draft-ietf-cdni-additional-footprint-types.xml

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<?rfc toc="yes"?>
<?rfc tocompact="yes"?>
<?rfc tocdepth="4"?>
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<rfc category="std" docName="draft-ietf-cdni-additional-footprint-types-12" updates='8008' ipr="trust200902">
    <front>
        <title abbrev="CDNI Additional Footprint Types">
              Content Delivery Network Interconnection (CDNI) Footprint Types: Subdivision Code and Footprint Union
        </title>
        <author fullname="Nir B. Sopher" initials="N." surname="Sopher">
            <organization>
                Qwilt
            </organization>
            <address>
                <postal>
                    <street>
                        6, Ha'harash
                    </street>
                    <city>
                        Hod HaSharon
                    </city>
                    <region>
                    </region>
                    <code>
                        4524079
                    </code>
                    <country>
                        Israel
                    </country>
                </postal>
                <email>
                    nir@apache.org
                </email>
            </address>
        </author>
    <author fullname="Sanjay Mishra" initials="S." surname="Mishra">
      <organization>Verizon</organization>

      <address>
        <postal>
          <street>13100 Columbia Pike</street>

          <city>Silver Spring</city>

          <region>MD</region>

          <code>20904</code>

          <country>USA</country>
        </postal>

        <phone></phone>

        <email>sanjay.mishra@verizon.com</email>
      </address>
    </author>

        <date />
        <abstract>
            <t>
                Open Caching architecture is a use case of Content Delivery Networks Interconnection (CDNI) in which the
                commercial Content Delivery Network (CDN) is the upstream CDN (uCDN) and the ISP caching layer serves as the
                downstream CDN (dCDN). This document supplements the CDNI Metadata footprint types defined in RFC 8006.
                The footprint types defined in this document can be used for footprint objects as part of 
                the Metadata interface (MI) defined in RFC 8006 and for
                the Footprint &amp; Capabilities Advertisement interface (FCI) defined in RFC 8008. By defining the "footprintunion" footprint type,
                this document updates RFC 8008, allowing an additive semantic over the narrowing semantics defined in Appendix B of RFC 8008.
                This document also supplements RFC 9241 with relevant ALTO entity domain types.
                The defined footprint types are derived from requirements raised by Open Caching but are also applicable to CDNI use cases in general.
            </t>
        </abstract>
        
        <note title="Requirements Language">
          <t>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 BCP 14 <xref target="RFC2119"></xref> 
              <xref target="RFC8174"></xref> when, and only when, they
      appear in all capitals, as shown here.</t>
        </note>
    </front>
    <middle>
        <section title="Introduction">
            <t>
                The Streaming Video Technology Alliance <xref target="SVTA" format="default" /> is a global association
                that works to solve streaming video challenges in an effort to improve end-user experience
                and adoption. The Open Caching Working Group <xref target="OCWG" format="default" /> of the
                SVTA is focused on the delegation
                of video delivery requests from commercial Content Delivery Networks (CDNs) to a caching layer at the ISP's network.
                Open Caching architecture is a specific use case of Content Delivery Networks Interconnection (CDNI)
                where the commercial CDN is the
                upstream CDN (uCDN) and the ISP caching layer is the downstream CDN (dCDN).
                The <xref target="OC-RR"> Open Caching Request Routing Specification </xref>
                defines the Request Routing process and the interfaces that are required for its provisioning.
                This document defines and registers CDNI Footprint and Capabilities objects <xref target="RFC8008" />
                that are required for Open Caching Request Routing. 
            </t>
            <t>
                For consistency with other CDNI documents this document follows the
                CDNI convention of uCDN (upstream CDN) and dCDN (downstream CDN) to represent the commercial CDN and ISP caching
                layer respectively.
            </t>
            <t>
                This document registers two CDNI Metadata footprint types (section 7.2 of
                <xref target="RFC8006" />) for the defined objects:
                <list style="symbols">
                    <t>
                        Subdivision code footprint type (e.g., for a dCDN advertising a footprint that is specific to
                        a State in the USA)
                    </t>
                    <t>
                        Footprint union footprint type (for a dCDN advertising a footprint that consists of a group built 
                        from multiple footprints types, e.g., both IPv4 and IPv6 client subnets)
                    </t>
                </list>
            </t>
            <section anchor="terminology" title="Terminology">
                <t>
                    The following terms are used throughout this document:
                    <list style="symbols">
                        <t>
                            CDN - Content Delivery Network
                        </t>
                    </list>
                </t>
                <t>
                    Additionally, this document reuses the terminology defined in
                    <xref target="RFC6707" />,
                    <xref target="RFC7336" />,
                    <xref target="RFC8006" />, and
                    <xref target="RFC8008" />.
                    Specifically, we use the following CDNI acronyms:
                    <list style="symbols">
                        <t>
                            uCDN, dCDN - Upstream CDN and Downstream CDN respectively (see
                            <xref target="RFC7336" />
                            )
                        </t>
                    </list>
                </t>
            </section>
           
