Network Working Group                                           D. Fedyk
Internet-Draft                                                  C. Hopps
Intended status: Standards Track                 LabN Consulting, L.L.C.
Expires: 15 May 2022                                    11 November 2021


             A YANG Data Model for IP Traffic Flow Security
                    draft-ietf-ipsecme-yang-iptfs-03

Abstract

   This document describes a yang module for the management of IP
   Traffic Flow Security additions to IKEv2 and IPsec.

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 15 May 2022.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.







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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology & Concepts  . . . . . . . . . . . . . . . . .   3
   2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  YANG Management . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  YANG Tree . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
     4.1.  Updates to the IETF XML Registry  . . . . . . . . . . . .  19
     4.2.  Updates to the YANG Module Names Registry . . . . . . . .  19
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  20
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  20
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  20
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  20
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  21
   Appendix A.  Examples . . . . . . . . . . . . . . . . . . . . . .  22
     A.1.  Example XML Configuration . . . . . . . . . . . . . . . .  22
     A.2.  Example XML Operational Data  . . . . . . . . . . . . . .  23
     A.3.  Example JSON Configuration  . . . . . . . . . . . . . . .  24
     A.4.  Example JSON Operational Data . . . . . . . . . . . . . .  26
     A.5.  Example JSON Operational Statistics . . . . . . . . . . .  27
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  28

1.  Introduction

   This document defines a YANG module [RFC7950] for the management of
   the IP Traffic Flow Security (IP-TFS) extensions as defined in
   [I-D.ietf-ipsecme-iptfs].  IP-TFS provides enhancements to an IPsec
   tunnel Security Association to provide improved traffic
   confidentiality.  Traffic confidentiality reduces the ability of
   traffic analysis to determine identity and correlate observable
   traffic patterns.  IP-TFS offers efficiency when aggregating traffic
   in fixed size IPsec tunnel packets.

   The YANG data model in this document conforms to the Network
   Management Datastore Architecture (NMDA) defined in [RFC8342].

   The published YANG modules for IPsec are defined in [RFC9061].  This
   document uses these models as a general IPsec model that is augmented
   for IP-TFS.  The models in [RFC9061] provide for both an IKE and an
   IKELESS model.









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1.1.  Terminology & Concepts

   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
   [RFC2119] [RFC8174] when, and only when, they appear in all capitals,
   as shown here.

2.  Overview

   This document defines configuration and operational parameters of IP
   traffic flow security (IP-TFS).  IP-TFS, defined in
   [I-D.ietf-ipsecme-iptfs], defines a security association for tunnel
   mode IPsec with characteristics that improve traffic confidentiality
   and reduce bandwidth efficiency loss.  These documents assume
   familiarity with IP security concepts described in [RFC4301].

   IP-TFS uses tunnel mode to improve confidentiality by hiding inner
   packet identifiable information, packet size and packet timing.  IP-
   TFS provides a general capability allowing aggregation of multiple
   packets in uniform size outer tunnel ipsec packets.  It maintains the
   outer packet size by utilizing combinations of aggregating, padding
   and fragmenting inner packets to fll out the IPsec outer tunnel
   packet.  Zero byte padding is used to fill the packet when no data is
   available to send.

   This document specifies an extensible configuration model for IP-TFS.
   This version utilizes the capabilities of IP-TFS to configure fixed
   size IP-TFS Packets that are transmitted at a constant rate.  This
   model is structured to allow for different types of operation through
   future augmentation.

   IP-TFS YANG augments IPsec YANG model from [RFC9061].  IP-TFS makes
   use of IPsec tunnel mode and adds a small number configuration items
   to tunnel mode IPsec.  As defined in [I-D.ietf-ipsecme-iptfs], any SA
   configured to use IP-TFS supports only IP-TFS packets i.e. no mixed
   IPsec modes.

   The behavior for IP-TFS is controlled by the source.  The self-
   describing format of an IP-TFS packets allows a sending side to
   adjust the packet-size and timing independently from any receiver.
   Both directions are also independent, e.g.  IP-TFS may be run only in
   one direction.  This means that counters, which are created here for
   both directions may be 0 or not updated in the case of an SA that
   uses IP-TFS only in on direction.

   Cases where IP-TFS statistics are active for one direction:




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   *  SA one direction - IP-TFS enabled

   *  SA both directions - IP-TFS only enabled in one direction

   Case where IP-TFS statistics are for both directions:

   *  SA both directions - IP-TFS enable for both directions

   The IP-TFS model support IP-TFS configuration and operational data.

   This YANG module supports configuration of fixed size and fixed rate
   packets, and elements that may be augmented to support future
   configuration.  The protocol specification [I-D.ietf-ipsecme-iptfs],
   goes beyond this simple fixed mode of operation by defining a general
   format for any type of scheme.  In this document the outer IPsec
   packets can be sent with fixed or variable size (without padding).
   The configuration allows the fixed packet size to be determined by
   the path MTU.  The fixed packet size can also be configured if a
   value lower than the path MTU is desired.

