draft-ietf-cdni-request-routing-extensions-08.txt		rfc8804.txt
	Network Working Group O. Finkelman		Internet Engineering Task Force (IETF) O. Finkelman
	Internet-Draft Qwilt		Request for Comments: 8804 Qwilt
	Intended status: Standards Track S. Mishra		Category: Standards Track S. Mishra
	Expires: May 23, 2020 Verizon		ISSN: 2070-1721 Verizon
	November 20, 2019		September 2020
	CDNI Request Routing Extensions		Content Delivery Network Interconnection (CDNI) Request Routing
	draft-ietf-cdni-request-routing-extensions-08		Extensions
	Abstract		Abstract
	Open Caching architecture is a use case of Content Delivery Networks		Open Caching architecture is a use case of Content Delivery Network
	Interconnection (CDNI) in which the commercial Content Delivery		Interconnection (CDNI) in which the commercial Content Delivery
	Network (CDN) is the upstream CDN (uCDN) and the ISP caching layer		Network (CDN) is the upstream CDN (uCDN) and the ISP caching layer
	serves as the downstream CDN (dCDN). The extensions specified in		serves as the downstream CDN (dCDN). This document defines
	this document to the CDNI Metadata Interface (MI) and the Footprint		extensions to the CDNI Metadata Interface (MI) and the Footprint &
	and Capabilities Interface (FCI) are derived from requirements raised		Capabilities Advertisement interface (FCI). These extensions are
	by Open Caching but are also applicable to CDNI use cases in general.		derived from requirements raised by Open Caching but are also
			applicable to CDNI use cases in general.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This is an Internet Standards Track document.
	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/.
	Internet-Drafts are draft documents valid for a maximum of six months		This document is a product of the Internet Engineering Task Force
	and may be updated, replaced, or obsoleted by other documents at any		(IETF). It represents the consensus of the IETF community. It has
	time. It is inappropriate to use Internet-Drafts as reference		received public review and has been approved for publication by the
	material or to cite them other than as "work in progress."		Internet Engineering Steering Group (IESG). Further information on
			Internet Standards is available in Section 2 of RFC 7841.
	This Internet-Draft will expire on May 23, 2020.		Information about the current status of this document, any errata,
			and how to provide feedback on it may be obtained at
			https://www.rfc-editor.org/info/rfc8804.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2020 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology
	1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3		1.2. Requirements Language
	2. Redirect Target Capability . . . . . . . . . . . . . . . . . 4		2. Redirect Target Capability
	2.1. DNS Redirect Target . . . . . . . . . . . . . . . . . . . 5		2.1. DNS Redirect Target
	2.2. HTTP Redirect Target . . . . . . . . . . . . . . . . . . 5		2.2. HTTP Redirect Target
	2.3. Properties of Redirect Target Capability Object . . . . . 5		2.3. Properties of Redirect Target Capability Object
	2.4. DnsTarget Object . . . . . . . . . . . . . . . . . . . . 7		2.4. DnsTarget Object
	2.4.1. DNS Target Example . . . . . . . . . . . . . . . . . 7		2.4.1. DnsTarget Example
	2.5. HttpTarget Object . . . . . . . . . . . . . . . . . . . . 8		2.5. HttpTarget Object
	2.5.1. HTTP Target Example . . . . . . . . . . . . . . . . . 9		2.5.1. HttpTarget Example
	2.6. Usage Example . . . . . . . . . . . . . . . . . . . . . . 10		2.6. Usage Example
	3. Fallback Target Address Metadata . . . . . . . . . . . . . . 11		3. Fallback Target Server Address
	3.1. Properties of Fallback Target Address Metadata Object . . 12		3.1. Properties of Fallback Target Generic Metadata Object
	3.2. Usage Example . . . . . . . . . . . . . . . . . . . . . . 13		3.2. Usage Example
	3.3. uCDN addressing considerations . . . . . . . . . . . . . 15		3.3. uCDN Addressing Considerations
	4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16		4. IANA Considerations
	4.1. CDNI Payload Types . . . . . . . . . . . . . . . . . . . 16		4.1. CDNI Payload Types
	4.1.1. CDNI FCI RedirectTarget Payload Type . . . . . . . . 16		4.1.1. CDNI FCI RedirectTarget Payload Type
	4.1.2. CDNI MI FallbackTarget Payload Type . . . . . . . . . 16		4.1.2. CDNI MI FallbackTarget Payload Type
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 17		5. Security Considerations
	5.1. Confidentiality and Privacy . . . . . . . . . . . . . . . 17		5.1. Confidentiality and Privacy
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17		6. References
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 17		6.1. Normative References
	7.1. Normative References . . . . . . . . . . . . . . . . . . 17		6.2. Informative References
	7.2. Informative References . . . . . . . . . . . . . . . . . 18		Acknowledgements
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19		Authors' Addresses
	1. Introduction		1. Introduction
	The Streaming Video Alliance [SVA] is a global association that works		The Streaming Video Alliance [SVA] is a global association that works
	to solve streaming video challenges in an effort to improve end-user		to solve streaming video challenges in an effort to improve end-user
	experience and adoption. The Open Caching Working Group [OCWG] of		experience and adoption. The Open Caching Working Group [OCWG] of
	the Streaming Video Alliance [SVA] is focused on the delegation of		the Streaming Video Alliance [SVA] is focused on the delegation of
	video delivery requests from commercial CDNs to a caching layer at		video delivery requests from commercial CDNs to a caching layer at
	the Internet Service Provider's (ISP) network. Open Caching		the ISP's network. Open Caching architecture is a specific use case
	architecture is a specific use case of CDNI where the commercial CDN		of CDNI where the commercial CDN is the upstream CDN (uCDN) and the
	is the upstream CDN (uCDN) and the ISP caching layer is the		ISP caching layer is the downstream CDN (dCDN). The Open Caching
	downstream CDN (dCDN). The Open Caching Request Routing		Request Routing Functional Specification [OC-RR] defines the Request
	Specification [OC-RR] defines the Request Routing process and the		Routing process and the interfaces that are required for its
	interfaces that are required for its provisioning. This document		provisioning. This document defines the CDNI metadata object
	defines and registers CDNI metadata object [RFC8006] and CDNI		[RFC8006] and the CDNI Footprint and Capabilities object [RFC8008]
	Footprint and Capabilities object [RFC8008] that are required for		that are required for Open Caching Request Routing:
	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 also registers CDNI Payload Types [RFC7736] for the
	defined objects:
	o Redirect Target Capability (for dCDN advertising redirect target		* Redirect Target Capability (for dCDN advertising redirect target
	address)		address)
	o Fallback Target Metadata (for uCDN configuring fallback target		* Fallback Target Metadata (for uCDN configuring fallback target
	address)		address)
			This document also registers CDNI Payload Types [RFC7736] for these
			defined objects.
