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Content Delivery Network Interconnection (CDNI) Footprint Types: Subdivision Code and Footprint Union
draft-ietf-cdni-additional-footprint-types-11

Document Type Active Internet-Draft (cdni WG)
Authors Nir Baruch Sopher , Sanjay Mishra
Last updated 2023-01-26 (Latest revision 2023-01-23)
Replaces draft-sopher-cdni-footprint-types-extensions
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
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Reviews
Additional resources Mailing list discussion
Stream WG state Submitted to IESG for Publication
Associated WG milestone
Sep 2022
Submit specification of CDNI Footprint Type Extensions to IESG as Proposed Standard
Document shepherd Kevin J. Ma
Shepherd write-up Show Last changed 2022-10-23
IESG IESG state RFC Ed Queue
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(None)
Consensus boilerplate Yes
Telechat date (None)
Responsible AD Francesca Palombini
Send notices to kevin.j.ma.ietf@gmail.com
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack
IANA expert review state Expert Reviews OK
RFC Editor RFC Editor state EDIT
Details
draft-ietf-cdni-additional-footprint-types-11
Network Working Group                                          N. Sopher
Internet-Draft                                                     Qwilt
Updates: 8008 (if approved)                                    S. Mishra
Intended status: Standards Track                                 Verizon
Expires: 27 July 2023                                    23 January 2023

    Content Delivery Network Interconnection (CDNI) Footprint Types:
                  Subdivision Code and Footprint Union
             draft-ietf-cdni-additional-footprint-types-11

Abstract

   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 & Capabilities Advertisement interface (FCI) defined in RFC
   8008.  By defining the footprint union 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.

Requirements Language

   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 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

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/.

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   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 27 July 2023.

Copyright Notice

   Copyright (c) 2023 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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  CDNI Metadata Additional Footprint Types  . . . . . . . . . .   4
     2.1.  CDNI Metadata Subdivision Code Footprint Type . . . . . .   4
       2.1.1.  CDNI Metadata Subdivision Code Data Type  . . . . . .   4
         2.1.1.1.  CDNI Metadata Subdivision Code Data Type
                 Description . . . . . . . . . . . . . . . . . . . .   4
       2.1.2.  CDNI Metadata Subdivision Code Footprint Type
               Description . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  CDNI Metadata Footprint Union Footprint Type  . . . . . .   5
       2.2.1.  CDNI Metadata Footprint Union Data Type . . . . . . .   6
       2.2.2.  CDNI Metadata FootprintUnion Footprint Type
               Description . . . . . . . . . . . . . . . . . . . . .   7
   3.  ALTO Property Map Service Entity  . . . . . . . . . . . . . .   8
     3.1.  SUBDIVISIONCODE Domain  . . . . . . . . . . . . . . . . .   8
       3.1.1.  Entity Domain Type  . . . . . . . . . . . . . . . . .   9
       3.1.2.  Domain-Specific Entity Identifiers  . . . . . . . . .   9
       3.1.3.  Hierarchy and Inheritance . . . . . . . . . . . . . .   9
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     4.1.  CDNI Metadata Footprint Types . . . . . . . . . . . . . .   9
     4.2.  ALTO Entity Domain Types  . . . . . . . . . . . . . . . .  10
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  10

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     7.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   The Streaming Video Technology Alliance [SVTA] 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 [OCWG] 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
   Open Caching Request Routing Specification [OC-RR] defines the
   Request Routing process and the interfaces that are required for its
   provisioning.  This document defines and registers CDNI Footprint and
   Capabilities objects [RFC8008] that are required for Open Caching
   Request Routing.

   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.

   This document registers two CDNI Metadata Footprint Types (section
   7.2 of [RFC8006]) for the defined objects:

   *  Subdivision Code Footprint Type (e.g., for a dCDN advertising a
      footprint that is specific to a State in the USA)

   *  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)

1.1.  Terminology

   The following terms are used throughout this document:

   *  CDN - Content Delivery Network

   Additionally, this document reuses the terminology defined in
   [RFC6707], [RFC7336], [RFC8006], and [RFC8008].  Specifically, we use
   the following CDNI acronyms:

   *  uCDN, dCDN - Upstream CDN and Downstream CDN respectively (see
      [RFC7336] )

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2.  CDNI Metadata Additional Footprint Types

   Section 5 of [RFC8008] describes the Footprint & 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 [RFC8006].  This document defines additional footprint types,
   beyond those mentioned in CDNI metadata [RFC8006].

2.1.  CDNI Metadata Subdivision Code Footprint Type

   Section 4.3.8 of [RFC8006] specifies the "Country Code" footprint
   type for listing [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 [ISO3166-2]
   Country Subdivision codes.

