I2NSF Registration Interface YANG Data Model for NSF Capability Registration

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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

A number of Network Security Functions (NSF) may exist in the Interface to Network Security Functions (I2NSF) framework [RFC8329]. Since each of these NSFs likely has different security capabilities from each other, it is important to register the security capabilities of the NSFs to the Security Controller (i.e., Network Management Operator System). In addition, it is required to search NSFs of some required security capabilities on demand. As an example, if additional security capabilities are required to serve some security service request(s) from an I2NSF User, the security controller SHOULD be able to request the DMS for NSFs that have the required security capabilities.¶

As the main focus of the YANG module defined in [I-D.ietf-i2nsf-capability-data-model] is to define the security capabilities of an NSF, it lacks in some information (e.g., network access information to an NSF) needed by the Security Controller. This information can be provided by the DMS as it is the vendor system that provides and deploys the NSFs. Hence, this document provides extended information for the I2NSF Registration Interface.¶

This document describes an information model (see Section 4) and an augmented YANG [RFC7950] data model from I2NSF Capability YANG data model [I-D.ietf-i2nsf-capability-data-model] (see Section 5) for the I2NSF Registration Interface [RFC8329] between the Security Controller and the developer's management system (DMS) to support NSF capability registration and query via the registration interface. It also describes the operations which SHOULD be performed by the Security Controller and the DMS via the Registration Interface using the defined model. Note that in either NETCONF [RFC6241] or RESTCONF [RFC8040] parlance through the I2NSF Registration Interface, the Security Controller is the server, and the DMS is the client because the Security Controller and DMS run the server and client for either NETCONF or RESTCONF, respectively.¶

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 following terms defined in [RFC3444], [RFC8329] and [I-D.ietf-i2nsf-capability-data-model].¶

• Network Security Function (NSF): A function that is responsible for a specific treatment of received packets. A Network Security Function can act at various layers of a protocol stack (e.g., at the network layer or other OSI layers). Sample Network Security Service Functions are as follows: Firewall, Intrusion Prevention/Detection System (IPS/IDS), Deep Packet Inspection (DPI), Application Visibility and Control (AVC), network virus and malware scanning, sandbox, Data Loss Prevention (DLP), Distributed Denial of Service (DDoS) mitigation and TLS proxy.¶
• Data Model: Data Models define managed objects at a lower level of abstraction, which include implementation- and protocol-specific details, e.g., rules that explain how to map managed objects onto lower-level protocol constructs [RFC3444].¶
• Information Model: Information Models are primarily useful for designers to describe the managed environment, for operators to understand the modeled objects, and for implementers as a guide to the functionality that must be described and coded in the Data Models [RFC3444].¶
• YANG: 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. Objectives

• Registering NSFs with the I2NSF framework: Developer's Management System (DMS) in I2NSF framework is typically run by an NSF vendor, and uses Registration Interface to provide NSFs information (i.e., capability, specification, and access information) developed by the NSF vendor to Security Controller. Since there may be multiple vendors that provide NSFs for a target network, the I2NSF Registration Interface can be used as a standard interface for the DMSs to provide NSFs capability information to the Security Controller. For the registered NSFs, Security Controller maintains a catalog of the capabilities of those NSFs to select appropriate NSFs for the requested security services.¶
• Updating the capabilities of registered NSFs: After an NSF is registered with Security Controller, some modifications on the capability of the NSF MAY be required later. In this case, DMS uses Registration Interface to deliver the update of the capability of the NSF to the Security Controller, and this update MUST be reflected on the catalog of NSFs existing in the Security Controller. That is, whenever there are updates on the NSFs, the DMS sends the updated, whole NSF capability information to the Security Controller. The Security Controller updates its catalog of NSFs with the updated NSF capability information.¶
• Asking DMS about some required capabilities: In cases that some security capabilities are required to serve the security service request from an I2NSF User, the Security Controller searches through the registered NSFs to find ones that can provide the required capabilities. But Security Controller might fail to find any NSFs having the required capabilities among the registered NSFs. In this case, Security Controller needs to request DMS for additional NSF(s) information that can provide the required security capabilities via Registration Interface.¶

