I2NSF Working Group                                        J. Jeong, Ed.
Internet-Draft                                                  C. Chung
Intended status: Standards Track                 Sungkyunkwan University
Expires: 19 November 2022                                         T. Ahn
                                                           Korea Telecom
                                                                R. Kumar
                                                        Juniper Networks
                                                                S. Hares
                                                                  Huawei
                                                             18 May 2022


            I2NSF Consumer-Facing Interface YANG Data Model
            draft-ietf-i2nsf-consumer-facing-interface-dm-19

Abstract

   This document describes an information model and the corresponding
   YANG data model for the Consumer-Facing Interface of the Security
   Controller in an Interface to Network Security Functions (I2NSF)
   system in a Network Functions Virtualization (NFV) environment.  The
   information model defines various types of managed objects and the
   relationship among them needed to build the flow policies from users'
   perspective.  This information model is based on the "Event-
   Condition-Action" (ECA) policy model defined by a capability
   information model for I2NSF, and the YANG data model is defined for
   enabling different users of a given I2NSF system to define, manage,
   and monitor flow policies within an administrative domain.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 19 November 2022.






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Copyright Notice

   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Information Model for Policy  . . . . . . . . . . . . . . . .   5
     3.1.  Event Sub-model . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  Condition Sub-model . . . . . . . . . . . . . . . . . . .   7
     3.3.  Action Sub-model  . . . . . . . . . . . . . . . . . . . .  10
   4.  Information Model for Policy Endpoint Groups  . . . . . . . .  11
     4.1.  User Group  . . . . . . . . . . . . . . . . . . . . . . .  12
     4.2.  Device Group  . . . . . . . . . . . . . . . . . . . . . .  12
     4.3.  Location Group  . . . . . . . . . . . . . . . . . . . . .  13
     4.4.  URL Group . . . . . . . . . . . . . . . . . . . . . . . .  14
   5.  Information Model for Threat Prevention . . . . . . . . . . .  14
     5.1.  Threat Feed . . . . . . . . . . . . . . . . . . . . . . .  15
     5.2.  Payload Content . . . . . . . . . . . . . . . . . . . . .  16
   6.  Network Configuration Access Control Model (NACM) for I2NSF
           Consumer-Facing Interface . . . . . . . . . . . . . . . .  16
   7.  YANG Data Model of Consumer-Facing Interface  . . . . . . . .  19
     7.1.  YANG Module of Consumer-Facing Interface  . . . . . . . .  19
   8.  XML Configuration Examples of High-Level Security Policy
           Rules . . . . . . . . . . . . . . . . . . . . . . . . . .  56
     8.1.  Database Registration: Information of Positions and Devices
           (Endpoint Group)  . . . . . . . . . . . . . . . . . . . .  57
     8.2.  Scenario 1: Block SNS Access during Business Hours  . . .  58
     8.3.  Scenario 2: Block Malicious VoIP/VoCN Packets Coming to a
           Company . . . . . . . . . . . . . . . . . . . . . . . . .  60
     8.4.  Scenario 3: Mitigate Flood Attacks on a Company Web
           Server  . . . . . . . . . . . . . . . . . . . . . . . . .  61
   9.  XML Configuration Example of a User Group's Access Control for
           I2NSF Consumer-Facing Interface . . . . . . . . . . . . .  63
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  64
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  65
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  66



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     12.1.  Normative References . . . . . . . . . . . . . . . . . .  66
     12.2.  Informative References . . . . . . . . . . . . . . . . .  70
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  71
   Appendix B.  Contributors . . . . . . . . . . . . . . . . . . . .  71
   Appendix C.  Changes from
           draft-ietf-i2nsf-consumer-facing-interface-dm-18  . . . .  72
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  73

1.  Introduction

   In a framework of Interface to Network Security Functions (I2NSF)
   [RFC8329], each vendor can register their NSFs using a Developer's
   Management System (DMS).  Assuming that vendors also provide the
   front-end web applications to an I2NSF User, the Consumer-Facing
   Interface is required because the web applications developed by each
   vendor need to have a standard interface specifying the data types
   used when the I2NSF User and Security Controller communicate with
   each other using this interface.  Therefore, this document specifies
   the required information, their data types, and encoding schemes so
   that high-level security policies (or configuration information for
   security policies) can be transferred to the Security Controller
   through the Consumer-Facing Interface.  These policies can easily be
   translated by the Security Controller into low-level security
   policies.  The Security Controller delivers the translated policies
   to Network Security Functions (NSFs) according to their respective
   security capabilities for the required security enforcement.

   The Consumer-Facing Interface would be built using a set of objects,
   with each object capturing a unique set of information from Security
   Administrator (i.e., I2NSF User [RFC8329]) needed to express a
   Security Policy.  An object may have relationship with various other
   objects to express a complete set of requirements.  An information
   model captures the managed objects and relationship among these
   objects.  The information model proposed in this document is
   structured in accordance with the "Event-Condition-Action" (ECA)
   policy model.

   An NSF Capability model is proposed in
   [I-D.ietf-i2nsf-capability-data-model] as the basic model for both
   the NSF-Facing interface and Consumer-Facing Interface security
   policy model of this document.










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   [RFC3444] explains differences between an information and data model.
   This document uses the guidelines in [RFC3444] to define both the
   information and data model for Consumer-Facing Interface.  Figure 1
   shows a high-level abstraction of Consumer-Facing Interface.  A data
   model, which represents an implementation of the information model in
   a specific data representation language, is also defined in this
   document.

                       +-----------------+
                       | Consumer-Facing |
                       |    Interface    |
                       +--------+--------+
                                ^
                                |
                                +-------------+------------+
                                |             |            |
                          +-----+----+  +-----+----+  +----+---+
                          |  Policy  |  | Endpoint |  | Threat |
                          |          |  |  groups  |  |  feed  |
                          +-----+----+  +----------+  +--------+
                                ^
                                |
                         +------+------+
                         |     Rule    |
                         +------+------+
                                ^
                                |
               +----------------+----------------+
               |                |                |
        +------+------+  +------+------+  +------+------+
        |    Event    |  |  Condition  |  |    Action   |
        +-------------+  +-------------+  +-------------+


      Figure 1: Diagram for High-level Abstraction of Consumer-Facing
                                 Interface

   Data models are defined at a lower level of abstraction and provide
   many details.  They provide details about the implementation of a
   protocol's specification, e.g., rules that explain how to map managed
   objects onto lower-level protocol constructs.  Since conceptual
   models can be implemented in different ways, multiple data models can
   be derived from a single information model.

   The efficient and flexible provisioning of network functions by a
   Network Functions Virtualization (NFV) system leads to a rapid
   advance in the network industry.  As practical applications, Network
   Security Functions (NSFs), such as firewall, Intrusion Detection



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   System (IDS)/Intrusion Prevention System (IPS), and attack
   mitigation, can also be provided as Virtual Network Functions (VNF)
   in the NFV system.  By the efficient virtualization technology, these
   VNFs might be automatically provisioned and dynamically migrated
   based on real-time security requirements.  This document presents a
   YANG data model to implement security functions based on NFV.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   This document uses the terminology described in [RFC8329].

   This document follows the guidelines of [RFC8407], uses the common
   YANG types defined in [RFC6991], and adopts the Network Management
   Datastore Architecture (NMDA) [RFC8342].  The meaning of the symbols
   in tree diagrams is defined in [RFC8340].

3.  Information Model for Policy

   A Policy object represents a mechanism to express a Security Policy
   by Security Administrator (i.e., I2NSF User) using Consumer-Facing
   Interface toward Security Controller; the policy would be enforced on
   an NSF.  Figure 2 shows the YANG tree of the Policy object.  The
   Policy object SHALL have the following information:

   Name:     This field identifies the name of this object.

   Language:  The language field indicates the language tag that is used
             for the natural language text that is included in all of
             the 'description' attributes.  The language field is
             encoded following the rules in Section 2.1 of [RFC5646].
             The default language tag is "en-US".

   Resolution-strategy:  This field represents how to resolve conflicts
             that occur between actions of the same or different policy
             rules that are matched and contained in this particular
             NSF.  The resolution strategy is described in
             [I-D.ietf-i2nsf-capability-data-model] in detail.

   Rules:    This field contains a list of rules.  These rules are
             defined for 1) communication between two Endpoint Groups,
             2) for preventing communication with externally or
             internally identified threats, and 3) for implementing



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             business requirement such as controlling access to internal
             or external resources for meeting regulatory compliance or
             business objectives.  An organization may restrict certain
             communication between a set of user and applications for
             example.  The threats may be from threat feeds obtained
             from external sources or dynamically identified by using
             specialty devices in the network.  Rule conflict analysis
             should be triggered by the monitoring service to perform an
             exhaustive detection of anomalies among the configuration
             rules installed into the security functions.


   module: ietf-i2nsf-cfi-policy
     +--rw i2nsf-cfi-policy* [name]
        +--rw name                   string
        +--rw language?              string
        +--rw resolution-strategy?   identityref
        +--rw rules* [name]
        |  ...
        +--rw endpoint-groups
        |  ...
        +--rw threat-prevention
           ...


                      Figure 2: Policy YANG Data Tree

   A policy is a list of rules.  In order to express a Rule, a Rule must
   have complete information such as where and when a policy needs to be
   applied.  This is done by defining a set of managed objects and
   relationship among them.  A Policy Rule may be related segmentation,
   threat mitigation or telemetry data collection from an NSF in the
   network, which will be specified as the sub-model of the policy model
   in the subsequent sections.  Figure 3 shows the YANG data tree of the
   Rule object.  The rule object SHALL have the following information:

   Name:     This field identifies the name of this object.

   Priority:  This field identifies the priority of the rule.

   Event:    This field includes the information to determine whether
             the Rule Condition can be evaluated or not.  See details in
             Section 3.1.

   Condition:  This field contains all the checking conditions to apply
             to the objective traffic.  See details Section 3.2.

   Action:   This field identifies the action taken when a rule is



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             matched.  There is always an implicit action to drop
             traffic if no rule is matched for a traffic type.  See
             details in Section 3.3.


        +--rw rules* [name]
        |  +--rw name         string
        |  +--rw priority?    uint8
        |  +--rw event
        |  |  ...
        |  +--rw condition
        |  |  ...
        |  +--rw action
        |     ...


                       Figure 3: Rule YANG Data Tree

3.1.  Event Sub-model

   The Event Object contains information related to scheduling a Rule.
   The Rule could be activated based on a security event (i.e., system
   event and system alarm).  Figure 4 shows the YANG tree of the Event
   object.  Event object SHALL have following information:

   System-event (also called alert):  is defined as a warning about any
             changes of configuration, any access violation, the
             information of sessions and traffic flows.

   System-alarm:  is defined as a warning related to service degradation
             in system hardware.

        |  +--rw event
        |  |  +--rw system-event*   identityref
        |  |  +--rw system-alarm*   identityref


                  Figure 4: Event Sub-model YANG Data Tree

3.2.  Condition Sub-model

   This object represents Conditions that Security Administrator wants
   to apply the checking on the traffic in order to determine whether
   the set of actions in the Rule can be executed or not.  The Condition
   Sub-model consists of three different types of containers each
   representing different cases, such as general firewall and DDoS-
   mitigation cases, and a case when the condition is based on the
   payload strings of packets.  Each containers have source and



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   destination-target to represent the source and destination for each
   case.  Figure 5 shows the YANG tree of the Condition object.  The
   Condition Sub-model SHALL have following information:

   Case (firewall):  This field represents the general firewall case,
             where a security admin can set up firewall conditions using
             the information present in this field.  The firewall
             attributes are represented by source, destination,
             transport layer protocol, port numbers, and ICMP
             parameters.  Note that the YANG module only provide high-
             level ICMP messages that is shared between ICMPv4 and
             ICMPv6 (e.g., Destination Unreachable: Port Unreachable
             which is ICMPv4 type 3 code 3 or ICMPv6 type 1 code 4).
             Also note that QUIC protocol [RFC9000] is excluded in the
             data model as it is not considered in the initial I2NSF
             documents [RFC8329].  The QUIC traffic should not be
             treated as UDP traffic and will be considered in the future
             I2NSF documents.