			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.
	1.1. Terminology		1.1. Terminology
	The following terms are used throughout this document:		The following terms are used throughout this document:
	o FQDN - Fully Qualified Domain Name		FQDN Fully Qualified Domain Name
	o CDN - Content Delivery Network		CDN Content Delivery Network
	Additionally, this document reuses the terminology defined in		Additionally, this document reuses the terminology defined in
	[RFC6707], [RFC7336], [RFC8006], [RFC8007], and [RFC8008].		[RFC6707], [RFC7336], [RFC8006], [RFC8007], and [RFC8008].
	Specifically, we use the following CDNI acronyms:		Specifically, we use the following CDNI acronyms:
	o FCI - Footprint and Capability Interface (see [RFC8008])		FCI Footprint & Capabilities Advertisement interface (see
			[RFC8008])
	o MI - Metadata Interface (see [RFC8006])		MI Metadata Interface (see [RFC8006])
	o uCDN, dCDN - Upstream CDN and Downstream CDN respectively (see		uCDN Upstream CDN (see [RFC7336])
	[RFC7336])
	o RT - Redirection Target. Endpoint for redirection from uCDN to		dCDN Downstream CDN (see [RFC7336])
	dCDN.
	o RR - Request Router. An element responsible for routing user		RT Redirection Target. Endpoint for redirection from uCDN to
	requests, typically using HTTP redirect or DNS CNAME, depending on		dCDN.
	the use case.
			RR Request Router. An element responsible for routing user
			requests, typically using HTTP redirect or DNS CNAME,
			depending on the use case.
	1.2. Requirements Language		1.2. Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP		"OPTIONAL" in this document are to be interpreted as described in
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here.
	2. Redirect Target Capability		2. Redirect Target Capability
	Iterative request redirection is defined in Section 1.1 of [RFC7336]		Iterative CDNI Request Redirection is defined in Section 1.1 of
	and elaborated by examples in Sections 3.2 and 3.4 of [RFC7336]. A		[RFC7336] and elaborated by examples in Sections 3.2 and 3.4 of
	Redirection Target (RT) is defined in Section 2 of [RFC7975] for		[RFC7336]. A Redirection Target (RT) is defined in Section 2 of
	Recursive Request Redirection as:		[RFC7975] for Recursive Request Redirection as:
	"The endpoint to which the User Agent is redirected. In CDNI, a		| The endpoint to which the User Agent is redirected. In CDNI, an
	RT may point to a number of different components, some examples		| RT may point to a number of different components, some examples
	include a surrogate in the same CDN as the request router, a		| include a surrogate in the same CDN as the request router, a
	request router in a dCDN, or a surrogate in a dCDN".		| request router in a dCDN, or a surrogate in a dCDN.
	In this document we adopt the same definition of the RT for the		In this document, we adopt the same definition of the RT for the
	Iterative Request Redirect use case. This use case requires the		Iterative Request Redirect use case. This use case requires the
	provisioning of the RT address to be used by the uCDN in order to		provisioning of the RT address to be used by the uCDN in order to
	redirect to the dCDN. RT addresses can vary between different		redirect to the dCDN. RT addresses can vary between different
	footprints, for example, between different regions, and they may also		footprints (for example, between different regions), and they may
	change over time, for example as a result of network problems. Given		also change over time (for example, as a result of network problems).
	this variable and dynamic nature of the redirect target address, it		Given this variable and dynamic nature of the redirect target
	may not be suitable to advertise it during bootstrap. A more dynamic		address, it may not be suitable to advertise it during bootstrap. A
	and footprint oriented interface is required. Section 4.3 of		more dynamic and footprint-oriented interface is required.
	[RFC7336] suggests that it could be one of the roles of the FCI		Section 4.3 of [RFC7336] suggests that it could be one of the roles
	[RFC8008]. Following this suggestion, we have therefore, chosen to		of the FCI [RFC8008]. Following this suggestion, we have therefore
	use the CDNI Footprint and Capabilities interface for redirect target		chosen to use the CDNI Footprint & Capabilities Advertisement
	address advertisement.		interface for redirect target address advertisement.
	Use cases		Use cases:
	o Footprint: The dCDN may want to have a different target per		* Footprint: The dCDN may want to have a different target per
	footprint. Note that a dCDN may spread across multiple		footprint. Note that a dCDN may spread across multiple
	geographies. This makes it easier to route client requests to a		geographies. This makes it easier to route client requests to a
	nearby request router. Though this can be achieved using a single		nearby request router. Though this can be achieved using a single
	canonical name and "Geo DNS", such that in different geographies		canonical name and "Geo DNS", such that in different geographies
	the same hostname is resolved to different IP address, that		the same hostname is resolved to different IP address, that
	approach has limitations; for example a client may be using a		approach has limitations; for example, a client may be using a
	third party DNS resolver, making it impossible for the redirector		third-party DNS resolver, making it impossible for the redirector
	to detect where the client is located, or Geo DNS granularity may		to detect where the client is located, or Geo DNS granularity may
	be too rough for the requirement of the application.		be too rough for the requirement of the application.
	o Scaling: The dCDN may choose to scale its request routing service		* Scaling: The dCDN may choose to scale its Request Routing service
	by deploying more request routers in new locations and advertise		by deploying more request routers in new locations and advertise
	them via an updatable interface like the FCI.		them via an updatable interface like the FCI.
	The Redirect Target capability object is used to indicate the target		The Redirect Target capability object is used to indicate the target
	address the uCDN should use in order to redirect a client to the		address the uCDN should use in order to redirect a client to the
	dCDN. A target may be attached to a specific uCDN host, a list of		dCDN. A target may be attached to a specific uCDN host, attached to
	uCDN hosts, or used globally for all the hosts of the uCDN.		a list of uCDN hosts, or used globally for all the hosts of the uCDN.
	When a dCDN is attaching the redirect target to a specific uCDN host		When a dCDN is attaching the redirect target to a specific uCDN host
	or a list of uCDN hosts, the dCDN MUST advertise the hosts within the		or a list of uCDN hosts, the dCDN MUST advertise the hosts within the
	Redirect Target capability object as "redirecting-hosts". In this		Redirect Target capability object as "redirecting-hosts". In this
	case, the uCDN can redirect to that dCDN address, only if the User		case, the uCDN can redirect to that dCDN address, only if the User
	Agent request was to one of these uCDN hosts.		Agent request was to one of these uCDN hosts.