4. Information Model

The I2NSF registration interface is used by Security Controller and Developer's Management System (DMS) in I2NSF framework. Figure 1 shows the information model of the I2NSF registration interface, which consists of two submodels: NSF capability registration and NSF capability query. Each submodel is used for the operations listed above. The remainder of this section will provide in-depth explanation of each submodel.¶

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |      I2NSF Registration Interface Information Model       |
  |                                                           |
  |         +-+-+-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+-+-+          |
  |         | NSF Capability  |  | NSF Capability  |          |
  |         | Registration    |  | Query           |          |
  |         +-+-+-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+-+-+          |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       +-+-+-+-+-+-+-+-+-+
                       | NSF Capability  |
                       | Registration    |
                       +-+-+-+-+^+-+-+-+-+
                                |
          +---------------------+--------------------+
          |                     |                    |
          |                     |                    |
    +-+-+-+-+-+-+       +-+-+-+-+-+-+-+-+      +-+-+-+-+-+-+-+
    |   NSF     |       | NSF Capability|      | NSF Access  |
    |   Name    |       | Information   |      | Information |
    +-+-+-+-+-+-+       +-+-+-+-+-+-+-+-+      +-+-+-+-+-+-+-+

                          +-+-+-+-+-+-+-+-+-+
                          | NSF Capability  |
                          |   Information   |
                          +-+-+-+-^-+-+-+-+-+
                                  |
                                  |
           +----------------------+----------------------+
           |                                             |
           |                                             |
   +-+-+-+-+-+-+-+-+                             +-+-+-+-+-+-+-+-+
   |     I2NSF     |                             |      NSF      |
   | Capabilities  |                             | Specification |
   +-+-+-+-+-+-+-+-+                             +-+-+-+-+-+-+-+-+
           |
    +------+-------------+----------------+----------------+-------+
    |                    |                |                |       |
+-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+ |
| Directional |  |    Event    |  |  Condition  |  |    Action   | |
| Capabilities|  | Capabilities|  | Capabilities|  | Capabilities| |
+-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+ |
                                                                   |
                 +--------------------+--------------------+-------+
                 |                    |
           +-+-+-+-+-+-+-+      +-+-+-+-+-+-+-+
           | Resolution  |      |   Default   |
           | Strategy    |      |   Action    |
           | Capabilities|      | Capabilities|
           +-+-+-+-+-+-+-+      +-+-+-+-+-+-+-+

                      +-----------------+
                      |       NSF       |
                      |  Specification  |
                      +--------^--------+
                               |
         +-------------+-------+-----+--------------+
         |             |             |              |
         |             |             |              |
      +--+--+     +----+---+     +---+--+     +-----+-----+
      | CPU |     | Memory |     | Disk |     | Bandwidth |
      +-----+     +--------+     +------+     +-----------+

5. Data Model

  NSF Capability Registration
  augment /i2nsfcap:nsf:
    +--rw nsf-specification
    |  +--rw cpu
    |  |  +--rw model?         string
    |  |  +--rw clock-speed?   uint16
    |  |  +--rw cores?         uint8
    |  |  +--rw threads?       uint16
    |  +--rw memory
    |  |  +--rw capacity?   uint32
    |  |  +--rw speed?      uint32
    |  +--rw disk
    |  |  +--rw capacity?   uint32
    |  +--rw bandwidth
    |     +--rw outbound?   uint64
    |     +--rw inbound?    uint64
    +--rw nsf-access-info
       +--rw ip?                    union
       +--rw port?                  inet:port-number
       +--rw management-protocol?   enumeration
       +--rw name?                  string
       +--rw password?              ianach:crypt-hash