   Case (ddos):  This field represents the condition for DDoS
             mitigation, where a security admin can set up DDoS
             mitigation conditions using the information present in this
             field.  The rate of packet, byte, or flow threshold can be
             configured to mitigate the DDoS.

   Case (anti-virus):  This field represents the condition for
             Antivirus, where a security admin can set up Antivirus
             conditions using the information present in this field.
             The file names or types can be configured to be allowed
             without the Antivirus interuption.

   Case (payload):  This field contains the payload string information.
             This information is useful when security rule condition is
             based on the string contents of incoming or outgoing
             packets.  The name referring to the payload-groups defined
             and registered in the endpoint-groups.

   Case (url-category):  This field represents the URL to be filtered.
             This information can be used to block or allow a certain
             URL or website.  The url-name is a group of URL or websites
             to be matched.

   Case (voice):  This field contains the call source-id, call
             destination-id, and user-agent.  This information can be
             used to filter a caller id or receiver id to prevent any
             VoIP or VoCN exploits or attack.

   Case (context):  This field provide extra information for the



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             condition for filtering the network traffic.  The given
             context conditions are application filter, device type,
             user condition, and geographic location.

   Case (Threat-feed):  This field contains the information obtained
             from threat-feeds (e.g., Palo-Alto, or RSA-netwitness).
             This information is useful when security rule condition is
             based on the existing threat reports gathered by other
             sources.

   |  +--rw condition
   |  |  +--rw firewall
   |  |  |  +--rw source*                     union
   |  |  |  +--rw destination*                union
   |  |  |  +--rw transport-layer-protocol?   identityref
   |  |  |  +--rw range-port-number
   |  |  |  |  +--rw start-port-number?   inet:port-number
   |  |  |  |  +--rw end-port-number?     inet:port-number
   |  |  |  +--rw icmp
   |  |  |     +--rw message*   identityref
   |  |  +--rw ddos
   |  |  |  +--rw rate-limit
   |  |  |     +--rw packet-rate-threshold?   uint64
   |  |  |     +--rw byte-rate-threshold?     uint64
   |  |  |     +--rw flow-rate-threshold?     uint64
   |  |  +--rw anti-virus
   |  |  |  +--rw exception-files*   string
   |  |  +--rw payload
   |  |  |  +--rw content*
             -> /i2nsf-cfi-policy/threat-prevention/payload-content/name
   |  |  +--rw url-category
   |  |  |  +--rw url-name?
                     -> /i2nsf-cfi-policy/endpoint-groups/url-group/name
   |  |  +--rw voice
   |  |  |  +--rw source-id*        string
   |  |  |  +--rw destination-id*   string
   |  |  |  +--rw user-agent*       string
   |  |  +--rw context
   |  |  |  +--rw time
   |  |  |  |  +--rw start-date-time?   yang:date-and-time
   |  |  |  |  +--rw end-date-time?     yang:date-and-time
   |  |  |  |  +--rw period
   |  |  |  |  |  +--rw start-time?   time
   |  |  |  |  |  +--rw end-time?     time
   |  |  |  |  |  +--rw day*          day
   |  |  |  |  |  +--rw date*         int32
   |  |  |  |  |  +--rw month*        string
   |  |  |  |  +--rw frequency?         enumeration



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   |  |  |  +--rw application
   |  |  |  |  +--rw protocol*      identityref
   |  |  |  +--rw device-type
   |  |  |  |  +--rw device*        identityref
   |  |  |  +--rw users
   |  |  |  |  +--rw user* [id]
   |  |  |  |  |  +--rw id      uint32
   |  |  |  |  |  +--rw name?   string
   |  |  |  |  +--rw group* [id]
   |  |  |  |     +--rw id      uint32
   |  |  |  |     +--rw name?   string
   |  |  |  +--rw geographic-location
   |  |  |     +--rw source*
                -> /i2nsf-cfi-policy/endpoint-groups/location-group/name
   |  |  |     +--rw destination*
                -> /i2nsf-cfi-policy/endpoint-groups/location-group/name
   |  |  +--rw threat-feed
   |  |     +--rw name*
           -> /i2nsf-cfi-policy/threat-prevention/threat-feed-list/name


                Figure 5: Condition Sub-model YANG Data Tree

3.3.  Action Sub-model

   This object represents actions that Security Admin wants to perform
   based on certain traffic class.  Figure 6 shows the YANG tree of the
   Action object.  The Action object SHALL have following information:

   Primary-action:  This field identifies the action when a rule is
             matched by an NSF.  The action could be one of "pass",
             "drop", "reject", "rate-limit", "mirror", "invoke-
             signaling", "tunnel-encapsulation", "forwarding", and
             "transformation".

   Secondary-action:  This field identifies the action when a rule is
             matched by an NSF.  The action could be one of "rule-log"
             and "session-log".

        +--rw action
        |  +--rw primary-action
        |  |  +--rw action?   identityref
        |  +--rw secondary-action
        |     +--rw log-action?   identityref


                 Figure 6: Action Sub-model YANG Data Tree




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4.  Information Model for Policy Endpoint Groups

   The Policy Endpoint Group is a very important part of building User-
   Construct based policies.  A Security Administrator would create and
   use these objects to represent a logical entity in their business
   environment, where a Security Policy is to be applied.  There are
   multiple managed objects that constitute a Policy's Endpoint Group,
   as shown in Figure 7.  Figure 8 shows the YANG tree of the Endpoint-
   Groups object.  This section lists these objects and relationship
   among them.

   It is assumed that the information of Endpoint Groups (e.g., User-
   group, Device-group, and Location-group) such as the IP address(es)
   of each member in a group are stored in the I2NSF database available
   to the Security Controller, and that the IP address information of
   each group in the I2NSF database is synchronized with other systems
   in the networks under the same administration.

                        +-------------------+
                        |  Endpoint Groups  |
                        +---------+---------+
                                  ^
                                  |
           +--------------+-------+--------+---------------+
    0..n   |      0..n    |       0..n     |          0..n |
     +-----+----+  +------+-----+  +-------+------+  +-----+---+
     |User-group|  |Device-group|  |Location-group|  |Url-group|
     +----------+  +------------+  +--------------+  +---------+


                      Figure 7: Endpoint Group Diagram

     +--rw endpoint-groups
     |  +--rw user-group* [name]
     |  ...
     |  +--rw device-group* [name]
     |  ...
     |  +--rw location-group* [name]
     |  ...
     |  +--rw url-group* [name]
     |  ...


                  Figure 8: Endpoint Group YANG Data Tree







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4.1.  User Group

   This object represents a User-Group.  Figure 9 shows the YANG tree of
   the User-Group object.  The User-Group object SHALL have the
   following information:

   Name:     This field identifies the name of this object.

   mac-address:  This represents the MAC address of a user in the user
             group.

   Range-ipv4-address:  This represents the IPv4 address range of a user
             in the user group.

   Range-ipv6-address:  This represents the IPv6 address range of a user
             in the user group.

    +--rw user-group* [name]
    |  +--rw name                        string
    |  +--rw mac-address*                yang:mac-address
    |  +--rw (match-type)
    |     +--:(range-match-ipv4)
    |     |  +--rw range-ipv4-address
    |     |     +--rw start-ipv4-address    inet:ipv4-address-no-zone
    |     |     +--rw end-ipv4-address      inet:ipv4-address-no-zone
    |     +--:(range-match-ipv6)
    |        +--rw range-ipv6-address
    |           +--rw start-ipv6-address    inet:ipv6-address-no-zone
    |           +--rw end-ipv6-address      inet:ipv6-address-no-zone


                    Figure 9: User Group YANG Data Tree

4.2.  Device Group

   This object represents a Device-Group.  Figure 10 shows the YANG tree
   of the Device-group object.  The Device-Group object SHALL have the
   following information:

   Name:     This field identifies the name of this object.

   IPv4:     This represents the IPv4 address of a device in the device
             group.

   IPv6:     This represents the IPv6 address of a device in the device
             group.

   Range-ipv4-address:  This represents the IPv4 address range of a



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             device in the device group.

   Range-ipv6-address:  This represents the IPv6 address range of a
             device in the device group.

   Application-protocol:  This represents the application layer
             protocols of devices.  If this is not set, it cannot
             support the appropriate protocol


    +--rw device-group* [name]
    |  +--rw name                        string
    |  +--rw (match-type)
    |  |  +--:(range-match-ipv4)
    |  |  |  +--rw range-ipv4-address
    |  |  |     +--rw start-ipv4-address    inet:ipv4-address-no-zone
    |  |  |     +--rw end-ipv4-address      inet:ipv4-address-no-zone
    |  |  +--:(range-match-ipv6)
    |  |     +--rw range-ipv6-address
    |  |        +--rw start-ipv6-address    inet:ipv6-address-no-zone
    |  |        +--rw end-ipv6-address      inet:ipv6-address-no-zone
    |  +--rw application-protocol*       identityref


                   Figure 10: Device Group YANG Data Tree

4.3.  Location Group

   This object represents a location group based on either tag or other
   information.  Figure 11 shows the YANG tree of the Location-Group
   object.  The Location-Group object SHALL have the following
   information:

   Name:     This field identifies the name of this object.

   Geo-ip-ipv4:  This field represents the IPv4 Geo-ip address of a
             location [RFC8805].

   Geo-ip-ipv6:  This field represents the IPv6 Geo-ip address of a
             location [RFC8805].

   Continent:  This field represents the continent where the location
             group member is located.








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         +--rw location-group* [name]
         |  +--rw name           string
         |  +--rw geo-ip-ipv4* [ipv4-address]
         |  |  +--rw ipv4-address    inet:ipv4-address-no-zone
         |  |  +--rw ipv4-prefix?    inet:ipv4-prefix
         |  +--rw geo-ip-ipv6* [ipv6-address]
         |  |  +--rw ipv6-address    inet:ipv6-address-no-zone
         |  |  +--rw ipv6-prefix?    inet:ipv6-prefix
         |  +--rw continent?     identityref


                  Figure 11: Location Group YANG Data Tree

4.4.  URL Group

   This object represents a URL group based on a Uniform Resource
   Locator (URL) or web address.  Figure 12 shows the YANG tree of the
   URL-Group object.  The URLn-Group object SHALL have the following
   information:

   Name:     This field identifies the name of this object.

   url:      This field represents the new URL added by a user to the
             URL database.

         +--rw url-group* [name]
            +--rw name   string
            +--rw url*   string


                    Figure 12: URL Group YANG Data Tree

5.  Information Model for Threat Prevention

   The threat prevention plays an important part in the overall security
   posture by reducing the attack surfaces.  This information could come
   from various threat feeds (i.e., sources for obtaining the threat
   information).  There are multiple managed objects that constitute
   this category.  This section lists these objects and relationship
   among them.  Figure 14 shows the YANG tree of a Threat-Prevention
   object.