	If the redirect target capability object does not contain a target or		If the Redirect Target capability object does not contain a target or
	the target is empty, the uCDN MUST interpret it as "no target		the target is empty, the uCDN MUST interpret it as "no target
	available for these uCDN hosts for the specified footprint". In case		available for these uCDN hosts for the specified footprint". In case
	such a target was already advertised in a previous FCI object, the		such a target was already advertised in a previous FCI object, the
	uCDN MUST interpret it as an update that deletes the previous		uCDN MUST interpret it as an update that deletes the previous
	redirect target.		redirect target.
	2.1. DNS Redirect Target		2.1. DNS Redirect Target
	A redirect target for DNS redirection is a FQDN used as an alias in a		A redirect target for DNS redirection is an FQDN used as an alias in
	CNAME record response (see [RFC1034]) of the uCDN DNS router. Note		a CNAME record response (see [RFC1034]) of the uCDN DNS router. Note
	that DNS routers make routing decisions based on either the DNS		that DNS routers make routing decisions based on either the DNS
	resolver's IP address or the client IP subnet when EDNS0 client-		resolver's IP address or the client IP subnet when EDNS0 client-
	subnet (ECS) is used (see [RFC7871]). The dCDN may choose to		subnet (ECS) is used (see [RFC7871]). The dCDN may choose to
	advertise redirect targets and footprints to cover both cases, such		advertise redirect targets and footprints to cover both cases, such
	that the uCDN resolution would route the DNS query to a different		that the uCDN resolution would route the DNS query to different dCDN
	dCDN CNAMEs according client subnet or dCDN resolver IP address.		CNAMEs according to client subnet or dCDN resolver IP address. This
	This method further allows the dCDN DNS to optimize the resolution by		method further allows the dCDN DNS to optimize the resolution by
	localizing the target CNAMEs. A uCDN implementation SHOULD prefer		localizing the target CNAMEs. A uCDN implementation SHOULD prefer
	routing based on client IP subnet when ECS option is present. A dCDN		routing based on client IP subnet when the ECS option is present. A
	implementation using the ECS option MUST be aware of the privacy		dCDN implementation using the ECS option MUST be aware of the privacy
	drawbacks listed in Section 2 of [RFC7871] and SHOULD follow the		drawbacks listed in Section 2 of [RFC7871] and SHOULD follow the
	guidelines provided in Section 11.1 of [RFC7871].		guidelines provided in Section 11.1 of [RFC7871].
	2.2. HTTP Redirect Target		2.2. HTTP Redirect Target
	A redirect target for HTTP redirection is the URI to be used as the		A redirect target for HTTP redirection is the URI to be used as the
	value for the Location header of a HTTP redirect 3xx response,		value for the Location header of an HTTP redirect 3xx response,
	typically a 302 (Found) (see Section 7.1.2 of [RFC7231] and section		typically a 302 (Found) (see Section 7.1.2 of [RFC7231] and
	6.4 of [RFC7231]).		Section 6.4 of [RFC7231]).
	2.3. Properties of Redirect Target Capability Object		2.3. Properties of Redirect Target Capability Object
	The Redirect Target capability object consists of the following		The Redirect Target capability object consists of the following
	properties:		properties:
	Property: redirecting-hosts		Property: redirecting-hosts
	Description: One or more uCDN hosts to which this redirect		Description: One or more uCDN hosts to which this redirect target
	target is attached. A redirecting host SHOULD be a host that		is attached. A redirecting host SHOULD be a host that was
	was published in a HostMatch object by the uCDN as defined in		published in a HostMatch object by the uCDN as defined in
	Section 4.1.2 of [RFC8006].		Section 4.1.2 of [RFC8006].
	Type: A list of Endpoint objects (see Section 4.3.3 of		Type: A list of Endpoint objects (see Section 4.3.3 of [RFC8006])
	[RFC8006])
	Mandatory-to-Specify: No. If not present, or empty, the		Mandatory-to-Specify: No. If absent or empty, the redirect
	redirect target applies to all hosts of the redirecting uCDN.		target applies to all hosts of the redirecting uCDN.
	Property: dns-target		Property: dns-target
	Description: Target CNAME record for DNS redirection.		Description:
			Target CNAME record for DNS redirection.
	Type: DnsTarget object (see Section 2.4)		Type:
			DnsTarget object (see Section 2.4)
	Mandatory-to-Specify: No. If the dns-target is not present or		Mandatory-to-Specify:
	empty the uCDN MUST interpret it as "no dns-target available".		No. If the dns-target is absent or empty, the uCDN MUST
			interpret it as "no dns-target available".
	Property: http-target		Property: http-target
	Description: Target URI for a HTTP redirect.		Description:
			Target URI for an HTTP redirect.
	Type: HttpTarget object (see Section 2.5)		Type:
			HttpTarget object (see Section 2.5)
	Mandatory-to-Specify: No. If the http-target is not present or		Mandatory-to-Specify:
	empty the uCDN MUST interpret it as "no http-target available".		No. If the http-target is absent or empty, the uCDN MUST
			interpret it as "no http-target available".
	The following is an example of a Redirect Target capability object		The following is an example of a Redirect Target capability object
	serialization that advertises a dCDN target address that is attached		serialization that advertises a dCDN target address that is attached
	to a specific list of uCDN "redirecting-hosts". A uCDN host that is		to a specific list of uCDN "redirecting-hosts". A uCDN host that is
	included in that list can redirect to the advertised dCDN redirect		included in that list can redirect to the advertised dCDN redirect
	target. The capabilities object is serialized as a JSON object as		target. The capabilities object is serialized as a JSON object as
	defined in Section 5.1 of [RFC8008]		defined in Section 5.1 of [RFC8008].
	{		{
	"capabilities": [		"capabilities": [
	{		{
	"capability-type": "FCI.RedirectTarget",		"capability-type": "FCI.RedirectTarget",
	"capability-value": {		"capability-value": {
	"redirecting-hosts": [		"redirecting-hosts": [
	"a.service123.ucdn.example.com",		"a.service123.ucdn.example.com",
	"b.service123.ucdn.example.com"		"b.service123.ucdn.example.com"
	],		],
	"dns-target": {		"dns-target": {
	skipping to change at page 7, line 34 ¶		skipping to change at line 309 ¶
	]		]
	}		}
	]		]
	}		}
	2.4. DnsTarget Object		2.4. DnsTarget Object
	The DnsTarget object gives the target address for the DNS response to		The DnsTarget object gives the target address for the DNS response to
	delegate from the uCDN to the dCDN.		delegate from the uCDN to the dCDN.
