Re: [Int-area] [v6ops] WG Adoption Call: Discovering Provisioning Domain Names and Data

[Bob Hinden <[e-mail]>]

Hi,

I read the document and have some comments.

Overall I think working on Provisioning Domains is fine in Int-Area, but I think the document has issues that need to be resolved.  I will leave it for the w.g. chairs to decide if they need to be fixed before or after adoption.

Specific comments below.  They range from serious to editorial.

Bob


> 
> intarea                                                  P. Pfister, Ed.
> Internet-Draft                                                     Cisco
> Intended status: Informational                               D. Schinazi

I don’t think this can Informational.  It defines an IPv6 RA option and requests IANA allocations.  It should be Standards Track.

> Expires: January 29, 2018                                       T. Pauly
>                                                                    Apple
>                                                                E. Vyncke
>                                                                    Cisco
>                                                               B. Bruneau
>                                                      Ecole Polytechnique
>                                                            July 28, 2017
> 
> 
>              Discovering Provisioning Domain Names and Data
>              draft-bruneau-intarea-provisioning-domains-02
> 
> Abstract
> 
>    An increasing number of hosts and networks are connected to the
>    Internet through multiple interfaces, some of which may provide
>    multiple ways to access the internet by the mean of 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 called a
>    Provisioning Domain (PvD) and is identified by a Fully Qualified
>    Domain Name (FQDN).  This identifier, retrieved using a new Router
>    Advertisement (RA) option, is associated with the set of information
>    included within the RA and may later be used to retrieve additional
>    information associated with the PvD by the mean of an HTTP request.
> 
> 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 http://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 January 29, 2018.
> 
> 
> 
> 
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> 
> Copyright Notice
> 
>    Copyright (c) 2017 IETF Trust and the persons identified as the
>    document authors.  All rights reserved.
> 
>    This document is subject to BCP 78 and the IETF Trust's Legal
>    Provisions Relating to IETF Documents
>    (http://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
>      3.3.  Host Behavior . . . . . . . . . . . . . . . . . . . . . .   5
>        3.3.1.  DHCPv6 configuration association  . . . . . . . . . .   6
>        3.3.2.  DHCPv4 configuration association  . . . . . . . . . .   7
>        3.3.3.  Interconnection Sharing by the Host . . . . . . . . .   7
>    4.  Provisioning Domain Additional Information  . . . . . . . . .   7
>      4.1.  Retrieving the PvD Additional Information . . . . . . . .   7
>      4.2.  Providing the PvD Additional Information  . . . . . . . .   9
>      4.3.  PvD Additional Information Format . . . . . . . . . . . .   9
>        4.3.1.  Connectivity Characteristics Information  . . . . . .  10
>        4.3.2.  Private Extensions  . . . . . . . . . . . . . . . . .  11
>        4.3.3.  Example . . . . . . . . . . . . . . . . . . . . . . .  11
>    5.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
>    6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  12
>    7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
>    8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
>    9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
>      9.1.  Normative references  . . . . . . . . . . . . . . . . . .  13
>      9.2.  Informative references  . . . . . . . . . . . . . . . . .  13
>    Appendix A.  Changelog  . . . . . . . . . . . . . . . . . . . . .  15
>      A.1.  Version 00  . . . . . . . . . . . . . . . . . . . . . . .  15
>      A.2.  Version 01  . . . . . . . . . . . . . . . . . . . . . . .  15
>      A.3.  Version 02  . . . . . . . . . . . . . . . . . . . . . . .  16
>    Appendix B.  Connection monetary cost . . . . . . . . . . . . . .  16
>      B.1.  Conditions  . . . . . . . . . . . . . . . . . . . . . . .  17
>      B.2.  Price . . . . . . . . . . . . . . . . . . . . . . . . . .  17
> 
> 
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>      B.3.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  18
>    Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19
> 
> 1.  Introduction
> 
>    It has become very common in modern networks that hosts have internet
>    or more specific network access through different networking
>    interfaces, tunnels, or next-hop routers.  The concept of
>    Provisioning Domain (PvD) was defined in [RFC7556] as a set of
>    network configuration information which can be used by hosts in order
>    to access the network.
> 
>    This specification provides a way to identify explicit PvDs with
>    Fully Qualified Domain Names called PvD IDs, which are included in a
>    new Router Advertisement [RFC4861] option.  This new option, when
>    present, is used to associate the correlated set of configuration
>    information with the identified PvD.  It is worth noting that
>    multiple PvDs with different PvD IDs could be provisioned on any host
>    interface, as well as noting that the same PvD ID could be used on
>    different interfaces in order to inform the host that both PvDs, 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 of an 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 be used by the
>    networking stack, the applications, or even be partially displayed to
>    the users (e.g., by displaying a localized network service name).

