Internet Research Task Force                                 K. Yao, Ed.
Internet-Draft                                              D. Chen, Ed.
Intended status: Informational                              China Mobile
Expires: 9 January 2025                                    J. Jeong, Ed.
                                                 Sungkyunkwan University
                                                                   Q. Wu
                                                                  Huawei
                                                                 C. Yang
                                                       Xidian University
                                                            L. Contreras
                                                              Telefonica
                                                             8 July 2024


          Use Cases and Practices for Intent-Based Networking
                     draft-kdj-nmrg-ibn-usecases-01

Abstract

   This document proposes several use cases of Intent-Based Networking
   (IBN) and the methodologies to differ each use case by following the
   lifecycle of a real IBN system.  It includes the initial system
   awareness and data collection for the IBN system and the construction
   of the IBN system, which consists of intent translation, deployment,
   verification, evaluation, and optimization.  Practice learnings are
   also summarized to instruct the construction of next generation
   network management systems with the integration of IBN techniques.

Requirements Language

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

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at 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."



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   This Internet-Draft will expire on 9 January 2025.

Copyright Notice

   Copyright (c) 2024 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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Methodologies for Building IBN Systems  . . . . . . . . . . .   3
     2.1.  System Awareness and Data Collection  . . . . . . . . . .   3
     2.2.  Construction of IBN Systems . . . . . . . . . . . . . . .   5
   3.  IBN Use Cases . . . . . . . . . . . . . . . . . . . . . . . .  10
     3.1.  IBN for Routing and Path Selection  . . . . . . . . . . .  10
       3.1.1.  IBN for Service Function Chaining . . . . . . . . . .  10
       3.1.2.  IBN for SRv6 Networks . . . . . . . . . . . . . . . .  12
     3.2.  IBN for SLA Guarantee . . . . . . . . . . . . . . . . . .  14
       3.2.1.  Clustered Alternate-Marking Methodology . . . . . . .  15
     3.3.  IBN for Cloud-Based Security Service Management . . . . .  17
     3.4.  IBN for IoT Device Management . . . . . . . . . . . . . .  18
     3.5.  IBN for Sofware-Defined Vehicle Management  . . . . . . .  19
     3.6.  IBN for Interconnection . . . . . . . . . . . . . . . . .  22
     3.7.  IBN for IETF Network Slices . . . . . . . . . . . . . . .  24
   4.  Practice Learnings  . . . . . . . . . . . . . . . . . . . . .  26
     4.1.  Difficulties and Challenges . . . . . . . . . . . . . . .  26
     4.2.  Future Research Directions  . . . . . . . . . . . . . . .  27
   5.  Other Considerations  . . . . . . . . . . . . . . . . . . . .  28
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  28
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  28
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  28
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  28
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  29
   Appendix A.  Changes from draft-kdj-nmrg-ibn-usecases-00  . . . .  31
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  31
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  31
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  32





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1.  Introduction

   [RFC9315] gives the concepts and definition of Intent-Based
   Networking (IBN), and [RFC9316] proposes a comprehensive taxonomy of
   the intent classifications.  Although the intent life cycle has been
   defined, including all the core functional components like intent
   ingestion, intent translation, policy generation, and intent
   assurance.  However, there is still a gap between defining these
   high-level functionality and building realistic IBN systems.  This
   document proposes several IBN use cases and summarizes the
   methodologies and practice learnings when building these IBN systems.
   Main objectives of this document is to instruct future research
   directions of IBN and other related network management technologies.

2.  Methodologies for Building IBN Systems

   This section summarizes the methodologies to build an IBN system.
   These methodologies refer to the modelling of IBN life cycle and
   those high-level core functional components, as well as the specific
   solutions to implement those components.  The methodologies are
   essential to build a real IBN system, beyond the definition in
   [RFC9315].  The methodologies to an IBN system are composed of
   several important parts, including the system awareness and data
   collection, construction of IBN systems, integration and deployment,
   evaluation, optimization, and reconfiguration of intents and
   policies.

2.1.  System Awareness and Data Collection

   System awareness requires the collection of various network status
   indicators, like network traffic and resources.  Building a valuable
   dataset is essential for IBN systems.  A comprehensive data
   collection depends on suitable methods and tools, appropriate
   sampling metrics, and reasonable granularity for data collection.

   1.  Methods and Tools

       *  There are many existing ways to collect network data which can
          be primarily classified into two types, active measurement and
          passive measurement.  Active measurement like In-band network
          telemetry (INT) can grab networking information by inserting
          timestamps into programmable field of on-path packets.
          Passive measurement, on the other hand, uses some tools like
          Tcpdump or wireshark to collect data at specific targets, like
          endpoint servers.  IBN systems need both of the ways to
          collect data, depending on what scenarios they might be
          applied to.




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   2.  Metrics

       *  Metrics include traffic-related and network-related
          information.  Traffic-related metrics are performance
          indicators, such as latency, throughput, and traffic
          congestion signals.  Network-related information includes
          network device information, like the number and health status
          of ports, and network topology information, such as link
          connectivity and structures.  To meet a specific user
          intention, such as load balancing and congestion elimination
          on the entire network, IBN systems need to collect and process
          traffic and device related information.

   3.  Granularity

       *  Network Traffic.  Network traffic is usually collected in
          various forms, such as per-packet and per-flow, and these are
          two most typical types of data collection.  Per-packet means
          that each packet is tracked, which is very accurate, but it
          also means greater monitoring overhead and state maintenance
          overhead.  In contrast, per-flow tracking does not need to
          maintain too much state, and it generally uses five-tuples to
          identify each flow, which often brings good observation
          results.  Other collection methods are like per-cell and per-
          flowlet.  Per-cell is to track each cell unit whose length
          remains unchangeable, which is more friendly to system
          management and control.  This method is often applied to
          Artificial Intelligent (AI) data center network monitoring.
          The per-flowlet mode cuts a flow into several small flows at a
          certain interval, which is more suitable for implementing
          refined load balancing scenarios.  The IBN system should
          select an appropriate traffic collection granularity.

       *  Time granularity.  Time granularity means that the data
          acquisition needs to adopt the appropriate time interval for
          data sampling.  In the extreme case, data is collected without
          interruption.  For example, the status information of each
          data packet is reported to the monitoring module without
          interruption.  This collection method often brings too much
          redundant information, which leads to a lot of storage and
          computing overhead to the system.  However, the method of
          sampling without interruption or at a very low time interval
          can better observe micro-bursts of the networking system.  A
          micro-burst occurs when a large amount of burst data is
          received in milliseconds.  For some black-box network systems
          and some high-concurrency network systems, it is necessary to
          sacrifice a certain amount of storage and computing costs to
          collect data in a finer granularity time slot, so as to make



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          better trade-offs between system overhead and data acquisition
          accuracy.  By analyzing the historical behavior of IBN
          systems, a reasonable time interval can be selected for data
          acquisition.