  I2NSF Capability Query
  rpcs:
    +---x nsf-capability-query
       +---w input
       |  +---w query-nsf-capability
       |     +---w directional-capabilities*           identityref
       |     +---w event-capabilities
       |     |  +---w system-event-capability*   identityref
       |     |  +---w system-alarm-capability*   identityref
       |     +---w condition-capabilities
       |     |  +---w generic-nsf-capabilities
       |     |  |  +---w ethernet-capability*   identityref
       |     |  |  +---w ipv4-capability*       identityref
       |     |  |  +---w ipv6-capability*       identityref
       |     |  |  +---w icmpv4-capability*     identityref
       |     |  |  +---w icmpv6-capability*     identityref
       |     |  |  +---w tcp-capability*        identityref
       |     |  |  +---w udp-capability*        identityref
       |     |  |  +---w sctp-capability*       identityref
       |     |  |  +---w dccp-capability*       identityref
       |     |  +---w advanced-nsf-capabilities
       |     |  |  +---w anti-ddos-capability*             identityref
       |     |  |  +---w ips-capability*                   identityref
       |     |  |  +---w anti-virus-capability*            identityref
       |     |  |  +---w url-filtering-capability*         identityref
       |     |  |  +---w voip-vocn-filtering-capability*   identityref
       |     |  +---w context-capabilities
       |     |     +---w time-capabilities*                 identityref
       |     |     +---w application-filter-capabilities*   identityref
       |     |     +---w device-type-capabilities*          identityref
       |     |     +---w user-condition-capabilities*       identityref
       |     |     +---w geographic-capabilities*           identityref
       |     +---w action-capabilities
       |     |  +---w ingress-action-capability*   identityref
       |     |  +---w egress-action-capability*    identityref
       |     |  +---w log-action-capability*       identityref
       |     +---w resolution-strategy-capabilities*   identityref
       |     +---w default-action-capabilities*        identityref
       +--ro output
          +--ro nsf-access-info
             +--ro nsf-name?              string
             +--ro ip?                    union
             +--ro port?                  inet:port-number
             +--ro management-protocol?   enumeration
             +--ro name?                  string
             +--ro password?              ianach:crypt-hash

<CODE BEGINS> file "ietf-i2nsf-registration-interface@2022-11-08.yang"

module ietf-i2nsf-registration-interface {
  yang-version 1.1;

  namespace
    "urn:ietf:params:xml:ns:yang:ietf-i2nsf-registration-interface";

  prefix
    i2nsfri;

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

  import ietf-inet-types {
    prefix inet;
    reference "RFC 6991";
  }
  import iana-crypt-hash {
    prefix ianach;
    reference "RFC 7317";
  }
  import ietf-i2nsf-capability {
    prefix i2nsfcap;
  // RFC Ed.: replace YYYY with actual RFC number of
  // draft-ietf-i2nsf-capability-data-model and remove this note.
    reference "RFC YYYY: I2NSF Capability YANG Data Model";
  }

  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: Sangwon Hyun
     <mailto:shyun@mju.ac.kr>

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

  description
    "This module defines a YANG data model for I2NSF
     Registration Interface.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
     'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
     'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this
     document are to be interpreted as described in BCP 14
     (RFC 2119) (RFC 8174) when, and only when, they appear
     in all capitals, as shown here.

     Copyright (c) 2022 IETF Trust and the persons
     identified as authors of the code. All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Revised BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX; see
     the RFC itself for full legal notices.";

  revision "2022-11-08" {
    description "Initial revision";
    reference
      "RFC XXXX: I2NSF Registration Interface YANG Data Model";
    // RFC Ed.: replace XXXX with actual RFC number and remove
    // this note
  }

  grouping nsf-specification {
    description
      "Description of the specification of an NSF";

    container cpu {
      description
        "The Central Processing Unit (CPU) specification of the NSF";

      leaf model {
        type string;
        description
          "The model name of the CPU used in the NSF.";
      }
      leaf clock-speed {
        type uint16;
        units "MHz";
        description
          "The number of cycles the CPU executes per second,
           measured in MHz (MegaHertz).";
      }
      leaf cores {
        type uint8;
        description
          "The number of independent CPU in a single computing
           component.";
      }
      leaf threads {
        type uint16;
        description
          "The number of total threads of the CPU";
      }
    }

    container memory {
      description
        "Memory (i.e., Random Access Memory (RAM)) specification of
         an NSF.";

      leaf capacity {
        type uint32;
        units "MB";
        description
          "The total memory capacity in Megabytes (MB).";
      }
      leaf speed {
        type uint32;
        units "MHz";
        description
          "The data transfer rate of the memory in MegaHertz (MHz).";
      }
    }

