Content Delivery Network Interconnection (CDNI) Control Interface / Triggers 2nd Edition
draft-ietf-cdni-ci-triggers-rfc8007bis-15
| Document | Type | Active Internet-Draft (cdni WG) | |
|---|---|---|---|
| Authors | Nir Baruch Sopher , Ori Finkelman , Sanjay Mishra , Jay K. Robertson , Alan Arolovitch | ||
| Last updated | 2024-10-21 | ||
| Replaces | draft-ietf-cdni-triggers-extensions, draft-sopher-cdni-ci-triggers-rfc8007bis | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Associated WG milestone |
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| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-cdni-ci-triggers-rfc8007bis-15
Network Working Group N.B. Sopher
Internet-Draft O. Finkelman
Obsoletes: 8007 (if approved) Qwilt
Intended status: Standards Track S. Mishra
Expires: 24 April 2025 Verizon
J.K. Robertson
Qwilt
A. Arolovitch
Viasat
21 October 2024
Content Delivery Network Interconnection (CDNI) Control Interface /
Triggers 2nd Edition
draft-ietf-cdni-ci-triggers-rfc8007bis-15
Abstract
This document obsoletes RFC8007. The document describes the part of
Content Delivery Network Interconnection (CDNI) Control interface
that allows a CDN to trigger activity in an interconnected CDN that
is configured to deliver content on its behalf. The upstream CDN MAY
use this mechanism to request that the downstream CDN preposition
metadata or content as well as request that it invalidate or purge
metadata or content. The upstream CDN MAY monitor the status of
activity that it has triggered in the downstream CDN.
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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 24 April 2025.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
2. Model for CDNI Triggers . . . . . . . . . . . . . . . . . . . 5
2.1. REST Architecture . . . . . . . . . . . . . . . . . . . . 5
2.2. HTTP Methods . . . . . . . . . . . . . . . . . . . . . . 6
2.3. Trigger . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4. Trigger Collection . . . . . . . . . . . . . . . . . . . 7
2.5. Session Overview . . . . . . . . . . . . . . . . . . . . 7
2.6. Trigger Processing . . . . . . . . . . . . . . . . . . . 9
2.6.1. Timing and Order . . . . . . . . . . . . . . . . . . 9
2.6.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . 9
2.6.3. Results . . . . . . . . . . . . . . . . . . . . . . . 10
2.7. Trigger Extensibility . . . . . . . . . . . . . . . . . . 10
2.8. Multiple Interconnected CDNs . . . . . . . . . . . . . . 11
3. CDNI Trigger Interface . . . . . . . . . . . . . . . . . . . 13
3.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 14
3.2. Modifying Triggers . . . . . . . . . . . . . . . . . . . 15
3.3. Cancelling Triggers . . . . . . . . . . . . . . . . . . . 16
3.4. Checking Status . . . . . . . . . . . . . . . . . . . . . 16
3.4.1. Polling Trigger Collections . . . . . . . . . . . . . 17
3.4.2. Polling Triggers . . . . . . . . . . . . . . . . . . 18
3.5. Deleting Triggers . . . . . . . . . . . . . . . . . . . . 18
3.6. Expiry of Triggers . . . . . . . . . . . . . . . . . . . 19
3.7. Loop Detection and Prevention . . . . . . . . . . . . . . 19
3.8. Error Handling . . . . . . . . . . . . . . . . . . . . . 19
3.8.1. Error Propagation . . . . . . . . . . . . . . . . . . 20
4. CI/T Object Properties and Encoding . . . . . . . . . . . . . 23
4.1. Trigger Resource . . . . . . . . . . . . . . . . . . . . 24
4.1.1. Trigger Action . . . . . . . . . . . . . . . . . . . 26
4.1.2. Trigger Specs . . . . . . . . . . . . . . . . . . . . 27
4.1.3. Trigger Extensions . . . . . . . . . . . . . . . . . 35
4.1.4. Trigger State . . . . . . . . . . . . . . . . . . . . 48
4.1.5. Trigger Errors . . . . . . . . . . . . . . . . . . . 49
4.2. Trigger Collection Resource . . . . . . . . . . . . . . . 54
4.2.1. Filtered Collections by Status Link . . . . . . . . . 56
4.2.2. Filtered Collections by Label Link . . . . . . . . . 57
4.3. Other CI/T Objects . . . . . . . . . . . . . . . . . . . 57
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4.3.1. URL Type . . . . . . . . . . . . . . . . . . . . . . 57
4.3.2. ObjectList . . . . . . . . . . . . . . . . . . . . . 58
4.3.3. CDN Provider ID . . . . . . . . . . . . . . . . . . . 64
5. Footprint and Capabilities . . . . . . . . . . . . . . . . . 64
5.1. CI/T Endpoint Capability Object . . . . . . . . . . . . . 64
5.1.1. CI/T Endpoints Capability Object Serialization . . . 65
5.2. CI/T Trigger Scope Capability Object . . . . . . . . . . 66
5.2.1. CI/T Trigger Scope Capability Object Serialization . 68
5.3. CI/T Object List Type Capability Object . . . . . . . . . 68
5.3.1. CI/T Object List Type Capability Object
Serialization . . . . . . . . . . . . . . . . . . . . 69
5.4. CI/T Private URL Capability Object . . . . . . . . . . . 69
5.4.1. CI/T Private URL Type Capability Object
Serialization . . . . . . . . . . . . . . . . . . . . 69
5.5. CI/T Extended Status Capability Object . . . . . . . . . 70
5.5.1. CI/T Private URL Type Capability Object
Serialization . . . . . . . . . . . . . . . . . . . . 70
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 71
6.1.1. Preposition . . . . . . . . . . . . . . . . . . . . . 71
6.1.2. Invalidate . . . . . . . . . . . . . . . . . . . . . 73
6.1.3. Invalidation with Regex . . . . . . . . . . . . . . . 75
6.1.4. Preposition with ObjectLists . . . . . . . . . . . . 77
6.2. Examining Trigger Status . . . . . . . . . . . . . . . . 78
6.2.1. Collection of All Triggers . . . . . . . . . . . . . 78
6.2.2. Filtered Collections of Triggers . . . . . . . . . . 80
6.2.3. Individual Trigger Resources . . . . . . . . . . . . 81
6.2.4. Polling for Changes in Status . . . . . . . . . . . . 83
6.2.5. Deleting Triggers . . . . . . . . . . . . . . . . . . 85
6.2.6. Extensions with Error Propagation . . . . . . . . . . 87
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 90
7.1. CDNI Payload Type Parameter Registrations . . . . . . . . 90
7.1.1. CDNI ci-trigger.v2 Payload Type . . . . . . . . . . . 91
7.1.2. CDNI FCI CI/T Payload Types . . . . . . . . . . . . . 91
7.2. "CDNI CI/T Trigger Types" Registry For Trigger Actions . 92
7.3. "CDNI CI/T Trigger Specs" Registry . . . . . . . . . . . 92
7.4. "CDNI CI/T Trigger Subjects" Registry . . . . . . . . . . 93
7.5. "CDNI CI/T Object List Types" Registry . . . . . . . . . 93
7.6. "CDNI CI/T Trigger Extensions" Registry . . . . . . . . . 93
7.7. "CDNI CI/T Error Codes" Registry . . . . . . . . . . . . 94
7.8. "CDNI CI/T URL Types" Registry . . . . . . . . . . . . . 94
8. Security Considerations . . . . . . . . . . . . . . . . . . . 94
8.1. Authentication, Authorization, Confidentiality, Integrity
Protection . . . . . . . . . . . . . . . . . . . . . . . 95
8.2. Denial of Service . . . . . . . . . . . . . . . . . . . . 96
8.3. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 96
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 97
9.1. Normative References . . . . . . . . . . . . . . . . . . 97
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9.2. Informative References . . . . . . . . . . . . . . . . . 98
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 99
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 99
1. Introduction
[RFC6707] introduces the problem scope for Content Delivery Network
Interconnection (CDNI) and lists the four categories of interfaces
that may be used to compose a CDNI solution (Control, Metadata,
Request Routing, and Logging).
[RFC7336] expands on the information provided in [RFC6707] and
describes each of the interfaces and the relationships between them
in more detail.
The CDNI Control Interface / Triggers 1st edition [RFC8007],
deprecated by this document, describes the "CI/T" interface -- "CDNI
Control interface / Triggers". It does not consider those parts of
the Control interface that relate to configuration, bootstrapping, or
authentication of CDN Interconnect interfaces. Section 4 of
[RFC7337] identifies the requirements specific to the CI/T interface;
requirements applicable to the CI/T interface are CI-1 to CI-6.
This document is a second edition of the CDNI Control Interface /
Triggers, which defines a new version, "v2", of the interface
objects. The new objects replace the trigger interface's main
objects, the "ci-trigger-command" object and its matching "ci-
trigger-status" object with "ci-trigger.v2" object to support REST
[REST] architectural style in a way that improves the interface's
flexibility, extensibility and interoperability, and allows encoding
the interface using OpenAPI.
The second edition of the CI/T interface further allows use of
separate Control interface endpoints for content and metadata.
The document also provides a Trigger Extension mechanism that MAY be
used to provide further instruction on the trigger execution.
This second edition also includes cascaded CDN error propagation and
extended trigger status reporting for improved trigger execution
monitoring, as well as use of external object lists for improved
scale and integration of trigger-based APIs with existing content
workflows.
* Section 2 outlines the model for the CI/T interface at a high
level.
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* Section 3 defines the CI/T interface offered by the downstream
CDN.
* Section 4 defines encoding of the standard CI/T objects, and
introduces trigger spec and trigger extension types.
* Section 5 describes the FCI capabilities objects used to inform on
the supported CI/T-related capabilities.
* Section 6 contains example messages.
1.1. Terminology
This document reuses the terminology defined in [RFC6707] and uses
"uCDN" and "dCDN" as shorthand for "upstream CDN" and "downstream
CDN", respectively.
Additionally, the following terms are used throughout this document
and are defined as follows:
* HLS - HTTP Live Streaming
* DASH - Dynamic Adaptive Streaming Over HTTP
* MSS - Microsoft Smooth Streaming
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Model for CDNI Triggers
2.1. REST Architecture
The CI/T interface utilizes HTTP/1.1 protocol [RFC9112] and follows
the principles of the Representational State Transfer (REST)
architectural style. uCDN, in its capacity of a CI/T interface
client, makes a request to dCDN to carry out an action ("trigger")
related to metadata or content stored by dCDN on behalf of uCDN.
dCDN, as a CI/T interface server, governs the triggers as a set of
resources, which can be dynamically created and deleted, and whose
state can be retrieved and/or modified by uCDN. Each such trigger is
identified by a unique Uniform Resource Identifier (URI) is defined
in Section 4.2 of [RFC9110].
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Once a trigger is created, uCDN can retrieve its trigger state from
dCDN or request its state to be modified by transferring an updated
representation of the trigger state to dCDN. The CI/T interface
supports representation of trigger resources using JSON [RFC8259].
This RESTful data model built around a common "trigger" resource
replaces the command-oriented model of [RFC8007], wherein uCDN passed
commands to dCDN using "ci-trigger-command" objects, and dCDN
generated "ci-trigger-status" objects in response.
2.2. HTTP Methods
Section 9.3 of [RFC9110] defines the set of methods in HTTP. The CI/
T interface uses some of these methods for resource creation,
retrieval of resource state, modification of resources and deletion
of resources. The HTTP methods not listed here are not supported by
the CI/T interface.
* GET - used to retrieve the current state of a resource. The GET
method doesn't cause any state change on the server side.
* POST - used to request that the target resource process the
representation enclosed in the request. If a resource has been
created on the server as a result of successfully processing a
POST request, the server sends a 201 (Created) response containing
a Location header field that contains an identifier for the newly
created resource.
* DELETE - used to request the server remove the target resource.
* HEAD - used to request metadata associated with the target
resource, in the form of HTTP response headers that would have
been sent if the GET method was used instead. The HEAD method can
be used to verify that the target resource exists at the server.
2.3. Trigger
To request that an action be carried by dCDN, uCDN requests to create
a trigger resource. If dCDN accepts the request, it creates a new
Trigger resource and returns its unique URI to uCDN. uCDN MUST use
this URI for all requests associated with the created Trigger
resource.
uCDN can only access Trigger resources it created.
Note that the version of the Trigger resources that uCDN requests to
create MUST match the version of CI/T Trigger objects reported as
supported by dCDN.
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The CI/T interface supports the following types of trigger action::
* preposition - used to instruct dCDN to fetch metadata from the
uCDN or content from any origin including uCDN.
* invalidate - used to instruct dCDN to revalidate specific metadata
or content before reusing it.
* purge - used to instruct dCDN to delete specific metadata or
content.
Note that additional action types can be defined and registered in
the future.
The trigger resource has a state attribute. dCDN creates new
triggers in "pending" state. Once dCDN starts processing a trigger,
the trigger state is set to "active". Once the the trigger
processing is complete, the state is set to either "complete" or
"failed", depending on the processing outcome.
uCDN MAY request dCDN to cancel a trigger. If such request is
accepted, the trigger state is changed to "cancelling", and when the
cancellation is complete, the trigger state changes to "cancelled".
For full description of the Trigger resource, please refer to
Section 4.1.
2.4. Trigger Collection
Trigger Collection is a resource that represents one or more trigger
resources, belonging to particular uCDN. dCDN maintains one Trigger
Collection resource for each uCDN. Each uCDN only has access to its
own collection resource. dCDN supports retrieval of multiple
representations of the trigger collection resource. The supported
trigger collection representations are listed in Section 4.2, and
include filtering of Trigger resources by Trigger State and Trigger
Label attributes. Note that additional trigger collection
representations can be defined and registered in the future.
2.5. Session Overview
Figure 1 is an example showing the basic message flow in a CI/T
interface session used by the uCDN to trigger activity in dCDN and
for uCDN to discover the status of that activity. Only successful
triggering is shown. Examples of the messages are shown in
Section 6.
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uCDN dCDN
| (1) POST https://dcdn.example.com/triggers/uCDN |
[ ] --------------------------------------------------> [ ]--+
| [ ] | (2)
| (3) HTTP 201 Response [ ]<-+
[ ] <-------------------------------------------------- [ ]
| Loc: https://dcdn.example.com/triggers/uCDN/123 |
| |
. . .
. . .
. . .
| |
| (4) GET https://dcdn.example.com/triggers/uCDN/123 |
[ ] --------------------------------------------------> [ ]
| [ ]
| (5) HTTP 200 Trigger resource representation [ ]
[ ] <-------------------------------------------------- [ ]
| |
| |
| (6) DELETE https://dcdn.example.com/triggers/uCDN/123 |
[ ] --------------------------------------------------> [ ]--+
| [ ] | (7)
| (8) HTTP 200 OK [ ]<--
[ ] <-------------------------------------------------- [ ]
| |
Figure 1: Basic CDNI Message Flow for Triggers
The steps in Figure 1 are as follows:
1. uCDN requests to create a new Trigger resource by POSTing its
representation to the trigger collection resource with a well-
known URI "https://dcdn.example.com/triggers/uCDN".
2. dCDN authenticates the request, validates the Trigger resource in
it, and if the request is accepted, creates a new Trigger
resource.
3. dCDN responds to uCDN with an HTTP 201 response status and the
location of the Trigger resource.
4. uCDN MAY query, possibly repeatedly, the Trigger resource in
dCDN.
5. dCDN responds to each query with the current Trigger resource
representation, including the trigger state, that reflects the
progress of the uCDN request.
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6. Once the trigger reaches a terminal state ("complete", "failed"
or "cancelled"), uCDN MAY request to delete Trigger resource.
7. dCDN validates the request and the trigger resource state. If
successful, the trigger resource is removed by the server, and
subsequent requests for this resource MUST result in 404 (Not
Found).
8. dCDN responds to the deletion request with 200 (OK) status code.
2.6. Trigger Processing
2.6.1. Timing and Order
uCDN MAY place limits on timing and order of execution of a trigger
through optional TimePolicy (Section 4.1.3.3.2) and/or
ExecutionPolicy (Section 4.1.3.3.3) extensions. If neither of these
extensions are present in the trigger resource, the timing and order
of the trigger execution is under dCDN's control, including start
time, pacing of the activity in the network and order in which dCDN
chooses to process pending triggers.
The CI/T "invalidate" and "purge" trigger actions MUST be applied to
all data acquired before dCDN begins the trigger processing (i.e.
enters "active" state). dCDN implementation SHOULD apply
"invalidate" and "purge" triggers to content acquisition that is in
progress when the trigger becomes active, to avoid placing purged or
invalidated content into cache upon completion of the content
acquisition. dCDN SHOULD NOT apply CI/T "invalidate" and "purge"
actions to data acquired after the trigger processing started, but
this may not always be achievable, so uCDN cannot count on that.
