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YANG Data Models for Attacks Intelligent Detection
draft-wang-i2nsf-intelligent-detection-00

Document Type Active Internet-Draft (individual)
Authors Weilin Wang , Hua-chun Zhou , Man Li , Qi Guo , Shuangxing Deng
Last updated 2022-09-29
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draft-wang-i2nsf-intelligent-detection-00
I2NSF
Internet Draft                                           W. Wang
Intended status: Proposed Standard                       H. Zhou
                                                           M. Li
                                                           Q. Guo
                                                           S. Deng
Document: draft-wang-i2nsf-intelligent-detection-00.txt 
                                                     Beijing Jiaotong
                                                     University
Expires: February 2023                           September 2022

               YANG Data Models for Attacks Intelligent Detection

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."

Abstract
  This document describes how to extend the Interface to Network
  Security Function (I2NSF) framework to make it suitable for attacks
  intelligent detection. Intelligent detection means that the network
  can dynamically adjust detection policies based on resource status,
  traffic features, or detection results. This document describes the
  application of I2NSF Framework for Security Management Automation
  (SMA) for attacks intelligent detection in Software-Defined
  Networking (SDN) and Service Function Chaining (SFC) environment.
  This document will extend the YANG data model of Monitoring
  Interface, Analytics Interface and NSF-Facing Interface in I2NSF for
  SMA framework to make it suitable for attacks intelligent detection
  in SDN and SFC environments.

Copyright Notice

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   Copyright (c) 2022 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...................................................2
   2. Terminology....................................................3
   3. I2NSF Framework for Attacks Intelligent Detection..............4
      3.1 Components with I2NSF Framework for AID....................4
      3.2 Interfaces with I2NSF Framework for AID....................6
   4. The Extended YANG Data Models..................................6
      4.1 The Extended Monitoring Interface..........................6
         4.1.1 YANG Tree Structure of Extended Monitoring
               Interface.............................................9
         4.1.2 YANG Data Model of Extended Monitoring
               Interface............................................11
      4.2 The Extended Analytics Interface..........................29
         4.2.1 YANG Tree Structure of Extended Analytics
               Interface............................................30
         4.2.2 YANG Data Model of Extended Analytics Interface .....31
      4.3 The Extended NSF-Facing Interface.........................45
         4.3.1 YANG Tree Structure of Extended NSF-Facing YANG
               Module...............................................45
         4.3.2 YANG Data Model of Extended NSF-Facing YANG
               Module .......   ....................................46
   5. XML Examples of I2NSF Framework for AID.......................49
   6. IANA Considerations...........................................54
   7. Security Considerations.......................................54
   8. References....................................................54
      8.1 Normative References......................................54
      8.2 Informative References....................................58
   Acknowledgments..................................................59
   Author's Addresses...............................................59

1. Introduction
   I2NSF defines the framework and interface for interacting with NSFs
   [RFC8192] [RFC8329]. It is centered on the Security Controller and

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   implements consumer-facing NSFs management and configuration through
   Consumer-Facing Interface and NSF-Facing Interface. I2NSF Framework
   for Security Management Automation has added new components I2NSF
   Analyzer, new interface Monitoring Interface and Analytics Interface,
   which enable it to achieve feedback based automatic security
   management [I-D. jeong-i2nsf-security-management-automation].
   SDN relocates the control of network resources to a dedicated network
   element, namely SDN Controller, which provides a means to program,
   orchestrate, control and manage the network resources through
   software [ITU-TY.3300]. SFC [RFC7665] is a technique for ordering
   packets through different service functions. The SDN Controller can
   manage the SFC. The SDN Controller can send traffic tables to the SFC
   Classifiers (CFs) and Service Function Forwarder (SFFs), so that
   different traffic passes through different Service Function Paths
   (SFPs) according to different traffic table forwarding rules. I2NSF
   can be combined with SDN and SFC [I-D. ietf-i2nsf-applicability]. The
   application of SDN and SFC technology in I2NSF can provide more
   flexible NSFs combination for I2NSF User.
   NSF can provide a range of security-related services, such as
   detecting, blocking, or mitigating cyber-attacks [RFC8329]. The NSFs
   referred in this document specifically refers to NSFs with the
   capability to detect attacks, which are called Detection Modules
   (DMs). Different detection modules apply to different types of
   attacks, such as Distributed Denial of service (DDoS) attacks, worm
   attacks and so on. Detection modules can form different SFPs in SDN
   and SFC environments. Traffic with different features, such as
   protocols or port numbers, passes through different paths to improve
   network detection efficiency and reduce NSFs load and traffic
   transmission delay.
   This document will design extended YANG data models for Monitoring
   Interface, Analytics Interface and NSF-Facing Interface in I2NSF
   Framework for Security Management Automation. The I2NSF Analyzer can
   collect network resource information, traffic features, and detection
   results through the Extended Monitoring Interface. The I2NSF Analyzer
   can send resource alarms, detection results, and path reconfiguration
   policies to the Security Controller through the Extended Analytics
   Interface. The Security Controller can send the path configuration
   rules to the SDN Controller through the Extended NSF-facing
   Interface. The extended framework can realize closed-loop feedback
   based dynamic adjustment of attack detection policies in SDN and 
   SFC environment.

2. Terminology
   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and

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   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.
   This document uses the terminology described in [RFC8329], [I-D.
   jeong-i2nsf-security-management-automation], [RFC7665], [ITU-TY.3300]
   and [RFC8455]. In addition, the following terms are defined below:
   o   Intelligent Detection: The network can dynamically adjust
       detection policies based on the feedback resource status, traffic
       features, and detection results.
   o   Detection Module (DM): The NSF with detection capability.
       Different DMs apply to different types of attacks, such as DDoS
       attacks, worm attacks and so on.

3. I2NSF Framework for Attacks Intelligent Detection
   This section summarizes the I2NSF Framework for Attacks Intelligent
   Detection (I2NSF Framework for AID) in SDN and SFC environment. As
   shown in Figure 1, The Security Controller and I2NSF Analyzer
   implement closed-loop automatic management of SDN controller,
   CFs/SFFs and DMs through Monitoring Interface, Analytics Interface
   and NSF-Facing Interface.

3.1 Components with I2NSF Framework for AID
   The following are the system components for the I2NSF framework for
   AID.
  o I2NSF User: An entity that delivers a high-level security policy to
    Security Controller [RFC8329].
  o Security Controller: An entity that controls and manages other
    system components in the I2NSF framework. It translates a high-
    level security policy (from I2NSF User) or reconfiguration policy
    (from I2NSF Analyzer) into the corresponding low-level security
    policy. It selects appropriate NSFs (including DMs, SDN Controller,
    CFs and SFFs) to execute the security rules of the low-level
    security policy [RFC8329].

  o Developer's Management System (DMS): An entity that provides an
  image of a virtualized NSF for a security service to the I2NSF
  framework, and registers the capability and access information of
  an NSF with Security Controller [RFC8329].

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  o I2NSF Analyzer: An entity that collects monitoring data from NSFs
   and analyzes such data for checking the activity and performance
   of the NSFs. If there is a suspicious attack activity for the
   target network or NSF, I2NSF Analyzer delivers a report of the
   augmentation or generation of reconfiguration policy to Security
   Controller [I-D. jeong-i2nsf-security-management-automation].
          +----------+
          |I2NSF User|
          +----------+
                ^
                | Consumer-Facing Interface
                v
    +-------------------+     Registration  +-----------------------+
    |Security Controller|<----------------> |Developer's Mgmt System|
    +-------------------+     Interface     +-----------------------+
      ^            ^ ^
      |            | |
      |            | | Analytics Interface  +--------------+
      |            | +--------------------->|I2NSF Analyzer|
      |NSF-Facing  |                        +--------------+
      |Interface   +-------+ NSF-Facing          ^ Monitoring
      |                    | Interface           | Interface
  +-----------------------------------------------------------+
  |   v                    |                     v            |
  | +--------------+       |                                  |
  | |SDN Controller|       |                                  |
  | +--------------+       |                                  |
  |     ^                  |                                  |
  |     | SDN Southbound   |                                  |
  |     | Interface        |                                  |
  |     v                  |                                  |
  | +--------------+       v                                  |
  | | +----------+ |----------------------------------+       |
  | | |Classifier| |       |         |                |       |
  | | +----------+ |       v         v                v       |
  | |   +-----+    |   +------+ +------+           +------+   |
  | |   | SFF |    |   | DM-1 | | DM-2 |    ...    | DM-n |   |
  | |   +-----+    |   +------+ +------+           +------+   |
  | +--------------+                                          |
  +-----------------------------------------------------------+
       Figure 1: I2NSF Framework for Attacks Intelligent Detection
  o SDN Controller: An entity that provides a means to program,
  orchestrate, control and manage the network resources through
  software. It can parse path rules of the low-level security policy
  and deliver flow tables to CFs and SFFs to form SFPs [ITU-TY.3300].

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 o Detection Module (DM): The NSF with detection capability.

3.2 Interfaces with I2NSF Framework for AID
   The following are the interfaces for the AID I2NSF framework. Note
   that the interfaces are modeled with YANG [RFC6020] and security
   policies are delivered through either RESTCONF [RFC8040] or NETCONF
   [RFC6241].
  o Consumer-Facing Interface: An interface between I2NSF User and
    Security Controller for the delivery of a high-level security
    policy [RFC8329].
  o NSF-Facing Interface: An interface between Security Controller and
   an NSF for the delivery of a low-level security policy [RFC8329].

  o Registration Interface: An interface between a DMS and Security
   Controller for the registration of an NSF's capability and access
   information with Security Controller or the query of an NSF for a
   required low-level security policy [RFC8329].

  o Analytics Interface: An interface to deliver an analytics report
  for augmentation or generation of a security policy rule created
  by I2NSF Analyzer to Security Controller [I-D. jeong-i2nsf-
      security-management-automation].

  o SDN Southbound Interface: The application programming interface
  provided by the SDN Controller to interact with the SDN nodes
  [RFC8455].

4. The Extended YANG Data Models
   This section describes the extended Monitoring Interface, Analytics
   Interface and NSF-Facing Interface YANG data model.

