intarea                                                       P. Pfister
Internet-Draft                                            E. Vyncke, Ed.
Intended status: Standards Track                                   Cisco
Expires: May 3, August 13, 2018                                        T. Pauly
                                                             D. Schinazi
                                                                   Apple
                                                                M. Keane
                                                               Microsoft
                                                        October 30, 2017
                                                        February 9, 2018

             Discovering Provisioning Domain Names and Data
               draft-ietf-intarea-provisioning-domains-00
               draft-ietf-intarea-provisioning-domains-01

Abstract

   An increasing number of hosts and networks are connected to access the Internet through multiple interfaces, some of which may provide via multiple ways to access the internet by means of
   interfaces or, in IPv6 multi-homed networks, via multiple IPv6 prefix
   configurations.

   This document describes a way for hosts to retrieve additional
   information about their network access characteristics.  The set of
   configuration items required to access the Internet is identify such means,
   called a Provisioning Domain (PvD).  The PvD is identified by a Domains (PvDs), with Fully Qualified Domain Name Names
   (FQDN).  This identifier, retrieved using  Those identifiers are advertised in a new Router
   Advertisement (RA) option, is option and, when present, are associated with the
   set of information included within the RA and may later be used to RA.

   Based on this FQDN, hosts can retrieve additional information associated with the PvD by way of about
   their network access characteristics via an HTTP-
   over-TLS request. HTTP over TLS query.
   This allows applications to select which Provisioning Domains to use
   as well as to provide configuration parameters to the transport layer
   and above.

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 3, August 13, 2018.

Copyright Notice

   Copyright (c) 2017 2018 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Provisioning Domain Identification using Router
       Advertisements  . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  PvD ID Option for Router Advertisements . . . . . . . . .   4
     3.2.  Router Behavior . . . . . . . . . . . . . . . . . . . . .   5   7
     3.3.  Host Behavior . . . . . . . . . . . . . . . . . . . . . .   5   7
       3.3.1.  DHCPv6 configuration association  . . . . . . . . . .   6   8
       3.3.2.  DHCPv4 configuration association  . . . . . . . . . .   7   8
       3.3.3.  Interconnection Sharing by the Host . . . . . . . . .   7   9
   4.  Provisioning Domain Additional Information  . . . . . . . . .   7   9
     4.1.  Retrieving the PvD Additional Information . . . . . . . .   7   9
     4.2.  Operational Consideration to Providing the PvD Additional
           Information . . . . . . . .   9
     4.3.  PvD Additional Information Format . . . . . . . . . . . .   9
       4.3.1.  Connectivity Characteristics . . .  10
     4.3.  PvD Additional Information Format . . . . . .  10
       4.3.2. . . . . . .  11
       4.3.1.  Private Extensions  . . . . . . . . . . . . . . . . .  11
       4.3.3.  12
       4.3.2.  Example . . . . . . . . . . . . . . . . . . . . . . .  11  12
     4.4.  Detecting misconfiguration and misuse . . . . . . . . . .  12  13
   5.  Security  Operation Considerations  . . . . . . . . . . . . . . . . . . .  12  13
   6.  Privacy  Security Considerations . . . . . . . . . . . . . . . . . . .  12  15
   7.  IANA  Privacy Considerations  . . . . . . . . . . . . . . . . . . . . .  13  15
   8.  Acknowledgements  .  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13  16
   9.  Contributor . . .  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14  16
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14  16
     10.1.  Normative references . . . . . . . . . . . . . . . . . .  14  16
     10.2.  Informative references . . . . . . . . . . . . . . . . .  15  17
   Appendix A.  Changelog  . . . . . . . . . . . . . . . . . . . . .  16  19
     A.1.  Version 00  . . . . . . . . . . . . . . . . . . . . . . .  16  19
     A.2.  Version 01  . . . . . . . . . . . . . . . . . . . . . . .  16  19
     A.3.  Version 02  . . . . . . . . . . . . . . . . . . . . . . .  17  20
     A.4.  WG Document version 00  . . . . . . . . . . . . . . . . .  18

   Appendix B.  Connection monetary cost . . . . . . . . . . . . . .  18
     B.1.  Conditions  . . . . . . . . . . . . . .  20
     A.5.  WG Document version 01  . . . . . . . . .  18
     B.2.  Price . . . . . . . . . . . . . . . . . . . . . . . . . .  19
     B.3.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  20
   Authors' Addresses  21
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21

1.  Introduction

   It has become very common in modern networks for hosts to access the
   network
   internet through different network interfaces, tunnels, or next-hop
   routers.  To describe the set of network configurations associated
   with %% each access method, the concept of Provisioning Domain (PvD) was
   defined in [RFC7556].

   This specification provides document specifies a way to identify explicit PvDs with Fully Qualified
   Domain Names (FQDN).  The FQDN is thus (FQDN), called PvD ID
   in this document.  The PvD IDs is included IDs.  Those identifiers are
   advertised in a new Router Advertisement (RA) [RFC4861] option.  This new option, option called
   the PvD ID Router Advertisement option which, when present,
   associates the set
   of configurations with the PvD ID with all the information present in the same Router
   Advertisement as well as any configuration object, such as addresses,
   deriving from it.  The PVD ID Router Advertisement option may also
   contain a set of other RA message.  It is
   worth noting options.  Since such options are only
   considered by hosts implementing this specification, network
   operators may configure hosts that are 'PvD-aware' with PvDs that are
   ignored by other hosts.

   Since PvD IDs are used to identify different ways to access the
   internet, multiple PvDs (with different PvD IDs) could be provisioned
   on any a single host interface, as well as noting that interface.  Similarly, the same PvD ID could be used
   on different interfaces of a host in order to inform the
   host that all those PvDs with the same PvD ID, on different interfaces,
   ultimately provide identical services.

   This document also introduces a way for hosts to retrieve additional
   information related to a specific PvD by the mean means of an HTTP-over-TLS HTTP over TLS
   query using an URI derived from the PvD ID.  The retrieved JSON
   object contains additional network information that would typically be
   considered unfit, or too large, to be directly included in the Router Advertisements.  This information can
   Advertisement, but might be used by the
   networking stack, considered useful to the applications, or
   even sometimes users, when choosing which PvD and transport should be partially displayed to
   the users (e.g., by displaying a localized network service name).
   used.

2.  Terminology

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

   In addition, this document uses the following terminology:

   PvD:   A

   Provisioning Domain, a Domain (PvD):   A set of network configuration
      information; for more information, see [RFC7556].

   PvD ID:   A Fully Qualified Domain Name (FQDN) used to identify a
      PvD.