If uCDN wishes to invalidate or purge content and then immediately
preposition replacement content at the same URLs, it SHOULD ensure
that dCDN has completed the invalidate/purge before initiating the
prepositioning. Otherwise, there is a risk that the dCDN
prepositions the new content, then immediately invalidates or purges
it (as a result of the two uCDN requests running in parallel). uCDN
MAY use the Execution Policy (Section 4.1.3.3.3) extension to
condition the start of preposition trigger processing on completion
of the earlier invalidate/purge trigger(s).
2.6.2. Scope
Each trigger can operate on multiple metadata and content elements,
usually referred to by their URLs. These elements are targeted by
specifying both their subject (i.e., "metadata" or "content") as well
as specification method (e.g., URL Regexes) and value.
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Multiple representations of an HTTP resource may share the same URL.
Triggers that invalidate or purge metadata or content apply to all
resource representations with matching URLs.
2.6.3. Results
Possible trigger states are defined in Section 4.1.4.
Trigger state MUST NOT be reported as "complete" until all operations
listed in the trigger have been completed successfully. The reasons
for failure, and URLs or patterns affected, SHOULD be made available
in the trigger state representation. For more details, see
Section 3.8.
2.7. Trigger Extensibility
The CDNI Control Interface / Triggers 1st edition [RFC8007] defines a
set of properties and objects used by the trigger commands. This 2nd
edition defines an extension mechanism to the triggers interface that
enables applications to add instructions for finer control over the
trigger execution, for example indicating a time window in which to
execute the trigger. This document specifies a generic trigger
extension object wrapper for managing individual CDNI trigger
extensions in an opaque manner.
All trigger extensions are optional, and it is thus the
responsibility of the extension specification to define a consistent
default behavior for the case the extension is not present.
All trigger extensions MUST be registered in the IANA "CDNI CI/T
Trigger Extensions" registry (see Section 7.6).
This document also defines an initial set of trigger extension
objects and registers them in the IANA "CDNI CI/T Trigger Extensions"
registry:
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+==================+=========================================+
| JSON String | Description |
+==================+=========================================+
| location-policy | Allowing the control over the locations |
| | in which the trigger is executed. |
+------------------+-----------------------------------------+
| time-policy | Allowing the scheduling of a trigger to |
| | run in a specific time window. |
+------------------+-----------------------------------------+
| execution-policy | Allowing the control over the order and |
| | timing in which triggers are executed. |
+------------------+-----------------------------------------+
Table 1
Example use cases
* Preposition with cache location policy
* Purge content with cache location policy
* Preposition at a specific time
* Purge by content acquisition time (e.g., purge all content
acquired in the past X hours)
2.8. Multiple Interconnected CDNs
In a network of interconnected CDNs, a single uCDN will originate a
given item of metadata and associated content. It MAY distribute
that metadata and content to one or more dCDNs, which in turn
distributes that metadata and content to additional dCDNs located
further downstream.
An intermediate CDN is dCDN that passes on CDNI Metadata and content
to dCDNs located further downstream.
A "diamond" configuration is one where dCDN can acquire metadata and
content originated in one uCDN from that uCDN itself and an
intermediate CDN, or via more than one intermediate CDN.
Triggers originating in the single source uCDN affect metadata and
content in all dCDNs; however, in a diamond configuration, it may not
be possible for dCDN to determine from which uCDN it acquired
content. In this case, dCDN MUST allow each uCDN from which it may
have acquired the content to act upon that content using triggers.
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In all other cases, dCDN MUST reject triggers from uCDN that attempts
to act on another uCDN's content by responding, for example, with an
HTTP 403 ("Forbidden").
Security considerations are discussed further in Section 8.
The diamond configuration may lead to inefficient interactions, but
the interactions are otherwise harmless. For example:
* When uCDN requests to create an "invalidate" trigger, dCDN will
receive that request from multiple directly connected uCDNs. The
dCDN may schedule multiple such triggers separately, and the last
scheduled trigger may affect content already revalidated following
execution of the "invalidate" trigger that was scheduled first.
* If one of dCDN's directly connected uCDNs loses its rights to
distribute content, it may issue a "purge" trigger. That purge
may affect content dCDN could retain because it's distributed by
another directly connected uCDN. But, that content can be
reacquired by dCDN from the remaining uCDN.
* When uCDN originating an item of content issues a purge followed
by a preposition, two directly connected uCDNs will pass those
triggers to a dCDN. That dCDN implementation need not merge those
operations or notice the repetition, in which case the purge
issued by one uCDN will be completed before the other. The first
uCDN to finish its purge may then forward the "preposition"
trigger, and content prepositioned as a result might be affected
by the still-running purge issued by the other uCDN. However,
dCDN will reacquire that content as needed, or when it's asked to
preposition the content by the second uCDN. dCDN implementation
could avoid this interaction by knowing which uCDN it acquired the
content from, or it could minimize the consequences by recording
the time at which the "invalidate"/"purge" trigger was received
and not applying it to content acquired after that time.
If dCDN is also acting as uCDN in a cascade, it MUST forward trigger
requests to any dCDNs that may be affected. The trigger state MUST
NOT be reported as "complete" by an intermediate CDN until it is
"complete" in all of its dCDNs and in the intermediate CDN itself.
If a trigger is reported as "processed" in the intermediate CDN or
any one of its dCDNs, intermediate CDNs MUST report trigger as
"processed" as well. If a trigger is reported as "failed" by the
intermediate CDN or any one of its dCDNs, the intermediate CDN must
report the trigger as "failed" only after its processing is finished
in it and all of its dCDNs. A cancelled trigger MUST be reported as
"cancelling" until it has been reported as "cancelled", "complete",
or "failed" by all dCDNs in a cascade.
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3. CDNI Trigger Interface
This section describes an interface to enable uCDN to trigger
activity in dCDN.
The CI/T interface builds on top of HTTP, so dCDNs may make use of
any HTTP feature when implementing the CI/T interface. For example,
dCDN SHOULD make use of HTTP's caching mechanisms to indicate that a
requested resource representation has not been modified, reducing
uCDN's processing needed to determine whether the status of a trigger
has changed.
dCDNs MAY implement separate CI/T interfaces per Section 4.1.2.2,
i.e. one CI/T interface for trigger operations on metadata and
another for operations on content. In this case, dCDN MUST advertise
separate interface endpoints via Section 5.1.
All dCDNs implementing CI/T MUST support the HTTP GET, HEAD, POST,
and DELETE methods as defined in [RFC9110].
The only resource representation specified in this document is JSON
[RFC8259]. It MUST be supported by uCDN and by dCDN.
The CI/T interface uses a root URL for retrieval of the Trigger
Collection resource and creation of new triggers. The mechanism for
discovery of that URL is part of the CI/T interface bootstrapping and
is outside the scope of this document.
uCDN requests to create a new Trigger resource by POSTing its
representation to the root interface URL, discovered at the time of
interface bootstrapping, e.g. "https://dcdn.example.com/triggers/
uCDN". If the request is accepted by dCDN, it creates a new Trigger
resource and returns its URI to uCDN in an HTTP 201 response.
Once created, the new trigger URI also becomes available via the
trigger collection resource described in Section 4.2. Additionally,
uCDN may discover the URIs of multiple trigger collection
representations using the interface root URL. This means that the
URIs for all trigger resources and trigger collection representations
can be discovered by uCDN, so dCDNs are free to assign whatever
structure they desire to the URIs for CI/T resources. Therefore,
uCDNs MUST NOT make any assumptions regarding the structure of CI/T
URIs or the mapping between CI/T objects and their associated URIs.
The URIs used in the examples in this document are purely
illustrative and are not intended to impose a definitive structure on
CI/T interface implementations.
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3.1. Creating Triggers
To create a new trigger, uCDN makes an HTTP POST request with the
trigger representation to the root interface URL. The trigger
representation MUST include the mandatory attributes of trigger
resource (Section 4.1).
uCDN MAY also optionally specify optional trigger v2 specification
attributes, namely trigger labels and trigger extensions, as well as
the optional "cdn-path" attribute of the trigger resource.
dCDN validates the trigger resource representation sent by uCDN. If
the representation is malformed or uCDN does not have sufficient
access rights, dCDN MUST either respond with an appropriate 4xx HTTP
error code and not create a trigger resource or create a trigger
resource with "failed" state and an appropriate Error.v2 Description
(Section 4.1.5.1).
The new trigger resource is created in "pending" state. If
successful, The HTTP response to the uCDN trigger creation request
MUST have status code 201 (Accepted) and MUST convey the URI of the
newly created trigger resources in the Location response header field
[RFC9110]. The HTTP response SHOULD include the updated
representation of the trigger resource. This is particularly
important in cases where dCDN processed the trigger immediately.
Once a trigger resource has been created, dCDN MUST NOT reuse its
URI, even after the trigger resource has been fully removed. It is
therefore recommended that dCDN utilize unique UUID identifiers as
specififed in [RFC9562].
dCDN SHOULD provide continuous updates of the trigger processing
progress, by responding with updated trigger resource representations
to subsequent uCDN requests sent to the created trigger URL. If the
dCDN is unable to do that, it MUST indicate that it has accepted the
request but will not be providing further status updates. To do
this, it MUST set the trigger state to "processed" at creation time.
In this case, CI/T processing should continue as it were a request in
the "complete" state. In this case dCDN SHOULD also provide an
estimated completion time for the request by using the trigger
"etime" property.
Otherwise dCDN MUST set the state of the new trigger to "pending".
Once trigger processing has started, the status MUST be changed to
"active". Finally, once the the trigger processing is complete, the
trigger state MUST be set to "complete" or "failed".
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Once created, trigger resources can be cancelled, modified or deleted
by uCDN, subject to constraints described below.
3.2. Modifying Triggers
Modification of existing triggers is useful for uCDN to correct an
error in trigger specification or trigger extension(s) that may
govern when the trigger is to be processed.
uCDN can request modification of an existing trigger resource by
sending an updated trigger representation to the trigger URI using
HTTP POST command.
dCDN MAY accept modifications of the trigger specifications, trigger
extensions and trigger labels, when the trigger is in "pending"
state, i.e. dCDN didn't start its processing yet.
dCDN MAY also accept a request to change the trigger state subject to
the following constraints:
* the requested state is "cancelled", and the trigger was in either
"pending" or "active" state when dCDN receives the request
* the requested state is "active", and the trigger was in "pending"
state when dCDN received the request
The Section 3.3 describes processing of the trigger cancellation
requests in detail. uCDN MAY request to set the trigger state to
"active" to prompt dCDN to re-examine the trigger resource and start
its processing immediately.
dCDN MUST respond to the trigger modification request appropriately.
Thus, the HTTP status code 200 ("OK") should be returned if the
modification has been processed, 202 ("Accepted") if the command has
been accepted but the modification is not fully complete yet, 404
("Not Found") when the trigger resource does not exist, 409
("Conflict") when the trigger resource is in a state that doesn't
allow the requested modification, 501 ("Not Implemented") if the
modification is not supported by dCDN or an appropriate 4xx HTTP
error code in case of a malformed request.
In case of successful 2xx response, dCDN MUST provide the updated
trigger resource representation in the response body.
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3.3. Cancelling Triggers
uCDN MAY request cancellation of a trigger by requesting its state to
be set to "cancelled", as described in Section 3.2. dCDN MUST
respond to such request, however the actual cancellation of a trigger
resource is optional to implement.
dCDN MUST respond to the trigger cancellation request appropriately.
dCDN MUST respond with the HTTP status code 200 ("OK") if the trigger
processing has been cancelled and the trigger state has been set to
"cancelled", 202 ("Accepted") if the command has been accepted but
the trigger processing has not been cancelled yet, 404 ("Not Found")
when the trigger resource does not exist, or 501 ("Not Implemented")
if cancellation is not supported by dCDN.
If cancellation of a "pending" trigger is accepted by dCDN, dCDN
SHOULD NOT start the processing of that activity. Requesting a
cancellation of a "pending" trigger does not, however, guarantee that
the corresponding activity will not be started, because uCDN cannot
control the timing of that activity. Processing could, for example,
start after the POST is sent by uCDN but before that request is
processed by dCDN.
If cancellation of an "active" or "processed" trigger is accepted by
dCDN, dCDN SHOULD stop processing the trigger. However, as with the
cancellation of a "pending" trigger, dCDN does not guarantee that the
trigger processing doesn't run to completion in the meantime.
If uCDN cannot stop the trigger processing immediately after
receiving the request from uCDN to do so, it MUST set the trigger
state to "cancelling" and provide this state in the trigger
representation in its response. If the trigger processing is stopped
before its normal completion, the trigger state MUST be set to
"cancelled".
Cancellation of a "complete", "failed" or "cancelled" trigger
requires no processing in dCDN. Its state MUST NOT be changed.
3.4. Checking Status
uCDN has two ways to check the progress of its triggers' processing,
as described in Section 3.4.1 and Section 3.4.2.
To allow uCDN to use client-side caching of all triggers and trigger
collections, dCDN SHOULD include an ETag response header with every
resource representation it sends. dCDN SHOULD also respond with the
HTTP code 304 ("Not Modified") without a response body in response to
conditional resource requests that use "If-None-Match" and/or "If-
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Modified-Since" request headers as described in Section 13 of
[RFC9110] , in case dCDN doesn't have a more recent resource
representation.
dCDN SHOULD use the cache control headers for responses to GET
requests for its resources to indicate the frequency at which it
recommends that uCDN and/or intermediate proxies should poll for
change. If provided, uCDN should match the frequency of polling to
the cache control information provided by dCDN.
3.4.1. Polling Trigger Collections
uCDN MAY fetch the trigger collection or one of filtered
representations of it. This makes it possible for uCDN to poll the
status of all trigger resources or selected trigger subsets, filtered
by trigger state or by trigger label. In this way, uCDN is able to
monitor trigger state changes by polling the representation of the
trigger collection filtered by trigger state.
3.4.1.1. Trigger resource collection: extended view representation
If dCDN advertises support for extended status, uCDN MAY request the
extended trigger collection representation, which embeds full
representations of trigger resources in the collection resource. The
extended representation is supported for all filtered representations
of the trigger collection, so it is possible to retrieve all trigger
resource representations for a specific trigger state (e.g. all
triggers in "pending" state).
uCDN SHOULD request the extended representation by passing the query
string parameter "status=extended" when requesting a trigger
collection resource or one of its filtered representations. dCDN
SHOULD appropriately respond to the request for extended status with
HTTP Status 200 ("OK") when such request can be satisfied, with error
code 501 ("Not Implemented") if the capability has not been
implemented or advertised, and 400 ("Bad Request") when dCDN
encounters a malformed query format.
By default, trigger resources are represented in the trigger
collection with their resource URL only.
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3.4.2. Polling Triggers
uCDN has a URI provided by dCDN at the trigger creation time.
Alternatively, uCDN MAY discover trigger resource URI by retrieving
the trigger collection resource and/or one of its filtered
representations. It may fetch an up-to-date representation of the
trigger resource at any time using HTTP GET request, including
changes in trigger state, as well as the outcome of the trigger
processing.
3.5. Deleting Triggers
uCDN MAY request delete trigger resources at any time using the HTTP
DELETE method. As defined in the CDNI Control Interface / Triggers
1st edition [RFC8007],
Once deleted, the deleted trigger MUST be removed from all
representations of the trigger collection. Subsequent requests to
the trigger resource URI MUST be rejected by dCDN with HTTP error 404
("Not Found").
the effect of deletion is similar to cancellation, except that the
trigger resource becomes unavailable after the deletion is complete.
For this reason, uCDN SHOULD cancel triggers rather than delete them
when it is important for uCDN to access the trigger status after the
trigger processing is stopped.
If a "pending" trigger is deleted, dCDN SHOULD NOT start the
processing of that activity. Deleting a "pending" trigger does not,
however, guarantee that its processing has not started, because uCDN
cannot control the timing of that activity. Processing may, for
example, start after the DELETE is sent by uCDN but before that
request is processed by dCDN.
When an "active" or "processed" trigger is deleted, the dCDN SHOULD
stop processing it. However, as with deletion of a "pending"
trigger, dCDN does not guarantee this.
Deletion of a "complete", "cancelled" or "failed" trigger no
processing in dCDN.
dCDN MUST respond to the trigger deletion request appropriately.
dCDN MUST respond with the HTTP status code 200 ("OK") without a
response body if the trigger has been deleted immediately. 202
("Accepted") if the command has been accepted but the trigger has not
been deleted yet. 404 ("Not Found") when the trigger resource does
not exist, or 501 ("Not Implemented") if deletion is not supported by
dCDN.
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The trigger state MUST be set to "cancelling" while dCDN is
processing a deletion request asynchronously.
3.6. Expiry of Triggers
dCDN MAY automatically delete trigger resources sometime after they
reach a terminate state (one of "complete", "processed", "failed", or
"cancelled"). In this case, after dCDN removed such trigger, it MUST
respond to subsequent requests for it with the HTTP error 404 ("Not
Found") and remove it from the trigger collection resource.
If dCDN does remove triggers in a terminal state automatically, it
MUST report the expiry timeout period, using an attribute of the
trigger collection resource.
It is RECOMMENDED that dCDN sets its expiry timeout to at least 24
hours. It is further RECOMMENDED that uCDN sets its trigger polling
period to less than the expiry period, so it doesn't miss trigger
status updates before the "complete" or "failed" triggers are expired
by dCDN.
