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Babel Information Model
draft-ietf-babel-information-model-08

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 9046.
Authors Barbara Stark , Mahesh Jethanandani
Last updated 2019-08-04 (Latest revision 2019-07-21)
Replaces draft-stark-babel-information-model
RFC stream Internet Engineering Task Force (IETF)
Formats
Reviews
Additional resources Mailing list discussion
Stream WG state In WG Last Call
Document shepherd Donald E. Eastlake 3rd
IESG IESG state Became RFC 9046 (Informational)
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD (None)
Send notices to Donald Eastlake <d3e3e3@gmail.com>
draft-ietf-babel-information-model-08
Babel routing protocol                                          B. Stark
Internet-Draft                                                      AT&T
Intended status: Informational                           M. Jethanandani
Expires: February 4, 2020                                         VMware
                                                          August 3, 2019

                        Babel Information Model
                 draft-ietf-babel-information-model-08

Abstract

   This Babel Information Model can be used to create data models under
   various data modeling regimes.  It allows a Babel implementation (via
   a management protocol or interface) to report on its current state
   and may allow some limited configuration of protocol constants.

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 February 4, 2020.

Copyright Notice

   Copyright (c) 2019 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.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     1.2.  Notation  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  The Information Model . . . . . . . . . . . . . . . . . . . .   7
     3.1.  Definition of babel-information-obj . . . . . . . . . . .   7
     3.2.  Definition of babel-constants-obj . . . . . . . . . . . .   8
     3.3.  Definition of babel-interfaces-obj  . . . . . . . . . . .   9
     3.4.  Definition of babel-if-stats-obj  . . . . . . . . . . . .  11
     3.5.  Definition of babel-neighbors-obj . . . . . . . . . . . .  12
     3.6.  Definition of babel-nbr-stats-obj . . . . . . . . . . . .  13
     3.7.  Definition of babel-routes-obj  . . . . . . . . . . . . .  14
     3.8.  Definition of babel-hmac-key-sets-obj . . . . . . . . . .  15
     3.9.  Definition of babel-hmac-keys-obj . . . . . . . . . . . .  16
     3.10. Definition of babel-dtls-cert-sets-obj  . . . . . . . . .  17
     3.11. Definition of babel-dtls-certs-obj  . . . . . . . . . . .  17
   4.  Extending the Information Model . . . . . . . . . . . . . . .  18
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  19
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  20
   Appendix A.  Open Issues  . . . . . . . . . . . . . . . . . . . .  21
   Appendix B.  Change Log . . . . . . . . . . . . . . . . . . . . .  23
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  27

1.  Introduction

   Babel is a loop-avoiding distance-vector routing protocol defined in
   [I-D.ietf-babel-rfc6126bis].  [I-D.ietf-babel-hmac] defines a
   security mechanism that allows Babel packets to be cryptographically
   authenticated, and [I-D.ietf-babel-dtls] defines a security mechanism
   that allows Babel packets to be encrypted.  This document describes
   an information model for Babel (including implementations using one
   of these security mechanisms) that can be used to create management
   protocol data models (such as a NETCONF [RFC6241] YANG [RFC7950] data
   model).

   Due to the simplicity of the Babel protocol, most of the information
   model is focused on reporting Babel protocol operational state, and
   very little of that is considered mandatory to implement (contingent
   on a management protocol with Babel support being implemented).  Some
   parameters may be configurable.  However, it is up to the Babel
   implementation whether to allow any of these to be configured within
   its implementation.  Where the implementation does not allow

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   configuration of these parameters, it may still choose to expose them
   as read-only.

   The Information Model is presented using a hierarchical structure.
   This does not preclude a data model based on this Information Model
   from using a referential or other structure.

1.1.  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] and updated
   by [RFC8174].

1.2.  Notation

   This document uses a programming language-like notation to define the
   properties of the objects of the information model.  An optional
   property is enclosed by square brackets, [ ], and a list property is
   indicated by two numbers in angle brackets, <m..n>, where m indicates
   the minimal number of list elements, and n indicates the maximum
   number of list elements.  The symbol * for n means there are no
   defined limits on the number of list elements.  Each parameter and
   object includes an indication of "ro" or "rw". "ro" means the
   parameter or object is read-only. "rw" means it is read-write.  For
   an object, read-write means instances of the object can be created or
   deleted.  If an implementation is allowed to choose to implement a
   "rw" parameter as read-only, this is noted in the parameter
   description.

   The object definitions use base types that are defined as follows:

   binary      A binary string (sequence of octets).

   boolean     A type representing a Boolean value.

   counter     A non-negative integer that monotonically increases.
               Counters may have discontinuities and they are not
               expected to persist across restarts.

   datetime    A type representing a date and time using the Gregorian
               calendar.  The datetime format MUST conform to RFC 3339
               [RFC3339].

   ip-address  A type representing an IP address.  This type supports
               both IPv4 and IPv6 addresses.

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   operation   A type representing a remote procedure call or other
               action that can be used to manipulate data elements or
               system behaviors.

   reference   A type representing a reference to another information or
               data model element or to some other device resource.

   string      A type representing a human-readable string consisting of
               a (possibly restricted) subset of Unicode and ISO/IEC
               10646 [ISO.10646] characters.

   uint        A type representing an unsigned integer number.  This
               information model does not define a precision.