   Explicit PvD:   A PvD uniquely identified with a PvD ID. for  For more
      information, see [RFC7556].

   Implicit PvD:   A PvD associated with a set of configuration
      information that, in the absence of a PvD ID, is associated with identified
      by the host interface to which it is attached and the address of
      the advertising router.

3.  Provisioning Domain Identification using Router Advertisements

   Each provisioning domain is

   Explicit PvDs are identified by a PvD ID.  The PvD ID is a Fully
   Qualified Domain Name (FQDN) which MUST belong to the network
   operator in order to avoid ambiguity. naming collisions.  The same PvD ID MAY be
   used in several access networks when the set of configuration information is they ultimately provide
   identical (e.g. services (e.g., in all home networks subscribed to the same
   service).

3.1.  PvD ID Option for Router Advertisements

   This document introduces a Router Advertisement (RA) option called
   the
   PvD ID Router Advertisement Option, option.  It is used to convey the FQDN
   identifying a given PvD. PvD (see Figure 1), bind the PvD ID with
   configuration information received over DHCPv4 (see Section 3.3.2),
   enable the use of HTTP over TLS to retrieve the PvD Additional
   Information JSON object (see Section 4), as well as contain any other
   RA options which would otherwise be valid in the RA.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |H|L|     |H|L|A|        Reserved         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Sequence Number         |                             ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                             ...
   ...                         PvD ID FQDN                       ...
   ...             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ...             |                  Padding                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                             ...
   ...            Router Advertisement message header            ...
   ...             (Only present when A-flag is set)             ...
   ...                                                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Options ...
   +-+-+-+-+-+-+-+-+-+-+-+-

           Figure 1: PvD ID Router Advertisements Option format

   Type        :   (8 bits) To be defined by IANA.  Current
      experimentation uses the value of 253. 254.

   Length      :   (8 bits) The length of the option (including the Type
      and Length fields) in units of 8 octets.
      octets, including the Type and Length fields, the Router
      Advertisement message header, if any, as well as the RA options
      that are included within the PvD ID Option.

   H-flag      :   (1 bit) Whether 'HTTP' flag stating whether some PvD
      Additional Information is made available through HTTP over TLS, as
      described in Section 4.

   L-flag      :   (1 bit) Whether 'Legacy' flag stating whether the router is
      also providing IPv4 information using DHCPv4 (see Section 3.3.2).

   A-flag      :   (1 bit) 'Advertisement' flag stating whether the PvD
      ID Option is followed (right after padding to the next 64 bits
      boundary) by a Router Advertisement message header (See section
      4.2 of target="RFC4861"/>).

   Reserved    :   (14   (13 bits) Reserved for later use.  It MUST be set to
      zero by the sender and ignored by the receiver.

   Sequence    : Number:   (16 bits) Sequence number for the PvD Additional
      Information, as described in Section 4.

   PvD ID FQDN :   The FQDN used as PvD ID encoded in DNS format, as
      described in Section 3.1 of RFC1035 [RFC1035].  Note that for simple decoding,
      the domain  Domain names MUST NOT be encoded in the compressed form compression
      described in Section 4.1.4 of RFC1035 [RFC1035].  This encoding is
      the same as the one used in RFC8106 [RFC8106].  The encoding [RFC1035] MUST
      end with a null (zero-length) label. NOT be used.

   Padding     :   Zero or more padding octets such as to the next 8 octets
      boundary.  It MUST be set to zero by the option
      length (Type sender, and Length fields included) to eight times ignored by
      the value
      of receiver.

   RA message header :   (16 octets) When the Length field.  It A-flag is set, a full
      Router Advertisement message header as specified in [RFC4861].
      The 'Type', 'Code' and 'Checksum' fields (i.e. the first 32 bits),
      MUST be set to zero by the sender and ignored by the receiver.

   Routers MUST NOT include
      The other fields are to be set and parsed as specified in
      [RFC4861] or any updating documents.

   Options :   Zero or more than one PvD ID RA options that would otherwise be valid as
      part of the Router Advertisement
   Option in each RA.  In case multiple PvD ID options main body, but are found instead
      included in a
   given RA, hosts MUST ignore all but the first PvD ID option. Option such as to be ignored by hosts that
      are not 'PvD-aware'.

   Here is an example of a PvD ID option with example.org as the PvD ID
   FQDN and including a RDNSS and prefix information options:

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +---------------+-----------------------------------------------+
     | Type: 254     |  Length: 12   |0|0|0|        Reserved         |
     +---------------+-------------------------------+---------------+
     |       Sequence Number         |      7        |       e       |
     +---------------+-----------------------------------------------+
     |      m        |       a       |      m        |       p       |
     +---------------------------------------------------------------+
     |      l        |       e       |      3        |       o       |
     +---------------------------------------------------------------+
     |      r        |       g       |      0        |   0 (padding) |
     +---------------------------------------------------------------+
     |   0 (padding) |  0 (padding)  |   0 (padding) |   0 (padding) |
     +---------------+---------------+---------------+---------------+
     |  RDNSS option (RFC 6106) length: 5                          ...
     ...                                                           ...
     ...                                                             |
     +---------------------------------------------------------------+
     | Prefix Information Option (RFC 4861) length: 4              ...
     ...                                                             |
     ...                                                             |
     +---------------------------------------------------------------+

3.2.  Router Behavior

   A router MAY insert only send RAs containing at most one PvD ID Option RA option, but
   MUST NOT include more than one PvD ID RA option in an each RA.  In
   particular, the PvD ID RA option MUST NOT contain further PvD ID RA
   options.

   The included PvD ID is associated with all the other Option MAY contain zero, one, or more RA options included in which
   would otherwise be valid as part of the same
   RA (for example, and not limited to: Prefix Information [RFC4861],
   Recursive DNS Server [RFC8106], Routing Information [RFC4191]
   options). RA.  Such options are
   processed by PvD-aware hosts, while ignored by others.

   In order to provide multiple independent different PvDs, a router MUST send
   multiple RAs.  Different explicit PvDs MAY be advertised with RAs
   using different the same IPv6 source link-local addresses (LLA) (as
   proposed in [I-D.bowbakova-rtgwg-enterprise-pa-multihoming]), each of
   which MAY include address; but different implicit PvDs,
   advertised with different RAs, MUST use different link local
   addresses.

   Whenever an RA, for a single PvD, would need to be sent via multiple
   packets, the PvD ID option.  In such cases, routers MAY
   originate the different RAs using RA option header (i.e., all fields except the same datalink layer address.

