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2	Network Working Group                                       O. Finkelman
3	Internet-Draft                                                     Qwilt
4	Updates: 8007 (if approved)                                    S. Mishra
5	Intended status: Standards Track                                 Verizon
6	Expires: June 26, 2021                                         N. Sopher
7	                                                                   Qwilt
8	                                                       December 23, 2020

10	               CDNI Control Triggers Interface Extensions
11	                 draft-ietf-cdni-triggers-extensions-07

13	Abstract

15	   Open Caching architecture is a use case of Content Delivery Network
16	   Interconnection (CDNI) in which the commercial Content Delivery
17	   Network (CDN) is the upstream CDN (uCDN) and the ISP caching layer
18	   serves as the downstream CDN (dCDN).  This document defines
19	   extensions to the Content Delivery Network Interconnection (CDNI)
20	   Control Interface/Triggers defined in RFC 8007.  These extensions are
21	   derived from requirements raised by Open Caching architecture but are
22	   also applicable to CDNI use cases in general.

24	Requirements Language

26	   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
27	   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
28	   document are to be interpreted as described in RFC 2119 [RFC2119].

30	Status of This Memo

32	   This Internet-Draft is submitted in full conformance with the
33	   provisions of BCP 78 and BCP 79.

35	   Internet-Drafts are working documents of the Internet Engineering
36	   Task Force (IETF).  Note that other groups may also distribute
37	   working documents as Internet-Drafts.  The list of current Internet-
38	   Drafts is at https://datatracker.ietf.org/drafts/current/.

40	   Internet-Drafts are draft documents valid for a maximum of six months
41	   and may be updated, replaced, or obsoleted by other documents at any
42	   time.  It is inappropriate to use Internet-Drafts as reference
43	   material or to cite them other than as "work in progress."

45	   This Internet-Draft will expire on June 26, 2021.

47	Copyright Notice

49	   Copyright (c) 2020 IETF Trust and the persons identified as the
50	   document authors.  All rights reserved.

52	   This document is subject to BCP 78 and the IETF Trust's Legal
53	   Provisions Relating to IETF Documents
54	   (https://trustee.ietf.org/license-info) in effect on the date of
55	   publication of this document.  Please review these documents
56	   carefully, as they describe your rights and restrictions with respect
57	   to this document.  Code Components extracted from this document must
58	   include Simplified BSD License text as described in Section 4.e of
59	   the Trust Legal Provisions and are provided without warranty as
60	   described in the Simplified BSD License.

