[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-sun-softwire-yang) 00 01 02 03

Softwire Working Group                                            Q. Sun
Internet-Draft                                                   H. Wang
Intended status: Standards Track                                  Y. Cui
Expires: May 17, 2018                                Tsinghua University
                                                               I. Farrer
                                                              S. Zechlin
                                                     Deutsche Telekom AG
                                                            M. Boucadair
                                                                  Orange
                                                                R. Asati
                                                     Cisco Systems, Inc.
                                                       November 13, 2017


       YANG Modules for IPv4-in-IPv6 Address plus Port Softwires
                      draft-ietf-softwire-yang-03

Abstract

   This document defines YANG modules for the configuration and
   operation of IPv4-in-IPv6 softwire Border Relays and Customer
   Premises Equipment.  The model covers the Lightweight 4over6, MAP-E,
   and MAP-T softwire mechanisms.

Requirements Language

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

Status of This Memo

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

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

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

   This Internet-Draft will expire on May 17, 2018.





Sun, et al.               Expires May 17, 2018                  [Page 1]


Internet-Draft        YANG Module for A+P Softwires        November 2017


Copyright Notice

   Copyright (c) 2017 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Overview of the Models  . . . . . . . . . . . . . . . . . . .   3
     2.1.  Additional Configuration  . . . . . . . . . . . . . . . .   4
   3.  Softwire YANG CE Tree Diagram . . . . . . . . . . . . . . . .   5
     3.1.  Softwire CE Tree Diagram Descriptions . . . . . . . . . .   7
   4.  Softwire BR YANG Tree Diagram . . . . . . . . . . . . . . . .   8
     4.1.  BR Tree Diagrams  . . . . . . . . . . . . . . . . . . . .   8
     4.2.  Softwire BR Tree Diagram Descriptions . . . . . . . . . .  11
   5.  Softwire CE YANG Module . . . . . . . . . . . . . . . . . . .  12
   6.  BR Softwire YANG Module . . . . . . . . . . . . . . . . . . .  16
   7.  Common Softwire Element Groups YANG Module  . . . . . . . . .  24
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  31
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  31
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  32
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  32
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  32
     11.2.  Informative References . . . . . . . . . . . . . . . . .  33
   Appendix A.  Configuration Examples . . . . . . . . . . . . . . .  34
     A.1.  Configuration Example for a lw4o6 BR Binding-Table  . . .  34
     A.2.  Configuration Example for a MAP-E BR  . . . . . . . . . .  35
     A.3.  lw4o6 CE Configuration Example  . . . . . . . . . . . . .  37
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  40

1.  Introduction

   The IETF Softwire Working Group has developed several IPv4-in-IPv6
   softwire mechanisms to address various deployment contexts and
   constraints.  As a companion to the architectural specification
   documents, this document focuses on the provisioning of A+P softwire
   functional elements: Border Routers (BRs) and Customer Premises



Sun, et al.               Expires May 17, 2018                  [Page 2]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   Equipment (CEs).  The softwire mechanisims covered in this document
   are Lightweight 4 over 6 [RFC7596], MAP-E [RFC7597], and MAP-T
   [RFC7599].

   This document defines YANG data models [RFC6020] that can be used to
   configure and manage A+P softwire elements using the NETCONF protocol
   [RFC6241] for:

                         Configuration

                         Operational State

                         Notifications

1.1.  Terminology

   The reader should be familiar with the concepts and terms defined in
   [RFC7596], [RFC7597], [RFC7599], and the YANG data modelling language
   defined in [RFC6020] and [RFC7950].

   The meaning of the symbols in tree diagrams is defined in
   [I-D.ietf-netmod-yang-tree-diagrams].

2.  Overview of the Models

   The document defines these two YANG data modules for the
   configuration and monitoring of softwire functional elements:

   ietf-softwire-ce      Provides configuration and monititoring for
                         softwire CE element.

   ietf-softwire-br      Provides configuration and monititoring for
                         softwire BR element.

   In addition, the following module is also defined:

   ietf-softwire-common  Contains groups of functions that are common
                         and are imported into the CE and BR modules.

   This approach has been taken so that the various modules can be
   easily extended to support additional softwire mechanisms, if
   required.

   The modules are defined as augments to the interface YANG module
   [RFC7223].

   Within the BR and CE modules, the YANG "feature" statement is used to
   distinguish which of the different softwire mechanism(s) is relevant



Sun, et al.               Expires May 17, 2018                  [Page 3]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   for a specific element's configuraiton.  For each module, a choice
   statement is included for either 'binding' or 'algorithmic'.  Binding
   is used for configuring Lightweight 4over6, whereas Algorithmic is
   used for configuring MAP-T or MAP-E.

   In the 'algo-instances' container, a choice statement is included to
   specify MAP-E (encapsulation) or MAP-T (translation).  The following
   table shows the how these choices are used to indicate the desired
   softwire mechanism:

            +--------------------+-----------+---------------+
            |   S46 Mechanism    |  ce-type? |  data-plane?  |
            +--------------------+-----------+---------------+
            | Lightweight 4over6 |  binding  |      n/a      |
            |       MAP-E        | algorithm | encapsulation |
            |       MAP-T        | algorithm |  translation  |
            +--------------------+-----------+---------------+

         Table 1: Softwire Mechanism Choice Statement Enumeration

   NETCONF notifications also included.

      Note: Earlier versions of this document combined the softwire
      mechanisms by their associated technologies rather than their
      function in the architecture.  As the document was revised, it
      became apparent that dividing the modules by by their role in the
      architecture (CE or BR) was a better approach as this follows the
      intended function and existing implmemention approaches more
      closely.

2.1.  Additional Configuration

   The softwire module only aims to provide configuration relevant for
   softwires.  In order to fully specify a CE element, the following may
   also be necessary:

   o  IPv6 routing configuration, to enable CE to obtain one or more
      IPv6 prefixes for softwire usage.  YANG module for routing
      management is described in [RFC8022]

   o  IPv4 routing configuration, to add one or more IPv4 destination
      prefix(es) reachable via the configured softwire.  YANG module for
      routing management is described in [RFC8022]

   o  Stateful NAT44 / NAPT management, to optionally specify a port set
      (PSID) along with its length.  YANG module for NAT management is
      described in [I-D.ietf-opsawg-nat-yang] Note that




Sun, et al.               Expires May 17, 2018                  [Page 4]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   o  Stateless NAT46 management, required by softwire translation based
      mechanisms (i.e. the assignment of a Network-Specific prefix to
      use for IPv4/IPv6 translation).  YANG module for NAT management is
      described in [I-D.ietf-opsawg-nat-yang]

   As YANG modules for the configuration for these functions are already
   defined in other documents, they are not repeated, but imported here,
   as needed.  Appendix A.3 provides XML examples of how these models
   can be used together.

   The CE must already have minimal IPv6 configuration in place so it is
   reachable by the Netconf client to obtain softwire configuration.  If
   additional IPv6 specific configuration is necessary, the YANG modules
   defined in [RFC7277] and [RFC8022] may be used.

3.  Softwire YANG CE Tree Diagram

   Figure 1 describes the softwire YANG module for CE elements.  This
   module augments "ietf-interfaces", defined in [RFC7223] with an entry
   for the softwire.  This entry can be referenced to configure IPv4
   routing for the element.