   Other configuration items include:

   *  Congestion Control.  A congestion control setting to allow IP-TFS
      to reduce the packet rate when congestion is detected.

   *  Fixed Rate configuration.  The IP-TFS tunnel rate can be
      configured taking into account either layer 2 overhead or layer 3
      overhead.  Layer 3 overhead is the IP data rate and layer 2
      overhead is the rate of bits on the link.  The combination of
      packet size and rate determines the nominal maximum bandwidth and
      the transmission interval when fixed size packets are used.

   *  User packet Fragmentation Control.  While fragmentation is
      recommended for improved efficiency, a configuration is provided
      if users wish to observe the effect no-fragmentation on their data
      flows.

   The YANG operational data allows the readout of the configured
   parameters as well as the per SA statistics and error counters for
   IP-TFS.  Per SA IPsec packet statistics are provided as a feature and
   per SA IP-TFS specific statistics as another feature.  Both sets of
   statistics augment the IPsec YANG models with counters that allow
   observation of IP-TFS packet efficiency.

   RFC [RFC9061] has a set of IPsec YANG management objects.  IP-TFS
   YANG augments the IKE and the IKELESS models.  In these models the
   Security Policy database entry and Security Association entry for an
   IPsec Tunnel can be augmented with IP-TFS.



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3.  YANG Management

3.1.  YANG Tree

   The following is the YANG tree diagram ([RFC8340]) for the IP-TFS
   extensions.

   module: ietf-ipsec-iptfs
     augment /nsfike:ipsec-ike/nsfike:conn-entry/nsfike:spd
               /nsfike:spd-entry/nsfike:ipsec-policy-config
               /nsfike:processing-info/nsfike:ipsec-sa-cfg:
       +--rw traffic-flow-security
          +--rw congestion-control?           boolean
          +--rw packet-size
          |  +--rw use-path-mtu-discovery?   boolean
          |  +--rw outer-packet-size?        uint16
          +--rw (tunnel-rate)?
          |  +--:(l2-fixed-rate)
          |  |  +--rw l2-fixed-rate?          yang:counter64
          |  +--:(l3-fixed-rate)
          |     +--rw l3-fixed-rate?          yang:counter64
          +--rw dont-fragment?                boolean
          +--rw max-aggregation-time?         decimal64
          +--rw window-size?                  uint16
          +--rw send-immediately?             boolean
          +--rw lost-packet-timer-interval?   decimal64
     augment /nsfike:ipsec-ike/nsfike:conn-entry/nsfike:child-sa-info:
       +--ro traffic-flow-security
          +--ro congestion-control?           boolean
          +--ro packet-size
          |  +--ro use-path-mtu-discovery?   boolean
          |  +--ro outer-packet-size?        uint16
          +--ro (tunnel-rate)?
          |  +--:(l2-fixed-rate)
          |  |  +--ro l2-fixed-rate?          yang:counter64
          |  +--:(l3-fixed-rate)
          |     +--ro l3-fixed-rate?          yang:counter64
          +--ro dont-fragment?                boolean
          +--ro max-aggregation-time?         decimal64
          +--ro window-size?                  uint16
          +--ro send-immediately?             boolean
          +--ro lost-packet-timer-interval?   decimal64
     augment /nsfikels:ipsec-ikeless/nsfikels:spd/nsfikels:spd-entry
               /nsfikels:ipsec-policy-config/nsfikels:processing-info
               /nsfikels:ipsec-sa-cfg:
       +--rw traffic-flow-security
          +--rw congestion-control?           boolean
          +--rw packet-size



