Internet DRAFT - draft-ma-cdni-metadata
draft-ma-cdni-metadata
Network Working Group K. Ma
Internet-Draft Azuki Systems, Inc.
Intended status: Standards Track July 16, 2012
Expires: January 17, 2013
Content Distribution Network Interconnection (CDNI) Metadata Interface
draft-ma-cdni-metadata-03
Abstract
Content publishers (CPs) often use multiple Content Delivery Networks
(CDNs) to deliver content to consumers. Though existing interactions
between CPs and individual CDNs are beyond the scope of CDN
interconnection (CDNI), it is important to understand the management
capabilities and features available with existing non-interconnected
multi-CDN deployments. Before migrating to CDNI, CPs must first
assess the suitability of CDNI as a replacement for their existing
non-interconnected multi-CDN deployments. CDN feature configuration
and capability advertisement and enforcement is likely to occur
through the CDNI metadata interface (MI). This document describes an
approach to implementing the CDNI MI through the use of an extensible
metadata model and a light-weight HTTP-based API.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 17, 2013.
Copyright Notice
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Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 5
2. CDNI Metadata Data Model . . . . . . . . . . . . . . . . . . . 6
2.1. Domain Table . . . . . . . . . . . . . . . . . . . . . . . 7
2.2. Base Address Table . . . . . . . . . . . . . . . . . . . . 7
2.2.1. Hierarchical Base Addresses . . . . . . . . . . . . . 9
2.3. Agent Table . . . . . . . . . . . . . . . . . . . . . . . 9
2.4. Metadata Table . . . . . . . . . . . . . . . . . . . . . . 11
2.4.1. Hierarchical Metadata . . . . . . . . . . . . . . . . 12
3. CDNI Metadata Bootstrapping . . . . . . . . . . . . . . . . . 14
4. CDNI Metadata Management . . . . . . . . . . . . . . . . . . . 15
4.1. Metadata API . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.1. Metadata Creation . . . . . . . . . . . . . . . . . . 17
4.1.2. Metadata Update . . . . . . . . . . . . . . . . . . . 18
4.1.3. Metadata Refresh Trigger . . . . . . . . . . . . . . . 19
4.1.4. Metadata Retrieval . . . . . . . . . . . . . . . . . . 20
4.1.5. Metadata Removal . . . . . . . . . . . . . . . . . . . 22
4.1.6. Metadata Errors . . . . . . . . . . . . . . . . . . . 23
4.1.7. Metadata Prepositioning . . . . . . . . . . . . . . . 23
5. Metadata Definitions . . . . . . . . . . . . . . . . . . . . . 24
5.1. Origin Server . . . . . . . . . . . . . . . . . . . . . . 24
5.2. Activation Time . . . . . . . . . . . . . . . . . . . . . 24
5.3. Deactivation Time . . . . . . . . . . . . . . . . . . . . 25
5.4. Administrative Disable . . . . . . . . . . . . . . . . . . 25
5.5. Delegation Depth . . . . . . . . . . . . . . . . . . . . . 26
5.6. Footprint Filter . . . . . . . . . . . . . . . . . . . . . 26
5.7. HTTP Header Filter . . . . . . . . . . . . . . . . . . . . 27
5.8. HTTP Header Logging . . . . . . . . . . . . . . . . . . . 27
5.9. Protocol Filter . . . . . . . . . . . . . . . . . . . . . 27
5.10. SSL Required . . . . . . . . . . . . . . . . . . . . . . . 28
5.11. SSL Client Authentication Required . . . . . . . . . . . . 28
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5.12. URL Hash . . . . . . . . . . . . . . . . . . . . . . . . . 29
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
7. Security Considerations . . . . . . . . . . . . . . . . . . . 29
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 30
9. Appendix A: Domain API . . . . . . . . . . . . . . . . . . . . 30
9.1. Domain Creation . . . . . . . . . . . . . . . . . . . . . 31
9.2. Domain Update . . . . . . . . . . . . . . . . . . . . . . 31
9.3. Domain Retrieval . . . . . . . . . . . . . . . . . . . . . 31
9.4. Domain Removal . . . . . . . . . . . . . . . . . . . . . . 32
9.5. Domain Errors . . . . . . . . . . . . . . . . . . . . . . 32
10. Appendix B: Agent API . . . . . . . . . . . . . . . . . . . . 32
10.1. Agent Creation . . . . . . . . . . . . . . . . . . . . . . 33
10.2. Agent Update . . . . . . . . . . . . . . . . . . . . . . . 34
10.3. Agent Retrieval . . . . . . . . . . . . . . . . . . . . . 35
10.4. Agent Removal . . . . . . . . . . . . . . . . . . . . . . 35
10.5. Agent Errors . . . . . . . . . . . . . . . . . . . . . . . 35
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.1. Normative References . . . . . . . . . . . . . . . . . . . 36
11.2. Informative References . . . . . . . . . . . . . . . . . . 36
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 36
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1. Introduction
The use cases described in the CDNI use case document
[I-D.ietf-cdni-use-cases] provide motivational use cases for CDN
interconnection (CDNI). They describe reasons and situations where
CDNI provides a benefit to CDN vendors as well as content service
providers (CSPs). Additional use cases exist which describe how CDNs
are used today, however, these use cases often involve specific
features (e.g., customized content transformations, content security,
client authentication and filtering, content acquisition optimization
and redundancy, etc.) which are beyond the scope of CDNI. Though the
features themselves are not relevant to CDNI, the ability to support
those features or enforce policies related to those features in a
generic and extensible manner should be considered when designing
CDNI interfaces. The ability to support feature parity with existing
deployment models (i.e., non-CDNI-based CDN federation) may help to
remove barriers to CDNI adoption.
Though certain interfaces are out of scope of CDNI, e.g.:
o upstream CDN (uCDN) configuration by the CP
o uCDN content acquisition
o uCDN content delivery
o downstream CDN (dCDN) content acquisition
o end user (EU) content acquisition
o third party workflow management
o third party request routing
An awareness of these interfaces and an understanding of the
restrictions which they may impose on CDNI request routing is useful
for understanding the needs of the CDNI metadata interface (MI). As
described in the "Dynamic CDNI Metadata Acquisition Example" section
in the CDNI framework document [I-D.davie-cdni-framework], upon
receiving a request routing interface (RRI) request, the MI MAY be
used to retrieve metadata that is "considered" before responding to
the RRI request. To that end, the MI MUST define a deterministic
method for handling metadata processing. Though the definition and
interpretation of any individual piece of metadata is beyond the
scope of CDNI, a well-defined method for how to respond to a RRI
request when any unknown metadata value is encountered MUST be
supported.
