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/. Sopher & Mishra Expires 27 July 2023 [Page 1] Internet-Draft CDNI Additional Footprint Types January 2023 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 Sopher & Mishra Expires 27 July 2023 [Page 2] Internet-Draft CDNI Additional Footprint Types January 2023 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] ) Sopher & Mishra Expires 27 July 2023 [Page 3] Internet-Draft CDNI Additional Footprint Types January 2023 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]. Sopher & Mishra Expires 27 July 2023 [Page 4] Internet-Draft CDNI Additional Footprint Types January 2023 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": , "capability-value": , "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. Sopher & Mishra Expires 27 July 2023 [Page 5] Internet-Draft CDNI Additional Footprint Types January 2023 { "capabilities": [ { "capability-type": , "capability-value": , "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". Sopher & Mishra Expires 27 July 2023 [Page 6] Internet-Draft CDNI Additional Footprint Types January 2023 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": , "capability-value": , "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"). Sopher & Mishra Expires 27 July 2023 [Page 7] Internet-Draft CDNI Additional Footprint Types January 2023 { "capabilities": [ { "capability-type": , "capability-value": , "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. Sopher & Mishra Expires 27 July 2023 [Page 8] Internet-Draft CDNI Additional Footprint Types January 2023 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.] Sopher & Mishra Expires 27 July 2023 [Page 9] Internet-Draft CDNI Additional Footprint Types January 2023 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 Sopher & Mishra Expires 27 July 2023 [Page 10] Internet-Draft CDNI Additional Footprint Types January 2023 [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, . [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, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [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, . [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [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, . 7.2. Informative References Sopher & Mishra Expires 27 July 2023 [Page 11] Internet-Draft CDNI Additional Footprint Types January 2023 [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, . [OCWG] "Open Caching Home Page", . [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, . [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, . [SVTA] "Streaming Video Technology Alliance Home Page", . 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 Sopher & Mishra Expires 27 July 2023 [Page 12]