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                      +-------------------+
                      | Threat Prevention |
                      +---------+---------+
                                ^
                                |
                      +---------+---------+
              0..n    |         0..n      |
               +------+------+   +--------+--------+
               | Threat-feed |   | Payload-content |
               +-------------+   +-----------------+


                    Figure 13: Threat Prevention Diagram

           +--rw threat-prevention
              +--rw threat-feed-list* [name]
                 ...
              +--rw payload-content* [name]
                 ...


                Figure 14: Threat Prevention YANG Data Tree

5.1.  Threat Feed

   This object represents a threat feed which provides the signatures of
   malicious activities.  Figure 15 shows the YANG tree of a Threat-
   feed-list.  The Threat-Feed object SHALL have the following
   information:

   Name:     This field identifies the name of this object.

   Description:  This is the description of the threat feed.  The
             description should have the clear indication of the
             security attack such as attack type (e.g., APT) and file
             types used (e.g., executable malware).

   Signatures:  This field contains the threat signatures of malicious
             programs or activities provided by the threat-feed.  The
             examples of signature types are "YARA", "SURICATA", and
             "SNORT" [YARA][SURICATA][SNORT].

   It is assumed that the I2NSF User obtains the threat signatures
   (i.e., threat content patterns) from a threat-feed server (i.e., feed
   provider), which is a server providing threat signatures.  With the
   obtained threat signatures, the I2NSF User can deliver them to the
   Security Controller.  The retrieval of the threat signatures by the
   I2NSF User is out of scope in this document.



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             +--rw threat-prevention
                +--rw threat-feed-list* [name]
                   +--rw name              string
                   +--rw description?      string
                   +--rw signatures*       identityref


                   Figure 15: Threat Feed YANG Data Tree

5.2.  Payload Content

   This object represents a custom list created for the purpose of
   defining an exception to threat feeds.  Figure 16 shows the YANG tree
   of a Payload-content list.  The Payload-Content object SHALL have the
   following information:

   Name:     This field identifies the name of this object.  For
             example, the name "backdoor" indicates the payload content
             is related to a backdoor attack.

   Description:  This represents the description of how the payload
             content is related to a security attack.

   Content:  This contains the payload contents, which are involed in a
             security attack, such as strings.

             +--rw payload-content* [name]
                +--rw name         string
                +--rw description  string
                +--rw content*     binary


                Figure 16: Payload Content in YANG Data Tree

6.  Network Configuration Access Control Model (NACM) for I2NSF
    Consumer-Facing Interface

   Network Configuration Access Control Model (NACM) provides a user
   group with an access control with the following features [RFC8341]:

   *  Independent control of action, data, and notification access is
      provided.

   *  A simple and familiar set of datastore permissions is used.

   *  Support for YANG security tagging allows default security modes to
      automatically exclude sensitive data.




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   *  Separate default access modes for read, write, and execute
      permissions are provided.

   *  Access control rules are applied to configurable groups of users.

   The data model of the I2NSF Consumer-Facing Interface utilizes the
   NACM's mechanisms to manage the access control on the I2NSF Consumer-
   Facing Interface.  The NACM with the above features can be used to
   set up the access control rules of a user group in the I2NSF
   Consumer-Facing Interface.

   Figure 17 shows part of the NACM module to enable the access control
   of a user group for the I2NSF Consumer-Facing Interface.  To use the
   NACM, a user needs to configure either a NETCONF server [RFC6241] or
   a RESTCONF server [RFC8040] to enable the NACM module.  Then, the
   user can simply use an account of root or admin user for the access
   control for the module of the I2NSF Consumer-Facing Interface (i.e.,
   ietf-i2nsf-cfi-policy).  An XML example to configure the access
   control a user group for the I2NSF Consumer-Facing Interface can be
   seen in Section 9.































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   list rule {
     key "name";
     ordered-by user;
     leaf name {
       type string {
         length "1..max";
       }
       description
         "Arbitrary name assigned to the rule.";
     }

     leaf module-name {
       type union {
         type matchall-string-type;
         type string;
       }
       default "*";
       description
         "Name of the module associated with this rule."
     }

     leaf access-operations {
       type union {
         type matchall-string-type;
         type access-operations-type;
       }
       default "*";
       description
         "Access operations associated with this rule."
     }

     leaf action {
       type action-type;
       mandatory true;
       description
         "The access control action associated with the
        rule.  If a rule is determined to match a
        particular request, then this object is used
        to determine whether to permit or deny the
        request.";
     }


               Figure 17: A Part of the NACM YANG Data Model







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7.  YANG Data Model of Consumer-Facing Interface

   The main objective of this document is to provide the YANG data model
   of I2NSF Consumer-Facing Interface.  This interface can be used to
   deliver control and management messages between an I2NSF User and
   Security Controller for the I2NSF User's high-level security
   policies.

   The semantics of the data model must be aligned with the information
   model of the Consumer-Facing Interface.  The transformation of the
   information model is performed so that this YANG data model can
   facilitate the efficient delivery of the control or management
   messages.

   This data model is designed to support the I2NSF framework that can
   be extended according to the security needs.  In other words, the
   model design is independent of the content and meaning of specific
   policies as well as the implementation approach.

   With the YANG data model of I2NSF Consumer-Facing Interface, this
   document suggests use cases for security policy rules such as time-
   based firewall, VoIP/VoCN security service, and DDoS-attack
   mitigation in Section 8.

7.1.  YANG Module of Consumer-Facing Interface

   This section describes a YANG module of Consumer-Facing Interface.
   This document provides identities in the data model to be used for
   configuration of an NSF.  Each identity is used for a different type
   of configuration.  The details are explained in the description of
   each identity.  This YANG module imports from [RFC6991].  It makes
   references to [RFC0768] [RFC0792] [RFC0793] [RFC0854] [RFC0959]
   [RFC1939] [RFC2595] [RFC3022] [RFC3261] [RFC3986] [RFC4250] [RFC4340]
   [RFC4443] [RFC5321] [RFC5646] [RFC8335] [RFC8805] [RFC9051]
   [Encyclopedia-Britannica] [IANA-ICMP-Parameters]
   [IANA-ICMPv6-Parameters] [I-D.ietf-httpbis-http2bis]
   [I-D.ietf-httpbis-messaging] [I-D.ietf-httpbis-semantics]
   [I-D.ietf-i2nsf-capability-data-model]
   [I-D.ietf-i2nsf-nsf-monitoring-data-model] [I-D.ietf-tcpm-rfc793bis]
   [I-D.ietf-tsvwg-rfc4960-bis] [SNORT] [STIX] [SURICATA] [YARA].

   <CODE BEGINS> file "ietf-i2nsf-cfi-policy@2022-05-18.yang"
   module ietf-i2nsf-cfi-policy {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy";
     prefix nsfcfi;




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     import ietf-inet-types{
       prefix inet;
       reference "RFC 6991";
     }

     import ietf-yang-types{
       prefix yang;
       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>

        Editor: Jaehoon Paul Jeong
        <mailto:pauljeong@skku.edu>

        Editor: Patrick Lingga
        <mailto:patricklink@skku.edu>";

     description
       "This module is a YANG module for Consumer-Facing Interface.

        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.";

     // RFC Ed.: replace XXXX with an actual RFC number and remove
     // this note.

     revision "2022-05-18" {
       description "Initial revision.";
       reference
         "RFC XXXX: I2NSF Consumer-Facing Interface YANG Data Model";



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       // RFC Ed.: replace XXXX with an actual RFC number and remove
       // this note.
     }

     identity resolution-strategy {
       description
         "Base identity for resolution strategy";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity fmr {
       base resolution-strategy;
       description
         "Conflict resolution with First Matching Rule (FMR).";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity lmr {
       base resolution-strategy;
       description
         "Conflict resolution with Last Matching Rule (LMR)";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity pmre {
       base resolution-strategy;
       description
         "Conflict resolution with Prioritized Matching Rule with
          Errors (PMRE)";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Resolution Strategy";
     }

     identity pmrn {
       base resolution-strategy;
       description
         "Conflict resolution with Prioritized Matching Rule with
          No Errors (PMRN)";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Resolution Strategy";



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     }

     identity event {
       description
         "Base identity for policy events.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - Event";
     }

     identity system-event {
       base event;
       description
         "Base Identity for system events. System event (also called
          alert) is defined as a warning about any changes of
          configuration, any access violation, the information of
          sessions and traffic flows.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System event";
     }

     identity system-alarm {
       base event;
       description
         "Base identity for system alarms. System alarm is defined as a
          warning related to service degradation in system hardware.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm";
     }

     identity access-violation {
       base system-event;
       description
         "Access-violation system event is an event when a user tries
          to access (read, write, create, or delete) any information or
          execute commands above their privilege (i.e., not-conformant
          with the access profile).";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System event for access
          violation";
     }

     identity configuration-change {
       base system-event;
       description



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         "The configuration-change system event is an event when a user
          adds a new configuration or modify an existing configuration
          (write configuration).";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System event for
          configuration change";
     }

     identity memory-alarm {
       base system-alarm;
       description
         "Memory is the hardware to store information temporarily or for
          a short period, i.e., Random Access Memory (RAM). A
          memory-alarm is emitted when the memory usage is exceeding
          the threshold.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for
          memory";
     }

     identity cpu-alarm {
       base system-alarm;
       description
         "CPU is the Central Processing Unit that executes basic
          operations of the system. A cpu-alarm is emitted when the CPU
          usage is exceeding a threshold.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for CPU";
     }

     identity disk-alarm {
       base system-alarm;
       description
         "Disk or storage is the hardware to store information for a
          long period, i.e., Hard Disk and Solid-State Drive. A
          disk-alarm is emitted when the disk usage is exceeding a
          threshold.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for disk";
     }

     identity hardware-alarm {
       base system-alarm;
       description



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         "A hardware alarm is emitted when a hardware failure (e.g.,
          CPU, memory, disk, or interface) is detected. A hardware
          failure is a malfunction within the electronic circuits or
          electromechanical components of the hardware that makes it
          unusable.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for
          hardware";
     }

     identity interface-alarm {
       base system-alarm;
       description
         "Interface is the network interface for connecting a device
          with the network. The interface-alarm is emitted when the
          state of the interface is changed.";
       reference
         "draft-ietf-i2nsf-nsf-monitoring-data-model-18: I2NSF NSF
          Monitoring Interface YANG Data Model - System alarm for
          interface";
     }

     identity protocol {
       description
         "This identity represents the protocol types.";
     }

     identity transport-protocol {
       base protocol;
       description
         "Base identity for the Layer 4 (i.e., Transport Layer)
         Protocols";
     }

     identity tcp {
       base transport-protocol;
       description
         "Base identity for TCP condition capabilities";
       reference
         "RFC 793: Transmission Control Protocol
          draft-ietf-tcpm-rfc793bis-28: Transmission Control Protocol
          (TCP) Specification";
     }

     identity udp {
       base transport-protocol;
       description



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         "Base identity for UDP condition capabilities";
       reference
         "RFC 768: User Datagram Protocol";
     }

     identity sctp {
       base transport-protocol;
       description
         "Identity for SCTP condition capabilities";
       reference
         "draft-ietf-tsvwg-rfc4960-bis-19: Stream Control Transmission
          Protocol";
     }

     identity dccp {
       base transport-protocol;
       description
         "Identity for DCCP condition capabilities";
       reference
         "RFC 4340: Datagram Congestion Control Protocol";
     }

     identity application-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
         "draft-ietf-httpbis-semantics-19: HTTP Semantics
          draft-ietf-httpbis-messaging-19: HTTP/1.1";
     }

     identity https {
       base application-protocol;
       description
         "The identity for Hypertext Transfer Protocol version 1.1
          (HTTP/1.1) over TLS.";
       reference
         "draft-ietf-httpbis-semantics-19: HTTP Semantics
          draft-ietf-httpbis-messaging-19: HTTP/1.1";