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This document describes a simple data model for representing CDNI
metadata and a simple protocol for creating and retrieving CDNI
metadata in an opaque manner. The term opaque, in this case, should
be understood to mean: without understanding the underlying meaning
or interpretation of the metadata being represented. The metadata
model and retrieval protocol SHOULD be completely independent of the
definition of individual metadata values. The metadata model and
retrieval protocol MUST also define default behaviors for dealing
with metadata processing errors. The document defines a list of
metadata which are likely applicable to a broad range of CDNI
deployments. The document also provides a separate list of metadata
which are likely to be desirable to content publishers (CPs). This
document is not intended to suggest that any additional interfaces or
requirements are needed beyond those already specified in the CDNI
requirements document [I-D.ietf-cdni-requirements], nor is this
document intended to suggest that any out of scope interfaces or
content publisher feature functionality should be brought into scope.
The metadata examples provided are intended only to illustrate
possible features that interconnected CDNs may wish to support and
the extensibility of the metadata model to handle those situations.
1.1. Terminology
[Ed. insert terminology reference]
1.2. Abbreviations
o CDN: Content Distribution Network
o uCDN: Upstream Content Distribution Network
o dCDN: Downstream Content Distribution Network
o CDNI: Content Distribution Network Interconnection
o CP: Content Publisher
o CSP: Content Service Provider
o EU: End User
o NSP: Network Service Provider
o RRI: Request Routing Interface
o MI: Metadata Interface
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o CI: Control Interface
2. CDNI Metadata Data Model
The simple data model is shown in Figure 1 below. It includes a top
level Domain object which describes the site(s) to which metadata is
associated. The term site, in this case, should be understood to
mean a collection of related content assets accessed through a single
portal or Web-site. The Domain is associated with zero or more
opaque Metadata objects. Each Metadata object is associated with one
or more Base Address objects. The Metadata objects are each
associated with a URI extension, applicable to any of the associated
Base Addresses. A combination of Base Address and URI prefix
matching is used identify Metadata to allow for hierarchical
associations between individual Metadata and sets of content items.
Each Domain is also associated with one or more Agent objects.
Agents represent entities which require access to metadata (e.g.,
CPs, uCDNs, dCDNs, or local operators). An Agent is associated with
each Metadata entry allowing different Metadata values to be returned
to different Agents.
+----------+
| | 1
| Agent +---------------+
| | |
+----+-----+ |
| 1..* |
| |
| 1 | 0..*
+----+-----+ +----+-----+ +----------+
| | 1 0..* | | 1 1..* | |
| Domain +----------+ Metadata +----------+ BaseAddr |
| | | | | |
+----+-----+ +----------+ +----------+
Figure 1: CDNI Metadata Data Model
Note: The data model described above provides the basic components
required for distributing Metadata and implementing the CDNI MI. The
specific semantics of individual pieces of metadata are abstracted to
allow for opaque distribution of metadata. Not all of the
information described need be distributed through the MI. Some
information (e.g., Domains and Agents) may be necessary for the MI to
function, but MAY be negotiated or implemented out-of-band. They
could be configured either by the CDN as part of a non-CDNI process,
or through the CDNI control interface (CI) bootstrapping process, or
using the MI APIs described herein. The MI APIs may also be used by
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CDNs, internally, to configure themselves. The complete data model
and full set of APIs are provided as part of a holistic MI
description.
The following sections describe an example implementation of the
metadata scheme described above using a standard SQL database.
2.1. Domain Table
The Domain object contains basic information related to the site
being described. The example shown contains a primary key index and
a unique name for the site. An OPTIONAL site description (e.g., a
textual description of the site and its content) and site provider
(e.g., the name of the CP or CSP which owns the content) information
is also included.
CREATE TABLE "domain" ("domain_id" serial primary key,
"name" character varying(255) NOT NULL,
"provider" character varying(255),
"description" character varying(4095));
CREATE UNIQUE INDEX index_domain ON domain (name);
The Domain is the central object for binding Metadata. The example
Domain shown below highlights the descriptive nature of the Domain
object:
domain_id: 1
name: acme
provider: acme rocket-powered products, inc
description: fine purveyors of high quality anvils, rubber bands,
bird seed, and rocket-powered footwear.
2.2. Base Address Table
The Base Address object contains basic hostname and base URI
information related to the site being accessed. The example shown
requires a primary key index, a string containing the hostname and
base URI, and a foreign key reference to the Metadata to which this
Base Address is associated. A uniqueness constraint is imposed on
baseaddr/metadata_id pairs to prevent duplicate Base Address entries
for a given Metadata.
CREATE TABLE "baseaddr" ("baseaddr_id" serial primary key,
"baseaddr" character varying(255) NOT NULL,
"metadata_id" integer NOT NULL);
CREATE UNIQUE INDEX index_baseaddr ON baseaddr (baseaddr,
metadata_id);
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Base Address Table Definition
The Base Address objects allows multiple hostname and base URI pairs
to be associated with each Metadata object denoting the list of Base
Addresses through which content within the Domain may be accessed.
There are many cases where different Base Addresses are used to
access the same content, e.g.:
o internal vs. external addresses: content may be accessible via
both internal 10-net IP addresses and their associated DNS
addresses and base URIs, as well as publicly routable external IP
addresses and their associated DNS addresses and base URIs, where
all of the addresses point to the same content servers and the
base URIs are mapped to the same base directories,
o service white-labeling: multiple CSPs may provide access to the
same content through different branded services where each branded
service has its own DNS address and/or base URI, but all of the
services point to the same content, or
o analytics partitioning: redirects from other sites may use
different DNS addresses and/or base URIs, so that they may be
easily accounted for, while still pointing at the same content.
The example Base Addresses shown below represent two DNS addresses
through which content may be accessed as well as an internal IP
address which may be used for staging:
baseaddr_id: 1
baseaddr: wile.e.coyote.acme.com
metadata_id: 1
baseaddr_id: 2
baseaddr: road.runner.acme.com
metadata_id: 1
baseaddr_id: 3
baseaddr: 10.10.10.10/meemeep
metadata_id: 1
Note: The exact schema described above may result in heavy
duplication of Base Addresses. It is presented as an example for its
simplicity, however, it may be optimized by using other table joining
implementation schemes.
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2.2.1. Hierarchical Base Addresses
In order to support hierarchical Base Addresses, the wildcard '*.'
