Minimum across VN Members)
     Utilized-bw-pecentage  |    |    - VN Delay (Maximum across VN
                           \|/   |     Members)
      +------------------------------------------------------------+
      | Orchestrator                                               |
      |                                                            |
      +------------------------------------------------------------+

                 Figure 4: TE Telemetry Model Interactions

3.3.  VPN Service Performance Monitoring

   The YANG model in [I-D.ietf-opsawg-yang-vpn-service-pm] provides
   network performance monitoring (PM) and VPN service performance
   monitoring that can be used to monitor and manage network performance
   on the topology at higher layer or the service topology between VPN
   sites.  Thus the YANG models in this document could be used along
   side with ietf-network-vpn-pm to understand and correlate the
   performance monitoring at the VPN service and the underlying TE
   level.







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4.  Autonomic Scaling Intent Mechanism

   The scaling intent configuration mechanism allows the client to
   configure automatic scale-in and scale-out mechanisms on both the TE-
   tunnel and the VN level.  Various conditions can be set for auto-
   scaling based on the PM telemetry data.

   There are a number of parameters involved in the mechanism:

   *  scale-out-intent or scale-in-intent: whether to scale-out or
      scale-in.

   *  performance-type: performance metric type (e.g., one-way-delay,
      one-way-delay-min, one-way-delay-max, two-way-delay, two-way-
      delay-min, two-way-delay-max, utilized bandwidth, etc.)

   *  threshold-value: the threshold value for a certain performance-
      type that triggers scale-in or scale-out.

   *  scaling-operation-type: in case where scaling condition can be set
      with one or more performance types, then scaling-operation-type
      (AND, OR, MIN, MAX, etc.) is applied to these selected performance
      types and its threshold values.

   *  Threshold-time: the duration for which the criteria needs to hold
      true.

   *  Cooldown-time: the duration after a scaling action has been
      triggered, for which there will be no further operation.

   The tree in Figure 5 is a part of ietf-te-telemetry tree whose model
   is presented in full detail in Sections 6 & 7.



















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   module: ietf-te-telemetry
     augment /te:te/te:tunnels/te:tunnel:
       +--rw te-scaling-intent
       |  +--rw scale-in-intent
       |  |  +--rw threshold-time?      uint32
       |  |  +--rw cooldown-time?       uint32
       |  |  +--rw scaling-condition* [performance-type]
       |  |  |  +--rw performance-type           identityref
       |  |  |  +--rw threshold-value?           string
       |  |  |  +--rw scale-in-operation-type?
       |  |  |          scaling-criteria-operation
       |  |  +--rw scale-in-op?         identityref
       |  |  +--rw scale?               string
       |  +--rw scale-out-intent
       |     +--rw threshold-time?      uint32
       |     +--rw cooldown-time?       uint32
       |     +--rw scaling-condition* [performance-type]
       |     |  +--rw performance-type            identityref
       |     |  +--rw threshold-value?            string
       |     |  +--rw scale-out-operation-type?
       |     |          scaling-criteria-operation
       |     +--rw scale-out-op?        identityref
       |     +--rw scale?               string

                        Figure 5: The scaling intent

   Let's say the client wants to set the scaling out operation based on
   two performance-types (e.g., two-way-delay and utilized-bandwidth for
   a te-tunnel), it can be done as follows:

   *  Set Threshold-time: x (sec) (duration for which the criteria must
      hold true)

   *  Set Cooldown-time: y (sec) (the duration after a scaling action
      has been triggered, for which there will be no further operation)

   *  Set AND for the scale-out-operation-type

   In the scaling condition's list, the following two components can be
   set:

   List 1: Scaling Condition for Two-way-delay

   *  performance type: Two-way-delay

   *  threshold-value: z milli-seconds

   List 2: Scaling Condition for Utilized bandwidth



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   *  performance type: Utilized bandwidth

   *  threshold-value: w megabytes

5.  Notification

   This model does not define specific notifications.  To enable
   notifications, the mechanism defined in [RFC8641] and [RFC8640] can
   be used.  This mechanism currently allows the user to:

   *  Subscribe to notifications on a per client basis.

   *  Specify subtree filters or xpath filters so that only interested
      contents will be sent.

   *  Specify either periodic or on-demand notifications.

5.1.  YANG Push Subscription Examples

   [RFC8641] allows subscriber applications to request a continuous,
   customized stream of updates from a YANG datastore.

   The example in Figure 6 shows the way for a client to subscribe to
   the telemetry information for a particular tunnel (Tunnel1).  The
   telemetry parameter that the client is interested in is one-way-
   delay.

