2.  Overview

   The Information Model is hierarchically structured as follows:

   +-- babel-information
      +-- babel-implementation-version
      +-- babel-enable
      +-- router-id
      +-- self-seqno
      +-- babel-metric-comp-algorithms
      +-- babel-security-supported
      +-- babel-hmac-algorithms
      +-- babel-dtls-cert-types
      +-- babel-stats-enable
      +-- babel-stats-reset
      +-- babel-constants
      |  +-- babel-udp-port
      |  +-- babel-mcast-group
      +-- babel-interfaces
      |  +-- babel-interface-reference
      |  +-- babel-interface-enable
      |  +-- babel-interface-metric-algorithm
      |  +-- babel-interface-split-horizon
      |  +-- babel-mcast-hello-seqno
      |  +-- babel-mcast-hello-interval
      |  +-- babel-update-interval
      |  +-- babel-hmac-enable
      |  +-- babel-if-hmac-key-sets
      |  +-- babel-hmac-algorithm
      |  +-- babel-hmac-verify
      |  +-- babel-dtls-enable
      |  +-- babel-if-dtls-cert-sets
      |  +-- babel-dtls-cached-info
      |  +-- babel-dtls-cert-prefer

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      |  +-- babel-packet-log-enable
      |  +-- babel-packet-log
      |  +-- babel-if-stats
      |  |  +-- babel-sent-mcast-hello
      |  |  +-- babel-sent-mcast-update
      |  |  +-- babel-received-packets
      |  +-- babel-neighbors
      |  |  +-- babel-neighbor-address
      |  |  +-- babel-hello-mcast-history
      |  |  +-- babel-hello-ucast-history
      |  |  +-- babel-txcost
      |  |  +-- babel-exp-mcast-hello-seqno
      |  |  +-- babel-exp-ucast-hello-seqno
      |  |  +-- babel-ucast-hello-seqno
      |  |  +-- babel-ucast-hello-interval
      |  |  +-- babel-rxcost
      |  |  +-- babel-cost
      |  |  +-- babel-nbr-stats
      |  |  |  +-- babel-sent-ucast-hello
      |  |  |  +-- babel-sent-ucast-update
      |  |  |  +-- babel-sent-IHU
      |  |  |  +-- babel-received-hello
      |  |  |  +-- babel-received-update
      |  |  |  +-- babel-received-IHU
      +-- babel-routes
      |  +-- babel-route-prefix
      |  +-- babel-route-prefix-length
      |  +-- babel-route-router-id
      |  +-- babel-route-neighbor
      |  +-- babel-route-received-metric
      |  +-- babel-route-calculated-metric
      |  +-- babel-route-seqno
      |  +-- babel-route-next-hop
      |  +-- babel-route-feasible
      |  +-- babel-route-selected
      +-- babel-hmac-key-sets
      |  +-- babel-hmac-default-apply
      |  +-- babel-hmac-keys
      |  |  +-- babel-hmac-key-name
      |  |  +-- babel-hmac-key-use-sign
      |  |  +-- babel-hmac-key-use-verify
      |  |  +-- babel-hmac-key-value
      +-- babel-dtls-cert-sets
      |  +-- babel-dtls-default-apply
      |  +-- babel-dtls-certs
      |  |  +-- babel-cert-name
      |  |  +-- babel-cert-value
      |  |  +-- babel-cert-type

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      |  |  +-- babel-cert-private-key
      |  |  +-- babel-cert-test

   Most parameters are read-only.  Following is a descriptive list of
   the parameters that are not required to be read-only:

   o  enable/disable Babel

   o  create/delete babel-hmac objects

   o  create/delete babel-dtls objects

   o  enable/disable statistics collection

   o  Constant: UDP port

   o  Constant: IPv6 multicast group

   o  Interface: Link type

   o  Interface: enable/disable Babel on this interface

   o  Interface: sets of HMAC keys

   o  Interface: HMAC algorithm

   o  Interface: verify received HMAC packets

   o  Interface: set of DTLS certificates

   o  Interface: use cached info extensions

   o  Interface: preferred order of certificate types

   o  Interface: enable/disable packet log

   o  HMAC-keys: create/delete entries

   o  HMAC-keys: use to sign packets

   o  HMAC-keys: use to verify packets

   o  DTLS-certs: create/delete entries

   The following parameters are required to return no value when read:

   o  HMAC key values

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   o  DTLS certificate values

   Note that this overview is intended simply to be informative and is
   not normative.  If there is any discrepancy between this overview and
   the detailed information model definitions in subsequent sections,
   the error is in this overview.

3.  The Information Model

3.1.  Definition of babel-information-obj

     object {
          string               ro babel-implementation-version;
          boolean              rw babel-enable;
          binary               ro babel-self-router-id;
         [uint                 ro babel-self-seqno;]
          string               ro babel-metric-comp-algorithms<1..*>;
          string               ro babel-security-supported<0..*>;
         [string               ro babel-hmac-algorithms<1..*>;]
         [string               ro babel-dtls-cert-types<1..*>;]
         [boolean              rw babel-stats-enable;]
         [operation               babel-stats-reset;]
          babel-constants-obj  ro babel-constants;
          babel-interfaces-obj ro babel-interfaces<0..*>;
          babel-routes-obj     ro babel-routes<0..*>;
         [babel-hmac-obj       rw babel-hmac<0..*>;]
         [babel-dtls-obj       rw babel-dtls<0..*>;]
      } babel-information-obj;

   babel-implementation-version:  The name and version of this
      implementation of the Babel protocol.

   babel-enable:  When written, it configures whether the protocol
      should be enabled (true) or disabled (false).  A read from the
      running or intended datastore indicates the configured
      administrative value of whether the protocol is enabled (true) or
      not (false).  A read from the operational datastore indicates
      whether the protocol is actually running (true) or not (i.e., it
      indicates the operational state of the protocol).  A data model
      that does not replicate parameters for running and operational
      datastores can implement this as two separate parameters.  An
      implementation MAY choose to expose this parameter as read-only
      ("ro").

   babel-self-router-id:  The router-id used by this instance of the
      Babel protocol to identify itself.  [I-D.ietf-babel-rfc6126bis]
      describes this as an arbitrary string of 8 octets.  The router-id
      value MUST NOT consist of all zeroes or all ones.

