draft-ietf-cdni-metadata-10.txt   draft-ietf-cdni-metadata-11.txt 
Network Working Group B. Niven-Jenkins Network Working Group B. Niven-Jenkins
Internet-Draft R. Murray Internet-Draft R. Murray
Intended status: Standards Track Velocix (Alcatel-Lucent) Intended status: Standards Track Velocix (Alcatel-Lucent)
Expires: January 7, 2016 M. Caulfield Expires: January 28, 2016 M. Caulfield
Cisco Systems Cisco Systems
K. Ma K. Ma
Ericsson Ericsson
July 6, 2015 July 27, 2015
CDN Interconnection Metadata CDN Interconnection Metadata
draft-ietf-cdni-metadata-10 draft-ietf-cdni-metadata-11
Abstract Abstract
The Content Delivery Networks Interconnection (CDNI) Metadata The Content Delivery Networks Interconnection (CDNI) metadata
interface enables interconnected Content Delivery Networks (CDNs) to interface enables interconnected Content Delivery Networks (CDNs) to
exchange content distribution metadata in order to enable content exchange content distribution metadata in order to enable content
acquisition and delivery. The CDNI metadata associated with a piece acquisition and delivery. The CDNI metadata associated with a piece
of content provides a downstream CDN with sufficient information for of content provides a downstream CDN with sufficient information for
the downstream CDN to service content requests on behalf of an the downstream CDN to service content requests on behalf of an
upstream CDN. This document describes both a base set of CDNI upstream CDN. This document describes both a base set of CDNI
metadata and the protocol for exchanging that metadata. metadata and the protocol for exchanging that metadata.
Requirements Language Requirements Language
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 7, 2016. This Internet-Draft will expire on January 28, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Supported Metadata Capabilities . . . . . . . . . . . . . 5 1.2. Supported Metadata Capabilities . . . . . . . . . . . . . 5
2. Design Principles . . . . . . . . . . . . . . . . . . . . . . 6 2. Design Principles . . . . . . . . . . . . . . . . . . . . . . 6
3. CDNI Metadata model . . . . . . . . . . . . . . . . . . . . . 7 3. CDNI Metadata object model . . . . . . . . . . . . . . . . . 6
3.1. HostIndex, HostMatch, HostMetadata, PathMatch, 3.1. HostIndex, HostMatch, HostMetadata, PathMatch,
PatternMatch and PathMetadata objects . . . . . . . . . . 8 PatternMatch and PathMetadata objects . . . . . . . . . . 8
3.2. Generic CDNI Metadata Object Properties . . . . . . . . . 10 3.2. Generic CDNI Metadata Objects . . . . . . . . . . . . . . 10
3.3. Metadata Inheritance and Override . . . . . . . . . . . . 13 3.3. Metadata Inheritance and Override . . . . . . . . . . . . 13
4. CDNI Metadata objects . . . . . . . . . . . . . . . . . . . . 14 4. CDNI Metadata objects . . . . . . . . . . . . . . . . . . . . 14
4.1. Definitions of the CDNI structural metadata objects . . . 15 4.1. Definitions of the CDNI structural metadata objects . . . 15
4.1.1. HostIndex . . . . . . . . . . . . . . . . . . . . . . 15 4.1.1. HostIndex . . . . . . . . . . . . . . . . . . . . . . 15
4.1.2. HostMatch . . . . . . . . . . . . . . . . . . . . . . 16 4.1.2. HostMatch . . . . . . . . . . . . . . . . . . . . . . 16
4.1.3. HostMetadata . . . . . . . . . . . . . . . . . . . . 17 4.1.3. HostMetadata . . . . . . . . . . . . . . . . . . . . 17
4.1.4. PathMatch . . . . . . . . . . . . . . . . . . . . . . 18 4.1.4. PathMatch . . . . . . . . . . . . . . . . . . . . . . 18
4.1.5. PatternMatch . . . . . . . . . . . . . . . . . . . . 19 4.1.5. PatternMatch . . . . . . . . . . . . . . . . . . . . 19
4.1.6. PathMetadata . . . . . . . . . . . . . . . . . . . . 20 4.1.6. PathMetadata . . . . . . . . . . . . . . . . . . . . 20
4.1.7. GenericMetadata . . . . . . . . . . . . . . . . . . . 21 4.1.7. GenericMetadata . . . . . . . . . . . . . . . . . . . 21
4.2. Definitions of the initial set of CDNI Generic Metadata 4.2. Definitions of the initial set of CDNI Generic Metadata
objects . . . . . . . . . . . . . . . . . . . . . . . . . 23 objects . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.1. SourceMetadata . . . . . . . . . . . . . . . . . . . 23 4.2.1. SourceMetadata . . . . . . . . . . . . . . . . . . . 23
4.2.1.1. Source . . . . . . . . . . . . . . . . . . . . . 24 4.2.1.1. Source . . . . . . . . . . . . . . . . . . . . . 24
4.2.2. LocationACL Metadata . . . . . . . . . . . . . . . . 25 4.2.2. LocationACL Metadata . . . . . . . . . . . . . . . . 25
4.2.2.1. LocationRule . . . . . . . . . . . . . . . . . . 27 4.2.2.1. LocationRule . . . . . . . . . . . . . . . . . . 27
4.2.2.2. Footprint . . . . . . . . . . . . . . . . . . . . 28 4.2.2.2. Footprint . . . . . . . . . . . . . . . . . . . . 28
4.2.3. TimeWindowACL Metadata . . . . . . . . . . . . . . . 28 4.2.3. TimeWindowACL . . . . . . . . . . . . . . . . . . . . 29
4.2.3.1. TimeWindowRule . . . . . . . . . . . . . . . . . 29 4.2.3.1. TimeWindowRule . . . . . . . . . . . . . . . . . 31
4.2.3.2. TimeWindow . . . . . . . . . . . . . . . . . . . 29 4.2.3.2. TimeWindow . . . . . . . . . . . . . . . . . . . 32
4.2.4. ProtocolACL Metadata . . . . . . . . . . . . . . . . 30 4.2.4. ProtocolACL Metadata . . . . . . . . . . . . . . . . 32
4.2.4.1. ProtocolRule . . . . . . . . . . . . . . . . . . 30 4.2.4.1. ProtocolRule . . . . . . . . . . . . . . . . . . 33
4.2.5. DeliveryAuthorization Metadata . . . . . . . . . . . 31 4.2.5. DeliveryAuthorization Metadata . . . . . . . . . . . 34
4.2.6. Cache . . . . . . . . . . . . . . . . . . . . . . . . 31 4.2.6. Cache . . . . . . . . . . . . . . . . . . . . . . . . 34
4.2.7. Grouping . . . . . . . . . . . . . . . . . . . . . . 32 4.2.7. Auth . . . . . . . . . . . . . . . . . . . . . . . . 35
4.3. CDNI Metadata Simple Data Type Descriptions . . . . . . . 32 4.2.7.1. BasicAuth . . . . . . . . . . . . . . . . . . . . 36
4.3.1. Link . . . . . . . . . . . . . . . . . . . . . . . . 32 4.2.8. Grouping . . . . . . . . . . . . . . . . . . . . . . 37
4.3.2. Protocol . . . . . . . . . . . . . . . . . . . . . . 33 4.3. CDNI Metadata Simple Data Type Descriptions . . . . . . . 38
4.3.3. Endpoint . . . . . . . . . . . . . . . . . . . . . . 33 4.3.1. Link . . . . . . . . . . . . . . . . . . . . . . . . 38
4.3.4. URI . . . . . . . . . . . . . . . . . . . . . . . . . 33 4.3.2. Protocol . . . . . . . . . . . . . . . . . . . . . . 39
4.3.5. Time . . . . . . . . . . . . . . . . . . . . . . . . 33 4.3.3. Endpoint . . . . . . . . . . . . . . . . . . . . . . 39
4.3.6. Auth . . . . . . . . . . . . . . . . . . . . . . . . 33 4.3.4. Time . . . . . . . . . . . . . . . . . . . . . . . . 40
4.3.6.1. CredentialAuth Type . . . . . . . . . . . . . . . 34 4.3.5. IPv4CIDR . . . . . . . . . . . . . . . . . . . . . . 40
4.3.7. IPv4CIDR . . . . . . . . . . . . . . . . . . . . . . 34 4.3.6. IPv6CIDR . . . . . . . . . . . . . . . . . . . . . . 40
4.3.8. IPv6CIDR . . . . . . . . . . . . . . . . . . . . . . 35 4.3.7. ASN . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.3.9. ASN . . . . . . . . . . . . . . . . . . . . . . . . . 35 4.3.8. CountryCode . . . . . . . . . . . . . . . . . . . . . 41
4.3.10. CountryCode . . . . . . . . . . . . . . . . . . . . . 35 5. CDNI Metadata Capabilities . . . . . . . . . . . . . . . . . 41
5. CDNI Metadata Capabilities . . . . . . . . . . . . . . . . . 35 6. CDNI Metadata interface . . . . . . . . . . . . . . . . . . . 41
6. CDNI Metadata interface . . . . . . . . . . . . . . . . . . . 36 6.1. Transport . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1. Transport . . . . . . . . . . . . . . . . . . . . . . . . 36 6.2. Retrieval of CDNI Metadata resources . . . . . . . . . . 43
6.2. Retrieval of CDNI Metadata resources . . . . . . . . . . 37 6.3. Bootstrapping . . . . . . . . . . . . . . . . . . . . . . 44
6.3. Bootstrapping . . . . . . . . . . . . . . . . . . . . . . 38 6.4. Encoding . . . . . . . . . . . . . . . . . . . . . . . . 44
6.4. Encoding . . . . . . . . . . . . . . . . . . . . . . . . 39
6.4.1. MIME Media Types . . . . . . . . . . . . . . . . . . 39
6.4.2. I-JSON Encoding of Objects . . . . . . . . . . . . . 40
6.4.2.1. Encoded CDNI Metadata Example . . . . . . . . . . 41
6.5. Extensibility . . . . . . . . . . . . . . . . . . . . . . 45 6.5. Extensibility . . . . . . . . . . . . . . . . . . . . . . 45
6.6. Metadata Enforcement . . . . . . . . . . . . . . . . . . 46 6.6. Metadata Enforcement . . . . . . . . . . . . . . . . . . 46
6.7. Metadata Conflicts . . . . . . . . . . . . . . . . . . . 46 6.7. Metadata Conflicts . . . . . . . . . . . . . . . . . . . 46
6.8. Versioning . . . . . . . . . . . . . . . . . . . . . . . 47 6.8. Versioning . . . . . . . . . . . . . . . . . . . . . . . 47
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 47 6.9. Media Types . . . . . . . . . . . . . . . . . . . . . . . 47
7.1. CDNI Metadata Footprint Types Registry . . . . . . . . . 48 6.10. Complete CDNI Metadata Example . . . . . . . . . . . . . 48
7.2. CDNI Metadata Protocol Types Registry . . . . . . . . . . 49 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52
7.3. CDNI Metadata Auth Types Registry . . . . . . . . . . . . 49 7.1. CDNI Metadata Footprint Types Registry . . . . . . . . . 53
8. Security Considerations . . . . . . . . . . . . . . . . . . . 50 7.2. CDNI Metadata Protocol Types Registry . . . . . . . . . . 54
8.1. Authentication . . . . . . . . . . . . . . . . . . . . . 50 7.3. CDNI Metadata Auth Types Registry . . . . . . . . . . . . 54
8.2. Confidentiality . . . . . . . . . . . . . . . . . . . . . 51 8. Security Considerations . . . . . . . . . . . . . . . . . . . 54
8.3. Integrity . . . . . . . . . . . . . . . . . . . . . . . . 51 8.1. Authentication . . . . . . . . . . . . . . . . . . . . . 55
8.4. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 51 8.2. Confidentiality . . . . . . . . . . . . . . . . . . . . . 55
8.5. Securing the CDNI Metadata interface . . . . . . . . . . 51 8.3. Integrity . . . . . . . . . . . . . . . . . . . . . . . . 55
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 52 8.4. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 56
10. Contributing Authors . . . . . . . . . . . . . . . . . . . . 52 8.5. Securing the CDNI Metadata interface . . . . . . . . . . 56
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 53 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 57
11.1. Normative References . . . . . . . . . . . . . . . . . . 53 10. Contributing Authors . . . . . . . . . . . . . . . . . . . . 57
11.2. Informative References . . . . . . . . . . . . . . . . . 53 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 57
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 54 11.1. Normative References . . . . . . . . . . . . . . . . . . 57
11.2. Informative References . . . . . . . . . . . . . . . . . 58
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 59
1. Introduction 1. Introduction
Content Delivery Networks Interconnection (CDNI) ([RFC6707]) enables Content Delivery Networks Interconnection (CDNI) [RFC6707] enables a
a downstream Content Delivery Network (dCDN) to service content downstream Content Delivery Network (dCDN) to service content
requests on behalf of an upstream CDN (uCDN). requests on behalf of an upstream CDN (uCDN).
The CDNI Metadata interface is discussed in [RFC7336] along with four The CDNI metadata interface is discussed in [RFC7336] along with four
other interfaces that may be used to compose a CDNI solution (CDNI other interfaces that may be used to compose a CDNI solution (CDNI
Control interface, CDNI Request Routing Redirection interface, CDNI Control interface, CDNI Request Routing Redirection interface, CDNI
Footprint & Capabilities Advertisement interface and CDNI Logging Footprint & Capabilities Advertisement interface and CDNI Logging
interface). [RFC7336] describes each interface, and the interface). [RFC7336] describes each interface, and the
relationships between them. The requirements for the CDNI metadata relationships between them. The requirements for the CDNI metadata
interface are specified in [RFC7337]. interface are specified in [RFC7337].
The CDNI metadata associated with a piece of content (or with a set The CDNI metadata associated with a piece of content (or with a set
of content) provides a dCDN with sufficient information for servicing of content) provides a dCDN with sufficient information for servicing
content requests on behalf of an uCDN in accordance with the policies content requests on behalf of an uCDN in accordance with the policies
defined by the uCDN. defined by the uCDN.
This document focuses on the CDNI Metadata interface which enables a This document focuses on the CDNI metadata interface which enables a
dCDN to obtain CDNI Metadata from an uCDN so that the dCDN can dCDN to obtain CDNI metadata from an uCDN so that the dCDN can
properly process and respond to: properly process and respond to:
o Redirection requests received over the CDNI Request Routing o Redirection requests received over the CDNI Request Routing
Redirection interface [I-D.ietf-cdni-redirection]. Redirection interface [I-D.ietf-cdni-redirection].
o Content requests received directly from User Agents. o Content requests received directly from User Agents.
Specifically, this document specifies: Specifically, this document specifies:
o A data structure for mapping content requests and redirection o A data structure for mapping content requests and redirection
requests to CDNI Metadata objects (Section 3 and Section 4.1). requests to CDNI metadata objects (Section 3 and Section 4.1).
o An initial set of CDNI Generic Metadata objects (Section 4.2). o An initial set of CDNI Generic metadata objects (Section 4.2).
o A RESTful web service for the transfer of CDNI Metadata o A HTTP web service for the transfer of CDNI metadata (Section 6).
(Section 6).
1.1. Terminology 1.1. Terminology
This document reuses the terminology defined in [RFC6707]. This document reuses the terminology defined in [RFC6707].
Additionally, the following terms are used throughout this document Additionally, the following terms are used throughout this document
and are defined as follows: and are defined as follows:
o Object - a collection of properties. o Object - a collection of properties.
o Property - a key and value pair where the key is a property name o Property - a key and value pair where the key is a property name
and the value is the property value or an object. and the value is the property value or another object.
This document uses the phrase "[Object] A contains [Object] B" for
simplicity when a strictly accurate phrase would be "[Object] A
contains or references (via a Link object) [Object] B".
1.2. Supported Metadata Capabilities 1.2. Supported Metadata Capabilities
Only the metadata for a small set of initial capabilities is Only the metadata for a small set of initial capabilities is
specified in this document. This set provides the minimum amount of specified in this document. This set provides the minimum amount of
metadata for basic CDN interoperability while still meeting the metadata for basic CDN interoperability while still meeting the
requirements set forth by [RFC7337]. requirements set forth by [RFC7337].
The following high-level functionality is configured via the metadata The following high-level functionality can be configured via the CDNI
described in Section 4: metadata objects specified in Section 4:
o Acquisition Source: Metadata for allowing a dCDN to fetch content o Acquisition Source: Metadata for allowing a dCDN to fetch content
from a uCDN. from a uCDN.
o Delivery Access Control: Metadata for restricting (or permitting) o Delivery Access Control: Metadata for restricting (or permitting)
access to content based on any of the following factors: access to content based on any of the following factors:
* Location * Location
* Time Window * Time Window
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The metadata encoding described by this document is extensible in The metadata encoding described by this document is extensible in
order to allow for future additions to this list. order to allow for future additions to this list.
The set of metadata specified in this document, covering the initial The set of metadata specified in this document, covering the initial
capabilities above, is only able to support CDN interconnection for capabilities above, is only able to support CDN interconnection for
the delivery of content by a dCDN using HTTPv1.1 [RFC7230] and for a the delivery of content by a dCDN using HTTPv1.1 [RFC7230] and for a
dCDN to be able to acquire content from a uCDN using either HTTPv1.1 dCDN to be able to acquire content from a uCDN using either HTTPv1.1
or HTTPv1.1 over TLS [RFC2818]. or HTTPv1.1 over TLS [RFC2818].