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   <netconf:rpc netconf:message-id="101"
       xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
       <establish-subscription
          xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
          <filter netconf:type="subtree">
             <te xmlns="urn:ietf:params:xml:ns:yang:ietf-te">
                <tunnels>
                   <tunnel>
                     <name>Tunnel1</name>
                       <te-telemetry xmlns="urn:ietf:params:xml:ns:yang:
                                            ietf-te-telemetry">
                           <performance-metrics-one-way>
                              <one-way-delay/>
                           </performance-metrics-one-way>
                        </te-telemetry>
                     </tunnel>
                 </tunnels>
             </te>
          </filter>
          <period>500</period>
          <encoding>encode-xml</encoding>
       </establish-subscription>
    </netconf:rpc>

                  Figure 6: TE Tunnel Subscription Example

   The example in Figure 7 shows the way for a client to subscribe to
   the telemetry information for all VNs.  The telemetry parameter that
   the client is interested in is one-way-delay and one-way-utilized-
   bandwidth.





















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   <netconf:rpc netconf:message-id="101"
       xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
     <establish-subscription
        xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">
        <filter netconf:type="subtree">
           <virtual-network xmlns="urn:ietf:params:xml:ns:yang:ietf-vn">
              <vn>
                   <vn-id/>
                   <vn-telemetry xmlns="urn:ietf:params:xml:ns:yang:
                                         ietf-vn-telemetry">
                     <params>
                       <performance-metrics-one-way>
                         <one-way-delay/>
                         <one-way-utilized-bandwidth/>
                       </performance-metrics-one-way>
                     </params>
                   </vn-telemetry>
               </vn>
           </virtual-network>
        </filter>
        <period>500</period>
     </establish-subscription>
   </netconf:rpc>

                     Figure 7: VN Subscription Example

5.2.  Scaling Examples

   The example in Figure 8 shows the way to configure a TE tunnel with
   the scaling-out intent to re-optimize when the the scaling condition
   of two-way-delay crossing 100 milliseconds (100000 microseconds) for
   a threshold of 1 min (60000 milliseconds).



















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   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <target>
        <running/>
      </target>
      <config>
        <te xmlns="urn:ietf:params:xml:ns:yang:ietf-te">
            <tunnels>
               <tunnel>
                 <name>Tunnel1</name>
                   <te-scaling-intent
                     xmlns="urn:ietf:params:xml:ns:yang:
                            ietf-te-telemetry">
                       <scale-out-intent>
                          <threshold-time>
                           60000
                         </threshold-time>
                         <scaling-condition>
                           <performance-type>
                             two-way-delay
                           </performance-type>
                           <threshold-value>
                             100000
                           </threshold-value>
                           <scale-out-op>
                             re-optimize
                           </scale-out-op>
                         </scaling-condition>
                       </scale-out-intent>
                    </te-scaling-intent>
                 </tunnel>
             </tunnels>
        </te>
      </config>
   </edit-config>

                    Figure 8: TE Tunnel Scaling Example

   The example in Figure 9 shows the way to configure a VN with the
   scaling-in intent to reduce bandwidth when the the scaling condition
   of two-way-delay crossing 100 milliseconds (100000 microseconds) for
   a threshold of 1 min (60000 milliseconds).










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   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <target>
        <running/>
      </target>
      <config>
        <virtual-network xmlns="urn:ietf:params:xml:ns:yang:ietf-vn">
             <vn>
                 <vn-id>VN1</vn-id>
                   <vn-scaling-intent
                     xmlns="urn:ietf:params:xml:ns:yang:
                            ietf-vn-telemetry">
                       <scale-in-intent>
                         <threshold-time>60000</threshold-time>
                         <scaling-condition>
                           <performance-type>
                             utilized-percentage
                           </performance-type>
                           <threshold-value>
                             50
                           </threshold-value>
                           <scale-in-op>
                             scale-capacity-down
                           </scale-in-op>
                         </scaling-condition>
                       </scale-in-intent>
                 </vn-scaling-intent>
             </vn>
        </virtual-network>
      </config>
   </edit-config>

                        Figure 9: VN Scaling Example

   The example in Figure 10 shows the way to configure a grouping
   operation at the VN level to require that the VN level one-way-delay
   needs to be the reported as the max of the one-way-delay at the VN-
   member level, where as the utilized-percentage is the mean.