4.1 The Extended Monitoring Interface
   This section describes the Extended Monitoring Interface. This
   document modifies or adds traffic features, resource utilization
   logs, and DM detection results for Monitoring Interface.
   Traffic features contain the following information:

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  o measurement-time: The duration of the measurement in seconds for
     the features of traffic flows. These traffic flow features are
     measured over the past measurement duration before now.
  o packets-per-second: Average number of packets forwarded per second
     measured over the past 'measurement-time'.

  o bytes-per-second: Average number of bytes forwarded per second
     measured over the past 'measurement-time'.

  o packet-size-mean: Average packet length of packets measured over
     the past 'measurement-time'.

  o src-ip-entropy: Entropy of the source IP address measured over the
     past 'measurement-time'.

  o dst-ip-entropy: The entropy of the destination IP address measured
     over the past 'measurement-time'.

  o TTL-entropy: Packet lifetime TTL entropy measured over the past
     'measurement-time'.

  o tcp-src-port-entropy: TCP Packet source port entropy measured over
     the past 'measurement-time'.

  o tcp-dst-port-entropy: TCP Packet destination port entropy measured
     over the past 'measurement-time'.

  o udp-src-port-entropy: UDP Packet source port entropy measured over
     the past 'measurement-time'.

  o udp-dst-port-entropy: UDP Packet destination port entropy measured
     over the past 'measurement-time'.

  o packet-size-entropy: The entropy of packet length measured over the
     past 'measurement-time'.

  o packets-variance: Variance of packets measured over the past
     'measurement-time'.
  Resource utilization logs contain the following information:

  o system-status: The current system's running status [I-D. ietf-
     i2nsf-nsf-monitoring-data-model].

  o cpu-usage: Specifies the aggregated CPU usage in percentage [I-D.
     ietf-i2nsf-nsf-monitoring-data-model].

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  o cpu-freq: Specifies the frequency of CPU in MHz.

  o memory-usage: Specifies the MB of memory usage.

  o memory-total: Specifies the MB of total memory.

  o memory-available: Specifies the MB of available memory.

  o disk-id: The ID of the storage disk. It is a free form identifier
     to identify the storage disk [I-D. ietf-i2nsf-nsf-monitoring-data-
     model].

  o disk-usage: Specifies the percentage of disk usage [I-D. ietf-
     i2nsf-nsf-monitoring-data-model].

  o disk-space-left: Specifies the available disk space left of disk-id
     in percentage [I-D. ietf-i2nsf-nsf-monitoring-data-model].

  o interface-id: Specifies the interface ID to identify the network
     interface [I-D. ietf-i2nsf-nsf-monitoring-data-model].

  o in-traffic-rate: The total inbound data plane traffic rate in
     packets per second [I-D. ietf-i2nsf-nsf-monitoring-data-model].

  o out-traffic-rate: The total outbound data plane traffic rate in
     packets per second [I-D. ietf-i2nsf-nsf-monitoring-data-model].

  o in-traffic-throughput: The total inbound data plane traffic
     throughput in bytes per second [I-D. ietf-i2nsf-nsf-monitoring-
     data-model].

  o out-traffic-throughput: The total outbound data plane traffic
     throughput in bytes per second[I-D. ietf-i2nsf-nsf-monitoring-
     data-model].

  o packet-loss-rate: The percentage of discarded packets.

  The DM detection result contains the following information:
 o detection-module-name: The name of the specific detection module.

 o time-stamp: Specify the time of a message being delivered.

 o response-time: The time taken for the detection.

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 o start-time: The start time for the detection.

 o end-time: The end time for the detection.

 o attack-id: The ID of the specific attack traffic which has the same
    src/dst IP, protocol and attack type.

 o attack-type: The type of the detected attack.

 o attack-src-ip: The source IPv4 or IPv6 addresses of attack traffic.

 o attack-dst-ip: The destination IPv4 or IPv6 addresses of attack
    traffic.

 o attack-src-port: The transport-layer source ports of the attack. It
    can hold multiple ports.

 o attack-dst-port: The transport-layer destination ports of the
    attack. It can hold multiple ports.

 o protocol: The type of network protocol for the attack.

 o attack-rate: The average packets per second (pps) rate of attack
    traffic [I-D. ietf-i2nsf-nsf-monitoring-data-model].

 o attack-throughput: The average bytes per second (Bps) throughput of
    attack traffic [I-D. ietf-i2nsf-nsf-monitoring-data-model].

4.1.1 YANG Tree Structure of Extended Monitoring Interface

   The tree structure of the Extended Monitoring Interface is provided
   below:
   module: wang-i2nsf-extended-monitoring-interface
     notifications:
      +---n i2nsf-event
      | +--ro vendor-name?                           string
      | +--ro device-model?                          string
      | +--ro software-version?                      string
      | +--ro nsf-name                               union
      | +--ro message?                               string
      | +--ro language?                              string
      | +--ro acquisition-method?                    identityref

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      | +--ro emission-type?                           identityref
      | +--ro dampening-type?                          identityref
      | +--ro (sub-event-type)?
      |     +--:(i2nsf-flow-features)
      |        +--ro i2nsf-traffic-flow-features
      |           +--ro measurement-time?         uint32
      |           +--ro packets-per-second?       uint64
      |           +--ro bytes-per-second?         uint64
      |           +--ro packet-size-mean?         uint64
      |           +--ro src-ip-entropy?           uint64
      |           +--ro dst-ip-entropy?           uint64
      |           +--ro TTL-entropy?              uint64
      |           +--ro tcp-src-port-entropy?     uint64
      |           +--ro tcp-dst-port-entropy?     uint64
      |           +--ro udp-src-port-entropy?     uint64
      |           +--ro udp-dst-port-entropy?     uint64
      |           +--ro packet-size-entropy?      uint64
      |           +--ro packets-variance?         uint64
      +---n i2nsf-log
      | +--ro vendor-name?                           string
      | +--ro device-model?                          string
      | +--ro software-version?                      string
      | +--ro nsf-name                               union
      | +--ro message?                               string
      | +--ro language?                              string
      | +--ro acquisition-method?  identityref
      | +--ro emission-type?          identityref
      | +--ro dampening-type?     identityref
      | +--ro (sub-logs-type)?
      |     +--:(i2nsf-system-res-util-log)
      |        +--ro i2nsf-system-res-util-log
      |           +--ro system-status?        enumeration
      |           +--ro cpu-usage?            uint8
      |           +--ro cpu-freq?             uint64
      |           +--ro memory-usage?         uint64
      |           +--ro memory-total?         uint64
      |           +--ro memory-available?     uint64
      |           +--ro disks* [disk-id]
      |           | +--ro disk-id               string
      |           | +--ro disk-usage?           uint8
      |           | +--ro disk-space-left?      uint8
      |           +--ro interface* [interface-id]
      |               +--ro interface-id                string
      |               +--ro in-traffic-rate?            uint64
      |               +--ro out-traffic-rate?           uint64
      |               +--ro in-traffic-throughput?      uint64
      |               +--ro out-traffic-throughput?     uint64
      |               +--ro packet-loss-rate?           uint64
      +---n i2nsf-nsf-event

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         +--ro vendor-name?                              string
         +--ro device-model?                             string
         +--ro software-version?                         string
         +--ro nsf-name                                  union
         +--ro message?                                  string
         +--ro language?                                 string
         +--ro acquisition-method?                       identityref
         +--ro emission-type?                            identityref
         +--ro dampening-type?                           identityref
         +--ro (sub-event-type)?
           +--:(i2nsf-nsf-detection-module)
               +--ro i2nsf-nsf-detection-module
                  +--ro detection-module* [detection-module-name]
                     +--ro detection-module-name     string
                     +--ro time-stamp?        yang:date-and-time
                     +--ro response-time?    yang:date-and-time
                     +--ro start-time?           yang:date-and-time
                     +--ro end-time?            yang:date-and-time
                     +--ro detected-attacks
                       +--ro attack-traffic* [attack-id]
                         +--ro attack-id            string
                         +--ro attack-type          string
                         +--ro attack-src-ip? inet:ip-address-no-zone
                         +--ro attack-dst-ip? inet:ip-address-no-zone
                         +--ro attack-src-port* inet:port-number
                         +--ro attack-dst-port* inet:port-number
                         +--ro protocol?  identityref
                         +--ro attack-rate?  uint64
                         +--ro attack-throughput?  uint64
      Figure 2: YANG Tree Structure of Extended Monitoring Interface

4.1.2 YANG Data Model of Extended Monitoring Interface

   This section describes a YANG module of I2NSF Extended Monitoring
   Interface. This YANG module imports from [RFC6991], and makes
   references to [I-D. ietf-i2nsf-nsf-monitoring-data-model] [RFC0768]
   [RFC0791] [RFC0792] [RFC0854] [RFC1939] [RFC0959] [RFC2595]
   [RFC4340] [RFC4443] [RFC5321] [RFC5646] [RFC6242] [RFC8200]
   [RFC8641] [RFC9051] [RFC9110] [RFC9112] [RFC9113] [RFC9260] 
   [RFC9293].
   <CODE BEGINS> file "wang-i2nsf-extended-monitoring-interface@2022-
   09-21.yang"
   module wang-i2nsf-extended-monitoring-interface{

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    yang-version 1.1;
    namespace
      "urn:ietf:params:xml:ns:yang:wang-i2nsf-extended-
           monitoring-interface";
    prefix i2nsf-exmi;
    import ietf-inet-types{
      prefix inet;
      reference "Section 4 of RFC 6991";
    }
    import ietf-yang-types{
      prefix yang;
      reference "Section 3 of RFC 6991";
    }
    organization
      "IETF I2NSF (Interface to Network Security Functions)
       Working Group";
    contact
      "WG Web: <https://datatracker.ietf.org/wg/i2nsf>
       WG List: <mailto:i2nsf@ietf.org>
       Author:   Weilin Wang
                 <mailto:21111026@bjtu.edu.cn>
       Author:   Huachun Zhou
                 <mailto:hchzhou@bjtu.edu.cn>
       Author:   Man Li
                 <mailto:20111018@bjtu.edu.cn>
       Author:   Qi Guo
                 <mailto:20120044@bjtu.edu.cn>
       Author:   Shuangxing Deng
                 <mailto:21120038@bjtu.edu.cn>
       Author:   Kun Li
                 <mailto:19111021@bjtu.edu.cn>";
    description
      "This module is a YANG module for the extension of I2NSF
       NSF Monitoring.
      The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
      'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
      'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this
      document are to be interpreted as described in BCP 14
      (RFC 2119) (RFC 8174) when, and only when, they appear

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      in all capitals, as shown here.
      Copyright (c) 2022 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 Revised 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
      (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
      for full legal notices.";
    revision "2022-09-15" {
      description "Initial revision.";
      reference
        "RFC XXXX: Extension of I2NSF NSF Monitoring Interface
         YANG Data Model";
    }
  /*
   * Identity
   */
     identity characteristics {
       description
         "Base identity for monitoring information
         characteristics.";
       reference
         "I-D: I2NSF NSF Monitoring Interface YANG Data Model";
     }
     identity acquisition-method {
       base characteristics;
       description
         "The type of acquisition-method. It can be multiple
         types at once.";
     }
     identity subscription {
       base acquisition-method;
       description
         "The acquisition-method type is subscription.";
     }
     identity query {
       base acquisition-method;
       description
         "The acquisition-method type is query.";
     }