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          |  +--rw use-path-mtu-discovery?   boolean
          |  +--rw outer-packet-size?        uint16
          +--rw (tunnel-rate)?
          |  +--:(l2-fixed-rate)
          |  |  +--rw l2-fixed-rate?          yang:counter64
          |  +--:(l3-fixed-rate)
          |     +--rw l3-fixed-rate?          yang:counter64
          +--rw dont-fragment?                boolean
          +--rw max-aggregation-time?         decimal64
          +--rw window-size?                  uint16
          +--rw send-immediately?             boolean
          +--rw lost-packet-timer-interval?   decimal64
     augment /nsfikels:ipsec-ikeless/nsfikels:sad/nsfikels:sad-entry:
       +--ro traffic-flow-security
          +--ro congestion-control?           boolean
          +--ro packet-size
          |  +--ro use-path-mtu-discovery?   boolean
          |  +--ro outer-packet-size?        uint16
          +--ro (tunnel-rate)?
          |  +--:(l2-fixed-rate)
          |  |  +--ro l2-fixed-rate?          yang:counter64
          |  +--:(l3-fixed-rate)
          |     +--ro l3-fixed-rate?          yang:counter64
          +--ro dont-fragment?                boolean
          +--ro max-aggregation-time?         decimal64
          +--ro window-size?                  uint16
          +--ro send-immediately?             boolean
          +--ro lost-packet-timer-interval?   decimal64
     augment /nsfike:ipsec-ike/nsfike:conn-entry/nsfike:child-sa-info:
       +--ro ipsec-stats {ipsec-stats}?
       |  +--ro tx-pkts?        yang:counter64
       |  +--ro tx-octets?      yang:counter64
       |  +--ro tx-drop-pkts?   yang:counter64
       |  +--ro rx-pkts?        yang:counter64
       |  +--ro rx-octets?      yang:counter64
       |  +--ro rx-drop-pkts?   yang:counter64
       +--ro iptfs-inner-pkt-stats {iptfs-stats}?
       |  +--ro tx-pkts?              yang:counter64
       |  +--ro tx-octets?            yang:counter64
       |  +--ro rx-pkts?              yang:counter64
       |  +--ro rx-octets?            yang:counter64
       |  +--ro rx-incomplete-pkts?   yang:counter64
       +--ro iptfs-outer-pkt-stats {iptfs-stats}?
          +--ro tx-all-pad-pkts?       yang:counter64
          +--ro tx-all-pad-octets?     yang:counter64
          +--ro tx-extra-pad-pkts?     yang:counter64
          +--ro tx-extra-pad-octets?   yang:counter64
          +--ro rx-all-pad-pkts?       yang:counter64



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          +--ro rx-all-pad-octets?     yang:counter64
          +--ro rx-extra-pad-pkts?     yang:counter64
          +--ro rx-extra-pad-octets?   yang:counter64
          +--ro rx-errored-pkts?       yang:counter64
          +--ro rx-missed-pkts?        yang:counter64
     augment /nsfikels:ipsec-ikeless/nsfikels:sad/nsfikels:sad-entry:
       +--rw ipsec-stats {ipsec-stats}?
       |  +--ro tx-pkts?        yang:counter64
       |  +--ro tx-octets?      yang:counter64
       |  +--ro tx-drop-pkts?   yang:counter64
       |  +--ro rx-pkts?        yang:counter64
       |  +--ro rx-octets?      yang:counter64
       |  +--ro rx-drop-pkts?   yang:counter64
       +--ro iptfs-inner-pkt-stats {iptfs-stats}?
       |  +--ro tx-pkts?              yang:counter64
       |  +--ro tx-octets?            yang:counter64
       |  +--ro rx-pkts?              yang:counter64
       |  +--ro rx-octets?            yang:counter64
       |  +--ro rx-incomplete-pkts?   yang:counter64
       +--ro iptfs-outer-pkt-stats {iptfs-stats}?
          +--ro tx-all-pad-pkts?       yang:counter64
          +--ro tx-all-pad-octets?     yang:counter64
          +--ro tx-extra-pad-pkts?     yang:counter64
          +--ro tx-extra-pad-octets?   yang:counter64
          +--ro rx-all-pad-pkts?       yang:counter64
          +--ro rx-all-pad-octets?     yang:counter64
          +--ro rx-extra-pad-pkts?     yang:counter64
          +--ro rx-extra-pad-octets?   yang:counter64
          +--ro rx-errored-pkts?       yang:counter64
          +--ro rx-missed-pkts?        yang:counter64

3.2.  YANG Module

   The following is the YANG module for managing the IP-TFS extensions.
   The model contains references to [I-D.ietf-ipsecme-iptfs] and
   [RFC5348].

   <CODE BEGINS> file "ietf-ipsec-iptfs@2021-11-11.yang"
   module ietf-ipsec-iptfs {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs";
     prefix iptfs;

     import ietf-i2nsf-ike {
       prefix nsfike;
     }
     import ietf-i2nsf-ikeless {
       prefix nsfikels;



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     }
     import ietf-yang-types {
       prefix yang;
     }

     organization
       "IETF IPSECME Working Group (IPSECME)";
     contact
       "WG Web:  <https://tools.ietf.org/wg/ipsecme/>
        WG List: <mailto:ipsecme@ietf.org>

        Author: Don Fedyk
                <mailto:dfedyk@labn.net>

        Author: Christian Hopps
                <mailto:chopps@chopps.org>";

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

     description
       "This module defines the configuration and operational state for
        managing the IP Traffic Flow Security functionality [RFC XXXX].

        Copyright (c) 2021 IETF Trust and the persons identified as
        authors of the code. All rights reserved.