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   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <target>
        <running/>
      </target>
      <config>
        <virtual-network xmlns="urn:ietf:params:xml:ns:yang:ietf-vn">
             <vn>
                 <vn-id>VN1</vn-id>
                 <vn-telemetry
                   xmlns="urn:ietf:params:xml:ns:yang:
                          ietf-vn-telemetry">
                   <operation>
                     <performance-type>
                       one-way-delay
                     </performance-type>
                     <grouping-operation>
                       maximum
                     </grouping-operation>
                   </operation>
                   <operation>
                     <performance-type>
                       utilized-percentage
                     </performance-type>
                     <grouping-operation>
                       mean
                     </grouping-operation>
                   </operation>
                 </vn-telemetry>
             </vn>
        </virtual-network>
      </config>
   </edit-config>

                  Figure 10: VN Grouping Operation Example

6.  YANG Data Tree















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   module: ietf-te-telemetry
     augment /te:te/te:tunnels/te:tunnel:
       +--rw te-scaling-intent
       |  +--rw scale-in-intent
       |  |  +--rw threshold-time?      uint32
       |  |  +--rw cooldown-time?       uint32
       |  |  +--rw scaling-condition* [performance-type]
       |  |  |  +--rw performance-type           identityref
       |  |  |  +--rw threshold-value?           string
       |  |  |  +--rw scale-in-operation-type?
       |  |  |          scaling-criteria-operation
       |  |  +--rw scale-in-op?         identityref
       |  |  +--rw scale?               string
       |  +--rw scale-out-intent
       |     +--rw threshold-time?      uint32
       |     +--rw cooldown-time?       uint32
       |     +--rw scaling-condition* [performance-type]
       |     |  +--rw performance-type            identityref
       |     |  +--rw threshold-value?            string
       |     |  +--rw scale-out-operation-type?
       |     |          scaling-criteria-operation
       |     +--rw scale-out-op?        identityref
       |     +--rw scale?               string
       +--ro te-telemetry
          +--ro id?                            telemetry-id
          +--ro performance-metrics-one-way
          |  +--ro one-way-delay?                           uint32
          |  +--ro one-way-delay-normality?
          |  |       te-types:performance-metrics-normality
          |  +--ro one-way-residual-bandwidth?
          |  |       rt-types:bandwidth-ieee-float32
          |  +--ro one-way-residual-bandwidth-normality?
          |  |       te-types:performance-metrics-normality
          |  +--ro one-way-available-bandwidth?
          |  |       rt-types:bandwidth-ieee-float32
          |  +--ro one-way-available-bandwidth-normality?
          |  |       te-types:performance-metrics-normality
          |  +--ro one-way-utilized-bandwidth?
          |  |       rt-types:bandwidth-ieee-float32
          |  +--ro one-way-utilized-bandwidth-normality?
          |          te-types:performance-metrics-normality
          +--ro performance-metrics-two-way
             +--ro two-way-delay?             uint32
             +--ro two-way-delay-normality?
                     te-types:performance-metrics-normality

                Figure 11: ietf-te-telemetry YANG model tree




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   module: ietf-vn-telemetry
     augment /vn:virtual-network/vn:vn:
       +--rw vn-scaling-intent
       |  +--rw scale-in-intent
       |  |  +--rw threshold-time?      uint32
       |  |  +--rw cooldown-time?       uint32
       |  |  +--rw scaling-condition* [performance-type]
       |  |  |  +--rw performance-type           identityref
       |  |  |  +--rw threshold-value?           string
       |  |  |  +--rw scale-in-operation-type?
       |  |  |          scaling-criteria-operation
       |  |  +--rw scale-in-op?         identityref
       |  |  +--rw scale?               string
       |  +--rw scale-out-intent
       |     +--rw threshold-time?      uint32
       |     +--rw cooldown-time?       uint32
       |     +--rw scaling-condition* [performance-type]
       |     |  +--rw performance-type            identityref
       |     |  +--rw threshold-value?            string
       |     |  +--rw scale-out-operation-type?
       |     |          scaling-criteria-operation
       |     +--rw scale-out-op?        identityref
       |     +--rw scale?               string
       +--rw vn-telemetry
          +--ro params
          |  +--ro performance-metrics-one-way
          |  |  +--ro one-way-delay?                           uint32
          |  |  +--ro one-way-delay-normality?
          |  |  |       te-types:performance-metrics-normality
          |  |  +--ro one-way-residual-bandwidth?
          |  |  |       rt-types:bandwidth-ieee-float32
          |  |  +--ro one-way-residual-bandwidth-normality?
          |  |  |       te-types:performance-metrics-normality
          |  |  +--ro one-way-available-bandwidth?
          |  |  |       rt-types:bandwidth-ieee-float32
          |  |  +--ro one-way-available-bandwidth-normality?
          |  |  |       te-types:performance-metrics-normality
          |  |  +--ro one-way-utilized-bandwidth?
          |  |  |       rt-types:bandwidth-ieee-float32
          |  |  +--ro one-way-utilized-bandwidth-normality?
          |  |          te-types:performance-metrics-normality
          |  +--ro performance-metrics-two-way
          |     +--ro two-way-delay?             uint32
          |     +--ro two-way-delay-normality?
          |             te-types:performance-metrics-normality
          +--rw operation* [performance-type]
             +--rw performance-type      identityref
             +--rw grouping-operation?   identityref