I object to this inclusion of using HTTP to obtain additional information.  More specific comments later, but will make the mechanism much less robust as it crosses many layers.  I suspect it will also create many security issues.


> 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 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 more
>       information, see [RFC7556].
> 
> 
> 
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> 
>    Implicit PvD:   A PvD associated with a set of configuration
>       information that, in the absence of a PvD ID, is associated with
>       the advertising router.
> 
> 3.  Provisioning Domain Identification using Router Advertisements
> 
>    Each provisioning domain is 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.  The same PvD ID MAY be used in
>    several access networks when the set of configuration information is
>    identical (e.g. in all home networks subscribed to the same service).
> 
> 3.1.  PvD ID Option for Router Advertisements
> 
>    This document introduces a new Router Advertisement (RA) option
>    called the PvD ID Router Advertisement Option, used to convey the
>    FQDN identifying a given PvD.
> 
>     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|         Reserved          |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |           Sequence            |                             ...
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+          PvD ID FQDN        ...
>    ...                                                           ...
>    ...             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    ...             |                  Padding                      |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> 
>                 PvD ID Router Advertisements Option format
> 
>    Type        :   (8 bits) To be defined by IANA.
> 
>    Length      :   (8 bits) The length of the option (including the Type
>       and Length fields) in units of 8 octets.
> 
>    H-flag      :   (1 bit) Whether some PvD Additional Information is
>       made available through HTTP over TLS, as described in Section 4.
> 
>    L-flag      :   (1 bit) Whether the router is also providing IPv4
>       access using DHCPv4 (see Section 3.3.2).

This is the first instance of an IPv6 extension including information about IPv4 I can remember.  I find this troublesome.  As far as I can tell, the IETF approach has been to keep the two protocols separate.  This builds in a dependency that will make turning off IPv4 difficult in the future.

Also, the text "router is also providing IPv4 access using DHCPv4” doesn’t parse well.  Router don’t provide IPv4 access by using DHCPv4.  DHCPv4 may be used to provide IPv4 addresses.  Not sure what this is intended to mean.

> 
>    Reserved    :   (14 bits) Reserved for later use.  It MUST be set to
>       zero by the sender and ignored by the receiver.
> 
>    Sequence    :   (16 bits) Sequence number for the PvD Additional
>       Information, as described in Section 4.


Is 16 bits long enough?  What is the expected frequency of using this, what happens if it wraps, etc.?  Has there been any analysis?

> 
> 
> 
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> 
>    PvD ID FQDN :   An ASCII string representation of the FQDN used as
>       PvD ID.  The string ends at the first byte set to zero, or the end
>       of the option, whichever comes first.

Is this a standard way of representing FQDNs?   Shouldn’t this reference Section 3.1 of [RFC1035].  Or is some other new representation being used?

> 
>    Padding     :   Zero or more padding octets such as to set the option
>       length (Type and Length fields included) to eight times the value
>       of the Length field.  It MUST be set to zero by the sender and
>       ignored by the receiver.
> 
>    Routers MUST NOT include more than one PvD ID Router Advertisement
>    Option in each RA.  In case multiple PvD ID options are found in a
>    given RA, hosts MUST ignore all but the first PvD ID option.
> 
>    Note: The existence and/or size of the sequence number is subject to
>    discussion.  The validity of a PvD Additional Information object is
>    included in the object itself, but this only allows for 'pull based'
>    updates, whereas the RA options usually provide 'push based' updates.
> 
> 3.2.  Router Behavior
> 
>    A router MAY insert at most one PvD ID Option in its RAs.  The

I think this should say “A router MAY insert only one PvD ID Option in a RA”.   I found the current text to not be clear.