Supporting CDN interconnection for the delivery of content using Supporting CDN interconnection for the delivery of content using
unencrypted HTTPv2.0 [I-D.ietf-httpbis-http2] (as well as for a dCDN unencrypted HTTPv2.0 [RFC7540] (as well as for a dCDN to acquire
to acquire content using unencrypted HTTPv2.0 or HTTPv2.0 over TLS) content using unencrypted HTTPv2.0 or HTTPv2.0 over TLS) requires the
requires the registration of these protocol names in the CDNI registration of these protocol names in the CDNI Metadata Protocol
Metadata Protocol Registry. Registry.
Supporting CDN interconnection for the delivery of content using Supporting CDN interconnection for the delivery of content using
HTTPv1.1 over TLS or HTTPv2.0 over TLS requires specifying additional HTTPv1.1 over TLS or HTTPv2.0 over TLS requires specifying additional
metadata objects to carry the properties required to establish a TLS metadata objects to carry the properties required to establish a TLS
session, for example metadata to describe the certificate to use as session, for example metadata to describe the certificate to use as
part of the TLS handshake. part of the TLS handshake.
2. Design Principles 2. Design Principles
The CDNI Metadata interface was designed to achieve the following The CDNI metadata interface was designed to achieve the following
objectives: objectives:
1. Cacheability of CDNI metadata objects. 1. Cacheability of CDNI metadata objects.
2. Deterministic mapping from redirection requests and content 2. Deterministic mapping from redirection requests and content
requests to CDNI metadata properties. requests to CDNI metadata properties.
3. Support for DNS redirection as well as application-specific 3. Support for DNS redirection as well as application-specific
redirection (for example HTTP redirection). redirection (for example HTTP redirection).
4. Minimal duplication of CDNI metadata. 4. Minimal duplication of CDNI metadata.
5. Leveraging of existing protocols. 5. Leveraging of existing protocols.
Cacheability improves the latency of acquiring metadata while Cacheability improves the latency of acquiring metadata while
maintaining its freshness, and therefore improves the latency of maintaining its freshness, and therefore improves the latency of
serving content requests and redirection requests, without serving content requests and redirection requests, without
sacrificing accuracy. The CDNI Metadata interface uses HTTP and its sacrificing accuracy. The CDNI metadata interface uses HTTP and its
existing caching mechanisms to achieve CDNI metadata cacheability. existing caching mechanisms to achieve CDNI metadata cacheability.
Deterministic mappings from content to metadata properties eliminates Deterministic mappings from content to metadata properties eliminates
ambiguity and ensures that policies are applied consistently by all ambiguity and ensures that policies are applied consistently by all
dCDNs. dCDNs.
Support for both HTTP and DNS redirection ensures that the CDNI Support for both HTTP and DNS redirection ensures that the CDNI
Metadata interface can be used for HTTP and DNS redirection and also metadata interface can be used for HTTP and DNS redirection and also
meets the same design principles for both HTTP and DNS based meets the same design principles for both HTTP and DNS based
redirection schemes. redirection schemes.
Minimal duplication of CDNI metadata provides space efficiency on Minimal duplication of CDNI metadata provides space efficiency on
storage in the CDNs, on caches in the network, and across the network storage in the CDNs, on caches in the network, and across the network
between CDNs. between CDNs.
Leveraging existing protocols avoids reinventing common mechanisms Leveraging existing protocols avoids reinventing common mechanisms
such as data structure encoding (e.g., I-JSON [RFC7492]) and data such as data structure encoding (by leveraging I-JSON [RFC7493]) and
transport (e.g., HTTP [RFC7230]). data transport (by leveraging HTTP [RFC7230]).
3. CDNI Metadata model 3. CDNI Metadata object model
The CDNI Metadata model describes a data structure for mapping The CDNI metadata object model describes a data structure for mapping
redirection requests and content requests to metadata properties. redirection requests and content requests to metadata properties.
Metadata properties describe how to acquire content from an uCDN, Metadata properties describe how to acquire content from an uCDN,
authorize access to content, and deliver content from a dCDN. The authorize access to content, and deliver content from a dCDN. The
data model relies on the assumption that these metadata properties object model relies on the assumption that these metadata properties
may be aggregated based on the hostname of the content and may be aggregated based on the hostname of the content and
subsequently on the resource path of the content. The data model subsequently on the resource path (URI) of the content. The object
associates a set of CDNI Metadata properties with a Hostname to form model associates a set of CDNI metadata properties with a Hostname to
a default set of metadata properties for content delivered on behalf form a default set of metadata properties for content delivered on
of that Hostname. That default set of metadata properties can be behalf of that Hostname. That default set of metadata properties can
overridden by properties that apply to specific paths within a URI. be overridden by properties that apply to specific paths within a
URI.
Different Hostnames and URI paths will be associated with different Different Hostnames and URI paths will be associated with different
sets of CDNI Metadata properties in order to describe the required sets of CDNI metadata properties in order to describe the required
behaviour when a dCDN surrogate is processing User Agent requests for behaviour when a dCDN surrogate or request router is processing User
content at that Hostname or URI path. As a result of this structure, Agent requests for content at that Hostname or URI path. As a result
significant commonality may exist between the CDNI Metadata of this structure, significant commonality may exist between the CDNI
properties specified for different Hostnames, different URI paths metadata properties specified for different Hostnames, different URI
within a Hostname and different URI paths on different Hostnames. paths within a Hostname and different URI paths on different
For example the definition of which User Agent IP addresses should be Hostnames. For example the definition of which User Agent IP
treated as being grouped together into a single network or geographic addresses should be treated as being grouped together into a single
location is likely to be common for a number of different Hostnames. network or geographic location is likely to be common for a number of
Another example is that although a uCDN is likely to have several different Hostnames. Another example is that although a uCDN is
different policies configured to express geo-blocking rules, it is likely to have several different policies configured to express geo-
likely that a single geo-blocking policy would be applied to multiple blocking rules, it is likely that a single geo-blocking policy would
Hostnames delivered through the CDN. be applied to multiple Hostnames delivered through the CDN.
In order to enable the CDNI Metadata for a given Hostname or URI Path In order to enable the CDNI metadata for a given Hostname or URI Path
to be decomposed into sets of CDNI Metadata properties that can be to be decomposed into sets of CDNI metadata properties that can be
reused by multiple Hostnames and URI Paths, the CDNI Metadata reused by multiple Hostnames and URI Paths, the CDNI metadata
interface specified in this document splits the CDNI Metadata into a interface specified in this document splits the CDNI metadata into a
number of objects. Efficiency is improved by enabling a single CDNI number of objects. Efficiency is improved by enabling a single CDNI
Metadata object (that is shared across Hostname and/or URI paths) to metadata object (that is shared across Hostname and/or URI paths) to
be retrieved and stored by a dCDN once, even if it is referenced by be retrieved and stored by a dCDN once, even if it is referenced by
the CDNI Metadata of multiple Hostnames or of multiple URI paths. the CDNI metadata of multiple Hostnames or of multiple URI paths.
Important Note: Any CDNI Metadata object that contains another CDNI Important Note: Any CDNI metadata object A that contains another CDNI
Metadata object may, instead of including the second object embedded metadata object B may, instead of including the second object B
within itself, include a Link object that contains a URI that can be embedded within object A, include a Link object that contains a URI
dereferenced to retrieve the complete serialized representation of that can be dereferenced to retrieve the complete serialized
the second metadata object. The remainder of this document uses the representation of the second metadata object B. The remainder of
phrase "[Object] X contains [Object] Y" for simplicity when a this document uses the phrase "[Object] A contains [Object] B" for
strictly accurate phrase would be "[Object] X contains or references simplicity when a strictly accurate phrase would be "[Object] A
(via a Link object) [Object] Y". contains or references (via a Link object) [Object] B". It is
generally a deployment choice for the uCDN implementation to decide
when and which CDNI metadata objects to embed and which to make
available as separate resources via Link objects.
Section 3.1 introduces a high level description of the HostIndex, Section 3.1 introduces a high level description of the HostIndex,
HostMatch, HostMetadata, PathMatch, PatternMatch and PathMetadata HostMatch, HostMetadata, PathMatch, PatternMatch and PathMetadata
objects and describes the relationships between those objects. objects and describes the relationships between those objects.
Section 3.2 introduces a high level description of the CDNI Section 3.2 introduces a high level description of the CDNI
GenericMetadata object which represents the level at which CDNI GenericMetadata object which represents the level at which CDNI
Metadata override occurs between HostMetadata and PathMetadata metadata override occurs between HostMetadata and PathMetadata
objects. objects.
Section 4 describes in detail the specific CDNI Metadata objects and Section 4 describes in detail the specific CDNI metadata objects and
properties which may be contained within a CDNI GenericMetadata properties specified by this document which can be contained within a
object. CDNI GenericMetadata object.
3.1. HostIndex, HostMatch, HostMetadata, PathMatch, PatternMatch and 3.1. HostIndex, HostMatch, HostMetadata, PathMatch, PatternMatch and
PathMetadata objects PathMetadata objects
The relationships between the HostIndex, HostMatch, HostMetadata,
PathMatch, PatternMatch and PathMetadata objects are described in
Figure 1.
+---------+ +---------+ +------------+
|HostIndex+-(*)->|HostMatch+-(1)->|HostMetadata+-------(*)------+
+---------+ +---------+ +------+-----+ |
| |
(*) |
| V
--> Contains or References V ******************
(1) One and only one +---------+ *Generic Metadata*
(*) Zero or more +--->|PathMatch| * Objects *
| +----+---++ ******************
| | | ^
(*) (1) (1) +------------+ |
| | +->|PatternMatch| |
| V +------------+ |
| +------------+ |
+--+PathMetadata+-------(*)------+
+------------+
Figure 1: Relationships between CDNI Metadata Objects (Diagram
Representation)
A HostIndex object (see Section 4.1.1) contains a list of HostMatch A HostIndex object (see Section 4.1.1) contains a list of HostMatch
objects (see Section 4.1.2) that contain Hostnames (and/or IP objects (see Section 4.1.2) that contain Hostnames (and/or IP
addresses) for which content requests may be delegated to the dCDN. addresses) for which content requests may be delegated to the dCDN.
The HostIndex is the starting point for accessing the uCDN CDNI The HostIndex is the starting point for accessing the uCDN CDNI
Metadata data store. It enables the dCDN to deterministically metadata data store. It enables the dCDN to deterministically
discover, on receipt of a User Agent request for content, which other discover, on receipt of a User Agent request for content, which other
CDNI Metadata objects it requires in order to deliver the requested CDNI metadata objects it requires in order to deliver the requested
content. content.
The HostIndex links Hostnames (and/or IP addresses) to HostMetadata The HostIndex links Hostnames (and/or IP addresses) to HostMetadata
objects (see Section 4.1.3) via HostMatch objects. A HostMatch objects (see Section 4.1.3) via HostMatch objects. A HostMatch
object defines a hostname (or IP address) to match against a object defines a Hostname (or IP address) to match against a
requested host and contains a HostMetadata object. requested host and contains a HostMetadata object.
HostMetadata objects contain the default CDNI Metadata within HostMetadata objects contain the default CDNI metadata within
GenericMetadata objects (see Section 4.1.7) required to serve content GenericMetadata objects (see Section 4.1.7) required to serve content
for that host. When looking up CDNI Metadata, the dCDN looks up the for that host. When looking up CDNI metadata, the dCDN looks up the
requested Hostname (or IP address) against the HostMatch entries in requested Hostname (or IP address) against the HostMatch entries in
the HostIndex, from there it can find HostMetadata which describes the HostIndex, from there it can find HostMetadata which describes
the default properties for each host as well as PathMetadata objects the default properties for each host as well as PathMetadata objects
(see Section 4.1.6), via PathMatch objects (see Section 4.1.4), which (see Section 4.1.6), via PathMatch objects (see Section 4.1.4), which
may override those properties for given URI paths within the host. may override those properties for given URI paths within the host.
The CDNI metadata contained in HostMetadata objects is applied to The CDNI metadata contained in HostMetadata objects is applied to
content requests for which there is not more specific metadata, i.e. content requests for which there is not more specific metadata, i.e.
for content requests that do not match any of the PathMatch objects for content requests that do not match any of the PathMatch objects
contained by that HostMetadata object and its child PathMetadata contained by that HostMetadata object and its child PathMetadata
objects. objects.
HostMetadata may also contain PathMatch objects. PathMatch objects HostMetadata can also contain PathMatch objects. PathMatch objects
define patterns, contained inside PatternMatch objects (see define patterns, contained inside PatternMatch objects (see
Section 4.1.5), to match against the requested URI path, and contain Section 4.1.5), to match against the requested URI path, and contain
PathMetadata objects which contain the GenericMetadata objects to be PathMetadata objects which contain the GenericMetadata objects to be
applied when a content request matches against the defined URI path applied when a content request matches against the defined URI path
pattern. PatternMatch objects contain the pattern strings and flags pattern. PatternMatch objects contain the pattern strings and flags
that describe the URI path that a PathMatch applies to. that describe the URI path that a PathMatch applies to.
PathMetadata objects override the CDNI Metadata in the HostMetadata PathMetadata objects override the CDNI metadata in the HostMetadata
object or one or more preceding PathMetadata objects with more object or one or more parent PathMetadata objects with more specific
specific CDNI Metadata that applies to content requests matching the CDNI metadata that applies to content requests matching the URI
URI pattern defined in the PatternMatch object of that PathMatch pattern defined in the PatternMatch object of that PathMatch object.
object. A PathMetadata object may also contain PathMatch objects in A PathMetadata object may also contain PathMatch objects in order to
order to recursively define more specific URI paths that require recursively define more specific URI paths that require different
different (e.g., more specific) CDNI Metadata to this one. (e.g., more specific) CDNI metadata to this one.
A GenericMetadata object contains individual CDNI Metadata objects A GenericMetadata object contains individual CDNI metadata objects
which define the specific policies and attributes needed to properly which define the specific policies and attributes needed to properly
deliver the associated content. For example, a GenericMetadata deliver the associated content. For example, a GenericMetadata
object may describe the source from which a CDN may acquire a piece object may describe the source from which a CDN may acquire a piece
of content. The GenericMetadata object is an atomic unit that may be of content. The GenericMetadata object is an atomic unit that may be
referenced by HostMetadata and/or PathMetadata objects. referenced by HostMetadata and/or PathMetadata objects.
For example, if "example.com" is a content provider, a HostMatch For example, if "example.com" is a content provider, a HostMatch
object may include an entry for "example.com" with the URI of the object may include an entry for "example.com" with the URI of the
associated HostMetadata object. The HostMetadata object for associated HostMetadata object. The HostMetadata object for
"example.com" describes the metadata properties which apply to "example.com" describes the metadata properties which apply to
"example.com" and could contain PathMatches for "example.com/ "example.com" and could contain PathMatches for "example.com/
movies/*" and "example.com/music/*", which in turn reference movies/*" and "example.com/music/*", which in turn reference
corresponding PathMetadata objects that contain the CDNI Metadata corresponding PathMetadata objects that contain the CDNI metadata
objects for those more specific URI paths. The PathMetadata object objects for those more specific URI paths. The PathMetadata object
for "example.com/movies/*" describes CDNI Metadata which apply to for "example.com/movies/*" describes CDNI metadata which apply to
that URI path and could contain a PathMatch object for that URI path and could contain a PathMatch object for
"example.com/movies/hd/*" which would reference the corresponding "example.com/movies/hd/*" which would reference the corresponding
PathMetadata object for the "example.com/movies/hd/" path prefix. PathMetadata object for the "example.com/movies/hd/" path prefix.
The relationships between the HostIndex, HostMatch, HostMetadata,
PathMatch, PatternMatch and PathMetadata objects are described in
Figure 1.
+---------+ +---------+ +------------+
|HostIndex+-(*)->|HostMatch+-(1)->|HostMetadata+-------(*)------+
+---------+ +---------+ +------+-----+ |
| |
(*) |
| V
--> Contains or References V ******************
(1) One and only one +---------+ *Generic Metadata*
(*) Zero or more +--->|PathMatch| * Objects *
| +----+---++ ******************
| | | ^
(*) (1) (1) +------------+ |
| | +->|PatternMatch| |
| V +------------+ |
| +------------+ |
+--+PathMetadata+-------(*)------+
+------------+
Figure 1: Relationships between CDNI Metadata Objects (Diagram
Representation)
The relationships in Figure 1 are also represented in tabular format The relationships in Figure 1 are also represented in tabular format
in Table 1 below. in Table 1 below.
+--------------+----------------------------------------------------+ +--------------+----------------------------------------------------+
| Data Object | Objects it contains or references | | Data Object | Objects it contains or references |
+--------------+----------------------------------------------------+ +--------------+----------------------------------------------------+
| HostIndex | 0 or more HostMatch objects. | | HostIndex | 0 or more HostMatch objects. |
| HostMatch | 1 HostMetadata object. | | HostMatch | 1 HostMetadata object. |
| HostMetadata | 0 or more PathMatch objects. 0 or more | | HostMetadata | 0 or more PathMatch objects. 0 or more |
| | GenericMetadata objects. | | | GenericMetadata objects. |
| PathMatch | 1 PatternMatch object. 1 PathMetadata object. | | PathMatch | 1 PatternMatch object. 1 PathMetadata object. |
| PatternMatch | Does not contain or reference any other objects. | | PatternMatch | Does not contain or reference any other objects. |
| PathMetadata | 0 or more PathMatch objects. 0 or more | | PathMetadata | 0 or more PathMatch objects. 0 or more |
| | GenericMetadata objects. | | | GenericMetadata objects. |
+--------------+----------------------------------------------------+ +--------------+----------------------------------------------------+
Table 1: Relationships between CDNI Metadata Objects Table 1: Relationships between CDNI Metadata Objects
(Table Representation) (Table Representation)
3.2. Generic CDNI Metadata Object Properties 3.2. Generic CDNI Metadata Objects
The HostMetadata and PathMetadata objects contain or can reference
other CDNI Metadata objects that contain properties which describe
how User Agent requests for content should be processed, for example
where to acquire the content, authorization rules that should be
applied, delivery location restrictions and so on. Each such CDNI
Metadata object is a specialization of a CDNI GenericMetadata object.