SHOULD be allowed as the first part of DNS-type Base Addresses. The
wildcard does not make sense at the beginning of IP Address-type Base
Addresses. Though a wildcard at the end of IP Address-type Base
Addresses would make more sense, support for IP Address-type Base
Addresses is OPTIONAL. The wildcard signifies the applicability of
the associated Metadata value to all Base Addresses which match the
address suffix.
The following two Base Addresses condense the previous example by
allowing all acme.com DNS addresses:
baseaddr_id: 1
baseaddr: *.acme.com
metadata_id: 1
baseaddr_id: 2
baseaddr: 10.10.10.10/meemeep
metadata_id: 1
Note: There is no explicit enforcement that Base Addresses associated
with a given piece of Metadata not overlap, however, for performance
reasons, Base Addresses associated with a given piece of Metadata
SHOULD NOT be allowed to overlap.
2.3. Agent Table
The Agent object contains basic information for authenticating
entities which require access to Metadata. The example shown
contains a primary key index, a string containing the username, an
OPTIONAL string containing the password (possibly hashed or
encrypted), a boolean value for differentiating between full read/
write access (e.g., for uCDNs) and read only access (e.g., for
dCDNs), and a foreign key reference to the Domain to which this Agent
is associated. A uniqueness constraint is imposed on username/
domain_id pairs to prevent duplicate Agent entries for a given
Domain.
CREATE TABLE "agent" ("agent_id" serial primary key,
"username" character varying(255) NOT NULL,
"password" character varying(255),
"read_only" boolean DEFAULT false NOT NULL,
"domain_id" integer NOT NULL);
CREATE UNIQUE INDEX index_agent ON agent (username, domain_id);
Agent Table Definition
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Note: The password field is included to support the HTTP
authentication described in the API sections, however, if alternate
authentication schemes are used, the password may not be necessary.
The Agent objects manage Metadata access rights. The Agent
functionality as described attempts to address two issues:
o security concerns: where unauthorized injection or deletion of
Metadata may alter the functionality of a content service and MUST
be prevented, as described in the Security Considerations section,
and
o customization requirements: where retrieval of certain metadata
may require different responses depending on the Agent who is
accessing the Metadata (e.g., with multiple and/or cascaded
dCDNs).
Note: Though both of the above issues could be addressed through
means outside of the MI, or through a means common to all of the CDNI
interfaces, the Agent serves the purpose of addressing these needs
within the context of the MI, in lieu of a consensus alternative and
as per the CDNI framework document [I-D.davie-cdni-framework].
The example Agents shown below represent a uCDN Agent with write
privileges and two dCDN Agents with read-only permissions:
agent_id: 1
username: ucdn
password: xxx
read_only: false
domain_id: 1
agent_id: 2
username: dcdn1
password: yyy
read_only: true
domain_id: 1
agent_id: 3
username: dcdn2
password: zzz
read_only: true
domain_id: 1
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2.4. Metadata Table
The Metadata object contains the actual individual pieces of metadata
for the site being described. The example shown contains a primary
key index, a string containing the URI(s) to which the metadata
applies, a name/value pair of strings which represent the name and
value of the Metadata, respectively, as well as a boolean value
stating whether or not the given Metadata must be enforced. An
OPTIONAL priority value is included for creating order lists of
values for a given named Metadata. An OPTIONAL ttl value and timeout
field are included to support metadata invalidation. The table also
contains a foreign key reference to the Domain to which this Metadata
is associated and a foreign key reference to the Agent to whom this
Metadata is intended. A compound uniqueness constraint is also
applied to each uri/name/priority/domain_id/agent_id tuple to prevent
a given Metadata from being ambiguously applied multiple times to the
same URI in a given Domain for a given Agent.
CREATE TABLE "metadata" ("metadata_id" serial primary key,
"uri" character varying(4095) NOT NULL,
"name" character varying(511) NOT NULL,
"value" character varying(65535) NOT NULL,
"must_enforce" boolean DEFAULT true NOT NULL,
"priority" integer DEFAULT 0 NOT NULL,
"ttl" integer DEFAULT 0 NOT NULL,
"timeout" timestamp without time zone,
"domain_id" integer NOT NULL,
"agent_id" integer NOT NULL);
CREATE UNIQUE INDEX index_metadata ON metadata (uri, name, priority,
domain_id, agent_id);
The name/value pair is represented as simple opaque strings. The MI
does not require and understanding of the semantics or inherent
meaning of Metadata names or values to distribute the Metadata.
Though, each piece of Metadata MUST have a defined set of semantics
in order to be enforced, distributing the Metadata and determining
whether or not the Metadata is supported does not require any
understanding of the Metadata semantics, but rather, only an ability
to identify supported Metadata by their name is REQUIRED. Metadata
names SHOULD be properly defined and registered, and any implied
functionality SHOULD be agreed upon and documented. A base set of
CDNI Metadata is provided in the Metadata Definitions Section.
The intent of the must_enforce boolean is to identify Metadata that
MUST be enforced by all CDNs. If a CDN is unable to understand or is
unable to comply with the Metadata, it MUST NOT deliver the content
being requested. For dCDNs, the must_enforce flag defines how to
respond to MI and RRI requests when unknown or unsupported Metadata
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is encountered. If Metadata is marked as must_enforce, then the dCDN
MUST NOT accept any RRI request if it is unable to enforce that piece
of Metadata (e.g., the named Metadata is not supported, the Metadata
value is invalid, or the Metadata value is not supported). If the MI
request resulted from a "recursive" RRI request, then the dCDN MUST
return an error to the uCDN. If the MI request resulted from an
"iterative" RRI request, then the dCDN MUST respond with a 403
Forbidden status code to the EU and report the failure to the uCDN.
In the case of cascaded CDN deployments, though a given CDN may not
be able to enforce a given piece of Metadata, other CDNs further down
stream may be able to enforce that Metadata. When a Metadata
rejection occurs, the CDN SHOULD still store the Metadata so that it
can be provided to other dCDNs.
The OPTIONAL priority value is provided to allow configuration of
ordered Metadata lists. When specifying multiple values for a given
named Metadata, each value MUST be specified with a unique priority
value. The explicit priority value enforces a deterministic ordering
across MI implementations.
The OPTIONAL ttl value is provided to allow configuration of a
Metadata TTLs. If the ttl is specified, it MUST be specified in
seconds and the timeout field SHOULD be populated by the local MI
processor and used internally, to prevent the need for clock
synchronization between MI processors.