	Property: host		Property: host
	Description: The host property is a hostname or an IP address,		Description: The host property is a hostname or an IP address,
	without a port number.		without a port number.
	Type: Endpoint object as defined in Section 4.3.3 of [RFC8006]		Type: Endpoint object as defined in Section 4.3.3 of [RFC8006],
	with the limitation that it SHOULD NOT include a port number		with the limitation that it SHOULD NOT include a port number
	and, in case a port number is present, the uCDN MUST ignore it.		and, in case a port number is present, the uCDN MUST ignore it.
	Mandatory-to-Specify: Yes.		Mandatory-to-Specify: Yes.
	2.4.1. DNS Target Example		2.4.1. DnsTarget Example
	The following is an example of DnsTarget object:		The following is an example of the DnsTarget object:
	{		{
	"host": "service123.ucdn.dcdn.example.com"		"host": "service123.ucdn.dcdn.example.com"
	}		}
	The following is an example of a DNS query for uCDN address		The following is an example of a DNS query for uCDN address
	"a.service123.ucdn.example.com" and the corresponding CNAME		"a.service123.ucdn.example.com" and the corresponding CNAME
	redirection response:		redirection response:
	Query:		Query:
	a.service123.ucdn.example.com:		a.service123.ucdn.example.com:
	type A, class IN		type A, class IN
	Response:		Response:
	NAME: a.service123.ucdn.example.com, TYPE: CNAME, CLASS: IN,		NAME: a.service123.ucdn.example.com, TYPE: CNAME, CLASS: IN,
	TTL: 120, RDATA: service123.ucdn.dcdn.example.com		TTL: 120, RDATA: service123.ucdn.dcdn.example.com
	2.5. HttpTarget Object		2.5. HttpTarget Object
	The HttpTarget object gives the necessary information to construct		The HttpTarget object gives the necessary information to construct
	the target Location URI for HTTP redirection.		the target Location URI for HTTP redirection.
	Property: host		Property: host
	Description: Hostname or IP address and an optional port, i.e.,		Description: Hostname or IP address and an optional port, i.e.,
	the host and port of the authority component of the URI as		the host and port of the authority component of the URI as
	described in Section 3.2 of [RFC3986].		described in Section 3.2 of [RFC3986].
	Type: Endpoint object as defined in Section 4.3.3 of [RFC8006].		Type: Endpoint object as defined in Section 4.3.3 of [RFC8006].
	Mandatory-to-Specify: Yes.		Mandatory-to-Specify: Yes.
	Property: scheme		Property: scheme
	Description: A URI scheme to be used in the redirect response		Description: A URI scheme to be used in the redirect response
	location construction. When present, the uCDN MUST use the		location construction. When present, the uCDN MUST use the
	provided scheme in for HTTP redirection to the dCDN.		provided scheme in for HTTP redirection to the dCDN.
	Type: A URI scheme as defined in Section 3.1 of [RFC3986]		Type: A URI scheme as defined in Section 3.1 of [RFC3986],
	represented as a JSON string. The scheme MUST be either "http"		represented as a JSON string. The scheme MUST be either "http"
	or "https".		or "https".
	Mandatory-to-Specify: No. If this property is absent or empty		Mandatory-to-Specify: No. If this property is absent or empty,
	the uCDN request router MUST use the same scheme as was used in		the uCDN request router MUST use the same scheme as was used in
	the original request before redirection.		the original request before redirection.
	Property: path-prefix		Property: path-prefix
	Description: A path prefix for the HTTP redirect Location		Description: A path prefix for the HTTP redirect Location header.
	header. The original path is appended after this prefix.		The original path is appended after this prefix.
	Type: A prefix of a path-absolute as defined in Section 3.3 of		Type: A prefix of a path-absolute as defined in Section 3.3 of
	[RFC3986]. The prefix MUST end with a trailing slash, to		[RFC3986]. The prefix MUST end with a trailing slash to
	indicate the end of the last path segment in the prefix.		indicate the end of the last path segment in the prefix.
	Mandatory-to-Specify: No. If this property is absent or empty,		Mandatory-to-Specify: No. If this property is absent or empty,
	the uCDN MUST NOT prepend a path prefix to the original content		the uCDN MUST NOT prepend a path-prefix to the original content
	path, i.e., the original path MUST appear in the location URI		path, i.e., the original path MUST appear in the Location URI
	right after the authority component.		right after the authority component.
	Property: include-redirecting-host		Property: include-redirecting-host
	Description: A flag indicating whether or not to include the		Description: A flag indicating whether or not to include the
	redirecting host as the first path segment after the path-		redirecting host as the first path segment after the path-
	prefix. If set to true and a "path-prefix" is used, the uCDN		prefix. If set to true and a "path-prefix" is used, the uCDN
	redirecting host MUST be added as a separate path segment after		redirecting host MUST be added as a separate path segment after
	the path-prefix and before the original URL path. If set to		the path-prefix and before the original URL path. If set to
	true and there is no path-prefix, the uCDN redirecting host		true and there is no path-prefix, the uCDN redirecting host
	MUST be prepended as the first path segment in the redirect		MUST be prepended as the first path segment in the redirect
	URL.		URL.
	Type: Boolean.		Type: Boolean.
	Mandatory-to-Specify: No. Default value is False.		Mandatory-to-Specify: No. Default value is False.