   The module provides configuration and monitoring for all of the
   softwire mechanisms listed in Section 1.

     module: ietf-softwire-ce
       augment /if:interfaces/if:interface:
         +--rw softwire-payload-mtu?   uint16
         +--rw softwire-path-mru?      uint16
         +--rw (ce-type)?
            +--:(binding) {binding}?
            |  +--rw binding-ipv6info?       union
            |  +--rw br-ipv6-addr            inet:ipv6-address
            +--:(algorithm) {algorithm}?
               +--rw algo-instances
                  +--rw algo-instance* [id]
                     +--rw enable?             boolean
                     +--rw algo-versioning
                     |  +--rw version?   uint64
                     |  +--rw date?      yang:date-and-time
                     +--rw id                  uint32
                     +--rw name?               string
                     +--rw (data-plane)?
                     |  +--:(encapsulation)
                     |  |  +--rw br-ipv6-addr        inet:ipv6-address
                     |  +--:(translation)
                     |     +--rw dmr-ipv6-prefix?    inet:ipv6-prefix
                     +--rw ea-len              uint8



Sun, et al.               Expires May 17, 2018                  [Page 5]


Internet-Draft        YANG Module for A+P Softwires        November 2017


                     +--rw rule-ipv6-prefix    inet:ipv6-prefix
                     +--rw rule-ipv4-prefix    inet:ipv4-prefix
                     +--rw forwarding          boolean
       augment /if:interfaces-state/if:interface:
         +--ro ce-interface
            +--ro name?                               string
            +--ro type?                               identityref
            +--ro sent-ipv4-packets?
            |       yang:zero-based-counter64
            +--ro sent-ipv4-bytes?
            |       yang:zero-based-counter64
            +--ro sent-ipv6-packets?
            |       yang:zero-based-counter64
            +--ro sent-ipv6-bytes?
            |       yang:zero-based-counter64
            +--ro rcvd-ipv4-packets?
            |       yang:zero-based-counter64
            +--ro rcvd-ipv4-bytes?
            |       yang:zero-based-counter64
            +--ro rcvd-ipv6-packets?
            |       yang:zero-based-counter64
            +--ro rcvd-ipv6-bytes?
            |       yang:zero-based-counter64
            +--ro dropped-ipv4-packets?
            |       yang:zero-based-counter64
            +--ro dropped-ipv4-bytes?
            |       yang:zero-based-counter64
            +--ro dropped-ipv6-packets?
            |       yang:zero-based-counter64
            +--ro dropped-ipv6-bytes?
            |       yang:zero-based-counter64
            +--ro dropped-ipv4-fragments?
            |       yang:zero-based-counter64
            +--ro dropped-ipv4-fragment-bytes?
            |       yang:zero-based-counter64
            +--ro ipv6-fragments-reassembled?
            |       yang:zero-based-counter64
            +--ro ipv6-fragments-bytes-reassembled?
            |       yang:zero-based-counter64
            +--ro out-icmpv4-error-packets?
            |       yang:zero-based-counter64
            +--ro out-icmpv6-error-packets?
                    yang:zero-based-counter64

       notifications:
         +---n softwire-ce-event {binding}?
            +--ro ce-binding-ipv6-addr-change    inet:ipv6-address




Sun, et al.               Expires May 17, 2018                  [Page 6]


Internet-Draft        YANG Module for A+P Softwires        November 2017


                  Figure 1: Softwire YANG CE Tree Diagram

3.1.  Softwire CE Tree Diagram Descriptions

   Additional information on some of the important CE elements is
   provided below:

   o  softwire-payload-mtu: optionally used to set the IPv4 MTU for the
      softwire.  Needed if the softwire implementation is unable to
      correctly calculate the correct IPv4 size automatically.

   o  softwire-path-mru: optionally used to set the maximum IPv6
      softwire packet size that can be received, including the
      encapsulation/translation overhead.  Needed if the softwire
      implementation is unable to correctly calculate the correct IPv4
      size automatically.

   o  ce-type: provides a choice statement allowing the binding or
      algorithmic softwire mechanisms to be selected.

   Additional details relevant to binding softwire elements are:

   o  binding-ipv6info: used to set the IPv6 address type which is
      combined in a binding entry, for a complete address or a prefix.

   o  br-ipv6-addr: indicates the IPv6 of the remote BR.

   Additional details relevant to some of the important algorithmic
   elements are provided below:

   o  algo-versioning: optionally used to add a incremental version
      number and/or timestamp to the algorithm.  This can be used for
      logging/data retention purposes.  The version number is
      incremented and a new timestamp value written whenever a change is
      made to the algorithm or a new instance is created.

   o  forwarding: specifies whether the rule can be used as a Forward
      Mapping Rule (FMR).  If not set, this rule is a Basic Mapping Rule
      (BMR) only and must not be used for forwarding.  See Section 4.1
      of [RFC7598].

   o  ea-len: used to set the length of the Embedded-Address (EA), which
      defined in the mapping rule for a MAP domain.

   o  data-plane: provides a choice statement for either encapsulation
      (MAP-E) or translation (MAP-T).

   o  br-ipv6-addr: defines the IPv6 address of the BR for MAP-E.



Sun, et al.               Expires May 17, 2018                  [Page 7]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   o  dmr-ipv6-prefix: defines the Default Mapping Rule (DMR) IPv6
      prefix of the BR for MAP-T.

   o  stat-count (ro): use to show the numbers of packets and bytes
      information of specific element respectively.

   Additional information on the notification node is listed below:

   o  ce-binding-ipv6-addr-change: if the CE's binding-ipv6-address
      changes for any reason, it SHOULD notify the NETCONF client.

4.  Softwire BR YANG Tree Diagram

4.1.  BR Tree Diagrams

   Figure 2 describes the high level softwire YANG module for BRs.  The
   module provides configuration and monitoring for all of the softwire
   mechanisms listed in Section 1.

module: ietf-softwire-br
    +--rw br-instances
       +--rw (br-type)?
          +--:(binding) {binding}?
          |  +--rw binding {binding}?
          |     +--rw br-instance* [id]
          |        +--rw binding-table-versioning
          |        |  +--rw version?   uint64
          |        |  +--rw date?      yang:date-and-time
          |        +--rw id                          uint32
          |        +--rw name?                       string
          |        +--rw softwire-num-threshold      uint32
          |        +--rw softwires-payload-mtu       uint16
          |        +--rw softwire-path-mru           uint16
          |        +--rw enable-hairpinning?         boolean
          |        +--rw binding-table
          |        |  +--rw binding-entry* [binding-ipv6info]
          |        |     +--rw binding-ipv6info     union
          |        |     +--rw binding-ipv4-addr?   inet:ipv4-address
          |        |     +--rw port-set
          |        |     |  +--rw psid-offset?   uint8
          |        |     |  +--rw psid-len       uint8
          |        |     |  +--rw psid           uint16
          |        |     +--rw br-ipv6-addr?        inet:ipv6-address
          |        +--rw icmp-policy
          |        |  +--rw icmpv4-errors
          |        |  |  +--rw allow-incoming-icmpv4?    boolean
          |        |  |  +--rw generate-icmpv4-errors?   boolean
          |        |  +--rw icmpv6-errors



Sun, et al.               Expires May 17, 2018                  [Page 8]


