The document shepherd is Francois Le Faucheur. The responsible AD is Barry Leiba. The requested RFC status is Informational.
This document describes the semantic of a footprint and capability advertisement function usable by interconnected CDNs allowing downstream CDNs (dCDNs) to advertise capabilities and the coverage footprint of those capabilities to upstream CDNs (uCDNs). This function is to be supported by the CDNI Footprint & Capabilities interface (FCI) identified in the CDNI Framework (RFC 7336). The FCI is intended to help an uCDN decides whether or not to delegate requests to a given dCDN.
The WG had extensive discussions about the potential scope of the CDNI Footprint & Capabilities interface (FCI); this document provides a useful record of the key aspects of that discussion and the conclusions as to the scope agreed by the WG for FCI. Based on this, the document also captures the semantics of the FCI, defines a Base Advertisement Object, defines the necessary registries and provides guidelines on how these registries may be extended in the future. The document does not define, nor select, a specific protocol to realise the FCI interface.
2. Review and Consensus
The document contains historical information discussing and defining the scope of FCI (e.g., non-real-time updates, with no attempts to prevent CDNs from lying about footprints, and without requiring CDNs to divulge topology or capacity information). There was a long history of debate over these issues, but consensus was reached. This document defines the broad WG consensus on a minimum set of capabilities to be advertised, and the WG consensus on a minimum set of footprint types to support, with registries created for the future extensibility of both. The document also defines an abstract object for defining new capabilities and footprints. This document is intended to provide guidance for the FCI interface standards track documents.
An independent review was performed by Iuniana Oprescu; all comments were addressed.
A large discussion took place over logistical issues around how to handle common references between FCI and CDNI Metadata, CDNI Logging, and CDNI Redirection interfaces. A broad consensus was reached after many small design team meetings were held to consider options. The current IANA registry and media type structure is the result.
As document shepherd, I performed a final review including IANA considerations and normative references, as well as citing editorial and consistency issues; all comments were addressed.
3. Intellectual Property
Each author has confirmed conformance with BCP 78/79.
There was one IPR disclosure from Juniper Networks. The disclosure was announced on the list with only one response on the list stating that the RAND-like terms seemed reasonable. The disclosure was also discussed in the WG meeting at IETF94. The chairs, as individuals, agreed that the RAND-like terms seemed reasonable and that they did not see any reason to hold up the document and, as chairs, proposed to go ahead with current plans to progress the document, and asked if anyone had any objection. There were no objections from the WG.
4. Other Points
There are no downward references in the document.
The IANA Considerations registers three new CDNI Paylod Types. One of the Authors is lined up as the designated expert reviewer for the CDNI Protocol Types registry.
The IANA Considerations also creates a new registry for redirection modes, providing sufficient guidelines to IANA. One of the Authors is lined up as the designated expert reviewer for the CDNI Capabilities Redirection Modes registry.