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     }

     identity http2 {
       base application-protocol;
       description
         "The identity for Hypertext Transfer Protocol version 2
          (HTTP/2).";
       reference
         "draft-ietf-httpbis-http2bis-07: HTTP/2";
     }

     identity https2 {
       base application-protocol;
       description
         "The identity for Hypertext Transfer Protocol version 2
          (HTTP/2) over TLS.";
       reference
         "draft-ietf-httpbis-http2bis-07: HTTP/2";
     }

     identity ftp {
       base application-protocol;
       description
         "The identity for File Transfer Protocol.";
       reference
         "RFC 959: File Transfer Protocol (FTP)";
     }

     identity ssh {
       base application-protocol;
       description
         "The identity for Secure Shell (SSH) protocol.";
       reference
         "RFC 4250: The Secure Shell (SSH) Protocol";
     }

     identity telnet {
       base application-protocol;
       description
         "The identity for telnet.";
       reference
         "RFC 854: Telnet Protocol";
     }

     identity smtp {
       base application-protocol;
       description
         "The identity for Simple Mail Transfer Protocol.";



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       reference
         "RFC 5321: Simple Mail Transfer Protocol (SMTP)";
     }

     identity pop3 {
       base application-protocol;
       description
         "The identity for Post Office Protocol 3 (POP3).";
       reference
         "RFC 1939: Post Office Protocol - Version 3 (POP3)";
     }

     identity pop3s {
       base application-protocol;
       description
         "The identity for Post Office Protocol 3 (POP3) over TLS";
       reference
         "RFC 1939: Post Office Protocol - Version 3 (POP3)
          RFC 2595: Using TLS with IMAP, POP3 and ACAP";
     }

     identity imap {
       base application-protocol;
       description
         "The identity for Internet Message Access Protocol (IMAP).";
       reference
         "RFC 9051: Internet Message Access Protocol (IMAP) - Version
          4rev2";
     }

     identity imaps {
       base application-protocol;
       description
         "The identity for Internet Message Access Protocol (IMAP) over
          TLS";
       reference
         "RFC 9051: Internet Message Access Protocol (IMAP) - Version
          4rev2";
     }

     identity action {
       description
         "Base identity for action";
     }

     identity primary-action {
       base action;
       description



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         "Base identity for primary action. Primary action is an action
          that handle the forwarding of the packets or flows in an
          NSF.";
     }

     identity secondary-action {
       base action;
       description
         "Base identity for secondary action. Secondary action is an
          action in the background that does not affect the network,
          such as logging.";
     }

     identity ingress-action {
       base action;
       description
         "Base identity for ingress action. The action to handle the
          network traffic that is entering the secured network.";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Ingress Action";
     }

     identity egress-action {
       base action;
       description
         "Base identity for egress action. The action to handle the
          network traffic that is exiting the secured network.";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Egress Action";
     }

     identity pass {
       base ingress-action;
       base egress-action;
       description
         "The pass action allows traffic that matches
          the rule to proceed through the NSF to reach the
          destination.";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity drop {
       base ingress-action;



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       base egress-action;
       description
         "The drop action denies the traffic that
          matches the rule. The drop action should do a silent drop,
          which does not give any response to the source.";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity reject {
       base ingress-action;
       base egress-action;
       description
         "The reject action denies a packet to go through the NSF
          entering or exiting the internal network and sends a response
          back to the source. The response depends on the packet and
          implementation. For example, a TCP packet is rejected with
          TCP RST response or a UDP packet may be rejected with an
          ICMPv4 response message with Type 3 Code 3 or ICMPv6 response
          message Type 1 Code 4 (i.e., Destination Unreachable:
          Destination port unreachable).";
     }

     identity mirror {
       base ingress-action;
       base egress-action;
       description
         "The mirror action copies a packet and sends the packet's copy
          to the monitoring entity while still allowing the packet or
          flow to go through the NSF.";
       reference
         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity rate-limit {
       base ingress-action;
       base egress-action;
       description
         "The rate limit action limits the number of packets or flows
          that can go through the NSF by dropping packets or flows
          (randomly or systematically). The drop mechanism, e.g., silent
          drop and unreachable drop (i.e., reject), is up to the
          implementation";
       reference



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         "draft-ietf-i2nsf-capability-data-model-31:
          I2NSF Capability YANG Data Model - Actions and
          Default Action";
     }

     identity invoke-signaling {
       base egress-action;
       description
         "The invoke-signaling action is used to convey information of
          the event triggering this action to a monitoring entity.";
     }

     identity tunnel-encapsulation {
       base egress-action;
       description
         "The tunnel encapsulation action is used to encapsulate the
          packet to be tunneled across the network to enable a secure
          connection.";
     }

     identity forwarding {
       base egress-action;
       description
         "The forwarding action is used to relay the packet from one
          network segment to another node in the network.";
     }

     identity transformation {
       base egress-action;
       description
         "The transformation action is used to transform a packet by
          modifying it (e.g., HTTP-to-CoAP packet translation).
          Note that a subset of transformation (e.g., HTTP-to-CoAP) is
          handled in this YANG module, rather than all the existing
          transformations.  Specific algorithmic transformations can be
          executed by a middlebox (e.g., NSF) for a given transformation
          name.";
       reference
         "RFC 8075: Guidelines for Mapping Implementations: HTTP to the
          Constrained Application Protocol (CoAP) - Translation between
          HTTP and CoAP.";
     }

     identity log-action {
       base action;
       description
         "Base identity for log action";
     }



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     identity rule-log {
       base log-action;
       description
         "Log the policy rule that has been triggered by a packet or
          flow.";
     }

     identity session-log {
       base log-action;
       description
         "A session is a connection (i.e., traffic flow) of a data plane
          that includes source and destination information of IP
          addresses and transport port numbers with the protocol used.
          Log the session that triggered a policy rule.";
     }

     identity icmp-message {
       description
         "Base identity for ICMP Message types. Note that this YANG
          module only provide ICMP messages that is shared between
          ICMPv4 and ICMPv6 (e.g., Destination Unreachable: Port
          Unreachable which is ICMPv4 type 3 code 3 or ICMPv6 type 1
          code 4).";
       reference
         "RFC  792: Internet Control Message Protocol
          RFC 8335: PROBE: A Utility for Probing Interfaces
          IANA: Internet Control Message Protocol (ICMP)
          Parameters
          IANA: Internet Control Message Protocol version 6
          (ICMPv6) Parameters";
     }

     identity echo-reply {
       base icmp-message;
       description
         "Identity for 'Echo Reply' ICMP message type 0 in ICMPv4 or
          type 129 in ICMPv6";
     }

     identity destination-unreachable {
       base icmp-message;
       description
         "Identity for 'Destination Unreachable' ICMP message type 3 in
          ICMPv4 or type 1 in ICMPv6";
     }

     identity redirect {
       base icmp-message;



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       description
         "Identity for 'Redirect' ICMP message type 5 in ICMPv4
          or type 137 in ICMPv6";
     }

     identity echo {
       base icmp-message;
       description
         "Identity for 'Echo' ICMP message type 8 in ICMPv4 or type 128
          in ICMPv6";
     }

     identity router-advertisement {
       base icmp-message;
       description
         "Identity for 'Router Advertisement' ICMP message type 9 in
          ICMPv4 or type 134 in ICMPv6";
     }

     identity router-solicitation {
       base icmp-message;
       description
         "Identity for 'Router Solicitation' ICMP message type 10 in
          ICMPv4 or type 135 in ICMPv6";
     }

     identity time-exceeded {
       base icmp-message;
       description
         "Identity for 'Time exceeded' ICMP message type 11 in ICMPv4
          or type 3 in ICMPv6";
     }

     identity parameter-problem {
       base icmp-message;
       description
         "Identity for 'Parameter Problem' ICMP message type 12 in
          ICMPv4 or type 4 in ICMPv6";
     }

     identity experimental-mobility-protocols {
       base icmp-message;
       description
         "Identity for 'Experimental Mobility Protocols' ICMP message
          type 41 in ICMPv4 or type 150 in ICMPv6";
     }

     identity extended-echo-request {



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       base icmp-message;
       description
         "Identity for 'Extended Echo Request' ICMP message type 42
          in ICMPv4 or type 160 in ICMPv6";
     }

     identity extended-echo-reply {
       base icmp-message;
       description
         "Identity for 'Extended Echo Reply' ICMP message type 43 in
          ICMPv4 or type 161 in ICMPv6";
     }

     identity port-unreachable {
       base destination-unreachable;
       description
         "Identity for port unreachable in destination unreachable
          message (i.e., ICMPv4 type 3 code 3 or ICMPv6 type 1 code 4)";
     }

     identity request-no-error {
       base extended-echo-request;
       description
         "Identity for request with no error in extended echo request
          message (i.e., ICMPv4 type 42 code 0 or ICMPv6 type 160
          code 0)";
     }

     identity reply-no-error {
       base extended-echo-reply;
       description
         "Identity for reply with no error in extended echo reply
          message (i.e., ICMPv4 type 43 code 0 or ICMPv6 type 161
          code 0)";
     }

     identity malformed-query {
       base extended-echo-reply;
       description
         "Identity for malformed query in extended echo reply message
          (i.e., ICMPv4 type 43 code 1 or ICMPv6 type 161 code 1)";
     }

     identity no-such-interface {
       base extended-echo-reply;
       description
         "Identity for no such interface in extended echo reply message
          (i.e., ICMPv4 type 43 code 2 or ICMPv6 type 161 code 2)";



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     }

     identity no-such-table-entry {
       base extended-echo-reply;
       description
         "Identity for no such table entry in extended echo reply
          message (i.e., ICMPv4 type 43 code 3 or ICMPv6 type 161
          code 3)";
     }

     identity multiple-interfaces-satisfy-query {
       base extended-echo-reply;
       description
         "Identity for multiple interfaces satisfy query in extended
          echo reply message (i.e., ICMPv4 type 43 code 4 or ICMPv6
          type 161 code 4) ";
       reference
         "RFC  792: Internet Control Message Protocol
          RFC 8335: PROBE: A Utility for Probing Interfaces";
     }

     identity signature-type {
       description
         "This represents the base identity for signature types.";
     }

     identity signature-yara {
       base signature-type;
       description
         "This represents the YARA signatures.";
       reference
         "YARA: YARA signatures are explained.";
     }

     identity signature-snort {
       base signature-type;
       description
         "This represents the SNORT signatures.";
       reference
         "SNORT: SNORT signatures are explained.";
     }

     identity signature-suricata {
       base signature-type;
       description
         "This represents the SURICATA signatures.";
       reference
         "SURICATA: SURICATA signatures are explained.";



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     }

     identity threat-feed-type {
       description
         "This represents the base identity for threat-feed.";
     }

     identity continent {
       description
         "Base identity for continent types. The continents are based
          on Encyclopedia Britannica";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity africa {
       base continent;
       description
         "Identity for Africa.";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity asia {
       base continent;
       description
         "Identity for Asia.";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity antarctica {
       base continent;
       description
         "Identity for Antarctica.";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity europe {
       base continent;
       description
         "Identity for Europe.";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity north-america {