        </section>
        <section anchor="cdni-metadata-additional-footprint-types" title="CDNI Metadata Additional Footprint Types">
            <t>
                Section 5 of <xref target="RFC8008" /> describes the Footprint &amp; Capabilities Advertisement interface (FCI) Capability Advertisement object, which
                 includes an array of CDNI footprint objects. Each such object has a footprint type and
                a footprint value, as described in section 4.2.2.2 of <xref target="RFC8006" />.
                This document defines additional footprint types, beyond those mentioned in CDNI metadata
                <xref target="RFC8006" />.
            </t>
            <section anchor="cdni-metadata-subdivisioncode-footprint-type" title="CDNI Metadata &#34;subdivisioncode&#34; Footprint Type">
                <t>
                    Section 4.3.8 of <xref target="RFC8006" />
                    specifies the "countrycode" footprint type
                    for listing <xref target="ISO3166-1"/> alpha-2 codes. Using footprint objects of this type, one can define an
                    FCI Capability Advertisement object footprint constraint that matches a specific country.
                    Herein is defined the "subdivisioncode" simple data type, as well as a footprint type
                    allowing the dCDN to define constraints matching geographic areas
                    with better granularity, specifically using the <xref target="ISO3166-2"/> country subdivision codes.
                </t>
                <section anchor="cdni-metadata-subdivisioncode-data-type" title="CDNI Metadata &#34;subdivisioncode&#34; Data Type">
                    <t>
                        The "subdivisioncode" data type specified in
                        <xref target="cdni-metadata-subdivisioncode-data-type-description" />,
                        describes a country specific subdivision using an <xref target="ISO3166-2"/> code. 
                        The data type is added to the list of data types  described in section 4.3 of
                        <xref target="RFC8006" /> that are used as properties of CDNI Metadata objects.
                    </t>
                    <section anchor="cdni-metadata-subdivisioncode-data-type-description" title="CDNI Metadata &#34;subdivisioncode&#34; Data Type Description">
                        <t>
                        An <xref target="ISO3166-2"/> code in lowercase. Each code consists of two parts separated by a hyphen. 
                        As per <xref target="ISO3166-2"/>, the first part is the <xref target="ISO3166-1"/> code of the country, 
                            and the second part is a string of up to three alphanumeric characters.
                        </t>
                        <t>
                            <list style="empty">
                                <t>
                                    Type: String
                                </t>
                                <t>
                                    Example subdivision codes:
                                </t>
                                <t>"ca-on"</t>
                                <t>"us-ny"</t>
                            </list>
                        </t>
                    </section>
                </section>
                <section anchor="cdni-metadata-subdivisioncode-footprint-type-description" title="CDNI Metadata &#34;subdivisioncode&#34; Footprint Type Description">
                    <t>
                        The "subdivisioncode" simple data type specified in
                        <xref target="cdni-metadata-subdivisioncode-data-type" />, is added
                        to the data types listed as footprint types in section 4.2.2.2 of
                        <xref target="RFC8006" />.
                    </t>
                    <t>
                        Below is an example using a footprint object of type "subdivisioncode". 
                        The footprint object in this example creates a constraint that matches clients in the 
                        state of either New Jersey or New York, USA (ISO <xref target="ISO3166-2"/> codes "US-NJ" and "US-NY" respectively).
                    </t>
                    <figure title="Illustration of subdivision-code footprint advertisement">
                        <artwork>
<![CDATA[
{
  "capabilities": [
    {
      "capability-type": <CDNI capability object type>,
      "capability-value": <CDNI capability object>,
      "footprints": [
          {
              "footprint-type": "subdivisioncode",
              "footprint-value": ["us-nj", "us-ny"]
          }
      ]
    }
  ]
}
]]>
                        </artwork>
                    </figure>
                </section>
                              