62	Table of Contents

64	   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
65	     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
66	     1.2.  Structure of this document  . . . . . . . . . . . . . . .   4
67	   2.  Interfaces Extensions Overview  . . . . . . . . . . . . . . .   5
68	     2.1.  CDNI Control Interface / Triggers Extensions  . . . . . .   5
69	       2.1.1.  CI/T Objects  . . . . . . . . . . . . . . . . . . . .   5
70	       2.1.2.  Trigger Specification . . . . . . . . . . . . . . . .   5
71	       2.1.3.  Content Selection . . . . . . . . . . . . . . . . . .   5
72	       2.1.4.  Trigger Extensibility . . . . . . . . . . . . . . . .   6
73	       2.1.5.  Error Handling  . . . . . . . . . . . . . . . . . . .   6
74	     2.2.  CDNI Footprint and Capabilities Interface Extensions  . .   7
75	   3.  CI/T Version 2  . . . . . . . . . . . . . . . . . . . . . . .   7
76	     3.1.  CI/T Objects V2 . . . . . . . . . . . . . . . . . . . . .   7
77	     3.2.  Error Handling V2 . . . . . . . . . . . . . . . . . . . .  10
78	       3.2.1.  Extension Errors  . . . . . . . . . . . . . . . . . .  10
79	       3.2.2.  Error propagation . . . . . . . . . . . . . . . . . .  11
80	     3.3.  Properties of CI/T Version 2 objects  . . . . . . . . . .  13
81	       3.3.1.  Trigger Specification Version 2 . . . . . . . . . . .  14
82	       3.3.2.  RegexMatch  . . . . . . . . . . . . . . . . . . . . .  15
83	       3.3.3.  Playlist  . . . . . . . . . . . . . . . . . . . . . .  16
84	       3.3.4.  MediaProtocol . . . . . . . . . . . . . . . . . . . .  17
85	       3.3.5.  CI/T Trigger Extensions . . . . . . . . . . . . . . .  17
86	         3.3.5.1.  Enforcement Options . . . . . . . . . . . . . . .  17
87	         3.3.5.2.  GenericExtensionObject  . . . . . . . . . . . . .  20
88	       3.3.6.  Error Description Version 2 . . . . . . . . . . . . .  22
89	       3.3.7.  Error codes . . . . . . . . . . . . . . . . . . . . .  24
90	     3.4.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  24
91	       3.4.1.  Invalidation with Regex . . . . . . . . . . . . . . .  24
92	       3.4.2.  Preposition with Playlists  . . . . . . . . . . . . .  26
93	       3.4.3.  Extensions with Error Propagation . . . . . . . . . .  27
94	   4.  Trigger Extension Objects . . . . . . . . . . . . . . . . . .  29
95	     4.1.  LocationPolicy extension  . . . . . . . . . . . . . . . .  29
96	     4.2.  TimePolicy Extension  . . . . . . . . . . . . . . . . . .  31
97	       4.2.1.  UTCWindow . . . . . . . . . . . . . . . . . . . . . .  33
98	       4.2.2.  LocalTimeWindow . . . . . . . . . . . . . . . . . . .  34
99	       4.2.3.  DateLocalTime . . . . . . . . . . . . . . . . . . . .  35
100	         4.2.3.1.  Date and Local Time Format  . . . . . . . . . . .  35
101	         4.2.3.2.  Restrictions  . . . . . . . . . . . . . . . . . .  36
102	   5.  Footprint and Capabilities  . . . . . . . . . . . . . . . . .  36
103	     5.1.  CI/T Versions Capability Object . . . . . . . . . . . . .  36
104	       5.1.1.  CI/T Versions Capability Object Serialization . . . .  37
105	     5.2.  CI/T Playlist Protocol Capability Object  . . . . . . . .  37
106	       5.2.1.  CI/T Playlist Protocol Capability Object
107	               Serialization . . . . . . . . . . . . . . . . . . . .  37
108	     5.3.  CI/T Trigger Extension Capability Object  . . . . . . . .  38
109	       5.3.1.  CI/T Trigger Extension Capability Object
110	               Serialization . . . . . . . . . . . . . . . . . . . .  38
111	   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  39
112	     6.1.  CDNI Payload Types  . . . . . . . . . . . . . . . . . . .  39
113	       6.1.1.  CDNI ci-trigger-command.v2 Payload Type . . . . . . .  39
114	       6.1.2.  CDNI ci-trigger-status.v2 Payload Type  . . . . . . .  40
115	       6.1.3.  CDNI CI/T LocationPolicy Trigger Extension Type . . .  40
116	       6.1.4.  CDNI CI/T TimePolicy Trigger Extension Type . . . . .  40
117	       6.1.5.  CDNI FCI CI/T Versions Payload Type . . . . . . . . .  40
118	       6.1.6.  CDNI FCI CI/T Playlist Protocol Payload Type  . . . .  40
119	       6.1.7.  CDNI FCI CI/T Extension Objects Payload Type  . . . .  41
120	     6.2.  CDNI CI/T Trigger Error Codes types . . . . . . . . . . .  41
121	     6.3.  CDNI Media protocol types . . . . . . . . . . . . . . . .  41
122	   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  42
123	   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  42
124	   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  42
125	   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  43
126	     10.1.  Normative References . . . . . . . . . . . . . . . . . .  43
127	     10.2.  Informative References . . . . . . . . . . . . . . . . .  44
128	   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  45

130	1.  Introduction

132	   The Streaming Video Alliance [SVA] is a global association that works
133	   to solve streaming video challenges in an effort to improve end-user
134	   experience and adoption.  The Open Caching Working Group [OCWG] of
135	   the Streaming Video Alliance [SVA] is focused on the delegation of
136	   video delivery requests from commerical CDNs to a caching layer at
137	   the ISP's network.  Open Caching architecture is a specific use case
138	   of CDNI where the commercial CDN is the upstream CDN (uCDN) and the
139	   ISP caching layer is the downstream CDN (dCDN).  The Open Caching
140	   Content Management Operations Specification [OC-CM] defines objects
141	   and extensions required by Open Caching architecture for granular
142	   content management operations.  This document adds those extensions
143	   to the CDNI Control Interface / Triggers [RFC8007] as required for
144	   Open Caching content management options.  This document also
145	   specifies a generic extension mechanism to enable adding future
146	   functions for controlling the trigger execution>.