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    identity emission-type {
      base characteristics;
      description
        "The type of emission-type.";
    }
    identity periodic {
      base emission-type;
      description
        "The emission-type type is periodic.";
    }
    identity on-change {
      base emission-type;
      description
        "The emission-type type is on-change.";
    }
    identity dampening-type {
      base characteristics;
      description
        "The type of message dampening to stop the rapid
         transmission of messages, such as on-repetition
         and no-dampening.";
    }
    identity no-dampening {
      base dampening-type;
      description
        "The dampening-type is no-dampening. No-dampening
         type does not limit the transmission for the
         messages of the same type.";
    }
    identity on-repetition {
      base dampening-type;
      description
        "The dampening-type is on-repetition. On-repetition
         type limits the transmitted on-change message to one
         message at a certain interval.";
    }
    identity protocol {
      description
        "An identity used to enable type choices in leaves
         and leaf-lists with respect to protocol metadata.
         This is used to identify the type of protocol that
         goes through the NSF.";
    }
    identity ip {
      base protocol;
      description
        "General IP protocol type.";
      reference
        "RFC0791: Internet Protocol

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         RFC8200: Internet Protocol, Version 6 (IPv6)";
    }
    identity ipv4 {
      base ip;
      description
        "IPv4 protocol type.";
      reference
        "RFC0791: Internet Protocol";
    }
    identity ipv6 {
      base ip;
      description
        "IPv6 protocol type.";
      reference
        "RFC8200: Internet Protocol, Version 6 (IPv6)";
    }
    identity icmp {
      base protocol;
      description
        "Base identity for ICMPv4 and ICMPv6 condition
         capability";
      reference
        "RFC0792: Internet Control Message Protocol
         RFC4443: Internet Control Message Protocol (ICMPv6)
         for the Internet Protocol Version 6 (IPv6)
         Specification- ICMPv6";
    }
    identity icmpv4 {
      base icmp;
      description
        "ICMPv4 protocol type.";
      reference
        "RFC0791: Internet Protocol
         RFC0792: Internet Control Message Protocol";
    }
    identity icmpv6 {
      base icmp;
      description
        "ICMPv6 protocol type.";
      reference
        "RFC8200: Internet Protocol, Version 6 (IPv6)
         RFC4443: Internet Control Message Protocol (ICMPv6)
         for the Internet Protocol Version 6 (IPv6)
         Specification";
    }
    identity transport-protocol {
      base protocol;
      description
        "Base identity for Layer 4 protocol condition

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         capabilities, e.g., TCP, UDP, SCTP, DCCP, and
         ICMP.";
    }
    identity tcp {
      base transport-protocol;
      description
        "TCP protocol type.";
      reference
        "[RFC9293]: Transmission Control
         Protocol (TCP).";
    }
    identity udp {
      base transport-protocol;
      description
        "UDP protocol type.";
      reference
        "RFC0768: User Datagram Protocol";
    }
    identity sctp {
      base transport-protocol;
      description
        "Identity for SCTP condition capabilities";
      reference
        "RFC9260: Stream Control
         Transmission Protocol";
    }
    identity dccp {
      base transport-protocol;
      description
        "Identity for DCCP condition capabilities";
      reference
        "RFC4340: Datagram Congestion Control Protocol";
    }
    identity application-protocol {
      base protocol;
      description
        "Base identity for Application protocol. Note that a
        subset of application protocols (e.g., HTTP, HTTPS,
        FTP, POP3, and IMAP) are handled in this YANG module,
        rather than all the existing application protocols.";
    }
    identity http {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
         version 1.1 (HTTP/1.1).";
      reference
        "[RFC9110]: HTTP Semantics
         [RFC9112]: HTTP/1.1";

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    }
    identity https {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
         version 1.1 (HTTP/1.1) over TLS.";
      reference
        "[RFC9110]: HTTP Semantics
         [RFC9112]: HTTP/1.1";
    }
    identity http2 {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
         version 2 (HTTP/2).";
      reference
        "RFC9113: HTTP/2";
    }
    identity https2 {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
         version 2 (HTTP/2) over TLS.";
      reference
        "RFC9113: HTTP/2";
    }
    identity ftp {
      base application-protocol;
      description
        "FTP protocol type.";
      reference
        "RFC0959: File Transfer Protocol";
    }
    identity ssh {
      base application-protocol;
      description
        "SSH protocol type.";
      reference
        "RFC6242: Using the NETCONF Protocol over
         Secure Shell (SSH)";
    }
    identity telnet {
      base application-protocol;
      description
        "The identity for telnet.";
      reference
        "RFC0854: Telnet Protocol";
    }
    identity smtp {

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      base application-protocol;
      description
        "The identity for smtp.";
      reference
        "RFC5321: Simple Mail Transfer Protocol (SMTP)";
    }
    identity pop3 {
      base application-protocol;
      description
        "The identity for Post Office
         Protocol 3 (POP3).";
      reference
        "RFC1939: Post Office Protocol - Version 3 
         (POP3)";
    }
    identity pop3s {
      base application-protocol;
      description
        "The identity for Post Office Protocol 3
         (POP3) over TLS";
      reference
        "RFC1939: Post Office Protocol -Version 3(POP3)
        RFC2595: Using TLS with IMAP, POP3 and ACAP";
    }
    identity imap {
      base application-protocol;
      description
        "The identity for Internet Message Access
         Protocol (IMAP).";
      reference
        "RFC9051: Internet Message Access Protocol
         (IMAP) - Version 4rev2";
    }
    identity imaps {
      base application-protocol;
      description
        "The identity for Internet Message Access
         Protocol (IMAP) over TLS";
      reference
        "RFC9051: Internet Message Access Protocol
                    (IMAP) - Version 4rev2
         RFC2595: Using TLS with IMAP, POP3 and ACAP";
    }
  /*
   * Grouping
   */
    grouping common-monitoring-data {
      description

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        "A set of common monitoring data that is needed
        as the basic information.";
      leaf vendor-name {
        type string;
        description
          "The name of the NSF vendor. The string is
           unrestricted to identify the provider or
           vendor of the NSF.";
      }
      leaf device-model {
        type string;
        description
          "The model of the device, can be represented
           by the device model name or serial number.
           This field is used to identify the model of
           the device that provides the security
           service.";
      }
      leaf software-version {
        type string;
        description
          "The version of the software used to provide the
          security service.";
      }
      leaf nsf-name {
        type union{
          type string;
          type inet:ip-address-no-zone;
        }
        mandatory true;
        description
          "The name or IP address of the NSF generating
           the message.If the given nsf-name is not an
           IP address, the name can be an arbitrary string
           including a FQDN (Fully Qualified Domain Name).
           The name MUST be unique in the scope of
           management domain for a different NSF to
           identify the NSF that generates the message.";
      }
    }
    grouping message {
      description
        "A set of common monitoring data that is needed
        as the basic information.";
      leaf message {
        type string;
        description
          "This is a freetext annotation for
          monitoring a notification's content.";
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      }
      leaf language {
        type string {
          pattern '((([A-Za-z]{2,3}(-[A-Za-z]{3}(-[A-Za-z]{3})'
            + '{0,2})?)|[A-Za-z]{4}|[A-Za-z]{5,8})(-[A-Za-z]{4})?'
            + '(-([A-Za-z]{2}|[0-9]{3}))?(-([A-Za-z0-9]{5,8}'
            + '|([0-9][A-Za-z0-9]{3})))*(-[0-9A-WYZa-wyz]'
            + '(-([A-Za-z0-9]{2,8}))+)*(-[Xx](-([A-Za-z0-9]'
            + '{1,8}))+)?|[Xx](-([A-Za-z0-9]{1,8}))+|'
            + '(([Ee][Nn]-[Gg][Bb]-[Oo][Ee][Dd]|[Ii]-'
            + '[Aa][Mm][Ii]|[Ii]-[Bb][Nn][Nn]|[Ii]-'
            + '[Dd][Ee][Ff][Aa][Uu][Ll][Tt]|[Ii]-'
            + '[Ee][Nn][Oo][Cc][Hh][Ii][Aa][Nn]'
            + '|[Ii]-[Hh][Aa][Kk]|'
            + '[Ii]-[Kk][Ll][Ii][Nn][Gg][Oo][Nn]|'
            + '[Ii]-[Ll][Uu][Xx]|[Ii]-[Mm][Ii][Nn][Gg][Oo]|'
            + '[Ii]-[Nn][Aa][Vv][Aa][Jj][Oo]|[Ii]-[Pp][Ww][Nn]|'
            + '[Ii]-[Tt][Aa][Oo]|[Ii]-[Tt][Aa][Yy]|'
            + '[Ii]-[Tt][Ss][Uu]|[Ss][Gg][Nn]-[Bb][Ee]-[Ff][Rr]|'
            + '[Ss][Gg][Nn]-[Bb][Ee]-[Nn][Ll]|[Ss][Gg][Nn]-'
            + '[Cc][Hh]-[Dd][Ee])|([Aa][Rr][Tt]-'
            + '[Ll][Oo][Jj][Bb][Aa][Nn]|[Cc][Ee][Ll]-'
            + '[Gg][Aa][Uu][Ll][Ii][Ss][Hh]|'
            + '[Nn][Oo]-[Bb][Oo][Kk]|[Nn][Oo]-'
            + '[Nn][Yy][Nn]|[Zz][Hh]-[Gg][Uu][Oo][Yy][Uu]|'
            + '[Zz][Hh]-[Hh][Aa][Kk][Kk][Aa]|[Zz][Hh]-'
            + '[Mm][Ii][Nn]|[Zz][Hh]-[Mm][Ii][Nn]-'
            + '[Nn][Aa][Nn]|[Zz][Hh]-[Xx][Ii][Aa][Nn][Gg])))';
        }
        default "en-US";
        description
          "The value in this field indicates the language tag
          used for the human readable fields (i.e., '../message',
          '/i2nsf-log/i2nsf-nsf-system-access-log/output', and
          '/i2nsf-log/i2nsf-system-user-activity-log/additional-info
          /cause').
          The attribute is encoded following the rules in Section 2.1
          in RFC 5646. The default language tag is 'en-US'";
        reference
          "RFC 5646: Tags for Identifying Languages.";
      }
    }
    grouping characteristics {
      description
        "A set of characteristics of a monitoring information.";
      leaf acquisition-method {
        type identityref {
          base acquisition-method;
        }

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        description
          "The acquisition-method for characteristics";
       }
       leaf emission-type {
         when "derived-from-or-self(../acquisition-method, "
           + "'i2nsf-exmi:subscription')";
         type identityref {
           base emission-type;
         }
         description
           "The emission-type for characteristics. This attribute is
            used only when the acquisition-method is a
  'subscription'.";
       }
     }
     grouping characteristics-extended {
       description
         "An extended characteristics for the monitoring
  information.";
       uses characteristics;
       leaf dampening-type {
         type identityref {
           base dampening-type;
         }
         description
           "The dampening-type for characteristics";
       }
     }
     grouping attack-rates {
       description
         "A set of traffic rates for monitoring attack traffic data.";
       leaf attack-rate {
         type uint64;
         units "pps";
         description
           "The average packets per second (pps) rate of
            attack traffic.";
       }
       leaf attack-throughput {
         type uint64;
         units "Bps";
         description
           "The average bytes per second (Bps) throughput of
           attack traffic.";
       }
     }
  /*
   * Notification nodes
   */