	2.5.1. HTTP Target Example		2.5.1. HttpTarget Example
	Example of HttpTarget object with a "scheme", a "path-prefix", and		The following is an example of the HttpTarget object with a "scheme",
	"include-redirecting-host" properties:		a "path-prefix", and "include-redirecting-host" properties:
	{		{
	"host": "us-east1.dcdn.example.com",		"host": "us-east1.dcdn.example.com",
	"scheme": "https",		"scheme": "https",
	"path-prefix": "/cache/1/",		"path-prefix": "/cache/1/",
	"include-redirecting-host": true		"include-redirecting-host": true
	}		}
	Example of a HTTP request for content at uCDN host		The following is an example of an HTTP request for content at uCDN
	"a.service123.ucdn.example.com" and the corresponding HTTP response		host "a.service123.ucdn.example.com" and the corresponding HTTP
	with a Location header, used for redirecting the client to the dCDN,		response with a Location header, used for redirecting the client to
	constructed according to the HttpTarget object from the above		the dCDN, constructed according to the HttpTarget object from the
	example:		above example:
	Request:		Request:
	GET /vod/1/movie.mp4 HTTP/1.1		GET /vod/1/movie.mp4 HTTP/1.1
	Host: a.service123.ucdn.example.com		Host: a.service123.ucdn.example.com
	Response:		Response:
	HTTP/1.1 302 Found		HTTP/1.1 302 Found
	Location: https://us-east1.dcdn.example.com/cache/1/		Location: https://us-east1.dcdn.example.com/cache/1/
	a.service123.ucdn.example.com/vod/1/movie.mp4		a.service123.ucdn.example.com/vod/1/movie.mp4
	2.6. Usage Example		2.6. Usage Example
	Before requests can be routed from the uCDN to the dCDN the CDNs must		Before requests can be routed from the uCDN to the dCDN, the CDNs
	exchange service configurations between them. Using the MI, the uCDN		must exchange service configurations between them. Using the MI, the
	advertises out-of-band its hosts to the dCDN, each host is designated		uCDN advertises out-of-band its hosts to the dCDN; each host is
	by a hostname and has its own specific metadata (see Section 4.1.2 of		designated by a hostname and has its own specific metadata (see
	[RFC8006]. The dCDN, using the FCI, advertises, also out-of-band,		Section 4.1.2 of [RFC8006]). Using the FCI, the dCDN advertises
	the redirect target address object defined in Section 2.3 for the		(also out-of-band) the redirect target address defined in Section 2.3
	relevant uCDN hosts. The following is a generalized example of the		for the relevant uCDN hosts. The following is a generalized example
	message flow between an upstream CDN and a downstream dCDN. For		of the message flow between a uCDN and a dCDN. For simplicity, we
	simplicity, we focus on the sequence of messages between the uCDN and		focus on the sequence of messages between the uCDN and dCDN and not
	dCDN and not on how they are passed.		on how they are passed.
	dCDN uCDN		dCDN uCDN
	+ +		+ +
	| |		| |
	(1) | MI: host: s123.ucdn.example.com |		(1) | MI: host: s123.ucdn.example.com |
	| host-metadata: < metadata > |		| host-metadata: < metadata > |
	<-------------------------------------------------------+		<-------------------------------------------------------+
	| |		| |
	(2) | FCI: capability-type: FCI.RedirectTarget |		(2) | FCI: capability-type: FCI.RedirectTarget |
	| redirecting-hosts: s123.ucdn.example.com |		| redirecting-hosts: s123.ucdn.example.com |
	| target host: us-east1.dcdn.example.com |		| target host: us-east1.dcdn.example.com |
	+------------------------------------------------------->		+------------------------------------------------------->
	| |		| |
	| |		| |
	+ +		+ +
	Figure 1: Redirect target address advertisement		Figure 1: Redirect Target Address Advertisement
	1. The uCDN advertises a host (s123.ucdn.example.com) with the host		Explanation:
	metadata.
	2. The dCDN advertises its FCI objects to the uCDN including a		(1) The uCDN advertises a host (s123.ucdn.example.com) with the host
	FCI.RedirectTarget object that contains the redirect target		metadata.
	address (us-east1.dcdn.example.com) specified for that uCDN host.
			(2) The dCDN advertises its FCI objects to the uCDN, including a
			Redirect Target capability object that contains the redirect
			target address (us-east1.dcdn.example.com) specified for that
			uCDN host.
	Once the redirect target has been set, the uCDN can start redirecting		Once the redirect target has been set, the uCDN can start redirecting
	user requests to the dCDN. The following is a generic sequence of		user requests to the dCDN. The following is a generic sequence of
	redirection using the host and redirect target that were advertised		redirection using the host and redirect target that were advertised
	in Figure 1 above.		in Figure 1.
	End User dCDN uCDN RR		End User dCDN uCDN RR
	+ + +		+ + +
	| | |		| | |
	(1) | Request sent s123.ucdn.example.com |		(1) | Request sent s123.ucdn.example.com |
	+-----------------------+----------------------->		+-----------------------+----------------------->
	| | |		| | |
	(2) | Redirect to us-east1.dcdn.example.com |		(2) | Redirect to us-east1.dcdn.example.com |
	<-----------------------+-----------------------+		<-----------------------+-----------------------+
	| | |		| | |
	(3) | Request us-east1.dcdn.example.com |		(3) | Request us-east1.dcdn.example.com |
	+-----------------------> |		+-----------------------> |
	| | |		| | |
	(4) | Response | |		(4) | Response | |
	<-----------------------+ |		<-----------------------+ |
	| | |		| | |
	+ + +		+ + +
	Figure 2: Generic requests redirection sequence		Figure 2: Generic Request Redirection Sequence
	1. The End User sends a request (DNS or HTTP) to the uCDN Request		Explanation:
	Router (RR).
	2. Using the previously advertised Redirect Target, the uCDN		(1) The End User sends a request (DNS or HTTP) to the uCDN Request
	redirects the request to the dCDN.		Router (RR).
	3. The End User sends a request to the dCDN.		(2) Using the previously advertised Redirect Target, the uCDN
			redirects the request to the dCDN.
	4. The dCDN either sends a response or reroutes it, for example, to		(3) The End User sends a request to the dCDN.
	a dCDN surrogate.
	3. Fallback Target Address Metadata		(4) The dCDN either sends a response or reroutes it, for example, to
			a dCDN surrogate.
			3. Fallback Target Server Address
	Open Caching requires that the uCDN provides a fallback target server		Open Caching requires that the uCDN provides a fallback target server
	to the dCDN, to be used in cases where the dCDN cannot properly		to the dCDN to be used in cases where the dCDN cannot properly handle
	handle the request. To avoid redirect loops, the fallback target		the request. To avoid redirect loops, the fallback target server's
	server's address at the uCDN MUST be different from the original uCDN		address at the uCDN MUST be different from the original uCDN address
	address from which the client was redirected to the dCDN. The uCDN		from which the client was redirected to the dCDN. The uCDN MUST
	MUST avoid further redirection when receiving the client request at		avoid further redirection when receiving the client request at the
	the fallback target. The fallback target is defined as a generic		fallback target. The Fallback Target is defined as a generic
	metadata object (see Section 3.2 of [RFC8006])		metadata object (see Section 3.2 of [RFC8006]).