The GenericMetadata object abstracts the basic information required The HostMetadata and PathMetadata objects contain other CDNI metadata
for Metadata override and Metadata distribution, from the specifics objects that contain properties which describe how User Agent
of any given property (e.g., property semantics, enforcement options, requests for content should be processed, for example where to
acquire the content from, authorization rules that should be applied,
geo-blocking restrictions and so on. Each such CDNI metadata object
is a specialization of a CDNI GenericMetadata object. The
GenericMetadata object abstracts the basic information required for
metadata override and metadata distribution, from the specifics of
any given property (e.g., property semantics, enforcement options,
etc.). etc.).
The GenericMetadata object defines the type of properties contained The GenericMetadata object defines the type of properties contained
within it as well as whether or not the properties are "mandatory-to- within it as well as whether or not the properties are "mandatory-to-
enforce". If the dCDN does not understand or support the property enforce". If the dCDN does not understand or support the property
type and the property type is "mandatory-to-enforce", the dCDN MUST type and the property type is "mandatory-to-enforce", the dCDN MUST
NOT serve the content to the User Agent. If the dCDN does not NOT serve the content to the User Agent. If the dCDN does not
understand or support the property type and the property type is not understand or support the property type and the property type is not
"mandatory-to-enforce", then that GenericMetadata object may be "mandatory-to-enforce", then that GenericMetadata object may be
safely ignored and the dCDN MUST process the content request in safely ignored and the dCDN MUST process the content request in
accordance with the rest of the CDNI metadata. accordance with the rest of the CDNI metadata.
Although a CDN MUST NOT serve content to a User Agent if a Although a CDN MUST NOT serve content to a User Agent if a
"mandatory-to-enforce" property cannot be enforced, it may be "safe- "mandatory-to-enforce" property cannot be enforced, it may be "safe-
to-redistribute" that metadata to another CDN without modification. to-redistribute" that metadata to another CDN without modification.
For example, in the cascaded CDN case, a transit CDN may pass through For example, in the cascaded CDN case, a transit CDN (tCDN) may pass
"mandatory-to-enforce" metadata to a dCDN. For Metadata which does through "mandatory-to-enforce" metadata to a dCDN. For metadata
not require customization or translation (i.e., metadata that is which does not require customization or translation (i.e., metadata
"safe-to-redistribute"), the data representation received off the that is "safe-to-redistribute"), the data representation received off
wire MAY be stored and redistributed without being natively the wire MAY be stored and redistributed without being natively
understood or supported by the transit CDN. However, for Metadata understood or supported by the transit CDN. However, for metadata
which requires translation, transparent redistribution of the uCDN which requires translation, transparent redistribution of the uCDN
Metadata values might not be appropriate. Certain Metadata may be metadata values might not be appropriate. Certain metadata may be
safely, though possibly not optimally, redistributed unmodified. For safely, though possibly not optimally, redistributed unmodified. For
example, source acquisition address may not be optimal if example, source acquisition address may not be optimal if
transparently redistributed, but might still work. transparently redistributed, but might still work.
Redistribution safety MUST be specified for each GenericMetadata. If Redistribution safety MUST be specified for each GenericMetadata. If
a CDN does not understand or support a given GenericMetadata property a CDN does not understand or support a given GenericMetadata property
type and the property type is not "safe-to-redistribute", before type and the property type is not "safe-to-redistribute", before
redistributing the metadata, the CDN MUST set the "incomprehensible" redistributing the metadata, the CDN MUST set the "incomprehensible"
flag for the GenericMetadata property that it did not understand and flag for the GenericMetadata object that it did not understand and
was marked as not "safe-to-redistribute". The "incomprehensible" was marked as not "safe-to-redistribute". The "incomprehensible"
flag signals to a dCDN that the metadata was not properly transformed flag signals to a dCDN that the metadata was not properly transformed
by the transit CDN. A CDN MUST NOT attempt to use metadata that has by the transit CDN. A CDN MUST NOT attempt to use metadata that has
been marked as "incomprehensible" by a uCDN. been marked as "incomprehensible" by a uCDN.
Transit CDNs MUST NOT change the value of "mandatory-to-enforce" or Transit CDNs MUST NOT change the value of "mandatory-to-enforce" or
"safe-to-redistribute" when propagating metadata to a dCDN. Although "safe-to-redistribute" when propagating metadata to a dCDN. Although
a transit CDN may set the value of "incomprehensible" to true, a a transit CDN may set the value of "incomprehensible" to true, a
transit CDN MUST NOT change the value of "incomprehensible" from true transit CDN MUST NOT change the value of "incomprehensible" from true
to false. to false.
skipping to change at page 12, line 25 skipping to change at page 12, line 23
| | | | "incomprehensible" to True when | | | | | "incomprehensible" to True when |
| | | | redistributing. | | | | | redistributing. |
| False | False | True | Can serve. Can redistribute either | | False | False | True | Can serve. Can redistribute either |
| | | | by transforming not StR metadata (if | | | | | by transforming not StR metadata (if |
| | | | the CDN knows how to do so safely), | | | | | the CDN knows how to do so safely), |
| | | | otherwise MUST set | | | | | otherwise MUST set |
| | | | "incomprehensible" to True when | | | | | "incomprehensible" to True when |
| | | | redistributing. | | | | | redistributing. |
| True | True | True | Can serve and redistribute. | | True | True | True | Can serve and redistribute. |
| True | True | False | MUST NOT serve but can redistribute. | | True | True | False | MUST NOT serve but can redistribute. |
| True | False | True | Can serve and redistribute. | | True | False | True | Can serve. Can redistribute either |
| | | | by transforming not StR metadata (if |
| | | | the CDN knows how to do so safely), |
| | | | otherwise MUST set |
| | | | "incomprehensible" to True when |
| | | | redistributing. |
| True | False | False | MUST NOT serve. MUST set | | True | False | False | MUST NOT serve. MUST set |
| | | | "incomprehensible" to True when | | | | | "incomprehensible" to True when |
| | | | redistributing. | | | | | redistributing. |
+-------+-------+------------+--------------------------------------+ +-------+-------+------------+--------------------------------------+
Table 2: Action to be taken by a tCDN for the different combinations Table 2: Action to be taken by a tCDN for the different combinations
of MtE and StR properties of MtE and StR properties
Table 3 describes the action to be taken by a dCDN for the different Table 3 describes the action to be taken by a dCDN for the different
combinations of "mandatory-to-enforce" (MtE) and "incomprehensible" combinations of "mandatory-to-enforce" (MtE) and "incomprehensible"
(Incomp) properties, when the dCDN either does or does not understand (Incomp) properties, when the dCDN either does or does not understand
the metadata in question: the metadata in question:
+-------+--------------+--------+-----------------------------------+ +-------+--------+--------------+-----------------------------------+
| MtE | Metadata | Incomp | Action | | MtE | Incomp | Metadata | Action |
| | Understood | | | | | | Understood | |
| | by dCDN | | | | | | by dCDN | |
+-------+--------------+--------+-----------------------------------+ +-------+--------+--------------+-----------------------------------+
| False | True | False | Can serve. | | False | False | True | Can serve. |
| False | True | True | Can serve but MUST NOT | | False | True | True | Can serve but MUST NOT |
| | | | interpret/apply any metadata | | | | | interpret/apply any metadata |
| | | | marked incomprehensible. | | | | | marked incomprehensible. |
| False | False | False | Can serve. | | False | False | False | Can serve. |
| False | False | True | Can serve but MUST NOT | | False | True | False | Can serve but MUST NOT |
| | | | interpret/apply any metadata | | | | | interpret/apply any metadata |
| | | | marked incomprehensible. | | | | | marked incomprehensible. |
| True | True | False | Can serve. | | True | False | True | Can serve. |
| True | True | True | MUST NOT serve. | | True | True | True | MUST NOT serve. |
| True | False | False | MUST NOT serve. | | True | False | False | MUST NOT serve. |
| True | False | True | MUST NOT serve. | | True | True | False | MUST NOT serve. |
+-------+--------------+--------+-----------------------------------+ +-------+--------+--------------+-----------------------------------+
Table 3: Action to be taken by a dCDN for the different combinations Table 3: Action to be taken by a dCDN for the different combinations
of MtE and Incomp properties of MtE and Incomp properties
3.3. Metadata Inheritance and Override 3.3. Metadata Inheritance and Override
In the Metadata model, a HostMetadata object may contain (or In the metadata object model, a HostMetadata object may contain
reference) multiple PathMetadata objects (via PathMatch objects). multiple PathMetadata objects (via PathMatch objects). Each
Each PathMetadata object may in turn contain (or reference) other PathMetadata object may in turn contain other PathMetadata objects.
PathMetadata objects. HostMetadata and PathMetadata objects form an HostMetadata and PathMetadata objects form an inheritance tree where
inheritance tree where each node in the tree inherits or overrides each node in the tree inherits or overrides the property values set
the property values set by its parent. by its parent.
GenericMetadata objects of a given type override all GenericMetadata GenericMetadata objects of a given type override all GenericMetadata
objects of the same type previously defined by any parent object in objects of the same type previously defined by any parent object in
the tree. GenericMetadata objects of a given type previously defined the tree. GenericMetadata objects of a given type previously defined
by a parent object in the tree are inherited when no object of the by a parent object in the tree are inherited when no object of the
same type is defined by the child object. For example, if same type is defined by the child object. For example, if
HostMetadata for the host "example.com" contains GenericMetadata HostMetadata for the host "example.com" contains GenericMetadata
objects of type LocationACL and TimeWindowACL, while a PathMetadata objects of type LocationACL and TimeWindowACL, while a PathMetadata
object which applies to "example.com/movies/*" defines an alternate object which applies to "example.com/movies/*" defines an alternate
GenericMetadata object of type TimeWindowACL, then: GenericMetadata object of type TimeWindowACL, then:
o the TimeWindowACL defined in the PathMetadata would override the o the TimeWindowACL defined in the PathMetadata would override the
TimeWindowACL defined in the HostMetadata for all User Agent TimeWindowACL defined in the HostMetadata for all User Agent
requests for content under "example.com/movies/", and requests for content under "example.com/movies/", and
o the LocationACL defined in the HostMetadata would be inherited for o the LocationACL defined in the HostMetadata would be inherited for
all User Agent requests for content under "example.com/movies/". all User Agent requests for content under "example.com/movies/".
o A single HostMetadata or PathMetadata object SHOULD NOT contain A single HostMetadata or PathMetadata object MUST NOT contain
multiple GenericMetadata objects of the same type. If a list of multiple GenericMetadata objects of the same type. If a list of
GenericMetadata contains objects of duplicate types, the receiver GenericMetadata contains objects of duplicate types, the receiver
MUST ignore all but the first object of each type. MUST ignore all but the first object of each type.
4. CDNI Metadata objects 4. CDNI Metadata objects
Section 4.1 provides the definitions of each metadata object type Section 4.1 provides the definitions of each metadata object type
introduced in Section 3. These metadata objects are described as introduced in Section 3. These metadata objects are described as
structural metadata objects as they provide the structure for the structural metadata objects as they provide the structure for the
inheritance tree and identify which specific properties apply to a inheritance tree and identify which specific GenericMetadata objects
given User Agent content request. apply to a given User Agent content request.
Section 4.2 provides the definitions for a base set of core metadata Section 4.2 provides the definitions for a base set of core metadata
objects which may be contained within a GenericMetadata object. objects which can be contained within a GenericMetadata object.
These metadata objects are described as property objects, as they These metadata objects govern how User Agent requests for content are
define the structure, semantics, and enforcement options for specific handled. GenericMetadata objects can contain other GenericMetadata
properties of the metadata being described. Property objects govern sub-objects (i.e., GenericMetadata sub-objects contained within the
how User Agent requests for content are handled. Property objects GenericMetadata object that refers to that GenericMetadata sub-
may be composed of, or contain references to, other property sub- object). As with all CDNI metadata objects, the value of the
objects (i.e., property objects contained within or referenced by the GenericMetadata sub-objects can be either a complete serialized
property object that refers to that property sub-object). As with representation of the sub-object, or a Link object that contains a
all CDNI Metadata object, the value of the property sub-objects can URI that can be dereferenced to retrieve the complete serialized
be either a complete serialized representation of the sub-object, or representation of the property sub-object.
a Link object that contains a URI that can be dereferenced to
retrieve the complete serialized representation of the property sub-
object.
Section 6.5 discusses the ability to extend the base set of metadata Section 6.5 discusses the ability to extend the base set of
objects specified in this document with additional standards based or GenericMetadata objects specified in this document with additional
vendor specific property objects that may be defined in the future in standards based or vendor specific GenericMetadata objects that may
separate documents. be defined in the future in separate documents.
dCDNs and tCDNs MUST support parsing of all CDNI metadata objects dCDNs and tCDNs MUST support parsing of all CDNI metadata objects
specified in this document. A dCDN does not have to implement the specified in this document. A dCDN does not have to implement the
underlying functionality represented by the metadata object, though underlying functionality represented by the metadata object, though
that may restrict the content that a given dCDN can serve. uCDNs as that may restrict the content that a given dCDN can serve. uCDNs as
generators of CDNI Metadata only need to support generating the CDNI generators of CDNI metadata only need to support generating the CDNI
metadata that they need in order to express the policies and metadata that they need in order to express the policies and
treatment required by the content they are describing. treatment required by the content they are describing.
CDNI metadata objects MUST be encoded as I-JSON objects [RFC7493]
containing a dictionary of (key,value) pairs where the keys are the
property names and the values are the associated property values.
See Section 6.4 for more details of the specific encoding rules for
CDNI metadata objects.
Note: In the following sections, the term "mandatory-to-specify" is Note: In the following sections, the term "mandatory-to-specify" is
used to convey which properties MUST be included for a given used to convey which properties MUST be included for a given
structural or property object. When mandatory-to-specify is structural or GenericMetadata object. When mandatory-to-specify is
specified as "Yes" by this document for an individual property, it specified as "Yes" by this document for an individual property, it
means that if the object containing that property is included in a means that if the object containing that property is included in a
metadata response, then the mandatory-to-specify property MUST also metadata response, then the mandatory-to-specify property MUST also
be included (directly or by reference) in the response, e.g., a be included (directly or by reference) in the response, e.g., a
HostMatch property object without a host to match against does not HostMatch property object without a host to match against does not
make sense, therefore, the host property is mandatory-to-specify make sense, therefore, the host property is mandatory-to-specify
inside a HostMatch object. inside a HostMatch object.
4.1. Definitions of the CDNI structural metadata objects 4.1. Definitions of the CDNI structural metadata objects
Each of the sub-sections below describe the structural objects Each of the sub-sections below describe the structural objects
introduced in Section 3.1. introduced in Section 3.1.
4.1.1. HostIndex 4.1.1. HostIndex
The HostIndex object is the entry point into the CDNI Metadata The HostIndex object is the entry point into the CDNI metadata
hierarchy. It contains a list of HostMatch objects. An incoming hierarchy. It contains a list of HostMatch objects. An incoming
content request is checked against the hostname (or IP address) content request is checked against the Hostname (or IP address)
specified by each of the listed HostMatch objects to find the specified by each of the listed HostMatch objects to find the
HostMatch object which applies to the request. HostMatch object which applies to the request.
Property: hosts Property: hosts
Description: List of HostMatch objects. Hosts (HostMatch Description: List of HostMatch objects. Hosts (HostMatch
objects) MUST be evaluated in the order they appear and the objects) MUST be evaluated in the order they appear and the
first HostMatch object that matches the content request being first HostMatch object that matches the content request being
processed MUST be used. processed MUST be used.
skipping to change at page 16, line 7 skipping to change at page 16, line 7
}, },
{ {
"type": "application/cdni.HostMatch.v1+json", "type": "application/cdni.HostMatch.v1+json",
"href": "http://metadata.ucdn.example/hostmatch1234" "href": "http://metadata.ucdn.example/hostmatch1234"
} }
] ]
} }
4.1.2. HostMatch 4.1.2. HostMatch
The HostMatch object contains a hostname or IP address to match The HostMatch object contains a Hostname or IP address to match
against content requests. The HostMatch object also contains or against content requests. The HostMatch object also contains a
references a HostMetadata object to apply if a match is found. HostMetadata object to apply if a match is found.
Property: host Property: host
Description: String (hostname or IP address) to match against Description: String (Hostname or IP address) to match against
the requested host. In order for a hostname or IP address in a the requested host. In order for a Hostname or IP address in a
content request to match the hostname or IP address in the host content request to match the Hostname or IP address in the host
property the value when converted to lowercase in the content property the value when converted to lowercase in the content
request MUST be identical to the value of the host property request MUST be identical to the value of the host property
when converted to lowercase. when converted to lowercase. IPv4 addresses MUST be encoded as
specified by the 'IPv4address' rule in Section 3.2.2 of
[RFC3986]. IPv6 addresses MUST be encoded in one of the IPv6
address formats specified in [RFC5952] although receivers MUST
support all IPv6 address formats specified in [RFC4291].
Type: String Type: String
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: host-metadata Property: host-metadata
Description: CDNI Metadata to apply when delivering content Description: CDNI metadata to apply when delivering content
that matches this host. that matches this host.