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    notification i2nsf-event {
      description
        "Notification for I2NSF Event. This notification provides
        general information that can be supported by most types of
        NSFs.";
      uses common-monitoring-data;
      uses message;
      uses characteristics-extended;
      choice sub-event-type {
        description
          "This choice must be augmented with cases for each allowed
          sub-event. Only 1 sub-event will be instantiated in each
          i2nsf-event message. Each case is expected to define one
          container with all the sub-event fields.";
        case i2nsf-flow-features {
          container i2nsf-traffic-flow-features {
            description
              "This notification is sent to inform about the traffic
               flow features.";
            leaf measurement-time {
              type uint32;
              units "seconds";
              description
                "The duration of the measurement in seconds
                 for the features of traffic flows. These
                 traffic flow features are measured over the
                 past measurement duration before now.";
            }
            leaf packets-per-second {
              type uint64;
              description
                "Average number of packets forwarded per
                 second measured over the past 'measurement-time'.";
            }
            leaf bytes-per-second {
              type uint64;
              description
                "Average number of bytes forwarded per second
                 measured over the past 'measurement-time'.";
            }
            leaf packet-size-mean {
              type uint64;
              description
                "Average packet length of packets measured over
                the past 'measurement-time'.";
            }

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               leaf src-ip-entropy {
                 type uint64;
                 description
                   "Entropy of the source IP address measured over
                   the past 'measurement-time'.";
               }
               leaf dst-ip-entropy {
                 type uint64;
                 description
                   "The entropy of the destination IP address
                    measured over the past 'measurement-time'.";
               }
               leaf TTL-entropy {
                 type uint64;
                 description
                   "Packet lifetime TTL entropy measured over
                   the past 'measurement-time'.";
               }
               leaf tcp-src-port-entropy {
                 type uint64;
                 description
                   "TCP Packet source port entropy measured
                   over the past 'measurement-time'.";
               }
               leaf tcp-dst-port-entropy {
                 type uint64;
                 description
                   "TCP Packet destination port entropy measured
                   over the past 'measurement-time'.";
               }
               leaf udp-src-port-entropy {
                 type uint64;
                 description
                   "UDP Packet source port entropy measured
                   over the past 'measurement-time'.";
               }
               leaf udp-dst-port-entropy {
                 type uint64;
                 description
                   "UDP Packet destination port entropy measured
                   over the past 'measurement-time'.";
               }
               leaf packet-size-entropy {
                 type uint64;
                 description
                   "The entropy of packet length measured over the
                   past 'measurement-time'.";
               }
               leaf packets-variance {

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                      type uint64;
                      description
                        "Variance of packets measured over the
                         past 'measurement-time'.";
                  }
              }
          }
      }
    }
    notification i2nsf-log {
      description
        "Notification for I2NSF log. The notification
        is generated from the logs of the NSF.";
      uses common-monitoring-data;
      uses message;
      uses characteristics-extended;
      choice sub-logs-type {
        description
          "This choice must be augmented with cases for each
           allowed sub-logs. Only 1 sub-event will be
           instantiated in each i2nsf-logs message. Each case
           is expected to define one container with all the
           sub-logs fields.";
        case i2nsf-system-res-util-log {
          container i2nsf-system-res-util-log {
            description
              "This notification is sent, if there is a new log
              entry representing resource utilization updates.";
            leaf system-status {
              type enumeration {
                enum running {
                  description
                    "The system is active and running the
                     security service.";
                }
                enum waiting {
                  description
                    "The system is active but waiting for an
                    event to provide the security service.";
                }
                enum inactive {
                  description
                    "The system is inactive and not running the
                    security service.";
                }
              }
              description

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                   "The current system's running status.";
               }
               leaf cpu-usage {
                 type uint8;
                 units "percent";
                 description
                   "Specifies the aggregated CPU usage in 
                     percentage.";
               }
               leaf cpu-freq {
                 type uint64;
                 units "MHz";
                 description
                   "Specifies the frequency of CPU in MHz.";
               }
               leaf memory-usage {
                 type uint64;
                 units "MB";
                 description
                   "Specifies the MB of memory usage.";
               }
               leaf memory-total {
                 type uint64;
                 units "MB";
                 description
                   "Specifies the MB of total memory.";
               }
               leaf memory-available {
                 type uint64;
                 units "MB";
                 description
                   "Specifies the MB of available memory.";
               }
               list disks {
                 key disk-id;
                 description
                   "Disk is the hardware to store information for a
                   long period, i.e., Hard Disk or Solid-State Drive.";
                 leaf disk-id {
                   type string;
                   description
                     "The ID of the storage disk. It is a free form
                     identifier to identify the storage disk.";
                 }
                 leaf disk-usage {
                   type uint8;
                   units "percent";
                   description
                     "Specifies the percentage of disk usage.";
                 }

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                 leaf disk-space-left {
                   type uint8;
                   units "percent";
                   description
                     "Specifies the available disk space left of
                      disk-id in percentage.";
                 }
               }
               list interface {
                 key interface-id;
                 description
                   "The network interface for connecting a device
                    with the network.";
                 leaf interface-id {
                   type string;
                   description
                     "The ID of the network interface. It is a free
                     form identifier to identify the network
                     interface.";
                 }
                 leaf in-traffic-rate {
                   type uint64;
                   units "pps";
                   description
                     "The total inbound traffic rate in packets
                     per second";
                 }
                 leaf out-traffic-rate {
                   type uint64;
                   units "pps";
                   description
                     "The total outbound traffic rate in packets
                     per second";
                 }
                 leaf in-traffic-throughput {
                   type uint64;
                   units "Bps";
                   description
                     "The total inbound traffic throughput in
                     bytes per second";
                 }
                 leaf out-traffic-throughput {
                   type uint64;
                   units "Bps";
                   description
                     "The total outbound traffic throughput in
                      bytes per second.";
                 }
                 leaf packet-loss-rate {

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                        type uint64;
                        units "percent";
                        description
                          "The percentage of discarded packets.";
                    }
                }
            }
        }
      }
    }
    notification i2nsf-nsf-event {
      description
        "Notification for I2NSF NSF Event. This notification
        provides specific information that can only be
        provided by an NSF that supports additional features
        (e.g., DDoS attack detection).";
      uses common-monitoring-data;
      uses message;
      uses characteristics-extended;
      choice sub-event-type {
        description
        "This choice must be augmented with cases for
         each allowed sub-event. Only 1 sub-event will be
         instantiated in each container with all the
         sub-event fields.";
        case i2nsf-nsf-detection-module {
          container i2nsf-nsf-detection-module {
            description
              "This notification is sent, when a specific
                attack is detected.";
            list detection-module {
              key detection-module-name;
              description
              "The specific detection module.";
              leaf detection-module-name {
                 type string;
                 description
                 "The name of the specific detection module.";
              }
              leaf time-stamp {
                 type yang:date-and-time;
                 description
                 "Specify the time of a message being delivered.";
              }
              leaf response-time {
                 type yang:date-and-time;
                 description

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                 "The time taken for the detection.";
               }
               leaf start-time {
                 type yang:date-and-time;
                 description
                 "The start time for the detection.";
               }
               leaf end-time {
                 type yang:date-and-time;
                 description
                 "The end time for the detection.";
               }
               container detected-attacks {
                 description
                 "The information of detected attacks.";
                 list attack-traffic{
                   key attack-id;
                   description
                   "The five-tuple (src/dst ip, port and protocol)
                   and attack type information of specific attack
                   traffic.";
                   leaf attack-id {
                     type string;
                     description
                     "The ID of the specific attack traffic which
                     has the same src/dst IP,protocol and attack
                     type.";
                   }
                   leaf attack-type {
                     type string;
                     description
                     "The type of the detected attack.";
                   }
                   leaf attack-src-ip {
                     type inet:ip-address-no-zone;
                     description
                       "The source IPv4 or IPv6 addresses of attack
                       traffic. ";
                   }
                   leaf attack-dst-ip {
                     type inet:ip-address-no-zone;
                     description
                       "The destination IPv4 or IPv6 addresses of
                       attack traffic. ";
                   }
                   leaf-list attack-src-port {
                     type inet:port-number;
                     description
                       "The transport-layer source ports of the

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                         attack. It can hold multiple ports.";
                    }
                    leaf-list attack-dst-port {
                       type inet:port-number;
                       description
                           "The transport-layer destination
                            ports of the attack. It can hold multiple
                            ports.";
                     }
                     leaf protocol {
                       type identityref {
                          base protocol;
                        }
                        description
                           "The type of network protocol for the 
                             attack.";
                         }
                         uses attack-rates;
                     }
                  }
               }
             }
           }
         }
       }
     }
   <CODE ENDS>

4.2 The Extended Analytics Interface
   This section describes the Extended Analytics Interface. The I2NSF
   Analyzer sends feedback information and reconfiguration policies to
   the Security Controller through this interface. The reconfiguration
   policy in this document specifically refers to the path
   reconfiguration policy.
   The system feedback information refers to [I-D. lingga-i2nsf-
   analytics-interface-dm], including the following information:
   memory, CPU, disk, and interface alarm.
   The NSF feedback in this document specifically refers to the DM
   feedback, which is the same as the detection results defined in the
   Extended Monitoring Interface.
   The path reconfiguration policy is a new NSF path generated by
   analyzing traffic features or detection results through the I2NSF
   Analyzer to better detect attacks. The path reconfiguration policy
   contains the following information:

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   o name: The name of the reconfiguration policy.
   o path-id: Identify the different service function paths.

   o nsf-name: Use the name to identify the NSF.

   o sequence-number: Identifies the sequence of the NSF in the service
      function path.