>    included PvD ID is associated with all the other options included in
>    the same RA (e.g., Prefix Information [RFC4861], Recursive DNS Server
>    [RFC6106], Routing Information [RFC4191] options).
> 
>    In order to provide multiple independent PvDs, a router MUST send
>    multiple RAs using different source link-local addresses (LLA) (as
>    proposed in [I-D.bowbakova-rtgwg-enterprise-pa-multihoming]), each of

This is creating a normative reference dependency, but the document is listed as Informational.

>    which MAY include a PvD ID option.  In such cases, routers MAY
>    originate the different RAs using the same datalink layer address.
> 
>    If the router is actually a VRRP instance [RFC5798], then the
>    procedure is identical except that the virtual datalink layer address
>    is used as well as the virtual IPv6 addresses.
> 
> 3.3.  Host Behavior
> 
>    RAs are used to configure IPv6 hosts.  When a host receives an RA

That not quite right, RAs do not configure IPv6 hosts, they provide information to IPv6 hosts.

>    message including a PvD ID Option, it MUST associate all the
>    configuration objects which are updated by the received RA (e.g.,
>    Prefix Information [RFC4861], Recursive DNS Server [RFC6106], Routing
>    Information [RFC4191] options) with the PvD identified by the PvD ID
>    Option, even if some objects are already ssociated with a different
>    explicit or implicit PvD.

The correct reference is RFC8106, not RFC6101.  The title is "IPv6 Router Advertisement Options for DNS Configuration”

Are there any other RA options should should be considered?

> 
>    If the received RA does not include a PvD ID Option, the host MUST
>    associate the configuration objects which are updated by the received
>    RA with an implicit PvD, even if some objects were already associated
> 
> 
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> 
>    with a different explicit or implicit PvD.  This implicit PvD is
>    identified by the link-local address of the router sending the RA and
>    the interface on which the RA was received.

This text is saying that all current deployed IPv6 nodes much do this.  I think the text should be saying that nodes implementing this document should do this.  Hard to changed current devices :-(

> 
>    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.
> 
>    Note: There is a discussion whether there can be multiple implicit
>    PvDs on a single interface (i.e. whether the router link-local
>    address should be used to identify the implicit PvDs).
> 
>    While resolving names, executing the default address selection

Should a reference be added that says how to resolve names?

>    algorithm [RFC6724] or executing the 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.  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.

This seems somewhat vague.  Does it belong here?

> 
>    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, they MUST
>    be associated with the explicit or implicit PvD of the RA received on
>    the same interface, using the same link-local address, and with the
>    O-flag set [RFC4861].  If no such PvD is found, or whenever multiple
>    different PvDs are found, the host behavior is unspecified.

Perhaps something more specific should be describe in this case.

> 
>    This process requires hosts to keep track of received RAs, associated
>    PvD IDs, and routers link-local addresses.
> 
> 
> 
> 
> 
> 
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> 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 link-layer 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 implicit PvD identified by the interface on which the
>    DHCPv4 transaction happened.

Same comments above about including IPv4 information, and using IPv6 to manage IPv4.  I suggest removing it.

> 
> 3.3.3.  Interconnection Sharing by the Host
> 
>    The situation when a host becomes also a router by acting as a router
>    or ND proxy on a different interface (such as WiFi) to share the
>    connectivity of another interface (such as cellular), also known as
>    "tethering" is TBD but it is expected that the one or several PvD
>    associated to the shared interface will also be advertised to the
>    clients.

See Section 2 of RFC8200 and the Note at the end of the section.  A host doesn’t become a router….

> 
> 4.  Provisioning Domain Additional Information
> 
>    Once a new PvD ID is discovered, it may be used to retrieve
>    additional information about the characteristics of the provided
>    connectivity.  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 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.

I think creates all kinds of problem and security issues by having something that is learned in an RA initing getting configuration via HTTP.  Will this work if the RA processing is done in the kernel?

Is there really a problem including enough information in an RA?  Is there really going to be more than ~1300 bytes in the common case?  This mechanism is adding a lot of complexity to make this work.