	Use cases		Use cases:
	o Failover: A dCDN request router receives a request but has no
			* Failover: A dCDN request router receives a request but has no
	caches to which it can route the request. This can happen in the		caches to which it can route the request. This can happen in the
	case of failures or temporary network overload.		case of failures or temporary network overload.
	o No coverage: A dCDN request router receives a request from a		* No coverage: A dCDN request router receives a request from a
	client located in an area inside the footprint but not covered by		client located in an area inside the footprint but not covered by
	the dCDN caches or outside the dCDN footprint coverage. In such		the dCDN caches or outside the dCDN footprint coverage. In such
	cases, the router may choose to redirect the request back to the		cases, the router may choose to redirect the request back to the
	uCDN fallback address.		uCDN fallback address.
	o Error: A cache may receive a request that it cannot properly		* Error: A cache may receive a request that it cannot properly
	serve, for example, some of the metadata objects for that service		serve, for example, some of the metadata objects for that service
	were not properly acquired. In this case, the cache's "default		were not properly acquired. In this case, the cache's "default
	action" may be to "redirect back to uCDN".		action" may be to "redirect back to uCDN".
	The Fallback target metadata object is used to indicate the target		The Fallback Target metadata object is used to indicate the target
	address the dCDN should redirect a client to when falling back to the		address the dCDN should redirect a client to when falling back to the
	uCDN. Fallback target address is represented as an endpoint object		uCDN. The fallback target address is represented as an Endpoint
	as defined in Section 4.3.3 of [RFC8006].		object as defined in Section 4.3.3 of [RFC8006].
	In DNS redirection a CNAME record is used as the fallback target		In DNS redirection, a CNAME record is used as the fallback target
	address.		address.
	In HTTP redirection a hostname is used as the fallback target		In HTTP redirection, a hostname is used as the fallback target
	address.		address.
	When using HTTP redirect to route a client request back to the uCDN,		When using HTTP redirect to route a client request back to the uCDN,
	it is the dCDN's responsibility to use the original URL path as the		it is the dCDN's responsibility to use the original URL path as the
	client would have used for the original uCDN request, stripping, if		client would have used for the original uCDN request, stripping, if
	needed, the dCDN path-prefix and/or the uCDN hostname from the		needed, the dCDN path-prefix and/or the uCDN hostname from the
	redirect URL that may have been used to request the content from the		redirect URL that may have been used to request the content from the
	dCDN.		dCDN.
	3.1. Properties of Fallback Target Address Metadata Object		3.1. Properties of Fallback Target Generic Metadata Object
	The MI.FallbackTarget Metadata object consists of the following		The MI.FallbackTarget generic metadata object consists of the
	single property:		following two properties:
	Property: host		Property: host
	Description: Target address to which the dCDN can redirect the		Description: Target address to which the dCDN can redirect the
	client.		client.
	Type: Endpoint object as defined in Section 4.3.3 of [RFC8006]		Type: Endpoint object as defined in Section 4.3.3 of [RFC8006],
	with the limitation that in case of DNS delegation it SHOULD		with the limitation that in case of DNS delegation, it SHOULD
	NOT include a port number and, in case a port number is		NOT include a port number, and in case a port number is
	present, the dCDN MUST ignore it.		present, the dCDN MUST ignore it.
	Mandatory-to-Specify: Yes.		Mandatory-to-Specify: Yes.
	Property: scheme		Property: scheme
	Description: A URI scheme to be used in the redirect response		Description: A URI scheme to be used in the redirect response
	location construction. When present, the dCDN MUST use this		location construction. When present, the dCDN MUST use this
	scheme in case of HTTP redirection to the uCDN fallback		scheme in case of HTTP redirection to the uCDN fallback
	address.		address.
	Type: A URI scheme as defined in Section 3.1 of [RFC3986]		Type: A URI scheme as defined in Section 3.1 of [RFC3986],
	represented as a JSON string. The scheme MUST be either "http"		represented as a JSON string. The scheme MUST be either "http"
	or "https".		or "https".
	Mandatory-to-Specify: No. In case of HTTP redirection to		Mandatory-to-Specify: No. In case of HTTP redirection to
	fallback, if this property is absent or empty, the dCDN		fallback, if this property is absent or empty, the dCDN
	redirecting entity MUST use the same scheme as in the request		redirecting entity MUST use the same scheme as in the request
	received by the dCDN.		received by the dCDN.
	Example of a MI.FallbackTarget Metadata object that designates the		The following is an example of an MI.FallbackTarget generic metadata
	host address the dCDN should use as fallback address to redirect back		object that designates the host address the dCDN should use as
	to the uCDN.		fallback address to redirect back to the uCDN:
	{		{
	"generic-metadata-type": "MI.FallbackTarget",		"generic-metadata-type": "MI.FallbackTarget",
	"generic-metadata-value":		"generic-metadata-value":
	{		{
	"host": "fallback-a.service123.ucdn.example",		"host": "fallback-a.service123.ucdn.example",
	"scheme": "https"		"scheme": "https"
	}		}
	}		}
	3.2. Usage Example		3.2. Usage Example
	The uCDN advertises out-of-band the fallback target address to the		The uCDN advertises out-of-band the fallback target address to the
	dCDN, so that the dCDN may redirect a request back to the uCDN in		dCDN, so that the dCDN may redirect a request back to the uCDN in
	case the dCDN cannot serve it. Using the MI the uCDN advertises its		case the dCDN cannot serve it. Using the MI, the uCDN advertises its
	hosts to the dCDN, along with their specific host metadata (see		hosts to the dCDN, along with their specific host metadata (see
	Section 4.1.2 of [RFC8006]. The Fallback Target generic metadata		Section 4.1.2 of [RFC8006]). The Fallback Target generic metadata
	object is encapsulated within the "host-metadata" property of each		object is encapsulated within the "host-metadata" property of each
	host. The following is an example of a message flow between an		host. The following is an example of a message flow between a uCDN
	upstream CDN and a downstream dCDN. For simplicity, we focus on the		and a dCDN. For simplicity, we focus on the sequence of messages
	sequence of messages between the uCDN and dCDN, not on how they are		between the uCDN and dCDN, not on how they are passed.
	passed.
	dCDN uCDN		dCDN uCDN
	+ +		+ +
	| |		| |
	(1) | MI: host: s123.ucdn.example.com |		(1) | MI: host: s123.ucdn.example.com |
	| host-metadata: |		| host-metadata: |
	| < metadata objects > |		| < metadata objects > |
	| < MI.FallbackTarget |		| < MI.FallbackTarget |
	| host: fallback-a.service123.ucdn.example > |		| host: fallback-a.service123.ucdn.example > |
	| < metadata objects > |		| < metadata objects > |
	<-------------------------------------------------------+		<-------------------------------------------------------+
	| |		| |
	(2) | FCI: capability-type: FCI.RedirectTarget |		(2) | FCI: capability-type: FCI.RedirectTarget |
	| redirecting-hosts: s123.ucdn.example.com |		| redirecting-hosts: s123.ucdn.example.com |
	| target host: us-east1.dcdn.example.com |		| target host: us-east1.dcdn.example.com |
	+------------------------------------------------------->		+------------------------------------------------------->
	| |		| |
	| |		| |
	+ +		+ +
	Figure 3: Advertisement of host metadata with Fallback Target		Figure 3: Advertisement of Host Metadata with Fallback Target
	1. The uCDN advertises a host (s123.ucdn.example.com) with the host		Explanation:
	metadata. The host-metadata property contains a
	MI.FallbackTarget object.