4.2.1 YANG Tree Structure of Extended Analytics Interface

   The tree structure of the Extended Analytics Interface is provided
   below:
   module: wang-i2nsf-extended-analytics-interface
     +--rw i2nsf-feedback-information* [time-stamp]
     | +--rw time-stamp                       yang:date-and-time
     | +--rw message?                         string
     | +--rw language?                        string
     | +--rw system-feedback-information
     | | +--rw (alarm-type)?
     | |      +--:(memory-alarm)
     | |      | +--rw memory-alarm
     | |      |     +--rw usage?       uint8
     | |      |     +--rw duration?    uint32
     | |      +--:(cpu-alarm)
     | |      | +--rw cpu-alarm
     | |      |     +--rw usage?       uint8
     | |      |     +--rw duration?    uint32
     | |      +--:(disk-alarm)
     | |      | +--rw disk-alarm
     | |      |     +--rw disk-id?     string
     | |      |     +--rw usage?       uint8
     | |      |     +--rw duration?    uint32
     | |      +--:(interface-alarm)
     | |         +--rw interface-alarm
     | |            +--rw interface-id?       string
     | |            +--rw interface-state?    enumeration
     | |            +--rw duration?           uint32
     | +--rw nsf-feedback-information
     |     +--rw (nsf-type)?
     |        +--:(detection-module)
     |           +--rw detection-module
     |              +--rw detection-module-name?     string
     |              +--rw detected-attacks
     |                 +--rw attack-traffic* [attack-id]
     |                    +--rw attack-id              string

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     |                    +--rw attack-src-ip? inet:ip-address-no-zone
     |                    +--rw attack-dst-ip? inet:ip-address-no-zone
     |                    +--rw attack-src-port*     inet:port-number
     |                    +--rw attack-dst-port*     inet:port-number
     |                    +--rw protocol?            identityref
     |                    +--rw attack-rate?         uint64
     |                    +--rw attack-throughput?   uint64
     +--rw i2nsf-reconfiguration-policy* [name]
        +--rw name                                 string
        +--rw (policy-type)?
           +--:(path-reconfiguration-policy)
              +--rw path-reconfiguration-policy
                 +--rw service-function-path* [path-id]
                    +--rw path-id                  string
                    +--rw nsfs
                       +--rw nsf* [nsf-name]
                          +--rw nsf-name           string
                          +--rw sequence-number?   uint64
        Figure3 YANG Tree Structure of Extended Analytics Interface

4.2.2 YANG Data Model of Extended Analytics Interface

   This section describes a YANG module of I2NSF Extended Analytics
   interface. This YANG module imports from [RFC6991], and makes
   references to [I-D. lingga-analytics-interface-dm] [RFC0768]
   [RFC0791] [RFC0792] [RFC0854] [RFC1939] [RFC0959] [RFC2595]
   [RFC4340] [RFC4443] [RFC5321] [RFC5646] [RFC6242] [RFC8200]
   [RFC9051] [RFC9110] [RFC9112] [RFC9113] [RFC9260] [RFC9293].
   <CODE BEGINS> file "wang-i2nsf-extended-analytics-interface@2022-09-
   21.yang"
   module wang-i2nsf-extended-analytics-interface {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:wang-i2nsf-extension-
        analytics-interface";
     prefix i2nsf-exai;
     import ietf-inet-types {
       prefix inet;
       reference "RFC6991";
     }
     import ietf-yang-types {

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        prefix yang;
        reference "RFC6991";
    }
    organization
      "IETF I2NSF (Interface to Network Security Functions)
       Working Group";
    contact
      "WG Web: <https://datatracker.ietf.org/wg/i2nsf>
       WG List: <mailto:i2nsf@ietf.org>
         Author: Weilin Wang
         <mailto:21111026@bjtu.edu.cn>
         Author: Qi Guo
         <mailto:20120044@bjtu.edu.cn>
         Author: Shuangxing Deng
         <mailto:21120038@bjtu.edu.cn>";
    description
      "This module is a YANG module for the extension of I2NSF
       Analytics Interface.
         The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
         'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
         'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this
         document are to be interpreted as described in BCP 14
         (RFC 2119) (RFC 8174) when, and only when, they appear
         in all capitals, as shown here.
         Copyright (c) 2022 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 Revised 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
         (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
         for full legal notices.";
    revision "2022-09-19"{
      description "Initial revision.";
      reference
        "RFC XXXX: Extension of I2NSF NSF Analytics Interface

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         YANG Data Model";
    }
  /*
   *Identity
   */
     identity protocol {
       description
         "An identity used to enable type choices in leaves
         and leaf-lists with respect to protocol metadata. This is used
         to identify the type of protocol that goes through the NSF.";
     }
     identity ip {
       base protocol;
       description
         "General IP protocol type.";
       reference
         "RFC0791: Internet Protocol
          RFC8200: Internet Protocol, Version 6 (IPv6)";
     }
     identity ipv4 {
       base ip;
       description
         "IPv4 protocol type.";
       reference
         "RFC0791: Internet Protocol";
     }
     identity ipv6 {
       base ip;
       description
         "IPv6 protocol type.";
       reference
         "RFC8200: Internet Protocol, Version 6 (IPv6)";
     }
     identity icmp {
       base protocol;
       description
         "Base identity for ICMPv4 and ICMPv6 condition capability";
       reference
         "RFC0792: Internet Control Message Protocol
          RFC4443: Internet Control Message Protocol (ICMPv6)
          for the Internet Protocol Version 6 (IPv6) Specification
          - ICMPv6";
     }
     identity icmpv4 {
       base icmp;
       description
         "ICMPv4 protocol type.";
       reference

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        "RFC0791: Internet Protocol
         RFC0792: Internet Control Message Protocol";
    }
    identity icmpv6 {
      base icmp;
      description
        "ICMPv6 protocol type.";
      reference
        "RFC8200: Internet Protocol, Version 6 (IPv6)
         RFC4443: Internet Control Message Protocol (ICMPv6)
         for the Internet Protocol Version 6 (IPv6)
         Specification";
    }
    identity transport-protocol {
      base protocol;
      description
        "Base identity for Layer 4 protocol condition
        capabilities, e.g., TCP, UDP, SCTP, DCCP, and ICMP.";
    }
    identity tcp {
      base transport-protocol;
      description
        "TCP protocol type.";
      reference
        "[RFC9293]: Transmission
         Control Protocol (TCP).";
    }
    identity udp {
      base transport-protocol;
      description
        "UDP protocol type.";
      reference
        "RFC0768: User Datagram Protocol";
    }
    identity sctp {
      base transport-protocol;
      description
        "Identity for SCTP condition capabilities";
      reference
        "RFC9260: Stream
         Control Transmission Protocol";
    }
    identity dccp {
      base transport-protocol;
      description
        "Identity for DCCP condition capabilities";
      reference
        "RFC4340: Datagram Congestion Control Protocol";
    }

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    identity application-protocol {
      base protocol;
      description
        "Base identity for Application protocol. Note
         that a subset of application protocols (e.g.,
         HTTP, HTTPS, FTP, POP3, and IMAP) are handled
         in this YANG module, rather than all the
         existing application protocols.";
    }
    identity http {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
         version 1.1 (HTTP/1.1).";
      reference
        "[RFC9110]: HTTP Semantics
         [RFC9112]: HTTP/1.1";
    }
    identity https {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
        version 1.1 (HTTP/1.1) over TLS.";
      reference
        "[RFC9110]: HTTP Semantics
         [RFC9112]: HTTP/1.1";
    }
    identity http2 {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
        version 2 (HTTP/2).";
      reference
        "RFC9113: HTTP/2";
    }
    identity https2 {
      base application-protocol;
      description
        "The identity for Hypertext Transfer Protocol
        version 2 (HTTP/2) over TLS.";
      reference
        "RFC9113: HTTP/2";
    }
    identity ftp {
      base application-protocol;
      description
        "FTP protocol type.";
      reference
        "RFC 0959: File Transfer Protocol";
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    }
    identity ssh {
      base application-protocol;
      description
        "SSH protocol type.";
      reference
        "RFC6242: Using the NETCONF Protocol over
         Secure Shell (SSH)";
    }
    identity telnet {
      base application-protocol;
      description
        "The identity for telnet.";
      reference
        "RFC 0854: Telnet Protocol";
    }
    identity smtp {
      base application-protocol;
      description
        "The identity for smtp.";
      reference
        "RFC 5321: Simple Mail Transfer
         Protocol (SMTP)";
    }
    identity pop3 {
      base application-protocol;
      description
        "The identity for Post Office
         Protocol 3 (POP3).";
      reference
        "RFC1939: Post Office Protocol
         - Version 3 (POP3)";
    }
    identity pop3s {
      base application-protocol;
      description
        "The identity for Post Office Protocol
         3 (POP3) over TLS";
      reference
        "RFC1939: Post Office Protocol
         - Version 3 (POP3)
        RFC2595: Using TLS with IMAP, POP3 and ACAP";
    }
    identity imap {
      base application-protocol;
      description
        "The identity for Internet Message Access
         Protocol (IMAP).";
      reference

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        "RFC9051: Internet Message Access Protocol
         (IMAP) - Version 4rev2";
    }
    identity imaps {
      base application-protocol;
      description
        "The identity for Internet Message Access
         Protocol (IMAP) over TLS";
      reference
        "RFC9051: Internet Message Access Protocol
                   (IMAP) - Version 4rev2
         RFC2595: Using TLS with IMAP, POP3 and ACAP";
    }
  /*
   *Grouping
   */
    grouping message {
      description
        "A set of common monitoring data that is needed
        as the basic information.";
      leaf message {
        type string;
        description
          "This is a free text annotation for
          monitoring a notification's content.";
      }
      leaf language {
        type string {
          pattern '((([A-Za-z]{2,3}(-[A-Za-z]{3}(-[A-Za-z]{3})'
            + '{0,2})?)|[A-Za-z]{4}|[A-Za-z]{5,8})(-[A-Za-z]{4})?'
            + '(-([A-Za-z]{2}|[0-9]{3}))?(-([A-Za-z0-9]{5,8}'
            + '|([0-9][A-Za-z0-9]{3})))*(-[0-9A-WYZa-wyz]'
            + '(-([A-Za-z0-9]{2,8}))+)*(-[Xx](-([A-Za-z0-9]'
            + '{1,8}))+)?|[Xx](-([A-Za-z0-9]{1,8}))+|'
            + '(([Ee][Nn]-[Gg][Bb]-[Oo][Ee][Dd]|[Ii]-'
            + '[Aa][Mm][Ii]|[Ii]-[Bb][Nn][Nn]|[Ii]-'
            + '[Dd][Ee][Ff][Aa][Uu][Ll][Tt]|[Ii]-'
            + '[Ee][Nn][Oo][Cc][Hh][Ii][Aa][Nn]'
            + '|[Ii]-[Hh][Aa][Kk]|'
            + '[Ii]-[Kk][Ll][Ii][Nn][Gg][Oo][Nn]|'
            + '[Ii]-[Ll][Uu][Xx]|[Ii]-[Mm][Ii][Nn][Gg][Oo]|'
            + '[Ii]-[Nn][Aa][Vv][Aa][Jj][Oo]|[Ii]-[Pp][Ww][Nn]|'
            + '[Ii]-[Tt][Aa][Oo]|[Ii]-[Tt][Aa][Yy]|'
            + '[Ii]-[Tt][Ss][Uu]|[Ss][Gg][Nn]-[Bb][Ee]-[Ff][Rr]|'
            + '[Ss][Gg][Nn]-[Bb][Ee]-[Nn][Ll]|[Ss][Gg][Nn]-'
            + '[Cc][Hh]-[Dd][Ee])|([Aa][Rr][Tt]-'
            + '[Ll][Oo][Jj][Bb][Aa][Nn]|[Cc][Ee][Ll]-'