Who decides what the <PvD-ID>/.well-known/pvd is, how does it get provisioned in a router?  What if a bad actor on the LAN sends it?   What happens if there isn’t access to the Internet at the time the RA is received?  Etc., etc.

> 
>    Note: Should the PvD AI retrieval be a MAY or a SHOULD ? Could the
>    object contain critical data, or should it only contain informational
>    data ?
> 
> 
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> 
>    Note that the DNS name resolution of <PvD-ID> as well as the actual
>    query MUST be performed using the PvD associated with the PvD ID.  In
>    other words, the name resolution, 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 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
>    included and 399 included it MUST follow the redirection(s).  If the
>    HTTP status of the answer is between 200 included and 299 included
>    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.

My initial impression when I read this was “WOW”.  Should this really be defining rules on how HTTP errors are processed?   Is there a reference to these error codes?  Are they standard, or common practice?

> 
>    After retrieval of the PvD Additional Information, hosts MUST watch
>    the PvD ID Sequence field for change.  In case a different value than
>    the one in the RA Sequence field is observed, 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 deprecate the object and stop using it.
> 
>    Hosts retrieving a new PvD Additional Information object MUST check
>    for the presence and validity of the mandatory fields Section 4.3.  A
>    retrieved object including an outdated expiration time or missing a
>    mandatory element MUST be ignored.  In order to avoid traffic spikes
>    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
>    which MUST be checked against all the Prefix Information Options
>    advertised in the Router Advertisement.  If any of the prefixes
>    included in the Prefix Information Options is not included in 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 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
> 
> 
> 
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> 
>    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, a valid PvD
>    Additional Information object MUST be made available to all hosts

Who or what does this “MUST” apply to?  I don’t understand what is intended.

>    receiving the RA.  In particular, when a captive portal is present,
>    hosts MUST still be allowed to access 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.
> 
> 4.3.  PvD Additional Information Format
> 
>    The PvD Additional Information is a JSON object.
> 
>    The following array 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    |                        |
>    | expires  | Date after which  | [RFC3339] | "2017-07-23T06:00:00Z" |
>    |          | 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      |           |                        |
>    +----------+-------------------+-----------+————————————+

Is the specification of this adequate?  What defines UTF-8?  Etc.

> 
>    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 "expiration" 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.
> 
>    The following table presents some optional keys which MAY be included
>    in the object.
> 
> 
> 
> 
> 
> 
> 
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> 
> 
>    +-----------------+-----------------------+---------+---------------+
>    | JSON key        | Description           | Type    | Example       |
>    +-----------------+-----------------------+---------+---------------+
>    | localizedName   | Localized user-       | UTF-8   | "Wifi Genial" |
>    |                 | visible service name, | string  |               |
>    |                 | language can be       |         |               |
>    |                 | selected based on the |         |               |
>    |                 | HTTP Accept-Language  |         |               |
>    |                 | header in the         |         |               |
>    |                 | request.              |         |               |
>    | noInternet      | No Internet, set when | boolean | true          |
>    |                 | the PvD only provides |         |               |
>    |                 | restricted access to  |         |               |
>    |                 | a set of services.    |         |               |
>    | characteristics | Connectivity          | JSON    | See Section   |
>    |                 | characteristics       | object  | 4.3.1         |
>    | metered         | metered, when the     | boolean | false         |
>    |                 | 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 kb/s   | 10000, "up": |
>    |               | throughput   |                     | 5000}        |
>    | minLatency    | Minimum      | object({down(int),  | {"down": 10, |
>    |               | achievable   | up(int)}) in ms     | "up": 20}    |
>    |               | latency      |                     |              |
>    | rl            | Maximum      | object({down(int),  | {"down":     |
>    |               | achievable   | up(int)}) in losses | 0.1, "up":   |
>    |               | reliability  | every 1000 packets  | 1}           |
>    +---------------+--------------+---------------------+--------------+
> 
> 

Are there any units associated with this?  For example, is it bps, KBps, MBps?  Time in seconds, days, years, msec?  What does “Max achievable reliability” even mean?