       *  Spatial granularity.  Spatial granularity indicates that it is
          necessary to select an appropriate physical scope of a network
          for data collection.  In some cases, the information
          collection method based on the whole network and the whole
          domains may not be suitable for all situations, and sometimes
          the results obtained from the processing and analysis of the
          collected data may not be accurate (e.g., RTT-based congestion
          control in data center networking) or incur too much overhead
          (e.g., hop-by-hop performance monitoring over the Internet).
          The best way is to match the most appropriate spatial
          granularity for user intents.  For example, in wide-area data
          transmission, users need to select an optimal path.  In this
          case, sampling is not required for all paths from a source to
          a destination.  Only partial sampling is required for certain
          path segments which share endpoints, to ensure the correctness
          of decision makings on path setup in a scenario of multi-path
          data transmission.

2.2.  Construction of IBN Systems

   In the construction of an IBN system, intent translation module,
   policy generation and mapping module, and intent verification module
   play an important role.  The different construction methods and
   different construction tools used in these modules may affect the
   advantages of realizing the intention.  For different modules, we
   summarize the methods and tools that have been used and may be used.

   1.  Intent Translation

       *  Translating and refining intents require the system to explore
          and exploit the semantic relationships of different service
          intents, and thus it is necessary to build a general model to
          extract these key semantic information from the service
          intents in different representation forms.  In the intent
          translation module, several possible intent expression and
          translation methods are as follows:

          -  A limited range of templates are preset in advance, and
             users can only express corresponding intentions by filling
             in or selecting templates.  The advantage of this method is
             that the requirements for users and translation are very
             low, and all users can use it without learning.  The
             disadvantage is that there are many restrictions, which can



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             only be achieved through the preset template, but the
             preset template is limited, and cannot really meet the
             flexible and diverse needs of users;

          -  Using natural language processing (NLP), such as BERT, for
             intent translation is another possible approach.  First,
             natural language processing is used to convert a user
             intent into a text intent, and then the key parameters of
             text intent are extracted to form the corresponding intent
             expression.  The advantage of this method is high
             flexibility, users can directly express their intentions in
             a natural language according to their own needs, without
             being limited by templates.  The disadvantage is that it is
             difficult to implement and has high requirements for the
             intent translation module, which needs to be able to
             accurately identify the real intent of users, and different
             intents expression paradigms will affect the generation of
             subsequent policies, so it is necessary to formalize
             normative intent expression grammars.

          -  On the basis of the above natural language-based approach,
             with the development of AI technologies such as deep
             learning in the field of text processing, key information
             in sentences can be extracted by AI model detection.
             Therefore, based on different AI models, the translation
             method of category detection and key information extraction
             of intent representation statements is another approach to
             intent translation.  The advantage of this method is that
             the expression of the user's intention is more flexible,
             and the real intention of the user can be mined to a
             certain extent.  The disadvantage is in the deployment
             cost.  Selecting an appropriate AI model to complete the
             model training is costly.

          -  In addition, there are some pre-set expression languages
             for IBN networks, such as Nile, and NEMO.  In the design of
             these language expressions, most of them consider the
             flexibility of expression, which can be extended and
             adjusted according to the intention scenario of the
             business under consideration.  However, these language
             designs have some disadvantages (e.g., the capability of
             intent expression).  Most of the users are network
             practitioners, requiring users to have certain network
             knowledge background.

   2.  Policy Generation and Mapping





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       *  In the intent-based network, the generation of the
          corresponding network policy needs to consider both the input
          intent and the network state, that is, the policy needs to
          satisfy the user's intent and ensure that the network can be
          executed to satisfy the requested intent.  The policy
          generation module can be implemented by setting up a
          repository of “intent” - “policy”, and new mapping
          relationship should be stored and updated as knowledge
          according to various intents and dynamic network state
          telemetry.  Similar to different ways of expressing an intent,
          there are different approaches for policy generation and
          mapping.

          -  As opposed to the default template-based representation in
             the intent representation module, the simplest approach to
             policy generation is based on a default template or rule-
             based provisioning.  After the user completes the
             corresponding intention expression through the graphical
             interface (e.g., a web-based graphical user
             interface(GUI)), the user can select the corresponding
             policy according to the preset template in the policy
             generation and matching a module or associate the
             corresponding rules in the constructed rule-based policy
             generator.  Similar to the above analysis, this approach
             has the advantage of being very simple to implement, but
             the disadvantage is that it is too restrictive and only a
             limited number of preset strategies can be selected.

          -  The second common method of policy generation and mapping
             is inference-based generation, such as reasoning based on
             keywords or keywords in an intention expression,
             associating keywords with policies, and using circular
             reasoning to generate policies.  This method is more
             flexible than the template class description method, but
             the precision of policy generation is more related to the
             keyword extraction, and there is some uncertainty.  In
             addition, there are policy generation methods based on
             network service description, which are widely used in
             service function chaining (SFC), network slicing or network
             functions virtualization (NFV).  In essence, this approach
             can also be seen as inference-based strategy generation

          -  In addition to the above methods, AI technology-based
             strategy generation methods have also emerged in recent
             years, such as machine learning technology, which selects
             corresponding strategies through model training according
             to keywords extracted from an intention expression.  With
             the development of AI technology, in addition to selecting



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             preset strategies, for example, based on deep reinforcement
             learning, reasonable reward functions are set to generate
             strategies that consider user intentions and network
             status.

   3.  Intent Deployment

       *  Intent Deployment is to deploy the policy translated from an
          intent into a target network and let the configurations or
          commands for the policy operate in the network.

          -  The intent translator delivers a policy with detailed
             configurations or commands to an intent renderer which
             deploys the policy into target network entities (e.g.,
             switch, router, firewall, web filter, and DDoS-attack
             mitigator).

          -  The intent renderer delivers the policy to the target
             network entities with a policy delivery protocol such as
             NETCONF [RFC6241], RESTCONF [RFC8040], or REST API [REST].

   4.  Intent Verification

       *  Intent verification includes intent conflict detection and
          checking whether intents meet a specific user's requirements
          or not.

          -  The intent conflict detection includes two types: the
             conflicts between different intents themselves and the
             conflicts between policies and network states of the target
             network to perform the requested intent.  The conflict of
             intentions may be due to the conflict between the network
             states that different users want to obtain.  The simplest
             example is that both users A and B request to increase the
             bandwidth of 10Gbps, but the network bandwidth of the
             shared network for users A and B is less than 20Gbps.  This
             conflict caused by different user requirements can be
             resolved by checking whether the intents can be deployed in
             practice, that is, you can choose to execute only the
             intents that can be executed according to the preset rules,
             and reject other intents.  If the generated policy
             conflicts with the network state, the network state must be
             detected when the generated policy is generated to ensure
             that the generated policy can be executed by the target
             network.  If the generated policy cannot be executed, the
             policy needs to be re-generated.  Otherwise, the policy
             generation of the intent should be reported of a failure to
             the intent user.



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          -  In terms of whether the user's intent is satisfied or not,
             the first way is to feedback the result to the user, and
             the user judges whether it is satisfied.  This way the
             execution result can be presented through a graphical
             interface.  The second way is to use AI methods such as
             deep reinforcement learning to determine whether the
             results meet the needs.