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   babel-self-seqno:  The current sequence number included in route
      updates for routes originated by this node.  This is a 16-bit
      unsigned integer.

   babel-metric-comp-algorithms:  List of supported cost computation
      algorithms.  Possible values include "2-out-of-3", and "ETX".

   babel-security-supported:  List of supported security mechanisms.
      Possible values include "HMAC" and "DTLS".

   babel-hmac-algorithms:  List of supported HMAC computation
      algorithms.  Possible values include "HMAC-SHA256", "BLAKE2s".

   babel-dtls-cert-types:  List of supported DTLS certificate types.
      Possible values include "X.509" and "RawPublicKey".

   babel-stats-enable:  Indicates whether statistics collection is
      enabled (true) or disabled (false) on all interfaces, including
      neighbor-specific statistics (babel-nbr-stats).

   babel-stats-reset:  An operation that resets all babel-if-stats and
      babel-nbr-stats parameters to zero.  This operation has no input
      or output parameters.

   babel-constants:  A babel-constants-obj object.

   babel-interfaces:  A set of babel-interface-obj objects.

   babel-routes:  A set of babel-route-obj objects.  Contains the routes
      known to this node.

   babel-hmac:  A babel-hmac-obj object.  If this object is implemented,
      it provides access to parameters related to the HMAC security
      mechanism.  An implementation MAY choose to expose this object as
      read-only ("ro").

   babel-dtls:  A babel-dtls-obj object.  If this object is implemented,
      it provides access to parameters related to the DTLS security
      mechanism.  An implementation MAY choose to expose this object as
      read-only ("ro").

3.2.  Definition of babel-constants-obj

     object {
          uint         rw babel-udp-port;
         [ip-address   rw babel-mcast-group;]
      } babel-constants-obj;

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   babel-udp-port:  UDP port for sending and listening for Babel
      packets.  Default is 6696.  An implementation MAY choose to expose
      this parameter as read-only ("ro").  This is a 16-bit unsigned
      integer.

   babel-mcast-group:  Multicast group for sending and listening to
      multicast announcements on IPv6.  Default is ff02:0:0:0:0:0:1:6.
      An implementation MAY choose to expose this parameter as read-only
      ("ro").

3.3.  Definition of babel-interfaces-obj

     object {
          reference            ro babel-interface-reference;
         [boolean              rw babel-interface-enable;]
          string               rw babel-interface-metric-algorithm;
          boolean              rw babel-interface-split-horizon;
         [uint                 ro babel-mcast-hello-seqno;]
         [uint                 ro babel-mcast-hello-interval;]
         [uint                 ro babel-update-interval;]
         [boolean              rw babel-hmac-enable;]
         [reference            rw babel-if-hmac-key-sets<0..*>;]
         [string               rw babel-hmac-algorithm;]
         [boolean              rw babel-hmac-verify;]
         [boolean              rw babel-dtls-enable;]
         [reference            rw babel-if-dtls-cert-sets<0..*>;]
         [boolean              rw babel-dtls-cached-info;]
         [string               rw babel-dtls-cert-prefer<0..*>;]
         [boolean              rw babel-packet-log-enable;]
         [reference            ro babel-packet-log;]
         [babel-if-stats-obj   ro babel-if-stats;]
          babel-neighbors-obj  ro babel-neighbors<0..*>;
      } babel-interfaces-obj;

   babel-interface-reference:  Reference to an IPv6 interface object as
      defined by the data model (e.g., YANG [RFC7950], BBF [TR-181]).
      Referencing syntax will be specific to the data model.  If there
      is no set of interface objects available, this should be a string
      that indicates the interface name used by the underlying operating
      system.

   babel-interface-enable:  When written, it configures whether the
      protocol should be enabled (true) or disabled (false) on this
      interface.  A read from the running or intended datastore
      indicates the configured administrative value of whether the
      protocol is enabled (true) or not (false).  A read from the
      operational datastore indicates whether the protocol is actually
      running (true) or not (i.e., it indicates the operational state of

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      the protocol).  A data model that does not replicate parameters
      for running and operational datastores can implement this as two
      separate parameters.  An implementation MAY choose to expose this
      parameter as read-only ("ro").

   babel-interface-metric-algorithm:  Indicates the metric computation
      algorithm used on this interface.  The value MUST be one of those
      listed in the babel-information-obj babel-metric-comp-algorithms
      parameter.  An implementation MAY choose to expose this parameter
      as read-only ("ro").

   babel-interface-split-horizon:  Indicates whether or not the split
      horizon optimization is used when calculating metrics on this
      interface.  A value of true indicates split horizon optimization
      is used.

   babel-mcast-hello-seqno:  The current sequence number in use for
      multicast Hellos sent on this interface.  This is a 16-bit
      unsigned integer.

   babel-mcast-hello-interval:  The current interval in use for
      multicast Hellos sent on this interface.  Units are centiseconds.
      This is a 16-bit unsigned integer.

   babel-update-interval:  The current interval in use for all updates
      (multicast and unicast) sent on this interface.  Units are
      centiseconds.  This is a 16-bit unsigned integer.

   babel-hmac-enable:  Indicates whether the HMAC security mechanism is
      enabled (true) or disabled (false).  An implementation MAY choose
      to expose this parameter as read-only ("ro").

   babel-if-hmac-keys-sets:  List of references to the babel-hmac
      entries that apply to this interface.  When an interface instance
      is created, all babel-hmac-key-sets instances with babel-hmac-
      default-apply "true" will be included in this list.  An
      implementation MAY choose to expose this parameter as read-only
      ("ro").

   babel-hmac-algorithm  The name of the HMAC algorithm used on this
      interface.  The value MUST be the same as one of the enumerations
      listed in the babel-hmac-algorithms parameter.  An implementation
      MAY choose to expose this parameter as read-only ("ro").