	2. The dCDN advertises its FCI objects to the uCDN including a		(1) The uCDN advertises a host (s123.ucdn.example.com) with the host
	FCI.RedirectTarget object that contains the redirect target		metadata. The host-metadata property contains an
	address (us-east1.dcdn.example.com) specified for that uCDN host.		MI.FallbackTarget generic metadata object.
			(2) The dCDN advertises its FCI objects to the uCDN, including a
			Redirect Target capability object that contains the redirect
			target address (us-east1.dcdn.example.com) specified for that
			uCDN host.
	The following is a generic sequence of redirection using the		The following is a generic sequence of redirection using the
	configurations that were advertised in Figure 3 above. In this case		configurations that were advertised in Figure 3. In this case, the
	the dCDN redirects back to the uCDN fallback target address.		dCDN redirects back to the uCDN fallback target address.
	End User dCDN uCDN fallback uCDN RR		End User dCDN uCDN fallback uCDN RR
	+ + + +		+ + + +
	| | | |		| | | |
	(1) | Request sent s123.ucdn.example.com | |		(1) | Request sent s123.ucdn.example.com | |
	+-------------------+-------------------+------------------->		+-------------------+-------------------+------------------->
	| | | |		| | | |
	(2) | Redirect to us-east1.dcdn.example.com | |		(2) | Redirect to us-east1.dcdn.example.com | |
	<-------------------+-------------------+-------------------+		<-------------------+-------------------+-------------------+
	| | | |		| | | |
	skipping to change at page 15, line 28 ¶		skipping to change at line 665 ¶
	<-------------------+ | |		<-------------------+ | |
	| | | |		| | | |
	(5) | Request fallback-a.service123.ucdn.example |		(5) | Request fallback-a.service123.ucdn.example |
	+---------------------------------------> |		+---------------------------------------> |
	| | | |		| | | |
	(6) | Response | | |		(6) | Response | | |
	<-------------------+-------------------+ |		<-------------------+-------------------+ |
	| | | |		| | | |
	+ + + +		+ + + +
	Figure 4: Redirection to Fallback Target		Figure 4: Redirection to Fallback Target
	1. The End User sends a request (DNS or HTTP) to the uCDN Request		Explanation:
	Router (RR).
	2. Using the previously advertised Redirect Target, the uCDN		(1) The End User sends a request (DNS or HTTP) to the uCDN Request
	redirects the request to the dCDN.		Router (RR).
	3. The End User sends a request to the dCDN.		(2) Using the previously advertised Redirect Target, the uCDN
			redirects the request to the dCDN.
	4. The dCDN cannot handled the request and, therefore, redirects it		(3) The End User sends a request to the dCDN.
	back to the uCDN fallback target address.
	5. The End User sends the request to the uCDN fallback target		(4) The dCDN cannot handle the request and therefore redirects it
	address.		back to the uCDN fallback target address.
	6. The uCDN either sends a response or reroutes it, for example, to		(5) The End User sends the request to the uCDN fallback target
	a uCDN surrogate.		address.
	3.3. uCDN addressing considerations		(6) The uCDN either sends a response or reroutes it, for example, to
			a uCDN surrogate.
	When advertising fallback addresses to the dCDN the uCDN SHOULD		3.3. uCDN Addressing Considerations
			When advertising fallback addresses to the dCDN, the uCDN SHOULD
	consider the failure use cases that may lead the dCDN to route		consider the failure use cases that may lead the dCDN to route
	requests to uCDN fallback. In extreme dCDN network failures or under		requests to uCDN fallback. In extreme dCDN network failures or under
	denial-of-service (DoS) attacks, requests coming from a large segment		denial-of-service (DoS) attacks, requests coming from a large segment
	or multiple segments of the dCDN may be routed back to the uCDN. The		or multiple segments of the dCDN may be routed back to the uCDN. The
	uCDN SHOULD therefore design its fallback addressing scheme and its		uCDN SHOULD therefore design its fallback addressing scheme and its
	available resources accordingly. A favorable approach would be for		available resources accordingly. A favorable approach would be for
	the uCDN to use different fallback target address for each uCDN host,		the uCDN to use a different fallback target address for each uCDN
	enabling it to load balance the requests using the same methods as it		host, enabling it to load balance the requests using the same methods
	would for its original hosts. See Sections 4.1.2 and 4.1.3 of		as it would for its original hosts. See Sections 4.1.2 and 4.1.3 of
	[RFC8006] for a detailed description of how to use GenericMetadata		[RFC8006] for a detailed description of how to use GenericMetadata
	objects within the HostMatch object advertised in the HostIndex of		objects within the HostMatch object advertised in the HostIndex of
	the uCDN.		the uCDN.
	4. IANA Considerations		4. IANA Considerations
	4.1. CDNI Payload Types		4.1. CDNI Payload Types
	This document requests the registration of the following CDNI Payload		IANA has registered the following CDNI Payload Types in the "CDNI
	Types under the IANA "CDNI Payload Types" registry defined in		Payload Types" registry defined in [RFC7736]:
	[RFC7736]:
	+--------------------+---------------+		+====================+===============+
	| Payload Type | Specification |		| Payload Type | Specification |
			+====================+===============+
			| FCI.RedirectTarget | RFC 8804 |
	+--------------------+---------------+		+--------------------+---------------+
	| FCI.RedirectTarget | RFCthis |		| MI.FallbackTarget | RFC 8804 |
	| MI.FallbackTarget | RFCthis |
	+--------------------+---------------+		+--------------------+---------------+
	[RFC Editor: Please replace RFCthis with the published RFC number for		Table 1
	this document.]