2.1.1.  CDNI Metadata Subdivision Code Data Type

   The "subdivisioncode" data type specified in Section 2.1.1.1,
   describes a country specific subdivision using an [ISO3166-2] code.
   The data type is added to the list of data types described in section
   4.3 of [RFC8006] that are used as properties of CDNI Metadata
   objects.

2.1.1.1.  CDNI Metadata Subdivision Code Data Type Description

   An [ISO3166-2] code in lowercase.  Each code consists of two parts
   separated by a hyphen.  As per [ISO3166-2], the first part is the
   [ISO3166-1] code of the country, and the second part is a string of
   up to three alphanumeric characters.

      Type: String

      Example Subdivision Codes:

      "ca-on"

      "us-ny"

2.1.2.  CDNI Metadata Subdivision Code Footprint Type Description

   The "subdivisioncode" simple data type specified in Section 2.1.1, is
   added to the data types listed as footprint types in section 4.2.2.2
   of [RFC8006].

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   Below is an example using a footprint object of type
   "subdivisioncode".  The Footprint Object in this example creates a
   constraint matching clients in the states of New Jersey and New York,
   USA (ISO [ISO3166-2] codes "US-NJ" and "US-NY" respectively).

   {
     "capabilities": [
       {
         "capability-type": <CDNI capability object type>,
         "capability-value": <CDNI capability object>,
         "footprints": [
             {
                 "footprint-type": "subdivisioncode",
                 "footprint-value": ["us-nj", "us-ny"]
             }
         ]
       }
     ]
   }

     Figure 1: Illustration of subdivision-code footprint advertisement

2.2.  CDNI Metadata Footprint Union Footprint Type

   As described in section 5 of [RFC8008], the FCI Capability
   Advertisement Object includes an array of CDNI Footprint Objects.
   Appendix B of [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.

   Sections 4.3.5 and 4.3.6 of [RFC8006] specify the "IPv4CIDR" and
   "IPv6CIDR" 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 [RFC8008], prevents the usage of these objects together to create
   a footprint constraint that matches IPv4 clients together with IPv6
   clients.

   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.

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   {
     "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"]
             }
         ]
       }
     ]
   }

            Figure 2: Example of narrowing semantic illustrating
                     advertisement of a null footprint

   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 ipv4cidr together with an ipv6cidr or a countrycode
   together with a subdivisoncode.

   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.

2.2.1.  CDNI Metadata Footprint Union Data Type

   The "footprintunion" data type is based on the Footprint Object
   already defined in section 4.2.2.2 of [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".

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2.2.2.  CDNI Metadata FootprintUnion Footprint Type Description

   The "footprintunion" data type specified in Section 2.2.1, is added
   to the data types listed as footprint types in section 4.2.2.2 of
   [RFC8006].

   Below is an example using a footprint object of type "footprintunion"
   combining both IPv4 and IPv6 client subnets.

   {
     "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"]
               }
             ]
           }
         ]
       }
     ]
   }

        Figure 3: Example of an advertisement of footprint union for
                       multiple CIDR footprint types

   The footprint union also enables composing a countrycode and
   subdivisioncode based footprint objects.  In the example below we
   create a constraint covering autonomous system 64496 within the US
   (ISO [ISO3166-1] alpha-2 code "US") and the Ontario province of
   Canada (ISO [ISO3166-2] code "CA-ON").

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   {
     "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"]
               }
             ]
           }
         ]
       }
     ]
   }

   Figure 4: Example of an advertisement of footprint union for multiple
                        geographical footprint types

3.  ALTO Property Map Service Entity

   Section 6 of [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.  [RFC9241]
   further refers to the representation of footprint objects of types
   "asn" and "countrycode".  Here we extend this definition to the
   "subdivisioncode" footprint-type.

3.1.  SUBDIVISIONCODE Domain

   The SUBDIVISIONCODE domain associates property values that defines
   codes for the names of the principal subdivisions.

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3.1.1.  Entity Domain Type

   The entity domain type of the SUBDIVISIONCODE domain is
   "subdivisioncode" (in lowercase).

3.1.2.  Domain-Specific Entity Identifiers

   The entity identifier of an entity in a SUBDIVISIONCODE is encoded as
   an alpha-2 [ISO3166-1] Country Code, followed by a separator and up
   to three alphanumeric characters.

3.1.3.  Hierarchy and Inheritance

   There is no hierarchy or inheritance for properties associated with
   subdivision codes.

4.  IANA Considerations

4.1.  CDNI Metadata Footprint Types

   Section 7.2 of [RFC8006] specifies the "CDNI Metadata Footprint
   Types" subregistry within the "Content Delivery Network
   Interconnection (CDNI) Parameters" registry.