3.7. Loop Detection and Prevention
Given three CDNs, A, B, and C, if CDNs B and C delegate delivery of
CDN A's content to each other, CDN A's trigger creation requests
could be passed between CDNs B and C in a loop. More complex
networks of CDNs could contain similar loops involving more hops.
To prevent and detect such CI/T loops, each CDN uses a CDN Provider
ID (PID) (Section 4.3.3). to uniquely identify itself. In every
trigger resource it creates or cascades, each CDN MUST append an
array element containing its CDN PID to a JSON array under an entry
named "cdn-path". When receiving a trigger creation request, dCDN
MUST check the cdn-path and reject any trigger that already contains
its own CDN PID in the cdn-path. Transit CDNs MUST check the "cdn-
path" and not cascade the trigger creation request to dCDNs that are
already listed in the cdn-path.
3.8. Error Handling
dCDN MAY reject CI/T interface requests, by responding to those
requests with 4xx or 5xx HTTP status codes. For example, uCDN MAY
respond with 400 ("Bad Request") if the request is malformed, or 403
("Forbidden") or 404 ("Not Found") if the request could not be
properly authenticated or if uCDN is trying to act on another CDN's
resources.
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If any part of the trigger processing fails, the trigger SHOULD be
reported as "failed" once its activity is complete or if no further
errors will be reported. The "errors" property in the trigger will
be used to enumerate which actions failed and the reasons for
failure, and can be present while the trigger is still "pending" or
"active" if the trigger processing is still running for some URLs or
patterns in the trigger specs.
Once a request has been accepted, processing errors are reported in
the trigger using a list of Error.v2 Descriptions. Each Error.v2
Description is used to report errors against one or more of the URLs
or patterns in the Trigger Specification.
If a Surrogate affected by a trigger is offline in the dCDN or dCDN
is unable to pass a trigger on to any of its cascaded dCDNs:
* If the trigger is abandoned by dCDN, dCDN SHOULD report an error.
* A CI/T "invalidate" command may be reported as "complete" when
Surrogates that may have the data are offline. In this case,
Surrogates MUST NOT use the affected data without first
revalidating it when they are back online.
* CI/T "preposition" and "purge" commands can be reported as
"processed" if affected caches are offline and the activity will
complete when they return to service.
* Otherwise, dCDN SHOULD keep the trigger "pending" or "active"
state until either the trigger is acted upon or uCDN chooses to
cancel it.
3.8.1. Error Propagation
This subsection explains the mechanism for enabling uCDN to trace an
error back to dCDN in which it occurred. CDNI triggers may be
propagated over a chain of downstream CDNs. For example, an upstream
CDN A (uCDN-A) that is delegating to a downstream CDN B (dCDN-B) and
dCDN-B is delegating to a downstream CDN C (dCDN-C). Triggers sent
from uCDN-A to dCDN-B may be redistributed from dCDN-B to dCDN-C, and
errors can occur anywhere along the path. Therefore, it might be
essential for uCDN-A that sets the trigger, to be able to trace back
an error to the downstream CDN where it occurred. This document adds
a mechanism to propagate the PID of dCDN where the fault occurred,
back to the uCDN by adding the PID to the error.v2 description. When
dCDN-B propagates a trigger further to the downstream dCDN-C, it MUST
also propagate back the errors received in the trigger status
resource from dCDN-C by adding them to the errors array in its own
status resource to be sent back to the originating uCDN-A. While
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propagating back the errors dCDN-B MAY also specify dCDN-C PID,
indicating to which CDN the error specifically relates. The trigger
originating upstream CDN then receives an array built of the errors
that occurred in all the CDNs along the execution path, where each
error MAY carry its own CDN identifier.
Figure 2 below is an example showing the message flow used by uCDN-A
to trigger activity in dCDN-B, followed by dCDN-C, as well as the
discovery of the status of that activity, including the Error
Propagation.
uCDN-A dCDN-B dCDN-C
| | |
| (1) POST | |
| https://dcdn-b.example.com | |
| /triggers/uCDN-A | |
[ ]--------------------------->[ ]--+ |
| [ ] | (2) |
| [ ]<-+ |
| (3) HTTP 201 Response. [ ] |
|<----------------------------[ ] |
| Loc: [ ] |
| https://dcdn-b.example.com [ ] (4) POST |
| /triggers/uCDN-A/123 [ ] https://dcdn-c.example.com |
| [ ] /triggers/dCDN-B | (5)
| [ ]--------------------------->[ ]--+
| | [ ] |
| | [ ]<-+
| | (6) HTTP 201 Response. [ ]
| [ ]<---------------------------[ ]
| | Loc: |
| | https://dcdn-c.example.com |
| | /triggers/dCDN-B/456 |
| | |
| [ ]--+ |
| [ ] | (7.1) |
| [ ]<-+ [ ]--+
| | (7.2) [ ] |
| | [ ]<-+
| | |
. . .
. . .
. . .
| | (8) GET |
| | https://dcdn-c.example.com |
| | /triggers/dCDN-B/456 |
| [ ]--------------------------->[ ]
| | [ ]
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| | (9) HTTP 200 [ ]
| | Trigger resource [ ]
| [ ]<---------------------------[ ]
| | |
. . .
. . .
. . .
| (10) GET | |
| https://dcdn-b.example.com | |
| /triggers/uCDN-A/123 | |
[ ]--------------------------->[ ] |
| [ ] |
| (11) HTTP 200 [ ] |
| Trigger resource [ ] |
[ ]<---------------------------[ ] |
Figure 2: CDNI Message Flow for Triggers, Including Error Propagation
The steps in Figure 2 are as follows:
1. uCDN-A triggers an action in dCDN-B by POSTing a trigger
representation to a triggers collection URI "https://dcdn-
b.example.com/triggers/uCDN-A". This URL was given to uCDN-A
when the CI/T interface was established.
2. dCDN-B authenticates the request, validates the trigger creation
request, and, if it accepts the request, creates a new trigger
resource.
3. dCDN-B responds to uCDN-A with an HTTP 201 response status and
the location of the newly created trigger.
4. dCDN-B triggers the action in dCDN-C by POSTing a trigger
representation to a triggers collection URI "https://dcdn-
c.example.com/triggers/dCDN-B". This URL was given to dCDN-B
when the CI/T interface was established.
5. dCDN-C authenticates the request, validates the trigger creation
request, and, if it accepts the request, creates a new trigger
resource.
6. dCDN-C responds to dCDN-B with an HTTP 201 response status and
the location of the newly created trigger resource.
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7. dCDN-C acts upon the trigger. However, the command fails at
dCDN-C as, for example, the trigger definition contains an
"action" type that is not supported by dCDN-C. dCDN-C's action
is depicted by 7.2 in the diagram, while 7.1 shows dCDN-B acting
on its own trigger.
8. dCDN-B queries, possibly repeatedly, the trigger resource in
dCDN-C.
9. dCDN-C responds with the trigger resource representation,
describing the progress or results of the trigger processing.
In the described flow, the trigger state is "failed", with an
Error.v2 Description object holding "eunsupported" Error Code
reflecting the reason.
10. uCDN-A queries, possibly repeatedly, the trigger status in dCDN-
B.
11. dCDN-B responds with the updated trigger resource
representation, describing the progress or results of trigger
processing. In the flow described above, the trigger state is
"failed", and the "eunsupported" error received in the trigger
status from dCDN-C is propagated along with dCDN-C PID by adding
it to the errors array in dCDN-B's own status resource to be
sent back to the originating uCDN-A.
4. CI/T Object Properties and Encoding
Trigger and Trigger Collection resources as well as their properties,
are encoded using JSON, as defined in Section 4.1, and Section 4.2,
respectively. When sending the JSON-based representation of these
resources, the MIME media type "application/cdni" MUST be used, with
parameter "ptype" values as defined below and in Section 7.1.
Names in JSON are case-sensitive. The names and literal values
specified in the present document MUST always use lowercase.
JSON types, including "object", "array", "number", and "string", are
defined in [RFC8259].
Unrecognized name/value pairs in JSON objects SHOULD NOT be treated
as an error by either uCDN or dCDN. They SHOULD be ignored during
processing and passed on by dCDN to any further dCDNs in a cascade.
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4.1. Trigger Resource
Trigger resource is encoded as a JSON object and MUST use a MIME
media type of "application/cdni; ptype=ci-trigger.v2". The rigger
resource contains the following name/value pairs:
Name: action
Description: Defines the type of the CI/T Trigger Action.
Value: Trigger Action Type, as defined in Section 4.1.1.
Mandatory: Yes.
Name: specs
Description: Array of trigger specs representing the trigger's
targets, as described in Section 4.1.2.
Value: Array of GenericTriggerSpec objects (see
Section 4.1.2.1).
Mandatory: Yes. Furthermore, the list MUST NOT be empty.
Name: extensions
Description: Array of trigger extensions, as described in
Section 4.1.3.
Value: Array of GenericTriggerExtension objects (see
Section 4.1.3.2).
Mandatory: No. The default is no extensions.
Name: labels
Description: Array of trigger labels.
Value: Array of Trigger labels, Each label is encoded as a JSON
string and SHOULD be unique per trigger.
Mandatory: No. The default is no labels.
Name: cdn-path
Description: The chain of CDN PIDs of CDNs that have already
created this trigger resource.
Value: Non-empty array of JSON strings, where each string is a
CDN PID as defined in Section 4.3.3.
Mandatory: No. The default is no CDN path.
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Name: ctime
Description: The time at which the trigger resource was
received by the dCDN. The time is determined by dCDN; there is
no requirement to synchronize clocks between interconnected
CDNs.
Value: A JSON number, seconds since the UNIX epoch (00:00:00
UTC on 1 January 1970).
Mandatory: Yes.
Name: mtime
Description: The time at which the trigger resource was last
modified. The time is determined by dCDN; there is no
requirement to synchronize clocks between interconnected CDNs.
Value: A JSON number, seconds since the UNIX epoch (00:00:00
UTC on 1 January 1970).
Mandatory: Yes.
Name: etime
Description: The estimate of the time at which dCDN expects to
complete the trigger processing. Time is determined by dCDN;
there is no requirement to synchronize clocks between
interconnected CDNs.
Value: A JSON number, seconds since the UNIX epoch (00:00:00
UTC on 1 January 1970).
Mandatory: No.
Name: state
Description: The current trigger state.
Value: Trigger state, as defined in Section 4.1.4.
Mandatory: No.
Name: state-reason
Description: A human-readable explanation for the object state.
Value: A JSON string, the human-readable reason.
Mandatory: No.
Name: errors
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Description: Descriptions of errors that have occurred while
processing the trigger.
Value: An array of Error.v2 Descriptions, as defined in
Section 4.1.5.1. An empty array is allowed and is equivalent
to omitting "errors" from the object.
Mandatory: No.
Name: objects
Description: List of objects derived by dCDN when processing
the trigger.
Value: An array of ObjectList (Section 4.3.2) objects. dCDN
SHOULD provide the list of objects it used as input for
processing the trigger with Section 4.1.2.7, provided that dCDN
advertised support for extended status (Section 5.5). An empty
array is allowed and is equivalent to omitting "objects" from
the trigger representation. This field is intended to provide
the list of all objects used in processing. The objects that
failed to process SHOULD be specified using the Error.v2
Description resource.
Mandatory: No.
4.1.1. Trigger Action
Trigger Action is used in a trigger resource to describe trigger
actions. It was initially referred to in [RFC8007] as "Trigger
Type".
All trigger actions MUST be registered in the IANA "CDNI CI/T Trigger
Types" registry (see Section 7.2).
dCDN receiving a request containing a trigger action that it does not
recognize or does not support MUST reject the request by creating a
trigger with "failed" state and the "errors" array containing an
Error.v2 Description with error "eunsupported" (see Section 4.1.5.2).
The following trigger actions are defined by this document:
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+=============+============================================+
| JSON String | Description |
+=============+============================================+
| preposition | A request for dCDN to acquire metadata or |
| | content. |
+-------------+--------------------------------------------+
| invalidate | A request for dCDN to invalidate metadata |
| | or content. After servicing this request, |
| | dCDN will not use the specified data |
| | without first revalidating it using, for |
| | example, an "If-None-Match" HTTP request. |
| | dCDN need not erase the associated data. |
+-------------+--------------------------------------------+
| purge | A request for dCDN to erase metadata or |
| | content. After servicing the request, the |
| | specified data MUST NOT be held on dCDN |
| | (dCDN should reacquire the metadata or |
| | content from uCDN if it needs it). |
+-------------+--------------------------------------------+
Table 2
4.1.2. Trigger Specs
The CDNI Control Interface / Triggers 1st edition [RFC8007] defines a
set of properties and objects used by the trigger commands in order
to specify the targets upon which the trigger is applied. This
document modifies the trigger interface objects so it has a list of
trigger specs. Such structure improves the interface's extensibility
and flexibility. Furthermore, the document defines a generic trigger
spec object that acts as a wrapper for managing individual CDNI
trigger specs in an opaque manner, allowing future extension of the
interface.
All trigger specs MUST be registered in the IANA "CDNI CI/T Trigger
Specs" registry (see Section 7.3).
dCDN receiving a trigger creation request containing a trigger spec
that it does not recognize or does not support MUST reject the
request by creating a trigger resource with "failed" state and the
"errors" array containing an Error.v2 Description with error "espec"
(see Section 4.1.5.2).
This document also defines an initial set of trigger spec objects and
registers them in the IANA "CDNI CI/T Trigger Specs" registry:
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+====================+========================================+
| JSON String | Description |
+====================+========================================+
| urls | Allowing the specification of trigger |
| | targets via URLs. |
+--------------------+----------------------------------------+
| ccids | Allowing the specification of trigger |
| | targets via CCIDs content grouping, as |
| | defined in section 4.2.8 [RFC8006]. |
+--------------------+----------------------------------------+
| uri-pattern-match | Allowing the specification of trigger |
| | targets via [RFC3986] URI patterns. |
+--------------------+----------------------------------------+
| uri-regex-match | Allowing the specification of trigger |
| | targets via regexes matching their |
| | URI, as defined in Section 4.1.2.6. |
+--------------------+----------------------------------------+
| content-objectlist | Allowing the specification of trigger |
| | targets via an object list and an |
| | object list type. |
+--------------------+----------------------------------------+
Table 3
Each trigger usually refers to the targets by the target URLs, using
a "urls" trigger spec object or some aggregating spec such as the
"url-regex-match". If content URLs are transformed by an
intermediate CDN in a cascade, that intermediate CDN MUST similarly
transform URLs in triggers it passes to its dCDNs.
When processing a trigger, CDNs MUST ignore the URL scheme (HTTP or
HTTPS) in comparing URLs. For example, for a CI/T "invalidate" or
"purge" action, content MUST be invalidated or purged regardless of
the protocol clients used to request it.
4.1.2.1. Generic Spec Object
A trigger resource, as defined in Section 4.1, includes an array of
trigger spec objects. Each trigger spec object contains properties
that are used as trigger target selection directives for dCDN when
processing the trigger. e.g. content URLs or metadata URI patterns.
Each such trigger spec is a specialization of a CDNI
GenericTriggerSpec object. The GenericTriggerSpec object abstracts
the basic information required for trigger distribution from the
specifics of any given property (i.e., property semantics,
enforcement options, etc.).
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The semantics of the trigger specs list is additive, i.e., the
trigger applies to any object matching one of the listed specs.
A GenericSpecObject object is a wrapper for managing individual CDNI
Trigger specs in an opaque manner.
It is encoded as a JSON object containing the following name/value
pairs:
Name: trigger-subject
Description: Case-insensitive CDNI Trigger subject.
Value: String containing the type of the subject matching the
generic-trigger-spec-value property, such as "content" or
"metadata" as defined in Section 4.1.2.2.
Mandatory: Yes.
Name: generic-trigger-spec-type
Description: Case-insensitive CDNI Trigger spec type.
Value: String containing the spec type of the object contained
in the generic-trigger-spec-value property (see table in
Section 4.1.2).
Mandatory: Yes.
Name: generic-trigger-spec-value
Description: A CDNI Trigger spec object.
Value: Defined by the value of the generic-trigger-spec-type
property.
Mandatory: Yes.
The structure of a JSON-serialized GenericTriggerSpec object,
containing a specific trigger spec is illustrated below:
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{
"generic-trigger-spec-type":
<Type of this trigger spec>,
"generic-trigger-spec-value":
{
<properties of this trigger spec object>
},
"generic-trigger-spec-subject":
<Category of this trigger spec subject>
}
4.1.2.2. Trigger Subject
Because the scope of the trigger may relate to either metadata as
well as content, the "trigger spec object" also specifies the
trigger's target subject (i.e., metadata or content) against which to
match.
All trigger subjects MUST be registered in the IANA "CDNI CI/T
Trigger Subjects" registry (see Section 7.4).
dCDN receiving a trigger creation request containing a trigger
subject that it does not recognize or does not support MUST reject
the request by creating a trigger resource with "failed" state and
the "errors" array containing an Error.v2 Description with error
"esubject" (see Section 4.1.5.2).