   babel-hmac-verify  A Boolean flag indicating whether HMAC hashes in
      incoming Babel packets are required to be present and are
      verified.  If this parameter is "true", incoming packets are

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      required to have a valid HMAC hash.  An implementation MAY choose
      to expose this parameter as read-only ("ro").

   babel-dtls-enable:  Indicates whether the DTLS security mechanism is
      enabled (true) or disabled (false).  An implementation MAY choose
      to expose this parameter as read-only ("ro").

   babel-if-dtls-cert-sets:  List of references to the babel-dtls-cert-
      sets entries that apply to this interface.  When an interface
      instance is created, all babel-dtls-cert-sets instances with
      babel-dtls-default-apply "true" will be included in this list.  An
      implementation MAY choose to expose this parameter as read-only
      ("ro").

   babel-dtls-cached-info:  Indicates whether the cached_info extension
      is included in ClientHello and ServerHello packets.  The extension
      is included if the value is "true".  An implementation MAY choose
      to expose this parameter as read-only ("ro").

   babel-dtls-cert-prefer:  List of supported certificate types, in
      order of preference.  The values MUST be among those listed in the
      babel-dtls-cert-types parameter.  This list is used to populate
      the server_certificate_type extension in a Client Hello.  Values
      that are present in at least one instance in the babel-dtls-certs
      object of a referenced babel-dtls instance and that have a non-
      empty babel-cert-private-key will be used to populate the
      client_certificate_type extension in a Client Hello.

   babel-packet-log-enable:  Indicates whether packet logging is enabled
      (true) or disabled (false) on this interface.

   babel-packet-log:  A reference or url link to a file that contains a
      timestamped log of packets received and sent on babel-udp-port on
      this interface.  The [libpcap] file format with .pcap file
      extension SHOULD be supported for packet log files.  Logging is
      enabled / disabled by babel-packet-log-enable.

   babel-if-stats:  Statistics collection object for this interface.

   babel-neighbors:  A set of babel-neighbors-obj objects.

3.4.  Definition of babel-if-stats-obj

     object {
          uint                 ro babel-sent-mcast-hello;
          uint                 ro babel-sent-mcast-update;
          uint                 ro babel-received-packets;
      } babel-if-stats-obj;

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   babel-sent-mcast-hello:  A count of the number of multicast Hello
      packets sent on this interface.

   babel-sent-mcast-update:  A count of the number of multicast update
      packets sent on this interface.

   babel-received-packets:  A count of the number of Babel packets
      received on this interface.

3.5.  Definition of babel-neighbors-obj

     object {
          ip-address          ro babel-neighbor-address;
         [binary              ro babel-hello-mcast-history;]
         [binary              ro babel-hello-ucast-history;]
          uint                ro babel-txcost;
          uint                ro babel-exp-mcast-hello-seqno;
          uint                ro babel-exp-ucast-hello-seqno;
         [uint                ro babel-ucast-hello-seqno;]
         [uint                ro babel-ucast-hello-interval;]
         [uint                ro babel-rxcost;]
         [uint                ro babel-cost;]
         [babel-nbr-stats-obj ro babel-nbr-stats;]
      } babel-neighbors-obj;

   babel-neighbor-address:  IPv4 or IPv6 address the neighbor sends
      packets from.

   babel-hello-mcast-history:  The multicast Hello history of whether or
      not the multicast Hello packets prior to babel-exp-mcast-hello-
      seqno were received.  A binary sequence where the most recently
      received Hello is expressed as a "1" placed in the left-most bit,
      with prior bits shifted right (and "0" bits placed between prior
      Hello bits and most recent Hello for any not-received Hellos).
      This value should be displayed using hex digits ([0-9a-fA-F]).
      See [I-D.ietf-babel-rfc6126bis], section A.1.

   babel-hello-ucast-history:  The unicast Hello history of whether or
      not the unicast Hello packets prior to babel-exp-ucast-hello-seqno
      were received.  A binary sequence where the most recently received
      Hello is expressed as a "1" placed in the left-most bit, with
      prior bits shifted right (and "0" bits placed between prior Hello
      bits and most recent Hello for any not-received Hellos).  This
      value should be displayed using hex digits ([0-9a-fA-F]).  See
      [I-D.ietf-babel-rfc6126bis], section A.1.

   babel-txcost:  Transmission cost value from the last IHU packet
      received from this neighbor, or maximum value to indicate the IHU

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      hold timer for this neighbor has expired.  See
      [I-D.ietf-babel-rfc6126bis], section 3.4.2.  This is a 16-bit
      unsigned integer.

   babel-exp-mcast-hello-seqno:  Expected multicast Hello sequence
      number of next Hello to be received from this neighbor.  If
      multicast Hello packets are not expected, or processing of
      multicast packets is not enabled, this MUST be 0.  This is a
      16-bit unsigned integer.

   babel-exp-ucast-hello-seqno:  Expected unicast Hello sequence number
      of next Hello to be received from this neighbor.  If unicast Hello
      packets are not expected, or processing of unicast packets is not
      enabled, this MUST be 0.  This is a 16-bit unsigned integer.

   babel-ucast-hello-seqno:  The current sequence number in use for
      unicast Hellos sent to this neighbor.  This is a 16-bit unsigned
      integer.

   babel-ucast-hello-interval:  The current interval in use for unicast
      Hellos sent to this neighbor.  Units are centiseconds.  This is a
      16-bit unsigned integer.

   babel-rxcost:  Reception cost calculated for this neighbor.  This
      value is usually derived from the Hello history, which may be
      combined with other data, such as statistics maintained by the
      link layer.  The rxcost is sent to a neighbor in each IHU.  See
      [I-D.ietf-babel-rfc6126bis], section 3.4.3.  This is a 16-bit
      unsigned integer.

   babel-cost:  Link cost is computed from the values maintained in the
      neighbor table: the statistics kept in the neighbor table about
      the reception of Hellos, and the txcost computed from received IHU
      packets.  This is a 16-bit unsigned integer.

   babel-nbr-stats:  Statistics collection object for this neighbor.