    container disk {
      description
        "Disk or storage specification of an NSF";

      leaf capacity {
        type uint32;
        units "MB";
        description
          "The disk or storage maximum capacity in Megabytes (MB).";
      }
    }

    container bandwidth {
      description
        "Network bandwidth available on an NSF
         in the unit of Bps (Bytes per second)";

      leaf outbound {
        type uint64;
        units "Bps";
        description
          "The maximum outbound network bandwidth available to the
           NSF in bytes per second (Bps)";
      }

      leaf inbound {
        type uint64;
        units "Bps";
        description
          "The maximum inbound network bandwidth available to the
           NSF in bytes per second (Bps)";
      }
    }
  }

  grouping nsf-access-info {
    description
      "Information required to access an NSF";
    leaf ip {
      type union {
        type inet:ip-address-no-zone;
        type inet:domain-name;
      }
      description
        "Either an IP (IPv4 or IPv6) address or the domain name of
         this NSF";
    }
    leaf port {
      type inet:port-number;
      description
        "Port available on this NSF";
    }
    leaf management-protocol {
      type enumeration {
        enum NETCONF {
          description
            "Represents the management protocol NETCONF";
          reference
            "RFC 6241: Network Configuration Protocol (NETCONF)";
        }
        enum RESTCONF {
          description
            "Represents the management protocol RESTCONF";
          reference
            "RFC 8040: RESTCONF Protocol";
        }
      }
      description
        "The management protocol used to manage the NSF";
    }
    leaf username {
      type string;
      description
        "The user name string identifying the credentials for the
         authentication.";
    }
    leaf password {
      type ianach:crypt-hash;
      description
        "The password for the username for the authentication.
         Any plain-text password must be converted to a hashed value
         as soon as possible";
    }
  }

  augment "/i2nsfcap:nsf" {
    description
      "Augmented information of an NSF's capability that DMS
       registers with Security Controller";
    reference
      "draft-ietf-i2nsf-capability-data-model-32: I2NSF Capability
       YANG Data Model";
    container nsf-specification {
      description
        "The specification of an NSF";
      uses nsf-specification;
    }
    container nsf-access-info {
      description
        "Network access information of this NSF";
      uses nsf-access-info;
    }
  }

  rpc nsf-capability-query {
    description
      "Description of the capabilities that the
       Security Controller requests to the DMS";
    input {
      container query-nsf-capability {
        description
          "Description of the capabilities to request";
        uses i2nsfcap:nsf-capabilities;
        reference "RFC YYYY: I2NSF Capability YANG Data Model";
      //RFC Ed.: replace YYYY with actual RFC number of
      //draft-ietf-i2nsf-capability-data-model and remove this note.
      }
    }
    output {
      container nsf-access-info {
        description
          "Network access information of an NSF
           with the requested capabilities";
        leaf nsf-name {
          type string;
          description
          "The name of this registered NSF. The NSF name MUST be
           unique to identify the NSF with the capability. The name
           can be an arbitrary string including Fully Qualified
           Domain Name (FQDN).";
        }
        uses nsf-access-info;
      }
    }
  }
}

<CODE ENDS>

6. 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-registration-interface
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-registration-interface
Namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-registration-interface
Prefix: i2nsfri
Reference: RFC XXXX

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

7. Security Considerations

The YANG module specified in this document defines a data schema designed to be accessed through network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the required secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the required secure transport is TLS [RFC8446].¶

The NETCONF access control model [RFC8341] provides a means of restricting access to specific NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.¶

The architecture of I2NSF Framework presents a risk to the implementation of security detection and mitigation activities. It is important to have an authentication and authorization method between the communication of the Security Controller and the DMS. The following are threats that need to be considered and mitigated:¶

Compromised DMS with valid credentials:

It can send falsified information to the Security Controller to mislead existing detection or mitigation devices. Currently, there is no in-framework mechanism to mitigate this, and it is an issue for such infrastructures. It is important to keep confidential information from unauthorized persons to mitigate the possibility of compromising the DMS with this information.¶

Impersonating DMS:

This involves a system trying to send false information while imitating as a DMS; client authentication would help the Security Controller to identify this invalid DMS.¶