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       base continent;
       description
         "Identity for North America.";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity south-america {
       base continent;
       description
         "Identity for South America.";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity australia {
       base continent;
       description
         "Identity for Australia";
       reference
         "Encyclopedia Britannica: Continent";
     }

     identity device-type {
       description
         "Base identity for types of device. This identity is used for
          type of the device for the source or destination of a packet
          or traffic flow. Note that the device type of either a source
          or destination can be known with the help of DHCP
          Fingerprinting and the interaction between an NSF and a DHCP
          server.";
     }

     identity computer {
       base device-type;
       description
         "Identity for computer such as personal computer (PC)
          and server.";
     }

     identity mobile-phone {
       base device-type;
       description
         "Identity for mobile-phone such as smartphone and
          cellphone";
     }

     identity voip-vocn-phone {



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       base device-type;
       description
         "Identity for VoIP (Voice over Internet Protocol) or VoCN
          (Voice over Cellular Network, such as Voice over LTE or 5G)
          phone";
     }

     identity tablet {
       base device-type;
       description
         "Identity for tablet devices";
     }

     identity network-infrastructure-device {
       base device-type;
       description
         "Identity for network infrastructure devices
          such as switch, router, and access point";
     }

     identity iot-device {
       base device-type;
       description
         "Identity for Internet of Things (IoT) devices
          such as sensors, actuators, and low-power
          low-capacity computing devices";
     }

     identity ot {
       base device-type;
       description
         "Identity for Operational Technology (OT) devices (also
          known as industrial control systems) that interact
          with the physical environment and detect or cause direct
          change through the monitoring and control of devices,
          processes, and events such as programmable logic
          controllers (PLCs), digital oscilloscopes, building
          management systems (BMS), and fire control systems";
     }

     identity vehicle {
       base device-type;
       description
         "Identity for transportation vehicles that connect to and
          share data through the Internet over Vehicle-to-Everything
          (V2X) communications.";
     }




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    /*
     * Typedefs
     */

     typedef time {
       type string {
         pattern '(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9](\.\d+)?'
           + '(Z|[\+\-]((1[0-3]|0[0-9]):([0-5][0-9])|14:00))?';
       }
       description
         "The time type represents an instance of time of zero-duration
          in the specified timezone that recurs every day.";
     }

     typedef day {
       type enumeration {
         enum monday {
           description
             "This represents Monday.";
         }
         enum tuesday {
           description
             "This represents Tuesday.";
         }
         enum wednesday {
           description
             "This represents Wednesday";
         }
         enum thursday {
           description
             "This represents Thursday.";
         }
         enum friday {
           description
             "This represents Friday.";
         }
         enum saturday {
           description
             "This represents Saturday.";
         }
         enum sunday {
           description
             "This represents Sunday.";
         }
       }
       description
         "The type for representing the day of the week.";
     }



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    /*
     * Groupings
     */

     grouping ip-address-info {
       description
         "There are two types to configure a security policy
          for an IP address, such as IPv4 adress and IPv6 address.";
       choice match-type {
         description
           "User can choose between IPv4 and IPv6.";
         case range-match-ipv4 {
           container range-ipv4-address {
             leaf start-ipv4-address {
               type inet:ipv4-address-no-zone;
               mandatory true;
               description
                 "A start IPv4 address for a range match.";
             }
             leaf end-ipv4-address {
               type inet:ipv4-address-no-zone;
               mandatory true;
               description
                 "An end IPv4 address for a range match.";
             }
             description
               "A range match for IPv4 addresses is provided.
                Note that the start IPv4 address must be lower than
                the end IPv4 address.";
           }
         }
         case range-match-ipv6 {
           container range-ipv6-address {
             leaf start-ipv6-address {
               type inet:ipv6-address-no-zone;
               mandatory true;
               description
                 "A start IPv6 address for a range match.";
             }
             leaf end-ipv6-address {
               type inet:ipv6-address-no-zone;
               mandatory true;
               description
                 "An end IPv6 address for a range match.";
             }
             description
               "A range match for IPv6 addresses is provided.
                Note that the start IPv6 address must be lower than



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                the end IPv6 address.";
           }
         }
       }
     }

     grouping user-group {
       description
         "This group represents user group information such as name and
          ip-address.";
       leaf name {
         type string;
         description
           "This represents the name of a user-group.  A user-group name
            is used to map a user-group's name (e.g., employees) to IP
            address(es), MAC address(es).
            It is dependent on implementation.";
       }
       leaf-list mac-address {
         type yang:mac-address;
         description
           "Represent the MAC Address of a user-group. A user-group
            can have multiple MAC Addresses.";
       }
       uses ip-address-info{
         description
           "This represents the IP addresses of a user-group.";
         refine match-type{
           mandatory true;
         }
       }
     }

     grouping device-group {
       description
         "This group represents device group information such as
          ip-address protocol.";
       leaf name {
         type string;
         description
           "This represents the name of a device-group.";
       }
       uses ip-address-info{
         refine match-type{
           mandatory true;
         }
       }
       leaf-list application-protocol {



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         type identityref {
           base application-protocol;
         }
         description
           "This represents the application layer protocols of devices.
            If this is not set, it cannot support the appropriate
            protocol";
       }
     }

     grouping location-group {
       description
         "This group represents location-group information such as
          geo-ip and continent.";
       leaf name {
         type string;
         description
           "This represents the name of a location.";
       }
       list geo-ip-ipv4 {
         key "ipv4-address";
         description
           "This represents the list of IPv4 addresses based on a
            location.";
         leaf ipv4-address{
           type inet:ipv4-address-no-zone;
           description
             "This represents an IPv4 geo-ip address of a location.";
         }
         leaf ipv4-prefix{
           type inet:ipv4-prefix;
           description
             "This represents the prefix for the IPv4 addresses.";
         }
       }
       list geo-ip-ipv6 {
         key "ipv6-address";
         description
           "This represents the list of IPv6 addresses based on a
            location.";
         leaf ipv6-address{
           type inet:ipv6-address-no-zone;
           description
             "This represents an IPv6 geo-ip address of a location.";
         }
         leaf ipv6-prefix{
           type inet:ipv6-prefix;
           description



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             "This represents the prefix for the IPv6 addresses.";
         }
       }
       leaf continent {
         type identityref {
           base continent;
         }
         default asia;
         description
           "location-group has geo-ip addresses of the corresponding
            continent.";
       }
       reference
         "RFC 8805: A Format for Self-Published IP Geolocation Feeds -
          An access control for a geographical location (i.e.,
          geolocation) that has the corresponding IP prefix.";
     }

     grouping payload-string {
       description
         "The grouping for payload-string content.  It contains
          information such as name and string content.";
     }

     list i2nsf-cfi-policy {
       key "name";
       description
         "This is a security policy list.  Each policy in the list
          contains a list of security policy rules, and is a policy
          instance to have the information of where and when a policy
          needs to be applied.";
       leaf name {
         type string;
         description
           "The name which identifies the policy.";
       }
       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-WY-Za-wy-z]'
                 + '(-([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]'



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                 + '|[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 all of the 'leaf description' described in the
            'i2nsf-cfi-policy'.

            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";
       }
       leaf resolution-strategy {
         type identityref {
           base resolution-strategy;
         }
         default fmr;
         description
           "The resolution strategies that can be used to
            specify how to resolve conflicts that occur between
            actions of the same or different policy rules that
            are matched and contained in this particular NSF";

         reference
           "draft-ietf-i2nsf-capability-data-model-31:
            I2NSF Capability YANG Data Model - Resolution strategy";
       }
       list rules {
         key "name";

         description
           "There can be a single or multiple number of rules.";
         leaf name {



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           type string;
           description
             "This represents the name for a rule.";
         }

         leaf priority {
           type uint8 {
             range "1..255";
           }
           description
             "The priority keyword comes with a mandatory
              numeric value which can range from 1 through 255.
              Note that a higher number means a higher priority";
         }

         container event {
           description
             "This represents an event (i.e., a security event), for
              which a security rule is made.";
           leaf-list system-event {
             type identityref {
               base system-event;
             }
             description
               "The security policy rule according to
                system events.";
           }

           leaf-list system-alarm {
             type identityref {
               base system-alarm;
             }
             description
               "The security policy rule according to
                system alarms.";
           }
         }

         container condition {
           description
           "Conditions for general security policies.";
           container firewall {
             description
               "A general firewall condition based on the packet
                header.";
             leaf-list source {
               type union {
                 type leafref {



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                   path "/i2nsf-cfi-policy/endpoint-groups/"
                      + "user-group/name";
                 }
                 type leafref {
                   path "/i2nsf-cfi-policy/endpoint-groups/"
                      + "device-group/name";
                 }
               }
               description
               "This describes the path of the source.";
             }

             leaf-list destination {
               type union {
                 type leafref {
                   path "/i2nsf-cfi-policy/endpoint-groups/"
                      + "user-group/name";
                 }
                 type leafref {
                   path "/i2nsf-cfi-policy/endpoint-groups/"
                      + "device-group/name";
                 }
               }
               description
                 "This describes the path to the destinations.";
             }

             leaf transport-layer-protocol {
               type identityref {
                 base transport-protocol;
               }
               description
                 "The transport-layer protocol to be matched.";
             }

             container range-port-number {
               leaf start-port-number {
                 type inet:port-number;
                 description
                   "A start port number for range match.";
               }
               leaf end-port-number {
                 type inet:port-number;
                 description
                   "An end port number for range match.";
               }
               description
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                  that the start port number value must be lower than
                  the end port  number value";
             }

             container icmp {
               description
                  "Represents the ICMPv4 and ICMPv6 packet header
                   information to determine if the set of policy
                   actions in this ECA policy rule should be executed
                   or not.";
                reference
                  "RFC  792: Internet Control Message Protocol
                   RFC 8335: PROBE: A Utility for Probing Interfaces";

               leaf-list message {
                 type identityref {
                   base icmp-message;
                 }
                 description
                   "The security policy rule according to
                    ICMP message. The type is representing the
                    ICMP message corresponds to the ICMP type and
                    code.";
                 reference
                   "RFC  792: Internet Control Message Protocol
                    RFC 8335: PROBE: A Utility for Probing Interfaces
                    IANA: Internet Control Message Protocol (ICMP)
                    Parameters
                    IANA: Internet Control Message Protocol version 6
                    (ICMPv6) Parameters";
               }
             }
           }

           container ddos {
             description
               "A condition for a DDoS attack.";
             container rate-limit {
               description
                 "This describes the rate-limit.";
               leaf packet-rate-threshold {
                 type uint64;
                 description
                   "This is a trigger value for a rate limit of packet
                    rate for a DDoS-attack mitigation.";
               }
               leaf byte-rate-threshold {
                 type uint64;



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                 description
                   "This is a trigger value for a rate limit of byte
                    rate for a DDoS-attack mitigation.";
               }
               leaf flow-rate-threshold {
                 type uint64;
                 description
                   "This is a trigger value for a rate limit of flow
                    rate for a DDoS-attack mitigation.";
               }
             }
           }

           container anti-virus {
             description
              "A condition for anti-virus";

             leaf-list exception-files {
               type string;
               description
                 "The type or name of the files to be excluded by the
                  antivirus. This can be used to keep the known
                  harmless files.
                  If the value starts with a regular expression (e.g.,
                  '*.exe'), the antivirus should interpret it as a
                  file pattern/type to be excluded.
                  If the value does not start with a dot (e.g.,
                  'example.exe'), the antivirus should interpret it as
                  a file name/path to be excluded.";
             }
           }

           container payload {
             description
               "A condition based on a packet's content.";
             leaf-list content {
               type leafref {
                 path "/i2nsf-cfi-policy/threat-prevention/"
                    + "payload-content/name";
               }
               description
                 "This describes the paths to a packet content's";
             }
           }

           container url-category {
             description
               "Condition for url category";