   If
   'Options' field) MUST be repeated in all the router is actually a VRRP instance [RFC5798], then transmitted RAs.  But
   the
   procedure is identical except that options within the virtual datalink layer address
   is used as well as 'Options' field, MAY be transmitted only once,
   included in one of the virtual IPv6 LLA. transmitted PvD ID RA options.

3.3.  Host Behavior

   Hosts MUST associate received RAs provide and included configuration
   information for IPv6 hosts.  When a (e.g., Router Valid Lifetime, Prefix Information
   [RFC4861], Recursive DNS Server [RFC8106], Routing Information
   [RFC4191] options) with the explicit PvD identified by the first PvD
   ID Option present in the received RA, if any, or with the implicit
   PvD identified by the host
   receives an interface and the source address of the
   received RA message including otherwise.

   In case multiple PvD ID options are found in a given RA, hosts MUST
   ignore all but the first PvD ID Option, it option.

   Similarly, hosts MUST associate all the network configuration objects
   (e.g., default routers, addresses, more specific routes, DNS
   Recursive Resolvers) with the PvD associated with the RA which are last
   updated by the object.  For example, addresses that are generated using
   a received RA
   (the same types as in Section 3.3) Prefix Information option (PIO) are associated with the
   PvD identified by of the last received RA which included the given PIO.

   PvD
   ID Option, even if some objects are already associated with a
   different explicit or implicit PvD.  PvD ID are IDs MUST be compared in a case-
   insensitive case-insensitive manner (i.e., A=a),
   assuming ASCII with zero parity.
   Non-alphabetic parity while non-alphabetic codes must match
   exactly (see also Section 3.1 of [RFC1035]).

   If  For example,
   pvd.example.com or PvD.Example.coM would refer to the received RA does not include a PvD ID Option, same PvD.

   While resolving names, executing the host MUST
   associate default address selection
   algorithm [RFC6724] or executing the configuration objects which are updated by the received
   RA with an implicit PvD, even if some objects were already associated
   with a different explicit or implicit PvD.  This implicit PvD MUST be
   identified by the LLA of the router sending the RA and the interface
   on which the RA was received.

   This document does not update the way Router Advertisement options
   are processed.  But in addition to the option processing defined in
   other documents, hosts implementing this specification MUST associate
   each created or updated object (e.g. address, default route, more
   specific route, DNS server list) with the PvD associated with the
   received RA.

   While resolving names, executing the default address selection
   algorithm [RFC6724] or executing the default router selection
   algorithm ([RFC2461], [RFC4191] and [RFC8028]), hosts MAY consider
   only default router selection
   algorithm ([RFC2461], [RFC4191] and [RFC8028]), hosts MAY consider
   only the configuration associated with an arbitrary set of PvDs.

   For example, a host MAY associate a given process with a specific
   PvD, or a specific set of PvDs, while associating another process
   with another PvD.  A PvD-aware application might also be able to
   select, on a per-connection basis, which PvDs should be used for a
   given connection. used.  In
   particular, constrained devices such as small battery operated
   devices (e.g.  IoT), or devices with limited CPU or memory resources
   may purposefully use a single PvD while ignoring some received RAs
   containing different PvD IDs.

   The way an application expresses its desire to use a given PvD, or a
   set of PvDs, or the way this selection is enforced, is out of the
   scope of this document.  Useful insights about these considerations
   can be found in [I-D.kline-mif-mpvd-api-reqs].

3.3.1.  DHCPv6 configuration association

   When a host retrieves configuration elements using DHCPv6, DHCPv6 (e.g.,
   addresses or DNS recursive resolvers), they MUST be associated with
   the explicit or implicit PvD of the RA received on the same
   interface, sent from the same LLA, and with the O-flag or M-flag set
   [RFC4861].  If no such PvD is found, or whenever multiple different
   PvDs are found, the host behavior is unspecified.

   This process requires hosts to keep track of received RAs, associated
   PvD IDs, and routers LLA; it also assumes that the router either acts
   as a DHCPv6 server or relay and uses the same LLA for DHCPv6 and RA
   traffic (which may not be the case when the router uses VRRP to send
   its RA).

3.3.2.  DHCPv4 configuration association

   When a host retrieves configuration elements from DHCPv4, they MUST
   be associated with the explicit PvD received on the same interface,
   whose PVD ID Options L-flag is set and, in the case of a non point-
   to-point link, using the same datalink address.  If no such PvD is
   found, or whenever multiple different PvDs are found, the
   configuration elements coming from DHCPv4 MUST be associated with an
   IPv4-only the
   implicit PvD identified by the interface on which the DHCPv4
   transaction happened.  The case of multiple explicit PvD for an IPv4
   interface is undefined.

3.3.3.  Interconnection Sharing by the Host

   The situation when a node receives an RA on one interface (e.g.
   cellular) and shares this connectivity by also acting as a router by
   transmitting RA on another interface (e.g.  WiFi) is known as
   'tethering'.  It can be done as ND proxy.  The exact behavior is TBD
   but it is expected that the one or several PvD associated to the
   shared interface (e.g. cellular) will also be advertised to the
   clients on the other interface (e.g.  WiFi).

4.  Provisioning Domain Additional Information

   Once a new PvD ID is discovered, it may be used to retrieve
   additional

   Additional information about the network characteristics of can be
   retrieved based on the provided
   connectivity. PvD ID.  This set of information is called PvD
   Additional Information, and is encoded as a JSON object [RFC7159].

   The purpose of this additional set of information is to securely
   provide additional information to hosts applications about the connectivity
   that is provided using a given interface and source address pair.  It
   typically includes data that would be considered too large, or not
   critical enough, to be provided within an RA option.  The information
   contained in this object MAY be used by the operating system, network
   libraries, applications, or users, in order to decide which set of
   PvDs should be used for which connection, as described in
   Section 3.3.

4.1.  Retrieving the PvD Additional Information

   When the H-flag of the PvD ID Option is set, hosts MAY attempt to
   retrieve the PvD Additional Information associated with a given PvD
   by performing an HTTP over TLS [RFC2818] GET query to https://<PvD-
   ID>/.well-known/pvd [RFC5785].  Inversely, hosts MUST NOT do so
   whenever the H-flag is not set.

   Note that the DNS name resolution of <PvD-ID> the PvD ID, the PKI checks as
   well as the actual query MUST be performed using the PvD associated with the PvD ID. considered PvD.
   In other words, the name resolution, PKI checks, source address
   selection, as well as the next-hop router selection MUST be performed
   while using exclusively the set of configuration information attached
   with the PvD, as defined in Section 3.3.  In some cases, it may
   therefore be necessary to wait for an address to be available for use
   (e.g., once the Duplicate Address Detection or DHCPv6 processes are
   complete) before initiating the HTTP over TLS query.  If the PvD
   allows for temporary address per [RFC4941], then host hosts SHOULD use a
   temporary address to fetch the PvD Additional Information and SHOULD
   deprecate the used temporary address and generate a new temporary address.
   address afterward.