Internet-Draft        YANG Module for A+P Softwires        November 2017


          |        |     +--rw generate-icmpv6-errors?   boolean
          |        |     +--rw icmpv6-errors-rate?       uint32
          |        +--ro traffic-stat
          |           +--ro sent-ipv4-packets?
          |           |       yang:zero-based-counter64
          |           +--ro sent-ipv4-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro sent-ipv6-packets?
          |           |       yang:zero-based-counter64
          |           +--ro sent-ipv6-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro rcvd-ipv4-packets?
          |           |       yang:zero-based-counter64
          |           +--ro rcvd-ipv4-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro rcvd-ipv6-packets?
          |           |       yang:zero-based-counter64
          |           +--ro rcvd-ipv6-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro dropped-ipv4-packets?
          |           |       yang:zero-based-counter64
          |           +--ro dropped-ipv4-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro dropped-ipv6-packets?
          |           |       yang:zero-based-counter64
          |           +--ro dropped-ipv6-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro dropped-ipv4-fragments?
          |           |       yang:zero-based-counter64
          |           +--ro dropped-ipv4-fragment-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro ipv6-fragments-reassembled?
          |           |       yang:zero-based-counter64
          |           +--ro ipv6-fragments-bytes-reassembled?
          |           |       yang:zero-based-counter64
          |           +--ro out-icmpv4-error-packets?
          |           |       yang:zero-based-counter64
          |           +--ro out-icmpv6-error-packets?
          |           |       yang:zero-based-counter64
          |           +--ro hairpin-ipv4-bytes?
          |           |       yang:zero-based-counter64
          |           +--ro hairpin-ipv4-packets?
          |           |       yang:zero-based-counter64
          |           +--ro active-softwire-num?                uint32
          +--:(algorithm) {algorithm}?
             +--rw algorithm {algorithm}?
                +--rw algo-instance* [id]
                   +--rw id                uint32



Sun, et al.               Expires May 17, 2018                  [Page 9]


Internet-Draft        YANG Module for A+P Softwires        November 2017


                   +--rw name?             string
                   +--rw algo-instances
                   |  +--rw algo-instance* [id]
                   |     +--rw enable?             boolean
                   |     +--rw algo-versioning
                   |     |  +--rw version?   uint64
                   |     |  +--rw date?      yang:date-and-time
                   |     +--rw id                  uint32
                   |     +--rw name?               string
                   |     +--rw (data-plane)?
                   |     |  +--:(encapsulation)
                   |     |  |  +--rw br-ipv6-addr
                   |     |  |          inet:ipv6-address
                   |     |  +--:(translation)
                   |     |     +--rw dmr-ipv6-prefix?   inet:ipv6-prefix
                   |     +--rw ea-len              uint8
                   |     +--rw rule-ipv6-prefix    inet:ipv6-prefix
                   |     +--rw rule-ipv4-prefix    inet:ipv4-prefix
                   |     +--rw forwarding          boolean
                   |     +--rw psid-offset?        uint8
                   |     +--rw psid-len            uint8
                   |     +--rw psid                uint16
                   +--ro traffic-stat
                      +--ro sent-ipv4-packets?
                      |       yang:zero-based-counter64
                      +--ro sent-ipv4-bytes?
                      |       yang:zero-based-counter64
                      +--ro sent-ipv6-packets?
                      |       yang:zero-based-counter64
                      +--ro sent-ipv6-bytes?
                      |       yang:zero-based-counter64
                      +--ro rcvd-ipv4-packets?
                      |       yang:zero-based-counter64
                      +--ro rcvd-ipv4-bytes?
                      |       yang:zero-based-counter64
                      +--ro rcvd-ipv6-packets?
                      |       yang:zero-based-counter64
                      +--ro rcvd-ipv6-bytes?
                      |       yang:zero-based-counter64
                      +--ro dropped-ipv4-packets?
                      |       yang:zero-based-counter64
                      +--ro dropped-ipv4-bytes?
                      |       yang:zero-based-counter64
                      +--ro dropped-ipv6-packets?
                      |       yang:zero-based-counter64
                      +--ro dropped-ipv6-bytes?
                      |       yang:zero-based-counter64
                      +--ro dropped-ipv4-fragments?



Sun, et al.               Expires May 17, 2018                 [Page 10]


Internet-Draft        YANG Module for A+P Softwires        November 2017


                      |       yang:zero-based-counter64
                      +--ro dropped-ipv4-fragment-bytes?
                      |       yang:zero-based-counter64
                      +--ro ipv6-fragments-reassembled?
                      |       yang:zero-based-counter64
                      +--ro ipv6-fragments-bytes-reassembled?
                      |       yang:zero-based-counter64
                      +--ro out-icmpv4-error-packets?
                      |       yang:zero-based-counter64
                      +--ro out-icmpv6-error-packets?
                              yang:zero-based-counter64

  notifications:
    +---n softwire-br-event {binding}?
    |  +--ro br-id?            -> /br-instances/binding/br-instance/id
    |  +--ro invalid-entry*    leafref
    |  +--ro added-entry*      inet:ipv6-address
    |  +--ro modified-entry*   leafref
    +---n softwire-algorithm-instance-event {algorithm}?
       +--ro algo-id
       |       -> /br-instances/algorithm/algo-instance/id
       +--ro invalid-entry-id*
       |       -> /br-instances/algorithm/algo-instance/id
       +--ro added-entry*
       |       -> /br-instances/algorithm/algo-instance/id
       +--ro modified-entry*
               -> /br-instances/algorithm/algo-instance/id

                      Figure 2: Softwire YANG BR Tree

4.2.  Softwire BR Tree Diagram Descriptions

   The descriptions for some of the leaves in the BR module are the same
   as in Figure 1.  Information on the additional elements are provided
   below:

   o  binding-table-versioning: optionally used to add an incremental
      version number and/or timestamp to the binding table.  This can be
      used for logging/data retention purposes.  The version number is
      incremented and a new timestamp value written whenever a change is
      made to the contents of the binding table or a new binding table
      list is created.

   o  binding-entry: used to define the binding relationship between
      3-tuples, which contains the lwB4's IPv6 address/prefix, the
      allocated IPv4 address and restricted port-set.  For detail
      information, please refer to [RFC7596].




Sun, et al.               Expires May 17, 2018                 [Page 11]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   o  softwire-num-threshold: used to set the maximum number of
      softwires that can be created on the lw4o6 element simultaneously.

   o  active-softwire-num (ro): used to present the number of softwires
      currently provisioned on the element.

   o  active (ro): used to show the status of particular binding-entry.

   Additional information on some of the important notification nodes is
   listed below:

   o  invalid-entry, added-entry, modified-entry: used to notify the
      client that a specific binding entry or MAP rule is expired or
      invalidated, added, or modified.

5.  Softwire CE YANG Module

   This module imports typedefs from [RFC6991].

<CODE BEGINS>file "ietf-softwire-ce@2017-11-14.yang"

module ietf-softwire-ce {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-softwire-ce";
  prefix "softwire-ce";

  import ietf-inet-types {prefix inet; }
  import ietf-interfaces {prefix if; }
  import iana-if-type {prefix ianaift; }
  import ietf-softwire-common {prefix softwire-common; }

  organization "Softwire Working Group";

  contact
    "
    Qi Sun <sunqi.ietf@gmail.com>
    Hao Wang <wangh13@mails.tsinghua.edu.cn>
    Yong Cui <yong@csnet1.cs.tsinghua.edu.cn>
    Ian <Farrer ian.farrer@telekom.de>
    Sladjana Zoric <sladjana.zoric@telekom.de>
    Mohamed Boucadair <mohamed.boucadair@orange.com>
    Rajiv <Asati rajiva@cisco.com>
    ";

  description
    "This document defines a YANG data module for the configuration and
    management of A+P Softwire Customer Premises Equipment (CEs). It
    covers Lightweight 4over6, MAP-E, and MAP-T mechanisms.



Sun, et al.               Expires May 17, 2018                 [Page 12]


Internet-Draft        YANG Module for A+P Softwires        November 2017


    Copyright (c) 2017 IETF Trust and the persons identified
    as authors of the code. All rights reserved.
    This version of this YANG module is part of RFC XXX; see the RFC
    itself for full legal notices.";

  revision 2017-11-14 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: YANG Modules for IPv4-in-IPv6 Address plus Port
      Softwires";
  }

  /*
   * Features
   */

  feature binding {
    description
      "Binding is used for configuring Lightweight 4over6 mechanism.