            </section>
            <section anchor="cdni-metadata-footprint-union-footprint-type" title="CDNI Metadata &#34;footprintunion&#34; Footprint Type">
                <t>
                    As described in section 5 of <xref target="RFC8008" />, 
                    the FCI Capability Advertisement object includes an array of CDNI footprint objects. 
                    Appendix B of <xref target="RFC8008" /> specifies the
                    semantics of a footprint objects array as a multiple, additive, footprint constraints.
                    This implies that the advertisement of different footprint types narrows
                    the dCDN's candidacy cumulatively.
                </t>
                <t>
                    Sections 4.3.5 and 4.3.6 of <xref target="RFC8006" /> specify the IPv4 CIDR and the IPv6 CIDR
                    footprint types, respectively, for listing IP unscoped address blocks. Using footprint objects of these
                    types, one can define FCI Capability Advertisement object footprint constraints that match IPv4
                    or IPv6 clients. However, the described "narrowing" semantic of the footprint objects array, as described 
                    in Appendix B of <xref target="RFC8008" />, prevents
                    the usage of these objects together to create a footprint constraint that matches IPv4
                    clients together with IPv6 clients.
                </t>
                <t>
                    Below is an example for an attempt at creating an object matching
                    IPv4 clients of subnet "192.0.2.0/24", as well as IPv6 clients of subnet "2001:db8::/32".
                    Such a definition results in an empty list of clients, as the constraints are additives and
                    a client address cannot be both IPv4 and IPv6.
                </t>
                <figure title="Example of narrowing semantic illustrating advertisement of a null footprint">
                    <artwork>
<![CDATA[
{
  "capabilities": [
    {
      "capability-type": <CDNI capability object type>,
      "capability-value": <CDNI capability object>,
      "footprints": [
          {
              "footprint-type": "ipv4cidr",
              "footprint-value": ["192.0.2.0/24"]
          },
          {
              "footprint-type": "ipv6cidr",
              "footprint-value": ["2001:db8::/32"]
          }
      ]
    }
  ]
}
]]>
                    </artwork>
                </figure>
                <t>
                    To overcome the described limitation and allow a list of footprint constraints that
                    match both IPv4 and IPv6 client subnets, this document defines the "footprintunion" footprint type. 
                    This footprint type allows the collection of multiple footprint-objects into a unified object. 
                    Therefore it resolves the above limitation and can be particularly applicable to unify semantically related objects, 
                    for example, an IPv4 CIDR together with an IPv6 CIDR or a country code together with a subdivisoncode. 
                </t>
                <t>
                    Note: to avoid implementation complexity, a "footprintunion" MUST NOT list any "footprintunion" as a value. 
                    As a union of unions is simply a union, this syntactic restriction does not result with any semantic limitation.  
                </t>
                <section anchor="cdni-metadata-footprint-union-data-type" title="CDNI Metadata &#34;footprintunion&#34; Data Type">
                    <t>
                        The "footprintunion" data type is based on the footprint object already defined in 
                        section 4.2.2.2 of <xref target="RFC8006" />. The footprint value for a "footprintunion" object 
                        is an array of footprint objects, where the footprint objects MUST be of any footprint type 
                        other than "footprintunion".
                    </t>
                </section>
                <section anchor="cdni-metadata-footprint-union-footprint-type-description" title="CDNI Metadata &#34;footprintunion&#34; Footprint Type Description">
                    <t>
                        The "footprintunion" data type specified in <xref target="cdni-metadata-footprint-union-data-type" />, 
                        is added to the data types listed as footprint types in section 4.2.2.2 of <xref target="RFC8006" />.
                    </t>
                    <t>
                        Below is an example using a footprint union combining both IPv4 and IPv6 client subnets.
                    </t>
                    <figure title="Example of an advertisement of footprint union for multiple CIDR footprint types">
                        <artwork>
<![CDATA[
{
  "capabilities": [
    {
      "capability-type": <CDNI capability object type>,
      "capability-value": <CDNI capability object>,
      "footprints": [
        {
          "footprint-type": "footprintunion",
          "footprint-value": [
            {
              "footprint-type": "ipv4cidr",
              "footprint-value": ["192.0.2.0/24"]
            },
            {
              "footprint-type": "ipv6cidr",
              "footprint-value": ["2001:db8::/32"]
            }
          ]
        }
      ]
    }
  ]
}
]]>
                        </artwork>
                    </figure>
                    <t>
                    The footprint union also enables composing a country code and subdivision code based footprint objects. 
                    In the example below 
                    we create a constraint covering autonomous system 64496 within the US (ISO <xref target="ISO3166-1"/> alpha-2 code "US")
                    and the Ontario province of Canada (ISO <xref target="ISO3166-2"/> code "CA-ON").
                    </t>
                    <figure title="Example of an advertisement of footprint union for multiple geographical footprint types">
                        <artwork>
<![CDATA[
{
  "capabilities": [
    {
      "capability-type": <CDNI capability object type>,
      "capability-value": <CDNI capability object>,
      "footprints": [
        {
          "footprint-type": "asn",
          "footprint-value": ["as64496"]