   If the HTTP status of the answer is greater than or equal to 400 the
   host MUST abandon and consider that there is no additional PvD
   information.  If the HTTP status of the answer is between 300 and
   399, inclusive, it MUST follow the redirection(s).  If the HTTP
   status of the answer is between 200 and 299, inclusive, the host MAY
   get a file containing a single JSON object.  When a JSON object could
   not be retrieved, an error message SHOULD be logged and/or displayed
   in a rate-limited fashion.

   After retrieval of the PvD Additional Information, hosts MUST watch keep
   track of the PvD ID Sequence field for change. Number value received in subsequent RAs
   including the same PvD ID.  In case a different the new value is greater than the one in
   value that was observed when the RA Sequence field is observed, PvD Additional Information object
   was retrieved (using serial number arithmetic comparisons [RFC1982]),
   or whenever the validity time included in the PVD Additional
   Information JSON object is expired, hosts MUST either perform a new
   query and retrieve a new version of the object, or, failing that,
   deprecate the object and stop using it. the additional information
   provided in the JSON object.

   Hosts retrieving a new PvD Additional Information object MUST check
   for the presence and validity of the mandatory fields specified in
   Section 4.3.  A retrieved object including an outdated expiration time that is
   already past or missing a mandatory element MUST be ignored.  In
   order to avoid traffic spikes synchronized queries toward the server hosting the PvD
   Additional Information when an object expires, a host which last
   retrieved an object at a time A, including a validity time B, SHOULD
   renew the object at a uniformly random time in the interval
   [(B-A)/2,A].

   The PvD Additional Information object includes a set of IPv6 prefixes
   (under the key "prefixes") which MUST be checked against all the
   Prefix Information Options advertised in the RA.  If any of the
   prefixes included in the PIO is not covered by at least one of the
   listed prefixes, the PvD associated with the tested prefix MUST be
   considered unsafe and MUST NOT be used.  While this does not prevent
   a malicious network provider, it does complicate some attack
   scenarios, and may help detecting misconfiguration.

   The server providing

4.2.  Operational Consideration to Providing the JSON files SHOULD also check whether PvD Additional
      Information

   Whenever the
   client address H-flag is part of the prefixes listed into set in the additional
   information and SHOULD return a 403 response code if there is no
   match.  The server MAY also use the client address to select the
   right JSON object to be returned.

4.2.  Providing the PvD Additional Information

   Whenever the H-flag is set in the PvD RA Option, PvD RA Option, a valid PvD
   Additional Information object MUST be made available to all hosts
   receiving the RA by the network operator.  In particular, when a
   captive portal is present, hosts MUST still be allowed to access perform
   DNS, PKI and HTTP over TLS operations related to the retrieval of the
   object, even before logging into the captive portal.

   Routers MAY increment the PVD ID Sequence number in order to inform
   host that a new PvD Additional Information object is available and
   should be retrieved.

   The server providing the JSON files SHOULD also check whether the
   client address is part of the prefixes listed into the additional
   information and SHOULD return a 403 response code if there is no
   match.

4.3.  PvD Additional Information Format

   The PvD Additional Information is a JSON object.

   The following array table presents the mandatory keys which MUST be
   included in the object:

   +----------+-----------------+-------------+------------------------+
   | JSON key | Description     | Type        | Example                |
   +----------+-----------------+-------------+------------------------+
   | name     | Human-readable  | UTF-8       | "Awesome Wifi"         |
   |          | service name    | string      |                        |
   |          |                 | [RFC3629]   |                        |
   | expires  | Date after      | [RFC3339]   | "2017-07-23T06:00:00Z" |
   |          | which this      |             |                        |
   |          | object is not   |             |                        |
   |          | valid           |             |                        |
   | prefixes | Array of IPv6   | Array of    | ["2001:db8:1::/48",    |
   |          | prefixes valid  | strings     | "2001:db8:4::/48"]     |
   |          | for this PVD    |             |                        |
   +----------+-----------------+-------------+------------------------+

   A retrieved object which does not include a valid string associated
   with the "name" key at the root of the object, or a valid date
   associated with the "expires" key, also at the root of the object,
   MUST be ignored.  In such cases, an error message SHOULD be logged
   and/or displayed in a rate-limited fashion.  If the PIO of the
   received RA is not included in covered by at least one of the "prefixes" key, the
   retrieved object SHOULD be ignored.

   The following table presents some optional keys which MAY be included
   in the object.

   +-----------------+-----------------+---------+---------------------+

   +---------------+-----------------+---------+-----------------------+
   | JSON key      | Description     | Type    | Example               |
   +-----------------+-----------------+---------+---------------------+
   +---------------+-----------------+---------+-----------------------+
   | localizedName | Localized user- | UTF-8   | "Wifi Genial"         |
   |               | visible service | string  |                       |
   |               | name, language  |         |                       |
   |               | can be selected |         |                       |
   |               | based on the    |         |                       |
   |               | HTTP Accept-    |         |                       |
   |               | Language header |         |                       |
   |               | in the request. |         |                       |
   | dnsZones      | DNS zones       | array   | ["example.com","sub ["example.com","sub.e |
   |               | searchable and  | of DNS  | .example.org"] xample.org"]          |
   |               | accessible      | zones   |                       |
   | noInternet    | No Internet,    | boolean | true                  |
   |               | set when the    |         |                       |
   |               | PvD only        |         |                       |
   |               | provides        |         |                       |
   |               | restricted      |         |                       |
   |               | access to a set |         |                       |
   |               | of services     |         |                       |
   | characteristics | Connectivity    | JSON    | See Section 4.3.1   |
   |                 | characteristics | object  |                     |
   | metered         | metered, when   | boolean | false               |
   |                 | the access      |         |                     |
   |                 | volume is       |         |                     |
   |                 | limited         |         |                     |
   +-----------------+-----------------+---------+---------------------+
   +---------------+-----------------+---------+-----------------------+

   It is worth noting that the JSON format allows for extensions.
   Whenever an unknown key is encountered, it MUST be ignored along with
   its associated elements.

4.3.1.  Connectivity Characteristics Information

   The following set of keys can be used to signal certain
   characteristics of the connection towards the PvD.

   They should reflect characteristics of the overall access technology
   which is not limited to the link the host is connected to, but rather
   a combination of the link technology, CPE upstream connectivity, and
   further quality of service considerations.