The association of each Metadata to an Agent allows different Agents
to retrieve different Metadata values for a given URI in the given
Domain. This is intended to allow CDNs to separate upstream Metadata
from downstream Metadata (e.g., a uCDN content acquisition URL may
point to a CP origin, however, the content acquisition URL that the
dCDN retrieves from the uCDN may point at a surrogate in the uCDN;
likewise the content acquisition URLs for different dCDNs may point
at different surrogates in the uCDN). Though this information could
be hidden within a CDN's implementation, the security aspects related
to deterministically associating an authenticated Agent with the
proper metadata should be considered as part of the MI. Explicitly
representing this in the data model reduces ambiguity in Metadata
retrieval.
2.4.1. Hierarchical Metadata
In order to support hierarchical metadata, '/*' SHOULD be allowed as
the last part of the URI hierarchy, signifying the application of
this Metadata value to all URIs which match this URI prefix. If
multiple Metadata are defined with overlapping prefixes, the URI with
the longest prefix match MUST be used. The uniqueness constraint on
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the uri/name/priority/domain_id tuple allows for unambiguous
resolution of Metadata priority.
Note: The wildcard is only supported at the end of the URI string to
provide a well-defined ordering for URI prefixes (i.e., longest
prefix matching). Use of generalized regular expression matching
requires ordering rules to ensure deterministically coherent results
across multiple MI implementations. It is assumed that the URI path
extensions (beyond the base paths provided in the Base Address) for
content will be the same across CDNs. Any CDN specific URL rewrites
MUST only affect the Base Address portion of the URL as defined in
the Base Address.
Note: It is often desirable to separate specific types of files which
may live in the same directory (e.g., .m3u8 vs .ts). Wildcard
support in the URI support for file extension differentiation, i.e.,
'/*[.extension]', is OPTIONAL.
Given the following four Metadata objects, the value of color is
defined five times, for three different URIs, all within the same
Domain, but for different Agents:
metadata_id: 1
uri: /*
name: color
value: blue
must_enforce: false
priority: 0
ttl: 0
domain_id: 1
agent_id: 2
metadata_id: 2
uri: /*
name: color
value: gold
must_enforce: false
priority: 0
ttl: 0
domain_id: 1
agent_id: 1
metadata_id: 3
uri: /*
name: color
value: blue
must_enforce: false
priority: 1
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ttl: 0
domain_id: 1
agent_id: 1
metadata_id: 4
uri: /grass/*
name: color
value: brown
must_enforce: false
priority: 0
ttl: 0
domain_id: 1
agent_id: 2
metadata_id: 5
uri: /grass/on/the/other/side/*
name: color
value: green
must_enforce: false
priority: 0
ttl: 0
domain_id: 1
agent_id: 2
The default value for the color metadata (signified by the all
encompassing URI "/*") is blue for the dCDN Agent and gold for the
uCDN Agent, though the default color may be blue for the uCDN as well
(as signified by the lower priority alternate color value).
Alternate colors are associated with requests from the dCDN Agent for
URIs that begin with "/grass". By default "/grass" has a color of
brown, except when requesting "/grass/on/the/other/side/" which is
green.
3. CDNI Metadata Bootstrapping
It is assumed that a well-known hostname to which MI requests should
be sent is configured through the CDNI bootstrap data. Bootstrap
information is sent through the CDNI CI, as described in the CDNI
requirements document [I-D.ietf-cdni-requirements]. The MI APIs
described herein are intended to be serviced by the MI running on
that host.
Domain and Agent configurations must exist prior to Metadata
creation/retrieval. Domains and Agents MAY be created as a part of
an off-line business negotiation process or as a part of the CDNI
bootstrapping process. Domain and Agent API descriptions are
included in Appendix A and Appendix B, respectively. When the Domain
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and Agent APIs described are used, access to the APIs SHOULD be
secured using SSL with client authentication as described in the
Security Considerations section.
Two sets of Agent configurations are also REQUIRED:
o Upstream Agent Configuration: Agent credentials for all external
agents who require access to the local CDN MI, e.g. for dCDNs to
retrieve Metadata or for uCDNs to trigger Metadata.
o Downstream Agent Configuration: Agent credentials for the local
CDN to use when accessing uCDN MIs for retrieving Metadata or
triggering Metadata responses. Separate credentials may be
required for each uCDN and Domain combination from which content
redirections may originate.
4. CDNI Metadata Management
The Metadata creation, modification, retrieval and removal protocols
are defined in the following sections. All use a simple HTTP-based
approach. The protocol, in general, SHOULD be data format agnostic.
The examples shown herein use an XML representation for MI requests/
responses, however, other well-defined representations (e.g., JSON)
are also acceptable. The examples shown illustrate functionality
required to support the data model described in Section 2, however,
any protocol which allows for the forced retrieval, invalidation, and
removal of Metadata could also be acceptable.
Metadata creation/update is distinguished from retrieval by the HTTP
method. Metadata creation/update MUST use the POST method. Metadata
retrieval MUST use the GET method. Metadata MUST be removed if the
value field is empty (i.e., updating the value to be an empty string
MUST force removal of the entire Metadata entry and all associated
Base Address entries).
A trigger API is also specified to initiate retrieval of Metadata.
The uCDN may issue a trigger to the dCDN to force (re)acquisition of
Metadata by the dCDN. The trigger API MUST use the POST method.
In addition to being secured using SSL with client authentication as
described in the Security Considerations section, the MI SHOULD also
employ an additional Agent authentication mechanism to filter
requests and results. In the examples shown below, HTTP basic
authentication is used for Agent authentication, though other methods
(e.g., HTTP digest authentication or URL hashing) could also be used.
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4.1. Metadata API
The Metadata for a Domain is created/modified/retrieved using the
"/CDNI/MI/metadata" API. The metadata API REQUIRES a single query
string argument "domain" which specifies the name of the Domain to
which the Metadata being created/modified/retrieved belongs. Three
additional OPTIONAL arguments MAY also be provided when retrieving
metadata: "name" which specifies the name of the Metadata field to
create/modify/retrieve, "uri" which specifies the URI for which the
Metadata must apply, and/or "agent" which specifies the agent(s) to
which the Metadata is associated, as a comma separated list. The
"agent" option MUST only be allowed for agents with full read/write
permissions.
A simple XML representation of the information provided to the
metadata creation/update API or returned from the metadata retrieval
API is shown below:
<metadatas>
<metadata>
<uri></uri>
<name></name>
<values>
<set>
<value></value>
<priority></priority>
</set>
...
</values>
<must_enforce></must_enforce>
<ttl></ttl>
<agent></agent>
<baseaddrs>
<baseaddr></baseaddr>
...
</baseaddrs>
</metadata>
...
</metadatas>
Metadata retrieval for a Domain may be triggered using the "/CDNI/MI/
trigger" API. The trigger API provides the information required to
issue a metadata API retrieval request (i.e., the "domain", "name,
and "uri" query string arguments). The metadata API REQUIRES a
single query string argument "action" which specifies what type of
action is being triggered.