        },
        {
          "footprint-type": "footprintunion",
          "footprint-value": [
            {
              "footprint-type": "countrycode",
              "footprint-value": ["us"]
            },
            {
              "footprint-type": "subdivisioncode",
              "footprint-value": ["ca-on"]
            }
          ]
        }
      ]
    }
  ]
}
]]>
                        </artwork>
                    </figure>
                </section>
            </section>
        </section>
        <section anchor="cdni-metadata-alto-property-map-service-entity" title="ALTO Property Map Service Entity">
                <t>
                   Section 6 of <xref target="RFC9241" /> describes how to represent footprint objects as entities in the ALTO property map. The approach is to represent the footprint type as an entity domain type of the ALTO entity,
                   and the footprint value as its domain-specific identifier. <xref target="RFC9241" /> further refers to the representation of footprint objects 
                   of types "asn" and "countrycode". Here we extend this definition to the "subdivisioncode" footprint type.
                 </t>   
                <section anchor="cdni-metadata-subdivisioncode-alto-property-map-service-entity-domain" title="SUBDIVISIONCODE Domain">
                <t>
                    The SUBDIVISIONCODE domain associates property values that defines codes for the names of the principal subdivisions.
                </t>
                <section anchor="cdni-metadata-subdivisioncode-alto-property-map-service-entity-domain-type" title="Entity Domain Type">
                <t>
                    The entity domain type of the SUBDIVISIONCODE domain is "subdivisioncode" (in lowercase).
                </t>
                </section>
                <section anchor="cdni-metadata-subdivisioncode-alto-property-map-service-entity-domain-identifiers" title="Domain-Specific Entity Identifiers">
                <t>
                    The entity identifier of an entity in a SUBDIVISIONCODE is encoded as an alpha-2  <xref target="ISO3166-1"/> country code, followed by a separator 
                    and up to three alphanumeric characters.
                </t>
                </section>
                <section anchor="cdni-metadata-subdivisioncode-alto-property-map-service-entity-hierarchy-and-inheritance" title="Hierarchy and Inheritance">
                <t>
                    There is no hierarchy or inheritance for properties associated with subdivision codes.
                </t>
                </section>
            </section>
            </section>
        <section anchor="IANA" title="IANA Considerations">
            <section anchor="IANA.cdni.metadata.footprint.types" title="CDNI Metadata Footprint Types">
                <t>
                    Section 7.2 of <xref target="RFC8006" /> specifies
                    the "CDNI Metadata Footprint Types" subregistry
                    within the "Content Delivery Network Interconnection (CDNI) Parameters" registry.
                </t>
                <t>
                    This document requests the registration of the two additional footprint types
                    as defined in
                    <xref target="cdni-metadata-subdivisioncode-footprint-type" />
                    and
                    <xref target="cdni-metadata-footprint-union-footprint-type" />
                    :
                </t>
                <texttable>
                    <ttcol align="left">
                        Footprint Type
                    </ttcol>
                    <ttcol align="left">
                        Description
                    </ttcol>
                    <ttcol align="left">
                        Reference
                    </ttcol>
                    <c>
                        subdivisioncode
                    </c>
                    <c>
                        <xref target="ISO3166-2"/> ISO 3166-2 country subdivision code: alpha-2 country code, followed by a hyphen-minus, and up to 3 characters from A-Z;0-9 as a code within the country.
                    </c>
                    <c>
                        RFCthis
                    </c>
                    <c>
                        footprintunion
                    </c>
                    <c>
                        A combination of other footprint objects 
                    </c>
                    <c>
                        RFCthis
                    </c>
                </texttable>
                <t>
                    [RFC Editor: Please replace RFCthis with the published RFC
                    number for this document.]
                </t>
            </section>
             <section anchor="IANA.ALTO.entity.domain.types" title="ALTO Entity Domain Types">
                <t>
                    Section 12.3 of <xref target="RFC9240" /> creates
                    the "ALTO Entity Domain Types" registry.
                </t>
                <t>
                    This document requests the registration of an additional ALTO Entity Domain Types:
               </t>
                <texttable>
                    <ttcol align="left">
                        Identifier
                    </ttcol>
                     <ttcol align="left">
                       Entity Identifier Encoding
                    </ttcol>
                     <ttcol align="left">
                       Hierarchy and Inheritance
                    </ttcol>
                    <ttcol align="left">
                        Media Type of Defining Resource
                    </ttcol>
                    <ttcol align="left">
                        Mapping to ALTO Address Type
                    </ttcol>
                    <c>
                        subdivisioncode
                    </c>
                    <c>
                        See RFCthis, <xref target="cdni-metadata-subdivisioncode-alto-property-map-service-entity-domain-identifiers" /> 
                    </c>
                    <c>
                        None
                    </c>
                    <c>
                        None
                    </c>
                    <c>
                        false 
                    </c>
                    