148	   The CDNI Metadata Interface is described in [RFC8006].

150	   The CDNI Footprint and Capability Interface is described in
151	   [RFC8008].

153	   The CDNI Control Interface / Triggers is described in [RFC8007].

155	   For consistency with other CDNI documents, this document follows the
156	   CDNI convention of uCDN (upstream CDN) and dCDN (downstream CDN) as
157	   described in [RFC6707] to represent the commercial CDN and ISP
158	   caching layer, respectively.

160	1.1.  Terminology

162	   This document reuses the terminology defined in [RFC6707], [RFC7736]
163	   [RFC8006], [RFC8007], and [RFC8008].

165	   Additionally, the following terms are used throughout this document
166	   and are defined as follows:

168	   o  HLS - HTTP Live Streaming

170	   o  DASH - Dynamic Adaptive Streaming Over HTTP

172	   o  MSS - Microsoft Smooth Streaming

174	1.2.  Structure of this document

176	   The remainder of this document is organized as follows:

178	   o  Section 2 gives an overview of the extensions specified in this
179	      document.

181	   o  Section 3 specifies version 2 of the CDNI Control Interface /
182	      Triggers.

184	   o  Section 4 specifies an initial set of trigger extension objects.

186	   o  Section 5 specifies Footprint and Capability objects for CI/T
187	      version and extensions.

189	   o  Section 6 list the IANA considerations of this document.

191	   o  Section 7 describes the security considerations for the specified
192	      properties and extensions.

194	2.  Interfaces Extensions Overview

196	   This document defines extensions for the CDNI Control Interface /
197	   Triggers (CI/T) [RFC8007] and defines FCI objects as per the CDNI
198	   Footprint and Capabilities Interface [RFC8008].

200	2.1.  CDNI Control Interface / Triggers Extensions

202	2.1.1.  CI/T Objects

204	   This document specifies version 2 of the CI/T commands and objects.
205	   In this context the CI/T commands and objects as were specified in
206	   [RFC8007] are considered to be version 1.

208	2.1.2.  Trigger Specification

210	   This document specifies version 2 of the Trigger Specification which
211	   is an enhancement of the Trigger Specification that includes all
212	   properties as defined in Section 5.2.1 of [RFC8007] as well as the
213	   additional properties required by the use cases listed below in
214	   Section 2.1.3 and Section 2.1.4.

216	2.1.3.  Content Selection

218	   The trigger specification as defined in Section 5.2.1 of [RFC8007]
219	   provides means to select content objects by matching a full content
220	   URL or patterns with wildcards.  This document specifies two
221	   additional selection options:

223	   o  Regular Expression - Using regex, a uCDN can create more complex
224	      rules to select the content objects for the cases of
225	      "invalidation" and "purge".  For example, purging specific content
226	      within a specific directory path.

228	   o  Content Playlist - Using video playlist files, a uCDN can trigger
229	      an operation that will be applied to a collection of distinct
230	      media files in a format that is natural for a streaming video
231	      content provider.  A playlist may have several formats,
232	      specifically HTTP Live Streaming (HLS) *.m3u8 manifest [RFC8216],
233	      Microsoft Smooth Streaming (MSS) *.ismc client manifest [MSS], and
234	      Dynamic Adaptive Streaming over HTTP (DASH) *.mpd file [ISO/IEC
235	      23009-1:2014] [MPEG-DASH].

237	2.1.4.  Trigger Extensibility

239	   The CDNI Control Interface / Triggers [RFC8007] defines a set of
240	   properties and objects used by the trigger commands.  In this
241	   document we define an extension mechanism to the triggers interface
242	   that enables the application to add various functions that allow
243	   finer control over the trigger execution.  This document specifies a
244	   generic trigger extension object wrapper for managing individual CDNI
245	   trigger extensions in an opaque manner.