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            +   '[Gg][Aa][Uu][Ll][Ii][Ss][Hh]|'
            +   '[Nn][Oo]-[Bb][Oo][Kk]|[Nn][Oo]-'
            +   '[Nn][Yy][Nn]|[Zz][Hh]-[Gg][Uu][Oo][Yy][Uu]|'
            +   '[Zz][Hh]-[Hh][Aa][Kk][Kk][Aa]|[Zz][Hh]-'
            +   '[Mm][Ii][Nn]|[Zz][Hh]-[Mm][Ii][Nn]-'
            +   '[Nn][Aa][Nn]|[Zz][Hh]-[Xx][Ii][Aa][Nn][Gg])))';
        }
        default "en-US";
        description
          "The value in this field indicates the language tag
          used for the human readable fields (i.e., '../message',
          '/i2nsf-log/i2nsf-nsf-system-access-log/output', and
          '/i2nsf-log/i2nsf-system-user-activity-log/additional-info
          /cause').
          The attribute is encoded following the rules in Section 2.1
          in RFC5646. The default language tag is 'en-US'";
        reference
          "RFC5646: Tags for Identifying Languages.";
      }
    }
    grouping attack-rates {
      description
        "A set of traffic rates for monitoring
         attack traffic data.";
      leaf attack-rate {
        type uint64;
        units "pps";
        description
          "The average packets per second (pps)
           rate of attack traffic";
      }
      leaf attack-throughput {
        type uint64;
        units "Bps";
        description
          "The average bytes per second (Bps)
           throughput of attack traffic";
      }
    }
    list i2nsf-feedback-information {
      key time-stamp;
      description
        "Feedback information includes system
         feedback information about resources
          and NSF feedback information.";
      leaf time-stamp {
        type yang:date-and-time;
        description

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        "Specify the time of the information
         being delivered.";
      }
      uses message;
      container system-feedback-information {
        description
          "The resources alarm about CPU, memory,
            disks or interfaces will be sent to
            I2NSF security controller.";
        choice alarm-type {
          description
             "The alarm type.";
          case memory-alarm {
             container memory-alarm {
               description
                 "The container for memory alarm.";
               leaf usage {
                 type uint8 {
                    range "0..100";
                 }
                 units "percent";
                 description
                    "The average usage for the duration
                     of the alarm.";
               }
               leaf duration {
                 type uint32;
                 description
                    "Specify the duration of the first
                     alarm triggered until the feedback
                     information is created.";
               }
             }
          }
          case cpu-alarm {
             container cpu-alarm {
               description
                 "The case for CPU alarm.";
               leaf usage {
                 type uint8 {
                    range "0..100";
                 }
                 units "percent";
                 description
                   "The average usage for the duration
                    of the alarm.";
               }
               leaf duration {
                 type uint32;

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                       description
                         "Specify the duration of the first
                          alarm triggered until the feedback
                          information is created.";
                   }
               }
          }
          case disk-alarm {
            container disk-alarm {
              description
                "The container for disk alarm.";
              leaf disk-id {
                type string;
                description
                  "The ID of the storage disk. It is
                   free form identifier to identify
                   the storage disk.";
              }
              leaf usage {
                type uint8 {
                  range "0..100";
                }
                units "percent";
                description
                  "The average usage for the duration
                   of the alarm.";
              }
              leaf duration {
                type uint32;
                description
                  "Specify the duration of the first
                   alarm triggered until the feedback
                   information is created.";
              }
            }
          }
          case interface-alarm {
            container interface-alarm {
              description
                "The container for interface alarm.";
              leaf interface-id {
                type string;
                description
                  "The ID of the network interface. It is
                   a free form identifier to identify
                   the network interface.";
              }
              leaf interface-state {
                type enumeration {

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                   enum up {
                     value 1;
                     description
                       "The interface state is up and
                        not congested. The interface is ready to
                        pass packets.";
                   }
                   enum down {
                     value 2;
                     description
                       "The interface state is down, i.e.,
                       does not pass any packets.";
                   }
                   enum congested {
                     value 3;
                     description
                       "The interface state is up but
                        congested.";
                   }
                   enum testing {
                     value 4;
                     description
                       "In some test mode. No operational
                        packets can be passed.";
                   }
                   enum unknown {
                     value 5;
                     description
                       "Status cannot be determined for
                        some reason.";
                   }
                   enum dormant {
                     value 6;
                     description
                       "Waiting for some external event.";
                   }
                   enum not-present {
                     value 7;
                     description
                       "Some component (typically hardware) is
                        missing.";
                   }
                   enum lower-layer-down {
                     value 8;
                     description
                       "Down due to state of lower-layer
                        interface(s).";
                   }
               }

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                     description
                       "The state of the interface. Applicable
                        for Network Interface Failure Alarm.";
                     reference
                       "RFC 8343: A YANG Data Model for Interface
                        Management- Operational States";
                   }
                   leaf duration {
                     type uint32;
                     description
                       "Specify the duration of the first
                        alarm triggered until the feedback
                        information is created.";
                   }
               }
          }
        }
      }
      container nsf-feedback-information {
        description
          "The output of NSFs will be sent to the I2NSF
           security controller.";
        choice nsf-type {
          description
            "The NSF type.";
          case detection-module {
            container detection-module{
              description
                "The container for the detection
                 module.";
              leaf detection-module-name {
                type string;
                description
                  "The name of the specific
                    detection module.";
              }
              container detected-attacks {
                description
                  "The information of detected attacks.";
                list attack-traffic{
                  key attack-id;
                  description
                  "The five-tuple (src/dst ip, port and
                    protocol) and attack type information
                    of specific attack traffic.";
                  leaf attack-id {
                     type string;
                     description
                     "The ID of the specific attack traffic

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                        which has the same src/dst ip,
                        protocol and attack type.";
                     }
                     leaf attack-type {
                       type string;
                       description
                       "The type of the detected attack.";
                     }
                     leaf attack-src-ip {
                       type inet:ip-address-no-zone;
                       description
                         "The source IPv4 or IPv6 addresses
                          of attack traffic. It can hold
                          multiple IPv4 or IPv6 addresses.";
                     }
                     leaf attack-dst-ip {
                       type inet:ip-address-no-zone;
                       description
                         "The destination IPv4 or IPv6
                          addresses of attack traffic. It can hold
                          multiple IPv4 or IPv6 addresses.";
                     }
                     leaf-list attack-src-port {
                       type inet:port-number;
                       description
                         "The transport-layer source ports
                          of the attack.";
                     }
                     leaf-list attack-dst-port {
                       type inet:port-number;
                       description
                         "The transport-layer destination ports
                          of the attack.";
                     }
                     leaf protocol {
                       type identityref {
                         base protocol;
                       }
                       description
                         "The type of network protocol for
                          the interface counter. If this field
                          is empty, then the counter includes
                          all protocols (e.g., IPv4, IPv6,
                          TCP, and UDP)";
                     }
                     uses attack-rates;
                   }
               }
           }
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         }
        }
      }
    }
    list i2nsf-reconfiguration-policy {
      description
        "The reconfiguration policy generated
         by the I2NSF Analyzer, which will
         be sent to the I2NSF security controller.";
      key name;
      leaf name {
        type string;
        description
          "The name of the reconfiguration policy.";
      }
      choice policy-type {
        case path-reconfiguration-policy{
          container path-reconfiguration-policy{
            description
              "The container for path reconfiguration
                policy.";
            list service-function-path{
              key path-id;
              description
                 "Indicates the NSFs through which
                  traffic passes in sequence.";
              leaf path-id{
                 type string;
                 description
                   "Identify the different service
                     function paths.";
              }
              container nsfs {
                 description
                   "The container for the NSFs in the
                     service function chain (SFC).";
                 list nsf {
                   key nsf-name;
                   description
                      "The container for the NSF.";
                   leaf nsf-name {
                      type string;
                      description
                        "Use the name to identify the NSF.";
                   }
                   leaf sequence-number {
                      type uint64;
                      description
                        "Identifies the sequence of the NSF

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                           in the service function path.";
                         }
                       }
                     }
                   }
               }
           }
       }
     }
   }
   <CODE ENDS>

4.3 The Extended NSF-Facing Interface
   This section describes the Extended NSF-Facing Interface. The
   extension to the interface is the path configuration rule.
   The path configuration rule contains the following information:
   o path-id: Identify the different service function paths.
   o classifier-name: Use the name to identity the classifier.

   o classifier-ip: The IPv4 or IPv6 address of the classifier.

   o nsf-name: Use the name to identify the NSF.

   o sequence-number: Identifies the sequence of the NSF in the
      service function path.

   o nsf-ip: The IPv4 or IPv6 address of the NSF.

   o sff-ip: The IPv4 or IPv6 address of the corresponding SFF.

4.3.1 YANG Tree Structure of Extended NSF-Facing YANG Module

   The tree structure of the Extended NSF-Facing YANG module is
   provided below:
   module: wang-i2nsf-extension-nsf-facing-interface
     +--rw i2nsf-security-policy* [policy-name]
        +--rw policy-name                string
        +--rw path-configuration-rule
           +--rw path-id?       string

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           +--rw classifiers
           | +--rw classifier* [classifier-name]
           |     +--rw classifier-name string
           |     +--rw classifier-ip?     inet:ip-address-no-zone
           +--rw nsfs
              +--rw nsf* [nsf-name]
                 +--rw nsf-name           string
                 +--rw sequence-number?   uint64
                 +--rw ip-address
                    +--rw nsf-ip?   inet:ip-address-no-zone
                    +--rw sff-ip?   inet:ip-address-no-zone
     Figure 4: YANG Tree Structure of Extended NSF-Facing YANG Module

4.3.2 YANG Data Model of Extended NSF-Facing YANG Module

   This section describes a YANG module of I2NSF extended NSF facing
   interface. This YANG module imports from [RFC6991], and makes
   references to [I-D. ietf-i2nsf-nsf-facing-interface-dm].
   <CODE BEGINS> file "wang-i2nsf-extended-nsf-facing-interface@2022-
   09-21.yang"
   module wang-i2nsf-extension-nsf-facing-interface {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:wang-i2nsf-extension-
        nsf-facing-interface";
     prefix i2nsf-exnfi;
     import ietf-inet-types {
       prefix inet;
       reference "RFC 6991";
     }
     organization
       "IETF I2NSF (Interface to Network Security Functions)
        Working Group";
     contact
       "WG Web: <https://datatracker.ietf.org/wg/i2nsf>
        WG List: <mailto:i2nsf@ietf.org>
        Author: Weilin Wang
        <mailto:21111026@bjtu.edu.cn>
        Author: Qi Guo
        <mailto:20120044@bjtu.edu.cn>
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       Author: Shuangxing Deng
       <mailto:21120038@bjtu.edu.cn>";
    description
      "This module is a YANG module for the extension of I2NSF
       NSF-Facing Interface.
       The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
       'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
       'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this
       document are to be interpreted as described in BCP 14
       (RFC 2119) (RFC 8174) when, and only when, they appear
       in all capitals, as shown here.
       Copyright (c) 2022 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 Revised 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
       (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
       for full legal notices.";
    revision "2022-09-19"{
      description "Initial revision.";
      reference
        "RFC XXXX: Extension of I2NSF NSF-Facing Interface
         YANG Data Model";
    }
    list i2nsf-security-policy {
      key policy-name;
      description
        "The container for the security policy.";
      leaf policy-name {
        type string;
        description
          "The name of the security policy.";
      }
      container path-configuration-rule {
        description
          "The container for path configuration rule.";
        leaf path-id {