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     augment /vn:virtual-network/vn:vn/vn:vn-member:
       +--rw vn-member-telemetry
          +--ro params
          |  +--ro performance-metrics-one-way
          |  |  +--ro one-way-delay?                           uint32
          |  |  +--ro one-way-delay-normality?
          |  |  |       te-types:performance-metrics-normality
          |  |  +--ro one-way-residual-bandwidth?
          |  |  |       rt-types:bandwidth-ieee-float32
          |  |  +--ro one-way-residual-bandwidth-normality?
          |  |  |       te-types:performance-metrics-normality
          |  |  +--ro one-way-available-bandwidth?
          |  |  |       rt-types:bandwidth-ieee-float32
          |  |  +--ro one-way-available-bandwidth-normality?
          |  |  |       te-types:performance-metrics-normality
          |  |  +--ro one-way-utilized-bandwidth?
          |  |  |       rt-types:bandwidth-ieee-float32
          |  |  +--ro one-way-utilized-bandwidth-normality?
          |  |          te-types:performance-metrics-normality
          |  +--ro performance-metrics-two-way
          |  |  +--ro two-way-delay?             uint32
          |  |  +--ro two-way-delay-normality?
          |  |          te-types:performance-metrics-normality
          |  +--ro te-grouped-params*
          |          -> /te:te/tunnels/tunnel/te-tel:te-telemetry/id
          +--rw operation* [performance-type]
             +--rw performance-type      identityref
             +--rw grouping-operation?   identityref

                Figure 12: ietf-vn-telemetry YANG model tree

7.  YANG Data Model

7.1.  ietf-te-telemetry model

   The YANG code is as follows:

   <CODE BEGINS> file "ietf-te-telemetry@2021-10-24.yang"
   module ietf-te-telemetry {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-te-telemetry";
     prefix te-tel;

     /* Import TE */

     import ietf-te {
       prefix te;
       reference



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         "I-D.ietf-teas-yang-te: A YANG Data Model for Traffic
          Engineering Tunnels and Interfaces";
     }

     /* Import TE Common types */

     import ietf-te-types {
       prefix te-types;
       reference
         "RFC 8776: Common YANG Data Types for Traffic Engineering";
     }

     organization
       "IETF Traffic Engineering Architecture and Signaling (TEAS)
        Working Group";
     contact
       "WG Web:  <https://tools.ietf.org/wg/teas/>
        WG List: <mailto:teas@ietf.org>
        Editor:  Young Lee <younglee.tx@gmail.com>
                 Dhruv Dhody <dhruv.ietf@gmail.com>";
     description
       "This module describes YANG data model for performance
        monitoring telemetry for te tunnels.
        Copyright (c) 2021 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 RFC XXXX; see the
        RFC itself for full legal notices.";

     /* Note: The RFC Editor will replace XXXX with the number
        assigned to the RFC once draft-ietf-teas-pm-telemetry-
        autonomics becomes an RFC.*/

     revision 2021-10-24 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: YANG models for VN/TE Performance Monitoring
          Telemetry and Scaling Intent Autonomics";
     }

     identity telemetry-param-type {



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       description
         "Base identity for telemetry param types";
     }

     identity one-way-delay {
       base telemetry-param-type;
       description
         "To specify average Delay in one (forward) direction.

          At the VN level, it is the max delay of the VN-members.

          The threshold-value for this type is interpreted as
          microseconds.";
       reference
         "RFC 7471: OSPF Traffic Engineering (TE) Metric Extensions.
          RFC 8570: IS-IS Traffic Engineering (TE) Metric Extensions.
          RFC 7823: Performance-Based Path Selection for Explicitly
          Routed Label Switched Paths (LSPs) Using TE Metric
          Extensions";
     }

     identity two-way-delay {
       base telemetry-param-type;
       description
         "To specify average Delay in both (forward and reverse)
          directions.