247	   This document also registers CDNI Payload Types [RFC7736] under the
248	   namespace CIT for the initial set of trigger extension types:

250	   o  CIT.LocationPolicy (for controlling the locations in which the
251	      trigger is executed)

253	   o  CIT.TimePolicy (for scheduling a trigger to run in a specific time
254	      window)

256	   Example use cases

258	   o  Pre-position with cache location policy

260	   o  Purge content with cache location policy

262	   o  Pre-position at a specific time

264	   o  Purge by content acquisition time (e.g. purge all content acquired
265	      in the past X hours)

267	2.1.5.  Error Handling

269	   This document extends the CI/T Error Handling (see Section 4.7 of
270	   [RFC8007]) to support the following:

272	   o  Playlists and Regexs - report errors that happened due to specific
273	      playlists and/or regexs.

275	   o  Extension errors - report an error that happened due to an
276	      extension object.

278	   o  Error propagation - enable the uCDN to traceback an error to the
279	      dCDN in which it occurred.

281	2.2.  CDNI Footprint and Capabilities Interface Extensions

283	   Extending the trigger mechanism with optional properties requires the
284	   ability for the dCDN to advertise which optional properties it
285	   supports.

287	   The CDNI Footprint and Capabilities Interface [RFC8008] enables the
288	   dCDN to advertise the capabilities it supports across different
289	   footprints.  This document introduces FCI objects to support the
290	   advertisement of these optional properties.

292	   Example use cases

294	   o  Trigger types: Advertise which trigger types are supported by the
295	      dCDN.  CDNI defines three trigger types (purge, invalidate, pre-
296	      position), but it does not necessarily mean that all dCDNs support
297	      all of them.  The uCDN may prefer to work only with dCDN that
298	      support what the uCDN needs.

300	   o  Content selection rule types: Advertise which selection types are
301	      supported.  For example, if adding content regex as a means to
302	      match on content URLs, not all dCDN would support it.  For
303	      playlist mapping, advertise which types and versions of protocols
304	      are supported, e.g.  HLS.vX/DASH.vY/MSS.vX, DASH templates.  Note
305	      that the version string or schema are protocol specific.

307	   o  Trigger extensions: Advertise which trigger extensions object
308	      types are supported by the dCDN.

310	3.  CI/T Version 2

312	   [RFC8007] does not define a version number and versioning scheme.
313	   We, therefore, designate the interface and objects as defined in
314	   Section 5 of [RFC8007] as version 1.  The following sections define
315	   version 2 of the CI/T objects and their properties as extensions of
316	   version 1.

318	3.1.  CI/T Objects V2

320	   Version 2 of the CI/T interface requires the support of the following
321	   objects:

323	   o  CI/T Commands v2: A trigger command request using the payload type
324	      ci-trigger-command.v2.  Version 2 MUST only use "trigger.v2"
325	      objects as defined in Section 3.3.1, instead of "trigger" objects.
326	      All other properties of the trigger command v2 are as defined in
327	      Section 5.1.1 of [RFC8007].

329	   o  Trigger Status Resource v2: A trigger status resource response
330	      using the payload type ci-trigger-status.v2.  Version 2 MUST only
331	      use "trigger.v2" objects as defined in Section 3.3.1, instead of a
332	      "trigger" object, as well as "errors.v2" array as defined in
333	      Section 3.3.6, instead of a "errors" array.  All other properties
334	      of the trigger status v2 are as defined in Section 5.1.2 of
335	      [RFC8007].  The errors array "errors.v2" is a list of all errors
336	      that occurred in any of the downstream CDNs along the execution
337	      path.  When a downstream CDN, dCDN-A, propagates a trigger to
338	      another downstream CDN, dCDN-B, it MUST also propagate back all
339	      errors reported by dCDN-B in the trigger status resource and add
340	      them to its own trigger status resource.

342	   o  Trigger Collections: The payload type ci-trigger-collection is
343	      used with no changes and as defined in 5.1.3 of [RFC8007].