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             leaf url-name {
               type leafref {
                 path "/i2nsf-cfi-policy/endpoint-groups/"
                    + "url-group/name";
               }
               description
                 "This is description for the condition of a URL's
                  category such as SNS sites, game sites, ecommerce
                  sites, company sites, and university sites.";
             }
           }

           container voice {
             description
               "For the VoIP/VoCN security system, a VoIP/
                VoCN security system can monitor each
                VoIP/VoCN flow and manage VoIP/VoCN
                security rules controlled by a centralized
                server for VoIP/VoCN security service
                (called VoIP IPS). The VoIP/VoCN security
                system controls each switch for the
                VoIP/VoCN call flow management by
                manipulating the rules that can be added,
                deleted, or modified dynamically.
                Note that VoIP is Voice over Internet Protocol
                and VoCN is Voice over Cellular Network such as
                Voice over LTE or 5G";
             reference
               "RFC 3261: SIP: Session Initiation Protocol";

             leaf-list source-id {
               type string;
               description
                 "The security policy rule according to
                  a source voice ID for VoIP and VoCN.";
             }

             leaf-list destination-id {
               type string;
               description
                 "The security policy rule according to
                  a destination voice ID for VoIP and VoCN.";
             }

             leaf-list user-agent {
               type string;
               description
                 "The security policy rule according to



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                  an user agent for VoIP and VoCN.";
             }
           }

           container context {
             description
               "Condition for matching the context of the packet, such
                as geographic location, time, packet direction";
             container time {
               description
                 "The time when a security policy rule should be
                  applied.";
               leaf start-date-time {
                 type yang:date-and-time;
                 description
                   "This is the start date and time for a security
                    policy rule.";
               }
               leaf end-date-time {
                 type yang:date-and-time;
                 description
                   "This is the end date and time for a security policy
                    rule.  The policy rule will stop working after the
                    specified end date and time.";
               }
               container period {
                 when
                   "../frequency!='only-once'";
                 description
                   "This represents the repetition time.  In the case
                    where the frequency is weekly, the days can be
                    set.";
                 leaf start-time {
                   type time;
                   description
                     "This is a period's start time for an event.";
                 }
                 leaf end-time {
                   type time;
                   description
                     "This is a period's end time for an event.";
                 }
                 leaf-list day {
                   when
                     "../../frequency='weekly'";
                   type day;
                   min-elements 1;
                   description



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                     "This represents the repeated day of every week
                     (e.g., Monday and Tuesday).  More than one day can
                     be specified.";
                 }
                 leaf-list date {
                   when
                     "../../frequency='monthly'";
                   type int8 {
                     range "1..31";
                   }
                   min-elements 1;
                   description
                     "This represents the repeated date of every month.
                      More than one date can be specified.";
                 }
                 leaf-list month {
                   when
                     "../../frequency='yearly'";
                   type string{
                     pattern '\d{2}-\d{2}';
                   }
                   min-elements 1;
                   description
                     "This represents the repeated date and month of
                      every year.  More than one can be specified.
                      A pattern used here is Month and Date (MM-DD).";
                 }
               }

               leaf frequency {
                 type enumeration {
                   enum only-once {
                     description
                       "This represents that the rule is immediately
                        enforced only once and not repeated. The policy
                        will continuously be active from the
                        start-date-time to the end-date-time.";
                   }
                   enum daily {
                     description
                       "This represents that the rule is enforced on a
                        daily basis. The policy will be repeated daily
                        until the end-date-time.";
                   }
                   enum weekly {
                     description
                       "This represents that the rule is enforced on a
                        weekly basis. The policy will be repeated weekly



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                        until the end-date-time. The repeated days can
                        be specified.";
                   }
                   enum monthly {
                     description
                       "This represents that the rule is enforced on a
                        monthly basis. The policy will be repeated
                        monthly until the end-date-time.";
                   }
                   enum yearly {
                     description
                       "This represents that the rule is enforced on a
                        yearly basis.  The policy will be repeated
                        yearly until the end-date-time.";
                   }
                 }
                 default only-once;
                 description
                   "This represents how frequently the rule should be
                    enforced.";
               }
             }

             container application {
               description
                 "Condition for application";
               leaf-list protocol {
                 type identityref {
                   base application-protocol;
                 }
                 description
                   "The condition based on the application layer
                    protocol";
               }
             }

             container device-type {
               description
                 "Condition for type of the destination device";
               leaf-list device {
                 type identityref {
                   base device-type;
                 }
                 description
                   "The device attribute that can identify a device,
                    including the device type (i.e., router, switch,
                    pc, ios, or android) and the device's owner as
                    well.";



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               }
             }

             container users {
               description
                 "Condition for users";
               list user {
                 key "id";
                 description
                   "The user with which the traffic flow is associated
                    can be identified by either a user ID or username.
                    The user-to-IP address mapping is assumed to be
                    provided by the unified user management system via
                    network.";
                 leaf id {
                   type uint32;
                   description
                     "The ID of the user.";
                 }
                 leaf name {
                   type string;
                   description
                     "The name of the user.";
                 }
               }
               list group {
                 key "id";
                 description
                   "The user group with which the traffic flow is
                    associated can be identified by either a group ID
                    or group name. The group-to-IP address and
                    user-to-group mappings are assumed to be provided by
                    the unified user management system via network.";
                 leaf id {
                   type uint32;
                   description
                     "The ID of the group.";
                 }
                 leaf name {
                   type string;
                   description
                     "The name of the group.";
                 }
               }
             }

             container geographic-location {
               description



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                 "A condition for a location-based connection";
               leaf-list source {
                 type leafref {
                   path "/i2nsf-cfi-policy/endpoint-groups/"
                      + "location-group/name";
                 }
                 description
                   "This describes the paths to a location's sources.";
               }
               leaf-list destination {
                 type leafref {
                   path "/i2nsf-cfi-policy/endpoint-groups/"
                      + "location-group/name";
                 }
                 description
                   "This describes the paths to a location's
                    destinations.";
               }
             }
           }

           container threat-feed {
             description
               "A condition based on the threat-feed information.";
             leaf-list name {
               type leafref {
                 path "/i2nsf-cfi-policy/threat-prevention/"
                    + "threat-feed-list/name";
               }
               description
                 "This describes the paths to a threat-feed's sources.";
             }
           }
         }

         container action {
           description
             "This is the action container.";
           container primary-action {
             description
               "This represents primary actions (e.g., ingress and
                egress actions) to be applied to a condition.
                If this is not set, it cannot support the primary
                actions.";
             leaf action {
               type identityref {
                 base primary-action;
               }



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               description
                 "Ingress actions: pass, drop, reject, rate-limit,
                  and mirror.
                  Egress actions: pass, drop, reject, rate-limit,
                  mirror, invoke-signaling, tunnel-encapsulation,
                  forwarding, and transformation..";
             }
           }
           container secondary-action {
             description
               "This represents secondary actions (e.g., log and syslog)
                to be applied if they are needed.  If this is not set,
                it cannot support the secondary actions.";
             leaf log-action {
               type identityref {
                 base secondary-action;
               }
               description
                 "Log action: rule log and session log";
             }
           }
         }
       }

       container endpoint-groups {
         description
           "A logical entity in a business environment, where a security
            policy is to be applied.";
         list user-group{
           uses user-group;
           key "name";
           description
             "This represents a user group.";
         }
         list device-group {
           key "name";
           uses device-group;
           description
             "This represents a device group.";
         }
         list location-group{
           key "name";
           uses location-group;
           description
             "This represents a location group.";
         }
         list url-group {
           key "name";



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           description
             "This describes the list of URL.";
           leaf name {
             type string;
             description
               "This is the name of URL group, e.g., SNS sites,
                gaming sites, ecommerce sites";
           }
           leaf-list url {
             type string;
             description
               "Specifies the URL to be added into the group.";
             reference
               "RFC 3986: Uniform Resource Identifier (URI): Generic
                Syntax";
           }
         }
       }

       container threat-prevention {
         description
           "The container for threat-prevention.";
         list threat-feed-list {
           key "name";
           description
             "There can be a single or multiple number of
              threat-feeds.";
           leaf name {
             type string;
             description
               "This represents the name of the threat-feed.";
           }
           leaf description {
             type string;
             description
               "This represents the descriptions of a threat-feed.  The
                description should include information, such as type,
                threat, method, and file type.  Structured Threat
                Information Expression (STIX) can be used for
                description of a threat [STIX].";
           }
           leaf-list signatures {
             type identityref {
               base signature-type;
             }
             description
               "This contains a list of signatures or hashes of the
                threats.";



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           }
         }
         list payload-content {
           key "name";
           leaf name {
             type string;
             description
               "This represents the name of a packet's payload-content.
                It should give an idea of why a specific payload content
                is marked as a threat.  For example, the name 'backdoor'
                indicates the payload content is related to a backdoor
                attack.";
           }
           leaf description {
             type string;
             description
               "This represents the description of a payload. Desecribe
                how the payload content is related to a security
                attack.";
           }
           leaf-list content {
             type binary;
             description
               "This represents the string of the payload contents.
                This content leaf-list contains the payload of a packet
                to analyze a threat. Due to the types of threats, the
                type of the content is defined as a binary to
                accommodate any kind of a payload type such as HTTP,
                HTTPS, and SIP.";
           }
           description
             "This represents a payload-string group.";
         }
       }
     }
   }
   <CODE ENDS>

               Figure 18: YANG for Consumer-Facing Interface

8.  XML Configuration Examples of High-Level Security Policy Rules

   This section shows XML configuration examples of high-level security
   policy rules that are delivered from the I2NSF User to the Security
   Controller over the Consumer-Facing Interface.  The considered use
   cases are: Database registration, time-based firewall for web
   filtering, VoIP/VoCN security service, and DDoS-attack mitigation.




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8.1.  Database Registration: Information of Positions and Devices
      (Endpoint Group)

   If new endpoints are introduced to the network, it is necessary to
   first register their data to the database.  For example, if new
   members are newly introduced in either of three different groups
   (i.e., user-group, device-group, and url-group), each of them should
   be registered with information such as ip-addresses or protocols used
   by devices.

   Figure 19 shows an example XML representation of the registered
   information for the user-group and device-group with IPv4 addresses
   [RFC5737].

   <?xml version="1.0" encoding="UTF-8" ?>
   <i2nsf-cfi-policy
    xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy">
     <name>security_policy_for_blocking_sns</name>
     <endpoint-groups>
       <user-group>
         <name>employees</name>
         <range-ipv4-address>
           <start-ipv4-address>192.0.2.11</start-ipv4-address>
           <end-ipv4-address>192.0.2.90</end-ipv4-address>
         </range-ipv4-address>
       </user-group>
       <device-group>
         <name>webservers</name>
         <range-ipv4-address>
           <start-ipv4-address>198.51.100.11</start-ipv4-address>
           <end-ipv4-address>198.51.100.20</end-ipv4-address>
         </range-ipv4-address>
         <application-protocol>http</application-protocol>
         <application-protocol>https</application-protocol>
       </device-group>
       <url-group>
         <name>sns-websites</name>
         <url>example1.com</url>
         <url>example2.com</url>
       </url-group>
     </endpoint-groups>
   </i2nsf-cfi-policy>


       Figure 19: Registering User-group and Device-group Information
                            with IPv4 Addresses





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   Also, Figure 20 shows an example XML representation of the registered
   information for the user-group and device-group with IPv6 addresses
   [RFC3849].