      Binding softwire mechanisms are IPv4-over-IPv6 tunnelling
      transition mechanisms specifically for complete independence
      between IPv6 subnet prefix (and /128 IPv6 address) and IPv4
      address with or without IPv4 address sharing.

      This is accomplished by maintaining state for each softwire
      (per-subscriber state) in the central Border Relay (BR) and a
      hub-and-spoke forwarding architecture. In order to delegate the
      NAPT function and achieve IPv4 address sharing, port-restricted
      IPv4 addresses needs to be allocated to CEs.";

    reference
      "RFC7596, RFC7597 & RFC7599";
  }

  feature algorithm {
    description
      "MAP-E is an IPv6 transition mechanism for transporting IPv4
      packets across an IPv6 network using IP encapsulation. MAP-E
      allows for a reduction of the amount of centralized state using
      rules to express IPv4/IPv6 address mappings. This introduces an
      algorithmic relationship between the IPv6 subnet and IPv4 address.

      MAP-T is an IPv6 transition mechanism for transporting IPv4
      packets across an IPv6 network using IP translation. It leverages
      a double stateless NAT64 based solution as well as the stateless
      algorithmic address & transport layer port mapping algorithm



Sun, et al.               Expires May 17, 2018                 [Page 13]


Internet-Draft        YANG Module for A+P Softwires        November 2017


      defined for MAP-E.

      This feature indicates the instance functions as a MAP-E or
      MAP-T instance.";

    reference
      "RFC7597 & RFC7599";
  }

  // Binding Entry
  grouping binding-entry {
    description
      "The lwAFTR maintains an address binding table that contains
      the binding between the lwB4's IPv6 address, the allocated IPv4
      address and restricted port-set.";

    leaf binding-ipv6info {

      type union {
        type inet:ipv6-address;
        type inet:ipv6-prefix;
      }

      description
        "The IPv6 information for a binding entry.
        If this is type IPv6 prefix, it indicates that
        the IPv6 source address of the CE is constructed
        according to the description in RFC7596;
        if it is type IPv6 address, it means the CE uses
        any valid /128 address from a prefix assigned to
        the CE.";
      reference
        "RFC7596";
    }

    leaf br-ipv6-addr {
      type inet:ipv6-address;
      mandatory true;
      description
        "The IPv6 address for lwaftr.";
    }
  }

  // configuration parameters for CE softwire interface
  augment "/if:interfaces/if:interface" {
    when "if:type = 'ianaift:tunnel'";
    description "CE Softwire interface configuration";




Sun, et al.               Expires May 17, 2018                 [Page 14]


Internet-Draft        YANG Module for A+P Softwires        November 2017


    leaf softwire-payload-mtu {
      type uint16;
      units bytes;
      description
        "The payload MTU for the Softwire tunnel.";
    }

    leaf softwire-path-mru {
      type uint16;
      units bytes;
      description
        "The path MRU for the softwire (payload + encapsulation
        overhead).";
    }

    choice ce-type {
      description "Sets the CE softwire mechanism";

      case binding {
        if-feature binding;
        description "CE binding configuration";
        uses binding-entry;
      }

      case algorithm {
        if-feature algorithm;
        description "CE algorithm configuration";
        uses softwire-common:algorithm;
      }
    }
  }

  // operational state parameters for CE softwire binding interface
  augment "/if:interfaces-state/if:interface" {
    when "if:type = 'ianaift:tunnel'";
    description "CE Softwire binding interface operational state";

    container ce-interface {
      config false;
      description
        "Data nodes for the operational state of interfaces.";

      leaf name {
        type string;
        description
          "The name of the interface.";
        reference
          "RFC 2863: The Interfaces Group MIB - ifName";



Sun, et al.               Expires May 17, 2018                 [Page 15]


Internet-Draft        YANG Module for A+P Softwires        November 2017


      }

      leaf type {
        type identityref {
          base if:interface-type;
        }
        description
          "The type of the interface.";
        reference
          "RFC 2863: The Interfaces Group MIB - ifType";
      }
      uses softwire-common:traffic-stat;
    }
  }

  /*
   * Notifications
   */

  notification softwire-ce-event {
    if-feature binding;
    description "CE notification";
    leaf ce-binding-ipv6-addr-change {
      type inet:ipv6-address;
      mandatory true;
      description
        "If the CE's binding-ipv6-address changes for any reason,
        it SHOULD notify the NETCONF client.";
    }
  }
}
<CODE ENDS>

6.  BR Softwire YANG Module

   This module imports typedefs from [RFC6991].

<CODE BEGINS>file "ietf-softwire-br@2017-11-14.yang"

module ietf-softwire-br {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-softwire-br";
  prefix "softwire-br";

  import ietf-inet-types {prefix inet; }
  import ietf-yang-types {prefix yang; }
  import ietf-softwire-common {prefix softwire-common; }




Sun, et al.               Expires May 17, 2018                 [Page 16]


Internet-Draft        YANG Module for A+P Softwires        November 2017


  organization "Softwire Working Group";

  contact
    "
    Qi Sun <sunqi.ietf@gmail.com>
    Hao Wang <wangh13@mails.tsinghua.edu.cn>
    Yong Cui <yong@csnet1.cs.tsinghua.edu.cn>
    Ian <Farrer ian.farrer@telekom.de>
    Sladjana Zoric <sladjana.zoric@telekom.de>
    Mohamed Boucadair <mohamed.boucadair@orange.com>
    Rajiv <Asati rajiva@cisco.com>
    ";

  description
    "This document defines a YANG data module for the configuration and
    management of A+P Softwire Border Routers. It covers Lightweight
    4over6, MAP-E, and MAP-T mechanisms.

    Copyright (c) 2017 IETF Trust and the persons identified
    as authors of the code. All rights reserved.
    This version of this YANG module is part of RFC XXX; see the RFC
    itself for full legal notices.";

  revision 2017-11-14 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: YANG Modules for IPv4-in-IPv6 Address plus Port
      Softwires";
  }

  /*
   * Features
   */

  feature binding {
    description
      "Binding is used for configuring Lightweight 4over6 mechanism.

      Binding softwire mechanisms are IPv4-over-IPv6 tunnelling
      transition mechanisms specifically for complete independence
      between IPv6 subnet prefix (and /128 IPv6 address) and IPv4
      address with or without IPv4 address sharing.

      This is accomplished by maintaining state for each softwire
      (per-subscriber state) in the central Border Relay (BR) and a
      hub-and-spoke forwarding architecture. In order to delegate the
      NAPT function and achieve IPv4 address sharing, port-restricted



Sun, et al.               Expires May 17, 2018                 [Page 17]


Internet-Draft        YANG Module for A+P Softwires        November 2017


      IPv4 addresses needs to be allocated to CEs.";

    reference
      "RFC7596, RFC7597 & RFC7599";
  }

  feature algorithm {
    description
      "MAP-E is an IPv6 transition mechanism for transporting IPv4
      packets across an IPv6 network using IP encapsulation. MAP-E
      allows for a reduction of the amount of centralized state using
      rules to express IPv4/IPv6 address mappings. This introduces an
      algorithmic relationship between the IPv6 subnet and IPv4 address.

      MAP-T is an IPv6 transition mechanism for transporting IPv4
      packets across an IPv6 network using IP translation. It leverages
      double stateless NAT64 based solution as well as the stateless
      algorithmic address & transport layer port mapping algorithm
      defined for MAP-E.