   +---------------+--------------+---------------------+--------------+
   | JSON key      | Description  | Type                | Example      |
   +---------------+--------------+---------------------+--------------+
   | maxThroughput | Maximum      | object({down(int),  | {"down":     |
   |               | achievable   | up(int)}) in kbit/s | 10000, "up": |
   |               | throughput   |                     | 5000}        |
   | minLatency    | Minimum      | object({down(int),  | {"down": 10, |
   |               | achievable   | up(int)}) in msec   | "up": 20}    |
   |               | latency      |                     |              |
   | rl            | Maximum      | object({down(int),  | {"down":     |
   |               | achievable   | up(int)}) in losses | 0.1, "up":   |
   |               | reliability  | every 1000 packets  | 1}           |
   +---------------+--------------+---------------------+--------------+

4.3.2.  Private Extensions

   JSON keys starting with "x-" are reserved for private use and can be
   utilized to provide information that is specific to vendor, user or
   enterprise.  It is RECOMMENDED to use one of the patterns "x-FQDN-
   KEY" or "x-PEN-KEY" where FQDN is a fully qualified domain name or
   PEN is a private enterprise number [PEN] under control of the author
   of the extension to avoid collisions.

4.3.3.

4.3.2.  Example

   Here are two examples based on the keys defined in this section.

   {
     "name": "Foo Wireless",
     "localizedName": "Foo-France Wifi",
     "expires": "2017-07-23T06:00:00Z",
     "prefixes" : ["2001:db8:1::/48", "2001:db8:4::/48"],
     "characteristics": {
      "maxThroughput": { "down":200000, "up": 50000 },
      "minLatency": { "down": 0.1, "up": 1 }
     }
   }
   {
     "name": "Bar 4G",
     "localizedName": "Bar US 4G",
     "expires": "2017-07-23T06:00:00Z",
     "prefixes": ["2001:db8:1::/48", "2001:db8:4::/48"],
     "metered": true,
     "characteristics": {
       "maxThroughput": { "down":80000, "up": 20000 }
     }
   }

4.4.  Detecting misconfiguration and misuse

   Although some solutions such as IPsec or SEND [RFC3971] can be used
   in order to secure the IPv6 Neighbor Discovery Protocol, actual
   deployments largely rely on link layer or physical layer security
   mechanisms (e.g. 802.1x [IEEE8021X]) in conjunction with RA Guard
   [RFC6105].

   This specification does not improve the Neighbor Discovery Protocol
   security model, but extends the purely link-local configuration
   retrieval mechanisms with HTTP-over-TLS communications and some
   checks to detect misconfiguration and some misuses.

   When a host retrieves the PvD Additional Information, it MUST verify
   that the HTTPS TLS server certificate is valid and for the performed request
   (e.g., that the Subject Name is equal to the PvD ID expressed as an FQDN.
   FQDN).  This authentication creates a secure binding between the
   information provided by the trusted Router Advertisement, and the
   HTTPS server.  But this does not mean the Advertising Router and the
   PvD server belong to the same entity.

   When the "prefixes" key is included in the PvD Additional
   Information, then host

   Hosts MUST verify that all prefixes in the RA PIO are covered by a prefixes
   prefix from the PvD Additional Informaion. Information.  An adversarial router
   willing to fake the use of a given explicit PvD, without any access
   to the actual PvD Additional Information, would need to perform NAT66
   in order to circumvent this check.

   It is also RECOMMENDED that the HTTPS server checks the source
   addresses of incoming connections (see Section 4.1).  This checks check give
   reasonable assurance that neither NPTv6 [RFC6296] nor NAT66 was not were used
   and also restrict restricts the information to the valid network users.

5.  Security  Operation Considerations

   It must

   This section describes some use cases of PvD.  For sake of
   simplicity, the RA messages will not be noted that described in the Section 4.4 of this document only provides
   reasonable assurance against misconfiguration usual ASCII
   art but does not prevent an
   hostile network access provider to wrong information that could lead
   applications or hosts to select an hostile PvD.  Users should always
   apply caution when connecting to rather in an unknown network.

6.  Privacy Considerations

   When indented list.  For example, a host retrieves via HTTPS the additional information, all nodes
   on the path (including the HTTPS server) can detect RA message
   containing some options and a PvD ID option that also contains other
   options will be described as:

   o  RA Header: router lifetime = 6000

   o  Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64

   o  PvD ID header: length = 3+ 5 +4 , PvD ID FQDN = example.org,
      A-flag = 0 (actual length of the node header with padding 24 bytes = 3
      * 8 bytes)

      *  Recursive DNS Server: length = 5, addresses=
         [2001:db8:cafe::53, 2001:db8:f00d::53]

      *  Prefix Information Option: length = 4, prefix =
         2001:db8:f00d::/64

   It is
   active.

   As it can be expected that the HTTPS server is located in the same
   management domain as the client (usually, it for some years, networks will be within an
   enterprise network, WiFi hotspot, or Service Provider network), the
   network operator as usually other means have a mix of PvD-
   aware hosts and PvD-ignorant hosts.  If there is a need to also detect give
   specific information to PvD-aware hosts only, then it is recommended
   to send TWO RA messages: one for each class of hosts.  For example,
   here is the new active
   node (DHCP, Neighbor Discovery Protocol cache inspection or RA for PvD-ignorant hosts:

   o  RA Header: router lifetime = 6000 (PvD-ignorant hosts will use
      this router as a default router)

   o  Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64

   o  Recursive DNS
   request logging).  In Server Option: length = 3, addresses=
      [2001:db8:cafe::53]

   o  PvD ID header: length = 3+ 2, PvD ID FQDN = foo.example.org,
      A-flag = 1 (actual length of the header 24 bytes = 3 * 8 bytes)

      *  RA Header: router lifetime = 0 (PvD-aware hosts will not use
         this case, privacy router as a default router), implicit length = 2

   And here is a RA example for PvD-aware hosts:

   o  RA Header: router lifetime = 0 (PvD-ignorant hosts will not worsened by using
   PvD.