The following actions MUST be supported:
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o refresh: The dCDN MUST retrieve and update all Metadata specified
in the trigger.
The following actions are considered OPTIONAL:
o preposition: The dCDN SHOULD retrieve and update all Metadata
specified in the trigger.
A simple XML representation of the information provided to the
trigger API is shown below:
<triggers>
<trigger>
<host></host>
<domain></domain>
<name></name>
<uri></uri>
</trigger>
...
</triggers>
4.1.1. Metadata Creation
The following example creates three new Metadata "color" for the
"dcdn" Agent in the "acme" Domain, issued by the "ucdn" Agent to the
uCDN MI:
POST /CDNI/MI/metadata?domain=acme HTTP/1.1
Host: ucdn.mi.cdni.example.com
Accept: */*
Authorization: Basic dWNkbjp4eHg=
Content-Length: 1053
Content-Type: application/x-www-form-urlencoded
<metadatas>
<metadata>
<uri>/grass/*</uri>
<name>color</name>
<values>
<set>
<value>brown</value>
<priority>0</priority>
</set>
</values>
<must_enforce>false</must_enforce>
<ttl></ttl>
<agent>dcdn</agent>
<baseaddrs>
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<baseaddr>*.acme.com</baseaddr>
</baseaddrs>
</metadata>
<metadata>
<uri>/grass/on/the/other/side/*</uri>
<name>color</name>
<values>
<set>
<value>green</value>
<priority>0</priority>
</set>
</values>
<must_enforce>true</must_enforce>
<ttl></ttl>
<agent>dcdn</agent>
<baseaddrs>
<baseaddr>*.acme.com</baseaddr>
</baseaddrs>
</metadata>
<metadata>
<uri>/glasses/*</uri>
<name>color</name>
<values>
<set>
<value>violet</value>
<priority>0</priority>
</set>
</values>
<must_enforce>false</must_enforce>
<ttl></ttl>
<agent>ucdn</agent>
<baseaddrs>
<baseaddr>*.acme.com</baseaddr>
</baseaddrs>
</metadata>
</metadatas>
4.1.2. Metadata Update
The following example updates the "color" Metadata for the
"/glasses/*" portion of the "acme" Domain and "dcdn" Agent, issued by
the "ucdn" Agent to the uCDN MI:
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POST /CDNI/MI/metadata?domain=acme HTTP/1.1
Host: ucdn.mi.cdni.example.com
Accept: */*
Authorization: Basic dWNkbjp4eHg=
Content-Length: 361
Content-Type: application/x-www-form-urlencoded
<metadatas>
<metadata>
<uri>/glasses/*</uri>
<name>color</name>
<values>
<set>
<value>rose</value>
<priority>0</priority>
</set>
<set>
<value>violet</value>
<priority>2</priority>
</set>
</values>
<must_enforce>true</must_enforce>
<ttl></ttl>
<agent>ucdn</agent>
<baseaddrs>
<baseaddr>*.acme.com</baseaddr>
</baseaddrs>
</metadata>
</metadatas>
4.1.3. Metadata Refresh Trigger
The following example triggers the refresh of all "color" Metadata
for the "acme" Domain. The trigger is issued by the "ucdn" Agent to
the dCDN MI and is intended to force the "dcdn" Agent to retrieve
Metadata from the uCDN MI.
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POST /CDNI/MI/trigger?action=refresh HTTP/1.1
Host: dcdn.mi.cdni.example.com
Accept: */*
Authorization: Basic dWNkbjp4eHg=
Content-Length: 155
Content-Type: application/x-www-form-urlencoded
<triggers>
<trigger>
<host>ucdn.mi.cdni.example.com</host>
<domain>acme</domain>
<name>color</name>
<uri></uri>
</trigger>
</triggers>
The following example triggers the refresh of all Metadata for the
URI "/grass/on/this/side", in the "acme" Domain. The trigger is
issued by the "ucdn" Agent to the dCDN MI and is intended to force
the "dcdn" Agent to retrieve Metadata from the uCDN MI.
POST /CDNI/MI/trigger?action=refresh HTTP/1.1
Host: dcdn.mi.cdni.example.com
Accept: */*
Authorization: Basic dWNkbjp4eHg=
Content-Length: 169
Content-Type: application/x-www-form-urlencoded
<triggers>
<trigger>
<host>ucdn.mi.cdni.example.com</host>
<domain>acme</domain>
<name></name>
<uri>/grass/on/this/side</uri>
</trigger>
</triggers>
4.1.4. Metadata Retrieval
The following example retrieves all "color" Metadata for the "acme"
Domain. The request was issued by the "dcdn" Agent to the uCDN MI,
and the results are filtered for the "dcdn" Agent:
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GET /CDNI/MI/metadata?domain=acme&name=color HTTP/1.1
Host: ucdn.mi.cdni.example.com
Accept: */*
Authorization: Basic ZGNkbjp5eXk=
HTTP/1.1 200 OK
Content-Length: 714
Connection: close
Content-Type: text/xml
<metadatas>
<metadata>
<uri>/grass/*</uri>
<name>color</name>
<values>
<set>
<value>brown</value>
<priority>0</priority>
</set>
</values>
<must_enforce>false</must_enforce>
<ttl></ttl>
<agent>dcdn</agent>
<baseaddrs>
<baseaddr>*.acme.com</baseaddr>
</baseaddrs>
</metadata>
<metadata>
<uri>/grass/on/the/other/side/*</uri>
<name>color</name>
<values>
<set>
<value>green</value>
<priority>0</priority>
</set>
</values>
<must_enforce>true</must_enforce>
<ttl></ttl>
<agent>dcdn</agent>
<baseaddrs>
<baseaddr>*.acme.com</baseaddr>
</baseaddrs>
</metadata>
</metadatas>
The following example retrieves the Metadata for the URI "/grass/on/
this/side" in the "acme" Domain. The request was issued by and the
results are filtered for the "dcdn" Agent:
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GET /CDNI/MI/metadata?domain=acme&uri=/grass/on/this/side HTTP/1.1
Host: ucdn.mi.cdni.example.com
Accept: */*
Authorization: Basic ZGNkbjp5eXk=
HTTP/1.1 200 OK
Content-Length: 361
Connection: close
Content-Type: text/xml
<metadatas>
<metadata>
<uri>/grass/*</uri>
<name>color</name>
<values>
<set>
<value>brown</value>
<priority>0</priority>
</set>
</values>
<must_enforce>false</must_enforce>
<ttl></ttl>
<agent>dcdn</agent>
<baseaddrs>
<baseaddr>*.acme.com</baseaddr>
</baseaddrs>
</metadata>
</metadatas>
4.1.5. Metadata Removal
The following example removes the violet "color" Metadata value for
the URI "/glasses/*" and the "ucdn" Agent in the "acme" Domain by
setting the value to an empty string, issued by the "ucdn" Agent to
the uCDN MI:
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POST /CDNI/MI/metadata?domain=acme HTTP/1.1
Host: ucdn.mi.cdni.example.com
Accept: */*
Authorization: Basic dWNkbjp4eHg=
Content-Length: 225
Content-Type: application/x-www-form-urlencoded
<metadatas>
<metadata>
<uri>/glasses/*</uri>
<name>color</name>
<values>
<set>
<value/>
<priority>2</priority>
</set>
</values>
<agent>ucdn</agent>
</metadata>
</metadatas>
4.1.6. Metadata Errors
For any update, retrieval, or trigger request with malformed XML, the
MI SHOULD respond with a 400 Bad Request status code. Ancillary
unknown tags MAY be ignored.