   <?xml version="1.0" encoding="UTF-8" ?>
   <i2nsf-cfi-policy
    xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy">
     <name>security_policy_for_blocking_sns</name>
     <endpoint-groups>
       <user-group>
         <name>employees</name>
         <range-ipv6-address>
           <start-ipv6-address>2001:db8:0:1::11</start-ipv6-address>
           <end-ipv6-address>2001:db8:0:1::90</end-ipv6-address>
         </range-ipv6-address>
       </user-group>
       <device-group>
         <name>webservers</name>
         <range-ipv6-address>
           <start-ipv6-address>2001:db8:0:2::11</start-ipv6-address>
           <end-ipv6-address>2001:db8:0:2::20</end-ipv6-address>
         </range-ipv6-address>
         <application-protocol>http</application-protocol>
         <application-protocol>https</application-protocol>
       </device-group>
       <url-group>
         <name>sns-websites</name>
         <url>SNS_1</url>
         <url>SNS_2</url>
       </url-group>
     </endpoint-groups>
   </i2nsf-cfi-policy>


       Figure 20: Registering User-group and Device-group Information
                            with IPv6 Addresses

8.2.  Scenario 1: Block SNS Access during Business Hours

   The first example scenario is to "block SNS access during office
   hours" using a time-based firewall policy.  In this scenario, all
   users registered as "employees" in the user-group list are unable to
   access Social Networking Services (SNS) during the office hours
   (weekdays).  The XML instance is described below:







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   <?xml version="1.0" encoding="UTF-8" ?>
   <i2nsf-cfi-policy
    xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy">
     <name>security_policy_for_blocking_sns</name>
     <rules>
       <name>block_access_to_sns_during_office_hours</name>
       <condition>
         <firewall>
           <source>employees</source>
         </firewall>
         <url-category>
           <url-name>sns-websites</url-name>
         </url-category>
         <context>
           <time>
             <start-date-time>2021-03-11T09:00:00.00Z</start-date-time>
             <end-date-time>2021-12-31T18:00:00.00Z</end-date-time>
             <period>
               <start-time>09:00:00Z</start-time>
               <end-time>18:00:00Z</end-time>
               <day>monday</day>
               <day>tuesday</day>
               <day>wednesday</day>
               <day>thursday</day>
               <day>friday</day>
             </period>
             <frequency>weekly</frequency>
           </time>
         </context>
       </condition>
       <actions>
         <primary-action>
           <action>drop</action>
         </primary-action>
       </actions>
     </rules>
   </i2nsf-cfi-policy>


             Figure 21: An XML Example for Time-based Firewall

   Time-based-condition Firewall

   1.  The policy name is "security_policy_for_blocking_sns".

   2.  The rule name is "block_access_to_sns_during_office_hours".

   3.  The Source is "employees".



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   4.  The destination target is "sns-websites". "sns-websites" is the
       key which represents the list containing the information, such as
       URL, about sns-websites.

   5.  The action required is to "drop" any attempt to connect to
       websites related to Social networking.

8.3.  Scenario 2: Block Malicious VoIP/VoCN Packets Coming to a Company

   The second example scenario is to "block malicious VoIP/VoCN packets
   coming to a company" using a VoIP policy.  In this scenario, the
   calls comming from from VOIP and/or VoCN sources with VoCN IDs that
   are classified as malicious are dropped.  The IP addresses of the
   employees and malicious VOIP IDs should be blocked are stored in the
   database or datastore of the enterprise.  Here and the rest of the
   cases assume that the security administrators or someone responsible
   for the existing and newly generated policies, are not aware of which
   and/or how many NSFs are needed to meet the security requirements.
   Figure 22 represents the XML document generated from YANG discussed
   in previous sections.  Once a high-level seucurity policy is created
   by a security admin, it is delivered by the Consumer-Facing
   Interface, through RESTCONF server, to the security controller.  The
   XML instance is described below:

   <?xml version="1.0" encoding="UTF-8" ?>
   <i2nsf-cfi-policy
    xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy">
     <name>
       security_policy_for_blocking_malicious_voip_packets
     </name>
     <rules>
       <name>Block_malicious_voip_and_vocn_packets</name>
       <condition>
         <voice>
           <source-id>malicious-id</source-id>
         </voice>
         <firewall>
           <destination>employees</destination>
         </firewall>
       </condition>
       <actions>
         <primary-action>
           <action>drop</action>
         </primary-action>
       </actions>
     </rules>
   </i2nsf-cfi-policy>




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            Figure 22: An XML Example for VoIP Security Service

   Custom-condition Firewall

   1.  The policy name is
       "security_policy_for_blocking_malicious_voip_packets".

   2.  The rule name is "Block_malicious_voip_and_vocn_packets".

   3.  The Source is "malicious-id".  This can be a single ID or a list
       of IDs, depending on how the ID are stored in the database.  The
       "malicious-id" is the key so that the security admin can read
       every stored malicious VOIP IDs that are named as "malicious-id".

   4.  The destination target is "employees". "employees" is the key
       which represents the list containing information about employees,
       such as IP addresses.

   5.  The action required is "drop" when any incoming packets are from
       "malicious-id".

8.4.  Scenario 3: Mitigate Flood Attacks on a Company Web Server

   The third example scenario is to "Mitigate flood attacks on a company
   web server" using a DDoS-attack mitigation policy.  Here, the time
   information is not set because the service provided by the network
   should be maintained at all times.  If the packets sent by any
   sources are more than the set threshold, then the admin can set the
   percentage of the packets to be dropped to safely maintain the
   service.  In this scenario, the source is set as "any" to block any
   sources which send abnormal amount of packets.  The destination is
   set as "web_server01".  Once the rule is set and delivered and
   enforced to the nsfs by the securiy controller, the NSFs will monitor
   the incoming packet amounts and the destination to act according to
   the rule set.  The XML instance is described below:
















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   <?xml version="1.0" encoding="UTF-8" ?>
   <i2nsf-cfi-policy
     xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy">
     <name>security_policy_for_ddos_attacks</name>
     <rules>
       <name>1000_packets_per_second</name>
       <condition>
         <ddos>
           <rate-limit>
             <packet-rate-threshold>1000</packet-rate-threshold>
           </rate-limit>
         </ddos>
       </condition>
       <actions>
         <primary-action>
           <action>drop</action>
         </primary-action>
       </actions>
     </rules>
   </i2nsf-cfi-policy>


            Figure 23: An XML Example for DDoS-attack Mitigation

   DDoS-condition Firewall

   1.  The policy name is "security_policy_for_ddos_attacks".

   2.  The rule name is "1000_packets_per_second".

   3.  The rate limit exists to limit the incoming amount of packets per
       second.  In this case the rate limit is "1000" packets per
       second.  This amount depends on the packet receiving capacity of
       the server devices.

   4.  The Source is all sources which send abnormal amount of packets.

   5.  The action required is to "drop" packet reception is more than
       1000 packets per second.












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9.  XML Configuration Example of a User Group's Access Control for I2NSF
    Consumer-Facing Interface

   This is an example for creating privileges for a group of users
   (i.e., a user group) to access and use the I2NSF Consumer-Facing
   Interface to create security policies via the interface.  For the
   access control of the Consumer-Facing Interface, the NACM module can
   be used.  Figure 24 shows an XML example the access control of a user
   group (named Example-Group) for I2NSF Consumer-Facing Interface A
   group called Example-Group can be created and configured with NACM
   for the Consumer-Facing Interface.  For Example-Group, a rule list
   can created with the name of Example-Group-Rules.  Example-Group-
   Rules has two rules of Example-Group-Rule1 and Example-Group-Rule2 as
   follows.  For Example-Group-Rule1, the privilege of "Read" is allowed
   to Example-Group for the Consumer-Facing Interface.  On the other
   hand, for Example-Group-Rule2, the privileges of "Create", "Update",
   and "Delete" are denied against Example-Group for the Consumer-Facing
   Interface.

   <?xml version="1.0" encoding="UTF-8" ?>
   <nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
     <enable-nacm>true</enable-nacm>
     <groups>
       <group>
         <name>Example-Group</name>
         <user-name>Alice</user-name>
         <user-name>Bob</user-name>
         <user-name>Eve</user-name>
       </group>
     </groups>
     <rule-list>
       <name>Example-Group-Rules</name>
       <group>Example-Group</group>
       <rule>
         <name>Example-Group-Rule1</name>
         <access-operations>read</access-operations>
         <module-name>ietf-i2nsf-cfi-policy</module-name>
         <action>permit</action>
       </rule>
       <rule>
         <name>Example-Group-Rule2</name>
         <access-operations>create update delete</access-operations>
         <module-name>ietf-i2nsf-cfi-policy</module-name>
         <action>deny</action>
       </rule>
     </rule-list>
   </nacm>




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       Figure 24: An XML Example of a User Group's Access Control for
                      I2NSF Consumer- Facing Interface

   The access control for the I2NSF Consumer-Facing Interface is as
   follows.

   1.  The NACM is enabled.

   2.  As a group name, Example-Group is specified.

   3.  As members of the group, Alice, Bob, and Eve are specified.

   4.  As a rule list name, Example-Group-Rules is specified for
       managing privileges of Example-Group's members.

   5.  As the first rule name, Example-Group-Rule1 is specified.  This
       rule is used to give read privilege to Example-Group's members
       for the module of the I2NSF Consumer-Facing Interface.

   6.  As the second rule name, Example-Group-Rule2 is specified.  This
       rule is used to deny create, update, and delete privileges
       against Example-Group's members for the module of the I2NSF
       Consumer-Facing Interface.

10.  IANA Considerations

   This document requests IANA to register the following URI in the
   "IETF XML Registry" [RFC3688]:

   URI: urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.


   This document requests IANA to register the following YANG module in
   the "YANG Module Names" registry [RFC7950][RFC8525]:

   name: ietf-i2nsf-cfi-policy
   namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-cfi-policy
   prefix: nsfcfi
   reference: RFC XXXX

   // RFC Ed.: replace XXXX with an actual RFC number and remove
   // this note.







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11.  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 Network Configuration Access Control Model (NACM) [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 contents.  Thus, NACM SHOULD be used
   to restrict the NSF registration from unauthorized users.

   There are a number of data nodes defined in this YANG module that are
   writable, creatable, and deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations to these data nodes
   could have a negative effect on network and security operations.
   These data nodes are collected into a single list node with the
   following sensitivity/vulnerability:

   *  list i2nsf-cfi-policy: Writing to almost any element of this YANG
      module would directly impact on the configuration of NSFs, e.g.,
      completely turning off security monitoring and mitigation
      capabilities; altering the scope of this monitoring and
      mitigation; creating an overwhelming logging volume to overwhelm
      downstream analytics or storage capacity; creating logging
      patterns which are confusing; or rendering useless trained
      statistics or artificial intelligence models.

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

   *  list i2nsf-cfi-policy: The leak of this node to an attacker could
      reveal the specific configuration of security controls to an
      attacker.  An attacker can craft an attack path that avoids
      observation or mitigations; one may reveal topology information to
      inform additional targets or enable lateral movement; one enables
      the construction of an attack path that avoids observation or
      mitigations; one provides an indication that the operator has
      discovered the attack.  This node also holds a list of endpoint
      data that is considered private to the users.