          At the VN level, it is the max delay of the VN-members.

          The threshold-value for this type is interpreted as
          microseconds.";
       reference
         "RFC 7471: OSPF Traffic Engineering (TE) Metric Extensions.
          RFC 8570: IS-IS Traffic Engineering (TE) Metric Extensions.
          RFC 7823: Performance-Based Path Selection for Explicitly
          Routed Label Switched Paths (LSPs) Using TE Metric
          Extensions";
     }

     identity one-way-delay-variation {
       base telemetry-param-type;
       description
         "To specify average Delay Variation in one (forward) direction.

          At the VN level, it is the max delay variation of the
          VN-members.

          The threshold-value for this type is interpreted as



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          microseconds.";
       reference
         "RFC 7471: OSPF Traffic Engineering (TE) Metric Extensions.
          RFC 8570: IS-IS Traffic Engineering (TE) Metric Extensions.
          RFC 7823: Performance-Based Path Selection for Explicitly
          Routed Label Switched Paths (LSPs) Using TE Metric
          Extensions";
     }

     identity two-way-delay-variation {
       base telemetry-param-type;
       description
         "To specify average Delay Variation in both (forward and
          reverse) directions.

          At the VN level, it is the max delay variation of the
          VN-members.


          The threshold-value for this type is interpreted as
          microseconds.";
       reference
         "RFC 7471: OSPF Traffic Engineering (TE) Metric Extensions.
          RFC 8570: IS-IS Traffic Engineering (TE) Metric Extensions.
          RFC 7823: Performance-Based Path Selection for Explicitly
          Routed Label Switched Paths (LSPs) Using TE Metric
          Extensions";
     }

     identity utilized-bandwidth {
       base telemetry-param-type;
       description
         "To specify utilized bandwidth over the specified source
          and destination.

          The threshold-value for this type is interpreted as
          bytes per second.";
       reference
         "RFC 7471: OSPF Traffic Engineering (TE) Metric Extensions.
          RFC 8570: IS-IS Traffic Engineering (TE) Metric Extensions.
          RFC 7823: Performance-Based Path Selection for Explicitly
          Routed Label Switched Paths (LSPs) Using TE Metric
          Extensions";
     }

     identity utilized-percentage {
       base telemetry-param-type;
       description



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         "To specify utilization percentage of the entity
          (e.g., tunnel, link, etc.)";
     }

     identity scale-op {
       description
         "Base identity for scaling operation";
     }

     identity scale-capacity-up {
       base scale-op;
       description
         "Scale up the bandwidth capacity";
     }

     identity scale-capacity-down {
       base scale-op;
       description
         "Scale down the bandwidth capacity";
     }

     /* Typedef */

     typedef telemetry-id {
       type string;
       description
         "Identifier for the telemetry data.";
     }

     typedef scaling-criteria-operation {
       type enumeration {
         enum AND {
           description
             "AND operation";
         }
         enum OR {
           description
             "OR operation";
         }
       }
       description
         "Operations to analize list of scaling criterias";
     }

     grouping scaling-duration {
       description
         "Base scaling criteria durations";
       leaf threshold-time {



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         type uint32;
         units "seconds";
         description
           "The duration for which the criteria must hold true";
       }
       leaf cooldown-time {
         type uint32;
         units "seconds";
         description
           "The duration after a scaling-in/scaling-out action has been
            triggered, for which there will be no further operation";
       }
     }

     grouping scaling-criteria {
       description
         "Grouping for scaling criteria";
       leaf performance-type {
         type identityref {
           base telemetry-param-type;
         }
         description
           "Reference to the tunnel level telemetry type";
       }
       leaf threshold-value {
         type string;
         description
           "Scaling threshold for the telemetry parameter type.";
       }
     }

     grouping scaling-in-intent {
       description
         "Basic scaling in intent";
       uses scaling-duration;
       list scaling-condition {
         key "performance-type";
         description
           "Scaling conditions";
         uses scaling-criteria;
         leaf scale-in-operation-type {
           type scaling-criteria-operation;
           default "AND";
           description
             "Operation to be applied to check between scaling criterias
              to check if the scale in threshold condition has been met.
              Defaults to AND";
         }