345	   Usage example of version 2 of trigger command
346	   REQUEST:

348	     POST /triggers HTTP/1.1
349	     User-Agent: example-user-agent/0.1
350	     Host: triggers.dcdn.example.com
351	     Accept: */*
352	     Content-Type: application/cdni; ptype=ci-trigger-command.v2
353	     {
354	       "trigger.v2": { <properties of a trigger.v2 object> },
355	       "cdn-path": [ "AS64496:0" ]
356	     }

358	   RESPONSE:

360	     HTTP/1.1 201 Created
361	     Date: Wed, 04 May 2016 08:48:10 GMT
362	     Content-Length: 467
363	     Content-Type: application/cdni; ptype=ci-trigger-status.v2
364	     Location: https://triggers.dcdn.example.com/triggers/0
365	     Server: example-server/0.1

367	     {
368	        "errors.v2": [ { <properties of 1st error.v2 object> },
369	                         ...,
370	                       { <properties of Nth error.v2 object> }
371	        ],
372	        "ctime": 1462351690,
373	        "etime": 1462351698,
374	        "mtime": 1462351690,
375	        "status": "pending",
376	        "trigger.v2": { <properties of a trigger.v2 object> }
377	     }

379	   Usage example of version 2 of trigger status for the trigger created
380	   in the above trigger command example:

382	   REQUEST:

384	     GET /triggers/0 HTTP/1.1
385	     User-Agent: example-user-agent/0.1
386	     Host: triggers.dcdn.example.com
387	     Accept: */*

389	   RESPONSE:

391	     HTTP/1.1 200 OK
392	     Content-Length: 467
393	     Expires: Wed, 04 May 2016 08:49:10 GMT
394	     Server: example-server/0.1
395	     ETag: "6990548174277557683"
396	     Cache-Control: max-age=60
397	     Date: Wed, 04 May 2016 08:48:10 GMT
398	     Content-Type: application/cdni; ptype=ci-trigger-status.v2

400	     {
401	        "errors.v2": [ { <properties of 1st error.v2 object> },
402	                         ...,
403	                       { <properties of Nth error.v2 object> }
404	        ],
405	        "ctime": 1462351690,
406	        "etime": 1462351698,
407	        "mtime": 1462351690,
408	        "status": "pending",
409	        "trigger.v2": { <properties of a trigger.v2 object> }
410	     }

412	3.2.  Error Handling V2

414	   The CDNI CI/T interface defines a mechanism for error reporting (see
415	   Section 4.7 of [RFC8007]) and an Error Description object for
416	   reporting errors (see Section 5.2.6 of [RFC8007]).  This document
417	   specifies version 2 of CI/T error handling in order to support the
418	   following:

420	3.2.1.  Extension Errors

422	   Report an error that occures due to an extension object.  As
423	   extension objects are expected to be added to the interface whenever
424	   new requirement comes along, it is expected that in some cases a dCDN
425	   may receive a trigger that it cannot process or it does not
426	   understand.  It is therefore essential for the trigger caller to be
427	   able to know when such errors occur so they can take actions to fix
428	   them.  This document adds a mechanism to report extension errors.

430	3.2.2.  Error propagation

432	   This subsection explains the mechanism for enabling the uCDN to
433	   traceback an error to the dCDN in which it occurred.  CDNI triggers
434	   may be propagated over a chain of downstream CDNs.  For example, an
435	   upstream CDN A (uCDN-A) that is delegating to a downstream CDN B
436	   (dCDN-B) and dCDN-B is delegating to a downstream CDN C (dCDN-C).
437	   Triggers sent from uCDN-A to dCDN-B may be redistributed from dCDN-B
438	   to dCDN-C and errors can occur anywhere along the path.  Therefore,
439	   it might be essential for uCDN-A that sets the trigger, to be able to
440	   trace back an error to the downstream CDN where it occurred.  This
441	   document adds a mechanism to propagate the CDN Provider ID (PID) of
442	   the dCDN where the fault occured, back to the uCDN by adding the PID
443	   to the error description.  When dCDN-B propagates a trigger to the
444	   further downstream dCDN-C, it MUST also propagate back the errors
445	   received in the trigger status resource from dCDN-C by adding them to
446	   the errors array in its own status resource to be sent back to the
447	   originating uCDN-A.  While propagating back the errors, and depending
448	   on the implementation, dCDN-B MAY also specify the dCDN-C PID,
449	   indicating to which CDN the error relates spefically.  The trigger
450	   originating upstream CDN will receive an array of errors that
451	   occurred in all the CDNs along the execution path, where each error
452	   MAY be carrying its own CDN identifier.