   5.  Evaluation

       *  Evaluation is to judge whether an intent is satisfied by
          network entities (e.g., switch, router, firewall, web filter,
          and DDoS-attack mitigator) or not.  The intent is translated
          into a policy with detailed configurations or commands by an
          intent translator.  The policy may have goals in terms of
          performance (e.g., throughput and delay) and services (e.g.,
          firewall, web filter, and DDoS-attak mitigator).

          -  An evaluation entity (e.g., analyzer) needs to collect
             monitoring data from the network entities and check whether
             the required goals for each intent are met with specific
             metrics from the monitoring data or not.  This checking can
             be performed by Artificial Intelligence (AI) and Machine
             Learning (ML) algorithms.

          -  Evaluation results need to be delivered to an optimizer
             which can augment the existing policy or generate a new
             policy.

   6.  Optimization

       *  Optimization is to augment the existing policy or generate a
          new policy to meet the goals of the requested intent.  With
          the evaluation results, an optimization entity (e.g.,
          optimizer) performs optimization for each registered intent.

          -  There are two kinds of optimization, such as Quality of
             Service (QoS) and Service Provisioning.  First, the
             optimizer for QoS deals with the improvement of performance
             metrics (e.g., throughput and delay).  Second, the
             optimizer for service provisioning handles the service
             requirements (e.g., firewall filtering, web filtering, and
             DDoS-attack mitigation).  For each optimization, the
             optimizer augments the existing policy or generates a new
             policy.  It delivers the policy to the intent renderer so
             that the rendered can enforce the augmented or generated
             policy into the target network entities.




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          -  Thus, the steps from Intent Deployment to Optimization
             construct a closed-loop control to guarantee the goals of
             the requested intent in a target network.

3.  IBN Use Cases

   In this Section, we will describe several scenarios where IBN can be
   applied.  These use cases can reflect the aforementioned
   methodologies of IBN systems from different perspectives.

3.1.  IBN for Routing and Path Selection

   IBN can be applied in building network path and generating routing
   policies according to network administrators' requests.

3.1.1.  IBN for Service Function Chaining

   We use the intent-based dynamic SFC as an example to solve the
   network management challenges (e.g., cross-domain orchestration and
   service functions are tightly coupled with the underlying equipment).
   At the same time, we developed an Openstack-based IBNM platform.  The
   system architecture is shown as Fig 1, which includes the application
   layer, the intent-enabled layer and the infrastructure layer.  The
   application layer collects intents from various users and
   applications, and provides a number of programmable network
   management services.  The intent-enabled layer consists of the intent
   translation module, intelligent policy mapping module, and intent
   guarantee module, whose functions are to build a bridge between the
   application layer and the infrastructure layer.  Heterogeneous
   physical devices are deployed in the infrastructure layer.  This
   layer can execute management instructions from the intent-enabled
   layer and upload underlying network situation information to the
   intent-enabled layer.  Information interaction between different
   layers is done through different interfaces, such as the northbound
   and southbound interfaces.
















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     +----------------------------------------+
     |          Application   Layer           |
     +-------------+---------^----------------+
   Intent Ingestion|         | Northbound Interface
     +-------------+---------v----------------+
     |             |      Intent-enabled Layer|
     | +-----------+-------+  +-------------+ |
     | |           |       |  |             | |
     | |  +--------v----+  |  |             | |
     | |  | Translation |  |  |             | |
     | |  +-------------+  |  |             | |
     | |                   |  | Intelligent | |
     | |  +-------------+  |  |             | |
     | |  | Verification|  |  |  Guarantee  | |
     | |  +-------------+  |  |             | |
     | |Intent Translation |  |    Module   | |
     | |      Module       |  |             | |
     | +-------------------+  |             | |
     |                        |             | |
     | +-------------------+  |             | |
     | |Intelligent Policy |  |             | |
     | |  Mapping Module   |  |             | |
     | +-------------------+  +-------------+ |
     |                                        |
     +--------------------^-------------------+
                          |  Southbound Interface
     +--------------------v-------------------+
     |         Infrastructure Layer           |
     +----------------------------------------+

                     Figure 1: The Architecture of IBNM

   The system demonstration implements the whole process from intent
   input to intent translation to intent policy generation to intent
   deployment, and the details are as follows.

   The user input cross-domain link-building requests (intent) in
   natural language at the web-page: Transfer a common-level video
   service from user A in Beijing to user B in Nanjing while
   constraining the execution time of the intent.  The intent
   translation module outputs a conflict-free translation result, which
   indicates that the external input and the translation platform have
   been communicated.  The translation results are intent tuples, which
   are displayed on the front-end interface in the form of name-value
   pairs.  After the intent translation module, the translation results
   will be converted to JavaScript Object Notation (JSON) and
   transmitted to the intelligent policy mapping module.  The
   intelligent policy mapping module divides the JSON request into an



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   SFC: service function 1 (network address translation) service
   function 2 (firewall), and constructs the SFC request (name,
   tenant_id, description, service requirements, etc.).  Then query
   whether there is an atomic policy combination that satisfies the
   current intent requirements in the policy repository.  Following
   that, SFC is constructed based on the SFC interface, which is
   extended by Neutron.  OpenStack schedules network resources,
   constructs sub-nets and ports, and generates two-dimensional space
   topology.  Meanwhile, during the SFC construction process, the intent
   guarantee module monitors and manages network resource utilization as
   well as network failures in real time.  Overall, IBNM achieves the
   decoupling of service application and network, and cross-domain
   network orchestration, while reducing the complexity of network
   management.

3.1.2.  IBN for SRv6 Networks

   For the automation of configuration and monitoring of Segment Routing
   version six (SRv6) routers, an IBN-based secure network management is
   proposed by [I-D.park-nmrg-ibn-network-management-srv6].  The
   proposed Intent-Based Network Management (IBNM) framework consists of
   system components and interfaces, as shown in Figure 2.  This
   framework builds on the framework for Interface to Network Security
   Functions (I2NSF) [RFC8329].



























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      +-------------+                   +-----------------------------+
      |  IBN User   |                   | Global Distributed Database |
      +-------------+                   +-----------------------------+
             ^                                                     ^
             | Consumer-Facing                    Software Update  |
             | Interface                            Interface (Up) |
             v                                                     v
   +-------------------+     Registration     +-----------------------+
   |   IBN Controller  |<-------------------->|  Vendor's Mgmt System |
   +-------------------+      Interface       +-----------------------+
             ^      ^                                            ^
             |      |                  Software Update Interface |
             |      |                                     (Down) |
             |      |   Analytics Interface   +----------------+ |
             |      +------------------------>|  IBN Analyzer  | |
             |                                +----------------+ |
             | NSF-Facing Interface                   ^          |
             |                                        |          |
             |                  +---------------------+          |
             |                  |  Monitoring Interface          |
             |                  |                                |
   +---------+------------------+--------------------------------+----+
   |         v                  v         SRv6 Nodes             v    |
   | +-----------------+  +---------------+         +---------------+ |
   | |     NSF-1       |--|     NSF-2     | ....... |     NSF-n     | |
   | |(Network Exposure|  |(Policy Control|         | (Application  | |
   | | Function, NEF)  |  | Function, PCF)|         |  Function, AF)| |
   | +-----------------+  +---------------+         +---------------+ |
   +------------------------------------------------------------------+

         Figure 2: Intent-Based Network Management in SRv6 Networks

   A high-level network policy for SRv6 routers is constructed by the
   IBN Consumer-Facing Interface YANG data model.  On the other hand, a
   low-level network policy is constructed by the IBN NSF-Facing
   Interface YANG data model.