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          type string;
          description
            "Identify the different service function paths.";
        }
        container classifiers {
          description
            "The container for classifiers in the service
              function chain (SFC).";
          list classifier {
            key classifier-name;
            description
               "The container for the classifier.";
            leaf classifier-name {
               type string;
               description
                 "Use the name to identity the classifier.";
            }
            leaf classifier-ip {
               type inet:ip-address-no-zone;
               description
                 "The IPv4 or IPv6 address of the classifier.";
            }
          }
        }
        container nsfs {
          description
            "The container for the nsfs in the
              service function chain (SFC).";
          list nsf {
            key nsf-name;
            description
               "The container for the NSF.";
            leaf nsf-name {
               type string;
               description
                 "Use the name to identify the NSF.";
            }
            leaf sequence-number {
               type uint64;
               description
                 "Identifies the sequence of the NSF in the
                  service function path.";
            }
            container ip-address {
               description
                 "The IPv4 or IPv6 address of the NSF and
                  the corresponding service function 
                  forwarder (SFF).";
               leaf nsf-ip {
                 description

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                             I2NSF Intelligent Detection        September 2022

                     "The IPv4 or IPv6 address of the NSF.";
                      type inet:ip-address-no-zone;
                }
                leaf sff-ip {
                   description
                       "The IPv4 or IPv6 address of the
                         corresponding SFF.";
                    type inet:ip-address-no-zone;
                 }
                }
              }
           }
       }
     }
   }
   <CODE ENDS>

5. XML Examples of I2NSF Framework for AID
   This section shows XML examples for the DDoS attacks [Two-Stage
   Intelligent Model for Detecting Malicious DDoS Behavior] intelligent
   detection, including XMLs of traffic flow features, path
   reconfiguration policy and path configuration rules. Refer to
   [RFC5277] for more detailed explanation of Event Streams. The XML
   examples in this document follow the line breaks as per [RFC8792].
                        +----------------------------------------------+
                        | Secure Network                               |
                        | CF/SFF:192.168.14.0/24,DDoS-DM:172.17.0.0/16 |
                        |         +-------------------------+          |
   +-------------+      | +---+   | +---------+             |  +---+   |
   |DDoS Attacker|      | |CF1|-->| |SFF1     |             |->|CF2|   |
   |23.1.0.22,   |DDoS  | +---+   | |DDoS-DM-1| +---------+ |  +---+   |
   |23.1.0.23,   +----->|         | +---------+ |SFF3     | |    |     |
   |23.1.0.24    |Attack|         | +---------+ |DDoS-DM-3| |    |     |
   +-------------+      |         | |SFF2     | |DDoS-DM-5| |    v     |
                        |         | |DDoS-DM-2| +---------+ | +------+ |
                        |         | |DDoS-DM-4|             | |Server| |
                        |         | +---------+             | +------+ |
                        |         +-------------------------+          |
                        +----------------------------------------------+
                       Figure 5: A Scenario Example of a DDoS Attack
   In this example, the scenario can be seen in Figure 5. This example
   contains five DDoS DMs to detect different types of DDoS attacks.
   The system presets an SFC path, path1= {DDoS-DM-2,
   DDoS-DM-1, DDoS-DM-4, DDoS-DM-3}.

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  The entrance classifier (CF1) feeds back traffic features to the
  I2NSF Analyzer through the Extended Monitoring Interface. The
  following XML file shows the feedback traffic flow features:
  <?xml version="1.0" encoding="UTF-8"?>
  <notification
    xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
      <eventTime>2022-09-20T11:28:01.00Z</eventTime>
      <i2nsf-event
        xmlns="urn:ietf:params:xml:ns:yang:wang-i2nsf-extended-
  monitoring-interface">
        <nsf-name>CF1</nsf-name>
        <acquisition-method>subscription</acquisition-method>
        <emission-type>on-change</emission-type>
        <dampening-type>on-repetition</dampening-type>
        <i2nsf-traffic-flow-features>
          <measurement-time>5</measurement-time>
          <packets-per-second>400.18</packets-per-second>
          <bytes-per-second>450643.1</bytes-per-second>
          <packet-size-mean>1126.1</packet-size-mean>
          <src-ip-entropy>3.27</src-ip-entropy>
          <dst-ip-entropy>1.71</dst-ip-entropy>
          <TTL-entropy>3.17</TTL-entropy>
          <tcp-src-port-entropy>5.34</tcp-src-port-entropy>
          <tcp-dst-port-entropy>4.44</tcp-dst-port-entropy>
          <udp-src-port-entropy>5.02</udp-src-port-entropy>
          <udp-dst-port-entropy>5.02</udp-dst-port-entropy>
          <packet-size-entropy>2.5</packet-size-entropy>
          <packets-variance>0</packets-variance>
        </i2nsf-traffic-flow-features>
    </i2nsf-event>
  </notification>
            Figure 6: The Feedback Traffic Flow Features by CF1
  The XML file in Figure6 shows:
  o   The NSF that sends the information is named "CF1".
  o   The monitoring information is received by subscription method.

  o   The monitoring information is emitted "on-change".

  o   The monitoring information is dampened "on-repetition".

  o   The measurement time is 5s.

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  o   The packets per second is 400.18.

  o   The bytes per second is 450643.1.

  o   The packet size mean is 1126.1.

  o   The source IP entropy is 3.27.

  o   The destination IP entropy is 1.71.

  o   The TTL entropy is 3.17.

  o   The TCP source port entropy is 5.34.

  o   The TCP destination port entropy is 4.44.

  o   The UDP source port entropy is 5.02.

  o   The UDP destination port entropy is 5.02.

  o   The packet size entropy is 2.5.

  o   The packets variance is 0.
  I2NSF Analyzer analyzes traffic features and generates path
  reconfiguration policies for the current traffic. The policy is sent
  to the Security Controller through the Extended Analytics Interface.
  The following XML file shows the path reconfiguration policy:
  <?xml version="1.0" encoding="UTF-8"?>
  <i2nsf-reconfiguration-policy
    xmlns="urn:ietf:params:xml:ns:yang:wang-i2nsf-extension-analytics-
  interface">
      <name>detection-path-reconfiguration-policy</name>
      <path-reconfiguration-policy>
        <service-function-path>
          <path-id>path2</path-id>
          <nsfs>
            <nsf>
              <nsf-name>DDoS-DM-5</nsf-name>
              <sequence-number>1</sequence-number>
            </nsf>
            <nsf>
              <nsf-name>DDoS-DM-3</nsf-name>
              <sequence-number>2</sequence-number>
            </nsf>
            <nsf>

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                     I2NSF Intelligent Detection        September 2022

              <nsf-name>DDoS-DM-4</nsf-name>
              <sequence-number>3</sequence-number>
            </nsf>
          </nsfs>
        </service-function-path>
      </path-reconfiguration-policy>
  </i2nsf-reconfiguration-policy>
  Figure 7: The Path Reconfiguration Policy Generated by I2NSF Analyzer
  The XML file in Figure7 shows:
  o   The policy name is "detection-path-reconfiguration-policy".
  o   The path ID is "path2".

  o   The NSFs in the path are named "DDoS-DM-5", "DDoS-DM-3" and
      "DDoS-DM-4". Their sequence numbers are "1", "2" and "3" 
       respectively.
  The Security Controller translates this policy into path
  configuration rules and sends these rules to the SDN Controller
  through the Extended NSF-Facing Interface. The following XML file
  shows the path configuration rules for SDN Controller:
  <?xml version="1.0" encoding="UTF-8"?>
  <i2nsf-security-policy
    xmlns="urn:ietf:params:xml:ns:yang:wang-i2nsf-extension-nsf-facing-
  interface">
    <policy-name>detection-path-reconfiguration-policy</policy-name>
    <path-configuration-rule>
      <path-id>path2</path-id>
      <classifiers>
        <classifier>
          <classifier-name>CF1</classifier-name>
          <classifier-ip>192.168.14.7</classifier-ip>
        </classifier>
        <classifier>
          <classifier-name>CF2</classifier-name>
          <classifier-ip>192.168.14.8</classifier-ip>
        </classifier>
      </classifiers>
      <nsfs>
        <nsf>
          <nsf-name>DDoS-DM-5</nsf-name>
          <sequence-number>1</sequence-number>
          <ip-address>
             <nsf-ip>172.17.23.2</nsf-ip>
             <sff-ip>192.168.14.23</sff-ip>

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                      I2NSF Intelligent Detection       September 2022
            </ip-address>
          </nsf>
          <nsf>
            <nsf-name>DDoS-DM-3</nsf-name>
            <sequence-number>2</sequence-number>
            <ip-address>
              <nsf-ip>172.17.23.3</nsf-ip>
              <sff-ip>192.168.14.23</sff-ip>
            </ip-address>
          </nsf>
          <nsf>
            <nsf-name>DDoS-DM-4</nsf-name>
            <sequence-number>3</sequence-number>
            <ip-address>
              <nsf-ip>172.17.24.2</nsf-ip>
              <sff-ip>192.168.14.24</sff-ip>
            </ip-address>
          </nsf>
        </nsfs>
      </path-configuration-rule>
         Figure 8: The Path Configuration Rules for SDN Controller
  The XML file in Figure8 shows:
  o   The policy name is "detection-path-reconfiguration-policy".
  o   The path ID is "path2".

  o   The classifiers in the path are named "CF1" and "CF2". Their IP
      addresses are "192.168.14.7" and "192.168.14.8" respectively.

  o   The first NSF in the path is named "DDoS-DM-5". Its IP address is
      "172.17.23.2", and its corresponding SFF IP address is
      "192.168.14.23".

  o   The second NSF in the path is named "DDoS-DM-3". Its IP address
      is "172.17.23.3", and its corresponding SFF IP address is
      "192.168.14.23".

  o   The third NSF in the path is named "DDoS-DM-4". Its IP address is
      "172.17.24.2", and its corresponding SFF IP address is
      "192.168.14.24".
  The SDN Controller generates flow tables according to the path
  configuration rules and sends them to CFs and SFFs to make the
  traffic pass the new detection path, path2= {DDoS-DM-5, DDoS-DM-3,
  DDoS-DM-4}. Through three extended interfaces, I2NSF Analyzer and

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                         I2NSF Intelligent Detection    September 2022

   Security Controller realize dynamic automatic adjustment of DDoS
   attack detection path policy based on the closed-loop feedback.