Type: HostMetadata Type: HostMetadata
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Example HostMatch object with an embedded HostMetadata object: Example HostMatch object with an embedded HostMetadata object:
{ {
"host": "video.example.com", "host": "video.example.com",
"host-metadata" : { "host-metadata" : {
<Properties of embedded HostMetadata object> <Properties of embedded HostMetadata object>
} }
} }
Example HostMatch object referencing a HostMetadata object: Example HostMatch object referencing (via a Link object, see
Section 4.3.1) a HostMetadata object:
{ {
"host": "video.example.com", "host": "video.example.com",
"host-metadata" : { "host-metadata" : {
"type": "application/cdni.HostMetadata.v1+json", "type": "application/cdni.HostMetadata.v1+json",
"href": "http://metadata.ucdn.example/host1234" "href": "http://metadata.ucdn.example/host1234"
} }
} }
4.1.3. HostMetadata 4.1.3. HostMetadata
A HostMetadata object contains (or references) the CDNI Metadata A HostMetadata object contains the CDNI metadata properties for
properties for content served for a particular host (defined in the content served for a particular host (defined in the HostMatch
HostMatch object) and possibly child PathMatch objects. object) and possibly child PathMatch objects.
Property: metadata Property: metadata
Description: List of host related metadata. Description: List of host related metadata.
Type: List of GenericMetadata objects Type: List of GenericMetadata objects
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: paths Property: paths
skipping to change at page 18, line 29 skipping to change at page 18, line 29
], ],
"paths": [ "paths": [
{ {
<Properties of embedded PathMatch object> <Properties of embedded PathMatch object>
} }
] ]
} }
4.1.4. PathMatch 4.1.4. PathMatch
The PathMatch object contains (or references) an expression given as A PathMatch object contains a pattern within a PatternMatch object to
a PatternMatch object to match against a resource URI path and match against a resource's URI path and contains a PathMetadata
contains or references a PathMetadata object to apply if a match is object to apply if the resource's URI path matches the pattern within
found. the PatternMatch object.
Property: path-pattern Property: path-pattern
Description: Pattern to match against the requested path, i.e., Description: Pattern to match against the requested resource's
against the [RFC3986] path-absolute. URI path, i.e., against the [RFC3986] path-absolute.
Type: PatternMatch Type: PatternMatch
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: path-metadata Property: path-metadata
Description: CDNI Metadata to apply when delivering content Description: CDNI metadata to apply when delivering content
that matches this path. that matches the associated PatternMatch.
Type: PathMetadata Type: PathMetadata
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Example PathMatch object referencing the PathMetadata object to use Example PathMatch object referencing the PathMetadata object to use
for URIs that match the case-sensitive URI path pattern "/movies/*" for URIs that match the case-sensitive URI path pattern "/movies/*"
(contained within an embedded PatternMatch object): (contained within an embedded PatternMatch object):
{ {
skipping to change at page 19, line 30 skipping to change at page 19, line 30
4.1.5. PatternMatch 4.1.5. PatternMatch
A PatternMatch object contains the pattern string and flags that A PatternMatch object contains the pattern string and flags that
describe the PathMatch expression. describe the PathMatch expression.
Property: pattern Property: pattern
Description: A pattern for string matching. The pattern may Description: A pattern for string matching. The pattern may
contain the wildcards * and ?, where * matches any sequence of contain the wildcards * and ?, where * matches any sequence of
characters (including the empty string) and ? matches exactly characters (including the empty string) and ? matches exactly
one character. The three literals \ , * and ? should be one character. The three literals $, * and ? should be escaped
escaped as \\, \* and \?. All other characters are treated as as $$, $* and $?. All other characters are treated as literals.
literals.
Type: String Type: String
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: case-sensitive Property: case-sensitive
Description: Flag indicating whether or not case-sensitive Description: Flag indicating whether or not case-sensitive
matching should be used. matching should be used.
skipping to change at page 20, line 11 skipping to change at page 20, line 11
when searching for a pattern match. Matching against query when searching for a pattern match. Matching against query
parameters to ignore MUST be case-insensitive. If all query parameters to ignore MUST be case-insensitive. If all query
parameters should be ignored then the list MUST be empty. parameters should be ignored then the list MUST be empty.
Type: List of String Type: List of String
Mandatory-to-Specify: No. Default is to include query strings Mandatory-to-Specify: No. Default is to include query strings
when matching. when matching.
Example PatternMatch object that matches the case-sensitive URI path Example PatternMatch object that matches the case-sensitive URI path
pattern "/movies/*". All query parameters will be ignored when
matching URIs requested from surrogates by content clients against
this path pattern:
{
"pattern": "/movies/*",
"case-sensitive": true,
"ignore-query-string": []
}
Example PatternMatch object that matches the case-sensitive URI path
pattern "/movies/*". The query parameter "sessionid" will be ignored pattern "/movies/*". The query parameter "sessionid" will be ignored
when matching URIs requested from surrogates by content clients when matching URIs requested from surrogates by content clients
against this path pattern: against this path pattern:
{ {
"pattern": "/movies/*", "pattern": "/movies/*",
"case-sensitive": true, "case-sensitive": true,
"ignore-query-string": ["sessionid"] "ignore-query-string": ["sessionid"]
} }
4.1.6. PathMetadata 4.1.6. PathMetadata
A PathMetadata object contains (or references) the CDNI Metadata A PathMetadata object contains the CDNI metadata properties for
properties for content served with the associated URI path (defined content requests that match against the associated URI path (defined
in a PathMatch object) and possibly child PathMatch objects. in a PathMatch object) and possibly child PathMatch objects.
Note that if DNS-based redirection is employed, then a dCDN will be Note that if DNS-based redirection is employed, then a dCDN will be
unable to evaulate any metadata at the PathMetadata level or below unable to evaulate any metadata at the PathMetadata level or below
against the content redirection request at request routing time against the content redirection request at request routing time
because only the content request hostname is available at request because only the hostname of the content request is available at
routing time. dCDNs SHOULD still process any metadata at the request routing time. dCDNs SHOULD still process any metadata at the
PathMetadata level or below before responding to the redirection PathMetadata level or below before responding to the redirection
request in order to detect if any unsupported metadata is specifed. request in order to detect if any unsupported metadata is specifed.
If any metadata is included that is not supported by the dCDN then If any metadata is included and marked as "mandatory-to-enforce"
the dCDN SHOULD NOT redirect the the content redirection request to which is not supported by the dCDN then the dCDN SHOULD NOT redirect
itself in order to avoid receiving content requests that it is not the the content redirection request to itself in order to avoid
able to satisfy/serve. receiving content requests that it is not able to satisfy/serve.
Property: metadata Property: metadata
Description: List of path related metadata. Description: List of path related metadata.
Type: List of GenericMetadata objects Type: List of GenericMetadata objects
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: paths Property: paths
skipping to change at page 21, line 4 skipping to change at page 21, line 14
Type: List of GenericMetadata objects Type: List of GenericMetadata objects
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: paths Property: paths
Description: Path specific rules. First match applies. Description: Path specific rules. First match applies.
Type: List of PathMatch objects Type: List of PathMatch objects
Mandatory-to-Specify: No. Mandatory-to-Specify: No.
Example PathMetadata object containing a number of embedded Example PathMetadata object containing a number of embedded
GenericMetadata objects that will describe the metadata to apply for GenericMetadata objects that describe the metadata to apply for the
the path defined in the parent PathMatch object. that will describe URI path defined in the parent PathMatch object.
the CDNI metadata for that path which overrides the default metadata
for the host:
{ {
"metadata": [ "metadata": [
{ {
<Properties of 1st embedded GenericMetadata object> <Properties of 1st embedded GenericMetadata object>
}, },
{ {
<Properties of 2nd embedded GenericMetadata object> <Properties of 2nd embedded GenericMetadata object>
}, },
... ...
{ {
<Properties of Nth embedded GenericMetadata object> <Properties of Nth embedded GenericMetadata object>
} }
], ],
} }
4.1.7. GenericMetadata 4.1.7. GenericMetadata
A GenericMetadata object is an abstraction for managing individual A GenericMetadata object is a wrapper for managing individual CDNI
CDNI Metadata properties in an opaque manner. metadata properties in an opaque manner.
Property: generic-metadata-type Property: generic-metadata-type
Description: Case-insensitive CDNI Metadata property object Description: Case-insensitive CDNI metadata object type.
type.
Type: String containing a MIME Media Type Type: String containing the Media Type of the object contained
in the generic-metadata-value property.
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: generic-metadata-value Property: generic-metadata-value
Description: CDNI metadata object.
Description: CDNI Metadata property object.
Type: Format/Type is defined by the value of generic-metadata- Type: Format/Type is defined by the value of generic-metadata-
type property above. type property above.
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: mandatory-to-enforce Property: mandatory-to-enforce
Description: Flag identifying whether or not the enforcement of Description: Flag identifying whether or not the enforcement of
the property Metadata is required. the property metadata is required.
Type: Boolean Type: Boolean
Mandatory-to-Specify: No. Default is to treat metadata as Mandatory-to-Specify: No. Default is to treat metadata as
mandatory to enforce (i.e., a value of True). mandatory to enforce (i.e., a value of True).
Property: safe-to-redistribute Property: safe-to-redistribute
Description: Flag identifying whether or not the property Description: Flag identifying whether or not the property
Metadata may be safely redistributed without modification. metadata may be safely redistributed without modification.
Type: Boolean Type: Boolean
Mandatory-to-Specify: No. Default is allow transparent Mandatory-to-Specify: No. Default is allow transparent
redistribution (i.e., a value of True). redistribution (i.e., a value of True).
Property: incomprehensible Property: incomprehensible
Description: Flag identifying whether or not any CDN in the Description: Flag identifying whether or not any CDN in the
chain of delegation has failed to understand and/or failed to chain of delegation has failed to understand and/or failed to
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Mandatory-to-Specify: No. Default is comprehensible (i.e., a Mandatory-to-Specify: No. Default is comprehensible (i.e., a
value of False). value of False).
Example GenericMetadata object containing a metadata object that Example GenericMetadata object containing a metadata object that
applies to the applicable URI path and/or host (within a parent applies to the applicable URI path and/or host (within a parent
PathMetadata and/or HostMetadata object): PathMetadata and/or HostMetadata object):
{ {
"mandatory-to-enforce": true, "mandatory-to-enforce": true,
"generic-metadata-type": <MIME Media Type of this metadata object>, "generic-metadata-type": <Media Type of this metadata object>,
"generic-metadata-value": "generic-metadata-value":
{ {
<Properties of this metadata object> <Properties of this metadata object>
} }
} }
4.2. Definitions of the initial set of CDNI Generic Metadata objects 4.2. Definitions of the initial set of CDNI Generic Metadata objects
The property objects defined below are intended to be used in the The objects defined below are intended to be used in the
GenericMetadata object generic-metadata-value field as defined in GenericMetadata object generic-metadata-value field as defined in
Section 4.1.7 and their generic-metadata-type property MUST be set to Section 4.1.7 and their generic-metadata-type property MUST be set to
the appropriate Media Type as defined in Table 4. the appropriate Media Type as defined in Table 4.
4.2.1. SourceMetadata 4.2.1. SourceMetadata
Source Metadata provides the dCDN information about content Source metadata provides the dCDN with information about content
acquisition, i.e., how to contact an uCDN Surrogate or an Origin acquisition, i.e., how to contact an uCDN Surrogate or an Origin
Server to obtain the content to be served. The sources are not Server to obtain the content to be served. The sources are not
necessarily the actual Origin Servers operated by the CSP but might necessarily the actual Origin Servers operated by the CSP but might
be a set of Surrogates in the uCDN. be a set of Surrogates in the uCDN.
Endpoints within a source should be treated as equivalent/equal so
one can specify a list of sources in preference order and for each
source/preference rank one can specify a list of endpoints that are
equivalent, e.g., a pool of servers that are not behind a load
balancer.
Property: sources Property: sources
Description: Sources from which the dCDN can acquire content, Description: Sources from which the dCDN can acquire content,
listed in order of preference. listed in order of preference.
Type: List of Source objects Type: List of Source objects (see Section 4.2.1.1)
Mandatory-to-Specify: No. Default is to use static Mandatory-to-Specify: No. Default is to use static
configuration, out-of-band from the metadata interface. configuration, out-of-band from the metadata interface.
Example SourceMetadata object (which contains two Source objects) Example SourceMetadata object (which contains two Source objects)
that describes which servers the dCDN should use for acquiring that describes which servers the dCDN should use for acquiring
content for the applicable URI path and/or host: content for the applicable URI path and/or host:
{ {
"mandatory-to-enforce": true, "mandatory-to-enforce": true,
skipping to change at page 24, line 20 skipping to change at page 24, line 20
"sources": [ "sources": [
{ {
"generic-metadata-type": "generic-metadata-type":
"application/cdni.Source.v1+json" "application/cdni.Source.v1+json"
"generic-metadata-value": "generic-metadata-value":
{ {
"endpoints": [ "endpoints": [
"a.service123.ucdn.example", "a.service123.ucdn.example",
"b.service123.ucdn.example" "b.service123.ucdn.example"
], ],
"protocol": "HTTP1.1" "protocol": "http1.1"
} }
}, },
{ {
"generic-metadata-type": "generic-metadata-type":
"application/cdni.Source.v1+json" "application/cdni.Source.v1+json"
"generic-metadata-value": "generic-metadata-value":
{ {
"endpoints": ["origin.service123.example"], "endpoints": ["origin.service123.example"],
"protocol": "HTTP1.1" "protocol": "http1.1"
} }
} }
] ]
} }
} }
4.2.1.1. Source 4.2.1.1. Source
A Source object describes the Source which should be used by the dCDN A Source object describes the source to be used by the dCDN for
for content acquisition, e.g., a Surrogate within the uCDN or an content acquisition, e.g., a Surrogate within the uCDN or an
alternate Origin Server, the protocol to be used and any alternate Origin Server, the protocol to be used and any
authentication method. authentication method to be used when contacting that source.
Endpoints within a Source object MUST be treated as equivalent/equal
so a uCDN can specify a list of sources in preference order and for
each source/preference rank a uCDN can specify a list of endpoints
that are equivalent, e.g., a pool of servers that are not behind a
load balancer.
Property: acquisition-auth Property: acquisition-auth
Description: Authentication method to use when requesting Description: Authentication method to use when requesting
content from this source. content from this source.
Type: Auth Type: Auth (see Section 4.2.7)
Mandatory-to-Specify: No. Default is no authentication Mandatory-to-Specify: No. Default is no authentication
required. required.
Property: endpoints Property: endpoints
Description: Origins from which the dCDN can acquire content. Description: Origins from which the dCDN can acquire content.
If multiple endpoints are specified they are all equal, i.e., If multiple endpoints are specified they are all equal, i.e.,
the list is not in preference order, for example a pool of the list is not in preference order, for example a pool of
servers behind a load balancer. servers behind a load balancer.
Type: List of EndPoint objects Type: List of Endpoint objects (See Section 4.3.3)
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: protocol Property: protocol
Description: Network retrieval protocol to use when requesting Description: Network retrieval protocol to use when requesting
content from this source. content from this source.
Type: Protocol Type: Protocol (see Section 4.3.2)
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Example Source object that describes a server the dCDN should use for Example Source object that describes a pair of endpoints (servers)
acquiring content for the applicable URI path and/or host: the dCDN can use for acquiring content for the applicable host and/or
URI path:
{ {
"generic-metadata-type": "application/cdni.Source.v1+json" "generic-metadata-type": "application/cdni.Source.v1+json"
"generic-metadata-value": "generic-metadata-value":
{ {
"endpoints": [ "endpoints": [
"a.service123.ucdn.example", "a.service123.ucdn.example",
"b.service123.ucdn.example" "b.service123.ucdn.example"
], ],
"protocol": "HTTP1.1" "protocol": "http1.1"
} }
} }
4.2.2. LocationACL Metadata 4.2.2. LocationACL Metadata
LocationACL Metadata defines location-based restrictions. LocationACL metadata defines which locations a User Agent needs to be
in, in order to be able to receive the associated content.
A LocationACL which does not include a locations property results in A LocationACL which does not include a locations property results in
an action of allow, meaning that delivery can be performed regardless an action of allow, meaning that delivery can be performed regardless
of the User Agent's location. The action from the first footprint to of the User Agent's location. The action from the first footprint to
match against the User Agent's location is the action a CDN MUST match against the User Agent's location is the action a CDN MUST
take. If two or more footprints overlap, the first footprint that take. If two or more footprints overlap, the first footprint that
matches against the User Agent's location determines the action a CDN matches against the User Agent's location determines the action a CDN
MUST take. If the locations property is included but is empty, or if MUST take. If the locations property is included but is empty, or if
none of the listed footprints matches the User Agent's location, then none of the listed footprints matches the User Agent's location, then
the result is an action of deny. the result is an action of deny.
Although the LocationACL, TimeWindowACL, and ProtocolACL are Although the LocationACL, TimeWindowACL (see Section 4.2.3), and
independent GenericMetadata objects, they may provide conflicting ProtocolACL (see Section 4.2.4) are independent GenericMetadata
information to a dCDN, e.g., a content request which is objects, they may provide conflicting information to a dCDN, e.g., a
simultaneously allowed based on the LocationACL and denied based on content request which is simultaneously allowed based on the
the TimeWindowACL. The dCDN MUST use the logical AND of all ACLs LocationACL and denied based on the TimeWindowACL. The dCDN MUST use
(where 'allow' is true and 'deny' is false) to determine whether or the logical AND of all ACLs (where 'allow' is true and 'deny' is
not a request should be allowed. Thus, in the example given, the false) to determine whether or not a request should be allowed.
request should be denied.
Property: locations Property: locations
Description: Access control list which allows or denies Description: Access control list which allows or denies
(blocks) delivery based on client location. (blocks) delivery based on the User Agent's location.
Type: List of LocationRule objects Type: List of LocationRule objects (see Section 4.2.2.1)
Mandatory-to-Specify: No. Default is allow all locations. Mandatory-to-Specify: No. Default is allow all locations.