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       }
       leaf scale-in-op {
         type identityref {
           base scale-op;
         }
         default "scale-capacity-down";
         description
           "The scaling operation to be performed when scaling condition
            is met";
       }
       leaf scale {
         type string;
         description
           "Additional scaling-by information to be interpritted as per
            the scale-in-op.";
       }
     }

     grouping scaling-out-intent {
       description
         "Basic scaling out intent";
       uses scaling-duration;
       list scaling-condition {
         key "performance-type";
         description
           "Scaling conditions";
         uses scaling-criteria;
         leaf scale-out-operation-type {
           type scaling-criteria-operation;
           default "OR";
           description
             "Operation to be applied to check between scaling criterias
              to check if the scale out threshold condition has been met.
              Defauls to OR";
         }
       }
       leaf scale-out-op {
         type identityref {
           base scale-op;
         }
         default "scale-capacity-up";
         description
           "The scaling operation to be performed when scaling condition
            is met";
       }
       leaf scale {
         type string;
         description



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           "Additional scaling-by information to be interpritted as per
            the scale-out-op.";
       }
     }

     augment "/te:te/te:tunnels/te:tunnel" {
       description
         "Augmentation parameters for config scaling-criteria TE
          tunnel topologies. Scale in/out criteria might be used
          for network autonomics in order the controller to react
          to a certain set of monitored params.";
       container te-scaling-intent {
         description
           "The scaling intent";
         container scale-in-intent {
           description
             "scale-in";
           uses scaling-in-intent;
         }
         container scale-out-intent {
           description
             "scale-out";
           uses scaling-out-intent;
         }
       }
       container te-telemetry {
         config false;
         description
           "Telemetry Data";
         leaf id {
           type telemetry-id;
           description
             "ID of telemetry data used for easy reference";
         }
         uses te-types:performance-metrics-attributes;
       }
     }
   }
   <CODE ENDS>

7.2.  ietf-vn-telemetry model

   The YANG code is as follows:








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   <CODE BEGINS> file "ietf-vn-telemetry@2021-10-24.yang"
   module ietf-vn-telemetry {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-vn-telemetry";
     prefix vn-tel;

     /* Import VN */

     import ietf-vn {
       prefix vn;
       reference
         "I-D.ietf-teas-actn-vn-yang: A YANG Data Model for VN
          Operation";
     }

     /* Import TE */

     import ietf-te {
       prefix te;
       reference
         "I-D.ietf-teas-yang-te: A YANG Data Model for Traffic
          Engineering Tunnels and Interfaces";
     }

     /* Import TE Common types */

     import ietf-te-types {
       prefix te-types;
       reference
         "RFC 8776: Common YANG Data Types for Traffic Engineering";
     }

     /* Import TE Telemetry */

     import ietf-te-telemetry {
       prefix te-tel;
       reference
         "RFC XXXX: YANG models for VN/TE Performance Monitoring
          Telemetry and Scaling Intent Autonomics";
     }

     /* Note: The RFC Editor will replace XXXX with the number
        assigned to this draft.*/

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



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       "WG Web:  <https://tools.ietf.org/wg/teas/>
        WG List: <mailto:teas@ietf.org>
        Editor:  Young Lee <younglee.tx@gmail.com>
                 Dhruv Dhody <dhruv.ietf@gmail.com>";
     description
       "This module describes YANG data models for performance
        monitoring telemetry for Virtual Network (VN).

        Copyright (c) 2021 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 RFC XXXX; see the
        RFC itself for full legal notices.";

     /* Note: The RFC Editor will replace XXXX with the number
        assigned to the RFC once draft-lee-teas-pm-telemetry-
        autonomics becomes an RFC.*/

     revision 2021-10-24 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: YANG models for VN/TE Performance Monitoring
          Telemetry and Scaling Intent Autonomics";
     }

     identity grouping-op {
       description
         "Base identity for grouping-operation";
     }

     identity minimum {
       base grouping-op;
       description
         "Select the minimum of the monitored parameters";
     }

     identity maximum {
       base grouping-op;
       description
         "The maximum of the monitored parameters";



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     }

     identity mean {
       base grouping-op;
       description
         "The mean of the monitored parameters";
     }

     identity standard-deviation {
       base grouping-op;
       description
         "The standard deviation of the monitored parameters";
     }

     identity sum {
       base grouping-op;
       description
         "The sum of the monitored parameters";
     }

     identity and {
       base grouping-op;
       description
         "Logical AND operation";
     }

     identity or {
       base grouping-op;
       description
         "Logical OR operation";
     }

     grouping grouping-operation {
       list operation {
         key "performance-type";
         leaf performance-type {
           type identityref {
             base te-tel:telemetry-param-type;
           }
           description
             "Reference to the tunnel level telemetry type";
         }
         leaf grouping-operation {
           type identityref {
             base grouping-op;
           }
           description
             "describes the operation to apply to the te-grouped-params";