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

        This version of this YANG module is part of RFC XXXX
        (https://tools.ietf.org/html/rfcXXXX); see the RFC itself for
        full legal notices.";

     revision 2021-11-11 {
       description
         "Initial Revision";
       reference
         "RFC XXXX: IP Traffic Flow Security YANG Module";
     }

     feature ipsec-stats {
       description
         "This feature indicates the device supports



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          per SA IPsec statistics";
     }

     feature iptfs-stats {
       description
         "This feature indicates the device supports
          per SA IP Traffic Flow Security statistics";
     }

     /*--------------------*/
     /*   groupings        */
     /*--------------------*/

     grouping ipsec-tx-stat-grouping {
       description
         "IPsec outbound statistics";
       leaf tx-pkts {
         type yang:counter64;
         config false;
         description
           "Outbound Packet count";
       }
       leaf tx-octets {
         type yang:counter64;
         config false;
         description
           "Outbound Packet bytes";
       }
       leaf tx-drop-pkts {
         type yang:counter64;
         config false;
         description
           "Outbound dropped packets count";
       }
     }

     grouping ipsec-rx-stat-grouping {
       description
         "IPsec inbound statistics";
       leaf rx-pkts {
         type yang:counter64;
         config false;
         description
           "Inbound Packet count";
       }
       leaf rx-octets {
         type yang:counter64;
         config false;



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         description
           "Inbound Packet bytes";
       }
       leaf rx-drop-pkts {
         type yang:counter64;
         config false;
         description
           "Inbound dropped packets count";
       }
     }

     grouping iptfs-inner-tx-stat-grouping {
       description
         "IP-TFS outbound inner packet statistics";
       leaf tx-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of IP-TFS inner packets sent. This
            count is whole packets only.  A fragmented packet
            counts as one packet";
         reference
           "draft-ietf-ipsecme-iptfs";
       }
       leaf tx-octets {
         type yang:counter64;
         config false;
         description
           "Total number of IP-TFS inner octets sent.  This is
            inner packet octets only.  Does not count padding.";
         reference
           "draft-ietf-ipsecme-iptfs";
       }
     }

     grouping iptfs-outer-tx-stat-grouping {
       description
         "IP-TFS outbound inner packet statistics";
       leaf tx-all-pad-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of transmitted IP-TFS packets that
            were all padding with no inner packet data.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3";
       }
       leaf tx-all-pad-octets {



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         type yang:counter64;
         config false;
         description
           "Total number transmitted octets of padding added to
            IP-TFS packets with no inner packet data.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3";
       }
       leaf tx-extra-pad-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of transmitted outer IP-TFS packets
            that included some padding.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3.1";
       }
       leaf tx-extra-pad-octets {
         type yang:counter64;
         config false;
         description
           "Total number of transmitted octets of padding added
            to outer IP-TFS packets with data.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3.1";
       }
     }

     grouping iptfs-inner-rx-stat-grouping {
       description
         "IP-TFS inner packet inbound statistics";
       leaf rx-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of IP-TFS inner packets received.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2";
       }
       leaf rx-octets {
         type yang:counter64;
         config false;
         description
           "Total number of IP-TFS inner octets received.  Does
            not include padding or overhead";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2";
       }



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       leaf rx-incomplete-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of IP-TFS inner packets that were
            incomplete.  Usually this is due to fragments not
            received. Also, this may be due to misordering or
            errors in received outer packets.";
         reference
           "draft-ietf-ipsecme-iptfs";
       }
     }

     grouping iptfs-outer-rx-stat-grouping {
       description
         "IP-TFS outer packet inbound statistics";
       leaf rx-all-pad-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of received IP-TFS packets that were
            all padding with no inner packet data.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3";
       }
       leaf rx-all-pad-octets {
         type yang:counter64;
         config false;
         description
           "Total number received octets of padding added to
            IP-TFS packets with no inner packet data.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3";
       }
       leaf rx-extra-pad-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of received outer IP-TFS packets that
            included some padding.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3.1";
       }
       leaf rx-extra-pad-octets {
         type yang:counter64;
         config false;
         description
           "Total number of received octets of padding added to



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            outer IP-TFS packets with data.";
         reference
           "draft-ietf-ipsecme-iptfs section 2.2.3.1";
       }
       leaf rx-errored-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of IP-TFS outer packets dropped due to
            errors.";
         reference
           "draft-ietf-ipsecme-iptfs";
       }
       leaf rx-missed-pkts {
         type yang:counter64;
         config false;
         description
           "Total number of IP-TFS outer packets missing
            indicated by missing sequence number.";
         reference
           "draft-ietf-ipsecme-iptfs";
       }
     }

     grouping iptfs-config {
       description
         "This is the grouping for iptfs configuration";
       container traffic-flow-security {
         description
           "Configure the IPSec TFS in Security
            Association Database (SAD)";
         leaf congestion-control {
           type boolean;
           default "true";
           description
             "When set to true, the default, this enables the
              congestion control on-the-wire exchange of data that is
              required by congestion control algorithms as defined by
              RFC 5348.  When set to false, IP-TFS sends fixed-sized
              packets over an IP-TFS tunnel at a constant rate.";
           reference
             "draft-ietf-ipsecme-iptfs section 2.5.2, RFC 5348";
         }
         container packet-size {
           description
             "Packet size is either auto-discovered or manually
              configured.";
           leaf use-path-mtu-discovery {