The YANG module defined in this document extends the YANG module described in [I-D.ietf-i2nsf-capability-data-model]. Hence, this document shares all the security issues that are specified in Section 9 of [I-D.ietf-i2nsf-capability-data-model].¶

There are a number of extended data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes MAY be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:¶

• nsf-specification: The attacker may provide incorrect information of the specification of any target NSF by illegally modifying this.¶
• nsf-access-info: The attacker may provide incorrect network access information of any target NSF by illegally modifying this.¶

Some of the readable extended 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 and their sensitivity/vulnerability:¶

• nsf-specification: The attacker may gather the specification information of any target NSF and misuse the information for subsequent attacks.¶
• nsf-access-info: The attacker may gather the network access information of any target NSF and misuse the information for subsequent attacks.¶

The RPC operation in this YANG module MAY be considered sensitive or vulnerable in some network environments. It is thus important to control access to this operation. The following is the operation and its sensitivity/vulnerability:¶

• nsf-capability-query: The attacker may exploit this RPC operation to deteriorate the availability of the DMS and/or gather the information of some interested NSFs from the DMS. Some of the product capabilities provided by a vendor may be publicly known, the DMS should provide an authentication and authorization method to make sure this node cannot be used for exploitation.¶

Appendix A. XML Examples of an NSF Registration with I2NSF Registration Interface Data Model

This section shows XML examples of the I2NSF Registration Interface data model for registering the capabilities in either IPv4 networks [RFC5737] or IPv6 networks [RFC3849] with Security Controller.¶

<nsf
  xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-capability"
  xmlns:i2nsfri="urn:ietf:params:xml:ns:yang
                 :ietf-i2nsf-registration-interface">
  <nsf-name>ipv4_general_firewall</nsf-name>
  <condition-capabilities>
    <generic-nsf-capabilities>
      <ipv4-capability>next-header</ipv4-capability>
      <ipv4-capability>source-address</ipv4-capability>
      <ipv4-capability>destination-address</ipv4-capability>
      <tcp-capability>source-port-number</tcp-capability>
      <tcp-capability>destination-port-number</tcp-capability>
    </generic-nsf-capabilities>
  </condition-capabilities>
  <action-capabilities>
    <ingress-action-capability>pass</ingress-action-capability>
    <ingress-action-capability>drop</ingress-action-capability>
    <ingress-action-capability>mirror</ingress-action-capability>
    <egress-action-capability>pass</egress-action-capability>
    <egress-action-capability>drop</egress-action-capability>
    <egress-action-capability>mirror</egress-action-capability>
  </action-capabilities>
  <i2nsfri:nsf-specification>
    <i2nsfri:cpu>
      <i2nsfri:model>
        Intel(R) Core(TM) i7-10510U
      </i2nsfri:model>
      <i2nsfri:clock-speed>1800</i2nsfri:clock-speed>
      <i2nsfri:cores>4</i2nsfri:cores>
      <i2nsfri:threads>8</i2nsfri:threads>
    </i2nsfri:cpu>
    <i2nsfri:memory>
      <i2nsfri:capacity>8192</i2nsfri:capacity>
      <i2nsfri:speed>2667</i2nsfri:speed>
    </i2nsfri:memory>
    <i2nsfri:disk>
      <i2nsfri:capacity>239000</i2nsfri:capacity>
    </i2nsfri:disk>
    <i2nsfri:bandwidth>
      <i2nsfri:outbound>1000000000</i2nsfri:outbound>
      <i2nsfri:inbound>1000000000</i2nsfri:inbound>
    </i2nsfri:bandwidth>
  </i2nsfri:nsf-specification>
  <i2nsfri:nsf-access-info>
    <i2nsfri:ip>192.0.2.11</i2nsfri:ip>
    <i2nsfri:port>49152</i2nsfri:port>
    <i2nsfri:management-protocol>
      NETCONF
    </i2nsfri:management-protocol>
    <i2nsfri:username>alice</i2nsfri:username>
    <i2nsfri:password>$0$password123</i2nsfri:password>
  </i2nsfri:nsf-access-info>
</nsf>

Figure 8 shows the configuration XML for registering a general firewall in an IPv4 network [RFC5737] and its capabilities as follows.¶