   To automate Network Policy Translation (NPT), IBN Controller needs a
   network policy translator performing the translation of a high-level
   network policy into the corresponding low-level network policy (i.e.,
   SRv6 policy [RFC9256]).  For this automatic NPT service, the IBN
   framework needs to associate a high-level YANG data model and a low-
   level YANG data model in an automatic manner, like a data model
   mapper [I-D.ietf-spring-sr-policy-yang],
   [I-D.yang-i2nsf-security-policy-translation].






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3.2.  IBN for SLA Guarantee

   Taking Network Service-Level Agreement (SLA) performance metrics
   (e.g., delay measurement), the simple schematic diagram is as
   follows.  Different thresholds, warning value, and alert value should
   be set for network delay in advance.  When the delay value is below
   warning, the network is normal and the business is normal.  When the
   delay is between warning value and alert value, the network
   fluctuation is abnormal, but the business is normal.  When the delay
   exceeds the alert value, both the network and business are abnormal.
   For delay in different thresholds, different measurement strategies
   should be adopted:

   *  When the network delay exceeds the alert value, or when the
      historical data predict that the delay will exceed the alert
      value, passive measurement requires 100% sampling of business
      data, and the transmission frequency of active measurement is
      modulated to the maximum.  At the same time, the log and alarm
      data of the whole network equipment are collected to realize the
      most fine-grained measurement of the network, locate the root
      cause of the problem and repair the network in time.

   *  When the network delay exceeds warning value but is lower than
      alert value, passive measurement samples 60% of business data, and
      the transmission message frequency of the active measurement is
      adjusted to the median value, and the running state data of some
      key devices in the network is collected synchronously.

   *  When the network delay is less than warning value, passive
      measurement data is sampled at 20%, and active measurement message
      frequency is adjusted to the lowest, and the network equipment
      running state of key nodes can be collected as needed.



















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           ^ms
           |
           |
           |                         XX
           |                        X X            Sampling Rate 100%
           |                       XX X
     alert +--------------------------------------------------------+
           |                      X   X             Sampling Rate 60%
           |                     X    XX
           |                    X      X                XX
           |          XX        X      X                XXX
           |          XXX       X       X              X  X
           |         XX X      X        X             X   XX
           |         X   XX    X        X  XX   XX    X    XX
   warning +-------------------------------------------------------+
           |         X    XX  X          XX X  XX X  XX      XX
           |     XX  X     X  X          X   XX   XX X        X
           |    XX X X     X  X          X   XX    XXX         X
           |   X   XX       XXX          X         XX          X
           |   X   XX       XX           X
           |        X       XX                      Sampling Rate 20%
           |
           +----------------------------------------------------------->

                  Figure 3: Network SLA Performance Metric

   The desired approach is to accurately measure the network state,
   especially when there are some issues affecting the service, but at
   the same time, reduce the resources to be employed to achieve the
   desired accuracy.

3.2.1.  Clustered Alternate-Marking Methodology

   The Clustered Alternate-Marking framework RFC 9342 [RFC9342] adds
   flexibility to Performance Measurement (PM), because it can reduce
   the order of magnitude of the packet counters.  This allows the NMI
   Orchestration and pre-Verification module to supervise, control, and
   manage PM in large networks.

   RFC 9342 [RFC9342] introduces the concept of cluster partition of a
   network.  The monitored network can be considered as a whole or split
   into clusters that are the smallest subnetworks (group-to-group
   segments), maintaining the packet loss property for each subnetwork.
   The clusters can be combined in new connected subnetworks at
   different levels, forming new clusters, depending on the level of
   detail to achieve.





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   The clustered performance measurement intent represents the spatial
   accuracy, that is the size of the subnetworks to consider for the
   monitoring.  It is possible to start without examining in depth and,
   in case of necessity, the "network zooming" approach can be used.

   This approach called "network zooming" and can be performed in two
   different ways:

   1.  change the traffic filter and select more detailed flows;

   2.  activate new measurement points by defining more specified
       clusters.

   The network-zooming approach implies that some filters, rules or flow
   identifiers are changed.  But these changes must be done in a way
   that do not affect the performance.  Therefore there could be a
   transient time to wait once the new network configuration takes
   effect.  Anyway, if the performance issue is relevant, it is likely
   to last for a time much longer than the transient time.

   The concrete steps of the clustered performance measurement intent
   are as follows:

   *  In NMI Recognition and Acquisition, the clustered performance
      measurement intent is recognized.  Then the NMI Recognition and
      Acquisition module inputs the clustered performance measurement
      intent into the NMI Translation module.

   *  The NMI Translation module analyzes the clustered performance
      measurement intent and outputs the executable measurement policy,
      such as network partition and the spatial accuracy for the
      monitoring.

   *  The NMI Orchestration and pre-Verification module arranges and
      calibrates the measurement with the specific configuration to
      split the whole network into clusters at different levels.  Note
      that, for the configuration, the YANG Data Model for the Alternate
      Marking Method [I-D.ydt-ippm-alt-mark-yang] can be used.

   *  The Data Collection and Analysis module collects the measurement
      data from the different clusters, and then send these data to the
      NMI Compliance Assessment module.  It verifies the performance for
      each cluster and send the measurement results to the user.  Note
      that, for the collection of the measurement data, the On-path
      Telemetry YANG Data Model [I-D.fz-ippm-on-path-telemetry-yang] or
      the IPFIX Alternate-Marking Information
      [I-D.gfz-opsawg-ipfix-alt-mark] can be used.




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   *  The NMI Compliance Assessment module, in case a cluster is
      experiencing a packet loss or the delay is high, notifies the NMI
      Orchestration and pre-Verification module to modify the cluster
      partition of the network for further investigation.  The network
      configuration can be immediately modified in order to perform a
      new partition of the network but only for the cluster with bad
      performance.  In this way, the problem can be localized with
      successive approximation up to a flow detailed analysis.  This is
      the so-called "closed loop" performance management.

3.3.  IBN for Cloud-Based Security Service Management

   A Cloud-Based Security Service Management is proposed in
   [I-D.jeong-i2nsf-security-management-automation].  It describes
   Security Management Automation (SMA) of cloud-based security services
   in the framework of Interface to Network Security Functions (I2NSF)
   [RFC8329].  The security management automation deals with closed-loop
   security control, security policy translation, and security audit.
   To support these three features in SMA, an augmented architecture of
   the I2NSF framework is proposed by introducing new system components
   and new interfaces.