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             type boolean;
             default "true";
             description
               "Utilize path mtu discovery to determine maximum
                IP-TFS packet size. If the packet size is explicitly
                configured, then it will only be adjusted downward if
                use-path-mtu-discovery is set.";
             reference
               "draft-ietf-ipsecme-iptfs section 4.2";
           }
           leaf outer-packet-size {
             type uint16;
             description
               "The size of the outer encapsulating tunnel packet (i.e.,
                the IP packet containing the ESP payload).";
             reference
               "draft-ietf-ipsecme-iptfs section 4.2";
           }
         }
         choice tunnel-rate {
           description
             "TFS bit rate may be specified at layer 2 wire
              rate or layer 3 packet rate";
           leaf l2-fixed-rate {
             type yang:counter64;
             description
               "Target bandwidth/bit rate in bps for iptfs tunnel.
                This fixed rate is the nominal timing for the fixed
                size packet.  If congestion control is enabled the
                rate may be adjusted down (or up if unset).";
             reference
               "draft-ietf-ipsecme-iptfs section 4.1";
           }
           leaf l3-fixed-rate {
             type yang:counter64;
             description
               "Target bandwidth/bit rate in bps for iptfs tunnel.
                This fixed rate is the nominal timing for the fixed
                size packet.  If congestion control is enabled the
                rate may be adjusted down (or up if unset).";
             reference
               "draft-ietf-ipsecme-iptfs section 4.1";
           }
         }
         leaf dont-fragment {
           type boolean;
           default "false";
           description



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             "Disable packet fragmentation across consecutive iptfs
              tunnel packets";
           reference
             "draft-ietf-ipsecme-iptfs section 2.2.4 and 6.4.1";
         }
         leaf max-aggregation-time {
           type decimal64 {
             fraction-digits 6;
           }
           units "milliseconds";
           description
             "Maximum aggregation time is the maximum length of time
              a received inner packet can be held prior to
              transmission in the iptfs tunnel. Inner packets that
              would be held longer than this time, based on the
              current tunnel configuration will be dropped rather
              than be queued for transmission.  Maximum aggregation
              time is configurable in milliseconds or fractional
              milliseconds down to 1 nanosecond.";
         }
         leaf window-size {
           type uint16 {
             range "0..65535";
           }
           description
             "The maximum number of out-of-order packets that will be
              reordered by an iptfs receiver while performing the
              reordering operation. The value 0 disables any
              reordering.";
           reference
             "draft-ietf-ipsecme-iptfs section 2.2.3";
         }
         leaf send-immediately {
           type boolean;
           default false;
           description
             "Send inner packets as soon as possible, do not wait for
              lost or misordered outer packets.  Selecting this
              option reduces the inner (user) packet delay but can
              amplify out-of-order delivery of the inner packet
              stream in the presence of packet aggregation and any
              reordering.";
           reference
             "draft-ietf-ipsecme-iptfs section 2.5";
         }
         leaf lost-packet-timer-interval {
           type decimal64 {
             fraction-digits 6;



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           }
           units "milliseconds";
           description
             "This interval defines the length of time an iptfs
              receiver will wait for a missing packet before
              considering it lost. Setting this value too low can
              impact reordering and reassembly. The value is
              configurable in milliseconds or fractional milliseconds
              down to 1 nanosecond.";
            reference
             "draft-ietf-ipsecme-iptfs section 2.2.3";
         }
       }
     }

     /*
      * IP-TFS ike configuration
      */

     augment "/nsfike:ipsec-ike/nsfike:conn-entry/nsfike:spd/"
           + "nsfike:spd-entry/"
           + "nsfike:ipsec-policy-config/"
           + "nsfike:processing-info/"
           + "nsfike:ipsec-sa-cfg" {
       description
         "IP-TFS configuration for this policy.";
       uses iptfs-config;
     }

     augment "/nsfike:ipsec-ike/nsfike:conn-entry/"
           + "nsfike:child-sa-info" {
       description
         "IP-TFS configured on this SA.";
       uses iptfs-config {
         refine "traffic-flow-security" {
           config false;
         }
       }
     }

     /*
      * IP-TFS ikeless configuration
      */

     augment "/nsfikels:ipsec-ikeless/nsfikels:spd/"
           + "nsfikels:spd-entry/"
           + "nsfikels:ipsec-policy-config/"
           + "nsfikels:processing-info/"