> 
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> 
> 
> 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.  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 }
>      }
>    }
> 
> 5.  Security Considerations
> 
>    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.
> 
> 
> 
> 
> 
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> 
>    During the exchange, the server authenticity is verified by the mean
>    of a certificate, validated based on the FQDN found in the Router
>    Advertisement (e.g. using a list of pre-installed CA certificates, or
>    DNSSec [RFC4035] with DNS Based Authentication of Named Entities
>    [RFC6698]).  This authentication creates a secure binding between the
>    information provided by the trusted Router Advertisement, and the
>    HTTP server.  But this does not mean the Advertising Router and the
>    PvD server belong to the same entity.

How is the certificate provisioned?  Who does it?  Who pre-installed them?  In an IoT device?

This needs to be fleshed out in the main part of the document.

> 
>    The IPv6 prefixes list included in the PvD Additional Information
>    JSON object is used to validate that the prefixes included in the
>    Router Advertisements are really part of the PvD.  An adversarial
>    router willing to fake the use of a given explicit PvD, without any
>    access to the actual PvD, would need to perform NAT66 in order to
>    circumvent this check.
> 
>    It is also RECOMMENDED that the PvD server checks the source
>    addresses of incoming connexions (see Section 4.1).  This check
>    ensures that the internet access provided by any router advertising a
>    given PvD eventually reaches the internet using the actual PvD
>    (Tunneling can still be used).
> 
>    For privacy reasons, it is desirable that the PvD Additional
>    Information object may only be retrieved by the hosts using the given
>    PvD.  Host identity SHOULD be validated based on the client address
>    that is used during the HTTP query.

The Security Considerations should be describing issues, not defining mechanisms.  The later should be in the document.  See: RFC3552 "Guidelines for Writing RFC Text on Security Considerations”.

> 
> 6.  Privacy Considerations
> 
>    TBD

> 7.  IANA Considerations
> 
>    IANA is kindly requested to allocate a new IPv6 Neighbor Discovery
>    option number for the PvD ID Router Advertisement option.
> 
>    The URI used to retrieve the PvD Additional Information JSON object
>    is the well known URI (see [RFC5785]) with the URI suffix "pvd".
> 
>    TBD: JSON keys will need a new registry.

This will have to be defined here.


> 
> 8.  Acknowledgements
> 
>    Many thanks to M. Stenberg and S. Barth for their earlier work:
>    [I-D.stenberg-mif-mpvd-dns].
> 
> 
> 
> 
> 
> 
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> 
> 
>    Thanks also to Ray Bellis, Lorenzo Colitti, Thierry Danis, Marcus
>    Keane, Erik Kline, Jen Lenkova, Mark Townsley, James Woodyatt and
>    Mikael Abrahamson for useful and interesting discussions.
> 
>    Finally, many thanks to Thierry Danis for his implementation work
>    ([github]), Tom Jones for his integration effort into the Neat
>    project and Rigil Salim for his implementation work.
> 
> 9.  References
> 
> 9.1.  Normative references
> 
>    [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
>               Requirement Levels", BCP 14, RFC 2119, March 1997.
> 
>    [RFC2461]  Narten, T., Nordmark, E., and W. Simpson, "Neighbor
>               Discovery for IP Version 6 (IPv6)", RFC 2461, December
>               1998.
> 
>    [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, DOI 10.17487/
>               RFC2818, May 2000,
>               <http://www.rfc-editor.org/info/rfc2818>.
> 
>    [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
>               "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
>               September 2007.
> 
>    [RFC7159]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
>               Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
>               2014, <http://www.rfc-editor.org/info/rfc7159>.
> 
> 9.2.  Informative references
> 
>    [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
>               Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
>               <http://www.rfc-editor.org/info/rfc3339>.
> 
>    [RFC3971]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
>               Neighbor Discovery (SEND)", RFC 3971, March 2005.
> 
>    [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
>               Rose, "Protocol Modifications for the DNS Security
>               Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
>               <http://www.rfc-editor.org/info/rfc4035>.
> 
>    [RFC4191]  Draves, R. and D. Thaler, "Default Router Preferences and
>               More-Specific Routes", RFC 4191, November 2005.
> 
> 
> 
> 
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> 
> 
>    [RFC5785]  Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
>               Uniform Resource Identifiers (URIs)", RFC 5785, DOI
>               10.17487/RFC5785, April 2010,
>               <http://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,
>               <http://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,
>               <http://www.rfc-editor.org/info/rfc6105>.
> 
>    [RFC6106]  Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
>               "IPv6 Router Advertisement Options for DNS Configuration",
>               RFC 6106, November 2010.
> 
>    [RFC6698]  Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
>               of Named Entities (DANE) Transport Layer Security (TLS)
>               Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
>               2012, <http://www.rfc-editor.org/info/rfc6698>.
> 
>    [RFC6724]  Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
>               "Default Address Selection for Internet Protocol Version 6
>               (IPv6)", RFC 6724, September 2012.
> 
>    [RFC7556]  Anipko, D., Ed., "Multiple Provisioning Domain
>               Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015,
>               <http://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,
>               <http://www.rfc-editor.org/info/rfc8028>.
> 
>    [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.
> 
>    [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.
> 
> 
> 
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> 
> 
>    [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.
> 
>    [PEN]      IANA, "Private Enterprise Numbers", <https://www.iana.org/
>               assignments/enterprise-numbers>.
> 
>    [IEEE8021X]
>               IEEE, "IEEE Standards for Local and Metropolitan Area
>               Networks: Port based Network Access Control, IEEE Std", .
> 
>    [github]   Cisco, "IPv6-mPvD github repository", <https://github.com/
>               IPv6-mPvD>.
> 
> 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.
> 
> 
> 
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> 
>       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.
> 
> Appendix B.  Connection monetary cost