For any trigger requests with an unsupported action, the MI SHOULD
respond with a 403 Forbidden status code.
For any update or retrieval request for a uri/name/domain_id tuple
which does not exist, the MI SHOULD respond with a 404 Not Found
status code.
For any request which lacks a valid Agent authorization, the MI MUST
respond with a 401 Unauthorized status code. This includes Agents
with valid credentials, but who are marked as read_only and have
requested Metadata associated with an alternate Agent through the
specification of an "agent" query string parameter.
For any request which results in Metadata with an expired TTL, and
for which an update cannot be retrieved from an upstream MI, the MI
MUST respond to with a 500 Internal Server status code.
4.1.7. Metadata Prepositioning
The metadata creation/modification/removal APIs discussed above
SHOULD only be used by uCDNs to manage Metadata in the local CDN.
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Though the metadata creation/modification/removal APIs could be used
to preposition metadata in dCDNs, the trigger API allows the uCDN to
force refresh of the dCDN Metadata without directly posting Metadata
to the dCDN. This allows the dCDNs to manage retrieval of Metadata
using lazy updates.
dCDNs SHOULD NOT modify metadata dictated by a uCDN. dCDNs SHOULD
only be assigned Agents with read_only access and SHOULD NOT have
access to uCDN Domain or Agent APIs (restricted through the use of
different SSL client authentication certificates, as described in the
Security Considerations section).
5. Metadata Definitions
This section defines a base set of Metadata which SHOULD be supported
by all CDNI implementations.
5.1. Origin Server
Content which is not pre-positioned must be acquired by the CDN from
an origin server. The origin server Metadata specifies the base URL
to which the content request URI may be appended in order to acquire
the content. The origin server Metadata is defined as having the
name "origin_server", with valid values containing a comma separated
list of base URLs, and the must_enforce flag set to false:
name: origin_server
value: <url>
must_enforce: false
In some cases, multiple non-load balanced origin servers may be
available for content acquisition. The origin server Metadata SHOULD
support an unprioritized comma separate list of base URL values.
Note: The origin list Metadata is not a must_enforce, since, if the
content cannot be acquired, there is no threat of unauthorized
content distribution. Other Metadata or content pre-positioning may
negate the need for origin server Metadata.
5.2. Activation Time
Content may be pre-positioned in anticipation of demand, however, the
content license may have restrictions on delivery timeframe. The
activation time Metadata specifies the first time at which the
content may be delivered. The activation time Metadata is defined as
having the name "activation_time", with valid timestamp values that
MUST conform to RFC3339 [RFC3339], and the must_enforce flag set to
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true:
name: activation_time
value: <timestamp>
must_enforce: true
If the activation time Metadata is set and the current time is less
than the specified activation time, the CDN MUST respond to requests
for that content with a 403 Forbidden status code (or equivalent for
the given non-HTTP request protocol).
5.3. Deactivation Time
Content may be pre-positioned in anticipation of demand, however, the
content license may have restrictions on delivery timeframe. The
deactivation time Metadata specifies the last time at which the
content may be delivered. The deactivation time Metadata is defined
as having the name "deactivation_time", with valid timestamp values
that MUST conform to RFC3339 [RFC3339], and the must_enforce flag set
to true:
name: deactivation_time
value: <timestamp>
must_enforce: true
If the deactivation time Metadata is set and the current time is
greater than the specified activation time, the CDN MUST respond to
requests for that content with a 403 Forbidden status code (or
equivalent for the given non-HTTP request protocol).
5.4. Administrative Disable
It is sometimes necessary to temporarily disable the distribution of
certain media (e.g., inappropriate content, irregular access
patterns, etc.) within a set accessibility period (i.e., the
activation/deactivation time range). The administrative disable
Metadata instructs the CDN not to deliver the specified content under
any circumstances. The administrative disable Metadata is defined as
having the name "admin_disable", with two valid values "true" and
"false", and the must_enforce flag set to true:
name: admin_disable
value: [true | false]
must_enforce: true
If the administrative disable Metadata is set to "true", the CDN MUST
respond to requests for that content with a 403 Forbidden status code
(or equivalent for the given non-HTTP request protocol).
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5.5. Delegation Depth
CSPs may wish to prevent cascading CDNs to enforce licensing
restrictions. The delegation depth Metadata instructs the CDN to
only delegate requests for the specified content if the delegation
depth is greater than zero. If the depth is less than or equal to
zero, a uCDN should not delegate requests for the specified content
to any dCDNs under any circumstances. When distributing the
delegation depth Metadata the uCDN MUST decrement the value of
delegation depth by at least one if the current value is greater than
zero. The uCDN MAY choose not to decrement the value if the value is
already less than or equal to zero. The uCDN MAY decrement by more
than one in order to get to zero. The delegation depth Metadata is
defined as having the name "delegate_depth", with an integer value
and the must_enforce flag set to true:
name: delegate_depth
value: <integer>
must_enforce: true
If the delegation depth Metadata is less than or equal to 0, the CDN
MUST either service the content requests itself or respond to
requests for that content with a 504 Server Busy status code (or
equivalent for the given non-HTTP request protocol).