6. IANA Considerations
   This document has no IANA actions

7. Security Considerations
   The YANG module specified in this document defines a data schema
   designed to be accessed through network management protocols such as
   NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is
   the secure transport layer, and the required secure transport is
   Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS,
   and the required secure transport is TLS [RFC8446].
   The NETCONF access control model [RFC8341] provides a means of
   restricting access to specific 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/delectable (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. The data models in this document uses the data
   model from NSF Monitoring data model, Analytics Interface YANG data
   model and NSF-Facing Interface data model, they MUST follow the
   Security Considerations mentioned in [I-D. ietf-i2nsf-nsf-monitoring-
   data-model], [I-D. lingga-i2nsf-analytics-interface-dm] and [I-D.
   ietf-i2nsf-nsf-facing-interface-dm].
   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments. Thus, it is
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes. This document MUST also follow the
   Security Considerations about the readable data nodes mentioned in
   [I-D. ietf-i2nsf-nsf-monitoring-data-model], [I-D. lingga-i2nsf-
   analytics-interface-dm] and [I-D. ietf-i2nsf-nsf-facing-interface-
   dm].

8. References
8.1 Normative References

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                     I2NSF Intelligent Detection       September 2022

   [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, DOI
             10.17487/RFC0768, August 1980, <https://www.rfc-
             editor.org/info/rfc768>.
   [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, DOI
             10.17487/RFC0791, September 1981, <https://www.rfc-
             editor.org/info/rfc791>.
   [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
             RFC 792, DOI 10.17487/RFC0792, September 1981,
             <https://www.rfc-editor.org/info/rfc792>.
   [RFC0854] Postel, J. and J. Reynolds, "Telnet Protocol
             Specification", STD 8, RFC 854, DOI 10.17487/RFC0854, May
             1983, <https://www.rfc-editor.org/info/rfc854>.
   [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", STD
             9, RFC 959, DOI 10.17487/RFC0959, October 1985,
             <https://www.rfc-editor.org/info/rfc959>.
   [RFC1939] Myers, J. and M. Rose, "Post Office Protocol - Version 3",
             STD 53, RFC 1939, DOI 10.17487/RFC1939, May 1996,
             <https://www.rfc-editor.org/info/rfc1939>.
   [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>.
   [RFC2595] Newman, C., "Using TLS with IMAP, POP3 and ACAP", RFC 2595,
             DOI 10.17487/RFC2595, June 1999, <https://www.rfc-
             editor.org/info/rfc2595>.
   [RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
             Congestion Control Protocol (DCCP)", RFC 4340, DOI
             10.17487/RFC4340, March 2006,<https://www.rfc-
             editor.org/info/rfc4340>.
   [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
             Control Message Protocol (ICMPv6) for the Internet
             Protocol Version 6 (IPv6) Specification", STD 89, RFC 4443,
             DOI 10.17487/RFC4443, March 2006, <https://www.rfc-
             editor.org/info/rfc4443>.
   [RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event Notifications",
             RFC 5277, DOI 10.17487/RFC5277, July 2008,
             <https://www.rfc-editor.org/info/rfc5277>.

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                     I2NSF Intelligent Detection       September 2022

   [RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
             DOI 10.17487/RFC5321, October 2008, <https://www.rfc-
             editor.org/info/rfc5321>.
   [RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
             Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
             September 2009, <https://www.rfc-editor.org/info/rfc5646>.
   [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
             Network Configuration Protocol (NETCONF)", RFC 6020,
             October 2010, <https://www.rfc-editor.org/info/rfc6020>.
   [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>.
   [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>.
   [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991,
             DOI 10.17487/RFC6991, July 2013, <https://www.rfc-
             editor.org/info/rfc6991>.
   [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>.
   [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
             2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
             May 2017, <https://www.rfc-editor.org/info/rfc8174>.
   [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
             (IPv6) Specification", STD 86, RFC 8200, DOI
             10.17487/RFC8200, July 2017, <https://www.rfc-
             editor.org/info/rfc8200>.
   [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
             Access Control Model", RFC 8341, DOI 10.17487/RFC8341, STD
             91, March 2018, <https://www.rfc-editor.org/info/rfc8341>.
   [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>.
   [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>.

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                     I2NSF Intelligent Detection       September 2022

   [RFC9051] Melnikov, A., Ed. and B. Leiba, Ed., "Internet
             MessageAccess Protocol (IMAP) - Version 4rev2", RFC 9051,
             DOI 10.17487/RFC9051, August 2021, <https://www.rfc-
             editor.org/info/rfc9051>.
   [RFC9110] R. Fielding, M. Nottingham and J. Reschke, "HTTP
             Semantics", RFC9110, DOI 10.17487/RFC9110, June 2022,
             <https://www.rfc-editor.org/info/rfc9110>.
   [RFC9112] Fielding, R. T., Nottingham, M., and J. Reschke,
             "HTTP/1.1", RFC9112, DOI 10.17487/RFC9112, June 2022,
             <https://www.rfc-editor.org/info/rfc9112>.

   [RFC9113] Thomson, M. and C. Benfield, "HTTP/2", RFC9113, DOI
             10.17487/RFC9113, June 2022, <https://www.rfc-
             editor.org/info/rfc9113>.
   [RFC9260] R. Stewart, M. Tüxen and K. Nielsen, "Stream Control
             Transmission Protocol", DOI 10.17487/RFC9260, June 2022,
             <https://www.rfc-editor.org/info/rfc9260>.
   [RFC9293] W. Eddy, "Transmission Control Protocol (TCP)", DOI
             10.17487/RFC9293, August 2022, <https://www.rfc-
             editor.org/info/rfc9293>.
  [I-D. lingga-i2nsf-analytics-interface-dm]
         P. Lingga, Ed., J. Jeong, Ed. and Y. Choi, "I2NSF Analytics
         Interface YANG Data Model", Work in Progress, Internet-Draft,
         draft-lingga-i2nsf-analytics-interface-dm-00, 25 July 2022, <
         https://www.ietf.org/archive/id/draft-lingga-i2nsf-analytics-
         interface-dm-00.txt>.
  [I-D. ietf-i2nsf-applicability]
         Jeong, J. P., Hyun, S., Ahn, T., Hares, S., and D. R. Lopez,
         "Applicability of Interfaces to Network Security Functions to
         Network-Based Security Services", Work in Progress, Internet-
         Draft, draft-ietf-i2nsf-applicability-18, 16 September 2019,
         <https://www.ietf.org/archive/id/draft-ietf-i2nsf-
         applicability-18.txt>.
  [I-D. ietf-i2nsf-nsf-facing-interface-dm]
         Kim, J. T., Jeong, J. P., Park, J., Hares, S., and Q. Lin,
         "I2NSF Network Security Function-Facing Interface YANG Data
         Model", Work in Progress, Internet-Draft, draft-ietfi2nsf-nsf-
         facing-interface-dm-29, 1 June 2022,
         <https://www.ietf.org/archive/id/draft-ietf-i2nsf-nsffacing-
         interface-dm-29.txt>.

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                     I2NSF Intelligent Detection        September 2022

   [I-D. ietf-i2nsf-nsf-monitoring-data-model]
          Jeong, J. P., Lingga, P., Hares, S., Xia, L. F., and H.
          Birkholz, "I2NSF NSF Monitoring Interface YANG Data Model",
          Work in Progress, Internet-Draft, draft-ietfi2nsf-nsf-
          monitoring-data-model-20, 1 June 2022,
          <https://www.ietf.org/archive/id/draft-ietf-i2nsf-
          nsfmonitoring-data-model-20.txt>.
   [I-D. jeong-i2nsf-security-management-automation]
          Jeong, J. (., Lingga, P., and J. Park, "An Extension of I2NSF
          Framework for Security Management Automation in Cloud-Based
          Security Services", Work in Progress, Internet-Draft, draft-
          jeong-i2nsf-security-managementautomation-04, 25 July 2022,
          <https://www.ietf.org/archive/id/draft-jeong-i2nsfsecurity-
          management-automation-04.txt>.
   [ITU-TY.3300]
          International Telecommunications Union "Y.3300: Framework of
          software defined networking", June 2014,
          <https://www.itu.int/rec/T-REC-Y.3300/en>.

8.2 Informative References
   [RFC7665] Halpern, J. and C. Pignataro, "Service Function Chaining
             (SFC) Architecture", RFC 7665, October 2015,
             <https://www.rfc-editor.org/info/rfc7665>.
   [RFC8192] Hares, S. Lopez, D. Zarny, M. Jacquenet, C. Kumar, R. and
             J. Jeong "Interface to Network Security Functions (I2NSF):
             Problem Statement and Use Cases" RFC8192 DOI
             10.17487/RFC8192 <https://www.rfc-editor.org/info/rfc8192>.
   [RFC8329] Lopez, D. Lopez, E. Dunbar, L. Strassner, J. R. Kumar
             "Framework for Interface to Network Security Functions",
             RFC 8329, DOI 10.17487/RFC8329, <https://www.rfc-
             editor.org/info/rfc8329>.
   [RFC8455] V. Bhuvaneswaran, A. Basil, M. Tassinari, V. Manral and S.
             Banks, "Terminology for Benchmarking Software-Defined
             Networking (SDN) Controller Performance", RFC8455, DOI
             10.17487/RFC8455, <https://www.rfc-
             editor.org/info/rfc8455>.
   [RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
             "Handling Long Lines in Content of Internet-Drafts and
             RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
             <https://www.rfc-editor.org/info/rfc8792>.

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  [Two-Stage Intelligent Model for Detecting Malicious DDoS Behavior]
         Li, M.; Zhou, H.; Qin, Y. Two-Stage Intelligent Model for
         Detecting Malicious DDoS Behavior. Sensors 2022, 22, 2532.
         https:// doi.org/10.3390/s22072532

Acknowledgments
  TBC

Author's Addresses
  Weilin Wang
  Beijing Jiaotong University
  Beijing
  Phone: <86-15910887582>
  Email: 21111026@bjtu.edu.cn
  Huachun Zhou
  Beijing Jiaotong University
  Beijing
  Phone: <86-13718168186>
  Email: hchzhou@bjtu.edu.cn
  Man Li
  Beijing Jiaotong University
  Beijing
  Phone: <86-18810911698>
  Email: 20111018@bjtu.edu.cn
  Qi Guo
  Beijing Jiaotong University
  Beijing
  Phone: <86-18310379269>
  Email: 20120044@bjtu.edu.cn
  Shuangxing Deng
  Beijing Jiaotong University
  Beijing
  Phone: <86-13040062046>
  Email: 21120038@bjtu.edu.cn

Wang, et al.           Expires – February 2023               [Page 59]