	4.1.1. CDNI FCI RedirectTarget Payload Type		4.1.1. CDNI FCI RedirectTarget Payload Type
	Purpose: The purpose of this payload type is to distinguish		Purpose: The purpose of this payload type is to distinguish FCI
	RedirectTarget FCI objects		advertisement objects for redirect target.
	Interface: FCI		Interface: FCI
	Encoding: see Section 2.3		Encoding: See Section 2.3.
	4.1.2. CDNI MI FallbackTarget Payload Type		4.1.2. CDNI MI FallbackTarget Payload Type
	Purpose: The purpose of this payload type is to distinguish		Purpose: The purpose of this payload type is to distinguish
	FallbackTarget MI objects (and any associated capability		FallbackTarget MI objects (and any associated capability
	advertisement)		advertisement).
	Interface: MI/FCI		Interface: MI/FCI
	Encoding: see Section 3.1		Encoding: See Section 3.1.
	5. Security Considerations		5. Security Considerations
	This specification is in accordance with the CDNI Metadata Interface		This specification defines extensions to the CDNI Metadata Interface
	and the CDNI Request Routing: Footprint and Capabilities Semantics.		(MI) and the Footprint & Capabilities Advertisement interface (FCI).
	As such, it is subject to the security and privacy considerations as		As such, it is subject to the security and privacy considerations
	defined in Section 8 of [RFC8006] and in Section 7 of [RFC8008]		defined in Section 8 of [RFC8006] and in Section 7 of [RFC8008],
	respectively.		respectively.
	5.1. Confidentiality and Privacy		5.1. Confidentiality and Privacy
	The Redirect Target FCI object potentially reveals information about		The Redirect Target capability object potentially reveals information
	the internal structure of the dCDN network. A third party could		about the internal structure of the dCDN network. A third party
	intercept the FCI transactions and use the information to attack the		could intercept the FCI transactions and use the information to
	dCDN. The same is also true for the Fallback Target Metadata object		attack the dCDN. The same is also true for the Fallback Target
	as it may reveal information about the internal structure of the		generic metadata object, as it may reveal information about the
	uCDN, exposing it to external exploits. Implementations of the FCI		internal structure of the uCDN, exposing it to external exploits.
	and MI MUST therefore use strong authentication and encryption and		Implementations of the FCI and MI MUST therefore use strong
	strictly follow the directions for securing the interface as defined		authentication and encryption and strictly follow the directions for
	for the Metadata Interface in Section 8.3 of [RFC8006].		securing the interface as defined for the Metadata Interface in
			Section 8.3 of [RFC8006].
	6. Acknowledgements
	The authors thank Nir B. Sopher for reality checks against production
	use cases, his contribution is significant to this document. The
	authors also thank Ben Niven-Jenkins for his review and feedback and
	Kevin J. Ma for his guidance throughout the development of this
	document including his regular reviews.
	7. References		6. References
	7.1. Normative References		6.1. Normative References
	[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",		[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
	STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,		STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
	<https://www.rfc-editor.org/info/rfc1034>.		<https://www.rfc-editor.org/info/rfc1034>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	skipping to change at page 18, line 46 ¶		skipping to change at line 818 ¶
	[RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,		[RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
	R., and K. Ma, "Content Delivery Network Interconnection		R., and K. Ma, "Content Delivery Network Interconnection
	(CDNI) Request Routing: Footprint and Capabilities		(CDNI) Request Routing: Footprint and Capabilities
	Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,		Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
	<https://www.rfc-editor.org/info/rfc8008>.		<https://www.rfc-editor.org/info/rfc8008>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	7.2. Informative References		6.2. Informative References
	[OC-RR] Finkelman, O., Ed., Hofmann, J., Klein, E., Mishra, S.,		[OC-RR] Finkelman, O., Ed., Hofmann, J., Klein, E., Mishra, S.,
	Ma, K., Sahar, D., and B. Zurat, "Open Caching - Request		Ma, K., Sahar, D., and B. Zurat, "Open Cache Request
	Routing Functional Specification", Version 1.1, October		Routing Functional Specification", Version 1.1, November
	2019, <https://www.streamingvideoalliance.org/books/open-		2016, <https://www.streamingvideoalliance.org/books/open-
	cache-request-routing-functional-specification/>.		cache-request-routing-functional-specification/>.
	[OCWG] "Open Caching Home Page",		[OCWG] Streaming Video Alliance, "Open Caching",
	<https://www.streamingvideoalliance.org/technical-groups/		<https://www.streamingvideoalliance.org/technical-groups/
	open-caching/>.		open-caching/>.
	[RFC7736] Ma, K., "Content Delivery Network Interconnection (CDNI)		[RFC7736] Ma, K., "Content Delivery Network Interconnection (CDNI)
	Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,		Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
	December 2015, <https://www.rfc-editor.org/info/rfc7736>.		December 2015, <https://www.rfc-editor.org/info/rfc7736>.
	[RFC7871] Contavalli, C., van der Gaast, W., Lawrence, D., and W.		[RFC7871] Contavalli, C., van der Gaast, W., Lawrence, D., and W.
	Kumari, "Client Subnet in DNS Queries", RFC 7871,		Kumari, "Client Subnet in DNS Queries", RFC 7871,
	DOI 10.17487/RFC7871, May 2016,		DOI 10.17487/RFC7871, May 2016,
	<https://www.rfc-editor.org/info/rfc7871>.		<https://www.rfc-editor.org/info/rfc7871>.
	[SVA] "Streaming Video Alliance Home Page",		[SVA] "Streaming Video Alliance",
	<https://www.streamingvideoalliance.org>.		<https://www.streamingvideoalliance.org>.
			Acknowledgements
			The authors thank Nir B. Sopher for reality checks against production
			use cases; his contribution is significant to this document. The
			authors also thank Ben Niven-Jenkins for his review and feedback and
			Kevin J. Ma for his guidance throughout the development of this
			document, including his regular reviews.
	Authors' Addresses		Authors' Addresses
	Ori Finkelman		Ori Finkelman
	Qwilt		Qwilt
	6, Ha'harash		6, Ha'harash
	Hod HaSharon 4524079		Hod HaSharon 4524079
	Israel		Israel
	Email: ori.finkelman.ietf@gmail.com		Email: ori.finkelman.ietf@gmail.com
	Sanjay Mishra		Sanjay Mishra
	Verizon		Verizon
	13100 Columbia Pike		13100 Columbia Pike
	Silver Spring, MD 20904		Silver Spring, MD 20904
	USA		United States of America
	Email: sanjay.mishra@verizon.com		Email: sanjay.mishra@verizon.com
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