This document also defines an initial set of trigger subject values
and registers them in the IANA "CDNI CI/T Trigger Subjects" registry:
+=============+====================================================+
| JSON String | Description |
+=============+====================================================+
| metadata | Indicating the trigger target specification refers |
| | to Metadata object(s), as defined at [RFC8006]. |
+-------------+----------------------------------------------------+
| content | Indicating the trigger target specification refers |
| | to client-facing content objects. |
+-------------+----------------------------------------------------+
Table 4
4.1.2.3. URLs Spec
The "urls" spec type allows uCDN to manage uCDN content or metadata
objects held by dCDN based on the objects' URLs.
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The URLs spec is encoded as a JSON object containing the following
name/value pairs:
Name: urls
Description: An array of URLs over which the trigger MUST be
executed.
Value: A JSON array of URLs represented as JSON strings.
Mandatory: Yes.
Name: url-type
Description: Type of URL used.
Value: URL Type as defined in Section 4.3.1.
Mandatory: No. When omitted or empty, "published" URL type is
assumed.
Below is an example of a JSON-serialized URLs spec object, matching
the metadata at metadata.example.com/a/b/c.
{
"trigger-subject": "metadata",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [ "https://metadata.example.com/a/b/c" ],
"url-type": "published"
}
}
4.1.2.4. CCIDs Spec
The "ccids" spec type allows uCDN to specify the Content Collection
IDentifier (CCID) of content to which the trigger applies. The CCID
is a grouping of content as defined by [RFC8006]. The "ccids" spec
type is valid only for the content spec subject (see
Section 4.1.2.2).
CCIDs spec is encoded as a JSON object containing the following name/
value pairs:
Name: ccids
Description: An array of Content Collection IDentifiers over
which the trigger MUST be executed.
Value: A JSON array of strings, where each string is a Content
Collection IDentifier.
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Mandatory: Yes.
4.1.2.5. URI Pattern Match Spec
The "uri-pattern-match" spec type allows uCDN to manage uCDN content
or metadata objects held by dCDN based on the objects' URI pattern.
The value is a UriPatternMatch object, as defined in
Section 4.1.2.5.1.
4.1.2.5.1. UriPatternMatch
A UriPatternMatch consists of a string pattern to match against a
URI, and flags describing the type of match.
It is encoded as a JSON object containing the following name/value
pairs:
Name: pattern
Description: A pattern for URI matching.
Value: A JSON string representing the pattern. The pattern can
contain the wildcards "*" and "?", where "*" matches any
sequence of [RFC3986] pchar or "/" characters (including the
empty string) and "?" matches exactly one [RFC3986] pchar
character. The three literals "$", "*" and "?" MUST be
escaped as "$$", "$*" and "$?" (where "$" is the designated
escape character). All other characters are treated as
literals.
Mandatory: Yes.
Name: case-sensitive
Description: Flag indicating whether or not case-sensitive
matching should be used.
Value: One of the JSON values "true" (the matching is case
sensitive) or "false" (the matching is case insensitive).
Mandatory: No; default is "false", i.e., a case-insensitive
match.
Name: match-query-string
Description: Flag indicating whether to include the query part
of the URI when compared against the pattern.
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Value: One of the JSON values "true" (the full URI, including
the query part, should be compared against the given pattern)
or "false" (the query part of the URI should be dropped before
comparison with the given pattern).
Mandatory: No; default is "false". The query part of the URI
should be dropped before comparison with the given pattern.
Name: url-type
Description: Type of URLs to match.
Value: URL Type as defined in Section 4.3.1.
Mandatory: No. When omitted or empty, "published" URL type is
assumed.
Example of case-sensitive prefix match against
"https://www.example.com/trailers/":
{
"pattern": "https://www.example.com/trailers/*",
"case-sensitive": true
}
4.1.2.6. URI Regex Match Spec
The "uri-regex-match" spec type allows uCDN to manage content or
metadata objects held by dCDN based on the objects' URI regex.
4.1.2.6.1. RegexMatch
A RegexMatch consists of a regular expression string a URI is matched
against, and flags describing the type of match. It is encoded as a
JSON object with the following properties:
Name: regex
Description: A regular expression for URI matching.
Value: A regular expression to match against the URI, i.e.,
against the path-absolute and the query string parameters
[RFC3986]. The regular expression string MUST be compatible
with POSIX [POSIX.1] Section 9 Extended Regular Expressions.
This regular expression MUST be evaluated in the POSIX locale
(POSIX [POSIX.1] Section 7.2).
Note: Because '\' has a special meaning in JSON [RFC8259] as
the escape character within JSON strings, the regular
expression character '\' MUST be escaped as '\\'.
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Mandatory: Yes.
Name: case-sensitive
Description: Flag indicating whether or not case-sensitive
matching should be used.
Value: JSON boolean. Either "true" (the matching is case-
sensitive) or "false" (the matching is case insensitive).
Mandatory: No; default is "false", i.e., a case-insensitive
match.
Name: match-query-string
Description: Flag indicating whether to include the query part
of the URI when compared against the regex.
Value: JSON Boolean. Either "true" (the full URI, including
the query part, should be compared against the regex) or
"false" (the query part of the URI should be dropped before
comparison with the given regex).
Mandatory: No; default is "false". The query part of the URI
MUST be dropped before comparison with the given regex. This
makes the regular expression simpler and safer for cases in
which the query parameters are not relevant for the match.
Name: url-type
Description: Type of URLs to match against.
Value: URL Type as defined in Section 4.3.1.
Mandatory: No. When omitted or empty, "published" URL type is
assumed.
Example of a case-sensitive, no query parameters, regex match against
is below.
Please note that some lines in the example are wrapped for clarity.
"^(https:\/\/video\.example\.com)\/([a-z])\/
movie1\/([1-7])\/*(index.m3u8|\d{3}.ts)$"
{
"regex": "^(https:\\/\\/video\\.example\\.com)\\/([a-z])\\/
movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
"case-sensitive": true,
"match-query-string": false
}
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This regex matches URLs of the domain "video.example.com" where the
path structure is /(single lower case letter)/(name-of-title)/(single
digit between 1 to 7)/(index.m3u8 or a 3 digit number with ts
extension). For example:
https://video.example.com/d/movie1/5/index.m3u8
or
https://video.example.com/k/movie1/4/013.ts
4.1.2.7. Object List Spec
The "objectlist" spec type allows uCDN to manage content held by dCDN
based on structured object lists. The Object List spec type is valid
only for the content spec subject (see Section 4.1.2.2).
An object list is encoded as a JSON object with the following
properties:
Name: objects
Description: An array of objects to be used in the trigger
Value: ObjectList (Section 4.3.2) object
Mandatory: Yes.
4.1.3. Trigger Extensions
A "trigger" object, as defined in Section 4.1 includes an optional
array of trigger extension objects. A trigger extension contains
properties that are used as directives for dCDN when executing the
trigger command, e.g., location policies, time policies, and so on.
Each such CDNI Trigger extension is a specialization of a CDNI
GenericTriggerExtension object. The GenericTriggerExtension object
abstracts the basic information required for trigger distribution
from the specifics of any given property (i.e., property semantics,
enforcement options, etc.). All trigger extensions are optional, and
it is thus the responsibility of the extension specification to
define a consistent default behavior for extensions supported by dCDN
when not specified by uCDN.
4.1.3.1. Enforcement Options
The trigger enforcement options concept is in accordance with the
metadata enforcement options as defined in Section 3.2 of [RFC8006].
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The GenericTriggerExtension object defines the properties contained
within it as well as whether or not the properties are "mandatory-to-
enforce". If dCDN does not understand or support a mandatory-to-
enforce property, dCDN MUST NOT execute the trigger command. If the
extension is not mandatory-to-enforce, then that
GenericTriggerExtension object can be safely ignored and the trigger
command can be processed in accordance with the rest of the CDNI
Trigger spec.
Although a CDN MUST NOT execute a trigger command if a mandatory-to-
enforce extension cannot be enforced, it could still be safe to
redistribute that trigger (the "safe-to-redistribute" property) to
another CDN without modification. For example, in the cascaded CDN
case, a transit CDN (tCDN) could convey mandatory-to-enforce trigger
extension to dCDN. For a trigger extension that does not require
customization or translation (i.e., trigger extension that is safe-
to-redistribute), the data representation received off the wire MAY
be stored and redistributed without being understood or supported by
tCDN. However, for trigger extension that requires translation,
transparent redistribution of uCDN trigger values might not be
appropriate. Certain trigger extensions can be safely, though
perhaps not optimally, redistributed unmodified. For example,
preposition command might be executed in suboptimal times for some
geographies if transparently redistributed, but it might still work.
Redistribution safety MUST be specified for each
GenericTriggerExtension listed. If a CDN does not understand or
support a given GenericTriggerExtension object that is not safe-to-
redistribute, the CDN MUST set the "incomprehensible" flag to true
for that GenericTriggerExtension object before redistributing it.
The "incomprehensible" flag signals to dCDN that trigger metadata was
not properly transformed by the tCDN. A CDN MUST NOT attempt to
execute a trigger with an extension that has been marked as
"incomprehensible" by uCDN.
tCDNs MUST NOT change the value of mandatory-to-enforce or safe-to-
redistribute when propagating a trigger to dCDN. Although a tCDN can
set the value of "incomprehensible" to true, a tCDN MUST NOT change
the value of "incomprehensible" from true to false.
Table 5 describes the action to be taken by a tCDN for the different
combinations of mandatory-to-enforce ("MtE") and safe-to-redistribute
("StR") properties when the tCDN either does or does not understand
the trigger extension object in question:
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+=======+=======+============+=================================+
| MtE | StR | Extension | Trigger action |
| | | object | |
| | | understood | |
| | | by tCDN | |
+=======+=======+============+=================================+
| False | True | True | Can execute and redistribute. |
+-------+-------+------------+---------------------------------+
| False | True | False | Can execute and redistribute. |
+-------+-------+------------+---------------------------------+
| False | False | False | Can execute. MUST set |
| | | | "incomprehensible" to true when |
| | | | redistributing. |
+-------+-------+------------+---------------------------------+
| False | False | True | Can execute. Can redistribute |
| | | | after transforming the trigger |
| | | | extension (if the CDN knows how |
| | | | to do so safely); otherwise, |
| | | | MUST set "incomprehensible" to |
| | | | true when redistributing. |
+-------+-------+------------+---------------------------------+
| True | True | True | Can execute and redistribute. |
+-------+-------+------------+---------------------------------+
| True | True | False | MUST NOT execute but can |
| | | | redistribute. |
+-------+-------+------------+---------------------------------+
| True | False | True | Can execute. Can redistribute |
| | | | after transforming the trigger |
| | | | extension (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 |
| | | | "incomprehensible" to true when |
| | | | redistributing. |
+-------+-------+------------+---------------------------------+
Table 5: Action to be taken by a tCDN for the different
combinations of MtE and StR properties
Table 6 describes the action to be taken by dCDN for the different
combinations of mandatory-to-enforce and "incomprehensible"
("Incomp") properties, when dCDN either does or does not understand
the trigger extension object in question:
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+=======+========+==================+==========================+
| MtE | Incomp | Extension object | Trigger action |
| | | understood by | |
| | | dCDN | |
+=======+========+==================+==========================+
| False | False | True | Can execute. |
+-------+--------+------------------+--------------------------+
| False | True | True | Can execute but MUST NOT |
| | | | interpret/apply any |
| | | | trigger extension marked |
| | | | as "incomprehensible". |
+-------+--------+------------------+--------------------------+
| False | False | False | Can execute. |
+-------+--------+------------------+--------------------------+
| False | True | False | Can execute but MUST NOT |
| | | | interpret/apply any |
| | | | trigger extension marked |
| | | | as "incomprehensible". |
+-------+--------+------------------+--------------------------+
| True | False | True | Can execute. |
+-------+--------+------------------+--------------------------+
| True | True | True | MUST NOT execute. |
+-------+--------+------------------+--------------------------+
| True | False | False | MUST NOT execute. |
+-------+--------+------------------+--------------------------+
| True | True | False | MUST NOT execute. |
+-------+--------+------------------+--------------------------+
Table 6: Action to be taken by dCDN for the different
combinations of MtE and Incomp properties
4.1.3.2. GenericExtensionObject
A GenericTriggerExtension object is a wrapper for managing individual
CDNI Trigger extensions in an opaque manner.
It is encoded as a JSON object containing the following name/value
pairs:
Name: generic-trigger-extension-type
Description: Case-insensitive CDNI Trigger extension object
type.
Value: String containing the CDNI Extension Type [RFC7736] of
the object contained in the "generic-trigger-extension-value"
property (see table in Section 2.7).
Mandatory: Yes.
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Name: generic-trigger-extension-value
Description: CDNI Trigger extension object.
Value: Defined by the value of the "generic-trigger-extension-
type" property above.
Mandatory: Yes.
Name: mandatory-to-enforce
Description: Flag identifying whether or not the enforcement of
this trigger extension is mandatory.
Value: Boolean.
Mandatory: No. The default is to treat the trigger extension
as mandatory to enforce (i.e., a value of True)
Name: safe-to-redistribute
Description: Flag identifying whether or not this trigger
extension can be safely redistributed without modification,
even if the CDN fails to understand the extension.
Value: Boolean.
Mandatory: No. The default is to allow transparent
redistribution (i.e., a value of True).
Name: incomprehensible
Description: Flag identifying whether or not any CDN in the
chain of delegation has failed to understand and/or failed to
properly transform this trigger extension object. Note: This
flag only applies to trigger extension objects whose "safe-to-
redistribute" property has a value of False.
Value: Boolean.
Mandatory: No. The default is comprehensible (i.e., a value of
False).
The structure of a JSON-serialized GenericTriggerExtension object
containing a specific trigger extension object is illustrated below:
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{
"generic-trigger-extension-type":
<Type of this trigger extension object>,
"generic-trigger-extension-value":
{
<properties of this trigger extension object>
},
"mandatory-to-enforce": <bool>,
"safe-to-redistribute": <bool>,
"incomprehensible": <bool>
}
4.1.3.3. Trigger Extension Objects
The objects defined below are intended to be used in the
GenericTriggerExtension object's generic-trigger-extension-value
field as defined in Section 4.1.3.2, and their generic-trigger-
extension-type property MUST be set to the appropriate Extension Type
as defined in Section 2.7.
4.1.3.3.1. LocationPolicy Extension
A content operation may be relevant for a specific geographical
region or need to be excluded from a specific region. In this case,
the trigger should be applied only to parts of the network that are
either "included" or "not excluded" by the location policy. Note
that the restrictions here are on the cache location rather than the
client location.
The LocationPolicy object defines which CDN or cache locations for
which the trigger command is relevant.
Example use cases:
* Preposition: Certain contracts allow for prepositioning or
availability of contracts in all regions except for certain
excluded regions in the world, including caches. For example,
some content cannot ever knowingly touch servers in a specific
country, including cached content. Therefore, these regions MUST
be excluded from a prepositioning operation.
* Purge: In certain cases, content may have been located on servers
in regions where the content must not reside. In such cases, a
purge operation to remove content specifically from that region is
required.
Object specification:
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Name: locations
Description: An Access List that allows or denies (blocks) the
trigger execution per cache location.
Value: Array of LocationRule objects (see Section 4.2.2.1 of
[RFC8006]).
Mandatory: Yes.
Name: url-type
Description: Type of URL used in the ObjectList(s).
Value: URL Type as defined in Section 4.3.1.
Mandatory: No. When omitted or empty, the "published" URL type
is assumed.
If a location policy object is not listed within the trigger command,
the default behavior is to execute the trigger in all available
caches and locations of dCDN.
The trigger command is allowed, or denied, for a specific cache
location according to the action of the first location whose
footprint matches that cache's location. If two or more footprints
overlap, the first footprint that matches against the cache's
location determines the action a CDN MUST take. If the "locations"
property is an empty list or if none of the listed footprints match
the location of a specific cache location, then the result is
equivalent to a "deny" action.
The following is an example of a JSON-serialized generic trigger
extension object containing a location policy object that allows the
trigger execution in the US but blocks its execution in Canada:
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{
"generic-trigger-extension-type": "location-policy",
"generic-trigger-extension-value": {
"locations": [
{
"action": "allow",
"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}]
},
{
"action": "deny",
"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "ca" ]
}]
}
]
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true,
"incomprehensible": false
}
4.1.3.3.2. TimePolicy Extension
uCDN may wish to perform content management operations on dCDN on a
specific schedule. The TimePolicy extension allows uCDN to instruct
dCDN to execute the trigger command in a desired time window. For
example, a content provider that wishes to pre-populate a new episode
at off-peak time so that it would be ready on caches at prime time
when the episode is released for viewing. A scheduled operation
enables uCDN to direct dCDN in what time frame to execute the
trigger.
uCDN may wish to schedule a trigger such that dCDN will execute it in
local time, as it is measured in each region. For example, uCDN may
wish dCDN to pull the content at off-peak hours, between 2AM-4AM,
however, as a CDN is distributed across multiple time zones, the UTC
definition of 2AM depends on the actual location.