Example LocationACL object that allows the dCDN to deliver content to Example LocationACL object that allows the dCDN to deliver content to
any location/IP address: any location/IP address:
{ {
"mandatory-to-enforce": true, "mandatory-to-enforce": true,
"generic-metadata-type": "application/cdni.LocationACL.v1+json" "generic-metadata-type": "application/cdni.LocationACL.v1+json"
"generic-metadata-value": "generic-metadata-value":
{ {
} }
} }
Example LocationACL object (which contains a LocationRule object Example LocationACL object (which contains a LocationRule object
which itself contains a Footprint object) that only allows the dCDN which itself contains a Footprint object) that only allows the dCDN
to deliver content to clients in the USA: to deliver content to User Agents in the USA:
{ {
"mandatory-to-enforce": true, "mandatory-to-enforce": true,
"generic-metadata-type": "application/cdni.LocationACL.v1+json" "generic-metadata-type": "application/cdni.LocationACL.v1+json"
"generic-metadata-value": "generic-metadata-value":
{ {
"locationss": [ "locations": [
{ {
"generic-metadata-type": "generic-metadata-type":
"application/cdni.LocationRule.v1+json" "application/cdni.LocationRule.v1+json"
"generic-metadata-value": "generic-metadata-value":
{ {
"action": "allow", "action": "allow",
"footprints": [ "footprints": [
{
"generic-metadata-type":
"application/cdni.Footprint.v1+json"
"generic-metadata-value":
{ {
"generic-metadata-type": "footprint-type": "countrycode",
"application/cdni.Footprint.v1+json" "footprint-value": ["us"]
"generic-metadata-value":
{
"footprint-type": "countrycode",
"footprint-value": "us"
}
} }
] }
]
} }
} }
] ]
} }
} }
4.2.2.1. LocationRule 4.2.2.1. LocationRule
A LocationRule contains or references a list of Footprint objects and A LocationRule contains or references a list of Footprint objects and
the corresponding action. the corresponding action.
Property: footprints Property: footprints
Description: List of footprints to which the rule applies. Description: List of footprints to which the rule applies.
Type: List of Footprint objects Type: List of Footprint objects (see Section 4.2.2.2)
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: action Property: action
Description: Defines whether the rule specifies locations to Description: Defines whether the rule specifies locations to
allow or deny. allow or deny.
Type: Enumeration [allow|deny] encoded as a lowercase string Type: Enumeration [allow|deny] encoded as a lowercase string
Mandatory-to-Specify: No. Default is deny. Mandatory-to-Specify: No. Default is deny.
Example LocationRule object (which contains a Footprint object) that
allows the dCDN to deliver content to clients in the USA:
{
"generic-metadata-type":
"application/cdni.LocationRule.v1+json"
"generic-metadata-value":
{
"action": "allow",
"footprints": [
{
"generic-metadata-type":
"application/cdni.Footprint.v1+json"
"generic-metadata-value":
{
"footprint-type": "countrycode",
"footprint-value": ["us"]
}
}
]
}
}
4.2.2.2. Footprint 4.2.2.2. Footprint
A Footprint object describes the footprint to which a LocationRule A Footprint object describes the footprint to which a LocationRule
may be applied to, e.g., an IPv4 address range or a geographic may be applied to, e.g., an IPv4 address range or a geographic
location. location.
Property: footprint-type Property: footprint-type
Description: Registered footprint type. The footprint types Description: Registered footprint type. The footprint types
specified by this document are: "ipv4cidr" (IPv4CIDR, see specified by this document are: "ipv4cidr" (IPv4CIDR, see
Section 4.3.7), "ipv6cidr" (IPv6CIDR, see Section 4.3.8), "asn" Section 4.3.5), "ipv6cidr" (IPv6CIDR, see Section 4.3.6), "asn"
(Autonomous System Number, see Section 4.3.9) and "countrycode" (Autonomous System Number, see Section 4.3.7) and "countrycode"
(Country Code, see Section 4.3.10). (Country Code, see Section 4.3.8).
Type: Lowercase String Type: Lowercase String
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: footprint-value Property: footprint-value
Description: Footprint object conforming to the specification Description: List of footprint values conforming to the
associated with the registered footprint type. specification associated with the registered footprint type.
Type: String Type: List of footprints
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
4.2.3. TimeWindowACL Metadata Example Footprint object describing a footprint covering the USA:
TimeWindowACL Metadata defines time-based restrictions. {
"generic-metadata-type":
"application/cdni.Footprint.v1+json"
"generic-metadata-value":
{
"footprint-type": "countrycode",
"footprint-value": ["us"]
}
}
Example Footprint object describing a footprint covering the IP
address ranges 192.0.2.0/24 and 198.51.100.0/24:
{
"generic-metadata-type":
"application/cdni.Footprint.v1+json"
"generic-metadata-value":
{
"footprint-type": "ipv4cidr",
"footprint-value": ["192.0.2.0/24", "198.51.100.0/24"]
}
}
4.2.3. TimeWindowACL
TimeWindowACL metadata defines time-based restrictions.
A TimeWindowACL which does not include a times property results in an A TimeWindowACL which does not include a times property results in an
action of allow, meaning that delivery can be performed regardless of action of allow, meaning that delivery can be performed regardless of
the time of the User Agent's request. The action from the first the time of the User Agent's request. The action from the first
window to match against the current time is the action a CDN MUST window to match against the current time is the action a CDN MUST
take. If two or more windows overlap, the first window that matches take. If two or more windows overlap, the first window that matches
against the current time determines the action a CDN MUST take. If against the current time determines the action a CDN MUST take. If
the times property is included but is empty, or if none of the listed the times property is included but is empty, or if none of the listed
windows matches the current time, then the result is an action of windows matches the current time, then the result is an action of
deny. deny.
Although the LocationACL, TimeWindowACL, and ProtocolACL are Although the LocationACL, TimeWindowACL, and ProtocolACL are
independent GenericMetadata objects, they may provide conflicting independent GenericMetadata objects, they may provide conflicting
information to a dCDN, e.g., a content request which is information to a dCDN, e.g., a content request which is
simultaneously allowed based on the LocationACL and denied based on simultaneously allowed based on the LocationACL and denied based on
the TimeWindowACL. The dCDN MUST use the logical AND of all ACLs the TimeWindowACL. The dCDN MUST use the logical AND of all ACLs
(where 'allow' is true and 'deny' is false) to determine whether or (where 'allow' is true and 'deny' is false) to determine whether or
not a request should be allowed. Thus, in the example given, the not a request should be allowed.
request should be denied.
Property: times Property: times
Description: Description: Access control list which allows or Description: Access control list which allows or denies
denies (blocks) delivery based on request time. (blocks) delivery based on the time of a User Agent's request.
Type: List of TimeWindowRule objects Type: List of TimeWindowRule objects (see Section 4.2.3.1)
Mandatory-to-Specify: No. Default is allow all time windows. Mandatory-to-Specify: No. Default is allow all time windows.
Example TimeWIndowACL object (which contains a TimeWindowRule object
which itself contains a TimeWIndow object) that only allows the dCDN
to deliver content to clients between 09:00AM 01/01/2000 UTC and
17:00AM 01/01/2000 UTC:
{
"mandatory-to-enforce": true,
"generic-metadata-type": "application/cdni.TimeWindowACL.v1+json"
"generic-metadata-value":
{
"times": [
{
"generic-metadata-type":
"application/cdni.TimeWindowRule.v1+json"
"generic-metadata-value":
{
"action": "allow",
"windows": [
{
"generic-metadata-type":
"application/cdni.TimeWindow.v1+json"
"generic-metadata-value":
{
"start": 946717200,
"end": 946746000
}
}
]
}
}
]
}
}
4.2.3.1. TimeWindowRule 4.2.3.1. TimeWindowRule
A TimeWindowRule contains or references a list of TimeWindow objects A TimeWindowRule contains or references a list of TimeWindow objects
and the corresponding action. and the corresponding action.
Property: windows Property: windows
Description: List of time windows to which the rule applies. Description: List of time windows to which the rule applies.
Type: List of TimeWindow objects Type: List of TimeWindow objects (see Section 4.2.3.2)
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: action Property: action
Description: Defines whether the rule specifies time windows to Description: Defines whether the rule specifies time windows to
allow or deny. allow or deny.
Type: Enumeration [allow|deny] encoded as a lowercase string Type: Enumeration [allow|deny] encoded as a lowercase string
Mandatory-to-Specify: No. Default is deny. Mandatory-to-Specify: No. Default is deny.
Example TimeWIndowRule object (which contains a TimeWIndow object)
that only allows the dCDN to deliver content to clients between
09:00AM 01/01/2000 UTC and 17:00AM 01/01/2000 UTC:
{
"generic-metadata-type":
"application/cdni.TimeWindowRule.v1+json"
"generic-metadata-value":
{
"action": "allow",
"windows": [
{
"generic-metadata-type":
"application/cdni.TimeWindow.v1+json"
"generic-metadata-value":
{
"start": 946717200,
"end": 946746000
}
}
]
}
}
4.2.3.2. TimeWindow 4.2.3.2. TimeWindow
A TimeWindow object describes a time range which may be applied by an A TimeWindow object describes a time range which may be applied by an
TimeWindowACL, e.g., start 946717200 (i.e., 09:00AM 01/01/2000 UTC), TimeWindowACL, e.g., start 946717200 (i.e., 09:00AM 01/01/2000 UTC),
end: 946746000 (i.e., 17:00AM 01/01/2000 UTC). end: 946746000 (i.e., 17:00AM 01/01/2000 UTC).
Property: start Property: start
Description: The start time of the window. Description: The start time of the window.
Type: Time Type: Time (see Section 4.3.4)
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: end Property: end
Description: The end time of the window. Description: The end time of the window.
Type: Time Type: Time (see Section 4.3.4)
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Example TimeWIndow object that describes a time window from 09:00AM
01/01/2000 UTC to 17:00AM 01/01/2000 UTC:
{
"generic-metadata-type":
"application/cdni.TimeWindow.v1+json"
"generic-metadata-value":
{
"start": 946717200,
"end": 946746000
}
}
4.2.4. ProtocolACL Metadata 4.2.4. ProtocolACL Metadata
ProtocolACL Metadata defines delivery protocol restrictions. ProtocolACL metadata defines delivery protocol restrictions.
A ProtocolACL which does not include a protocol-acl property results A ProtocolACL which does not include a protocol-acl property results
in an action of allow, meaning that delivery can be performed in an action of allow, meaning that delivery can be performed
regardless of the protocol of the User Agent's request. The action regardless of the protocol of the User Agent's request. The action
from the first protocol to match against the request protocol is the from the first protocol to match against the request protocol is the
action a CDN MUST take. If two or more request protocols overlap, action a CDN MUST take. If two or more request protocols overlap,
the first protocol that matches thre request protocol determines the the first protocol that matches thre request protocol determines the
action a CDN MUST take. If the protocol-acl property is included but action a CDN MUST take. If the protocol-acl property is included but
is empty, or if none of the listed protocol matches the request is empty, or if none of the listed protocol matches the request
protocol, then the result is an action of deny. protocol, then the result is an action of deny.
Although the LocationACL, TimeWindowACL, and ProtocolACL are Although the LocationACL, TimeWindowACL, and ProtocolACL are
independent GenericMetadata objects, they may provide conflicting independent GenericMetadata objects, they may provide conflicting
information to a dCDN, e.g., a content request which is information to a dCDN, e.g., a content request which is
simultaneously allowed based on the ProtocolACL and denied based on simultaneously allowed based on the ProtocolACL and denied based on
the TimeWindowACL. The dCDN MUST use the logical AND of all ACLs the TimeWindowACL. The dCDN MUST use the logical AND of all ACLs
(where 'allow' is true and 'deny' is false) to determine whether or (where 'allow' is true and 'deny' is false) to determine whether or
not a request should be allowed. Thus, in the example given, the not a request should be allowed.
request should be denied.
Property: protocol-acl Property: protocol-acl
Description: Description: Access control list which allows or Description: Description: Access control list which allows or
denies (blocks) delivery based on delivery protocol. denies (blocks) delivery based on delivery protocol.
Type: List of ProtocolRule objects Type: List of ProtocolRule objects (see Section 4.2.4.1)
Mandatory-to-Specify: No. Default is allow all protocols. Mandatory-to-Specify: No. Default is allow all protocols.
Example ProtocolACL object (which contains a ProtocolRule object)
that only allows the dCDN to deliver content using HTTP/1.1:
{
"mandatory-to-enforce": true,
"generic-metadata-type": "application/cdni.ProtocolACL.v1+json"
"generic-metadata-value":
{
"protocol-acl": [
{
"generic-metadata-type":
"application/cdni.ProtocolRule.v1+json"
"generic-metadata-value":
{
"action": "allow",
"protocols": ["http1.1"]
}
}
]
}
}
4.2.4.1. ProtocolRule 4.2.4.1. ProtocolRule
A ProtocolRule contains or references a list of Protocol objects. A ProtocolRule contains or references a list of Protocol objects.
ProtocolRule objects are used to construct a ProtocolACL to apply ProtocolRule objects are used to construct a ProtocolACL to apply
restrictions to content acquisition or delivery. restrictions to content acquisition or delivery.
Property: protocols Property: protocols
Description: List of protocols to which the rule applies. Description: List of protocols to which the rule applies.
Type: List of Protocol objects Type: List of Protocols (see Section 4.3.2)
Mandatory-to-Specify: Yes. Mandatory-to-Specify: Yes.
Property: action Property: action
Description: Defines whether the rule specifies protocols to Description: Defines whether the rule specifies protocols to
allow or deny. allow or deny.
Type: Enumeration [allow|deny] encoded as a lowercase string Type: Enumeration [allow|deny] encoded as a lowercase string
Mandatory-to-Specify: No. Default is deny. Mandatory-to-Specify: No. Default is deny.
Example ProtocolRule object (which contains a ProtocolRule object)
that includes the protocol HTTP/1.1:
{
"generic-metadata-type":
"application/cdni.ProtocolRule.v1+json"
"generic-metadata-value":
{
"action": "allow",
"protocols": ["http1.1"]
}
}
4.2.5. DeliveryAuthorization Metadata 4.2.5. DeliveryAuthorization Metadata
Delivery Authorization defines authorization methods for the delivery Delivery Authorization defines authorization methods for the delivery
of content to User Agents. of content to User Agents.
Property: delivery-auth-methods Property: delivery-auth-methods
Description: Options for authorizing content requests. Description: Options for authorizing content requests.
Delivery for a content request is authorized if any of the Delivery for a content request is authorized if any of the
authorization method in the list is satisfied for that request. authorization methods in the list is satisfied for that
request.
Type: List of Auth objects Type: List of Auth objects (see Section 4.2.7)
Mandatory-to-Specify: No. Default is no authorization Mandatory-to-Specify: No. Default is no authorization
required. required.
4.2.6. Cache 4.2.6. Cache
A Cache object describes the cache control parameters to be applied A Cache object describes the cache control parameters to be applied
to the content by intermediate caches. to the content by intermediate caches.
Property: ignore-query-string Property: ignore-query-string
Description: Allows a cache to ignore URI query string Description: Allows a Surrogate to ignore URI query string
parameters while comparing URIs for equivalence. Matching parameters when comparing the requested URI against the URIs in
against query parameters to ignore MUST be case-insensitive. its cache for equivalence. Matching against query parameters
Each query parameter to ignore is specified in the list. If to ignore MUST be case-insensitive. Each query parameter to
all query parameters should be ignored, then the list MUST be ignore is specified in the list. If all query parameters
specified and MUST be empty. should be ignored, then the list MUST be specified and MUST be
empty.
Type: List of String Type: List of String
Mandatory-to-Specify: No. Default is to consider query string Mandatory-to-Specify: No. Default is to consider query string
parameters when comparing URIs. parameters when comparing URIs.
4.2.7. Grouping Example Cache object that instructs the dCDN to ignore all query
parameters:
{
"generic-metadata-type":
"application/cdni.Cache.v1+json"
"generic-metadata-value":
{
"ignore-query-string": []
}
}
Example Cache object that instructs the dCDN to ignore the (case-
insensitive) query parameters named "sessionid" and "random":
{
"generic-metadata-type":
"application/cdni.Cache.v1+json"
"generic-metadata-value":
{
"ignore-query-string": ["sessionid", "random"]
}
}
4.2.7. Auth
An Auth object defines authentication and authorization methods to be
used during content acquisition and content delivery, respectively.
Property: auth-type
Description: Registered Auth type (see Section 4.2.7.1 and
Section 7.3).
Type: String
Mandatory-to-Specify: Yes.
Property: auth-value
Description: An object conforming to the specification
associated with the Registered Auth type.
Type: GenericMetadata Object
Mandatory-to-Specify: Yes.
Example Auth object (which contains a BasicAuth object, see
Section 4.2.7.1):
{
"generic-metadata-type":
"application/cdni.Auth.v1+json"
"generic-metadata-value":
{
"auth-type": "httpbasic",
"auth-value":
{
"generic-metadata-type":
"application/cdni.BasicAuth.v1+json"
"generic-metadata-value":
{
"username": "user",
"password": "pass"
}
}
}
}
4.2.7.1. BasicAuth
BasicAuth is a Registered Auth type defining an object for
encapsulating user credentials (i.e., username and password) for use
with HTTP Basic Authentication (see Section 7.3). The BasicAuth
object contains the following properties:
Property: username
Description: Identification of user.
Type: String
Mandatory-to-Specify: Yes.
Property: password
Description: Password for user identified by username property.
Type: String
Mandatory-to-Specify: Yes.