      +------------+
      | I2NSF User |
      +------------+
             ^
             | Consumer-Facing Interface
             v
   +-------------------+     Registration     +-----------------------+
   |Security Controller|<-------------------->|Developer's Mgmt System|
   +-------------------+      Interface       +-----------------------+
             ^      ^
             |      |
             |      |   Analytics Interface   +-----------------------+
             |      +------------------------>|    I2NSF Analyzer     |
             |                                +-----------------------+
             | NSF-Facing Interface              ^       ^       ^
             |                                   |       |       |
             |                                   |       |       |
             |    +------------------------------+       |       |
             |    |              +-----------------------+       |
             |    |              |   Monitoring Interface        |
             v    v              v                               v
      +----------------+ +---------------+   +-----------------------+
      |      NSF-1     |-|     NSF-2     |...|         NSF-n         |
      |   (Firewall)   | | (Web Filter)  |   |(DDoS-Attack Mitigator)|
      +----------------+ +---------------+   +-----------------------+




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        Figure 4: Security Management Automation in I2NSF Framework

   Figure 4 shows an IBN-driven I2NSF framework for Security Management
   Automation (called SMA) of cloud-based security service management.
   I2NSF User composes a high-level security policy (as an intent) and
   delivers it to Security Controller.  Security Controller translates
   the high-level security policy into the corresponding low-level
   security policy that is understandable to Network Security Functions
   (NSFs) for actual security services.  Security Controller has a
   Security Policy Translator (SPT) for this security policy translation
   [I-D.yang-i2nsf-security-policy-translation].

   As shown in Figure 4, for closed-loop security control, this I2NSF
   framework has Monitoring Interface and Analytics Interface along with
   I2NSF Analyzer.  I2NSF Analyzer collects monitoring data from NSFs
   via Monitoring Interface.  It analyzes the monitoring data using
   Artificial Intelligence (AI) and Machine Learning (ML).  I2NSF
   Analyzers delivers a policy re-configuration message (e.g., defense
   against a new security attack ) or feedback information message
   (e.g., action for handling computing and communication resources) to
   Security Controller.  Security Controller receives the message and
   takes an appropriate action for the message, such as a security
   policy re-configuration for target NSFs and remedy action for the
   feedback information.

   Therefore, with a security policy translator and a closed-loop
   security control, we can provide service customers with IBN-based
   security services.

3.4.  IBN for IoT Device Management

   A Network Management Automation (NMA) can be provided for cellular
   network services in 5G networks
   [I-D.jeong-nmrg-ibn-network-management-automation].  This NMA is
   feasible on top of an IBN-empowered framework.  It deals with a
   closed-loop network control, network intent translator, and network
   management audit.  To support these three features in NMA, it
   specifies an architectural framework with system components and
   interfaces.  Also, this framework can support the use cases of NMA in
   5G networks such as the data aggregation of Internet of Things (IoT)
   devices, network slicing, and the Quality of Service (QoS) in
   Vehicle-to-Everything (V2X).









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      +------------+
      |  IBN User  |
      +------------+
             ^
             | Consumer-Facing Interface (Intent)
             v
   +-------------------+     Registration     +-----------------------+
   |   IBN Controller  |<-------------------->|  Vendor's Mgmt System |
   +-------------------+      Interface       +-----------------------+
             ^      ^
             |      |
             |      |   Analytics Interface   +-----------------------+
             |      +------------------------>|  IBN Analyzer (NWDAF) |
             |                                +-----------------------+
             | NSF-Facing Interface (Policy)     ^       ^       ^
             |                                   |       |       |
             |                                   |       |       |
             |    +------------------------------+       |       |
             |    |              +-----------------------+       |
             |    |              |   Monitoring Interface        |
             v    v              v                               v
      +---------------+  +---------------+        +---------------+
      |     NSF-1     |--|     NSF-2     |........|     NSF-n     |
      |(Net Exposure  |  |(Policy Control|        |  (IoT Device) |
      | Function, NEF)|  | Function, PCF)|        |               |
      +---------------+  +---------------+        +---------------+

      Figure 5: Network Management Automation in IBN Framework for 5G
                                  Networks

   Figure 5 shows an IBN framework for Network Management Automation in
   5G networks.  This framework is an I2NSF framework for cloud-based
   security services.  Like the framework for Security Management
   Automation (called SMA) of cloud-based security services, this
   framework supports an intent translation with a Network Intent
   Translator (NIT) and a closed-loop control mechanism, it realizes an
   IBN-based IoT device management in 5G networks.

3.5.  IBN for Sofware-Defined Vehicle Management

   Software-Defined Vehicle (SDV) is an electrical vehicle with a
   software platform (e.g., AUTOSAR and Eclipse SDV) towards autonomous
   vehicles in Intelligent Transportation Systems (ITS).  An SDV is
   constructed by a software platform having a cloud-native system
   (e.g., Kubernetes) and has its internal network (e.g., a giga-bit
   Ethernet).  For facilitating the easy and efficient configuration of
   networks, security, and applications in the SDV'S in-vehicle
   networks, an intent-based management is required.  An intent-based



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   management framework for SDVs is proposed by
   [I-D.jeong-opsawg-intent-based-sdv-framework].  This framework lets
   SDVs be configured and monitored by a vehicular cloud in terms of
   networks, security, and applications in SDVs.  In this framework,
   SDVs can communicate with other SDVs and infrastructure nodes for
   safe driving and infotainment services in ITS.

        SDV User      :            Translation/          : Network Ops/
         Space        :             IBS Space            :  App Space
 Fulfill              :                                  :
        +----------+  :  +------------+   +------------+ : +-----------+
        |Recognize/|---->| Translate/ |-->|   Learn/   |-->| Configure/|
        | Generate |  :  |   Refine   |   |   Plan/    | : | Provision |
        | Intent   |<----|            |   |   Render   | : |           |
        +----------+  :  +------------+   +------------+ : +-----------+
             ^        :                         ^        :       |
 ............|..................................|................|.....
             |        :                    +----------+  :       v
             |        :                    | Validate |  :  +----------+
             |        :                    +----^-----+<----| Monitor/ |
 Assure      |        :                         |        :  | Observe  |
         +--------+   :  +----------+      +----------+<----|          |
         | Report |<-----| Abstract |<-----| Analyze/ |  :  +----------+
         +--------+   :  +----------+      | Aggregate|  :
                      :                    +----------+  :

           Figure 6: The Life Cycle of IBS for SDV Management

   According to the life cycle of IBN in [RFC9315], as shown in
   Figure 6, the life cycle of an intent-based system (IBS) can be
   enforced for SDV management.  The life cycle consists of three
   spaces, namely SDV User Space, Translation & IBS Space, and Network
   Operations (Ops) & Application (App) Space.  These spaces are divided
   into two sections in the life cycle space, such as fulfillment and
   assurance.  The fulfillment section pipelines the steps for an intent
   enforcement, such as intent input, translation/refinement,
   learning/planning/rendering, and configuration/provisioning toward
   the final SFs (e.g., network functions (NFs) and applications in
   SDVs).  On the other hand, the assurance section performs the steps
   for an Intent assurance and optimization by collecting final results
   of the intent fulfillment, and validating and analyzing the resulted
   NFs and applications for SDVs.  If an action for the found problem is
   needed, the life cycle inserts a reconfigured policy into the
   fulfillment section or report a required action to SDV User.