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           + "nsfikels:ipsec-sa-cfg" {
       description
         "IP-TFS configuration for this policy.";
       uses iptfs-config;
     }

     augment "/nsfikels:ipsec-ikeless/nsfikels:sad/"
           + "nsfikels:sad-entry" {
       description
         "IP-TFS configured on this SA.";
       uses iptfs-config {
         refine "traffic-flow-security" {
           config false;
         }
       }
     }

     /*
      * packet counters
      */

     augment "/nsfike:ipsec-ike/nsfike:conn-entry/"
           + "nsfike:child-sa-info" {
       description
         "Per SA Counters";
       container ipsec-stats {
         if-feature "ipsec-stats";
         config false;
         description
           "IPsec per SA packet counters.";
         uses ipsec-tx-stat-grouping {
           //when "direction = 'outbound'";
         }
         uses ipsec-rx-stat-grouping {
           //when "direction = 'inbound'";
         }
       }
       container iptfs-inner-pkt-stats {
         if-feature "iptfs-stats";
         config false;
         description
           "IPTFS per SA inner packet counters.";
         uses iptfs-inner-tx-stat-grouping {
           //when "direction = 'outbound'";
         }
         uses iptfs-inner-rx-stat-grouping {
           //when "direction = 'inbound'";
         }



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       }
       container iptfs-outer-pkt-stats {
         if-feature "iptfs-stats";
         config false;
         description
           "IPTFS per SA outer packets counters.";
         uses iptfs-outer-tx-stat-grouping {
           //when "direction = 'outbound'";
         }
         uses iptfs-outer-rx-stat-grouping {
           //when "direction = 'inbound'";
         }
       }
     }

     /*
      * packet counters
      */

     augment "/nsfikels:ipsec-ikeless/nsfikels:sad/"
           + "nsfikels:sad-entry" {
       description
         "Per SA Counters";
       container ipsec-stats {
         if-feature "ipsec-stats";
         description
           "IPsec per SA packet counters.";
         uses ipsec-tx-stat-grouping {
           //when "direction = 'outbound'";
         }
         uses ipsec-rx-stat-grouping {
           //when "direction = 'inbound'";
         }
       }
       container iptfs-inner-pkt-stats {
         if-feature "iptfs-stats";
         config false;
         description
           "IPTFS per SA inner packet counters.";
         uses iptfs-inner-tx-stat-grouping {
           //when "direction = 'outbound'";
         }
         uses iptfs-inner-rx-stat-grouping {
           //when "direction = 'inbound'";
         }
       }
       container iptfs-outer-pkt-stats {
         if-feature "iptfs-stats";



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         config false;
         description
           "IPTFS per SA outer packets counters.";
         uses iptfs-outer-tx-stat-grouping {
           //when "direction = 'outbound'";
         }
         uses iptfs-outer-rx-stat-grouping {
           //when "direction = 'inbound'";
         }
       }

     }
   }
   <CODE ENDS>

4.  IANA Considerations

4.1.  Updates to the IETF XML Registry

   This document registers a URI in the "IETF XML Registry" [RFC3688].
   Following the format in [RFC3688], the following registration has
   been made:

   URI:
      urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs

   Registrant Contact:
      The IESG.

   XML:
      N/A; the requested URI is an XML namespace.

4.2.  Updates to the YANG Module Names Registry

   This document registers one YANG module in the "YANG Module Names"
   registry [RFC6020].  Following the format in [RFC6020], the following
   registration has been made:

   name:
      ietf-ipsec-iptfs

   namespace:
      urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs

   prefix:
      iptfs





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   reference:
      RFC XXXX (RFC Ed.: replace XXXX with actual RFC number and remove
      this note.)

5.  Security Considerations

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

   The Network Configuration Access Control Model (NACM) [RFC8341]
   provides the means to restrict access for particular NETCONF or
   RESTCONF users to a preconfigured subset of all available NETCONF or
   RESTCONF protocol operations and content.

   The YANG module defined in this document can enable, disable and
   modify the behavior of IP traffic flow security, for the implications
   regarding these types of changes consult the [I-D.ietf-ipsecme-iptfs]
   which defines the functionality.

6.  Acknowledgements

   The authors would like to thank Eric Kinzie and Juergen Schoenwaelder
   for their feedback and review on the YANG model.

7.  References

7.1.  Normative References

   [I-D.ietf-ipsecme-iptfs]
              Hopps, C., "IP-TFS: Aggregation and Fragmentation Mode for
              ESP and its Use for IP Traffic Flow Security", Work in
              Progress, Internet-Draft, draft-ietf-ipsecme-iptfs-12, 8
              November 2021, <https://www.ietf.org/archive/id/draft-
              ietf-ipsecme-iptfs-12.txt>.

   [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>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.



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   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [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>.

   [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>.

   [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>.