454	   Figure 1 below is an example showing the message flow used by uCDN-A
455	   to trigger activity in the dCDN-B, followed by dCDN-C, as well as the
456	   discovery of the status of that activity, including the Error
457	   Propagation.

459	   uCDN-A                         dCDN-B                         dCDN-C
460	    |                              |                              |
461	    | (1) POST                     |                              |
462	    | https://dcdn-b.example.com   |                              |
463	    | /triggers/uCDN-A             |                              |
464	   [ ]--------------------------->[ ]--+                          |
465	    |                             [ ]  | (2)                      |
466	    |                             [ ]<-+                          |
467	    | (3) HTTP 201 Response.      [ ]                             |
468	    |<----------------------------[ ]                             |
469	    | Loc:                        [ ]                             |
470	    | https://dcdn-b.example.com  [ ] (4) POST                    |
471	    | /triggers/uCDN-A/123        [ ] https://dcdn-c.example.com  |
472	    |                             [ ] /triggers/uCDN-A            | (5)
473	    |                             [ ]--------------------------->[ ]--+
474	    |                              |                             [ ]  |
475	    |                              |                             [ ]<-+
476	    |                              | (6) HTTP 201 Response.      [ ]
477	    |                             [ ]<---------------------------[ ]
478	    |                              |  Loc:                        |
479	    |                              |  https://dcdn-c.example.com  |
480	    |                              |  /triggers/dCDN-B/456        |
481	    |                              |                              |
482	    |                             [ ]--+                          |
483	    |                             [ ]  | (7.1)                    |
484	    |                             [ ]<-+                         [ ]--+
485	    |                              |                       (7.2) [ ]  |
486	    |                              |                             [ ]<-+
487	    |                              |                              |
488	    .                              .                              .
489	    .                              .                              .
490	    .                              .                              .
491	    |                              | (8) GET                      |
492	    |                              | https://dcdn-c.example.com   |
493	    |                              | /triggers/dCDN-B/456         |
494	    |                             [ ]--------------------------->[ ]
495	    |                              |                             [ ]
496	    |                              | (9) HTTP 200                [ ]
497	    |                              | Trigger Status Resource     [ ]
498	    |                             [ ]<---------------------------[ ]
499	    |                              |                              |
500	    .                              .                              .
501	    .                              .                              .
502	    .                              .                              .
503	    | (10) GET                     |                              |
504	    | https://dcdn-b.example.com   |                              |
505	    | /triggers/uCDN-A/123         |                              |
506	   [ ]--------------------------->[ ]                             |
507	    |                             [ ]                             |
508	    | (11) HTTP 200               [ ]                             |
509	    | Trigger Status Resource     [ ]                             |
510	   [ ]<---------------------------[ ]                             |

512	   Figure 1: CDNI Message Flow for Triggers, Including Error Propagation

514	   The steps in Figure 1 are as follows:

516	   1.   The uCDN-A triggers action in the dCDN-B by POSTing a CI/T
517	        Command to a collection of Trigger Status Resources
518	        "https://dcdn-b.example.com/triggers/uCDN-A".  This URL was
519	        given to the uCDN-A when the CI/T interface was established.

521	   2.   The dCDN-B authenticates the request, validates the CI/T
522	        Command, and, if it accepts the request, creates a new Trigger
523	        Status Resource.

525	   3.   The dCDN-B responds to the uCDN-A with an HTTP 201 response
526	        status and the location of the Trigger Status Resource.

528	   4.   The dCDN-B triggers the action in the dCDN-C by POSTing a CI/T
529	        Command to a collection of Trigger Status Resources
530	        "https://dcdn-c.example.com/triggers/dCDN-B".  This URL was
531	        given to the uCDN-A when the CI/T interface was established.

533	   5.   The dCDN-C authenticates the request, validates the CI/T
534	        Command, and, if it accepts the request, creates a new Trigger
535	        Status Resource.

537	   6.   The dCDN-C responds to the dCDN-B with an HTTP 201 response
538	        status and the location of the Trigger Status Resource.

540	   7.   The dCDN-C acts upon the CI/T Command.  However, the command
541	        fails at dCDN-C as, for example, the Tigger Specification
542	        contains a "type" that is not supported by dCDN-C.

544	   8.   The dCDN-B can poll, possibly repeatedly, the Trigger Status
545	        Resource in dCDN-C.