I suggest removing this Appendix.  It’s not mentioned in the rest of the document.  The Area Directors should decide if it’s even within scope of this working group.

> 
>    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.
> 
> 
> 
> 
> 
> 
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> 
> 
> 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 the different possibilities for the cost of an elementary
>    billing.  A missing key means "all/unlimited/unrestricted".  If the
>    elementary billing selected has a trafficRemaining of 0 kb, then it
>    means that the user has no access to the network.  Actually, if the
>    last elementary billing has a trafficRemaining parameter, it means
>    that when the user will reach the threshold, he/she will not have
>    access to the network anymore.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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> 
>    +------------------+------------------+--------------+--------------+
>    | Key              | Description      | Type         | JSON Example |
>    +------------------+------------------+--------------+--------------+
>    | pricePerGb       | The price per    | float        | 2            |
>    |                  | Gigabit          | (currency    |              |
>    |                  |                  | 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 a user with 20 GB per month for 40 EUR, then reach a
>    threshold, and with unlimited data during weekends and 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 the host tries to download data from example.com, the conditions
>    of the first elementary billing are fulfilled, so the host takes this
>    elementary billing, finds no cost indication in it and so deduces
>    that it is totally free.  If the host tries to exchange data with
>    foobar.com and the date is 2016-07-14T19:00:00Z, the conditions of
>    the first, second and third elementary billing are not fulfilled.
> 
> 
> 
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> 
>    But the conditions of the fourth are.  So 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, and
>    then pay each MB:
> 
>    [
>      {
>        "beginDate": "2016-02-10T00:00:00Z",
>        "endDate": "2017-02-09T23:59:59Z",
>        "trafficRemaining": 3000000
>      },
>      {
>        "pricePerGb": 30,
>        "currency": "EUR"
>      }
>    ]
> 
> Authors' Addresses
> 
>    Pierre Pfister (editor)
>    Cisco
>    11 Rue Camille Desmoulins
>    Issy-les-Moulineaux  92130
>    France
> 
>    Email: [e-mail]
> 
> 
>    David Schinazi
>    Apple
> 
>    Email: [e-mail]
> 
> 
>    Tommy Pauly
>    Apple
> 
>    Email: [e-mail]
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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> 
> 
>    Eric Vyncke
>    Cisco
>    De Kleetlaan, 6
>    Diegem  1831
>    Belgium
> 
>    Email: [e-mail]
> 
> 
>    Basile Bruneau
>    Ecole Polytechnique
>    Vannes  56000
>    France
> 
>    Email: [e-mail]
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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