3.6.  Definition of babel-nbr-stats-obj

     object {
          uint                 ro babel-sent-ucast-hello;
          uint                 ro babel-sent-ucast-update;
          uint                 ro babel-sent-IHU;
          uint                 ro babel-received-hello;
          uint                 ro babel-received-update;
          uint                 ro babel-received-IHU;
      } babel-nbr-stats-obj;

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   babel-sent-ucast-hello:  A count of the number of unicast Hello
      packets sent to this neighbor.

   babel-sent-ucast-update:  A count of the number of unicast update
      packets sent to this neighbor.

   babel-sent-IHU:  A count of the number of IHU packets sent to this
      neighbor.

   babel-received-hello:  A count of the number of Hello packets
      received from this neighbor.

   babel-received-update:  A count of the number of update packets
      received from this neighbor.

   babel-received-IHU:  A count of the number of IHU packets received
      from this neighbor.

3.7.  Definition of babel-routes-obj

     object {
          ip-address           ro babel-route-prefix;
          uint                 ro babel-route-prefix-length;
          binary               ro babel-route-router-id;
          string               ro babel-route-neighbor;
          uint                 ro babel-route-received-metric;
          uint                 ro babel-route-calculated-metric;
          uint                 ro babel-route-seqno;
          ip-address           ro babel-route-next-hop;
          boolean              ro babel-route-feasible;
          boolean              ro babel-route-selected;
      } babel-routes-obj;

   babel-route-prefix:  Prefix (expressed in IP address format) for
      which this route is advertised.

   babel-route-prefix-length:  Length of the prefix for which this route
      is advertised.

   babel-route-router-id:  router-id of the source router for which this
      route is advertised.

   babel-route-neighbor:  Reference to the babel-neighbors entry for the
      neighbor that advertised this route.

   babel-route-received-metric:  The metric with which this route was
      advertised by the neighbor, or maximum value to indicate the route
      was recently retracted and is temporarily unreachable (see

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      Section 3.5.5 of [I-D.ietf-babel-rfc6126bis]).  This metric will
      be 0 (zero) if the route was not received from a neighbor but was
      generated through other means.  At least one of babel-route-
      calculated-metric and babel-route-received-metric MUST be non-
      zero.  Having both be non-zero is expected for a route that is
      received and subsequently advertised.  This is a 16-bit unsigned
      integer; if the data model uses zero (0) to represent NULL values
      for unsigned integers, the data model may use a different data
      type that allows differentiation between zero (0) and NULL.

   babel-route-calculated-metric:  A calculated metric for this route.
      How the metric is calculated is implementation-specific.  Maximum
      value indicates the route was recently retracted and is
      temporarily unreachable (see Section 3.5.5 of
      [I-D.ietf-babel-rfc6126bis]).  At least one of babel-route-
      calculated-metric and babel-route-received-metric MUST be non-
      zero.  Having both be non-zero is expected for a route that is
      received and subsequently advertised.  This is a 16-bit unsigned
      integer; but it may be represented by a data model as a signed
      integer for schemas that use 0 (zero) to represent NULL with
      unsigned integers and use negative numbers to represent NULL with
      signed integers.

   babel-route-seqno:  The sequence number with which this route was
      advertised.  This is a 16-bit unsigned integer.

   babel-route-next-hop:  The next-hop address of this route.  This will
      be empty if this route has no next-hop address.

   babel-route-feasible:  A Boolean flag indicating whether this route
      is feasible, as defined in Section 3.5.1 of
      [I-D.ietf-babel-rfc6126bis]).

   babel-route-selected:  A Boolean flag indicating whether this route
      is selected (i.e., whether it is currently being used for
      forwarding and is being advertised).

3.8.  Definition of babel-hmac-key-sets-obj

     object {
          boolean               rw babel-hmac-default-apply;
          babel-hmac-keys-obj   rw babel-hmac-keys<0..*>;
      } babel-hmac-obj;

   babel-hmac-default-apply:  A Boolean flag indicating whether this
      babel-hmac instance is applied to all new babel-interface
      instances, by default.  If "true", this instance is applied to new
      babel-interfaces instances at the time they are created, by

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      including it in the babel-interface-hmac-keys list.  If "false",
      this instance is not applied to new babel-interfaces instances
      when they are created.  An implementation MAY choose to expose
      this parameter as read-only ("ro").

   babel-hmac-keys:  A set of babel-hmac-keys-obj objects.

3.9.  Definition of babel-hmac-keys-obj

     object {
          string                rw babel-hmac-key-name;
          boolean               rw babel-hmac-key-use-sign;
          boolean               rw babel-hmac-key-use-verify;
          binary                -- babel-hmac-key-value;
         [operation                babel-hmac-key-test;]
      } babel-hmac-keys-obj;

   babel-hmac-key-name:  A unique name for this HMAC key that can be
      used to identify the key in this object instance, since the key
      value is not allowed to be read.  This value MUST NOT be empty and
      can only be provided when this instance is created (i.e., it is
      not subsequently writable).  The value MAY be auto-generated if
      not explicitly supplied when the instance is created.

   babel-key-use-sign:  Indicates whether this key value is used to sign
      sent Babel packets.  Sent packets are signed using this key if the
      value is "true".  If the value is "false", this key is not used to
      sign sent Babel packets.  An implementation MAY choose to expose
      this parameter as read-only ("ro").

   babel-key-use-verify:  Indicates whether this key value is used to
      verify incoming Babel packets.  This key is used to verify
      incoming packets if the value is "true".  If the value is "false",
      no HMAC is computed from this key for comparing an incoming
      packet.  An implementation MAY choose to expose this parameter as
      read-only ("ro").

   babel-key-value:  The value of the HMAC key.  An implementation MUST
      NOT allow this parameter to be read.  This can be done by always
      providing an empty string, or through permissions, or other means.
      This value MUST be provided when this instance is created, and is
      not subsequently writable.

   babel-hmac-test:  An operation that allows the HMAC key and hash
      algorithm to be tested to see if they produce an expected outcome.
      Input to this operation MUST be a non-empty binary string.  The
      implementation is expected to create a hash of this string using

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      the babel-hmac-key-value and the babel-hmac-algorithm.  The output
      of this operation is the resulting hash, as a binary string.