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         }
         description
           "Grouping operation for each performance-type";
       }
       description
         "Grouping operation for each performance-type";
     }

     augment "/vn:virtual-network/vn:vn" {
       description
         "Augmentation parameters for state TE VN topologies.";
       container vn-scaling-intent {
         description
           "scaling intent";
         container scale-in-intent {
           description
             "VN scale-in";
           uses te-tel:scaling-in-intent;
         }
         container scale-out-intent {
           description
             "VN scale-out";
           uses te-tel:scaling-out-intent;
         }
       }
       container vn-telemetry {
         description
           "VN telemetry params";
         container params {
           config false;
           description
             "Read-only telemetry parameters";
           uses te-types:performance-metrics-attributes;
         }
         uses grouping-operation;
       }
     }

     augment "/vn:virtual-network/vn:vn/vn:vn-member" {
       description
         "Augmentation parameters for state TE vn member topologies.";
       container vn-member-telemetry {
         description
           "VN member telemetry params";
         container params {
           config false;
           description
             "Read-only telemetry parameters";



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           uses te-types:performance-metrics-attributes;
           leaf-list te-grouped-params {
             type leafref {
               path
                 "/te:te/te:tunnels/te:tunnel/" +
                 "te-tel:te-telemetry/te-tel:id";
             }
             description
               "A list of underlying TE parameters that form the
                VN-member";
           }
         }
         uses grouping-operation;
       }
     }
   }
   <CODE ENDS>

8.  Security Considerations

   The YANG modules specified in this document defines a schema for data
   that 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
   [RFC8446].

   The Network Configuration Access Control Model (NACM) [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.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees with the write
   operation that can be exploited to impact the network monitoring.  An
   incorrect condition could cause frequent scaling operation to be
   executed causing harm to the network:

   *  /te:te/te:tunnels/te:tunnel/te-scaling-intent/scale-in-intent

   *  /te:te/te:tunnels/te:tunnel/te-scaling-intent/scale-out-intent

   *  /vn:virtual-network/vn:vn/vn-scaling-intent/scale-in-intent



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   *  /vn:virtual-network/vn:vn/vn-scaling-intent/scale-out-intent

   Further, following are the subtrees with the write operation that can
   be exploited by setting an incorrect grouping operation for the VN
   operation impacting the network monitoring:

   *  /vn:virtual-network/vn:vn/vn-telemetry/operation

   *  /vn:virtual-network/vn:vn/vn:vn-member/vn-member-telemetry/
      operation

   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.  These are the subtrees with the
   read operations that can be exploited to learn real-time (and
   sensitive) telemetry information about the TE tunnels and VN:

   *  /te:te/te:tunnels/te:tunnel/te-telemetry

   *  /vn:virtual-network/vn:vn/vn-telemetry

   *  /vn:virtual-network/vn:vn/vn:vn-member/vn-member-telemetry

9.  IANA Considerations

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

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

   --------------------------------------------------------------------
   URI: urn:ietf:params:xml:ns:yang:ietf-vn-telemetry
   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
   registry.

   Names registry [RFC7950]:






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   --------------------------------------------------------------------
   name:         ietf-te-telemetry
   namespace:    urn:ietf:params:xml:ns:yang:ietf-te-telemetry
   prefix:       te-tel
   reference:    RFC XXXX
   --------------------------------------------------------------------

   --------------------------------------------------------------------
   name:         ietf-vn-telemetry
   namespace:    urn:ietf:params:xml:ns:yang:ietf-vn-telemetry
   prefix:       vn-tel
   reference:    RFC XXXX
   --------------------------------------------------------------------

10.  Acknowledgements

   We thank Adrian Farrel, Rakesh Gandhi, Tarek Saad, Igor Bryskin,
   Kenichi Ogaki, and Greg Mirsky for useful discussions and their
   suggestions for this work.

11.  References

11.1.  Normative References

   [I-D.ietf-teas-actn-vn-yang]
              Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., and B. Y.
              Yoon, "A YANG Data Model for VN Operation", Work in
              Progress, Internet-Draft, draft-ietf-teas-actn-vn-yang-13,
              23 October 2021, <https://datatracker.ietf.org/doc/html/
              draft-ietf-teas-actn-vn-yang-13>.