   It must also be noted that most operating systems implement use
      this router as a system
   to detect the presence default router)

   o  PvD ID header: length = 3+ 2 + 4 + 3, PvD ID FQDN = example.org,
      A-flag = 1 (actual length of the header 24 bytes = 3 * 8 bytes)

      *  RA Header: router lifetime = 1600 (PvD-aware hosts will use
         this router as a captive portal and also connect to a
   well-known web site over default router), implicit length = 2

      *  Prefix Information Option: length = 4, prefix =
         2001:db8:f00d::/64

      *  Recursive DNS Server Option: length = 3, addresses=
         [2001:db8:f00d::53]

   In the Internet, for example to
   http://captive.example.com/hotspot-detect.html.  This detection
   mechanism is exposing above example, PvD-ignorant hosts will only use the activity of first RA
   sent from their default router and using the detecting node not 2001:db8:cafe::/64
   prefix.  PvD-aware hosts will autonomously configure addresses from
   both PIOs, but will only
   within use the management domain but also source address in 2001:db8:f00d::/64
   to all nodes outside this
   domain on communicate past the path to first hop router since only the captive.example.com server.  As PvD router
   sending the second RA will be used as default router; similarly, they
   will use the DNS server 2001:db8:f00d::53 when communicating with
   this adress.

6.  Security Considerations

   Although some solutions such as IPsec or SeND [RFC3971] can
   also be used
   in order to detect captive portal, then secure the PvD actually
   preserves privacy.

   Finally, IPv6 Neighbor Discovery Protocol, actual
   deployments largely rely on link layer or physical layer security
   mechanisms (e.g. 802.1x [IEEE8021X]) in conjunction with RA Guard
   [RFC6105].

   This specification does not improve the fetching of additional information is an option and
   could be disabled by Neighbor Discovery Protocol
   security model, but extends the host.

7.  IANA Considerations

   IANA is asked to assign purely link-local trust relationship
   between the value TBD from host and the IPv6 Neighbor
   Discovery Option Formats registry for default routers with HTTP over TLS
   communications which servers are authenticated as rightful owners of
   the FQDN received within the trusted PvD ID Router Advertisement RA option.

   IANA is asked

   It must be noted that Section 4.4 of this document only provides
   reasonable assurance against misconfiguration but does not prevent an
   hostile network access provider to assign wrong information that could lead
   applications or hosts to select an hostile PvD.  Users should always
   apply caution when connecting to an unknown network.

7.  Privacy Considerations

   Retrieval of the value "pvd" from PvD Additional Information over HTTPS requires early
   communications between the Well-Known URIs
   registry.

   IANA is asked to create connecting host and maintain a new registry entitled
   "Additional Information PvD Keys" containing ASCII strings.  The
   initial content of server which may be
   located further than the first hop router.  Although this registry are given below; future assignements
   are server is
   likely to be made through Expert Review [BCP36].

8.  Acknowledgements

   Many thanks located within the same administrative domain as the
   default router, this property can't be ensured.  Therefore, hosts
   willing to M.  Stenberg retrieve the PvD Additional Information before using it
   without leaking identity information, SHOULD make use of an IPv6
   Privacy Address and S.  Barth for their earlier work:
   [I-D.stenberg-mif-mpvd-dns].

   Thanks also to Mikael Abrahamson, Ray Bellis, Lorenzo Colitti,
   Thierry Danis, Bob Hinden, Tatuya Jinmei, Erik Kline, Ted Lemon, Jen
   Lenkova, Mark Townsley, James Woodyatt for useful and interesting
   discussions.

   Finally, many thanks SHOULD NOT include any privacy sensitive data,
   such as User Agent header or HTTP cookie, while performing the HTTP
   over TLS query.

   From a privacy perspective, retrieving the PvD Additional Information
   is not different from establishing a first connexion to Thierry Danis for his implementation work
   ([github]), Tom Jones for his integration effort into a remote
   server, or even performing a single DNS lookup.  For example, most
   operating systems already perform early queries to well known web
   sites, such as http://captive.example.com/hotspot-detect.html, in
   order to detect the Neat
   project and Rigil Salim presence of a captive portal.

   There may be some cases where hosts, for his implementation work.

9.  Contributor

   Basile Bruneau was privacy reasons, should
   refrain from accessing servers that are located outside a co-author of certain
   network boundary.  In practice, this document while he was studying
   at could be implemented as a
   whitelist of 'trusted' FQDNs and/or IP prefixes that the Polytechnique Paris.

10.  References

10.1.  Normative references

   [I-D.bowbakova-rtgwg-enterprise-pa-multihoming]
              Baker, F., Bowers, C., and J. Linkova, "Enterprise
              Multihoming using Provider-Assigned Addresses without
              Network Prefix Translation: Requirements and Solution",
              draft-bowbakova-rtgwg-enterprise-pa-multihoming-01 (work
              in progress), October 2016.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

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

   [RFC2461]  Narten, T., Nordmark, E., and W. Simpson, "Neighbor communicate with.  In such scenarios, the host SHOULD
   check that the provided PvD ID, as well as the IP address that it
   resolves into, are part of the allowed whitelist.

8.  IANA Considerations

   IANA is asked to assign the value TBD from the IPv6 Neighbor
   Discovery Option Formats registry for IP Version 6 the PvD ID Router Advertisement
   option.

   IANA is asked to assign the value "pvd" from the Well-Known URIs
   registry.

   IANA is asked to create and maintain a new registry entitled
   "Additional Information PvD Keys" containing ASCII strings.  The
   initial content of this registry are given in Section 4.3; future
   assignments are to be made through Expert Review [BCP36].

   Finally, IANA is asked to create and maintain a new registry entitled
   "PvD ID Router Advertisement option Flags" reserving bit positions
   from 0 to 15 to be used in the PvD ID Router Advertisement option
   bitmask.  Bit position 0, 1 and 2 are reserved by this document (as
   specified in Figure 1).  Future assignments require a Standard Track
   RFC document.

9.  Acknowledgements

   Many thanks to M.  Stenberg and S.  Barth for their earlier work:
   [I-D.stenberg-mif-mpvd-dns], as well as to Basile Bruneau who was
   author of an early version of this document.

   Thanks also to Marcus Keane, Mikael Abrahamson, Ray Bellis, Lorenzo
   Colitti, Bob Hinden, Tatuya Jinmei, Erik Kline, Ted Lemon, Jen
   Lenkova, Mark Townsley and James Woodyatt for useful and interesting
   discussions.

   Finally, special thanks to Thierry Danis and Wenqin Shao for their
   valuable inputs and implementation efforts ([github]), Tom Jones for
   his integration effort into the NEAT project and Rigil Salim for his
   implementation work.

10.  References

10.1.  Normative references

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

   [RFC1982]  Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,
              DOI 10.17487/RFC1982, August 1996,
              <https://www.rfc-editor.org/info/rfc1982>.

   [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>.

   [RFC2461]  Narten, T., Nordmark, E., and W. Simpson, "Neighbor
              Discovery for IP Version 6 (IPv6)", RFC 2461,
              DOI 10.17487/RFC2461, December 1998,
              <https://www.rfc-editor.org/info/rfc2461>.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818,
              DOI 10.17487/RFC2818, May 2000,
              <https://www.rfc-editor.org/info/rfc2818>.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
              2003, <https://www.rfc-editor.org/info/rfc3629>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007,
              <https://www.rfc-editor.org/info/rfc4861>.