      This feature indicates the instance functions as a MAP-E or
      MAP-T instance.";

    reference
      "RFC7597 & RFC7599";
  }

  container br-instances {
    description
      "BR Instances";

    choice br-type {
      description
        "Select binding or algorithmic BR functionality.";
      case binding {
        if-feature binding;
        container binding {
          if-feature binding;
          description
            "lw4over6 (binding table) configuration.";
          list br-instance {
            key "id";
            description
              "A set of lwAFTRs to be configured.";
            container binding-table-versioning {
              description "binding table's version";
              leaf version{
                type uint64;



Sun, et al.               Expires May 17, 2018                 [Page 18]


Internet-Draft        YANG Module for A+P Softwires        November 2017


                description "Incremental version number of the binding
                  table";
              }
              leaf date {
                type yang:date-and-time;
                description "Timestamp of the binding
                  table";
              }
            }
            leaf id {
              type uint32;
              mandatory true;
              description "An instance identifier.";
            }
            leaf name {
              type string;
              description "The name for the lwaftr.";
            }
            leaf softwire-num-threshold {
              type uint32;
              mandatory true;
              description
                "The maximum number of softwires that can be created on
                the lwAFTR.";
            }
            leaf softwires-payload-mtu {
              type uint16;
              units bytes;
              mandatory true;
              description
                "The payload MTU for Lightweight 4over6 softwire.";
            }
            leaf softwire-path-mru {
              type uint16;
              units bytes;
              mandatory true;
              description
                "The path MRU for Lightweight 4over6 softwire.";
            }
            leaf enable-hairpinning {
              type boolean;
              default true;
              description
                "Enables/disables support for locally forwarding
                (hairpinning) traffic between two CEs";
              reference
                "RFC7596 Section 6.2";
            }



Sun, et al.               Expires May 17, 2018                 [Page 19]


Internet-Draft        YANG Module for A+P Softwires        November 2017


            container binding-table {
              description "binding table";
              list binding-entry {
                key "binding-ipv6info";
                description "binding entry";
                uses softwire-common:binding-entry;
              }
            }
            container icmp-policy {
              description
                "The lwAFTR can be configured to process or drop
                incoming ICMP messages, and to generate outgoing ICMP
                error messages or not.";

              container icmpv4-errors {
                description
                  "ICMPv4 error processing configuration";
                leaf allow-incoming-icmpv4 {
                  type boolean;
                  default true;
                  description
                    "Whether to allow processing of incoming ICMPv4
                    packets.";
                  reference
                    "RFC7596";
                }

                leaf generate-icmpv4-errors {
                  type boolean;
                  default true;
                  description
                    "Whether to generate outgoing ICMP error messages on
                    receipt of an inbound IPv4 packet with no matching
                    binding table entry.";
                  reference
                    "RFC7596 Seciton 5.2";
                }
              }

              container icmpv6-errors {
                description
                  "ICMPv6 error processing configuration";
                leaf generate-icmpv6-errors {
                  type boolean;
                  default true;
                  description
                    "Whether to generate ICMPv6 errors messages if no
                    matching binding table entry is found.";



Sun, et al.               Expires May 17, 2018                 [Page 20]


Internet-Draft        YANG Module for A+P Softwires        November 2017


                  reference
                    "RFC7596 Section 6.2";
                }
                leaf icmpv6-errors-rate {
                  type uint32;
                  description
                    "Rate limit threshold in messages per-second
                    for sending ICMPv6 errors messages";
                  reference
                    "RFC7596 Section 9";
                }
              }
            }

            container traffic-stat {
              config false;
              description
                "Traffic statistics information for the BR.";
              uses softwire-common:traffic-stat;

              leaf hairpin-ipv4-bytes {
                type yang:zero-based-counter64;
                description "IPv4 packets locally routed between two CEs
                  (hairpinned).";
              }

              leaf hairpin-ipv4-packets {
                type yang:zero-based-counter64;
                description "IPv4 bytes locally routed between two CEs
                  (hairpinned).";
              }

              leaf active-softwire-num {
                type uint32;
                config false;
                description
                  "The number of currently active softwires on the
                  lw4over6 (binding) instance.";
              }
            }
          }
        }
      }
      case algorithm {
        if-feature algorithm;
        container algorithm {
          if-feature algorithm;
          description



Sun, et al.               Expires May 17, 2018                 [Page 21]


Internet-Draft        YANG Module for A+P Softwires        November 2017


            "Indicate the instances support the MAP-E and MAP-T
            function. The instances advertise the map-e/map-t feature
            through the capability exchange mechanism when a NETCONF
            session is established.";
          list algo-instance {
            key "id";
            description "Instances of algorithm";
            leaf id {
              type uint32;
              mandatory true;
              description "id";
            }
            leaf name {
              type string;
              description "The MAP instance name.";
            }
            uses softwire-common:algorithm {
              augment "algo-instances/algo-instance"{
                description "Augments the port-set group for the
                algorithm.";
                uses softwire-common:port-set;
            }
            }
            container traffic-stat {
              config false;
              description
                "Traffic statistics information for the BR.";
              uses softwire-common:traffic-stat;
            }
          }
        }
      }
    }
  }

  /*
   * Notifications
   */
  notification softwire-br-event {
    if-feature binding;
    description "Notifications for BR.";
    leaf br-id {
      type leafref {
        path
          "/br-instances/binding/"
          + "br-instance/id";
      }
      description "...";



Sun, et al.               Expires May 17, 2018                 [Page 22]


Internet-Draft        YANG Module for A+P Softwires        November 2017


    }
    leaf-list invalid-entry {
      type leafref {
        path
          "/br-instances/binding/"
          + "br-instance[id=current()/../br-id]/"
          + "binding-table/binding-entry/binding-ipv6info";
      }
      description
        "Notify the client that a specific binding entry has been
        expired/invalid. The binding-ipv6info identifies an entry.";
    }
    leaf-list added-entry {
      type inet:ipv6-address;
      description
        "Notify the client that a binding entry has been added.
        The ipv6 address of that entry is the index. The client
        get other information from the lwaftr about the entry
        indexed by that ipv6 address.
        ";
    }
    leaf-list modified-entry {
      type leafref {
        path
          "/br-instances/binding/"
          + "br-instance[id=current()/../br-id]/"
          + "binding-table/binding-entry/binding-ipv6info";
      }
      description "...";
    }
  }

  notification softwire-algorithm-instance-event {
    if-feature algorithm;
    description "Notifications for MAP-E or MAP-T.";
    leaf algo-id {
      type leafref {
        path
          "/br-instances/algorithm/algo-instance/id";
      }
      mandatory true;
      description "MAP-E or MAP-T event.";
    }
    leaf-list invalid-entry-id {
      type leafref {
        path
          "/br-instances/algorithm/algo-instance/id";
      }



Sun, et al.               Expires May 17, 2018                 [Page 23]


Internet-Draft        YANG Module for A+P Softwires        November 2017


      description "Invalid entry event.";
    }
    leaf-list added-entry {
      type leafref {
        path
          "/br-instances/algorithm/algo-instance/id";
      }
      description "Added entry.";
    }
    leaf-list modified-entry {
      type leafref {
        path
          "/br-instances/algorithm/algo-instance/id";
      }
      description "Modified entry.";
    }
  }
}
<CODE ENDS>

7.  Common Softwire Element Groups YANG Module

   The following YANG module contains definitions that are used by both
   the softwire CE and softwire BR YANG modules.

<CODE BEGINS>file "ietf-softwire-common@2017-11-14.yang"

module ietf-softwire-common {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-softwire-common";
  prefix "softwire-common";

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

  organization "Softwire Working Group";

  contact
    "
    Qi Sun <sunqi.ietf@gmail.com>
    Hao Wang <wangh13@mails.tsinghua.edu.cn>
    Yong Cui <yong@csnet1.cs.tsinghua.edu.cn>
    Ian <Farrer ian.farrer@telekom.de>
    Sladjana Zoric <sladjana.zoric@telekom.de>
    Mohamed Boucadair <mohamed.boucadair@orange.com>
    Rajiv <Asati rajiva@cisco.com>
    ";




Sun, et al.               Expires May 17, 2018                 [Page 24]


Internet-Draft        YANG Module for A+P Softwires        November 2017


  description
    "This document defines a YANG data model for the configuration and
    management of A+P Softwire Customer Premises Equipment (CEs). It
    covers Lightweight 4over6, MAP-E and MAP-T mechanisms.