Example BasicAuth object containing the username "user" and password
"pass":
{
"generic-metadata-type":
"application/cdni.BasicAuth.v1+json"
"generic-metadata-value":
{
"username": "user",
"password": "pass"
}
}
4.2.8. Grouping
A Grouping object identifies a large group of content to which a A Grouping object identifies a large group of content to which a
given asset belongs. given asset belongs.
Property: ccid Property: ccid
Description: Content Collection identifier for an application- Description: Content Collection identifier for an application-
specific purpose such as logging. specific purpose such as logging.
Type: String Type: String
skipping to change at page 32, line 30 skipping to change at page 38, line 5
Property: sid Property: sid
Description: Session identifier for an application-specific Description: Session identifier for an application-specific
purpose such as logging. purpose such as logging.
Type: String Type: String
Mandatory-to-Specify: No. Default is an empty string. Mandatory-to-Specify: No. Default is an empty string.
Example Grouping object that specifies a Content Collection
Identifier and a Session identifier for the content associated with
the Grouping object's parent HostMetdata or PathMetadata:
{
"generic-metadata-type":
"application/cdni.Grouping.v1+json"
"generic-metadata-value":
{
"ccid": "ABCD",
"sid": "EFGH"
}
}
4.3. CDNI Metadata Simple Data Type Descriptions 4.3. CDNI Metadata Simple Data Type Descriptions
This section describes the simple data types that are used for This section describes the simple data types that are used for
properties of CDNI Metadata objects. properties of CDNI metadata objects.
4.3.1. Link 4.3.1. Link
A link object may be used in place of any of the objects or A Link object may be used in place of any of the objects or
properties described above. Links can be used to avoid duplication properties described above. Link objects can be used to avoid
if the same metadata information is repeated within the metadata duplication if the same metadata information is repeated within the
tree. When a link replaces an object, its href property is set to metadata tree. When a Link object replaces another object, its href
the URI of the resource and its type property is set to the type of property is set to the URI of the resource and its type property is
the object it is replacing. set to the Media Type of the object it is replacing.
dCDNs can detect the presence of a Link object instead of another
metadata object by detecting the presence of a property named "href"
within the object. This measn that GenericMetadata types MUST NOT
contain a property named "href" because doing so would conflict with
the ability for dCDNs to detect Link objects being used to reference
a GenericMetadata object.
Property: href Property: href
Description: The URI of the addressable object being Description: The URI of the addressable object being
referenced. referenced.
Type: URI Type: String
Mandatory-to-Specify: Yes Mandatory-to-Specify: Yes
Property: type Property: type
Description: The type of the object being referenced. Description: The type of the object being referenced.
Type: String Type: String
Mandatory-to-Specify: No Mandatory-to-Specify: No
Example Link object referencing a HostMetadata object:
{
"type": "application/cdni.HostMetadata.v1+json",
"href": "http://metadata.ucdn.example/host1234"
}
4.3.2. Protocol 4.3.2. Protocol
Protocol objects are used to specify registered protocols for content Protocol objects are used to specify registered protocols for content
acquisition or delivery (see Section 7.2). acquisition or delivery (see Section 7.2).
Type: String Type: String
Example:
"http1.1"
4.3.3. Endpoint 4.3.3. Endpoint
A hostname (with optional port) or an IP address (with optional A Hostname (with optional port) or an IP address (with optional
port). port).
Note: All implementations MUST support IPv4 addresses encoded as Note: All implementations MUST support IPv4 addresses encoded as
specified by the 'IPv4address' rule in Section 3.2.2 of [RFC3986] and specified by the 'IPv4address' rule in Section 3.2.2 of [RFC3986].
MUST support all IPv6 address formats specified in [RFC4291]. Server IPv6 addresses MUST be encoded in one of the IPv6 address formats
implementations SHOULD use IPv6 address formats specified in specified in [RFC5952] although receivers MUST support all IPv6
[RFC5952]. address formats specified in [RFC4291].
Type: String
4.3.4. URI
A URI as specified in [RFC3986].
Type: String Type: String
4.3.5. Time Example Hostname:
A time value expressed in seconds since Unix epoch in the UTC
timezone.
Type: Integer
4.3.6. Auth
An Auth object defines authentication and authorization methods to be
used during content acquisition and content delivery, respectively.
Property: auth-type
Description: Registered Auth type (see Section 4.3.6.1 and
Section 7.3).
Type: String
Mandatory-to-Specify: Yes.
Property: auth-value
Description: An object conforming to the specification
associated with the Registered Auth type.
Type: String
Mandatory-to-Specify: Yes.
4.3.6.1. CredentialAuth Type "http://metadata.ucdn.example/host1234"
CredentialAuth is a Registered Auth type defining an object for Example IPv4 address:
encapsulating user credentials (i.e., username and password) (see
Section 7.3). The CredentialAuth object contains the following
properties:
Property: username "192.0.2.1"
Description: Identification of user. Example IPv6 address (with port number):
Type: String "[2001:db8::1]:81"
Mandatory-to-Specify: Yes. 4.3.4. Time
Property: password A time value expressed in seconds since Unix epoch in the UTC
timezone.
Description: Password for user identified by username property. Type: Integer
Type: String Example Time representing 09:00AM 01/01/2000 UTC:
Mandatory-to-Specify: Yes. 946717200
4.3.7. IPv4CIDR 4.3.5. IPv4CIDR
An IPv4address CIDR block encoded as specified by the 'IPv4address' An IPv4address CIDR block encoded as specified by the 'IPv4address'
rule in Section 3.2.2 of [RFC3986] followed by a / followed by an rule in Section 3.2.2 of [RFC3986] followed by a / followed by an
unsigned integer representing the leading bits of the routing prefix unsigned integer representing the leading bits of the routing prefix
(i.e. IPv4 CIDR notation). Single IP addresses can be expressed as (i.e. IPv4 CIDR notation). Single IP addresses can be expressed as
/32. /32.
Type: String Type: String
4.3.8. IPv6CIDR Example IPv4 CIDR:
"192.0.2.0/24"
4.3.6. IPv6CIDR
An IPv6address CIDR block encoded in one of the IPv6 address formats An IPv6address CIDR block encoded in one of the IPv6 address formats
specified in [RFC5952] followed by a / followed by an unsigned specified in [RFC5952] followed by a / followed by an unsigned
integer representing the leading bits of the routing prefix (i.e. integer representing the leading bits of the routing prefix (i.e.
IPv6 CIDR notation). Single IP addresses can be expressed as /128. IPv6 CIDR notation). Single IP addresses can be expressed as /128.
Type: String Type: String
4.3.9. ASN Example IPv6 CIDR:
"2001:db8::/32"
4.3.7. ASN
An Autonomous System Number encoded as a string consisting of the An Autonomous System Number encoded as a string consisting of the
characters AS (in uppercase) followed by the Autonomous System characters "as" (in lowercase) followed by the Autonomous System
number. For example "AS64496". number.
Type: String Type: String
4.3.10. CountryCode Example ASN:
"as64496"
4.3.8. CountryCode
An ISO 3166-1 alpha-2 code [ISO3166-1] in lowercase. An ISO 3166-1 alpha-2 code [ISO3166-1] in lowercase.
Type: String Type: String
Example Country Code representing the USA:
"us"
5. CDNI Metadata Capabilities 5. CDNI Metadata Capabilities
CDNI Metadata is used to convey information pertaining to content CDNI metadata is used to convey information pertaining to content
delivery from uCDN to dCDN. For optional metadata, it may be useful delivery from uCDN to dCDN. For optional metadata, it may be useful
for the uCDN to know if the dCDN supports the metadata, prior to for the uCDN to know if the dCDN supports the underlying
delegating any content requests to the dCDN. If optional-to- functionality described by the metadata, prior to delegating any
implement metadata is "mandatory-to-enforce", and the dCDN does not content requests to the dCDN. If some metadata is "mandatory-to-
support it, any delegated requests for that content will fail. The enforce", and the dCDN does not support it, any delegated requests
uCDN will likely want to avoid delegating those requests to that for content that requires that metadata will fail. The uCDN will
dCDN. Likewise, for any metadata which may be assigned optional likely want to avoid delegating those requests to that dCDN.
values, it may be useful for the uCDN to know which values a dCDN Likewise, for any metadata which may be assigned optional values, it
supports, prior to delegating any content requests to that dCDN. If may be useful for the uCDN to know which values a dCDN supports,
the optional value assigned to a given piece of content's metadata is prior to delegating any content requests to that dCDN. If the
not supported by the dCDN, any delegated requests for that content optional value assigned to a given piece of content's metadata is not
may fail, so again the uCDN is likely to want to avoid delegating supported by the dCDN, any delegated requests for that content may
those requests to that dCDN. fail, so again the uCDN is likely to want to avoid delegating those
requests to that dCDN.
The CDNI Footprint and Capabilities Interface (FCI) [RFC7336] The CDNI Footprint and Capabilities Interface (FCI) [RFC7336]
provides a means of advertising capabilities from dCDN to uCDN. provides a means of advertising capabilities from dCDN to uCDN.
Support for optional metadata and support for optional metadata Support for optional metadata and support for optional metadata
values may be advertised using the FCI. values may be advertised using the FCI.
6. CDNI Metadata interface 6. CDNI Metadata interface
This section specifies an interface to enable a dCDN to retrieve CDNI This section specifies an interface to enable a dCDN to retrieve CDNI
Metadata objects from a uCDN. metadata objects from a uCDN.
The interface can be used by a dCDN to retrieve CDNI Metadata objects The interface can be used by a dCDN to retrieve CDNI metadata objects
either: either:
o Dynamically as required by the dCDN to process received requests. o Dynamically as required by the dCDN to process received requests.
For example in response to a query from an uCDN over the CDNI For example in response to a query from an uCDN over the CDNI
Request Routing Redirection interface (RI) Request Routing Redirection interface (RI)
[I-D.ietf-cdni-redirection] or in response to receiving a request [I-D.ietf-cdni-redirection] or in response to receiving a request
for content from a User Agent. Or; for content from a User Agent. Or;
o In advance of being required. For example in the case of pre- o In advance of being required. For example in the case of pre-
positioned CDNI Metadata acquisition. positioned CDNI metadata acquisition.
The CDNI Metadata interface is built on the principles of RESTful web The CDNI metadata interface is built on the principles of HTTP web
services. In particular, this means that requests and responses over services. In particular, this means that requests and responses over
the interface are built around the transfer of representations of the interface are built around the transfer of representations of
hyperlinked resources. A resource in the context of the CDNI hyperlinked resources. A resource in the context of the CDNI
Metadata interface is any object in the Data Model (as described in metadata interface is any object in the object model (as described in
Section 3 and Section 4). Section 3 and Section 4).
To retrieve CDNI metadata, a CDNI Metadata client (i.e., a client in To retrieve CDNI metadata, a CDNI metadata client (i.e., a client in
the dCDN) first makes a HTTP GET request for the URI of the HostIndex the dCDN) first makes a HTTP GET request for the URI of the HostIndex
which provides the CDNI Metadata client with a list of Hostnames for which provides the CDNI metadata client with a list of Hostnames for
which the uCDN may delegate content delivery to the dCDN. The CDNI which the uCDN may delegate content delivery to the dCDN. The CDNI
Metadata client can then obtain any other CDNI Metadata objects by metadata client can then obtain any other CDNI metadata objects by
making a HTTP GET requests for any linked Metadata objects it making a HTTP GET requests for any linked metadata objects it
requires. requires.
CDNI Metadata servers (i.e., servers in the uCDN) are free to assign CDNI metadata servers (i.e., servers in the uCDN) are free to assign
whatever structure they desire to the URIs for CDNI Metadata objects whatever structure they desire to the URIs for CDNI metadata objects
and CDNI Metadata clients MUST NOT make any assumptions regarding the and CDNI metadata clients MUST NOT make any assumptions regarding the
structure of CDNI Metadata URIs or the mapping between CDNI Metadata structure of CDNI metadata URIs or the mapping between CDNI metadata
objects and their associated URIs. Therefore any URIs present in the objects and their associated URIs. Therefore any URIs present in the
examples below are purely illustrative and are not intended to impose examples in this document are purely illustrative and are not
a definitive structure on CDNI Metadata interface implementations. intended to impose a definitive structure on CDNI metadata interface
implementations.
6.1. Transport 6.1. Transport
The CDNI Metadata interface uses HTTP as the underlying protocol The CDNI metadata interface uses HTTP as the underlying protocol
transport. transport.
The HTTP Method in the request defines the operation the request The HTTP Method in the request defines the operation the request
would like to perform. A server implementation of the CDNI Metadata would like to perform. A server implementation of the CDNI metadata
interface MUST support the HTTP GET and HEAD methods. interface MUST support the HTTP GET and HEAD methods.
The corresponding HTTP Response returns the status of the operation The corresponding HTTP Response returns the status of the operation
in the HTTP Status Code and returns the current representation of the in the HTTP Status Code and returns the current representation of the
resource (if appropriate) in the Response Body. HTTP Responses from resource (if appropriate) in the Response Body. HTTP Responses from
servers implementing the CDNI Metadata interface that contain a servers implementing the CDNI metadata interface that contain a
response body SHOULD include an ETag to enable validation of cached response body SHOULD include an ETag to enable validation of cached
versions of returned resources. versions of returned resources.
The CDNI Metadata interface specified in this document is a read-only The CDNI metadata interface specified in this document is a read-only
interface. Therefore support for other HTTP methods such as PUT, interface. Therefore support for other HTTP methods such as PUT,
POST and DELETE etc. is not specified. A server implementation of POST and DELETE etc. is not specified. A server implementation of
the CDNI Metadata interface SHOULD reject all methods other than GET the CDNI metadata interface SHOULD reject all methods other than GET
and HEAD. and HEAD.
As the CDNI Metadata interface builds on top of HTTP, CDNI Metadata As the CDNI metadata interface builds on top of HTTP, CDNI metadata
server implementations MAY make use of any HTTP feature when server implementations MAY make use of any HTTP feature when
implementing the CDNI Metadata interface, for example a CDNI Metadata implementing the CDNI metadata interface, for example a CDNI metadata
server MAY make use of HTTP's caching mechanisms to indicate that the server MAY make use of HTTP's caching mechanisms to indicate that the
returned response/representation can be reused without re-contacting returned response/representation can be reused without re-contacting
the CDNI Metadata server. the CDNI metadata server.
6.2. Retrieval of CDNI Metadata resources 6.2. Retrieval of CDNI Metadata resources
In the general case a CDNI Metadata server makes each instance of an In the general case a CDNI metadata server makes CDNI metadata
addressable CDNI Metadata object available via a unique URI and objects available via a unique URIs and therefore in order to
therefore in order to retrieve CDNI Metadata, a CDNI Metadata client retrieve CDNI metadata, a CDNI metadata client first makes a HTTP GET
first makes a HTTP GET request for the URI of the HostIndex which request for the URI of the HostIndex which provides the CDNI metadata
provides the CDNI Metadata client with a list of Hostnames for which client with a list of Hostnames for which the uCDN may delegate
the uCDN may delegate content delivery to the dCDN. content delivery to the dCDN.
In order to retrieve the CDNI Metadata for a particular request the In order to retrieve the CDNI metadata for a particular request the
CDNI Metadata client processes the received HostIndex object and CDNI metadata client processes the received HostIndex object and
finds the corresponding HostMetadata entry (by matching the hostname finds the corresponding HostMetadata entry (by matching the hostname
in the request against the hostnames listed in the HostMatch in the request against the hostnames listed in the HostMatch
objects). If the HostMetadata is linked (rather than embedded), the objects). If the HostMetadata is linked (rather than embedded), the
CDNI metadata client then makes a GET request for the URI specified CDNI metadata client then makes a GET request for the URI specified
in the href property of the Link object which points to the in the href property of the Link object which points to the
HostMetadata object itself. HostMetadata object itself.
In order to retrieve the most specific metadata for a particular In order to retrieve the most specific metadata for a particular
request, the CDNI metadata client inspects the HostMetadata for request, the CDNI metadata client inspects the HostMetadata for
references to more specific PathMetadata objects (by matching the URI references to more specific PathMetadata objects (by matching the URI
path in the request against the path-patterns in the PathMatch). If path in the request against the path-patterns in the PathMatch). If
any PathMetadata match the request (and are linked rather than any PathMetadata match the request (and are linked rather than
embedded), the CDNI metadata client makes another GET request for the embedded), the CDNI metadata client makes another GET request for the
PathMetadata. Each PathMetadata object may also include references PathMetadata. Each PathMetadata object may also include references
to yet more specific metadata. If this is the case, the CDNI to yet more specific metadata. If this is the case, the CDNI
metadata client continues requesting PathMatch and PathMetadata metadata client continues requesting PathMatch and PathMetadata
objects recursively. objects recursively. The CDNI metadata client repeats this approach
of processing metadata objects and retrieving (via HTTP GETs) any
linked objects until it has all the metadata objects it requires in
order to process a redirection request from an uCDN or a content
request from a User Agent.
In cases where a dCDN is not able to retrieve the entire set of CDNI In cases where a dCDN is not able to retrieve the entire set of CDNI
metadata associated with a User Agent request, for example because metadata associated with a User Agent request, for example because
the uCDN is uncontactable or returns an HTTP 4xx or 5xx status in the uCDN is uncontactable or returns an HTTP 4xx or 5xx status in
response to some or all of the dCDN's CDNI metadata requests, the response to some or all of the dCDN's CDNI metadata requests, the
dCDN MUST NOT serve the requested content unless the dCDN has stale dCDN MUST NOT serve the requested content unless the dCDN has stale
versions of all the required metadata and the stale-if-error Cache- versions of all the required metadata and the stale-if-error Cache-
Control extension [RFC5861] was included in all previous responses Control extension [RFC5861] was included in all previous responses
that are required but cannot currently be retrieved. The dCDN can that are required but cannot currently be retrieved. The dCDN can
continue to serve other content for which it can retrieve (or for continue to serve other content for which it can retrieve (or for
skipping to change at page 38, line 26 skipping to change at page 44, line 17
Where a dCDN is interconnected with multiple uCDNs, the dCDN needs to Where a dCDN is interconnected with multiple uCDNs, the dCDN needs to
determine which uCDN's CDNI metadata should be used to handle a determine which uCDN's CDNI metadata should be used to handle a
particular User Agent request. particular User Agent request.