   [RFC9061]  Marin-Lopez, R., Lopez-Millan, G., and F. Pereniguez-
              Garcia, "A YANG Data Model for IPsec Flow Protection Based
              on Software-Defined Networking (SDN)", RFC 9061,
              DOI 10.17487/RFC9061, July 2021,
              <https://www.rfc-editor.org/info/rfc9061>.

7.2.  Informative References

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

   [RFC5348]  Floyd, S., Handley, M., Padhye, J., and J. Widmer, "TCP
              Friendly Rate Control (TFRC): Protocol Specification",
              RFC 5348, DOI 10.17487/RFC5348, September 2008,
              <https://www.rfc-editor.org/info/rfc5348>.

   [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>.

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




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   [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>.

   [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>.

Appendix A.  Examples

   The following examples show configuration and operational data for
   the ikeless and ike cases using xml and json.  Also, the operational
   statistics for the ikeless case is illustrated.

A.1.  Example XML Configuration

   This example illustrates configuration for IP-TFS in the ikeless
   case.  Note that since this augments the ipsec ikeless schema only
   minimal a ikeless configuration to satisfy the schema has been
   populated.


























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   <i:ipsec-ikeless
     xmlns:i="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless"
     xmlns:tfs="urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs">
     <i:spd>
       <i:spd-entry>
         <i:name>protect-policy-1</i:name>
         <i:direction>outbound</i:direction>
         <i:ipsec-policy-config>
           <i:traffic-selector>
             <i:local-prefix>192.0.2.0/16</i:local-prefix>
             <i:remote-prefix>198.51.100.0/16</i:remote-prefix>
           </i:traffic-selector>
           <i:processing-info>
             <i:action>protect</i:action>
             <i:ipsec-sa-cfg>
               <tfs:traffic-flow-security>
                <tfs:congestion-control>true</tfs:congestion-control>
                 <tfs:packet-size>
                   <tfs:use-path-mtu-discovery
                      >true</tfs:use-path-mtu-discovery>
                 </tfs:packet-size>
                 <tfs:l2-fixed-rate>1000000000</tfs:l2-fixed-rate>
                 <tfs:max-aggregation-time
                    >0.1</tfs:max-aggregation-time>
                 <tfs:window-size>5</tfs:window-size>
                 <tfs:send-immediately>false</tfs:send-immediately>
                 <tfs:lost-packet-timer-interval
                    >0.2</tfs:lost-packet-timer-interval>
               </tfs:traffic-flow-security>
             </i:ipsec-sa-cfg>
           </i:processing-info>
         </i:ipsec-policy-config>
       </i:spd-entry>
     </i:spd>
   </i:ipsec-ikeless>

                 Figure 1: Example IP-TFS XML configuration

A.2.  Example XML Operational Data

   This example illustrates operational data for IP-TFS in the ikeless
   case.  Note that since this augments the ipsec ikeless schema only
   minimal ikeless configuration to satisfy the schema has been
   populated.







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   <i:ipsec-ikeless
     xmlns:i="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless"
     xmlns:tfs="urn:ietf:params:xml:ns:yang:ietf-ipsec-iptfs">
     <i:sad>
       <i:sad-entry>
         <i:name>sad-1</i:name>
         <i:ipsec-sa-config>
           <i:spi>1</i:spi>
           <i:traffic-selector>
             <i:local-prefix>2001:DB8::0/16</i:local-prefix>
             <i:remote-prefix>2001:DB8::1:0/16</i:remote-prefix>
           </i:traffic-selector>
         </i:ipsec-sa-config>
         <tfs:traffic-flow-security>
           <tfs:congestion-control>true</tfs:congestion-control>
           <tfs:packet-size>
             <tfs:use-path-mtu-discovery
               >true</tfs:use-path-mtu-discovery>
           </tfs:packet-size>
           <tfs:l2-fixed-rate>1000000000</tfs:l2-fixed-rate>
           <tfs:max-aggregation-time>0.100</tfs:max-aggregation-time>
           <tfs:window-size>0</tfs:window-size>
           <tfs:send-immediately>true</tfs:send-immediately>
           <tfs:lost-packet-timer-interval
             >0.200</tfs:lost-packet-timer-interval>
         </tfs:traffic-flow-security>
       </i:sad-entry>
     </i:sad>
   </i:ipsec-ikeless>

               Figure 2: Example IP-TFS XML Operational data

A.3.  Example JSON Configuration

   This example illustrates config data for IP-TFS in the ike case.
   Note that since this augments the ipsec ike schema only minimal ike
   configuration to satisfy the schema has been populated.