   [RFC7159]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
              2014, <https://www.rfc-editor.org/info/rfc7159>.

   [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>.

10.2.  Informative references

   [github]   Cisco, "IPv6-mPvD github repository",
              <https://github.com/IPv6-mPvD>.

   [I-D.kline-mif-mpvd-api-reqs]
              Kline, E., "Multiple Provisioning Domains API
              Requirements", draft-kline-mif-mpvd-api-reqs-00 (work in
              progress), November 2015.

   [I-D.stenberg-mif-mpvd-dns]
              Stenberg, M. and S. Barth, "Multiple Provisioning Domains
              using Domain Name System", draft-stenberg-mif-mpvd-dns-00
              (work in progress), October 2015.

   [IEEE8021X]
              IEEE, "IEEE Standards for Local and Metropolitan Area
              Networks: Port based Network Access Control, IEEE Std".

   [PEN]      IANA, "Private Enterprise Numbers",
              <https://www.iana.org/assignments/enterprise-numbers>.

   [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>.

   [RFC3971]  Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
              "SEcure Neighbor Discovery (SEND)", RFC 3971,
              DOI 10.17487/RFC3971, March 2005,
              <https://www.rfc-editor.org/info/rfc3971>.

   [RFC4191]  Draves, R. and D. Thaler, "Default Router Preferences and
              More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
              November 2005, <https://www.rfc-editor.org/info/rfc4191>.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
              <https://www.rfc-editor.org/info/rfc4941>.

   [RFC5785]  Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
              Uniform Resource Identifiers (URIs)", RFC 5785,
              DOI 10.17487/RFC5785, April 2010,
              <https://www.rfc-editor.org/info/rfc5785>.

   [RFC5798]  Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP)
              Version 3 for IPv4 and IPv6", RFC 5798,
              DOI 10.17487/RFC5798, March 2010,
              <https://www.rfc-editor.org/info/rfc5798>.

   [RFC6105]  Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J.
              Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105,
              DOI 10.17487/RFC6105, February 2011,
              <https://www.rfc-editor.org/info/rfc6105>.

   [RFC6296]  Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix
              Translation", RFC 6296, DOI 10.17487/RFC6296, June 2011,
              <https://www.rfc-editor.org/info/rfc6296>.

   [RFC6724]  Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
              "Default Address Selection for Internet Protocol Version 6
              (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
              <https://www.rfc-editor.org/info/rfc6724>.

   [RFC7556]  Anipko, D., Ed., "Multiple Provisioning Domain
              Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015,
              <https://www.rfc-editor.org/info/rfc7556>.

   [RFC8028]  Baker, F. and B. Carpenter, "First-Hop Router Selection by
              Hosts in a Multi-Prefix Network", RFC 8028,
              DOI 10.17487/RFC8028, November 2016,
              <https://www.rfc-editor.org/info/rfc8028>.

   [RFC8106]  Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
              "IPv6 Router Advertisement Options for DNS Configuration",
              RFC 8106, DOI 10.17487/RFC8106, March 2017,
              <https://www.rfc-editor.org/info/rfc8106>.

Appendix A.  Changelog

   Note to RFC Editors: Remove this section before publication.

A.1.  Version 00

   Initial version of the draft.  Edited by Basile Bruneau + Eric Vyncke
   and based on Basile's work.

A.2.  Version 01

   Major rewrite intended to focus on the the retained solution based on
   corridors, online, and WG discussions.  Edited by Pierre Pfister.
   The following list only includes major changes.

      PvD ID is an FQDN retrieved using a single RA option.  This option
      contains a sequence number for push-based updates, a new H-flag,
      and a L-flag in order to link the PvD with the IPv4 DHCP server.

      A lifetime is included in the PvD ID option.

      Detailed Hosts and Routers specifications.

      Additional Information is retrieved using HTTP-over-TLS when the
      PvD ID Option H-flag is set.  Retrieving the object is optional.

      The PvD Additional Information object includes a validity date.

      DNS-based approach is removed as well as the DNS-based encoding of
      the PvD Additional Information.

      Major cut in the list of proposed JSON keys.  This document may be
      extended later if need be.

      Monetary discussion is moved to the appendix.

      Clarification about the 'prefixes' contained in the additional
      information.

      Clarification about the processing of DHCPv6.

A.3.  Version 02

      The FQDN is now encoded with ASCII format (instead of DNS binary)
      in the RA option.

      The PvD ID option lifetime is removed from the object.

      Use well known URI "https://<PvD-ID>/.well-known/pvd"

      Reference RFC3339 for JSON timestamp format.

      The PvD ID Sequence field has been extended to 16 bits.

      Modified host behavior for DHCPv4 and DHCPv6.

      Removed IKEv2 section.

      Removed mention of RFC7710 Captive Portal option.  A new I.D.
      will be proposed to address the captive portal use case.

A.4.  WG Document version 00

      Document has been accepted as INTAREA working group document

      IANA considerations follow RFC8126 [RFC8126]

      PvD ID FQDN is encoded as per RFC 1035 [RFC1035]

      PvD ID FQDN is prepended by a one-byte length field

      Marcus Keane added as co-author

      dnsZones key is added back

      draft of a privacy consideration section and added that a
      temporary address should be used to retrieve the PvD additional
      information

      per Bob Hinden's request: the document is now aiming at standard
      track and security considerations have been moved to the main
      section

Appendix B.  Connection monetary cost

   NOTE: This section is included as a request for comment on the
   potential use and syntax.

   The billing of a connection can be done in a lot of different ways.
   The user can have a global traffic threshold per month, after which
   his throughput is limited, or after which he/she pays each megabyte.
   He/she can also have an unlimited access to some websites, or an
   unlimited access during the weekends.

   An option is to split the bill in elementary billings, which have
   conditions (a start date, an end date, a destination IP address...).
   The global billing is an ordered list of elementary billings.  To
   know the cost of a transmission, the host goes through the list, and
   the first elementary billing whose the conditions are fulfilled gives
   the cost.  If no elementary billing conditions match the request, the
   host MUST make no assumption about the cost.

B.1.  Conditions

   Here are the potential conditions for an elementary billing.  All
   conditions MUST be fulfill.