    Copyright (c) 2017 IETF Trust and the persons identified
    as authors of the code. All rights reserved.
    This version of this YANG module is part of RFC XXX; see the RFC
    itself for full legal notices.";

  revision 2017-11-14 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: YANG Modules for IPv4-in-IPv6 Address plus Port
      Softwires";
  }

  /*
   * Grouping
   */

  grouping port-set {
    description
      "Indicates a set of ports.

      It may be a simple port range, or use the PSID algorithm
      to represent a range of transport layer ports which will
      be used by a NAPT.";

    leaf psid-offset {
      type uint8 {
        range 0..16;
      }
      description
        "The number of offset bits. In Lightweight 4over6,
        the default value is 0 for assigning one contiguous
        port range. In MAP-E/T, the default value is 6,
        which means the system ports (0-1023) are excluded by
        default and assigns port ranges distributed across the
        entire port space, depending on either psid-len or the
        number of contiguous ports.";
    }

    leaf psid-len {
      type uint8 {
        range 0..15;
      }



Sun, et al.               Expires May 17, 2018                 [Page 25]


Internet-Draft        YANG Module for A+P Softwires        November 2017


      mandatory true;
      description
        "The length of PSID, representing the sharing
        ratio for an IPv4 address. This, along with ea-len, also
        helps to calculate the number of contiguous ports per
        port range";
    }

    leaf psid {
      type uint16;
      mandatory true;
      description
        "Port Set Identifier (PSID) value, which
        identifies a set of ports algorithmically.";
    }
  }

  grouping binding-entry {
    description
      "The lwAFTR maintains an address binding table that contains
      the binding between the lwB4's IPv6 address, the allocated IPv4
      address and restricted port-set.";
    leaf binding-ipv6info {
      type union {
        type inet:ipv6-address;
        type inet:ipv6-prefix;
      }
      description
        "The IPv6 information for a binding entry.
        If this is an IPv6 prefix, it indicates that
        the IPv6 source address of the CE is constructed
        according to the description in RFC7596;
        if it is an IPv6 address, it means the CE uses
        any /128 address from the assigned CE prefix.";
      reference
        "RFC7596";
    }
    leaf binding-ipv4-addr {
      type inet:ipv4-address;
      description
        "The IPv4 address assigned to the lwB4, which is
        used as the IPv4 external address
        for lwB4 local NAPT44.";
    }
    container port-set {
      description
        "For Lightweight 4over6, the default value
        of offset should be 0, to configure one contiguous



Sun, et al.               Expires May 17, 2018                 [Page 26]


Internet-Draft        YANG Module for A+P Softwires        November 2017


        port range.";
      uses port-set {
        refine "psid-offset" {
          default "0";
        }
      }
    }
    leaf br-ipv6-addr {
      type inet:ipv6-address;
      description
        "The IPv6 address for lwaftr.";
    }
  }

  grouping algorithm {
    description
      "Indicate the instances support the MAP-E and MAP-T function.
      The instances advertise the map-e feature through the
      capability exchange mechanism when a NETCONF session is
      established.";
    container algo-instances {
      description
        "A set of MAP-E or MAP-T instances to be configured,
        applying to BRs and CEs. A MAP-E/T instance defines a MAP
          domain comprising one or more MAP-CE and MAP-BR";
      list algo-instance {
        key "id";
        description "MAP forwarding rule instance for MAP-E/MAP-T";
        leaf enable {
          type boolean;
          description
            "Enable/disable individual MAP-E or MAP-T rule.";
        }
        container algo-versioning {
          description "algorithm's version";
          leaf version {
            type uint64;
            description "Incremental version number for the algorithm";
          }
          leaf date {
            type yang:date-and-time;
            description "Timestamp to the algorithm";
          }
        }
        leaf id {
          type uint32;
          mandatory true;
          description "Algorithm Instance ID";



Sun, et al.               Expires May 17, 2018                 [Page 27]


Internet-Draft        YANG Module for A+P Softwires        November 2017


        }
        leaf name {
          type string;
          description "The name for the instance.";
        }
        choice data-plane {
          description "Selects MAP-E (encapsulation) or MAP-T
          (translation)";
          case encapsulation {
            description "encapsulation for MAP-E";
            leaf br-ipv6-addr {
              type inet:ipv6-address;
              mandatory true;
              description
                "The IPv6 address of the MAP-E BR.";
            }
          }
          case translation {
            description "translation for MAP-T";
            leaf dmr-ipv6-prefix {
              type inet:ipv6-prefix;
              description
                "The IPv6 prefix of the MAP-T BR. ";
            }
          }
        }
        leaf ea-len {
          type uint8;
          mandatory true;
          description
            "Embedded Address (EA) bits are the IPv4 EA-bits in the IPv6
            address identify an IPv4 prefix/address (or part thereof) or
            a shared IPv4 address (or part thereof) and a port-set
            identifier. The length of the EA-bits is defined as part of
            a MAP rule for a MAP domain.";
        }
        leaf rule-ipv6-prefix {
          type inet:ipv6-prefix;
          mandatory true;
          description
            "The Rule IPv6 prefix defined in the mapping rule.";
        }
        leaf rule-ipv4-prefix {
          type inet:ipv4-prefix;
          mandatory true;
          description
            "The Rule IPv4 prefix defined in the mapping rule.";
        }



Sun, et al.               Expires May 17, 2018                 [Page 28]


Internet-Draft        YANG Module for A+P Softwires        November 2017


        leaf forwarding {
          type boolean;
          mandatory true;
          description
            "This parameter specifies whether the rule may be used for
            forwarding (FMR). If set, this rule is used as an FMR;
          if not set, this rule is a BMR only and must not be used
            for forwarding.";
        }
      }
    }
  }

  grouping traffic-stat {
    description "Traffic statistics";
    leaf sent-ipv4-packets {
      type yang:zero-based-counter64;
      description "Number of decapsulated/translated IPv4 packets sent.
      ";
    }
    leaf sent-ipv4-bytes {
      type yang:zero-based-counter64;
      description "Decapsulated/translated IPv4 traffic sent, in bytes";
    }
    leaf sent-ipv6-packets {
      type yang:zero-based-counter64;
      description "Number of encapsulated/translated IPv6 packets sent.
      ";
    }
    leaf sent-ipv6-bytes {
      type yang:zero-based-counter64;
      description "Encapsulated/translated IPv6 traffic sent, in bytes";
    }
    leaf rcvd-ipv4-packets {
      type yang:zero-based-counter64;
      description "Number of IPv4 packets received for processing.";
    }
    leaf rcvd-ipv4-bytes {
      type yang:zero-based-counter64;
      description "IPv4 traffic received for processing, in bytes";
    }
    leaf rcvd-ipv6-packets {
      type yang:zero-based-counter64;
      description "Number of IPv6 packets received for processing.";
    }
    leaf rcvd-ipv6-bytes {
      type yang:zero-based-counter64;
      description "IPv6 traffic received for processing, in bytes";



Sun, et al.               Expires May 17, 2018                 [Page 29]