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                         <Vehicular Cloud (VC)>
 +---------------------------------------------------------------------+
 | +------------------+                      +--------------------+    |
 | |     SDV User     |          +---------->|    SDV Database    |    |
 | +------------------+          |           +--------------------+    |
 |          ^                    |                     ^               |
 |          |                    | Database            | Database      |
 |          |                    | Interface           | Interface     |
 |          | Consumer-Facing    |                     V               |
 |          | Interface (Intent) |           +--------------------+    |
 |          |                    | +-------->|    Cloud Analyzer  |<-+ |
 |          |                    | |         +--------------------+  | |
 |          V                    | |Analytics                        | |
 | +------------------+<---------+ |Interface                        | |
 | | Cloud Controller |<-----------+         +--------------------+  | |
 | +------------------+<-------------------->|Vendor's Mgmt System|  | |
 |          ^         Registration Interface +--------------------+  | |
 |          |                                          ^             | |
 +----------|------------------------------------------|-------------|-+
            | Controller-Facing Interface   VMS-Facing |   Analyzer- |
            |     (High-level Policy)        Interface |   Facing    |
            |                                          |   Interface |
 +----------|------------------------------------------|-------------|-+
 |          |                                          |             | |
 |          v                                          v             | |
 | +------------------+     Registration     +--------------------+  | |
 | |  SDV Controller  |<-------------------->|    SDV Vendor's    |  | |
 | +------------------+      Interface       |    Mgmt System     |  | |
 |          ^      ^                         +--------------------+  | |
 |          |      |                                                 | |
 |          |      |                                                 | |
 |          |      |   Analytics Interface   +--------------------+  | |
 |          |      +------------------------>|    SDV Analyzer    |<-+ |
 |          |                                +--------------------+    |
 |          | SF-Facing Interface                      ^               |
 |          |  (Low-level Policy)                      |               |
 |          |                                          |               |
 |          |                                          |               |
 |          |    +--------------+----------------------+---+           |
 |          |    |              |   Monitoring Interface   |           |
 |          v    v              v                          v           |
 |   +---------------+  +---------------+        +---------------+     |
 |   |     SF-1      |  |     SF-2      |........|     SF-n      |     |
 |   |   (Router)    |  |  (Firewall)   |        |  (Navigator)  |     |
 |   +---------------+  +---------------+        +---------------+     |
 +---------------------------------------------------------------------+
                   <Software-Defined Vehicle (SDV)>




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    Figure 7: Intent-Based Management Framework for Software-Defined
                                Vehicles

   Figure 7 shows a framework of intent-based management for SDVs.  The
   framework consists of a vehicular cloud and SDVs.  The two parts of
   the vehicular cloud and SDV borrow the components and interfaces of
   the I2NSF framework and customize their components and interfaces for
   IBN-based SDV management.

3.6.  IBN for Interconnection

   New network capabilities based on programmability and virtualization
   are producing service situations where a connectivity-only approach
   is not sufficient.  The increasing availability of computing
   capabilities internal to the networks, or attached to them, enable
   new scenarios where those capabilities can be consumed through the
   advertisement or exposure of these execution environments (i.e., in
   terms of compute, storage and associated networking resources).  In
   addition or complementary to that, even services or network functions
   could be advertised in order to make them available for
   interconnection.  An intent-based evolved interconnection framework
   is proposed by [I-D.contreras-nmrg-interconnection-intents].

   Figure 8 captures the intent procedure for the fulfillment phase.



























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          User Space   :       Translation / IBS       :  Network Ops
                       :            Space              :     Space
                       :                               :
         +----------+  :  +----------+   +-----------+ : +-----------+
 Fulfill |recognize/|---> |translate/|-->|  learn/   |-->| configure/|
         |generate  |     |          |   |  plan/    |   | provision |
         |intent    |<--- |  refine  |   |  render   | : |           |
         +----------+  :  +----------+   +-----------+ : +-----------+
                       :                               :
 .........................................................................

       Provider A      :                   Provider B
       ----------      :                   ----------
                       :
  - Select interconn.  : - Mapping of intent types to  : - Establishment of
    intent type        :   protocols / APIs for        :   protocol sessions
  - Specify targeted   :   coveying targeted resources :   or API requests
    resources (i.e.,   : - Parametrization of that     :   for configure or
    routes, compute    :   protocols / APIs, e.g.      :   provisioning
    quotes, service    :   leveraging on data models   :   targeted resources
    functions, etc.)   :                               :
                       :                               :


      Figure 8: Fulfillment phase of the Interconnection Intent

   Similarly, Figure 9 sketches the intent procedure for the assurance
   phase.























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                         :                  +--------+   :
                         :                  |validate|   :  +----------+
                         :                  +----^---+ <----| monitor/ |
   Assure   +-------+    :  +---------+    +-----+---+   :  | observe/ |
            |report | <---- |abstract |<---| analyze | <----|          |
            +-------+    :  +---------+    |aggregate|   :  +----------+
                         :                 +---------+   :
   .....................................................................

         Provider A      :                   Provider B
         ----------      :                   ----------
                         :
    - Analysis of the    : - Checking of monitored data  : - Collection of
      reported metrics   :   for internal closed loops   :   telemetry info
      against the intent :   to ensure commited SLOs     :   related to
      request            :   (inner closed loop)         :   allocated
    - Trigger of actions : - Aggregation of data         :   resources (i.e.,
      if needed, e.g.,   :   producing an abstracted view:   routes, compute
      new intent (outer  :   fitted to the intent request:   quotes, service
      closed loop)       :                               :   functions, etc.)



       Figure 9: Assurance phase of the Interconnection Intent

   Both Fulfillment and Assurance phases are integral part of the
   interconnection intent.

3.7.  IBN for IETF Network Slices

   Network slicing is emerging as the future model for service offering
   in telecom operator networks.  Conceptually, network slicing provides
   a customer with an apparent dedicated network built on top of logical
   (i.e. virtual) and/or physical functions and resources supported by a
   shared infrastructure, provided by one or more telecom operators.  As
   part of an end-to-end network slice it is expected to have a number
   of network slices at transport level (referred as IETF network
   slices) providing the necessary connectivity to the rest of
   components of the end-to-end slice, e.g., mobile packet core slice.

   With this respect, the GSMA has been developing a universal blueprint
   that can be used by any vertical customer to request the deployment
   of a network slice instance (NSI) based on a specific set of service
   requirements.  Such a blueprint is a network slice descriptor called
   Generic Slice Template (GST).  The GST contains multiple attributes
   that can be used to characterize a network slice.  A particular
   template filled with values generates a specific Network Slice Type
   (NEST).



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   The previous slice templates provide a number of parameters that
   functionally characterizes the behavior of the network slice as
   expected by the slice customer.  However, apart from the slice
   characteristics, further information is needed in order to request
   the realization of a slice towards the IETF Network Slice controller,
   such as identification of the slice endpoints, information about the
   virtual network topology expected to form the requested IETF Network
   Slice, etc.

   An intent-based evolved interconnection framework is proposed by
   [I-D.contreras-nmrg-transport-slice-intent].

   Figure 10 captures the intent procedure for the fulfillment phase.