   This document requests the registration of the two additional
   Footprint Types as defined in Section 2.1 and Section 2.2 :

   +=================+=====================================+===========+
   | Footprint Type  | Description                         | Reference |
   +=================+=====================================+===========+
   | subdivisioncode | [ISO3166-2] ISO 3166-2 country      | RFCthis   |
   |                 | 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.            |           |
   +-----------------+-------------------------------------+-----------+
   | footprintunion  | A combination of other              | RFCthis   |
   |                 | Footprint Objects                   |           |
   +-----------------+-------------------------------------+-----------+

                                  Table 1

   [RFC Editor: Please replace RFCthis with the published RFC number for
   this document.]

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4.2.  ALTO Entity Domain Types

   Section 12.3 of [RFC9240] creates the "ALTO Entity Domain Types"
   registry.

   This document requests the registration of an additional ALTO Entity
   Domain Types:

    +=================+============+=============+==========+=========+
    | Identifier      | Entity     | Hierarchy   | Media    | Mapping |
    |                 | Identifier | and         | Type of  | to ALTO |
    |                 | Encoding   | Inheritance | Defining | Address |
    |                 |            |             | Resource | Type    |
    +=================+============+=============+==========+=========+
    | subdivisioncode | See        | None        | None     | false   |
    |                 | RFCthis,   |             |          |         |
    |                 | Section    |             |          |         |
    |                 | 3.1.2      |             |          |         |
    +-----------------+------------+-------------+----------+---------+

                                  Table 2

   [RFC Editor: Please replace RFCthis with the published RFC number for
   this document.]

5.  Security Considerations

   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 [RFC8006] and in Section 7 of [RFC8008]
   respectively.

6.  Acknowledgements

   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.

7.  References

7.1.  Normative References

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   [ISO3166-1]
              ISO, "Codes for the representation of names of countries
              and their subdivisions -- Part 1: Country code",
              ISO 3166-1:2020, Edition 4, August 2020,
              <https://www.iso.org/standard/72482.html>.

   [ISO3166-2]
              ISO, "Codes for the representation of names of countries
              and their subdivisions -- Part 2: Country subdivision
              code", ISO 3166-2:2020, Edition 4, August 2020,
              <https://www.iso.org/standard/72483.html>.

   [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>.

   [RFC8006]  Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
              "Content Delivery Network Interconnection (CDNI)
              Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
              <https://www.rfc-editor.org/info/rfc8006>.

   [RFC8008]  Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
              R., and K. Ma, "Content Delivery Network Interconnection
              (CDNI) Request Routing: Footprint and Capabilities
              Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
              <https://www.rfc-editor.org/info/rfc8008>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC9240]  Roome, W., Randriamasy, S., Yang, Y., Zhang, J., and K.
              Gao, "An Extension for Application-Layer Traffic
              Optimization (ALTO): Entity Property Maps", RFC 9240,
              DOI 10.17487/RFC9240, July 2022,
              <https://www.rfc-editor.org/info/rfc9240>.

   [RFC9241]  Seedorf, J., Yang, Y., Ma, K., Peterson, J., and J. Zhang,
              "Content Delivery Network Interconnection (CDNI) Footprint
              and Capabilities Advertisement Using Application-Layer
              Traffic Optimization (ALTO)", RFC 9241,
              DOI 10.17487/RFC9241, July 2022,
              <https://www.rfc-editor.org/info/rfc9241>.

7.2.  Informative References

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   [OC-RR]    Finkelman, O., Ed., Hofmann, J., Klein, E., Mishra, S.,
              Ma, K., Sahar, D., and B. Zurat, "Open Caching - Request
              Routing Functional Specification", Version 2.0, 15 January
              2021, <https://www.svta.org/product/open-cache-request-
              routing-functional-specification/>.

   [OCWG]     "Open Caching Home Page", <https://opencaching.svta.org/>.

   [RFC6707]  Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
              Distribution Network Interconnection (CDNI) Problem
              Statement", RFC 6707, DOI 10.17487/RFC6707, September
              2012, <https://www.rfc-editor.org/info/rfc6707>.

   [RFC7336]  Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
              "Framework for Content Distribution Network
              Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
              August 2014, <https://www.rfc-editor.org/info/rfc7336>.

   [SVTA]     "Streaming Video Technology Alliance Home Page",
              <https://www.svta.org/>.

Authors' Addresses

   Nir B. Sopher
   Qwilt
   6, Ha'harash
   Hod HaSharon
                4524079
   Israel
   Email: nir@apache.org

   Sanjay Mishra
   Verizon
   13100 Columbia Pike
   Silver Spring, MD 20904
   United States of America
   Email: sanjay.mishra@verizon.com

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