                </texttable>
                <t>
                    [RFC Editor: Please replace RFCthis with the published RFC
                    number for this document.]
                </t>
                 
                
                 
            </section>
        </section>
        <section anchor="Security" title="Security Considerations">
            <t>
                This specification is in accordance with the CDNI Metadata and the CDNI Request Routing:
                Footprint and Capabilities Semantics. As such, it is subject to the security and confidentiality considerations as
                defined in Section 8 of
                <xref target="RFC8006" />
                and in Section 7 of
                <xref target="RFC8008" />
                respectively.
            </t>
        </section>
        <section anchor="Acknowledgements" title="Acknowledgements">
            <t>
                The authors would like to express their gratitude to Ori Finkelman and
                Kevin J. Ma for their guidance and reviews throughout the development of this
                document. We would also like to thank all the Area Directors for their review and feedback in improving this document. 
            </t>
        </section>
    </middle>
    <back>
        <references title="Normative References">
            <?rfc include="reference.RFC.2119"?>
            <?rfc include="reference.RFC.8006"?>
            <?rfc include="reference.RFC.8008"?>
            <?rfc include="reference.RFC.8174"?>
            <?rfc include="reference.RFC.9240"?>
            <?rfc include="reference.RFC.9241"?>
            <reference anchor="ISO3166-1" target="https://www.iso.org/standard/72482.html">
                <front>
                <title>
                    Codes for the representation of names of countries and their subdivisions -- Part 1: Country code
                </title>
                <author>
                    <organization>ISO</organization>
                </author>
                <date month="08" year="2020"/>
                </front>
                <seriesInfo name="ISO" value="3166-1:2020"/>
                <seriesInfo name="Edition" value="4"/>
            </reference>

            <reference anchor="ISO3166-2" target="https://www.iso.org/standard/72483.html">
                <front>
                <title>
                    Codes for the representation of names of countries and their subdivisions -- Part 2: Country subdivision code
                </title>
                <author>
                    <organization>ISO</organization>
                </author>
                <date month="08" year="2020"/>
                </front>
                <seriesInfo name="ISO" value="3166-2:2020"/>
                <seriesInfo name="Edition" value="4"/>
            </reference>
        </references>

        <references title="Informative References">
            <?rfc include="reference.RFC.6707"?>
            <?rfc include="reference.RFC.7336"?>
            <reference anchor="SVTA" target="https://www.svta.org/">
                <front>
                    <title>
                        Streaming Video Technology Alliance Home Page
                    </title>
                    <author />
                    <date />
                </front>
            </reference>
            <reference anchor="OCWG" target="https://opencaching.svta.org/">
                <front>
                    <title>
                        Open Caching Home Page
                    </title>
                    <author />
                    <date />
                </front>
            </reference>
            <reference anchor="OC-RR" target="https://www.svta.org/product/open-cache-request-routing-functional-specification/">
                <front>
                    <title>
                        Open Caching - Request Routing Functional Specification
                    </title>
                    <author initials="O." surname="Finkelman" fullname="Ori Finkelman" role="editor">
                        <organization>
                            Qwilt
                        </organization>
                    </author>
                    <author initials="J." surname="Hofmann" fullname="Jason Hofmann">
                        <organization>
                            Limelight Networks
                        </organization>
                    </author>
                    <author initials="E." surname="Klein" fullname="Eric Klein">
                        <organization>
                            Disney Streaming Services
                        </organization>
                    </author>
                    <author initials="S." surname="Mishra" fullname="Sanjay Mishra">
                        <organization>
                            Verizon
                        </organization>
                    </author>
                    <author initials="K." surname="Ma" fullname="Kevin J. Ma">
                        <organization>
                            Disney Streaming Services
                        </organization>
                    </author>
                    <author initials="D." surname="Sahar" fullname="Dan Sahar">
                        <organization>
                            Qwilt
                        </organization>
                    </author>
                    <author initials="B." surname="Zurat" fullname="Bill Zurat">
                        <organization>
                            Disney Streaming Services
                        </organization>
                    </author>
                    <date day="15" month="January" year="2021" />
                </front>
                <seriesInfo name="Version" value="2.0" />
            </reference>
        </references>
    </back>
</rfc>