3.10.  Definition of babel-dtls-cert-sets-obj

     object {
          boolean               rw babel-dtls-default-apply;
          babel-dtls-certs-obj  rw babel-dtls-certs<0..*>;
      } babel-dtls-obj;

   babel-dtls-default-apply:  A Boolean flag indicating whether this
      babel-dtls instance is applied to all new babel-interface
      instances, by default.  If "true", this instance is applied to new
      babel-interfaces instances at the time they are created, by
      including it in the babel-interface-dtls-certs list.  If "false",
      this instance is not applied to new babel-interfaces instances
      when they are created.  An implementation MAY choose to expose
      this parameter as read-only ("ro").

   babel-dtls-certs:  A set of babel-dtls-keys-obj objects.  This
      contains both certificates for this implementation to present for
      authentication, and to accept from others.  Certificates with a
      non-empty babel-cert-private-key can be presented by this
      implementation for authentication.

3.11.  Definition of babel-dtls-certs-obj

     object {
          string                rw babel-cert-name;
          string                rw babel-cert-value;
          string                rw babel-cert-type;
          binary                -- babel-cert-private-key;
         [operation                babel-cert-test;]
      } babel-dtls-certs-obj;

   babel-cert-name:  A unique name for this DTLS certificate that can be
      used to identify the certificate in this object instance, since
      the value is too long to be useful for identification.  This value
      MUST NOT be empty and can only be provided when this instance is
      created (i.e., it is not subsequently writable).  The value MAY be
      auto-generated if not explicitly supplied when the instance is
      created.

   babel-cert-value:  The DTLS certificate in PEM format [RFC7468].
      This value MUST be provided when this instance is created, and is
      not subsequently writable.

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   babel-cert-type:  The name of the certificate type of this object
      instance.  The value MUST be the same as one of the enumerations
      listed in the babel-dtls-cert-types parameter.  This value can
      only be provided when this instance is created, and is not
      subsequently writable.

   babel-cert-private-key:  The value of the private key.  If this is
      non-empty, this certificate can be used by this implementation to
      provide a certificate during DTLS handshaking.  An implementation
      MUST NOT allow this parameter to be read.  This can be done by
      always providing an empty string, or through permissions, or other
      means.  This value can only be provided when this instance is
      created, and is not subsequently writable.

   babel-cert-test:  An operation that allows a hash of the provided
      input string to be created using the certificate public key and
      the SHA-256 hash algorithm.  Input to this operation MUST be a
      non-empty binary string.  The output of this operation is the
      resulting hash, as a binary string.

4.  Extending the Information Model

   Implementations MAY extend this information model with other
   parameters or objects.  For example, an implementation MAY choose to
   expose Babel route filtering rules by adding a route filtering object
   with parameters appropriate to how route filtering is done in that
   implementation.  The precise means used to extend the information
   model would be specific to the data model the implementation uses to
   expose this information.

5.  Security Considerations

   This document defines a set of information model objects and
   parameters that may be exposed to be visible from other devices, and
   some of which may be configured.  Securing access to and ensuring the
   integrity of this data is in scope of and the responsibility of any
   data model derived from this information model.  Specifically, any
   YANG [RFC7950] data model is expected to define security exposure of
   the various parameters, and a [TR-181] data model will be secured by
   the mechanisms defined for the management protocol used to transport
   it.

   This information model defines objects that can allow credentials
   (for this device, for trusted devices, and for trusted certificate
   authorities) to be added and deleted.  Public keys and shared secrets
   may be exposed through this model.  This model requires that private
   keys never be exposed.  The Babel security mechanisms that make use
   of these credentials (e.g., [I-D.ietf-babel-dtls],

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   [I-D.ietf-babel-hmac]) are expected to define what credentials can be
   used with those mechanisms.

6.  Acknowledgements

   Juliusz Chroboczek, Toke Hoeiland-Joergensen, David Schinazi, Acee
   Lindem, and Carsten Bormann have been very helpful in refining this
   information model.

   The language in the Notation section was mostly taken from [RFC8193].

7.  References

7.1.  Normative References

   [I-D.ietf-babel-rfc6126bis]
              Chroboczek, J. and D. Schinazi, "The Babel Routing
              Protocol", draft-ietf-babel-rfc6126bis-11 (work in
              progress), June 2019.

   [libpcap]  Wireshark, "Libpcap File Format", 2015,
              <https://wiki.wireshark.org/Development/
              LibpcapFileFormat>.

   [RFC0020]  Cerf, V., "ASCII format for network interchange", STD 80,
              RFC 20, DOI 10.17487/RFC0020, October 1969,
              <https://www.rfc-editor.org/info/rfc20>.

   [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>.

   [RFC7468]  Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
              PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
              April 2015, <https://www.rfc-editor.org/info/rfc7468>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [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>.

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7.2.  Informative References

   [I-D.ietf-babel-dtls]
              Decimo, A., Schinazi, D., and J. Chroboczek, "Babel
              Routing Protocol over Datagram Transport Layer Security",
              draft-ietf-babel-dtls-07 (work in progress), July 2019.