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12.  References

12.1.  Normative References

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              DOI 10.17487/RFC0768, August 1980,
              <https://www.rfc-editor.org/info/rfc768>.

   [RFC0792]  Postel, J., "Internet Control Message Protocol", STD 5,
              RFC 792, DOI 10.17487/RFC0792, September 1981,
              <https://www.rfc-editor.org/info/rfc792>.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, DOI 10.17487/RFC0793, September 1981,
              <https://www.rfc-editor.org/info/rfc793>.

   [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>.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <https://www.rfc-editor.org/info/rfc3261>.

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





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   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC4250]  Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Protocol Assigned Numbers", RFC 4250,
              DOI 10.17487/RFC4250, January 2006,
              <https://www.rfc-editor.org/info/rfc4250>.

   [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>.

   [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>.

   [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>.

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






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   [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>.

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

   [RFC8335]  Bonica, R., Thomas, R., Linkova, J., Lenart, C., and M.
              Boucadair, "PROBE: A Utility for Probing Interfaces",
              RFC 8335, DOI 10.17487/RFC8335, February 2018,
              <https://www.rfc-editor.org/info/rfc8335>.

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

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

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

   [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
              Documents Containing YANG Data Models", BCP 216, RFC 8407,
              DOI 10.17487/RFC8407, October 2018,
              <https://www.rfc-editor.org/info/rfc8407>.

   [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>.

   [RFC8525]  Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
              and R. Wilton, "YANG Library", RFC 8525,
              DOI 10.17487/RFC8525, March 2019,
              <https://www.rfc-editor.org/info/rfc8525>.






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   [RFC8805]  Kline, E., Duleba, K., Szamonek, Z., Moser, S., and W.
              Kumari, "A Format for Self-Published IP Geolocation
              Feeds", RFC 8805, DOI 10.17487/RFC8805, August 2020,
              <https://www.rfc-editor.org/info/rfc8805>.

   [RFC9051]  Melnikov, A., Ed. and B. Leiba, Ed., "Internet Message
              Access Protocol (IMAP) - Version 4rev2", RFC 9051,
              DOI 10.17487/RFC9051, August 2021,
              <https://www.rfc-editor.org/info/rfc9051>.

   [I-D.ietf-httpbis-http2bis]
              Thomson, M. and C. Benfield, "HTTP/2", Work in Progress,
              Internet-Draft, draft-ietf-httpbis-http2bis-07, 24 January
              2022, <https://www.ietf.org/archive/id/draft-ietf-httpbis-
              http2bis-07.txt>.

   [I-D.ietf-httpbis-messaging]
              Fielding, R. T., Nottingham, M., and J. Reschke,
              "HTTP/1.1", Work in Progress, Internet-Draft, draft-ietf-
              httpbis-messaging-19, 12 September 2021,
              <https://www.ietf.org/archive/id/draft-ietf-httpbis-
              messaging-19.txt>.

   [I-D.ietf-httpbis-semantics]
              Fielding, R. T., Nottingham, M., and J. Reschke, "HTTP
              Semantics", Work in Progress, Internet-Draft, draft-ietf-
              httpbis-semantics-19, 12 September 2021,
              <https://www.ietf.org/archive/id/draft-ietf-httpbis-
              semantics-19.txt>.

   [I-D.ietf-i2nsf-capability-data-model]
              Hares, S., Jeong, J. (., Kim, J. (., Moskowitz, R., and Q.
              Lin, "I2NSF Capability YANG Data Model", Work in Progress,
              Internet-Draft, draft-ietf-i2nsf-capability-data-model-30,
              13 April 2022, <https://www.ietf.org/archive/id/draft-
              ietf-i2nsf-capability-data-model-30.txt>.

   [I-D.ietf-i2nsf-nsf-monitoring-data-model]
              Jeong, J. (., Lingga, P., Hares, S., Xia, L. (., and H.
              Birkholz, "I2NSF NSF Monitoring Interface YANG Data
              Model", Work in Progress, Internet-Draft, draft-ietf-
              i2nsf-nsf-monitoring-data-model-18, 19 April 2022,
              <https://www.ietf.org/archive/id/draft-ietf-i2nsf-nsf-
              monitoring-data-model-18.txt>.

   [I-D.ietf-tcpm-rfc793bis]
              Eddy, W. M., "Transmission Control Protocol (TCP)
              Specification", Work in Progress, Internet-Draft, draft-



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              ietf-tcpm-rfc793bis-28, 7 March 2022,
              <https://www.ietf.org/archive/id/draft-ietf-tcpm-
              rfc793bis-28.txt>.

   [I-D.ietf-tsvwg-rfc4960-bis]
              Stewart, R. R., Tüxen, M., and K. E. E. Nielsen, "Stream
              Control Transmission Protocol", Work in Progress,
              Internet-Draft, draft-ietf-tsvwg-rfc4960-bis-19, 5
              February 2022, <https://www.ietf.org/archive/id/draft-
              ietf-tsvwg-rfc4960-bis-19.txt>.

12.2.  Informative References

   [RFC3022]  Srisuresh, P. and K. Egevang, "Traditional IP Network
              Address Translator (Traditional NAT)", RFC 3022,
              DOI 10.17487/RFC3022, January 2001,
              <https://www.rfc-editor.org/info/rfc3022>.

   [RFC3444]  Pras, A. and J. Schoenwaelder, "On the Difference between
              Information Models and Data Models", RFC 3444,
              DOI 10.17487/RFC3444, January 2003,
              <https://www.rfc-editor.org/info/rfc3444>.

   [RFC3849]  Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
              Reserved for Documentation", RFC 3849,
              DOI 10.17487/RFC3849, July 2004,
              <https://www.rfc-editor.org/info/rfc3849>.

   [RFC5737]  Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks
              Reserved for Documentation", RFC 5737,
              DOI 10.17487/RFC5737, January 2010,
              <https://www.rfc-editor.org/info/rfc5737>.

   [RFC9000]  Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", RFC 9000,
              DOI 10.17487/RFC9000, May 2021,
              <https://www.rfc-editor.org/info/rfc9000>.

   [IANA-ICMP-Parameters]
              Internet Assigned Numbers Authority (IANA), "Assigned
              Internet Protocol Numbers", February 2021,
              <https://www.iana.org/assignments/protocol-numbers/
              protocol-numbers.xhtml>.








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   [IANA-ICMPv6-Parameters]
              Internet Assigned Numbers Authority (IANA), "Internet
              Control Message Procotol version 6 (ICMPv6) Parameters",
              February 2021, <https://www.iana.org/assignments/icmpv6-
              parameters/icmpv6-parameters.xhtml>.

   [Encyclopedia-Britannica]
              Britannica, "Continent", September 2020,
              <https://www.britannica.com/science/continent>.

   [YARA]     Alvarez, V., Bengen, H., Metz, J., Buehlmann, S., and W.
              Shields, "YARA", YARA
              Documents https://yara.readthedocs.io/en/v3.5.0/, August
              2020.

   [SURICATA] Julien, V. and ., "SURICATA", SURICATA Documents
              https://suricata-ids.org/docs/, August 2020.

   [SNORT]    Roesch, M., Green, C., and B. Caswell, "SNORT", SNORT
              Documents https://www.snort.org/#documents, August 2020.

   [STIX]     Jordan, B., Piazza, R., and T. Darley, "Structured Threat
              Information Expression (STIX)", STIX Version 2.1:
              Committee Specification 01 https://docs.oasis-
              open.org/cti/stix/v2.1/stix-v2.1.pdf, March 2020.

Appendix A.  Acknowledgments

   This document is a product by the I2NSF Working Group (WG) including
   WG Chairs (i.e., Linda Dunbar and Yoav Nir) and Diego Lopez.  This
   document took advantage of the review and comments from the following
   people: Roman Danyliw, Mahdi F.  Dachmehchi, Daeyoung Hyun, Jan
   Lindblad (YANG doctor), and Tom Petch.  The authors sincerely
   appreciate their sincere efforts and kind help.

   This work was supported by Institute of Information & Communications
   Technology Planning & Evaluation (IITP) grant funded by the Korea
   MSIT (Ministry of Science and ICT) (R-20160222-002755, Cloud based
   Security Intelligence Technology Development for the Customized
   Security Service Provisioning).  This work was supported in part by
   the IITP (2020-0-00395, Standard Development of Blockchain based
   Network Management Automation Technology).

Appendix B.  Contributors

   The following are co-authors of this document:





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   Patrick Lingga - Department of Electrical and Computer Engineering,
   Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon, Gyeonggi-do
   16419, Republic of Korea, EMail: patricklink@skku.edu

   Jinyong Tim Kim - Department of Electronic, Electrical and Computer
   Engineering, Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon,
   Gyeonggi-do 16419, Republic of Korea, EMail: timkim@skku.edu

   Hyoungshick Kim - Department of Computer Science and Engineering,
   Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon, Gyeonggi-do
   16419, Republic of Korea, EMail: hyoung@skku.edu

   Eunsoo Kim - Department of Electronic, Electrical and Computer
   Engineering, Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon,
   Gyeonggi-do 16419, Republic of Korea, EMail: eskim86@skku.edu

   Seungjin Lee - Department of Electronic, Electrical and Computer
   Engineering, Sungkyunkwan University, 2066 Seo-ro Jangan-gu, Suwon,
   Gyeonggi-do 16419, Republic of Korea, EMail: jine33@skku.edu

   Anil Lohiya - Juniper Networks, 1133 Innovation Way, Sunnyvale, CA
   94089, US, EMail: alohiya@juniper.net

   Dave Qi - Bloomberg, 731 Lexington Avenue, New York, NY 10022, US,
   EMail: DQI@bloomberg.net

   Nabil Bitar - Nokia, 755 Ravendale Drive, Mountain View, CA 94043,
   US, EMail: nabil.bitar@nokia.com

   Senad Palislamovic - Nokia, 755 Ravendale Drive, Mountain View, CA
   94043, US, EMail: senad.palislamovic@nokia.com

   Liang Xia - Huawei, 101 Software Avenue, Nanjing, Jiangsu 210012,
   China, EMail: Frank.Xialiang@huawei.com

Appendix C.  Changes from draft-ietf-i2nsf-consumer-facing-interface-
             dm-18

   The following changes are made from draft-ietf-i2nsf-consumer-facing-
   interface-dm-18:

   *  The Abstract is augmented to clarify the role of the Information
      Model of the Consumer-Facing Interface.

   *  This version has been updated to synchronize its contents with the
      contents in other I2NSF YANG data model documents.





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Authors' Addresses

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


   Chaehong Chung
   Department of Electronic, Electrical and Computer Engineering
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon
   Gyeonggi-Do
   16419
   Republic of Korea
   Phone: +82 31 299 4957
   Email: darkhong@skku.edu


   Tae-Jin Ahn
   Korea Telecom
   70 Yuseong-Ro, Yuseong-Gu
   Daejeon
   305-811
   Republic of Korea
   Phone: +82 42 870 8409
   Email: taejin.ahn@kt.com


   Rakesh Kumar
   Juniper Networks
   1133 Innovation Way
   Sunnyvale, CA 94089
   United States of America
   Email: rkkumar@juniper.net








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   Susan Hares
   Huawei
   7453 Hickory Hill
   Saline, MI 48176
   United States of America
   Phone: +1-734-604-0332
   Email: shares@ndzh.com












































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