5.6. Footprint Filter
CSPs often purchase rights to content which are only valid when
accessed from certain locations (e.g., within a given country or
through a given access network). The footprint filter Metadata
provides a list of valid source IP subnets from which content
requests may be accepted. The footprint filter Metadata is defined
as having the name "footprint", with valid values containing a comma
separated list of IP subnet definitions, and the must_enforce flag
set to true:
name: footprint
value: <ip_subnet> [, <ip_subnet>]...
must_enforce: true
If the footprint filter Metadata is set and the source address of a
requesting client does not match any of the IP subnets listed, the
CDN MUST respond to the content request with a 403 Forbidden status
code (or equivalent for the given non-HTTP request protocol).
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5.7. HTTP Header Filter
CSPs often desire the ability to filter requests based on the
existence of specific HTTP header fields and values (e.g., User-Agent
headers for device detection or custom headers inserted by client-
side applications). The HTTP header filter Metadata provides a list
of HTTP header names and values which MUST be verified. The HTTP
header filter Metadata is defined as having the name
"http_filter_headers", with valid values containing a comma separated
list of HTTP header names and regular expression matching criteria
definitions, and the must_enforce flag set to true:
name: http_filter_headers
value: <name>:<regex> [, <name>:<regex>]...
must_enforce: true
If the HTTP header filter Metadata is set and the HTTP headers of the
content request do not match all of the filters specified, the CDN
MUST respond to the content request with a 403 Forbidden status code
(or equivalent for the given non-HTTP request protocol).
5.8. HTTP Header Logging
CSP client applications often include proprietary headers in their
content requests (e.g., for user tracking or analaytics collection)
which may be needed for business reasons (e.g., billing) or may be
useful for debugging purposes. The HTTP header logging Metadata
provides a list of HTTP header names whose values MUST be extracted
and logged with the normal per-request information passed through the
CDNI logging interface. The HTTP header logging Metadata is defined
as having the name "http_logging_headers", with valid values
containing a comma separated list of HTTP header names, and the
must_enforce flag flag optionally set to true (depending on the
application):
name: http_logging_headers
value: <name> [, <name>]...
must_enforce: [true | false]
If the HTTP header logging Metadata is set and the content request
contains HTTP headers which match any of the header names listed, the
CDN MUST extract all matching headers and add them to the per-request
log message.
5.9. Protocol Filter
Though content is typically only accessible using specific a protocol
(e.g., HTTP, RTMP, or RTSP), a CSP may wish to explicitly allow/
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disallow access to certain content for a given protocol. The
protocol filter Metadata provides a list of allowed protocols via
which content may be delivered. The protocol filter Metadata is
defined as having the name "protocol", with valid values containing a
comma separate list of protocol strings, and the must_enforce flag
set to true:
name: protocols
value: <protocol> [, <protocol>]...
must_enforce: true
If the protocol filter Metadata is set and the request protocol does
not match any protocol in the list, the CDN MUST respond to the
content request with a 403 Forbidden status code (or equivalent for
the given non-HTTP request protocol).
5.10. SSL Required
CSPs which require delivery privacy may require dCDNs to support the
same SSL configurations which were applied to the uCDN. The SSL
required Metadata expresses the requirement to enforce SSL on content
request connections and provides the necessary key and certificate
information required for server authentication. The SSL required
Metadata is defined as having the name "ssl_required", with valid
values containing two URLs (comma separated) which point to the key
and certificate, respectively, and the must_enforce flag set to true:
name: ssl_required
value: <key_url>,<cert_url>
must_enforce: true
If the SSL required Metadata is set and the request is not received
over an SSL channel, the CDN MUST respond to the content request with
a 403 Forbidden status code (or equivalent for the given non-HTTP
request protocol).
Note: Retrieval of server key and certificate information SHOULD be
performed in a secure manner. Retrieval could be implemented through
the CDNI MI, however, this is not required.
5.11. SSL Client Authentication Required
CSPs which require client authentication may require dCDNs to support
a SSL client authentication configuration which was applied to the
uCDN. The SSL client authentication required Metadata expresses the
requirement to enforce SSL client authentication on content requests
and provides the necessary certificate authority (CA) information for
authenticating clients. The SSL client authentication required
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Metadata is defined as having the name "ssl_auth_required", with
valid values containing a single URL which points to the CA
certificate to be used in client verification, and the must_enforce
flag set to true:
name: ssl_auth_required
value: <ca_url>
must_enforce: true
If the SSL client authentication required Metadata is set and the
client certificate cannot be verified using the CA certificate, the
CDN MUST respond with a handshake_failure alert.
5.12. URL Hash
TBD.
[Ed. Note: There are many proprietary URL hashing techniques in use
today with varying timestamp formats, query string parameter names,
hashing algorithm combinations, etc. A generic definition of URL
hashing algorithm parameters, capable of supporting all algorithms
would be best. An alternative of defining specific algorithms and
assigning each and enumerated identifier would also work.]
6. IANA Considerations
This memo includes no request to IANA.
7. Security Considerations
There are a number of security concerns associated with the MI as
Metadata may be used to influence CDNI request routing. Metadata may
describe content acquisition parameters or content security
restrictions. Altering Metadata or inhibiting Metadata discovery may
impact content distribution. Some MI concerns include:
o intercepting and discarding Metadata requests to prevent content
acquisition may be used as a denial of service attack,
o altering content acquisition Metadata to prevent content
acquisition may be used as a denial of service attack, and
o spoofing content security Metadata to disable delivery
restrictions may be used to circumvent rights management.
To combat these concerns, unauthorized access to the MI MUST be
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prevented. The use of SSL with client authentication SHOULD be used
for all MI APIs. Deployments in controlled environments where
physical security and IP address white-listing is employed MAY choose
not to use SSL. Different client authentication certificates SHOULD
be used to protect access to Domain and Agent APIs, as well as uCDN
access to the Metadata API, differently from dCDN access to the
Metadata API. Deployments where uCDNs and dCDNs are mutually trusted
entities (e.g., when uCDNs and dCDNs are controlled by the same
corporate organization) MAY choose to use a single client
authentication certificate.
8. Acknowledgements
The authors would like to thank Daniel Biagini, Susan He, Francois Le
Faucheur, Kent Leung, Ben Niven-Jenkins, Gilles Bertrand, and Raj
Nair for their helpful reviews and comments.
9. Appendix A: Domain API
Domain creation, modification, retrieval, and removal protocols are
defined in the following sections. All use a simple HTTP-based
approach. The protocol, in general, SHOULD be data format agnostic.
The examples shown herein use an XML representation for MI requests/
responses, however, other well-defined representations (e.g., JSON)
are also acceptable. The examples shown illustrate the functionality
required to support the data model described in Section 2, however,
any protocol which allows for the creation, modification, retrieval,
and removal of Domains could also be acceptable.