   +-----------+-------------+---------------+-------------------------+
   | Key       | Description | Type          | JSON Example            |
   +-----------+-------------+---------------+-------------------------+
   | beginDate | Date before | ISO 8601      | "1977-04-22T06:00:00Z"  |
   |           | which the   |               |                         |
   |           | billing is  |               |                         |
   |           | not valid   |               |                         |
   | endDate   | Date after  | ISO 8601      | "1977-04-22T06:00:00Z"  |
   |           | which the   |               |                         |
   |           | billing is  |               |                         |
   |           | not valid   |               |                         |
   | domains   | FQDNs whose | array(string) | ["deezer.com","spotify. |
   |           | the billing |               | com"]                   |
   |           | is limited  |               |                         |
   | prefixes4 | IPv4        | array(string) | ["78.40.123.182/32","78 |
   |           | prefixes    |               | .40.123.183/32"]        |
   |           | whose the   |               |                         |
   |           | billing is  |               |                         |
   |           | limited     |               |                         |
   | prefixes6 | IPv6        | array(string) | ["2a00:1450:4007:80e::2 |
   |           | prefixes    |               | 00e/64"]                |
   |           | whose the   |               |                         |
   |           | billing is  |               |                         |
   |           | limited     |               |                         |
   +-----------+-------------+---------------+-------------------------+

B.2.  Price

   Here are L-flag in order to link the different possibilities for PvD with the cost of an elementary
   billing. IPv4 DHCP server.

      A missing key means "all/unlimited/unrestricted".  If lifetime is included in the
   elementary billing selected has PvD ID option.

      Detailed Hosts and Routers specifications.

      Additional Information is retrieved using HTTP-over-TLS when the
      PvD ID Option H-flag is set.  Retrieving the object is optional.

      The PvD Additional Information object includes a trafficRemaining validity date.

      DNS-based approach is removed as well as the DNS-based encoding of 0 kb, then it
   means that
      the user has no access to PvD Additional Information.

      Major cut in the network.  Actually, list of proposed JSON keys.  This document may be
      extended later if need be.

      Monetary discussion is moved to the
   last elementary billing has a trafficRemaining parameter, it means
   that when appendix.

      Clarification about the user will reach 'prefixes' contained in the threshold, he/she will not have
   access to additional
      information.

      Clarification about the network anymore.

   +------------------+------------------+--------------+--------------+
   | Key              | Description      | Type         | processing of DHCPv6.

A.3.  Version 02

      The FQDN is now encoded with ASCII format (instead of DNS binary)
      in the RA option.

      The PvD ID option lifetime is removed from the object.

      Use well known URI "https://<PvD-ID>/.well-known/pvd"

      Reference RFC3339 for JSON Example |
   +------------------+------------------+--------------+--------------+
   | pricePerGb       | timestamp format.

      The price per    | float        | 2            |
   |                  | Gigabit          | (currency    |              |
   |                  |                  | PvD ID Sequence field has been extended to 16 bits.

      Modified host behavior for DHCPv4 and DHCPv6.

      Removed IKEv2 section.

      Removed mention of RFC7710 Captive Portal option.  A new I.D.
      will be proposed to address the captive portal use case.

A.4.  WG Document version 00

      Document has been accepted as INTAREA working group document

      IANA considerations follow RFC8126 [RFC8126]

      PvD ID FQDN is encoded as per Gb)      |              |
   | currency         | The currency     | ISO 4217     | "EUR"        |
   |                  | used             |              |              |
   | throughputMax    | The maximum      | float (kb/s) | 100000       |
   |                  | achievable       |              |              |
   |                  | throughput       |              |              |
   | trafficRemaining | The traffic      | float (kB)   | 12000000     |
   |                  | remaining        |              |              |
   +------------------+------------------+--------------+--------------+

B.3.  Examples

   Example for RFC 1035 [RFC1035]

      PvD ID FQDN is prepended by a user with 20 GB per month for 40 EUR, then reach one-byte length field

      Marcus Keane added as co-author

      dnsZones key is added back

      draft of a
   threshold, and with unlimited data during weekends privacy consideration section and added that a
      temporary address should be used to
   example.com:

   [
     {
       "domains": ["example.com"]
     },
     {
       "prefixes4": ["78.40.123.182/32","78.40.123.183/32"]
     },
     {
       "beginDate": "2016-07-16T00:00:00Z",
       "endDate": "2016-07-17T23:59:59Z",
     },
     {
       "beginDate": "2016-06-20T00:00:00Z",
       "endDate": "2016-07-19T23:59:59Z",
       "trafficRemaining": 12000000
     },
     {
       "throughputMax": 100000
     }
   ]

   If retrieve the host tries PvD additional
      information

      per Bob Hinden's request: the document is now aiming at standard
      track and security considerations have been moved to download data from example.com, the conditions main
      section

A.5.  WG Document version 01

      Removing references to 'metered' and 'characteristics' keys.
      Those may be in scope of the first elementary billing are fulfilled, so the host takes PvD work, but this
   elementary billing, finds no cost indication in it document will
      focus on essential parts only.

      Removing appendix section regarding link quality and so deduces billing
      information.

      The PvD RA Option may now contain other RA options such that it PvD-
      aware hosts may receive configuration information otherwise
      invisible to non-PvD-aware hosts.

      Clarify that the additional PvD Additional Information is totally free.  If not
      intended to modify host's networking stack behavior, but rather
      provide information to the host tries Application, used to exchange data with
   foobar.com select which PvDs
      must be used and provide configuration parameters to the date transport
      layer.

      The RA option padding is 2016-07-14T19:00:00Z, the conditions of
   the first, second and third elementary billing are not fulfilled.

   But used to increase the conditions of option size to the fourth are.  So
      next 64 (was 32) bits boundary.

      Better detail the host takes this
   elementary billing and sees that there is a threshold, 12 GB are
   remaining.

   Another example for a user abroad, who has 3 GB per year abroad, Security model and
   then pay each MB:

   [
     {
       "beginDate": "2016-02-10T00:00:00Z",
       "endDate": "2017-02-09T23:59:59Z",
       "trafficRemaining": 3000000
     },
     {
       "pricePerGb": 30,
       "currency": "EUR"
     }
   ] Privacy considerations.

Authors' Addresses

   Pierre Pfister
   Cisco
   11 Rue Camille Desmoulins
   Issy-les-Moulineaux  92130
   France

   Email: ppfister@cisco.com

   Eric Vyncke (editor)
   Cisco
   De Kleetlaan, 6
   Diegem  1831
   Belgium

   Email: evyncke@cisco.com

   Tommy Pauly
   Apple

   Email: tpauly@apple.com
   David Schinazi
   Apple

   Email: dschinazi@apple.com

   Marcus Keane
   Microsoft
   Sandyford Industrial Estate
   Dublin 18
   Ireland

   Email: Marcus.Keane@microsoft.com