1. The instance name of the NSF is ipv4_general_firewall.¶
2. The NSF can inspect IPv4 protocol header field, source address(es), and destination address(es).¶
3. The NSF can inspect the port number(s) for the transport layer protocol, i.e., TCP.¶
4. The NSF can determine whether the packets are allowed to pass, drop, or mirror.¶
5. The NSF's CPU model is Intel(R) Core(TM) i7-10510U. The clock speed is 1800 MHz, with 4 cores and 8 total threads.¶
6. The NSF's memory capacity is 8192 MB with the speed 2667 MHz.¶
7. The NSF's storage can hold maximum 239000 MB.¶
8. The network bandwidth available on the NSF is 1 GBps for both the outbound traffic and inbound traffic.¶
9. The IPv4 address of the NSF is 192.0.2.11.¶
10. The port of the NSF is 49152 using the NETCONF protocol. The credentials to access the NETCONF are "alice" as the username and "password123" for the password.¶

<nsf
  xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-capability"
  xmlns:i2nsfri="urn:ietf:params:xml:ns:yang
                 :ietf-i2nsf-registration-interface">
  <nsf-name>ipv6_general_firewall</nsf-name>
  <condition-capabilities>
    <generic-nsf-capabilities>
      <ipv6-capability>next-header</ipv6-capability>
      <ipv6-capability>source-address</ipv6-capability>
      <ipv6-capability>destination-address</ipv6-capability>
      <tcp-capability>source-port-number</tcp-capability>
      <tcp-capability>destination-port-number</tcp-capability>
    </generic-nsf-capabilities>
  </condition-capabilities>
  <action-capabilities>
    <ingress-action-capability>pass</ingress-action-capability>
    <ingress-action-capability>drop</ingress-action-capability>
    <ingress-action-capability>mirror</ingress-action-capability>
    <egress-action-capability>pass</egress-action-capability>
    <egress-action-capability>drop</egress-action-capability>
    <egress-action-capability>mirror</egress-action-capability>
  </action-capabilities>
  <i2nsfri:nsf-specification>
    <i2nsfri:cpu>
      <i2nsfri:model>
        Intel(R) Core(TM) i7-10510U
      </i2nsfri:model>
      <i2nsfri:clock-speed>1800</i2nsfri:clock-speed>
      <i2nsfri:cores>4</i2nsfri:cores>
      <i2nsfri:threads>8</i2nsfri:threads>
    </i2nsfri:cpu>
    <i2nsfri:memory>
      <i2nsfri:capacity>8192</i2nsfri:capacity>
      <i2nsfri:speed>2667</i2nsfri:speed>
    </i2nsfri:memory>
    <i2nsfri:disk>
      <i2nsfri:capacity>239000</i2nsfri:capacity>
    </i2nsfri:disk>
    <i2nsfri:bandwidth>
      <i2nsfri:outbound>1000000000</i2nsfri:outbound>
      <i2nsfri:inbound>1000000000</i2nsfri:inbound>
    </i2nsfri:bandwidth>
  </i2nsfri:nsf-specification>
  <i2nsfri:nsf-access-info>
    <i2nsfri:ip>2001:db8:0:1::11</i2nsfri:ip>
    <i2nsfri:port>49152</i2nsfri:port>
    <i2nsfri:management-protocol>
      NETCONF
    </i2nsfri:management-protocol>
    <i2nsfri:username>alice</i2nsfri:username>
    <i2nsfri:password>$0$password123</i2nsfri:password>
  </i2nsfri:nsf-access-info>
</nsf>

In addition, Figure 9 shows the configuration XML for registering a general firewall in an IPv6 network [RFC3849] and its capabilities as follows.¶