We define two alternatives for localized scheduling:
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* Regional schedule: When used in conjunction with the Location
Policy defined in Section 4.1.3.3.1, uCDN can trigger separate
commands for different geographical regions, for each region using
a different schedule. This allows uCDN to control the execution
time per region.
* Local Time schedule: We introduce a "local time" version for
Internet timestamps that follows the notation for local time as
defined in Section 4.2.2 of [ISO8601]. When local time is used,
that dCDN SHOULD execute the triggers at different absolute times,
according to the local time of each execution location.
Object specification:
Name: unix-time-window
Description: A UNIX epoch time window in which the trigger
SHOULD be executed.
Value: TimeWindow object using UNIX epoch timestamps (see
Section 4.2.3.2 of [RFC8006]).
Mandatory: No, but exactly one of "unixEpochWindow" or
"utcWindow" MUST be present.
Name: utc-window
Description: A UTC time window in which the trigger SHOULD be
executed.
Value: UTCWindow object as defined in Section 4.1.3.3.2.1.
Mandatory: No, but exactly one of "unixEpochWindow" or
"utcWindow" MUST be present.
If a time policy object is not listed within the trigger command, the
default behavior is to execute the trigger in a time frame most
suitable to dCDN taking under consideration other constraints and /
or obligations.
Example of a JSON-serialized generic trigger extension object
containing a time policy object that schedules the trigger execution
to a window between 09:00 01/01/2000 UTC and 17:00 01/01/2000 UTC,
using the "unix-time-window" property:
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{
"generic-trigger-extension-type": "time-policy",
"generic-trigger-extension-value":
{
"unix-time-window": {
"start": 946717200,
"end": 946746000
}
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true,
"incomprehensible": false
}
4.1.3.3.2.1. UTCWindow
A UTCWindow object describes a time range in UTC or UTC and a zone
offset that can be applied by a TimePolicy.
It is encoded as a JSON object containing the following name/value
pairs:
Name: start
Description: The start time of the window.
Value: Internet date and time as defined in [RFC3339].
Mandatory: No. but at least one of "start" or "end" MUST be
present and non-empty.
Name: end
Description: The end time of the window.
Value: Internet date and time as defined in [RFC3339].
Mandatory: No. but at least one of "start" or "end" MUST be
present and non-empty.
Example JSON-serialized UTCWindow object that describes a time window
from 02:30 01/01/2000 UTC to 04:30 01/01/2000 UTC:
{
"start": "2000-01-01T02:30:00.00Z",
"end": "2000-01-01T04:30:00.00Z"
}
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Example JSON-serialized UTCWindow object that describes a time window
in New York time zone offset UTC-05:00 from 02:30 01/01/2000 to 04:30
01/01/2000:
{
"start": "2000-01-01T02:30:00.00-05:00",
"end": "2000-01-01T04:30:00.00-05:00"
}
4.1.3.3.3. ExecutionPolicy Extension
Unless specified otherwise, dCDN is at liberty to decide how to
choose trigger commands for execution from all pending commands,
whether to process trigger commands sequentially or in parallel,
immediately upon acceptance, or with a delay in batches. uCDN may
wish to control trigger processing in more detail, including the
order of execution, dependencies, and concurrency.
Example use cases:
* Priority: uCDN may have multiple trigger commands in "pending"
and/or "active" mode. For example, trigger commands with policy
constraints, a large number of content objects affected, or other
dCDN business logic may take a long time to execute. uCDN may
wish to prescribe the order in which dCDN picks up its trigger
commands for execution from the "pending" queue, by indicating a
relative priority of each trigger. The priority would affect the
selection of trigger commands specific to the requesting uCDN.
dCDN may separately prioritize triggers from multiple uCDNs
subject to its business logic. Multiple priority-related use
cases exist:
- uCDN needs to introduce an urgent "purge" or "invalidate"
trigger into an existing queue of trigger commands to correct
wrong versions of content objects published by it
- uCDN needs to indicate which content objects should be
prepositioned, purged or invalidated first, for example
prepositioning newer released content before prepositioning
updates to an existing catalog
* Prerequisite: In some cases, uCDN may wish to indicate what
trigger commands should be processed and completed before another
trigger command is processed. For example, uCDN may want to
rectify incorrectly published content by purging content objects
and then prepositioning them again. In this case, uCDN may want
the preposition trigger command to be processed only after the
purge trigger command has been processed because concurrent
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processing of these triggers may cause the new version of these
content objects to be purged. Alternatively, uCDN may wish to
condition the execution of purge or invalidation triggers upon the
completion or cancellation of long-running preposition triggers to
avoid race conditions that would result from processing these in
parallel. The prerequisite requirement implies that a previous
trigger reaches one of the following states:
- "complete" or "processed" for successful completion
- "failed" for failed processing
- "cancelled" for completion of cancellation
* Urgency: uCDN may wish to indicate that dCDN should process a
trigger command without delay. This requirement is separate and
additional to priority, as priority indicates the order in which
triggers should be processed, yet does not prescribe how soon each
trigger should be executed. dCDN MAY reject such requests for
urgent processing using "ereject" error code. This can happen due
to dCDN internal business logic (e.g. batch-driven purge and
invalidation), or due to dependencies on other triggers that could
not be completed by dCDN immediately. In such a case uCDN should
either modify the request by removing prerequisites or cancel such
pending triggers before re-trying the request.
uCDN may combine multiple options in the same trigger command. dCDN
should consider the following when processing such commands:
* dCDN MUST reject triggers that are dependent on other pending
triggers with lower priority to prevent deadlocks.
* When introducing an urgent trigger uCDN SHOULD indicate a priority
that is equal to or higher than the highest priority among the
pending triggers that belong to the same uCDN. dCDN MUST reject
urgent triggers that have lower priority than other pending
triggers of the same uCDN.
* dCDN MUST reject an urgent trigger that has pending triggers as
its prerequisite. dCDN MAY reject an urgent trigger that has
triggers in an "active" or "cancelling" state as its prerequisite,
such as when such triggers are deemed to take a long time to
complete or cancel.
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When combining ExtensionPolicy with Section 4.1.3.3.2, TimePolicy
governs the time window when the trigger can execute, while
ExecutionPolicy controls the order of trigger execution within their
respective windows. The following error conditions should be
considered by dCDN:
* When a trigger is marked urgent, but its TimePolicy extension
doesn't allow immediate processing, it should be rejected by dCDN.
* When a trigger has a TimePolicy extension and is also dependent on
another trigger with a TimePolicy extension, that specifies an
execution window (directly or via a chain of dependency) that
doesn't start until after the depending trigger's execution window
ends, such a trigger should be rejected.
The ExtensionPolicy extension is encoded as a JSON object containing
the following name/value pairs:
Name: priority
Description: Relative weight of the trigger. When picking a
trigger for execution from all pending triggers posted by each
uCDN, dCDN MUST choose the trigger with the highest priority
first.
Value: Integer from -100 to 100.
Mandatory: No. The value defaults to zero if omitted.
Name: depends
Description: Links to trigger resources that the current
trigger depends on. Indicates which triggers should fully
finish processing before starting execution of the current
trigger. The triggers need to be in one of the following
states to be considered finished: "complete", "processed",
"failed" or "cancelled".
Value: A JSON array of zero or more URLs, represented as JSON
strings.
Mandatory: No. In case of a missing or an empty list, no
dependencies are assumed.
Name: urgent
Description: Indicates whether the trigger should be
immediately moved to the "active" state upon acceptance. In
the absence of this flag, dCDN is at liberty to choose the time
for trigger execution, e.g., batch processing.
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Value: Boolean.
Mandatory: No. The default is to handle the trigger as not
urgent.
The following is an example of a JSON-serialized generic extension
trigger object containing an execution policy object that specifies
trigger priority of 100, marks the trigger as urgent and makes its
execution dependent on the completion of the previously created
triggers :
{
"generic-trigger-extension-type": "execution-policy",
"generic-trigger-extension-value":
{
"priority": 100,
"depends": [
"https://dcdn.example.com/triggers/100",
"https://dcdn.example.com/triggers/101"
],
"urgent": true
}
}
4.1.4. Trigger State
Trigger state describes the current state of the triggered activity.
It MUST be one of the JSON strings in the following table:
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+============+==============================================+
| JSON | Description |
| String | |
+============+==============================================+
| pending | The trigger has not yet been acted upon. |
+------------+----------------------------------------------+
| active | The trigger is currently being acted upon. |
+------------+----------------------------------------------+
| complete | The trigger processing completed |
| | successfully. |
+------------+----------------------------------------------+
| processed | The trigger has been created, and no further |
| | status update will be made (can be used in |
| | cases where completion cannot be confirmed). |
+------------+----------------------------------------------+
| failed | The trigger processing could not be |
| | completed. |
+------------+----------------------------------------------+
| cancelling | The trigger processing is still in progress, |
| | but the trigger has been cancelled by uCDN. |
+------------+----------------------------------------------+
| cancelled | The trigger was cancelled by uCDN. |
+------------+----------------------------------------------+
Table 7
Along with the trigger state, the Trigger resource has a state reason
property, allowing dCDN to provide additional information for the
trigger state. For example, dCDN may indicate that the trigger state
is "pending" due to one of the execution prerequisites not being
fulfilled. Such a prerequisite may be specified via one of the
extensions.
4.1.5. Trigger Errors
4.1.5.1. Error.v2 Description
An Error.v2 Description is used to report the failure of a trigger.
It is encoded as a JSON object with the following name/value pairs:
Name: error
Value: Error Code, as defined in Section 4.1.5.2.
Mandatory: Yes.
Name: description
Description: A human-readable description of the error.
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Value: A JSON string, the human-readable description.
Mandatory: No.
Name: specs
Description: Array of trigger spec objects from the
corresponding "specs" array at the Trigger Specification. Only
those specs to which the error applies are listed.
Value: Array of Trigger Specifications, as defined in
Section 4.1, where each spec object MUST be exactly as they
appear in the request.
Mandatory: Yes.
Name: extensions
Description: Array of trigger extension objects copied from the
corresponding "extensions" array from the Trigger
Specification. Only those extensions to which the error
applies are included, but those extensions MUST be exactly as
they appear in the request.
Value: Array of GenericTriggerExtension objects, where each
extension object is copied from the "extensions" array values
in the Trigger Specification.
Mandatory: No. The "extensions" array SHOULD be used only if
the error relates to extension objects. Property omission
should be interpreted as "the error is not related to any
extension".
Name: cdn-id
Description: The CDN PID of the CDN where the error occurred.
The "cdn-id" property is used by the originating uCDN or by the
propagating dCDN in order to distinguish in which CDN the error
occurred.
Value: A non-empty JSON string, where the string is a CDN PID
as defined in Section 3.7
Mandatory: Yes. dCDN may use its own CDN PID if it does not
want to expose the CDN PIDs of dCDNs.
Name: objects
Description: List of objects that failed to be processed during
trigger execution.
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Value: An array of ObjectList (Section 4.3.2) objects. dCDN
SHOULD provide the list of objects that it failed to process
during trigger execution with Section 4.1.2.7, provided that
dCDN advertised support for extended status (Section 5.5).
Mandatory: No. An empty array is allowed and is equivalent to
omitting "objects" from the Error.v2 Description.
Example of a JSON-serialized Error.v2 Description object reporting a
malformed object list :
{
"error": "econtent",
"description": "Failed to parse HLS object list",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "content-objectlist",
"generic-trigger-spec-value": {
"objects": [{
"href": "https://www.example.com/hls/title/index.m3u8",
"type": "hls"
}]
}}
],
"objects": [{
"href": "https://www.example.com/hls/title/index.m3u8",
"type": "hls"
}],
"cdn": "AS64500:0"
}
Example of a JSON-serialized Error.v2 Description object reporting an
unsupported extension object:
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{
"errors": [{
"error": "eextension",
"description": "unrecognized extension <type>",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [
"https://www.example.com/a/b/c/1",
"https://www.example.com/a/b/c/2"
]
}
}],
"extensions": [{
"generic-trigger-extension-type": "location-policy",
"generic-trigger-extension-value": {
"locations": [{
"action": "deny",
"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "ca" ]
}]
}]
}
}],
"cdn": "AS64500:0"
}]
}
4.1.5.2. Error Code
This type is used by dCDN to report failures in trigger processing.
All Error Codes MUST be registered in the IANA "CDNI CI/T Error
Codes" registry (see Section 7.7). Unknown Error Codes MUST be
treated as fatal errors, and the request MUST NOT be automatically
retried without modification.
The following Error Codes are defined by this document and MUST be
supported by an implementation of the CI/T v2 interface.
+==============+================================+==============+
| Error Code | Description | Registration |
+==============+================================+==============+
| emeta | dCDN was unable to acquire | RFCthis |
| | and/or is not in possession of | |
| | metadata required to fulfill | |
| | the request. | |
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+--------------+--------------------------------+--------------+
| econtent | dCDN was unable to acquire | RFCthis |
| | content (CI/T "preposition" | |
| | commands only). | |
+--------------+--------------------------------+--------------+
| eperm | uCDN does not have permission | RFCthis |
| | to create the trigger as | |
| | requested(for example, the | |
| | data is owned by another CDN). | |
+--------------+--------------------------------+--------------+
| ereject | dCDN is not willing to process | RFCthis |
| | the trigger (for example, a | |
| | "preposition" request for | |
| | content at a time when dCDN | |
| | would not accept Request | |
| | Routing requests from uCDN). | |
+--------------+--------------------------------+--------------+
| ecdn | An internal error in dCDN or | RFCthis |
| | one of its dCDNs. | |
+--------------+--------------------------------+--------------+
| ecancelled | uCDN cancelled the request. | RFCthis |
+--------------+--------------------------------+--------------+
| eunsupported | The Trigger Specification | RFCthis |
| | contained an "action type" | |
| | that is not supported by dCDN. | |
| | No action was taken by dCDN | |
| | other than to create a trigger | |
| | in a "failed" state. | |
+--------------+--------------------------------+--------------+
| espec | An error occurred while | RFCthis |
| | parsing a generic trigger | |
| | spec, or that the specific | |
| | trigger spec is not supported | |
| | by the CDN. | |
+--------------+--------------------------------+--------------+
| esubject | An error occurred while | RFCthis |
| | parsing a trigger subject, or | |
| | that the specific trigger | |
| | subject is not supported by | |
| | the CDN. | |
+--------------+--------------------------------+--------------+
| eextension | An error occurred while | RFCthis |
| | parsing a generic trigger | |
| | extension, or that the | |
| | specific extension is not | |
| | supported by the CDN. | |
+--------------+--------------------------------+--------------+
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Table 8
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
4.2. Trigger Collection Resource
As described in Section 2, trigger resources exist in dCDN to
represent a specific activity that uCDN requests dCDN to carry out.
A collection of trigger resources is a resource that represents all
triggers in it. By default trigger resources in a collection are
represented using their unique URIs. Note that the collection may
refer to CI/T Resources from several versions of CI/T objects, i.e.,
a subsequent call for the retrieval of the relevant trigger status
may provide objects of various MIME media types: ci-trigger-status as
defined in [RFC8007], ci-trigger.v2 defined in this document, or
objects of future CI/T objects versions, based on the version of the
JSON object used to create the trigger.
dCDN MUST make a collection of uCDN's trigger resources available to
that uCDN. This collection includes all triggers that have been
created by uCDN and have not yet been deleted by uCDN (see
Section 3.5) or expired and removed by dCDN (see Section 3.6).
Trigger resources belonging to uCDN MUST NOT be visible to any other
CDN. dCDN could, for example, achieve this by offering different
collection URLs to each uCDN and by filtering the response based on
uCDN with which the HTTP client is associated.
To trigger an activity in dCDN or to cancel a triggered activity, the
uCDN POSTs a trigger representation to dCDN's collection of uCDN's
triggers.
To allow uCDN to check the status of multiple triggers in a single
request, dCDN MAY maintain optional representations of the trigger
collection, that contain a subset of all triggers, filtered based on
a parameter These filtered collection representations are "optional-
to-implement", but if they are implemented, dCDN MUST include links
to them in the trigger collection.
dCDN MAY provide filtered collections per trigger state
(Section 4.1.4). If implemented, dCDN SHOULD provide a separate
filtered collection for every trigger state, and advertise these
collections in the trigger collection.
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dCDN MAY provide filtered collections per trigger label, as specified
by uCDN when creating a trigger resource (Section 4.1). If
implemented, dCDN SHOULD provide a separate filtered collection for
every unique trigger label, and advertise these collections in the
collection of all Trigger resources.
Trigger Collections MUST use a MIME media type of "application/cdni;
ptype=ci-trigger-collection".
A Trigger Collection is encoded as a JSON object containing the
following name/value pairs:
Name: triggers
Description: Links to triggers in the collection.
Value: A JSON array of zero or more URLs, represented as JSON
strings.
Mandatory: Yes.