   {
     "ietf-i2nsf-ike:ipsec-ike": {
       "ietf-i2nsf-ike:conn-entry": [
         {
           "name": "my-peer-connection",
           "ike-sa-encr-alg": [
             {
               "id": 1,
               "algorithm-type": 12,
               "key-length": 128



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             }
             ],
             "local": {
               "local-pad-entry-name": "local-1"
             },
             "remote": {
               "remote-pad-entry-name": "remote-1"
             },
             "ietf-i2nsf-ike:spd": {
             "spd-entry": [
               {
                 "name": "protect-policy-1",
                 "ipsec-policy-config": {
                   "traffic-selector": {
                     "local-prefix": "192.0.2.0/16",
                     "remote-prefix": "198.51.100.0/16"
                   },
                   "processing-info": {
                     "action": "protect",
                     "ipsec-sa-cfg": {
                       "ietf-ipsec-iptfs:traffic-flow-security": {
                         "congestion-control": "true",
                         "l2-fixed-rate": 1000000000,
                         "packet-size": {
                           "use-path-mtu-discovery": "true"
                         },
                         "max-aggregation-time": "0.1",
                         "window-size": "1",
                         "send-immediately": "false",
                         "lost-packet-timer-interval": "0.2"
                       }
                     }
                   }
                 }
               }
             ]
           }
         }
       ]
     }
   }

                Figure 3: Example IP-TFS JSON configuration








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A.4.  Example JSON Operational Data

   This example illustrates operational data for IP-TFS in the ike case.
   Note that since this augments the ipsec ike tree only minimal ike
   configuration to satisfy the schema has been populated.

   {
     "ietf-i2nsf-ike:ipsec-ike": {
       "ietf-i2nsf-ike:conn-entry": [
         {
           "name": "my-peer-connection",
           "ike-sa-encr-alg": [
           {
             "id": 1,
             "algorithm-type": 12,
             "key-length": 128
           }
           ],
           "local": {
             "local-pad-entry-name": "local-1"
           },
           "remote": {
             "remote-pad-entry-name": "remote-1"
           },
           "ietf-i2nsf-ike:child-sa-info": {
             "ietf-ipsec-iptfs:traffic-flow-security": {
               "congestion-control": "true",
               "l2-fixed-rate": 1000000000,
               "packet-size": {
                 "use-path-mtu-discovery": "true"
               },
               "max-aggregation-time": "0.1",
               "window-size": "5",
               "send-immediately": "false",
               "lost-packet-timer-interval": "0.2"
             }
           }
         }
       ]
     }
   }

               Figure 4: Example IP-TFS JSON Operational data








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A.5.  Example JSON Operational Statistics

   This example shows the json formated statistics for IP-TFS.  Note a
   unidirectional IP-TFS transmit side is illustrated, with arbitrary
   numbers for transmit.

   {
     "ietf-i2nsf-ikeless:ipsec-ikeless": {
       "sad": {
         "sad-entry": [
           {
             "name": "sad-1",
             "ipsec-sa-config": {
               "spi": 1,
               "traffic-selector": {
                 "local-prefix": "192.0.2.1/16",
                 "remote-prefix": "198.51.100.0/16"
               }
             },
             "ietf-ipsec-iptfs:traffic-flow-security": {
               "window-size": "5",
               "send-immediately": "false",
               "lost-packet-timer-interval": "0.2"
             },
             "ietf-ipsec-iptfs:ipsec-stats": {
               "tx-pkts": "300",
               "tx-octets": "80000",
               "tx-drop-pkts": "2",
               "rx-pkts": "0",
               "rx-octets": "0",
               "rx-drop-pkts": "0"
             },
             "ietf-ipsec-iptfs:iptfs-inner-pkt-stats": {
               "tx-pkts": "250",
               "tx-octets": "75000",
               "rx-pkts": "0",
               "rx-octets": "0",
               "rx-incomplete-pkts": "0"
             },
             "ietf-ipsec-iptfs:iptfs-outer-pkt-stats": {
               "tx-all-pad-pkts": "40",
               "tx-all-pad-octets": "40000",
               "tx-extra-pad-pkts": "200",
               "tx-extra-pad-octets": "30000",
               "rx-all-pad-pkts": "0",
               "rx-all-pad-octets": "0",
               "rx-extra-pad-pkts": "0",
               "rx-extra-pad-octets": "0",



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               "rx-errored-pkts": "0",
               "rx-missed-pkts": "0"
             },
             "ipsec-sa-state": {
               "sa-lifetime-current": {
                 "time": 80000,
                 "bytes": 4000606,
                 "packets": 1000,
                 "idle": 5
               }
             }
           }
         ]
       }
     }
   }

                  Figure 5: Example IP-TFS JSON Statistics

   <tfs:traffic-flow-security> <tfs:reorder-window-
   size>300</tfs:reorder-window-size>

Authors' Addresses

   Don Fedyk
   LabN Consulting, L.L.C.

   Email: dfedyk@labn.net


   Christian Hopps
   LabN Consulting, L.L.C.

   Email: chopps@chopps.org

















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