   [I-D.ietf-babel-hmac]
              Do, C., Kolodziejak, W., and J. Chroboczek, "HMAC
              authentication for the Babel routing protocol", draft-
              ietf-babel-hmac-08 (work in progress), July 2019.

   [ISO.10646]
              International Organization for Standardization,
              "Information Technology - Universal Multiple-Octet Coded
              Character Set (UCS)", ISO Standard 10646:2014, 2014.

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
              <https://www.rfc-editor.org/info/rfc3339>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [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>.

   [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>.

   [RFC8193]  Burbridge, T., Eardley, P., Bagnulo, M., and J.
              Schoenwaelder, "Information Model for Large-Scale
              Measurement Platforms (LMAPs)", RFC 8193,
              DOI 10.17487/RFC8193, August 2017,
              <https://www.rfc-editor.org/info/rfc8193>.

   [TR-181]   Broadband Forum, "Device Data Model",
              <http://cwmp-data-models.broadband-forum.org/>.

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Appendix A.  Open Issues

   All open issues have been closed.

   Closed Issues:

   1.   See minutes of IETF 104 for discussion of issues that led to
        changes noted for 2019-07-08

   2.   HMAC spec adds other parameters to neighbor table.  Check these
        to see if any need to be readable or writable. / None were
        identified.

   3.   Actions to add and delete HMAC and DTLS credentials, and
        parameters that allow credential to be identified without
        allowing access to private credential info.  Will have separate
        sub-tables for HMAC and DTLS credentials. / Instead, there is a
        normative statement that the parameter values must never be
        supplied when read.

   4.   Consider the following statistics: under interface object: sent
        multicast Hello, sent updates, received Babel messages; under
        neighbor object: sent unicast Hello, sent updates, sent IHU,
        received Hello, received updates, received IHUs.  Would also
        need to enable/disable stats and clear stats.

   5.   Message log (optional to implement) is still in.  Support for
        the libpcap file format is "SHOULD".

   6.   Single security table with (optional) reference to interfaces
        that security mechanism applies to. / This actually became
        separate objects for DTLS and HMAC.

   7.   Should ABNF be normative in IANA Considerations section?
        Decision was to leave it as is.

   8.   I want to get rid of the security log, because all Babel
        messages (which should be defined as all messages to/from the
        udp-port) are be logged by message-log.  I don't like message
        log as it is.  I think if logging is enabled it should just
        write to a text file.  This will mean there also needs to be a
        means of downloading/reading the log file.  Closed by having
        single log for all messages to/from udp port and log is
        represented by a string that can be reference to filename or
        some other part of the overall data model (depends on data
        model).

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   9.   Check description of enable parameters to make sure ok for YANG
        and TR-181.  Closed by updating description to be useful for
        YANG and TR-181, using language consistent with YANG
        descriptions.  Done.

   10.  Distinguish signed and unsigned integers?  All integers are
        unsigned and size is mentioned in description of each uint
        parameter.

   11.  Datatype of the router-id: Closed by introducing binary datatype
        and using that for router-id

   12.  babel-neighbor-address as IPv6-only: Closed by leaving as is
        (IPv4 and IPv6)

   13.  babel-implementation-version includes the name of the
        implementation: Closed by adding "name" to description

   14.  Delete external-cost?: Closed by deleting.

   15.  Would it be useful to define some parameters for reporting
        statistics or logs? [2 logs are now included.  If others are
        needed they need to be proposed.  See Open Issues for additional
        thoughts on logs and statistics.]

   16.  Closed by defining base64 type and using it for all router IDs:
        "babel-self-router-id: Should this be an opaque 64-bit value
        instead of int?"

   17.  Closed as "No": Do we need a registry for the supported security
        mechanisms?  [Given the current limited set, and unlikelihood of
        massive expansion, I don't think so.  But we can if someone
        wants it.]

   18.  This draft must be reviewed against draft-ietf-babel-rfc6126bis.
        [I feel like this has been adequately done, but I could be
        wrong.]

   19.  babel-interfaces-obj: Juliusz:"This needs further discussion, I
        fear some of these are implementation details."  [In the absence
        of discussion, the current model stands.  Note that all but
        link-type and the neighbors sub-object are optional.  If an
        implementation does not have any of the optional elements then
        it simply doesn't have them and that's fine.]

   20.  Would it be useful to define some parameters specifically for
        security anomalies?  [The 2 logs should be useful in identifying

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        security anomalies.  If more is needed, someone needs to
        propose.]

   21.  I created a basic security model.  It's useful for single (or
        no) active security mechanism (e.g., just HMAC, just DTLS, or
        neither); but not multiple active (both HMAC and DTLS -- which
        is not the same as HMAC of DTLS and would just mean that HMAC
        would be used on all unencrypted messages -- but right now the
        model doesn't allow for configuring HMAC of unencrypted messages
        for routers without DTLS, while DTLS is used if possible).  OK?
        [No-one said otherwise.]

   22.  babel-external-cost may need more work. [if no comment, it will
        be left as is]

   23.  babel-hello-[mu]cast-history: the Hello history is formated as
        16 bits, per A.1 of 6126bis.  Is that a too implementation
        specific?  [We also now have an optional-to-implement log of
        received messages, and I made these optional.  So maybe this is
        ok?]

   24.  rxcost, txcost, cost: is it ok to model as integers, since
        6126bis 2.1 says costs and metrics need not be integers.  [I
        have them as integers unless someone insists on something else.]

   25.  For the security log, should it also log whether the credentials
        were considered ok?  [Right now it doesn't and I think that's ok
        because if you log Hellos it was ok and if you don't it wasn't.]