Name: staleresourcetime
Description: The length of time for which dCDN guarantees to
keep a completed trigger resource. After this time, dCDN
SHOULD delete the trigger resource and all references to it
from the collection.
Value: A JSON number, which must be a positive integer,
representing time in seconds.
Mandatory: Yes, in the collection of all triggers if dCDN
deletes stale entries. If the property is present in the
filtered collection representation, it MUST have the same value
as in the collection of all triggers.
Name: coll-state
Description: Array of all Section 4.2.2 objects.
Value: An array of JSON-encoded FilteredCollectionStatusLink
objects.
Mandatory: Mandatory in the collection of all triggers, if dCDN
implements the filtered collections. Otherwise, optional.
Name: coll-label
Description: Array of all Section 4.2.1 objects.
Value: An array of JSON-encoded FilteredCollectionLabelLink
objects.
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Mandatory: Mandatory in the collection of all triggers, if dCDN
implements the filtered collections. Otherwise, optional.
Name: all-triggers
Description: Array of all triggers in the collection. Should
be returned only when an extended trigger collection view is
requested as described in Section 3.4.1.1.
Value: An array of JSON-encoded triggers.
Mandatory: No. The "all-triggers" SHOULD only be used by dCDN
that supports and advertises the appropriate extended status
for trigger collections (see Section 5.5 for details).
Name: cdn-id
Description: The CDN PID of dCDN.
Value: A JSON string, dCDN's CDN PID, as defined in
Section 3.7.
Mandatory: Only in the collection of all triggers, if dCDN
implements the filtered collections. Optional in the filtered
collections (uCDN can always find dCDN's cdn-id in the
collection of all triggers, but dCDN can choose to repeat that
information in its implementation of filtered collections).
4.2.1. Filtered Collections by Status Link
The Filtered Collections by state Link object represents a link to a
filtered collection per trigger state (Section 4.1.4). It is encoded
as a JSON object containing the following name/value pairs:
Name: status
Description: Trigger state matching the filtered collection.
Value: A trigger State, as defined in Section 4.1.4.
Mandatory: Yes.
Name: collection
Description: Filtered collection URL corresponding to the
state.
Value: A URL represented as a JSON string.
Mandatory: Yes.
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4.2.2. Filtered Collections by Label Link
The Filtered Collections by Label Link object represents a link to a
filtered collection per trigger label. It is encoded as a JSON
object containing the following name/value pairs:
Name: label
Description: Trigger Label matching the filtered collection.
Value: A Trigger Label, as defined in Section 4.1.
Mandatory: Yes.
Name: collection
Description: Filtered collection URL corresponding to the
label.
Value: A URL represented as a JSON string.
Mandatory: Yes.
4.3. Other CI/T Objects
This section describes common CI/T objects and their encodings.
4.3.1. URL Type
This type is used by uCDN to indicate how to interpret URLs
referenced by trigger specs that use URLs, such as Section 4.1.2.3,
Section 4.1.2.5, Section 4.1.2.6 and Section 4.1.2.7.
One option for uCDN to use in triggers is published URLs, which are
used by end users. When using this URL type, uCDN MUST provide
configuration metadata objects related to these URLs before creating
a trigger option referencing these URLs. When this is not the case,
dCDN MUST return the error code "emeta".
When processing published URLs in "preposition" Trigger Action, dCDN
MUST invoke processing of metadata objects it would have invoked in
content acquisition to satisfy an end-user request, e.g.
SourceMetadata (see Section 4.2.1 of [RFC8006]).
Another type of URL in common use is a private URL, which is based on
cache keys that are dynamically constructed via lightweight
processing of various properties of the HTTP request and/or response.
As an example, an origin might specify a cache key as a value
returned in a specific HTTP response header.
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As an example, uCDN may prefer to use such private URLs in "purge" or
"invalidate" Trigger Actions to simplify processing.
dCDNs implementing the CI/T Interface MUST support the "published"
URL type. dCDN MAY support the additional "private" URL type. In
this case, dCDN SHOULD advertise the private URL type support via FCI
using Section 5.4. If the private URL is not supported by dCDN, it
SHOULD reject the trigger creation request using "eunsupported" Error
Code. If both URL types are supported by dCDN, uCDN MUST use only
one URL type in each trigger.
The following URL types are defined by this document and MUST be
supported by the implementation of the CI/T interface:
+===========+==================================+==============+
| URL Type | Description | Registration |
+===========+==================================+==============+
| published | Published URL used by end users | RFCthis |
| | to access content | |
+-----------+----------------------------------+--------------+
| private | Private URLs used by dCDN to | RFCthis |
| | look up content objects in cache | |
+-----------+----------------------------------+--------------+
Table 9
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
4.3.2. ObjectList
ObjectList is a metadata object describing lists of objects that can
be used in the context of CI/T v2 trigger spec, trigger status
resources and other contexts as required. The ObjectList object can
either embed the lists of objects or point to external URL(s) that
hold such lists. ObjectList allows the specification of an object
list type, providing instructions on the interpretation of the object
list format.
ObjectLists MAY be recursive, i.e. including references to secondary
manifests, including references to HLS, MPEG-DASH or MSS manifests as
well as additional JSON-encoded ObjectLists, etc. The party
consuming the object list MUST parse all recursions based on the
object list type property. When doing so, the consuming party should
also detect potential loops when the descendant ObjectList points
back to the parent ObjectList.
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In the case of uCDN accessing ObjectList objects referencing external
URLs published by dCDN, both parties should comply with the CI/T
interface security requirements (see Section 8.1 for details). When
dCDN accesses external URLs referenced by ObjectLists supplied by
uCDN, for example as part of Trigger Spec, dCDN MUST match these URLs
with source metadata objects, published by uCDN, such as
SourceMetadata objects specified in Section 4.2.1 of [RFC8006], and
use these metadata objects for content acquisition if a match was
found.
ObjectLists MAY combine regular objects and secondary ObjectLists in
the same object. Please note that when embedding non-JSON object
lists directly in ObjectList, absolute URLs MUST be provided at all
times and the text SHOULD be encoded in accordance with the JSON
grammar specification [ECMA404], including explicit newline encoding.
When uCDN accesses ObjectList metadata resources published by uCDN,
the same interface authentication and authorization requirements
would apply, as when accessing the interface itself.
ObjectList is encoded as an array of per-object records in JSON
format as follows:
External HLS manifest:
[
{
"href": "https://example.com/hls/a36f764e/index.m3u8",
"type": "hls"
}
]
External object list in text format:
[
{
"href": "https://example.com/hls/35cdc008/assets",
"type": "text"
}
]
List of external manifests and objects of mixed types:
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[
{
"href": "https://example.com/hls/35cdc008/index.m3u8",
"type": "hls"
},
{
"href": "https://example.com/dash/35cdc008/main.mpd",
"type": "dash"
},
{
"href": "https://example.com/dash/35cdc008/files.json",
"type": "json"
}
]
Embedded JSON-encoded object list:
[
{
"data": [
{
"href": "https://example.com/hls/35cdc008/index.m3u8",
"type": "hls"
},
{
"href": "https://example.com/dash/35cdc008/main.mpd",
"type": "dash"
},
{
"href": "https://example.com/img/35cdc008/thumb-l.jpg",
"size": 10260
},
{
"href": "https://example.com/img/35cdc008/thumb-s.jpg",
"size": 1453
}
],
"type": "json"
}
]
Embedded HLS manifest:
Please note that some lines in the example are wrapped for clarity.
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[
{
"data": "#EXTM3U\n
#EXT-X-STREAM-INF:BANDWIDTH=150000,RESOLUTION=416x234,
CODECS=\"avc1.42e00a,mp4a.40.2\"\n
http://example.com/low/index.m3u8\n
#EXT-X-STREAM-INF:BANDWIDTH=240000,RESOLUTION=416x234,
CODECS=\"avc1.42e00a,mp4a.40.2\"\n
http://example.com/lo_mid/index.m3u8\n
#EXT-X-STREAM-INF:BANDWIDTH=440000,RESOLUTION=416x234,
CODECS=\"avc1.42e00a,mp4a.40.2\"\n
http://example.com/hi_mid/index.m3u8\n
#EXT-X-STREAM-INF:BANDWIDTH=640000,RESOLUTION=640x360,
CODECS=\"avc1.42e00a,mp4a.40.2\"\n
http://example.com/high/index.m3u8\n
#EXT-X-STREAM-INF:BANDWIDTH=64000,
CODECS=\"mp4a.40.5\"\n
http://example.com/high/index.m3u8\n",
"type": "hls"
}
]
The ObjectList properties are as follows:
Name: data
Description: List of objects in one of the recognized formats.
Value: JSON String.
Mandatory: No. Either "data" or "href" MUST be set.
Name: href
Description: URL pointing to an external object list or object
in one of the recognized formats.
Value: A URL represented as a JSON String
Mandatory: No. Either "data" or "href" MUST be set.
Name: type
Description: Object list type to be used when parsing and
interpreting this object list. By default, each record in the
list is assumed to represent an object that does not require
additional processing.
Value: ObjectListType (see Section 4.3.2).
Mandatory: Yes.
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4.3.2.1. ObjectList Type
ObjectListType objects are used to specify the registered type of
ObjectList objects (see Section 7.5), used in trigger spec, trigger
objects and Error.v2 Description objects.
The following table defines the initial ObjectListType JSON string
values
+========+==================+===============+===============+
| JSON | Description | Specification | Protocol |
| string | | | Specification |
+========+==================+===============+===============+
| hls | HTTP Live | RFCthis | RFC 8216 |
| | Streaming | | [RFC8216] |
+--------+------------------+---------------+---------------+
| mss | Microsoft Smooth | RFCthis | MSS [MSS] |
| | Streaming | | |
+--------+------------------+---------------+---------------+
| dash | Dynamic Adaptive | RFCthis | MPEG-DASH |
| | Streaming over | | [MPEG-DASH] |
| | HTTP (MPEG-DASH) | | |
+--------+------------------+---------------+---------------+
| json | JSON-serialized | RFCthis | JSON (Section |
| | object list | | 4.3.2.2) |
+--------+------------------+---------------+---------------+
| text | Object list in | RFCthis | Text (Section |
| | text format | | 4.3.2.3) |
+--------+------------------+---------------+---------------+
Table 10
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
4.3.2.2. JSON Serialized Object List
This ObjectList type specifies a collection of objects encoded in
JSON format, where each entry is encoded as an ObjectEntry
(Section 4.3.2.4) object. The entries in the JSON object list MAY
have an object list type specified, allowing for a recursive object
list structure.
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4.3.2.3. Text Object List
Unlike the JSON Serialized Object List (Section 4.3.2.2), the text-
based object list will not support a recursive object list structure
and every object specified in it SHOULD be downloaded without
additional processing.
4.3.2.4. ObjectEntry
ObjectEntry is a metadata object describing an object and its
associated metadata, to be used in JSON-encoded ObjectList
(Section 4.3.2) objects.
The following is an example of JSON-serialized ObjectEntry objects:
[
{
"href": "https://example.com/hls/35cdc008/index.m3u8",
"type": "hls"
},
{
"href": "https://example.com/dash/35cdc008/main.mpd",
"type": "dash"
},
{
"href": "https://example.com/img/35cdc008/thumb-l.jpg",
"size": 102600
},
{
"href": "https://example.com/img/35cdc008/thumb-s.jpg",
"size": 14535
}
]
The ObjectEntry properties are as follows:
Name: href
Description: Object URL
Value: A URL represented as a JSON string.
Mandatory: Yes.
Name: type
Description: ObjectList type to be used when processing this
object. By default, ObjectEntry object is assumed to represent
an object and does not require additional processing.
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Value: ObjectListType (see Section 4.3.2.1).
Mandatory: No.
Name: size
Description: Object size, in bytes. Can be used to decide to
download the object based on size. For example, dCDN may
ignore objects that are too small or too large.
Value: Integer.
Mandatory: No.
4.3.3. CDN Provider ID
The CDN PID consists of the two characters "AS" followed by the CDN
provider's Autonomous System number [RFC1930], then a colon (":") and
an additional qualifier that is used to guarantee uniqueness in case
a particular AS has multiple independent CDNs deployed -- for
example, "AS64496:0".
If the CDN provider has multiple ASes, the same AS number SHOULD be
used in all messages from that CDN provider, unless there are
multiple distinct CDNs.
If the CDNI Request Routing Redirection interface (RI) described in
[RFC7975] is implemented by dCDN, the CI/T interface and the RI
SHOULD use the same CDN PID.
5. Footprint and Capabilities
This section covers the FCI objects required for the advertisement of
the specs, extensions, and properties introduced in this document.
5.1. CI/T Endpoint Capability Object
The CI/T trigger endpoint capability object is used to advertise one
or more CI/T interface endpoints along with CI/T interface versions
supported by these endpoints. The capability type is
"FCI.CITEndpoints". Version 1, as originally defined in [RFC8007],
is the default if this capability is not explicitly declared.
A CI/T Endpoints capability object is encoded as an array of JSON
objects containing the following name/value pairs:
Name: trigger-endpoint-uri
Description: CI/T endpoint URI
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Value: A URL represented as a JSON string.
Mandatory: Yes.
Name: trigger-versions
Description: A list of CI/T versions supported by the trigger
endpoint.
Value: An array of JSON strings.
Mandatory: Yes.
Name: trigger-subject
Description: Array of trigger subjects supported by the trigger
endpoint.
Value: An array of Strings containing the type of the subject
matching the generic-trigger-spec-value property, such as
"content" or "metadata" as defined in Section 4.1.2.2.
Mandatory: No. A missing or empty "trigger-subject" list means
that all trigger subjects are supported by the endpoint. dCDN
SHOULD advertise only one endpoint for every trigger subject
and CI/T interface version pair. If more than one interface
endpoint supports the same trigger subject and CI/T interface
version (e.g. CI/T version 2 interface for content objects),
uCDN SHOULD be able to use any of the advertised CI/T interface
endpoints interchangeably.
5.1.1. CI/T Endpoints Capability Object Serialization
The following shows an example of CI/T Endpoints Capability object
serialization for dCDN that supports versions 2 and 2.1 of the CI/T
interface.
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{
"capabilities": [
{
"capability-type": "FCI.CITEndpoints",
"capability-value": {
"trigger-endpoint-uri":
"https://dcdn.example.com/configuration/",
"trigger-versions": [ "1" ],
"trigger-subjects": "metadata"
},
"footprints": {
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}
},
{
"capability-type": "FCI.CITEndpoints",
"capability-value": {
"trigger-endpoint-uri":
"https://dcdn.example.com/cache-management/",
"trigger-versions": [ "2", "2.1" ],
"trigger-subjects": "content"
},
"footprints": {
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}
}
]
}
5.2. CI/T Trigger Scope Capability Object
The CI/T supports several trigger actions for different trigger
subjects as defined in Section 4.1.1 and Section 4.1.2.2. Additional
actions, as well as subjects, may be defined in the future. The
Trigger Scope capability object is used to indicate support for a
Trigger Action for a subject. It further specifies the Trigger
Generic Spec types that may be used for selecting the targets the
triggers are applied on, along with the supported Trigger Generic
Extension types.
The "trigger-scope-capability" object matches the "FCI.CITScope"
capability type and is encoded as a JSON object containing the
following name/value pairs:
Name: trigger-action
Description: The supported CDNI CI/T Trigger Action.
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Value: A string corresponding to an entry from the "CDNI CI/T
Trigger Types" registry Section 7.2, which corresponds to a
CDNI CI/T Trigger Action.
Mandatory: Yes.
Name: trigger-subject
Description: The supported CDNI CI/T Trigger Subject.
Value: A string corresponding to an entry from the "CDNI CI/T
Trigger Subjects" registry Section 7.4, which corresponds to a
CDNI CI/T Trigger Subject.
Mandatory: Yes.
Name: trigger-specs
Description: A list of supported CDNI CI/T GenericSpecObject
types for Trigger Action and Subject.
Value: List of strings corresponding to entries from the "CDNI
CI/T Trigger Specs" registry Section 7.3, which correspond to
CDNI CI/T GenericSpecObject objects.
Mandatory: No. The default, in case of a missing or an empty
list, MUST be interpreted as "no GenericExtensionObject types
are supported". A non-empty list MUST be interpreted as
containing "the only GenericExtensionObject types that are
supported".
Name: trigger-extensions
Description: A list of supported CDNI CI/T
GenericExtensionObject types for Trigger Action and Subject.
Value: List of strings corresponding to entries from the "CDNI
CI/T Trigger Extension" registry Section 7.6, which corresponds
to a CDNI CI/T GenericExtensionObject object.
Mandatory: No. The default, in case of a missing or an empty
list, MUST be interpreted as "no GenericExtensionObject types
are supported". A non-empty list MUST be interpreted as
containing "the only GenericExtensionObject types that are
supported".
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5.2.1. CI/T Trigger Scope Capability Object Serialization
The following shows an example of a JSON-serialized CI/T Trigger
Scope Capability object serialization for dCDN that supports the
preposition and invalidation of content, using "urls" and "ccids"
Generic Spec types, with "time-policy" but only for the "preposition"
action. Note that in this example, purge is not supported, and no
actions involving metadata are supported either.