         User Space   :       Translation / IBS       :  Network Ops
                      :            Space              :     Space
                      :                               :
        +----------+  :  +----------+   +-----------+ : +-----------+
Fulfill |recognize/|---> |translate/|-->|  learn/   |-->| configure/|
        |generate  |     |          |   |  plan/    |   | provision |
        |intent    |<--- |  refine  |   |  render   | : |           |
        +----------+  :  +----------+   +-----------+ : +-----------+
                      :                               :
.......................................................................

    Slice Customer    :                   Slice Provider
    --------------    :                   --------------
                      :
   - Customized Slice :  - Identification of IETF     : - Slice request
     Templates        :    network slice endpoints    :   to IETF NSC
   - Service SLOs as  :    and connectivity pattern   :   by using slice
     understood by    :  - Derivation of network SLOs :   NBI YANG model
     slice customer   :    and SLEs from high-level   :
                      :    Customer Service SLOs      :
                      :                               :


Figure 10: Fulfillment phase of the IETF Network Slice service Intent

   Similarly, Figure 11 sketches the intent procedure for the assurance
   phase.









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                       :                  +--------+   :
                       :                  |validate|   :  +----------+
                       :                  +----^---+ <----| monitor/ |
 Assure   +-------+    :  +---------+    +-----+---+   :  | observe/ |
          |report | <---- |abstract |<---| analyze | <----|          |
          +-------+    :  +---------+    |aggregate|   :  +----------+
                       :                 +---------+   :
   .....................................................................

     Slice Customer    :                   Slice Provider
     --------------    :                   --------------
                       :
  - Analysis of the    : - Checking of monitored data  : - Collection of
    reported metrics   :   for internal closed loops   :   monitoring info
    against the slice  :   to ensure commited SLOs and :   related to the
    request            :   SLEs (inner closed loop)    :   slice (i.e.,
  - Trigger of actions : - Aggregation of data         :   SLOs and SLEs of
    if needed, e.g.,   :   producing an abstracted view:   connectivity
    slice modification :   fitted to the slice request :   constructs, sdp,
    (outer closed loop):                               :   etc.)



 Figure 11: Assurance phase of the IETF Network Slice service Intent

   Both Fulfillment and Assurance phases are integral part of the
   interconnection intent.

4.  Practice Learnings

4.1.  Difficulties and Challenges

   Some key learnings and takeaways can be extracted from the practices
   and implementation of IBN systems in different use cases.  Commonly,
   there involve the following technical challenges in building IBN
   systems, incluing handling the dynamic and time variant nature of the
   network, the efficient management of cross-domain resources, and the
   reliability of automatic configuration, etc.  Take Service Function
   Chaining as an example to show these challenges.

   1.  Stability in Dynamic Network Environments:

   For instance, in the space-terrestrial networks where the network
   topology is with frequent changes, it is essential to design
   efficient service function chain reconstruction and service recovery
   mechanisms.  But how to guarantee the effectiveness of the chaining
   rule in these scenarios is still a challenge.




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   2.  Collaborative Management of Cross-domain SFC:

   To ensure the network intents across multi-domain networks, intent-
   based networks should be designed with a cross-domain orchestration
   and management framework to ensure an end-to-end optimization of
   Quality of Service.

   3.  Deployment under Resource-constrained Conditions:

   It is important to consider how to effectively deploy and manage
   these service function chains within limited resources.  Methods such
   as intent negotiation can be introduced to optimize resource
   allocation.

4.2.  Future Research Directions

   Although there have been extensive research achievements from
   academic, industrial, and standardization fields, there are the
   following future research considerations.

   1.  Generic Intent model for Full Life-Cycle Assurance:

   It is necessary to construct an intent model for the full life-cycle
   from both top-to-down and down-to-top perspectives, including the
   intent input state, the intent execution state, and the intent
   completion state, etc, merged in a generic logic model.  It makes
   sense of ensuring the end-to-end guaranteed implementation of any
   network intent and verifying the intent state through consistent
   mathematical logic.

   2.  Autonomous End-to-End Network Policy Generation:

   Intent-based networks should provide the network configuration
   policies to always well understand network service in time, in
   particular towards various dynamic on-demand service requirements.
   Therefore, intent-based networks should make the network quality of
   service satisfy the users’ quality of experience from a vertical
   perspective of the network protocol or the different intent holders.
   Meanwhile, current network is based on domain-specific policy local
   optimization, and it is hard to ensure an end-to-end quality of
   service guarantee, in particular a cross-domain global optimization.
   Therefore, intent-based networks should provide an end-to-end
   optimization policies across multi-domain networking applications.

   3.  Intent Implementation with Large language Models (LLMs):






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   Large language models(LLMs) will play an important role in enhancing
   the accuracy of intent refinement, resulting from the powerful
   understanding capabilities of LLMs and the entity relationships in
   knowledge graphs.  It is also beneficial to network policy generation
   according to the network status.  Although we have involved different
   kinds of artificial intelligence models at each intent-based
   networks’ stages, there still lack of generality and accuracy.
   Meanwhile, human interference is still in the full life-cycle of
   intent-based networks, and in the future the knowledge graph assisted
   LLMs can further reduce the human intervention, and even make the
   human completely be out of the full life-cycle of the intent-based
   networks.

5.  Other Considerations

   The Integration of IBN and Network Digital Twin.(TBD)

   The Integration of IBN, AI and Green.(TBD)

6.  Security Considerations

   TBD.

7.  IANA Considerations

   This document has no requests to IANA.

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

   [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>.

   [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>.







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   [RFC8329]  Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R.
              Kumar, "Framework for Interface to Network Security
              Functions", RFC 8329, DOI 10.17487/RFC8329, February 2018,
              <https://www.rfc-editor.org/info/rfc8329>.

   [RFC9256]  Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
              A., and P. Mattes, "Segment Routing Policy Architecture",
              RFC 9256, DOI 10.17487/RFC9256, July 2022,
              <https://www.rfc-editor.org/info/rfc9256>.

   [RFC9315]  Clemm, A., Ciavaglia, L., Granville, L. Z., and J.
              Tantsura, "Intent-Based Networking - Concepts and
              Definitions", RFC 9315, DOI 10.17487/RFC9315, October
              2022, <https://www.rfc-editor.org/info/rfc9315>.

   [RFC9316]  Li, C., Havel, O., Olariu, A., Martinez-Julia, P., Nobre,
              J., and D. Lopez, "Intent Classification", RFC 9316,
              DOI 10.17487/RFC9316, October 2022,
              <https://www.rfc-editor.org/info/rfc9316>.

   [RFC9342]  Fioccola, G., Ed., Cociglio, M., Sapio, A., Sisto, R., and
              T. Zhou, "Clustered Alternate-Marking Method", RFC 9342,
              DOI 10.17487/RFC9342, December 2022,
              <https://www.rfc-editor.org/info/rfc9342>.

8.2.  Informative References

   [I-D.contreras-nmrg-interconnection-intents]
              Contreras, L. M., Lucente, P., and T. H. Velivassaki,
              "Interconnection Intents", Work in Progress, Internet-
              Draft, draft-contreras-nmrg-interconnection-intents-05, 8
              July 2024,
              <https://datatracker.ietf.org/api/v1/doc/document/draft-
              contreras-nmrg-interconnection-intents/>.