When application level redirection (e.g., HTTP 302 redirects) is When application level redirection (e.g., HTTP 302 redirects) is
being used between CDNs, it is expected that the dCDN will be able to being used between CDNs, it is expected that the dCDN will be able to
determine the uCDN that redirected a particular request from determine the uCDN that redirected a particular request from
information contained in the received request (e.g., via the URI). information contained in the received request (e.g., via the URI).
With knowledge of which uCDN routed the request, the dCDN can choose With knowledge of which uCDN routed the request, the dCDN can choose
the correct metadata server from which to obtain the HostIndex. Note the correct uCDN from which to obtain the HostIndex. Note that the
that the HostIndex served by each uCDN may be unique. HostIndex served by each uCDN may be unique.
In the case of DNS redirection there is not always sufficient In the case of DNS redirection there is not always sufficient
information carried in the DNS request from User Agents to determine information carried in the DNS request from User Agents to determine
the uCDN that redirected a particular request (e.g., when content the uCDN that redirected a particular request (e.g., when content
from a given host is redirected to a given dCDN by more than one from a given host is redirected to a given dCDN by more than one
uCDN) and therefore dCDNs may have to apply local policy when uCDN) and therefore dCDNs may have to apply local policy when
deciding which uCDN's metadata to apply. deciding which uCDN's metadata to apply.
6.3. Bootstrapping 6.3. Bootstrapping
The URI for the HostIndex object of a given uCDN needs to be either The URI for the HostIndex object of a given uCDN needs to be either
configured in, or discovered by, the dCDN. All other objects/ configured in, or discovered by, the dCDN. All other objects/
resources are then discoverable from the HostIndex object by resources are then discoverable from the HostIndex object by
following the links in the HostIndex object and the referenced following any links in the HostIndex object and the referenced
HostMetadata and PathMetadata objects. HostMetadata and PathMetadata objects and their GenericMetadata sub-
objects.
If the URI for the HostIndex object is not manually configured in the If the URI for the HostIndex object is not manually configured in the
dCDN then the HostIndex URI could be discovered. A mechanism dCDN then the HostIndex URI could be discovered. A mechanism
allowing the dCDN to discover the URI of the HostIndex is outside the allowing the dCDN to discover the URI of the HostIndex is outside the
scope of this document. scope of this document.
6.4. Encoding 6.4. Encoding
Objects are resources that may be: CDNI metadata objects MUST be encoded as I-JSON objects [RFC7493]
containing a dictionary of (key,value) pairs where the keys are the
property names and the values are the associated property values.
o Addressable, where the object is a resource that may be retrieved The keys of the dictionary are the names of the properties associated
or referenced via its own URI. with the object and are therefore dependent on the specific object
being encoded (i.e., dependent on the Media Type of the returned
resource). Likewise, the values associated with each property
(dictionary key) are dependent on the specific object being encoded
(i.e., dependent on the Media Type of the returned resource).
o Embedded, where the object is contained within a property of an Dictionary keys (properties) in I-JSON are case sensitive. By
addressable object. convention any dictionary key (property) defined by this document
(for example the names of CDNI metadata object properties) MUST be
represented in lowercase.
The descriptions of objects use the phrase "X contains Y" to mean 6.5. Extensibility
that Y is either directly embedded in X or is linked to by X. It is
generally a deployment choice for the uCDN implementation to decide
when and which CDNI Metadata objects to embed and which are made
separately addressable.
6.4.1. MIME Media Types The set of GenericMetadata objects may be extended with additional
(standards based or vendor specific) metadata objects through the
specification of new GenericMetadata objects. The GenericMetadata
object defined in Section 4.1.7 specifies a type field and a type-
specific value field that allows any metadata to be included in
either the HostMetadata or PathMetadata lists.
All MIME media types for CDNI Metadata objects are prefixed with As with the initial GenericMetadata types defined in Section 4.2,
"application/cdni.". The MIME media type for each object then future GenericMetadata types MUST specify the information necessary
contains the object name of that object as defined by this document. for constructing and decoding the GenericMetadata object.
The object type name is followed by ".v" and the version number of
the object type (e.g., ".v1"). Finally, the encoding type "+json" is Any document which defines a new GenericMetadata type SHOULD:
appended. Table 4 lists the MIME media type for the metadata objects
1. Specify the Media Type used to identify the new GenericMetadata
type being specified.
2. Define the set of properties associated with the new type
contained within the GenericMetadata object. GenericMetadata
types MUST NOT contain a property named "href" because doing so
would conflict with the ability for dCDNs to detect Link objects
being used to reference a GenericMetadata object.
3. For each property, define a name, description, type, and whether
or not the property is mandatory-to-specify.
4. Describe the semantics of the new type including its purpose and
example of a use case to which it applies including an example
encoded in I-JSON.
Note: In the case of vendor specific extensions, identification
within the type name defined for a GenericMetadata object, of the
organization that defined the new GenericMetadata object decreases
the possibility of GenericMetadata type collisions.
6.6. Metadata Enforcement
At any given time, the set of GenericMetadata types supported by the
uCDN may not match the set of GenericMetadata types supported by the
dCDN.
In the cases where a uCDN sends metadata containing a GenericMetadata
type that a dCDN does not support, the dCDN MUST enforce the
semantics of the "mandatory-to-enforce" property. If a dCDN does not
understand or is unable to perform the functions associated with any
"mandatory-to-enforce" metadata, the dCDN MUST NOT service any
requests for the corresponding content.
Note: Ideally, uCDNs would not delegate content requests to a dCDN
which does not support the "mandatory-to-enforce" metadata associated
with the content being requested. However, even if the uCDN has a
priori knowledge of the metadata supported by the dCDN (e.g., via the
CDNI capabilities interface or through out-of-band negotiation
between CDN operators) metadata support may fluctuate or be
inconsistent (e.g., due to mis-communication, mis-configuration, or
temporary outage). Thus, the dCDN MUST always evaluate all metadata
associated with redirection requests and content requests and reject
any requests where "mandatory-to-enforce" metadata associated with
the content cannot be enforced.
6.7. Metadata Conflicts
It is possible that new metadata definitions may obsolete or conflict
with existing GenericMetadata (e.g., a future revision of the CDNI
metadata interface may redefine the Auth GenericMetadata object or a
custom vendor extension may implement an alternate Auth metadata
option). If multiple metadata (e.g., cdni.Auth.v2, vendor1.Auth, and
vendor2.Auth) all conflict with an existing GenericMetadata object
(e.g., cdni.Auth) and all are marked as "mandatory-to-enforce", it
may be ambiguous which metadata should be applied, especially if the
functionality of the metadata overlap.
As described in Section 3.3, metadata override only applies to
metadata objects of the same exact type, found in HostMetadata and
nested PathMetadata structures. The CDNI metadata interface does not
support enforcement of dependencies between different metadata types.
It is the responsibility of the CSP and the CDN operators to ensure
that metadata assigned to a given content do not conflict.
Note: Because metadata is inherently ordered in GenericMetadata
lists, as well as in the PathMetadata hierarchy and PathMatch lists,
multiple conflicting metadata types MAY be used, however, metadata
hierarchies MUST ensure that independent PathMatch root objects are
used to prevent ambiguous or conflicting metadata definitions.
6.8. Versioning
The version of CDNI metadata objects is conveyed inside the Media
Type that is included in the HTTP Content-Type header. Upon
responding to a request for an object, a CDNI metadata server MUST
include a Content-Type header with the Media Type containing the
version number of the object. HTTP requests sent to a metadata
server SHOULD include an Accept header with the Media Type (which
includes the version) of the expected object. Metadata clients can
specify multiple Media Types in the Accept header, for example if a
metadata client is capable of processing two different versions of
the same type of object (defined by different Media Types) it may
decide to include both in the Accept header. The version of each
object defined by this document is version 1. For example: "Content-
Type: application/cdni.HostIndex.v1+json".
GenericMetadata objects include a "type" property which specifies the
Media Type of the GenericMetadata value. This Media Type should also
include a version. Any document which defines a new GenericMetadata
type MUST specify the version number which it describes. For
example: "application/cdni.Location.v1+json".
6.9. Media Types
All Media Types for CDNI metadata objects are prefixed with
"application/cdni.". The Media Type for each object then contains
the object name of that object as defined by this document. The
object type name is followed by ".v" and the version number of the
object type (e.g., ".v1"). Finally, the encoding type "+json" is
appended. Table 4 lists the Media Type for the metadata objects
(resources) that are specified in this document. (resources) that are specified in this document.
+-----------------------+-------------------------------------------+ +-----------------------+-------------------------------------------+
| Data Object | MIME Media Type | | Data Object | MIME Media Type |
+-----------------------+-------------------------------------------+ +-----------------------+-------------------------------------------+
| HostIndex | application/cdni.HostIndex.v1+json | | HostIndex | application/cdni.HostIndex.v1+json |
| HostMatch | application/cdni.HostMatch.v1+json | | HostMatch | application/cdni.HostMatch.v1+json |
| HostMetadata | application/cdni.HostMetadata.v1+json | | HostMetadata | application/cdni.HostMetadata.v1+json |
| PathMatch | application/cdni.PathMatch.v1+json | | PathMatch | application/cdni.PathMatch.v1+json |
| PatternMatch | application/cdni.PatternMatch.v1+json | | PatternMatch | application/cdni.PatternMatch.v1+json |
skipping to change at page 40, line 30 skipping to change at page 48, line 30
| TimeWindowACL | application/cdni.TimeWindowACL.v1+json | | TimeWindowACL | application/cdni.TimeWindowACL.v1+json |
| TimeWindowRule | application/cdni.TimeWindowRule.v1+json | | TimeWindowRule | application/cdni.TimeWindowRule.v1+json |
| TimeWindow | application/cdni.TineWindow.v1+json | | TimeWindow | application/cdni.TineWindow.v1+json |
| ProtocolACL | application/cdni.ProtocolACL.v1+json | | ProtocolACL | application/cdni.ProtocolACL.v1+json |
| ProtocolRule | application/cdni.ProtocolRule.v1+json | | ProtocolRule | application/cdni.ProtocolRule.v1+json |
| DeliveryAuthorization | application/ | | DeliveryAuthorization | application/ |
| | cdni.DeliveryAuthorization.v1+json | | | cdni.DeliveryAuthorization.v1+json |
| Cache | application/cdni.Cache.v1+json | | Cache | application/cdni.Cache.v1+json |
| Grouping | application/cdni.Grouping.v1+json | | Grouping | application/cdni.Grouping.v1+json |
| Auth | application/cdni.Auth.v1+json | | Auth | application/cdni.Auth.v1+json |
| CredentialsAuth | application/cdni.CredentialAuth.v1+json | | BasicAuth | application/cdni.BasicAuth.v1+json |
+-----------------------+-------------------------------------------+ +-----------------------+-------------------------------------------+
Table 4: MIME Media Types for CDNI Metadata objects Table 4: MIME Media Types for CDNI Metadata objects
6.4.2. I-JSON Encoding of Objects 6.10. Complete CDNI Metadata Example
A CDNI Metadata object is encoded as an I-JSON object [RFC7492]
containing a dictionary of (key,value) pairs where the keys are the
property names and the values are the associated property values.
The keys of the dictionary are the names of the properties associated
with the object and are therefore dependent on the specific object
being encoded (i.e., dependent on the MIME Media Type of the returned
resource). Likewise, the values associated with each key are
dependent on the specific object being encoded (i.e., dependent on
the MIME Media Type of the returned resource).
Dictionary keys in JSON are case sensitive. By convention any
dictionary key defined by this document (for example the names of
CDNI Metadata object properties) MUST be represented in lowercase.
In addition to the properties specified for each object type, the
keys defined below may be present in any object.
Key: base
Description: Provides a prefix for any relative URLs in the
object. This is similar to the XML base tag [XML-BASE]. If
absent, all URLs in the remainder of the response MUST be
absolute URLs.
Type: URI
Mandatory: No
Key: _links
Description: The links from this object to other addressable
objects. Any property whose value is an object may be replaced
by a link to an object with the same type as the property it
replaces. The keys of the _links dictionary are the names of
the properties being replaced. The values of the dictionary
are Link objects with href set to the URI of the object and
type set to the MIME media type of the object being replaced.
Type: Dictionary object of Link objects
Mandatory: No
6.4.2.1. Encoded CDNI Metadata Example
A dCDN may request the HostIndex and receive the following object of A dCDN may request the HostIndex and receive the following object of
type "application/cdni.HostIndex.v1+json": type "application/cdni.HostIndex.v1+json":
{ {
"hosts": [ "hosts": [
{ {
"host": "video.example.com", "host": "video.example.com",
"_links": { "_links": {
"host-metadata" : { "host-metadata" : {
skipping to change at page 42, line 48 skipping to change at page 49, line 48
"generic-metadata-value": { "generic-metadata-value": {
"sources": [ "sources": [
{ {
"_links": { "_links": {
"acquisition-auth": { "acquisition-auth": {
"auth-type": "application/cdni.Auth.v1+json", "auth-type": "application/cdni.Auth.v1+json",
"href": "http://metadata.ucdn.example/auth1234" "href": "http://metadata.ucdn.example/auth1234"
} }
}, },
"endpoint": "acq1.ucdn.example", "endpoint": "acq1.ucdn.example",
"protocol": "HTTP1.1" "protocol": "http1.1"
}, },
{ {
"_links": { "_links": {
"acquisition-auth": { "acquisition-auth": {
"auth-type": "application/cdni.Auth.v1+json", "auth-type": "application/cdni.Auth.v1+json",
"href": "http://metadata.ucdn.example/auth1234" "href": "http://metadata.ucdn.example/auth1234"
} }
}, },
"endpoint": "acq2.ucdn.example", "endpoint": "acq2.ucdn.example",
"protocol": "HTTP1.1" "protocol": "http1.1"
} }
] ]
} }
}, },
{ {
"generic-metadata-type": "generic-metadata-type":
"application/cdni.LocationACL.v1+json", "application/cdni.LocationACL.v1+json",
"generic-metadata-value": { "generic-metadata-value": {
"locations": [ "locations": [
{ {
skipping to change at page 43, line 38 skipping to change at page 50, line 38
] ]
} }
}, },
{ {
"generic-metadata-type": "generic-metadata-type":
"application/cdni.ProtocolACL.v1+json", "application/cdni.ProtocolACL.v1+json",
"generic-metadata-value": { "generic-metadata-value": {
"protocol-acl": [ "protocol-acl": [
{ {
"protocols": [ "protocols": [
"HTTP1.1" "http1.1"
], ],
"action": "allow" "action": "allow"
} }
] ]
} }
} }
], ],
"paths": [ "paths": [
{ {
"path-pattern": { "path-pattern": {
skipping to change at page 45, line 25 skipping to change at page 52, line 25
"end": "1327393200" "end": "1327393200"
} }
], ],
"action": "allow" "action": "allow"
] ]
} }
} }
] ]
} }
6.5. Extensibility
The set of property Metadata may be extended with additional
(standards based or vendor specific) property Metadata through the
specification of new GenericMetadata objects. The GenericMetadata
object defined in Section 4.1.7 specifies a type field and a type-
specific value field that allows any Metadata property to be included
in either the HostMetadata or PathMetadata lists.
As with the initial GenericMetadata types defined in Section 4.2,
future GenericMetadata types MUST specify the information necessary
for constructing and decoding the GenericMetadata object. This
information includes the list of properties contained within the
GenericMetadata object, and for each property, the specification
should include a description, a type, and whether or not the given
property is mandatory-to-specify.
Any document which defines a new GenericMetadata type has to:
1. Specify the MIME Media Type used to identify the new
GenericMetadata type being specified.
2. Define the set of properties associated with the new type.
3. For each property, define a name, description, type, and whether
or not the property is mandatory-to-specify.
4. Describe the semantics of the new type including its purpose and
example of a use case to which it applies.
Note: Identification, within the type name defined for a property
Metadata object, of the organization that defined the extension
property Metadata decreases the possibility of property Metadata type
collisions.
6.6. Metadata Enforcement
At any given time, the set of GenericMetadata types supported by the
uCDN may not match the set of GenericMetadata types supported by the
dCDN.
In the cases where a uCDN sends Metadata containing a GenericMetadata
type that a dCDN does not support, the dCDN MUST enforce the
semantics of the "mandatory-to-enforce" property. If a dCDN does not
understand or is unable to perform the functions associated with any
"mandatory-to-enforce" Metadata, the dCDN MUST NOT service any
requests for the corresponding content.
Note: Ideally, uCDNs would not delegate content requests to a dCDN
which does not support the "mandatory-to-enforce" Metadata associated
with the content being requested. However, even if the uCDN has a
priori knowledge of the Metadata supported by the dCDN (e.g., via the
CDNI capabilities interface or through out-of-band negotiation
between CDN operators) Metadata support may fluctuate or be
inconsistent (e.g., due to mis-communication, mis-configuration, or
temporary outage). Thus, the dCDN MUST always evaluate all Metadata
associated with content requests and reject any requests where
"mandatory-to-enforce" Metadata associated with the content cannot be
enforced.