{
"capabilities": [{
"capability-type": "FCI.CITScope",
"capability-value": {
"trigger-scope-capabilities": [
{
"trigger-action": "preposition",
"trigger-subject": "content",
"trigger-specs": [ "urls", "ccids" ],
"trigger-extensions": [ "time-policy" ]
},
{
"trigger-action": "invalidate",
"trigger-subject": "content",
"trigger-specs": [ "urls", "ccids" ]
}
]
},
"footprints": {
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}
}]
}
5.3. CI/T Object List Type Capability Object
Given an object list being supported by dCDN, the CI/T Object List
Type capability object is used to indicate support for one or more
Object List types listed in Section 7.5 by the type property of the
"ObjectList" object. The capability type is "FCI.CITObjectListType".
Name: object-list-types
Description: A list of supported ObjectList types.
Value: An array of Section 4.3.2.1.
Mandatory: No. In case of a missing or an empty list, MUST be
interpreted as no ObjectList types are supported.
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5.3.1. CI/T Object List Type Capability Object Serialization
The following shows an example of a JSON-serialized CI/T Object List
Type Capability object serialization for dCDN that supports "hls" and
"dash".
{
"capabilities": [{
"capability-type": "FCI.CITObjectListType",
"capability-value": {
"object-list-types": [ "hls", "dash", "json" ]
},
"footprints": {
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}
}]
}
5.4. CI/T Private URL Capability Object
The CI/T Private URL capability object is used to indicate support
for operations on private URLs (see Section 4.3.1 for details). The
capability type is "FCI.CITPrivateUrlType".
Name: private-url-type-support
Description: Indicate whether private URL type is supported by
dCDN.
Value: Boolean.
Mandatory: No. In case of missing or an empty attribute, MUST
be interpreted as no support for private URLs.
5.4.1. CI/T Private URL Type Capability Object Serialization
The following shows an example of a JSON-serialized CI/T Private URL
Type Capability object serialization for dCDN that supports the
private URL type in URL-based trigger spec types.
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{
"capabilities": [{
"capability-type": "FCI.CITPrivateUrlType",
"capability-value": { "private-url-type-support": true },
"footprints": {
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}
}]
}
5.5. CI/T Extended Status Capability Object
CI/T Extended Trigger Status Capability object is used to indicate
support for extended trigger status. The extended trigger status is
returned upon uCDN request and includes:
* "objects" attribute in top-level Trigger object
* "objects" attribute in Error.v2 Description object
* "all-triggers" attribute in top-level Trigger Collections object
The capability type is "FCI.CITExtendedStatus".
Name: extended-status-objects
Description: List of CI/T objects that support extended
attributes.
Value: An array of JSON strings listing CI/T objects.
Mandatory: No. By default, in case of a missing or an empty
list, no extended attribute objects are supported.
5.5.1. CI/T Private URL Type Capability Object Serialization
The following shows an example of a JSON-serialized CI/T Extended
Status Type Capability object serialization for dCDN that supports
extended status in Trigger, Error.v2 Description and Trigger
Collections objects.
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{
"capabilities": [{
"capability-type": "FCI.CITExtendedStatus",
"capability-value": {
"extended-status-objects": [
"trigger-state" ,
"error-v2-description",
"trigger-collection"
]
},
"footprints": {
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}
}]
}
6. Examples
The following subsections provide examples of different CI/T objects
encoded as JSON.
The discovery of the CI/T interface is out of scope of this document.
In an implementation, all CI/T URLs are under the control of the
dCDN. uCDN MUST NOT attempt to ascribe any meaning to individual
elements of the path.
In examples in this section, the URL "https://dcdn.example.com/
triggers" is used as the location of the collection of all Trigger
Status Resources, and the CDN PID of uCDN is "AS64496:1".
6.1. Creating Triggers
Examples of uCDN triggering activity in dCDN:
6.1.1. Preposition
Below is an example of a "preposition" trigger -- a POST to the
collection of all triggers.
Note that pattern-based specs like "UriPatternMatch" and
"UrisRegexMatch" are not allowed in a preposition Trigger
Specification, where dCDN has to have a clear list of objects to
obtain.
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REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger.v2
Content-Length: 352
{
"action": "preposition",
"specs": [
{
"trigger-subject": "metadata",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [ "https://metadata.example.com/a/b/c" ]
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [
"https://www.example.com/a/b/c/1",
"https://www.example.com/a/b/c/2",
"https://www.example.com/a/b/c/3",
"https://www.example.com/a/b/c/4"
]
}
}
],
"cdn-path": [ "AS64496:1" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger.v2
Location: https://dcdn.example.com/triggers/0
Server: example-server/0.1
{
"ctime": 1462351690,
"etime": 1462351698,
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"mtime": 1462351690,
"state": "pending",
"action": "preposition",
"specs": [
{
"trigger-subject": "metadata",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [ "https://metadata.example.com/a/b/c" ]
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [
"https://www.example.com/a/b/c/1",
"https://www.example.com/a/b/c/2",
"https://www.example.com/a/b/c/3",
"https://www.example.com/a/b/c/4"
]
}
}
],
"cdn-path": [ "AS64496:1" ]
}
6.1.2. Invalidate
Below is an example of a CI/T "invalidate" trigger -- another POST to
the collection of all triggers. This instructs the dCDN to
revalidate the content at "https://www.example.com/a/index.html", as
well as any metadata and content whose URLs are prefixed by
"https://metadata.example.com/a/b/" using case-insensitive matching,
and "https://www.example.com/a/b/" using case-sensitive matching,
respectively.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger.v2
Content-Length: 387
{
"action": "invalidate",
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"specs": [
{
"trigger-subject": "metadata",
"generic-trigger-spec-type": "uri-pattern-match",
"generic-trigger-spec-value": {
"pattern": "https://metadata.example.com/a/b/*"
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [
"https://www.example.com/a/index.html"
]
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "uri-pattern-match",
"generic-trigger-spec-value": {
"pattern": "https://www.example.com/a/b/*",
"case-sensitive": true
}
}
],
"cdn-path": [ "AS64496:1" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:11 GMT
Content-Length: 545
Content-Type: application/cdni; ptype=ci-trigger.v2
Location: https://dcdn.example.com/triggers/1
Server: example-server/0.1
{
"ctime": 1462351691,
"etime": 1462351699,
"mtime": 1462351691,
"state": "pending",
"action": "invalidate",
"specs": [
{
"trigger-subject": "metadata",
"generic-trigger-spec-type": "uri-pattern-match",
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"generic-trigger-spec-value": {
"pattern": "https://metadata.example.com/a/b/*"
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [ "https://www.example.com/a/index.html" ]
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "uri-pattern-match",
"generic-trigger-spec-value": {
"pattern": "https://www.example.com/a/b/*",
"case-sensitive": true
}
}
],
"cdn-path": [ "AS64496:1" ]
}
6.1.3. Invalidation with Regex
In the following example, a CI/T "invalidate" trigger uses the Regex
property to specify the range of content objects for invalidation,
the trigger is rejected by dCDN due to regex complexity, and an
appropriate error is reflected in the response.
Please note that some lines in the example are wrapped for clarity.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger.v2
{
"action": "invalidate",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "uri-regex-match",
"generic-trigger-spec-value": {
"regex": "^(https:\\/\\/video\\.example\\.com)\\/
([a-z])\\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
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"case-sensitive": true,
"match-query-string": false
}
}],
"cdn-path": [ "AS64496:0" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger.v2
Location: https://triggers.dcdn.example.com/triggers/2
Server: example-server/0.1
{
"errors": [{
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "uri-regex-match",
"generic-trigger-spec-value": {
"regex": "^(https:\\/\\/video\\.example\\.com)\\/([a-z])\
\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
"case-sensitive": true,
"match-query-string": false
}
}],
"description": "dCDN rejected a regex due to complexity",
"error": "ereject",
"cdn": "AS64500:0"
}],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"state": "failed",
"action": "invalidate",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "uri-regex-match",
"generic-trigger-spec-value": {
"regex": "^(https:\\/\\/video\\.example\\.com)\\/([a-z])\
\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
"case-sensitive": true,
"match-query-string": false
}
}],
"cdn-path": [ "AS64496:0" ]
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}
6.1.4. Preposition with ObjectLists
In the following example, a CI/T "preposition" trigger uses the
ObjectList property to specify the full media library of a specific
content. The command fails due to object list parse error and an
appropriate error is reflected in the status response.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger.v2
{
"action": "preposition",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "content-objectlist",
"generic-trigger-spec-value": {
"objects": [{
"href": "https://www.example.com/hls/title/index.m3u8",
"type": "hls"
}]
}
}],
"cdn-path": [ "AS64496:0" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger.v2
Location: https://triggers.dcdn.example.com/triggers/3
Server: example-server/0.1
{
"errors": [{
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "content-objectlist",
"generic-trigger-spec-value": {
"objects": [{
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"href": "https://www.example.com/hls/title/index.m3u8",
"type": "hls"
}}
}],
"description": "dCDN was not able to parse the object list",
"error": "econtent",
"cdn": "AS64500:0"
}],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"state": "failed",
"action": "preposition",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "content-objectlist",
"generic-trigger-spec-value": {
"objects": [{
"href": "https://www.example.com/hls/title/index.m3u8",
"type": "hls"
}]
}
}],
"cdn-path": [ "AS64496:0" ]
}
6.2. Examining Trigger Status
Once triggers have been created, uCDN can check their status as shown
in the following examples.
6.2.1. Collection of All Triggers
uCDN can fetch the collection of all triggers it has created that
have not yet been deleted or expired. After the creation of the
"preposition" and "invalidate" triggers shown above, this collection
might look as follows:
REQUEST:
GET /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
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Content-Length: 341
Expires: Wed, 04 May 2016 08:49:11 GMT
Server: example-server/0.1
ETag: "-936094426920308378"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:11 GMT
Content-Type: application/cdni; ptype=ci-trigger-collection
{
"cdn-id": "AS64496:0",
"coll-status": [
{
"status" : "pending",
"collection": "/triggers/pending"
},
{
"status" : "active",
"collection": "/triggers/active"
},
{
"status" : "complete",
"collection": "/triggers/complete"
},
{
"status" : "processed",
"collection": "/triggers/processed"
},
{
"status" : "failed",
"collection": "/triggers/failed"
},
{
"status" : "cancelling",
"collection": "/triggers/cancelling"
},
{
"status" : "cancelled",
"collection": "/triggers/cancelled"
}
],
"coll-label": [
{
"label" : "1b1bad0c",
"collection": "/triggers/1b1bad0c"
},
{
"label" : "fafa9a97",
"collection": "/triggers/fafa9a97"
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}
],
"staleresourcetime": 86400,
"triggers": [
"https://dcdn.example.com/triggers/0",
"https://dcdn.example.com/triggers/1"
]
}
6.2.2. Filtered Collections of Triggers
The filtered collections are also available to uCDN. Before the dCDN
starts processing the two triggers shown above, both will appear in
the collection of pending triggers. For example:
REQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 152
Expires: Wed, 04 May 2016 08:49:11 GMT
Server: example-server/0.1
ETag: "4331492443626270781"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:11 GMT
Content-Type: application/cdni; ptype=ci-trigger-collection
{
"staleresourcetime": 86400,
"triggers": [
"https://dcdn.example.com/triggers/0",
"https://dcdn.example.com/triggers/1"
]
}
At this point, if no other triggers had been created, the other
filtered views would be empty. For example:
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REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 54
Expires: Wed, 04 May 2016 08:49:11 GMT
Server: example-server/0.1
ETag: "7958041393922269003"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:11 GMT
Content-Type: application/cdni; ptype=ci-trigger-collection
{
"staleresourcetime": 86400,
"triggers": []
}
6.2.3. Individual Trigger Resources
uCDN can also examine individual triggers. For example, for the
"preposition" and "invalidate" triggers from previous examples:
REQUEST:
GET /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 467
Expires: Wed, 04 May 2016 08:49:10 GMT
Server: example-server/0.1
ETag: "6990548174277557683"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Type: application/cdni; ptype=ci-trigger.v2
{
"ctime": 1462351690,
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"etime": 1462351698,
"mtime": 1462351690,
"status": "pending",
"action": "preposition",
"specs": [
{
"trigger-subject": "metadata",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [ "https://metadata.example.com/a/b/c" ]
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [
"https://www.example.com/a/b/c/1",
"https://www.example.com/a/b/c/2",
"https://www.example.com/a/b/c/3",
"https://www.example.com/a/b/c/4"
]
}
}
]
}
REQUEST:
GET /triggers/1 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 545
Expires: Wed, 04 May 2016 08:49:11 GMT
Server: example-server/0.1
ETag: "-554385204989405469"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:11 GMT
Content-Type: application/cdni; ptype=ci-trigger.v2
{
"ctime": 1462351691,
"etime": 1462351699,
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"mtime": 1462351691,
"status": "pending",
"action": "invalidate",
"specs": [
{
"trigger-subject": "metadata",
"generic-trigger-spec-type": "uri-pattern-match",
"generic-trigger-spec-value": {
"pattern": "https://metadata.example.com/a/b/*"
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "urls",
"generic-trigger-spec-value": {
"urls": [ "https://www.example.com/a/index.html" ]
}
},
{
"trigger-subject": "content",
"generic-trigger-spec-type": "uri-pattern-match",
"generic-trigger-spec-value": {
"pattern": "https://www.example.com/a/b/*",
"case-sensitive": true
}
}
]
}
6.2.4. Polling for Changes in Status
uCDN SHOULD use the ETags of collections or triggers when polling for
changes in status, as shown in the following examples:
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REQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
If-None-Match: "4331492443626270781"
RESPONSE:
HTTP/1.1 304 Not Modified
Content-Length: 0
Expires: Wed, 04 May 2016 08:49:11 GMT
Server: example-server/0.1
ETag: "4331492443626270781"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:11 GMT
Content-Type: application/cdni; ptype=ci-trigger-collection
REQUEST:
GET /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
If-None-Match: "6990548174277557683"
RESPONSE:
HTTP/1.1 304 Not Modified
Content-Length: 0
Expires: Wed, 04 May 2016 08:49:10 GMT
Server: example-server/0.1
ETag: "6990548174277557683"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Type: application/cdni; ptype=ci-trigger.v2
When the trigger processing is complete, the contents of the filtered
collections will be updated along with their ETags. For example,
when the two example triggers are complete, the collections of
pending and complete triggers look as follows:
REQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
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RESPONSE:
HTTP/1.1 200 OK
Content-Length: 54
Expires: Wed, 04 May 2016 08:49:15 GMT
Server: example-server/0.1
ETag: "1337503181677633762"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:15 GMT
Content-Type: application/cdni; ptype=ci-trigger-collection
{
"staleresourcetime": 86400,
"triggers": []
}
REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 152
Expires: Wed, 04 May 2016 08:49:22 GMT
Server: example-server/0.1
ETag: "4481489539378529796"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:22 GMT
Content-Type: application/cdni; ptype=ci-trigger-collection
{
"staleresourcetime": 86400,
"triggers": [
"https://dcdn.example.com/triggers/0",
"https://dcdn.example.com/triggers/1"
]
}
6.2.5. Deleting Triggers
uCDN can delete completed and failed triggers to reduce the size of
the collections, as described in Section 3.5. For example, to delete
the "preposition" trigger from earlier examples:
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REQUEST:
DELETE /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 204 No Content
Date: Wed, 04 May 2016 08:48:22 GMT
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Server: example-server/0.1
This would, for example, cause the collection of completed Trigger
Status Resources shown in the example above, to be updated to:
REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 105
Expires: Wed, 04 May 2016 08:49:22 GMT
Server: example-server/0.1
ETag: "-6938620031669085677"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:22 GMT
Content-Type: application/cdni; ptype=ci-trigger-collection
{
"staleresourcetime": 86400,
"triggers": [ "https://dcdn.example.com/triggers/1" ]
}
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6.2.6. Extensions with Error Propagation
In the following example, a CI/T "preposition" command is using two
extensions to control the way the trigger is executed. In this
example, the receiving dCDN, identified as "AS64500:0", does not
support the first extension in the extensions array. dCDN "AS64500:0"
further distributes this trigger to another downstream CDN that is
identified as "AS64501:0", which does not support the second
extension in the extensions array. The error is propagated from
"AS64501:0" to "AS64500:0" and the errors.v2 array reflects both
errors.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger.v2
{
"action": "preposition",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "content-objectlist",
"generic-trigger-spec-value": {
"objects": [{
"href": "https://www.example.com/hls/title/index.m3u8",
"type": "hls"
}]
}
}],
"extensions": [
{
"generic-trigger-extension-type": "location-policy",
"generic-trigger-extension-value": {
"locations": [
{
"action": "allow",
"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}]
},
{
"action": "deny",
"footprints": [{
"footprint-type": "countrycode",
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"footprint-value": [ "ca" ]
}]
}
]
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true
},
{
"generic-trigger-extension-type": "time-policy",
"generic-trigger-extension-value": {
"unix-time-window": {
"start": 946717200,
"end": 946746000
}
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true
}
],
"cdn-path": [ "AS64496:0" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger.v2
Location: https://triggers.dcdn.example.com/triggers/0
Server: example-server/0.1
{
"errors": [
{
"extensions": [{
"generic-trigger-extension-type": "location-policy",
"generic-trigger-extension-value": {
"locations": [
{
"action": "allow",
"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}]
},
{
"action": "deny",
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"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "ca" ]
}]
}
]
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true
}],
"description": "unrecognized extension type",
"error": "eextension",
"cdn": "AS64500:0"
},
{
"extensions": [{
"generic-trigger-extension-type": "time-policy",
"generic-trigger-extension-value": {
"unix-time-window": {
"start": 946717200,
"end": 946746000
}
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true
}],
"description": "unrecognized extension type",
"error": "eextension",
"cdn": "AS64501:0"
}
],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"status": "failed",
"action": "preposition",
"specs": [{
"trigger-subject": "content",
"generic-trigger-spec-type": "content-objectlist",
"generic-trigger-spec-value": {
"objects": [{
"href": "https://www.example.com/hls/title/index.m3u8",
"type": "hls"
}]
}
}],
"extensions": [
{
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"generic-trigger-extension-type": "location-policy",
"generic-trigger-extension-value": {
"locations": [
{
"action": "allow",
"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "us" ]
}]
},
{
"action": "deny",
"footprints": [{
"footprint-type": "countrycode",
"footprint-value": [ "ca" ]
}]
}
]
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true
},
{
"generic-trigger-extension-type": "time-policy",
"generic-trigger-extension-value": {
"unix-time-window": {
"start": 946717200,
"end": 946746000
}
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true
}
],
"cdn-path": [ "AS64496:0" ]
}
7. IANA Considerations
7.1. CDNI Payload Type Parameter Registrations
All references to RFC 8007 in the IANA registries should be replaced
with references to this document, apart from references associated
with the following registrations:
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+=======================+===============+
| Payload Type | Specification |
+=======================+===============+
| ci-trigger-command | RFC 8007 |
+-----------------------+---------------+
| ci-trigger-status | RFC 8007 |
+-----------------------+---------------+
| ci-trigger-collection | RFC 8007 |
+-----------------------+---------------+
Table 11
The IANA is requested to register the following new Payload Types in
the "CDNI Payload Types" registry defined by [RFC7736], for use with
the "application/cdni" MIME media type.