Internet-Draft        YANG Module for A+P Softwires        November 2017


    }
    leaf dropped-ipv4-packets {
      type yang:zero-based-counter64;
      description "Number of IPv4 packets dropped.";
    }
    leaf dropped-ipv4-bytes {
      type yang:zero-based-counter64;
      description "IPv4traffic dropped, in bytes";
    }
    leaf dropped-ipv6-packets {
      type yang:zero-based-counter64;
      description "Number of IPv4 packets dropped.";
    }
    leaf dropped-ipv6-bytes {
      type yang:zero-based-counter64;
      description "IPv4 traffic dropped, in bytes";
    }
    leaf dropped-ipv4-fragments {
      type yang:zero-based-counter64;
      description "Number of fragmented IPv4 packets dropped";
    }
    leaf dropped-ipv4-fragment-bytes {
      type yang:zero-based-counter64;
      description "Fragmented IPv4 traffic dropped, in bytes";
    }
    leaf ipv6-fragments-reassembled {
      type yang:zero-based-counter64;
      description "Number of IPv6 fragments successfully reassembled";
    }
    leaf ipv6-fragments-bytes-reassembled {
      type yang:zero-based-counter64;
      description "IPv6 fragments successfully reassembled, in bytes";
    }
    leaf out-icmpv4-error-packets {
      type yang:zero-based-counter64;
      description "Internally generated ICMPv4 error packets.";
    }
    leaf out-icmpv6-error-packets {
      type yang:zero-based-counter64;
      description "Internally generted ICMPv6 error packets.";
    }
  }
}
<CODE ENDS>







Sun, et al.               Expires May 17, 2018                 [Page 30]


Internet-Draft        YANG Module for A+P Softwires        November 2017


8.  Security Considerations

   The YANG module defined in this document 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 [RFC5246].

   The NETCONF access control model [RFC6536] 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.

   All data nodes defined in the YANG modules which can be created,
   modified, and deleted (i.e., config true, which is the default) are
   considered sensitive.  Write operations (e.g., edit-config) applied
   to these data nodes without proper protection can negatively affect
   network operations.

9.  IANA Considerations

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

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

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

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

   This document requests that IANA registers the following YANG modules
   in the "YANG Module Names" registry [RFC6020].

               name: ietf-softwire-ce
               namespace: urn:ietf:params:xml:ns:yang:softwire-ce
               prefix: softwire-ce
               reference: RFC XXXX







Sun, et al.               Expires May 17, 2018                 [Page 31]


Internet-Draft        YANG Module for A+P Softwires        November 2017


               name: ietf-softwire-br
               namespace: urn:ietf:params:xml:ns:yang:softwire-br
               prefix: softwire-br
               reference: RFC XXXX

               name: ietf-softwire-common
               namespace: urn:ietf:params:xml:ns:yang:softwire-common
               prefix: softwire-br
               reference: RFC XXXX

10.  Acknowledgements

   The authors would like to thank Lishan Li, Bert Wijnen, Giles Heron,
   Ole Troan, and Leo Tietz for their contributions to this work.

11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

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

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [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>.

   [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>.





Sun, et al.               Expires May 17, 2018                 [Page 32]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              DOI 10.17487/RFC6536, March 2012,
              <https://www.rfc-editor.org/info/rfc6536>.

   [RFC7223]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 7223, DOI 10.17487/RFC7223, May 2014,
              <https://www.rfc-editor.org/info/rfc7223>.

   [RFC7596]  Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
              Farrer, "Lightweight 4over6: An Extension to the Dual-
              Stack Lite Architecture", RFC 7596, DOI 10.17487/RFC7596,
              July 2015, <https://www.rfc-editor.org/info/rfc7596>.

   [RFC7597]  Troan, O., Ed., Dec, W., Li, X., Bao, C., Matsushima, S.,
              Murakami, T., and T. Taylor, Ed., "Mapping of Address and
              Port with Encapsulation (MAP-E)", RFC 7597,
              DOI 10.17487/RFC7597, July 2015,
              <https://www.rfc-editor.org/info/rfc7597>.

   [RFC7598]  Mrugalski, T., Troan, O., Farrer, I., Perreault, S., Dec,
              W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for
              Configuration of Softwire Address and Port-Mapped
              Clients", RFC 7598, DOI 10.17487/RFC7598, July 2015,
              <https://www.rfc-editor.org/info/rfc7598>.

   [RFC7599]  Li, X., Bao, C., Dec, W., Ed., Troan, O., Matsushima, S.,
              and T. Murakami, "Mapping of Address and Port using
              Translation (MAP-T)", RFC 7599, DOI 10.17487/RFC7599, July
              2015, <https://www.rfc-editor.org/info/rfc7599>.

   [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>.

   [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>.

11.2.  Informative References

   [I-D.ietf-netmod-yang-tree-diagrams]
              Bjorklund, M. and L. Berger, "YANG Tree Diagrams", draft-
              ietf-netmod-yang-tree-diagrams-02 (work in progress),
              October 2017.






Sun, et al.               Expires May 17, 2018                 [Page 33]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   [I-D.ietf-opsawg-nat-yang]
              Boucadair, M., Sivakumar, S., Jacquenet, C., Vinapamula,
              S., and Q. Wu, "A YANG Data Model for Network Address
              Translation (NAT) and Network Prefix Translation (NPT)",
              draft-ietf-opsawg-nat-yang-08 (work in progress), November
              2017.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7277]  Bjorklund, M., "A YANG Data Model for IP Management",
              RFC 7277, DOI 10.17487/RFC7277, June 2014,
              <https://www.rfc-editor.org/info/rfc7277>.

   [RFC8022]  Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
              Management", RFC 8022, DOI 10.17487/RFC8022, November
              2016, <https://www.rfc-editor.org/info/rfc8022>.

Appendix A.  Configuration Examples

   The following sections of the document provide examples on how these
   YANG modules could be used for configuring softwire elements.

A.1.  Configuration Example for a lw4o6 BR Binding-Table

   The lwAFTR maintains an address binding table which contains the
   following 3-tuples:

   o  IPv6 Address for a single lwB4

   o  Public IPv4 Address

   o  Restricted port-set

   The entry has two functions: the IPv6 encapsulation of inbound IPv4
   packets destined to the lwB4 and the validation of outbound IPv4-in-
   IPv6 packets received from the lwB4 for de-capsulation.

   Consider an example for the following lw4o6 binding table entry:

   lwB4 Binding IPv6 Address:  2001:db8::1

   lwB4 Binding IPv4 Address:  192.0.2.1

   lwB4 IPv6 Address:          123

   lwB4 PSID Length            8



Sun, et al.               Expires May 17, 2018                 [Page 34]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   BR IPv6 Address:            2001:db8:1::2


<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <softwire-config xmlns="urn:ietf:params:xml:ns:yang:ietf-softwire-br">
    <br-instances>
      <binding>
          <br-instance>
            <id>1</id>
            <binding-table>
              <binding-entry>
                <binding-ipv6info>2001:db8::1</binding-ipv6info>
                <binding-ipv4-addr>192.0.2.1</binding-ipv4-addr>
                <port-set>
                  <psid>123</psid>
                  <psid-len>8</psid-len>
                </port-set>
                <br-ipv6-addr>2001:db8:1::2</br-ipv6-addr>
              </binding-entry>
            </binding-table>
            <softwire-num-threshold>1024</softwire-num-threshold>
            <softwire-path-mru>1540</softwire-path-mru>
            <softwire-payload-mtu>1500</softwire-payload-mtu>
          </br-instance>
      </binding>
    </br-instances>
  </softwire-config>
</config>


              Figure 3: lw4o6 Binding-Table Configuration XML

A.2.  Configuration Example for a MAP-E BR

   A MAP-E BR is configured with forward mapping rules for the clients
   it is serving.  In this example (taken from [RFC7597], Appendix A,
   Example 2), the following parameters are required:

   o  Rule IPv6 Prefix

   o  Rule IPv4 Prefix

   o  Rule EA-bit bit length

   o  IPv6 Address of MAP-BR

   The mapping rule has two functions: identifying the destination CE
   IPv6 address for encapsulating inbound IPv4 packets and the



Sun, et al.               Expires May 17, 2018                 [Page 35]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   validation of outbound IPv4-in-IPv6 packets received from the CE for
   de-capsulation.