   [I-D.contreras-nmrg-transport-slice-intent]
              Contreras, L. M., Demestichas, P., and J. Tantsura, "IETF
              Network Slice Intent", Work in Progress, Internet-Draft,
              draft-contreras-nmrg-transport-slice-intent-07, 8 July
              2024, <https://datatracker.ietf.org/api/v1/doc/document/
              draft-contreras-nmrg-transport-slice-intent/>.

   [I-D.fz-ippm-on-path-telemetry-yang]
              Fioccola, G. and T. Zhou, "On-path Telemetry YANG Data
              Model", Work in Progress, Internet-Draft, draft-fz-ippm-
              on-path-telemetry-yang-00, 19 June 2024,
              <https://datatracker.ietf.org/doc/html/draft-fz-ippm-on-
              path-telemetry-yang-00>.



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   [I-D.gfz-opsawg-ipfix-alt-mark]
              Graf, T., Fioccola, G., Zhou, T., Milan, F., and M. Nilo,
              "IPFIX Alternate-Marking Information", Work in Progress,
              Internet-Draft, draft-gfz-opsawg-ipfix-alt-mark-01, 24
              April 2024, <https://datatracker.ietf.org/doc/html/draft-
              gfz-opsawg-ipfix-alt-mark-01>.

   [I-D.ietf-spring-sr-policy-yang]
              Raza, S. K., Saleh, T., Shunwan, Z., Voyer, D., Durrani,
              M., Matsushima, S., and V. P. Beeram, "YANG Data Model for
              Segment Routing Policy", Work in Progress, Internet-Draft,
              draft-ietf-spring-sr-policy-yang-03, 4 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-spring-
              sr-policy-yang-03>.

   [I-D.jeong-i2nsf-security-management-automation]
              Jeong, J. P., Lingga, P., Jung-Soo, J., Lopez, D., and S.
              Hares, "Security Management Automation of Cloud-Based
              Security Services in I2NSF Framework", Work in Progress,
              Internet-Draft, draft-jeong-i2nsf-security-management-
              automation-07, 7 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-jeong-i2nsf-
              security-management-automation-07>.

   [I-D.jeong-nmrg-ibn-network-management-automation]
              Jeong, J. P., Ahn, Y., Kim, Y., and J. Jung-Soo, "Intent-
              Based Network Management Automation in 5G Networks", Work
              in Progress, Internet-Draft, draft-jeong-nmrg-ibn-network-
              management-automation-04, 22 April 2024,
              <https://datatracker.ietf.org/doc/html/draft-jeong-nmrg-
              ibn-network-management-automation-04>.

   [I-D.jeong-opsawg-intent-based-sdv-framework]
              Jeong, J. P. and Y. Shen, "An Intent-Based Management
              Framework for Software-Defined Vehicles in Intelligent
              Transportation Systems", Work in Progress, Internet-Draft,
              draft-jeong-opsawg-intent-based-sdv-framework-02, 24 June
              2024, <https://datatracker.ietf.org/doc/html/draft-jeong-
              opsawg-intent-based-sdv-framework-02>.

   [I-D.park-nmrg-ibn-network-management-srv6]
              Jung-Soo, J., Choi, Y., and J. P. Jeong, "Intent-Based
              Network Management in SRv6 Networks", Work in Progress,
              Internet-Draft, draft-park-nmrg-ibn-network-management-
              srv6-02, 24 June 2024,
              <https://datatracker.ietf.org/doc/html/draft-park-nmrg-
              ibn-network-management-srv6-02>.




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   [I-D.yang-i2nsf-security-policy-translation]
              Jeong, J. P., Lingga, P., and J. Yang, "Guidelines for
              Security Policy Translation in Interface to Network
              Security Functions", Work in Progress, Internet-Draft,
              draft-yang-i2nsf-security-policy-translation-16, 7
              February 2024, <https://datatracker.ietf.org/doc/html/
              draft-yang-i2nsf-security-policy-translation-16>.

   [I-D.ydt-ippm-alt-mark-yang]
              Graf, T., Wang, M., Fioccola, G., Zhou, T., Min, X., Jun,
              G., Nilo, M., and L. Han, "A YANG Data Model for the
              Alternate Marking Method", Work in Progress, Internet-
              Draft, draft-ydt-ippm-alt-mark-yang-02, 4 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-ydt-ippm-alt-
              mark-yang-02>.

   [REST]     Fielding, R. and R. Taylor, "Principled Design of the
              Modern Web Architecture", ACM Transactions on Internet
              Technology, Vol. 2, Issue 2,,
              Available: https://dl.acm.org/doi/10.1145/514183.514185,
              May 2002.

Appendix A.  Changes from draft-kdj-nmrg-ibn-usecases-00

   The following changes are made from draft-kdj-nmrg-ibn-usecases-00:

   *  This version updates the abstract so that it may be synchronized
      with the main text.

   *  Figure 6 is modified so that it may be seen correctly.

Acknowledgments

   This work of Jaehoon Paul Jeong is supported by Institute of
   Information & Communications Technology Planning & Evaluation (IITP)
   grant funded by the Korea government, Ministry of Science and ICT
   (MSIT) (No.  RS-2024-00398199).

   The work of Luis M.  Contreras has been partially funded by the
   European Union under Horizon Europe project NEMO (NExt generation
   Meta Operating system) grant number 101070118.

Contributors

   The following people have substantially contributed to this document
   as co-authors:





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     Hongwei Yang
     China Mobile
     Email: yanghongwei@chinamobile.com

     Giuseppe Fioccola
     Huawei
     Email: giuseppe.fioccola@huawei.com

     Yiwen Shen
     Sungkyunkwan University
     Email: chrisshen@skku.edu

     Yoseop Ahn
     Sungkyunkwan University
     Email: ahnjs124@skku.edu

     Mose Gu
     Sungkyunkwan University
     Email: rna0415@skku.edu

     Jung-Soo Park
     Electronics and Telecommunications Research Institute
     Email: pjs@etri.re.kr

     Yun-Chul Choi
     Electronics and Telecommunications Research Institute
     Email: cyc79@etri.re.kr

Authors' Addresses

   Kehan Yao (editor)
   China Mobile
   Beijing
   100053
   China
   Email: yaokehan@chinamobile.com


   Danyang Chen (editor)
   China Mobile
   Beijing
   100053
   China
   Email: chendanyang@chinamobile.com







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   Jaehoon Paul Jeong (editor)
   Department of Computer Science and Engineering
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon
   Gyeonggi-Do
   16419
   Republic of Korea
   Phone: +82 31 299 4957
   Email: pauljeong@skku.edu
   URI:   http://iotlab.skku.edu/people-jaehoon-jeong.php


   Qin Wu
   Huawei
   Email: bill.wu@huawei.com


   Chungang Yang
   Xidian University
   Email: cgyang@xidian.edu.cn


   Luis M. Contreras
   Telefonica
   Email: luismiguel.contrerasmurillo@telefonica.com

























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