+=======================+===============+
| Payload Type | Specification |
+=======================+===============+
| ci-trigger.v2 | RFCthis |
+-----------------------+---------------+
| FCI.CITObjectsVersion | RFCthis |
+-----------------------+---------------+
| FCI.CITScope | RFCthis |
+-----------------------+---------------+
| FCI.CITObjectListType | RFCthis |
+-----------------------+---------------+
Table 12
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
7.1.1. CDNI ci-trigger.v2 Payload Type
Purpose: The purpose of this payload type is to define a new CI/T
trigger object (and any associated capability advertisement)
Interface: CI/T
Encoding: see Section 4.1
7.1.2. CDNI FCI CI/T Payload Types
7.1.2.1. CDNI FCI CI/T Endpoints Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for CI/T Endpoints objects
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Interface: FCI
Encoding: see Section 5.1
7.1.2.2. CDNI FCI CI/T Trigger Scope Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for CI/T Trigger Scope
Interface: FCI
Encoding: see Section 5.2.1
7.1.2.3. CDNI FCI CI/T Object List Type Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for CI/T Object List Type objects
Interface: FCI
Encoding: see Section 5.3
7.2. "CDNI CI/T Trigger Types" Registry For Trigger Actions
In [RFC8007] the IANA was requested to create a new "CDNI CI/T
Trigger Types" registry under the "Content Delivery Network
Interconnection (CDNI) Parameters" registry group.
Additions to the "CDNI CI/T Trigger Types" registry are made via the
RFC Required policy as defined in [RFC8126].
In this second edition of the interface, trigger types are referred
to as "trigger actions". The "Trigger Types" registry is used for
action definitions. Furthermore, this document, and specifically
Section 4.1.1, reuses the definition of "trigger types" as defined in
[RFC8007] as trigger actions, and provide their specifications, with
no modification compared to [RFC8007].
7.3. "CDNI CI/T Trigger Specs" Registry
The IANA is requested to create a new "CDNI CI/T Trigger Specs"
registry in the "Content Delivery Networks Interconnection (CDNI)
Parameters" registry group. The "CDNI CI/T Trigger Specs" namespace
defines the valid trigger targets' spec values in Section 4.1.2, used
by the Trigger Spec object.
Additions to the "CDNI CI/T Trigger Specs" registry are made via the
RFC Required policy as defined in [RFC8126].
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The initial contents of the "CDNI CI/T Trigger Specs" registry
comprise the names and descriptions listed in Section 4.1.2, with
this document acting as the specification.
7.4. "CDNI CI/T Trigger Subjects" Registry
The IANA is requested to create a new "CDNI CI/T Trigger Subjects"
registry in the "Content Delivery Networks Interconnection (CDNI)
Parameters" registry group. The "CDNI CI/T Trigger Subjects"
namespace defines the valid trigger targets' subject values in
Section 4.1.2.2, used by the Trigger Spec object.
Additions to the "CDNI CI/T Trigger Subjects" registry are made via
the RFC Required policy as defined in [RFC8126].
The initial contents of the "CDNI CI/T Trigger Subjects" registry
comprise the names and descriptions listed in Section 4.1.2.2, with
this document acting as the specification.
7.5. "CDNI CI/T Object List Types" Registry
The IANA is requested to create a new "CDNI CI/T Object List Types"
registry in the "Content Delivery Networks Interconnection (CDNI)
Parameters" registry group. The "CDNI CI/T Object List Types"
namespace defines the valid object list type values in
Section 4.3.2.1, used by the Object List object.
Additions to the "CDNI CI/T Object List Types" registry are made via
the RFC Required policy as defined in [RFC8126].
The initial contents of the "CDNI CI/T Object List Types" registry
comprise the names and descriptions listed in Section 4.3.2.1, with
this document acting as the specification.
7.6. "CDNI CI/T Trigger Extensions" Registry
The IANA is requested to create a new "CDNI CI/T Trigger Extensions"
registry in the "Content Delivery Networks Interconnection (CDNI)
Parameters" registry group. The "CDNI CI/T Trigger Extensions"
namespace defines the valid trigger targets' extension values in
Section 2.7, used by the Trigger Spec object.
Additions to the "CDNI CI/T Trigger Extensions" registry are made via
the RFC Required policy as defined in [RFC8126].
The initial contents of the "CDNI CI/T Trigger Extensions" registry
comprise the names and descriptions listed in Section 2.7, with this
document acting as the specification.
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7.7. "CDNI CI/T Error Codes" Registry
In [RFC8007] the IANA was requested to create a new "CDNI CI/T Error
Codes" registry under the "Content Delivery Network Interconnection
(CDNI) Parameters" registry group.
Additions to the "CDNI CI/T Error Codes" registry are made via the
Specification Required policy as defined in [RFC8126]. The
Designated Expert will verify that new Error Code registrations do
not duplicate existing Error Code definitions (in name or
functionality), prevent gratuitous additions to the namespace, and
prevent any additions to the namespace that would impair the
interoperability of CDNI implementations.
In this second edition of the interface, we list and repeat the
definition of the Error Codes from [RFC8007] - acting as the entities
specification with no modification compared to [RFC8007].
Additionally, the IANA is requested to register three additional
error codes, "espec", "esubject" and "eextension", with specification
as defined in Section 4.1.5.2.
7.8. "CDNI CI/T URL Types" Registry
The IANA is requested to create a new "CDNI CI/T URL types" registry
in the "Content Delivery Networks Interconnection (CDNI) Parameters"
registry group. The "CDNI CI/T URL Types" namespace defines the
valid URL type values in Section 4.3.1, used by Section 4.1.2.3,
Section 4.1.2.5, Section 4.1.2.6 and Section 4.1.2.7.
The initial contents of the "CDNI CI/T Trigger Extensions" registry
comprise the names and descriptions listed in Section 4.3.1, with
this document acting as the specification.
8. Security Considerations
The CI/T interface provides a mechanism to allow uCDN to generate
requests into dCDN and to inspect its own CI/T requests and their
current states. The CI/T interface does not allow access to, or
modification of, uCDN or dCDN metadata relating to content delivery
or to the content itself. It can only control the presence of that
metadata in dCDN, and the processing work and network utilization
involved in ensuring that presence.
By examining "preposition" requests to dCDN, and correctly
interpreting content and metadata URLs, an attacker could learn the
uCDN's or content owner's predictions for future content popularity.
By examining "invalidate" or "purge" requests, an attacker could
learn about changes in the content owner's catalog.
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By injecting CI/T triggers, an attacker or a misbehaving uCDN would
generate work in dCDN and uCDN as they process those requests. So
would a man-in-the-middle attacker modify valid trigger requests
generated by uCDN. In both cases, that would decrease dCDN's caching
efficiency by causing it to unnecessarily acquire or reacquire
content metadata and/or content.
dCDN implementation of CI/T MUST restrict the actions of uCDN to the
data corresponding to that uCDN. Failure to do so would allow uCDNs
to detrimentally affect each other's efficiency by generating
unnecessary acquisition or reacquisition load.
An origin that chooses to delegate its delivery to a CDN is trusting
that CDN to deliver content on its behalf; the interconnection of
CDNs is an extension of that trust to dCDNs. That trust relationship
is a commercial arrangement, outside the scope of the CDNI protocols.
So, while a malicious CDN could deliberately generate load on dCDN
using the CI/T interface, the protocol does not otherwise attempt to
address malicious behavior between interconnected CDNs.
8.1. Authentication, Authorization, Confidentiality, Integrity
Protection
A CI/T implementation MUST support Transport Layer Security (TLS)
transport for HTTP (HTTPS) as per [RFC9110].
TLS MUST be used by the server side (dCDN) and the client side (uCDN)
of the CI/T interface, including the authentication of the remote
end, unless alternate methods are used to ensure the security of the
information in the CI/T interface requests and responses (such as
setting up an IPsec tunnel between the two CDNs or using a physically
secured internal network between two CDNs that are owned by the same
corporate entity).
The use of TLS for transport of the CI/T interface allows dCDN and
uCDN to authenticate each other using the TLS client authentication
and TLS server authentication.
Once dCDN and uCDN have mutually authenticated each other, TLS
allows:
* dCDN and uCDN to authorize each other (to ensure that they are
receiving trigger requests from, or responding to, an authorized
CDN).
* CDNI commands and responses to be transmitted with
confidentiality.
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* Protection of the integrity of CDNI commands and responses.
When TLS is used, the general TLS usage guidance in [RFC9325] MUST be
followed.
The mechanisms for access control are dCDN-specific and are not
standardized as part of this CI/T specification.
HTTP requests that attempt to access or operate on CI/T data
belonging to another CDN MUST be rejected using, for example, HTTP
403 ("Forbidden") or 404 ("Not Found"). This is intended to prevent
unauthorized users from generating unnecessary load in dCDNs or uCDNs
due to revalidation, reacquisition, or unnecessary acquisition.
When deploying a network of interconnected CDNs, the possible
inefficiencies related to the diamond configuration discussed in
Section 2.8 should be considered.
8.2. Denial of Service
This document does not define a specific mechanism to protect against
Denial-of-Service (DoS) attacks on the CI/T interface. However, CI/T
endpoints can be protected against DoS attacks through the use of TLS
transport and/or via mechanisms outside the scope of the CI/T
interface, such as firewalling or the use of Virtual Private Networks
(VPNs).
Depending on the implementation, triggered activity may consume
significant processing and bandwidth in dCDN. A malicious or faulty
uCDN could use this to generate unnecessary load in dCDN. dCDN
should consider mechanisms to avoid overload -- for example, by rate-
limiting acceptance or processing of triggers, or by performing batch
processing.
8.3. Privacy
The CI/T protocol does not carry any information about individual end
users of a CDN; there are no privacy concerns for end users.
The CI/T protocol does carry information that could be considered
commercially sensitive by CDN operators and content owners. The use
of mutually authenticated TLS to establish a secure session for the
transport of CI/T data, as discussed in Section 8.1, provides
confidentiality while the CI/T data is in transit and prevents
parties other than the authorized dCDN from gaining access to that
data. dCDN MUST ensure that it only exposes CI/T data related to uCDN
to clients it has authenticated as belonging to that uCDN.
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9. References
9.1. Normative References
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System (AS)",
BCP 6, RFC 1930, DOI 10.17487/RFC1930, March 1996,
<https://www.rfc-editor.org/info/rfc1930>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC8006] Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
"Content Delivery Network Interconnection (CDNI)
Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
<https://www.rfc-editor.org/info/rfc8006>.
[RFC8007] Murray, R. and B. Niven-Jenkins, "Content Delivery Network
Interconnection (CDNI) Control Interface / Triggers",
RFC 8007, DOI 10.17487/RFC8007, December 2016,
<https://www.rfc-editor.org/info/rfc8007>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
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[RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", STD 97, RFC 9110,
DOI 10.17487/RFC9110, June 2022,
<https://www.rfc-editor.org/info/rfc9110>.
[RFC9112] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP/1.1", STD 99, RFC 9112, DOI 10.17487/RFC9112,
June 2022, <https://www.rfc-editor.org/info/rfc9112>.
[RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/info/rfc9325>.
[RFC9562] Davis, K., Peabody, B., and P. Leach, "Universally Unique
IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May
2024, <https://www.rfc-editor.org/info/rfc9562>.
9.2. Informative References
[ECMA404] ECMA International, "ECMA-404 - The JSON data interchange
syntax", Edition 2, December 2017, <https://ecma-
international.org/publications-and-standards/standards/
ecma-404/>.
[ISO8601] ISO, "Data elements and interchange formats -- Information
interchange -- Representation of dates and times",
ISO 8601:2004, Edition 3, December 2004,
<https://www.iso.org/standard/40874.html>.
[MPEG-DASH]
ISO, "Information technology -- Dynamic adaptive streaming
over HTTP (DASH) -- Part 1: Media presentation description
and segment format", ISO/IEC 23009-1:2014, Edition 2, May
2014, <https://www.iso.org/standard/65274.html>.
[MSS] Microsoft, "[MS-SSTR]: Smooth Streaming Protocol",
Protocol Revision 8.0, September 2017,
<https://msdn.microsoft.com/en-us/library/ff469518.aspx>.
[POSIX.1] "The Open Group Base Specifications Issue 7", IEEE
Std 1003.1 2018 Edition, 31 January 2018,
<http://pubs.opengroup.org/onlinepubs/9699919799/>.
[REST] Fielding, R., "Architectural Styles and the Design of
Network-based Software Architectures", Ph.D. Dissertation,
University of California, Irvine , 2000.
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[RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
Distribution Network Interconnection (CDNI) Problem
Statement", RFC 6707, DOI 10.17487/RFC6707, September
2012, <https://www.rfc-editor.org/info/rfc6707>.
[RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
August 2014, <https://www.rfc-editor.org/info/rfc7336>.
[RFC7337] Leung, K., Ed. and Y. Lee, Ed., "Content Distribution
Network Interconnection (CDNI) Requirements", RFC 7337,
DOI 10.17487/RFC7337, August 2014,
<https://www.rfc-editor.org/info/rfc7337>.
[RFC7736] Ma, K., "Content Delivery Network Interconnection (CDNI)
Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
December 2015, <https://www.rfc-editor.org/info/rfc7736>.
[RFC7975] Niven-Jenkins, B., Ed. and R. van Brandenburg, Ed.,
"Request Routing Redirection Interface for Content
Delivery Network (CDN) Interconnection", RFC 7975,
DOI 10.17487/RFC7975, October 2016,
<https://www.rfc-editor.org/info/rfc7975>.
[RFC8216] Pantos, R., Ed. and W. May, "HTTP Live Streaming",
RFC 8216, DOI 10.17487/RFC8216, August 2017,
<https://www.rfc-editor.org/info/rfc8216>.
Acknowledgments
The authors thank Kevin Ma for his input, and Carsten Bormann for his
review and formalization of the JSON data.
Authors' Addresses
Nir B. Sopher
Qwilt
6, Ha'harash
Hod HaSharon 4524079
Israel
Email: nir@apache.org
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Ori Finkelman
Qwilt
6, Ha'harash
Hod HaSharon 4524079
Israel
Email: ori.finkelman.ietf@gmail.com
Sanjay Mishra
Verizon
13100 Columbia Pike
Silver Spring, MD 20904
United States of America
Email: sanjay.mishra@verizon.com
Jay K. Robertson
Qwilt
275 Shoreline Dr Ste 510
Redwood City, CA 94065
United States of America
Email: jayrobertson@acm.org
Alan Arolovitch
Viasat
1295 Beacon street Unit 249
Brookline, MA 02446
United States of America
Email: alan.arolovitch@gmail.com
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