   The transport type for the data plane also needs to be configured for
   encapsulation to enable MAP-E and forwarding needs to be enabled.

   Consider an example for the following MAP-E Forwarding Mapping Rule:

   Data plane:         encapsulation

   Rule IPv6 Prefix:   2001:db8::/40

   Rule IPv4 Prefix:   192.0.2.0/24

   Rule EA-bit Length: 16

   BR IPv6 Address:    2001:db8:ffff::1

   Here is the example MAP-E BR configuration xml:


<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <softwire-config xmlns="urn:ietf:params:xml:ns:yang:ietf-softwire-br">
    <br-instances>
      <algorithm>
          <algo-instance>
            <id>42</id>
            <algo-instances>
              <algo-instance>
                <id>1234</id>
                <data-plane>encapsulation</data-plane>
                <ea-len>16</ea-len>
                <rule-ipv4-prefix>192.0.2.0/24</rule-ipv4-prefix>
                <rule-ipv6-prefix>2001:db8::/40</rule-ipv6-prefix>
                <forwarding>true</forwarding>
                <br-ipv6-addr>2001:db8:ffff::1</br-ipv6-addr>
                <psid-offset>6</psid-offset>
                <psid-len>8</psid-len>
              </algo-instance>
            </algo-instances>
          </algo-instance>
      </algorithm>
    </br-instances>
  </softwire-config>
</config>


                   Figure 4: MAP-E FMR Configuration XML



Sun, et al.               Expires May 17, 2018                 [Page 36]


Internet-Draft        YANG Module for A+P Softwires        November 2017


A.3.  lw4o6 CE Configuration Example

   The following section provides XML examples for configuring a lw4o6
   CE.  Examples for routing and NAT44 are also provided for
   convienience.

   Consider an example for the following lw4o6 CE Configuration:

   lwB4 Binding IPv6 Address:  2001:db8::1

   lwB4 Binding IPv4 Address:  192.0.2.1

   lwB4 IPv6 Address:          123

   lwB4 PSID Length            8

   BR IPv6 Address:            2001:db8:1::2

   <config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
       <interface>
         <name>lw4o6-wan</name>
         <type
           xmlns:iana="urn:ietf:params:xml:ns:yang:iana-if-type">
           iana:tunnel
         </type>
         <ce-interface
           xmlns="urn:ietf:params:xml:ns:yang:ietf-softwire-ce">
           <br-ipv6-addr>2001:db8:1::2</br-ipv6-addr>
           <binding-ipv6info>2001:db8::1</binding-ipv6info>
         </ce-interface>
       </interface>
     </interfaces>
   </config>

                   Figure 5: lw4o6 CE Configuration XML

   In the above example, the interface name is defined for the softwire
   tunnel.  This name is then referenced by the routing configuration
   for the IPv4 route.  The following section provides example
   configuration for the CE's IPv4 routing, using the YANG module
   described in [RFC8022].









Sun, et al.               Expires May 17, 2018                 [Page 37]


Internet-Draft        YANG Module for A+P Softwires        November 2017


<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
    <control-plane-protocols>
      <control-plane-protocol>
        <type>static</type>
        <name>v4</name>
        <static-routes>
          <ipv4
          xmlns="urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing">
            <route>
              <destination-prefix>0.0.0.0/0</destination-prefix>
              <next-hop>
                <outgoing-interface>lw4o6-wan</outgoing-interface>
              </next-hop>
            </route>
          </ipv4>
        </static-routes>
      </control-plane-protocol>
    </control-plane-protocols>
  </routing>
</config>

               Figure 6: lw4o6 CE Routing Configuration XML

   The following section provides example configuration for the CE's
   NAPT44 function, using the YANG module described in
   [I-D.ietf-opsawg-nat-yang].

 <config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
   <nat xmlns="urn:ietf:params:xml:ns:yang:ietf-nat">
    <instances>
      <instance>
        <id>1</id>
        <policy>
         <policy-id>1</policy-id>
         <external-ip-address-pool>
           <pool-id>1</pool-id>
           <external-ip-pool>192.0.2.1</external-ip-pool>
         </external-ip-address-pool>
         <port-set-restrict>
           <port-set-algo>
             <psid-offset>6</psid-offset>
             <psid-len>8</psid-len>
             <psid>52</psid>
           </port-set-algo>
         </port-set-restrict>
         <notify-pool-usage>
           <pool-id>1</pool-id>



Sun, et al.               Expires May 17, 2018                 [Page 38]


Internet-Draft        YANG Module for A+P Softwires        November 2017


           <high-threshold>80</high-threshold>
         </notify-pool-usage>
         </policy>
         <mapping-limits>
          <limit-per-protocol>
           <protocol-id>1</protocol-id>
           <limit>8</limit>
          </limit-per-protocol>
          <limit-per-protocol>
           <protocol-id>6</protocol-id>
           <limit>32</limit>
          </limit-per-protocol>
          <limit-per-protocol>
           <protocol-id>17</protocol-id>
           <limit>16</limit>
          </limit-per-protocol>
         </mapping-limits>
         <mapping-table>
           <mapping-entry>
             <index>1</index>
             <external-src-address>192.0.2.1/32</external-src-address>
             <internal-src-address>192.168.1.0/24</internal-src-address>
             <transport-protocol>6</transport-protocol>
           </mapping-entry>
           <mapping-entry>
             <index>2</index>
             <external-src-address>192.0.2.1/32</external-src-address>
             <internal-src-address>192.168.1.0/24</internal-src-address>
             <transport-protocol>17</transport-protocol>
           </mapping-entry>
           <mapping-entry>
             <index>3</index>
             <external-src-address>192.0.2.1/32</external-src-address>
             <internal-src-address>192.168.1.0/24</internal-src-address>
             <transport-protocol>1</transport-protocol>
           </mapping-entry>
         </mapping-table>
       </instance>
     </instances>
   </nat>
 </config>

                   Figure 7: lw4o6 NAT Configuration XML








Sun, et al.               Expires May 17, 2018                 [Page 39]


Internet-Draft        YANG Module for A+P Softwires        November 2017


Authors' Addresses

   Qi Sun
   Tsinghua University
   Beijing  100084
   P.R. China

   Phone: +86-10-6278-5822
   Email: sunqi.ietf@gmail.com


   Hao Wang
   Tsinghua University
   Beijing  100084
   P.R. China

   Phone: +86-10-6278-5822
   Email: wangh13@mails.tsinghua.edu.cn


   Yong Cui
   Tsinghua University
   Beijing  100084
   P.R. China

   Phone: +86-10-6260-3059
   Email: yong@csnet1.cs.tsinghua.edu.cn


   Ian Farrer
   Deutsche Telekom AG
   CTO-ATI,Landgrabenweg 151
   Bonn, NRW  53227
   Germany

   Email: ian.farrer@telekom.de


   Sladjana Zechlin
   Deutsche Telekom AG
   Landgrabenweg 151
   Bonn, NRW  53227
   Germany

   Email: sladjana.zechlin@telekom.de






Sun, et al.               Expires May 17, 2018                 [Page 40]


Internet-Draft        YANG Module for A+P Softwires        November 2017


   Mohamed Boucadair
   Orange
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com


   Rajiv Asati
   Cisco Systems, Inc.
   7025 Kit Creek Rd.
   RTP, NC  27709
   USA

   Email: Rajiva@cisco.com




































Sun, et al.               Expires May 17, 2018                 [Page 41]


Html markup produced by rfcmarkup 1.124, available from https://tools.ietf.org/tools/rfcmarkup/