1. The instance name of the NSF is ipv6_general_firewall.¶
2. The NSF can inspect IPv6 next header, flow direction, source address(es), and destination address(es)¶
3. The NSF can inspect the port number(s) and flow direction for the transport layer protocol, i.e., TCP and UDP.¶
4. The NSF can determine whether the packets are allowed to pass, drop, or mirror.¶
5. The NSF's CPU model is Intel(R) Core(TM) i7-10510U. The clock speed is 1800 MHz, with 4 cores and 8 total threads.¶
6. The NSF's memory capacity is 8192 MB with the speed 2667 MHz.¶
7. The NSF's storage can hold maximum 239 GB.¶
8. The network bandwidth available on the NSF is 1 GBps for both the outbound and inbound traffics.¶
9. The IPv6 address of the NSF is 2001:db8:0:1::11.¶
10. The port of the NSF is 49152 using the NETCONF protocol. The credentials to access the NETCONF are "alice" as the username and "password123" for the password.¶

Appendix B. XML Examples of an NSF Query with I2NSF Registration Interface Data Model

This section shows an XML example of the Security Controller requesting an additional NSF with a certain capability. In this example, an I2NSF User requests a security service that is able to block the specified websites. When the Security Controller checks that no registered NSF can provide such a service, it makes a query to the DMS with the following XML:¶

<rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <nsf-capability-query
  xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-registration-interface">
    <query-nsf-capability>
      <condition-capabilities>
        <advanced-nsf-capabilities>
          <url-filtering-capability>
            user-defined
          </url-filtering-capability>
        </advanced-nsf-capabilities>
      </condition-capabilities>
      <action-capabilities>
        <ingress-action-capability>drop</ingress-action-capability>
        <egress-action-capability>drop</egress-action-capability>
      </action-capabilities>
    </query-nsf-capability>
  </nsf-capability-query>
</rpc>

Figure 10 shows the XML for requesting an unregistered web filter with its capabilities as follows.¶

1. The NSF can inspect a URL matched from a user-defined URL where the user can specify their own URL.¶
2. The NSF can control the network by dropping the packets that match the condition. It can drop packets that are entering or leaving the target network.¶

After receiving a query given in Figure 10, the DMS can reply with following XML:¶

<rpc-reply message-id="101"
          xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <nsf-access-info
  xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-registration-interface">
    <nsf-name>web_filter</nsf-name>
    <ip>192.0.2.13</ip>
    <port>49152</port>
    <management-protocol>NETCONF</management-protocol>
    <username>alice</username>
    <password>$0$password123</password>
  </nsf-access-info>
</rpc-reply>

In the reply shown in Figure 11, the additional NSF called web_filter can be used by accessing the NSF with the IPv4 address of 192.0.2.13 and the port number of 49152, using the NETCONF management protocol. The credentials to access the NETCONF are "alice" as the username and "password123" for the password.¶

Appendix C. NSF Lifecycle Management in NFV Environments

Network Functions Virtualization (NFV) can be used to implement I2NSF framework. In NFV environments, NSFs are deployed as virtual network functions (VNFs). Security Controller can be implemented as an Element Management (EM) of the NFV architecture, and is connected with the VNF Manager (VNFM) via the Ve-Vnfm interface [nfv-framework]. Security Controller can use this interface for the purpose of the lifecycle management of NSFs. If some NSFs need to be instantiated to enforce security policies in the I2NSF framework, Security Controller could request the VNFM to instantiate them through the Ve-Vnfm interface. Or if an NSF, running as a VNF, is not used by any traffic flows for a time period, Security Controller MAY request deinstantiating it through the interface for efficient resource utilization.¶

Appendix D. 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, Reshad Rahman (YANG doctor), and Tom Petch. We 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) (No. 2016-0-00078, Cloud Based Security Intelligence Technology Development for the Customized Security Service Provisioning). This work was supported in part by the IITP (2020-0-00395-003, Standard Development of Blockchain based Network Management Automation Technology).¶

Appendix E. Contributors

The following are co-authors of this document:¶

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¶

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

Susan Hares - Huawei, 7453 Hickory Hill, Saline, MI 48176, USA. EMail: shares@ndzh.com¶

Diego R. Lopez - Telefonica I+D, Jose Manuel Lara, 9, Seville, 41013, Spain. EMail: diego.r.lopez@telefonica.com¶

Appendix F. Changes from draft-ietf-i2nsf-registration-interface-dm-21

The following changes are made from draft-ietf-i2nsf-registration-interface-dm-21:¶

• The updates are made with the comments from AD Roman Danyliw.¶

Authors' Addresses