   [I-D.ietf-teas-yang-te]
              Saad, T., Gandhi, R., Liu, X., Beeram, V. P., Bryskin, I.,
              and O. G. D. Dios, "A YANG Data Model for Traffic
              Engineering Tunnels, Label Switched Paths and Interfaces",
              Work in Progress, Internet-Draft, draft-ietf-teas-yang-te-
              27, 8 July 2021, <https://datatracker.ietf.org/doc/html/
              draft-ietf-teas-yang-te-27>.

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

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




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   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [RFC7926]  Farrel, A., Ed., Drake, J., Bitar, N., Swallow, G.,
              Ceccarelli, D., and X. Zhang, "Problem Statement and
              Architecture for Information Exchange between
              Interconnected Traffic-Engineered Networks", BCP 206,
              RFC 7926, DOI 10.17487/RFC7926, July 2016,
              <https://www.rfc-editor.org/info/rfc7926>.

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

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8233]  Dhody, D., Wu, Q., Manral, V., Ali, Z., and K. Kumaki,
              "Extensions to the Path Computation Element Communication
              Protocol (PCEP) to Compute Service-Aware Label Switched
              Paths (LSPs)", RFC 8233, DOI 10.17487/RFC8233, September
              2017, <https://www.rfc-editor.org/info/rfc8233>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8640]  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
              E., and A. Tripathy, "Dynamic Subscription to YANG Events
              and Datastores over NETCONF", RFC 8640,
              DOI 10.17487/RFC8640, September 2019,
              <https://www.rfc-editor.org/info/rfc8640>.



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   [RFC8641]  Clemm, A. and E. Voit, "Subscription to YANG Notifications
              for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
              September 2019, <https://www.rfc-editor.org/info/rfc8641>.

   [RFC8776]  Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
              "Common YANG Data Types for Traffic Engineering",
              RFC 8776, DOI 10.17487/RFC8776, June 2020,
              <https://www.rfc-editor.org/info/rfc8776>.

11.2.  Informative References

   [I-D.ietf-opsawg-yang-vpn-service-pm]
              Wu, B., Wu, Q., Boucadair, M., Dios, O. G. D., Wen, B.,
              Liu, C., and H. Xu, "A YANG Model for Network and VPN
              Service Performance Monitoring", Work in Progress,
              Internet-Draft, draft-ietf-opsawg-yang-vpn-service-pm-01,
              6 July 2021, <https://datatracker.ietf.org/doc/html/draft-
              ietf-opsawg-yang-vpn-service-pm-01>.

   [RFC7471]  Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
              Previdi, "OSPF Traffic Engineering (TE) Metric
              Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015,
              <https://www.rfc-editor.org/info/rfc7471>.

   [RFC7823]  Atlas, A., Drake, J., Giacalone, S., and S. Previdi,
              "Performance-Based Path Selection for Explicitly Routed
              Label Switched Paths (LSPs) Using TE Metric Extensions",
              RFC 7823, DOI 10.17487/RFC7823, May 2016,
              <https://www.rfc-editor.org/info/rfc7823>.

   [RFC8309]  Wu, Q., Liu, W., and A. Farrel, "Service Models
              Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
              <https://www.rfc-editor.org/info/rfc8309>.

   [RFC8453]  Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for
              Abstraction and Control of TE Networks (ACTN)", RFC 8453,
              DOI 10.17487/RFC8453, August 2018,
              <https://www.rfc-editor.org/info/rfc8453>.

   [RFC8570]  Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
              D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
              Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March
              2019, <https://www.rfc-editor.org/info/rfc8570>.

Authors' Addresses






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Internet-Draft            VN/TE Perf Monitoring             October 2021


   Young Lee (editor)
   Samsung Electronics

   Email: younglee.tx@gmail.com


   Dhruv Dhody (editor)
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore 560066
   Karnataka
   India

   Email: dhruv.ietf@gmail.com


   Satish Karunanithi
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore 560066
   Karnataka
   India

   Email: satish.karunanithi@gmail.com


   Ricard Vilalta
   CTTC
   Centre Tecnologic de Telecomunicacions de Catalunya (CTTC/CERCA)
   Barcelona
   Spain

   Email: ricard.vilalta@cttc.es


   Daniel King
   Lancaster University

   Email: d.king@lancaster.ac.uk


   Daniele Ceccarelli
   Ericsson
   Torshamnsgatan,48
   Stockholm, Sweden

   Email: daniele.ceccarelli@ericsson.com




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