CDNI Request Routing Extensions

The Streaming Video Alliance 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 of the Streaming Video Alliance is focused on the delegation of video delivery requests from commerical CDNs to a caching layer at the ISP's network. Open Caching architecture is a specific use case of 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 defines the Request Routing process and the interfaces that are required for its provisioning. This document defines and registers CDNI Footprint and Capabilities objects 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 ) for the defined objects: IPv4v6CIDR Footprint Type (for dCDN advertising a footprint that consists of both IPv4 and IPv6 client addresses) ISO3166Code Footprint Type (e.g. for dCDN advertising a footprint that is specific to a State in the USA)

The following terms are used throughout this document: CDN - Content Delivery Network Additionally, this document reuses the terminology defined in , , , , , and . Specifically, we use the following CDNI acronyms: uCDN, dCDN - Upstream CDN and Downstream CDN respectively (see )

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 when, and only when, they appear in all capitals, as shown here.

Section 5 of describes the 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 . This document defines additional footprint types, beyond those mentioned in CDNI metadata . For consistency, this document follows the CDNI notation of uCDN for (the commercial CDN) and dCDN (the ISP caching layer).

As described in section 5 of , the FCI Capability Advertisement Object includes an array of CDNI Footprint Objects. Appendix B of specifies the semantics of a Footprint Objects array as a multiple, additive, footprint constraints. Meaning, the advertisement of different footprint types narrows the dCDN's candidacy cumulatively. Sections 4.3.5 and 4.3.6 of specify the "IPv4CIDR" and "IPv6CIDR" footprint types, respectively, for listing IP addresses blocks. Using Footprint Objects of these types, one can define an FCI Capability Advertisement Object footprint constraints that match IPv4 or IPv6 clients. However, the described "narrowing" semantic of the Footprint Objects array prevents the usage of these objects together in order 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 with an empty list of clients, as the constraints are additives and a client address cannot be both IPv4 and IPv6.

, "capability-value": , }, "footprints": [ { "footprint-type": "ipv4cidr", "footprint-value": ["192.0.2.0/24"] }, { "footprint-type": "ipv6cidr", "footprint-value": ["2001:db8::/32"] } ] } ] } ]]> To overcome the described limitation and allow a list of footprint constraints that matches both IPv4 and IPv6 client addresses, we introduce below the "IPv4v6CIDR" simple data type as well as a derived footprint type.

The "IPv4v6CIDR" data type specified in , can be either IPv4 or IPv6 address blocks. The data type is added to the list of data types described in section 4.3 of that are used as properties of CDNI Metadata objects.

Either an IPv4CIDR property or IPv6CIDR property, as described in sections 4.3.5 and 4.3.6 of respectively. Type: String Example IPv4v6CIDRs: "192.0.2.0/24" "2001:db8::/32"

The "IPv4v6CIDR" simple data type specified in , is added to the data types listed as footprint types in section 4.2.2.2 of . Below is an adjustment for the example in , now embedding a footprint object of type "IPv4v6CIDR".

, "capability-value": , }, "footprints": [ { "footprint-type": "ipv4v6cidr", "footprint-value": ["192.0.2.0/24", "2001:db8::/32"] } ] } ] } ]]>

Section 4.3.8 of specifies the "Country Code" footprint type for listing alpha-2 codes. Using Footprint Objects of this type, one can define an FCI Capability Advertisement Object footprint constraints that match a specific country. Here we define the iso3166code simple data type, as well as a footprint type allowing the dCDN to define constraints matching geographic areas with better granularity, specifically using the Country Subdivision codes.

The "ISO3166Code" data type specified in , can either describe a country based on an alpha-2 code, or describe a more specific subdivision using an code. The data type is added to the list of data types described in section 4.3 of that are used as properties of CDNI Metadata objects.

Either an alpha-2 code in lowercase, or such a code followed by a dash as well as a more specific subdivision alphanumeric code in lowercase. Type: String Example ISO3166Codes: "ca" "us-ny"

The "ISO3166Code" simple data type specified in , is added to the data types listed as footprint types in section 4.2.2.2 of . Below is an adjustment for the example in , now embedding a footprint object of type "ISO3166Code". The Footprint Object in this example creates a constraints matching clients both in Canada (ISO alpha-2 code "CA") as well as in the state of New-York (ISO Subdivision code "NY") in the (ISO alpha-2 code "US").

, "capability-value": , }, "footprints": [ { "footprint-type": "iso3166code", "footprint-value": ["ca", "us-ny"] } ] } ] } ]]>

As described in section 7.2 of , the "CDNI Metadata Footprint Types" subregistry was created within the "Content Delivery Network Interconnection (CDNI) Parameters" registry. The created namespace defines the valid values for Footprint Object Types, and is already populated with the types described in Section 4.2.2.2 of . This document requests the registration of the two additional footprint type as defined in and : Footprint Type Description Specification ipv4v6cidr IPv4/IPv6 address block RFCthis iso3166code ISO 3166-1/2 Country or Subdivision Code RFCthis [RFC Editor: Please replace RFCthis with the published RFC number for this document.]

This specification is in accordance with the CDNI Request Routing: Footprint and Capabilities Semantics. As such, it is subject to the security and privacy considerations as defined in Section 8 of and in Section 7 of respectively.

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.