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
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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.
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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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