6.7. Metadata Conflicts
It is possible that new Metadata definitions may obsolete or conflict
with existing property Metadata (e.g., a future revision of the CDNI
Metadata interface may redefine the Auth Metadata or a custom vendor
extension may implement an alternate Auth Metadata option). If
multiple Metadata (e.g., cdni.Auth.v2, vendor1.Auth, and
vendor2.Auth) all conflict with an existing Metadata (e.g.,
cdni.Auth) and all are marked as "mandatory-to-enforce", it may be
ambiguous which Metadata should be applied, especially if the
functionality of the Metadata overlap.
As described in Section 3.3, Metadata override only applies to
Metadata objects of the same exact type, found in HostMetadata and
nested PathMetadata structures. The CDNI Metadata interface does not
support enforcement of dependencies between different Metadata types.
It is the responsibility of the CSP and the CDN operators to ensure
that Metadata assigned to a given content do not conflict.
Note: Because Metadata is inherently ordered in GenericMetadata
lists, as well as in the PathMetadata hierarchy and PathMatch lists,
multiple conflicting Metadata types MAY be used, however, Metadata
hierarchies MUST ensure that independent PathMatch root objects are
used to prevent ambiguous or conflicting Metadata definitions.
6.8. Versioning
The version of CDNI Metadata Structural objects is conveyed inside
the MIME media type that is included in the HTTP Content-Type header.
Upon responding to a request for an object, a metadata server MUST
include a Content-Type header with the MIME media type containing the
version number of the object. HTTP requests sent to a metadata
server SHOULD include an Accept header with the MIME media type
(which includes the version) of the expected object. Metadata
clients can specify multiple MIME media types in the Accept header,
for example if a metadata client is capable of processing two
different versions of the same type of object (defined by different
MIME media types) it may decide to include both in the Accept header.
The version of each object defined by this document is version 1.
For example: "Content-Type: application/cdni.HostIndex.v1+json".
GenericMetadata objects include a "type" property which specifies the
MIME media type of the GenericMetadata value. This MIME media type
should also include a version. Any document which defines a new type
of GenericMetadata MUST specify the version number which it
describes. For example: "application/cdni.Location.v1+json".
7. IANA Considerations 7. IANA Considerations
This document requests the registration of the following MIME Media This document requests the registration of the following MIME Media
Type under the IANA MIME Media Type registry Type under the IANA MIME Media Type registry
(http://www.iana.org/assignments/media-types/index.html). (http://www.iana.org/assignments/media-types/index.html).
application/cdni.HostIndex.v1+json application/cdni.HostIndex.v1+json
application/cdni.HostMatch.v1+json application/cdni.HostMatch.v1+json
skipping to change at page 48, line 36 skipping to change at page 53, line 24
application/cdni.ProtocolRule.v1+json application/cdni.ProtocolRule.v1+json
application/cdni.DeliveryAuthorization.v1+json application/cdni.DeliveryAuthorization.v1+json
application/cdni.Cache.v1+json application/cdni.Cache.v1+json
application/cdni.Grouping.v1+json application/cdni.Grouping.v1+json
application/cdni.Auth.v1+json application/cdni.Auth.v1+json
application/cdni.CredentialsAuth.v1+json application/cdni.BasicAuth.v1+json
7.1. CDNI Metadata Footprint Types Registry 7.1. CDNI Metadata Footprint Types Registry
The IANA is requested to create a new "CDNI Metadata Footprint Types" The IANA is requested to create a new "CDNI Metadata Footprint Types"
registry. The "CDNI Metadata Footprint Types" namespace defines the registry. The "CDNI Metadata Footprint Types" namespace defines the
valid Footprint object type values used by the Footprint object in valid Footprint object type values used by the Footprint object in
Section 4.2.2.2. Additions to the Footprint type namespace conform Section 4.2.2.2. Additions to the Footprint type namespace conform
to the "Expert Review" policy as defined in [RFC5226]. The expert to the "Expert Review" policy as defined in [RFC5226]. The expert
reviewer should verify that new type definitions do not duplicate reviewer should verify that new type definitions do not duplicate
existing type definitions and prevent gratuitous additions to the existing type definitions and prevent gratuitous additions to the
skipping to change at page 49, line 31 skipping to change at page 54, line 22
[RFC5226]. The expert review should verify that new protocol [RFC5226]. The expert review should verify that new protocol
definitions do not duplicate existing protocol definitions and definitions do not duplicate existing protocol definitions and
prevent gratuitous additions to the namespace. prevent gratuitous additions to the namespace.
The following table defines the initial Protocol values: The following table defines the initial Protocol values:
+--------------+------------------------------------+---------------+ +--------------+------------------------------------+---------------+
| Protocol | Description | Specification | | Protocol | Description | Specification |
| Type | | | | Type | | |
+--------------+------------------------------------+---------------+ +--------------+------------------------------------+---------------+
| HTTP1.1 | Hypertext Transfer Protocol -- | RFC7230 | | http1.1 | Hypertext Transfer Protocol -- | RFC7230 |
| | HTTP/1.1 | | | | HTTP/1.1 | |
| HTTPS1.1 | HTTP/1.1 Over TLS | RFC2818 | | https1.1 | HTTP/1.1 Over TLS | RFC2818 |
+--------------+------------------------------------+---------------+ +--------------+------------------------------------+---------------+
7.3. CDNI Metadata Auth Types Registry 7.3. CDNI Metadata Auth Types Registry
The IANA is requested to create a new "CDNI Metadata Auth Types" The IANA is requested to create a new "CDNI Metadata Auth Types"
registry. The "CDNI Metadata Auth Type" namespace defines the valid registry. The "CDNI Metadata Auth Type" namespace defines the valid
Auth object types used by the Auth object in Section 4.3.6. Auth object types used by the Auth object in Section 4.2.7.
Additions to the Auth Type namespace conform to the "Expert Review" Additions to the Auth Type namespace conform to the "Expert Review"
policy as defined in [RFC5226]. The expert review should verify that policy as defined in [RFC5226]. The expert review should verify that
new type definitions do not duplicate existing type definitions and new type definitions do not duplicate existing type definitions and
prevent gratuitous additions to the namespace. prevent gratuitous additions to the namespace.
The following table defines the initial Auth type values: The following table defines the initial Auth type values:
+----------------+----------------------------------+---------------+ +-----------+---------------------------------------+---------------+
| Auth Type | Description | Specification | | Auth Type | Description | Specification |
+----------------+----------------------------------+---------------+ +-----------+---------------------------------------+---------------+
| CredentialAuth | Simple username and password | RFCthis | | httpbasic | Username and password authentication | RFCthis |
| | authentication. | | | | for use with HTTP Basic | |
+----------------+----------------------------------+---------------+ | | authentication. | |
+-----------+---------------------------------------+---------------+
8. Security Considerations 8. Security Considerations
8.1. Authentication 8.1. Authentication
Unauthorized access to metadata could result in denial of service. A Unauthorized access to metadata could result in denial of service. A
malicious metadata server, proxy server or an attacker performing a malicious metadata server, proxy server or an attacker performing a
"man in the middle" attack" could provide metadata to a dCDN that "man in the middle" attack could provide malicious metadata to a dCDN
denies service for one or more pieces of content to one or more user that either:
agents. A malicious metadata server (or an attacker performing a
"Man in the middle" attack") could modify metadata so that dCDNs are
directed to contact to malicious origin servers instead of the actual
origin servers. A malicious metadata client could continuously issue
large metadata requests to overload a uCDN's metadata server(s).
Unauthorized access to metadata could result in denial of service. A
malicious metadata server, proxy server or an attacker performing a
"man in the middle" attack could provide metadata to a dCDN that
either:
o Denies service for one or more pieces of content to one or more o Denies service for one or more pieces of content to one or more
User Agents; or User Agents; or
o Directs dCDNs to contact malicious origin servers instead of the o Directs dCDNs to contact malicious origin servers instead of the
actual origin servers. actual origin servers.
Unauthorized access to metadata could also enable a malicious Unauthorized access to metadata could also enable a malicious
metadata client to continuously issue large metadata requests in metadata client to continuously issue large metadata requests in
order to overload a uCDN's metadata server(s). order to overload a uCDN's metadata server(s).
Unauthorized access to metadata could result in leakage of private Unauthorized access to metadata could result in leakage of private
information. A malicious metadata client could request metadata in information. A malicious metadata client could request metadata in
order to gain access to origin servers, as well as information order to gain access to origin servers, as well as information
pertaining to content restrictions. pertaining to content restrictions.
An implementation of the CDNI Metadata interface SHOULD use mutual An implementation of the CDNI metadata interface SHOULD use mutual
authentication to prevent unauthorized access to metadata. authentication to prevent unauthorized access to metadata.
8.2. Confidentiality 8.2. Confidentiality
Unauthorized viewing of metadata could result in leakage of private Unauthorized viewing of metadata could result in leakage of private
information. A third party could intercept metadata transactions in information. A third party could intercept metadata transactions in
order to gain access to origin servers, as well as information order to gain access to origin servers, as well as information
pertaining to content restrictions. pertaining to content restrictions.
An implementation of the CDNI Metadata interface SHOULD use strong An implementation of the CDNI metadata interface SHOULD use strong
encryption to prevent unauthorized viewing of metadata. encryption to prevent unauthorized interception of metadata.
8.3. Integrity 8.3. Integrity
Unauthorized modification of metadata could result in denial of Unauthorized modification of metadata could result in denial of
service. A malicious metadata server, proxy server or an attacker service. A malicious metadata server, proxy server or an attacker
performing a "man in the middle" attack" could modify metadata performing a "man in the middle" attack" could modify metadata
destined to a dCDN in order to deny service for one or more pieces of destined to a dCDN in order to deny service for one or more pieces of
content to one or more user agents. A malicious metadata server, content to one or more user agents. A malicious metadata server,
proxy server or an attacker performing a "Man in the middle" attack" proxy server or an attacker performing a "Man in the middle" attack
could modify metadata so that dCDNs are directed to contact to could modify metadata so that dCDNs are directed to contact to
malicious origin servers instead of the actual origin servers. malicious origin servers instead of the actual origin servers.
An implementation of the CDNI Metadata interface SHOULD use strong An implementation of the CDNI metadata interface SHOULD use strong
encryption and mutual authentication to prevent unauthorized encryption and mutual authentication to prevent unauthorized
modification of metadata. modification of metadata.
8.4. Privacy 8.4. Privacy
Content provider origin and policy information is conveyed through Content provider origin and policy information is conveyed through
the CDNI Metadata interface. The distribution of this information to the CDNI metadata interface. The distribution of this information to
another CDN may introduce potential privacy concerns for some content another CDN may introduce potential privacy concerns for some content
providers, for example because dCDNs accepting content requests for a providers, for example because dCDNs accepting content requests for a
content provider's content may be able to obtain additional content provider's content may be able to obtain additional
information & usage patterns relating to the users of a content information & usage patterns relating to the users of a content
provider's services. Content providers with such concerns can provider's services. Content providers with such concerns can
instruct their CDN partners not to use CDN interconnects when instruct their CDN partners not to use CDN interconnects when
delivering that content provider's content. delivering that content provider's content.
8.5. Securing the CDNI Metadata interface 8.5. Securing the CDNI Metadata interface
An implementation of the CDNI Metadata interface MUST support TLS An implementation of the CDNI metadata interface MUST support TLS
transport as per [RFC2818] and [RFC7230]. The use of TLS for transport as per [RFC2818] and [RFC7230]. The use of TLS for
transport of the CDNI Metadata interface messages allows: transport of the CDNI metadata interface messages allows:
o The dCDN and uCDN to authenticate each other (to ensure they are o The dCDN and uCDN to authenticate each other.
transmitting/receiving CDNI Metadata requests & responses from an
authenticated CDN).
o CDNI Metadata interface requests and responses to be transmitted and, once they have mutually authenticated each other, it allows:
o The dCDN and uCDN to authorize each other (to ensure they are
transmitting/receiving CDNI metadata requests & responses from an
authorized CDN).
o CDNI metadata interface requests and responses to be transmitted
with confidentiality. with confidentiality.
o The integrity of the CDNI Metadata interface requests and o The integrity of the CDNI metadata interface requests and
responses to be protected during the exchange. responses to be protected during the exchange.
In an environment where any such protection is required, TLS MUST be In an environment where any such protection is required, TLS MUST be
used (including authentication of the remote end) by the server-side used (including authentication of the remote end) by the server-side
(uCDN) and the client-side (dCDN) of the CDNI Metadata interface (uCDN) and the client-side (dCDN) of the CDNI metadata interface
unless alternate methods are used for ensuring the confidentiality of unless alternate methods are used for ensuring the confidentiality of
the information in the CDNI Metadata interface requests and responses the information in the CDNI metadata interface requests and responses
(such as setting up an IPsec tunnel between the two CDNs or using a (such as setting up an IPsec tunnel between the two CDNs or using a
physically secured internal network between two CDNs that are owned physically secured internal network between two CDNs that are owned
by the same corporate entity). by the same corporate entity).
When TLS is used, the general TLS usage guidance in [RFC7525] MUST be When TLS is used, the general TLS usage guidance in [RFC7525] MUST be
followed. followed.
9. Acknowledgements 9. Acknowledgements
The authors would like to thank David Ferguson and Francois Le The authors would like to thank David Ferguson, Francois Le Faucheur,
Faucheur for their valuable comments and input to this document. Jan Seedorf and Matt Miller for their valuable comments and input to
this document.
10. Contributing Authors 10. Contributing Authors
[RFC Editor Note: Please move the contents of this section to the [RFC Editor Note: Please move the contents of this section to the
Authors' Addresses section prior to publication as an RFC.] Authors' Addresses section prior to publication as an RFC.]
Grant Watson Grant Watson
Velocix (Alcatel-Lucent) Velocix (Alcatel-Lucent)
3 Ely Road 3 Ely Road
Milton, Cambridge CB24 6AA Milton, Cambridge CB24 6AA
skipping to change at page 53, line 13 skipping to change at page 57, line 40
Email: kleung@cisco.com Email: kleung@cisco.com
11. References 11. References
11.1. Normative References 11.1. Normative References
[ISO3166-1] [ISO3166-1]
"https://www.iso.org/obp/ui/#search". "https://www.iso.org/obp/ui/#search".
[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, March 1997. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006. Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <http://www.rfc-editor.org/info/rfc4291>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
August 2008.
[RFC5861] Nottingham, M., "HTTP Cache-Control Extensions for Stale [RFC5861] Nottingham, M., "HTTP Cache-Control Extensions for Stale
Content", RFC 5861, May 2010. Content", RFC 5861, DOI 10.17487/RFC5861, May 2010,
<http://www.rfc-editor.org/info/rfc5861>.
[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 [RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
Address Text Representation", RFC 5952, August 2010. Address Text Representation", RFC 5952,
DOI 10.17487/RFC5952, August 2010,
<http://www.rfc-editor.org/info/rfc5952>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<http://www.rfc-editor.org/info/rfc7230>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer "Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, May 2015. (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <http://www.rfc-editor.org/info/rfc7525>.
11.2. Informative References 11.2. Informative References
[I-D.ietf-cdni-redirection] [I-D.ietf-cdni-redirection]
Niven-Jenkins, B. and R. Brandenburg, "Request Routing Niven-Jenkins, B. and R. Brandenburg, "Request Routing
Redirection Interface for CDN Interconnection", draft- Redirection Interface for CDN Interconnection", draft-
ietf-cdni-redirection-10 (work in progress), July 2015. ietf-cdni-redirection-11 (work in progress), July 2015.
[I-D.ietf-httpbis-http2]
Belshe, M., Peon, R., and M. Thomson, "Hypertext Transfer
Protocol version 2", draft-ietf-httpbis-http2-17 (work in
progress), February 2015.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000,
<http://www.rfc-editor.org/info/rfc2818>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC Resource Identifier (URI): Generic Syntax", STD 66,
3986, January 2005. RFC 3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content [RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
Distribution Network Interconnection (CDNI) Problem Distribution Network Interconnection (CDNI) Problem
Statement", RFC 6707, September 2012. Statement", RFC 6707, DOI 10.17487/RFC6707, September
2012, <http://www.rfc-editor.org/info/rfc6707>.
[RFC7230] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
(HTTP/1.1): Message Syntax and Routing", RFC 7230, June
2014.
[RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, [RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network "Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, August 2014. Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
August 2014, <http://www.rfc-editor.org/info/rfc7336>.
[RFC7337] Leung, K. and Y. Lee, "Content Distribution Network [RFC7337] Leung, K., Ed. and Y. Lee, Ed., "Content Distribution
Interconnection (CDNI) Requirements", RFC 7337, August Network Interconnection (CDNI) Requirements", RFC 7337,
2014. DOI 10.17487/RFC7337, August 2014,
<http://www.rfc-editor.org/info/rfc7337>.
[RFC7492] Bhatia, M., Zhang, D., and M. Jethanandani, "Analysis of [RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493,
Bidirectional Forwarding Detection (BFD) Security DOI 10.17487/RFC7493, March 2015,
According to the Keying and Authentication for Routing <http://www.rfc-editor.org/info/rfc7493>.
Protocols (KARP) Design Guidelines", RFC 7492, March 2015.
[XML-BASE] [RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Marsh, J., Ed. and R. Tobin, Ed., "XML Base (Second Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
Edition) - http://www.w3.org/TR/xmlbase/", January 2009. DOI 10.17487/RFC7540, May 2015,
<http://www.rfc-editor.org/info/rfc7540>.
Authors' Addresses Authors' Addresses
Ben Niven-Jenkins Ben Niven-Jenkins
Velocix (Alcatel-Lucent) Velocix (Alcatel-Lucent)
3 Ely Road 3 Ely Road
Milton, Cambridge CB24 6AA Milton, Cambridge CB24 6AA
UK UK
Email: ben@velocix.com Email: ben@velocix.com
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