Domain creation/update is distinguished from domain retrieval and
removal by the HTTP method. Domain creation/update MUST use the POST
method. Domain retrieval MUST use the GET method. Domain removal
MUST use the DELETE method.
All Agents and Metadata MUST be associated with a Domain. A Domain
is created/modified/retrieved/removed using the "/CDNI/MI/domain"
API. The domain API REQUIRES a single query string argument "domain"
which specifies the name of the Domain to be created/modified/
retrieved.
A simple XML representation of the information provided to the domain
creation/update API or returned from the domain retrieval API is
shown below:
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<domain>
<provider></provider>
<description></description>
</domain>
9.1. Domain Creation
The following example creates a new Domain "acme":
POST /CDNI/MI/domain?domain=acme HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
Content-Length: 81
Content-Type: application/x-www-form-urlencoded
<domain>
<provider>acme</provider>
<description>acme</description>
</domain>
9.2. Domain Update
The following example updates the "acme" Domain:
POST /CDNI/MI/domain?domain=acme HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
Content-Length: 209
Content-Type: application/x-www-form-urlencoded
<domain>
<provider>acme rocket-powered products, inc</provider>
<description>fine purveyors of high quality anvils, rubber bands,
bird seed, and rocket-powered footwear.</description>
</domain>
9.3. Domain Retrieval
The following example retrieves the updated "acme" Domain
information:
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GET /CDNI/MI/domain?domain=acme HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
HTTP/1.1 200 OK
Content-Length: 209
Connection: close
Content-Type: text/xml
<domain>
<provider>acme rocket-powered products, inc</provider>
<description>fine purveyors of high quality anvils, rubber bands,
bird seed, and rocket powered footwear</description>
</domain>
The MI MAY support bulk retrieval of Domains through the use of a
comma separated list of Domain names in the domain query string
parameter.
9.4. Domain Removal
The following example removes the "acme" Domain:
DELETE /CDNI/MI/domain?domain=acme HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
9.5. Domain Errors
Any update or retrieval request with malformed XML SHOULD respond
with a 400 Bad Request status code. Ancillary unknown tags MAY be
ignored.
Any update or retrieval request for a Domain which does not exist
SHOULD respond with a 404 Not Found status code.
10. Appendix B: Agent API
Agent creation, modification, retrieval, and removal protocols are
defined in the following sections. All use a simple HTTP-based
approach. The protocol, in general, SHOULD be data format agnostic.
The examples shown herein use an XML representation for MI requests/
responses, however, other well-defined representations (e.g., JSON)
are also acceptable. The examples shown illustrate the functionality
required to support the data model described in Section 2, however,
any protocol which allows for the creation, modification, retrieval,
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and removal of Agents could also be acceptable.
Agent creation/update is distinguished from Agent retrieval and
removal by the HTTP method. Agent creation/update MUST use the POST
method. Agent retrieval MUST use the GET method. Agent removal MUST
use the DELETE method and specify the Agent name(s) in the query
string.
All Metadata MUST be associated with an Agent. An Agent is created/
modified/retrieved/removed using the "/CDNI/MI/agent" API. The agent
API REQUIRES a single query string argument "domain" which specifies
the name of the Domain to which the Agent has access. In the case of
DELETEs, the agent API also REQUIRES a query string argument "agent"
which specifies the name(s) of the Agent(s) to remove, as a comma
separated list.
A simple XML representation of the information provided to the agent
creation/update API or returned from the agent retrieval API is shown
below:
<agents>
<agent>
<username></username>
<password></password>
<read_only></read_only>
</agent>
...
</agents>
10.1. Agent Creation
The following example creates three new Agents "ucdn", "dcdn1", and
"dcdn2" for the "acme" Domain:
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POST /CDNI/MI/agent?domain=acme HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
Content-Length: 362
Content-Type: application/x-www-form-urlencoded
<agents>
<agent>
<username>ucdn</username>
<password>xxx</password>
<read_only>false</read_only>
</agent>
<agent>
<username>dcdn1</username>
<password>aaa</password>
<read_only>false</read_only>
</agent>
<agent>
<username>dcdn2</username>
<password>bbb</password>
<read_only>false</read_only>
</agent>
</agents>
10.2. Agent Update
The following example updates the "dcdn1" and "dcdn2" Agents in the
"acme" Domain:
POST /CDNI/MI/agent?domain=acme HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
Content-Length: 245
Content-Type: application/x-www-form-urlencoded
<agents>
<agent>
<username>dcdn1</username>
<password>yyy</password>
<read_only>true</read_only>
</agent>
<agent>
<username>dcdn2</username>
<password>zzz</password>
<read_only>true</read_only>
</agent>
</agents>
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10.3. Agent Retrieval
The following example retrieves the updated Agent information for the
"acme" Domain:
GET /CDNI/MI/agent?domain=acme HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
HTTP/1.1 200 OK
Content-Length: 360
Connection: close
Content-Type: text/xml
<agents>
<agent>
<username>ucdn</username>
<password>xxx</password>
<read_only>false</read_only>
</agent>
<agent>
<username>dcdn1</username>
<password>yyy</password>
<read_only>true</read_only>
</agent>
<agent>
<username>dcdn2</username>
<password>zzz</password>
<read_only>true</read_only>
</agent>
</agents>
10.4. Agent Removal
The following example removes the "dcdn1" Agent from the "acme"
Domain:
DELETE /CDNI/MI/agent?domain=acme&agent=dcdn1 HTTP/1.1
Host: host.mi.cdni.example.com
Accept: */*
10.5. Agent Errors
Any update or retrieval request with malformed XML SHOULD respond
with a 400 Bad Request status code. Ancillary unknown tags MAY be
ignored.
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Any update or retrieval requests for an Agent which does not exist
SHOULD respond with a 404 Not Found status code.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, July 2002.
11.2. Informative References
[I-D.davie-cdni-framework]
Davie, B., Ed. and L. Peterson, Ed., "Framework for CDN
Interconnection draft-davie-cdni-framework-01",
October 2011.
[I-D.ietf-cdni-requirements]
Leung, K. and Y. Lee, "Content Distribution Network
Interconnection (CDNI) Requirements
draft-ietf-cdni-requirements-02", December 2011.
[I-D.ietf-cdni-use-cases]
Bertrand, G., Stephan, E., Watson, G., Burbridge, T.,
Eardley, P., and K. Ma, "Use Cases for Content Delivery
Network Interconnection draft-ietf-cdni-use-cases-04",
March 2012.
Author's Address
Kevin J. Ma
Azuki Systems, Inc.
43 Nagog Park
Acton, MA 01720
USA
Phone: +1 978-844-5100
Email: kevin.ma@azukisystems.com
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