   26.  Should Babel link types have an IANA registry?  [Agreed to do
        this at IETF 102.]

Appendix B.  Change Log

   Individual Drafts:

   v00 2016-07-07  EBD:  Initial individual draft version

   v01 2017-03-13:  Addressed comments received in 2016-07-15 email from
      J.  Chroboczek

   Working group drafts:

   v00 2017-07-03:  Addressed points noted with "oops" in
      https://www.ietf.org/proceedings/98/slides/slides-98-babel-babel-
      information-model-00.pdf

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   v01 2018-01-02:  Removed item from issue list that was agreed (in
      Prague) not to be an issue.  Added description of data types under
      Notation section, and used these in all data types.  Added babel-
      security and babel-trust.

   v02 2018-04-05:

      *  changed babel-version description to babel-implementation-
         version

      *  replace optional babel-interface-seqno with optional babel-
         mcast-hello-seqno and babel-ucast-hello-seqno

      *  replace optional babel-interface-hello-interval with optional
         babel-mcast-hello-interval and babel-ucast-hello-interval

      *  remove babel-request-trigger-ack

      *  remove "babel-router-id: router-id of the neighbor"; note that
         parameter had previously been removed but description had
         accidentally not been removed

      *  added an optional "babel-cost" field to babel-neighbors object,
         since the spec does not define how exactly the cost is computed
         from rxcost/txcost

      *  deleted babel-source-garbage-collection-time

      *  change babel-lossy-link to babel-link-type and make this an
         enumeration; added at top level babel-supported-link-types so
         which are supported by this implementation can be reported

      *  changes to babel-security-obj to allow self credentials to be
         one or more instances of a credential object.  Allowed trusted
         credentials to include CA credentials; made some parameter name
         changes

      *  updated references and Introduction

      *  added Overview section

      *  deleted babel-sources-obj

      *  added feasible Boolean to routes

      *  added section to briefly describe extending the information
         model.

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      *  deleted babel-route-neighbor

      *  tried to make definition of babel-interface-reference clearer

      *  added security and message logs

   v03 2018-05-31:

      *  added reference to RFC 8174 (update to RFC 2119 on key words)

      *  applied edits to Introduction text per Juliusz email of
         2018-04-06

      *  Deleted sentence in definition of "int" data type that said it
         was also used for enumerations.  Changed all enumerations to
         strings.  The only enumerations were for link types, which are
         now "ethernet", "wireless", "tunnel", and "other".

      *  deleted [ip-address babel-mcast-group-ipv4;]

      *  babel-external-cost description changed

      *  babel-security-self-cred: Added "any private key component of a
         credential MUST NOT be readable;"

      *  hello-history parameters put recent Hello in most significant
         bit and length of parameter is not constrained.

      *  babel-hello-seqno in neighbors-obj changed to babel-exp-mcast-
         hello-seqno and babel-exp-ucast-hello-seqno

      *  added babel-route-neighbor back again.  It was mistakenly
         deleted

      *  changed babel-route-metric and babel-route-announced-metric to
         babel-route-received-metric and babel-route-calculated-metric

      *  changed model of security object to put list of supported
         mechanisms at top level and separate security object per
         mechanism.  This caused some other changes to the security
         object

   v04 2018-10-15:

      *  changed babel-mcast-group-ipv6 to babel-mcast-group

      *  link type parameters changed to point to newly defined registry

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      *  babel-ucast-hello-interval moved to neighbor object

      *  babel-ucast-hello-seqno moved to neighbor object

      *  babel-neighbor-ihu-interval deleted

      *  in log descriptions, included statement that there SHOULD be
         ability to clear logs

      *  added IANA registry for link types

      *  added "ro" and "rw" to tables for read-write and read-only

      *  added metric computation parameter to interface

   v05 2019-01-15:

      *  security modeled with single table under information-obj and
         references to interfaces that instance applies to

      *  changed int to uint because all integers in model were
         unsigned; added size of integer to description of each uint
         parameter

      *  deleted log object and made single message log that points to
         file or other data model object used to maintain logs

      *  deleted babel-credentials; there are no more "common" objects;
         hmac keys and DTLS certificates are more explicitly modeled

      *  changed definition of babel-security-supported

      *  added parameters for HMAC and DTLS

      *  added statistics

      *  changed all instances of "message" to "packet"

   v06 2019-07-08:

      *  changed Link Type registry in IANA considerations to Lik
         Property Types

      *  changed direction of reference for HMAC and DTLS objects to be
         from interface to these objects

      *  provided DTLS certificate objects with a unique name

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      *  changed received and calculated metric descriptions to make
         clear that it is ok to have both

      *  constrained interface reference to only IPv6 interfaces

   v07 2019-07-22:

      *  babel-dtls-enable and babel-hmac-enable moved to interfaces and
         made rw

      *  renamed babel-dtls and babel-hmac to babel-dtls-cert-sets and
         babel-hmac-key-sets and references to them from interfaces are
         babel-if-dtls-cert-sets and babel-if-hmac-key-sets

      *  https://github.com/bhstark2/babel-information-model/issues/16
         with nits

      *  https://github.com/bhstark2/babel-information-model/issues/14
         addressing parameters not allowed to be empty/null

      *  https://github.com/bhstark2/babel-information-model/issues/18
         on IANA link properties table

   v08 2019-08-04:

      *  Deleted IANA Considerations section

      *  Deleted babel-supported-link-properties and babel-link-
         properties in all places3

      *  Made babel-interface-metric-algorithm rw

      *  Added boolean rw babel-interface-split-horizon parameter

      *  Replaced the "k-out-of-j" enumeration for expression of
         algorithmic capabilities with "2-out-of-3"

      *  Calculated and received metrics datatype can be signed int if
         needed to represent NULL value

Authors' Addresses

   Barbara Stark
   AT&T
   Atlanta, GA
   US

   Email: barbara.stark@att.com

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   Mahesh Jethanandani
   VMware
   California
   US

   Email: mjethanandani@gmail.com

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