547	   9.   The dCDN-C responds with the Trigger Status Resource, describing
548	        the progress or results of the CI/T Trigger Command.  In the
549	        described flow, the returned Status is "failed", with an Error
550	        Description Object holding an "eunsupported" Error Code
551	        reflecting the status response.

553	   10.  The uCDN-A can poll, possibly repeatedly, the Trigger Status
554	        Resource in dCDN-B.

556	   11.  The dCDN-B responds with the Trigger Status Resource, describing
557	        the progress or results of the CI/T Trigger Command.  In the
558	        flow described above, the returned Status is "failed", and the
559	        "eunsupported" error received in the trigger status resource
560	        from dCDN-C is propagated along with dCDN-C PID by adding it to
561	        the errors array in dCDN-B's own status resource to be sent back
562	        to the originating uCDN-A.

564	3.3.  Properties of CI/T Version 2 objects

566	   This section defines the values that can appear in the top-level
567	   objects described in Section 3.1, and their encodings.

569	3.3.1.  Trigger Specification Version 2

571	   Version 2 of the Trigger Specification adds the following properties
572	   on top of the existing properties of the trigger specification
573	   defined in Section 5.2.1 of [RFC8007].

575	      Property: content.regexs

577	         Description: Regexs of content URLs to which the CI/T trigger
578	         command applies.

580	         Type: A JSON array of RegexMatch objects (see Section 3.3.2).

582	         Mandatory: No, but at least one of "metadata.*" or "content.*"
583	         MUST be present and non-empty.

585	      Property: content.playlists

587	         Description: Playlists of content the CI/T trigger command
588	         applies to.

590	         Type: A JSON array of Playlist objects (see Section 3.3.3).

592	         Mandatory: No, but at least one of "metadata.*" or "content.*"
593	         MUST be present and non-empty.

595	      Property: extensions

597	         Description: Array of trigger extension data.

599	         Type: Array of GenericTriggerExtension objects (see
600	         Section 3.3.5.2).

602	         Mandatory: No.  The default is no extensions.

604	   Example of a JSON serialized invalidation trigger.v2 object with a
605	   list of regex objects, a list of playlist objects, and extensions:

607	   {
608	     "trigger.v2": {
609	       "type": "invalidate",
610	       "content.regexs": [ <list of RegexMatch objects> ],
611	       "content.playlists": [ <list of Playlist objects> ],
612	       "extensions": [ <list of GenericTriggerExtension objects ]
613	     },
614	     "cdn-path": [ "AS64496:0" ]
615	   }

617	3.3.2.  RegexMatch

619	   A RegexMatch consists of a regular expression string a URI is matched
620	   against, and flags describing the type of match.  It is encoded as a
621	   JSON object with following properties:

623	      Property: regex

625	         Description: A regular expression for URI matching.

627	         Type: A regular expression to match against the URI, i.e
628	         against the path-absolute and the query string parameters
629	         [RFC3986].  The regular expression string MUST be compatible
630	         with PCRE [PCRE841].

632	         Note: Because '\' has a special meaning in JSON [RFC8259] as
633	         the escape character within JSON strings, the regular
634	         expression character '\' MUST be escaped as '\\'.

636	         Mandatory: Yes.

638	      Property: case-sensitive

640	         Description: Flag indicating whether or not case-sensitive
641	         matching should be used.

643	         Type: JSON boolean.  Either "true" (the matching is case
644	         sensitive) or "false" (the matching is case insensitive).

646	         Mandatory: No; default is case-insensitive match (i.e., a value
647	         of "false").

649	      Property: match-query-string

651	         Description: Flag indicating whether to include the query part
652	         of the URI when comparing against the regex.

654	         Type: JSON boolean.  Either "true" (the full URI, including the
655	         query part, should be compared against the regex) or "false"
656	         (the query part of the URI should be dropped before comparison
657	         with the given regex).

659	         Mandatory: No; default is "false".  The query part of the URI
660	         MUST be dropped before comparison with the given regex.  This
661	         makes the regular expression simpler and safer for cases in
662	         which the query parameters are not relevant for the match.

664	   Example of a case sensitive, no query parameters, regex match
665	   against:

667	   "^(https:\/\/video\.example\.com)\/([a-z])\/
668	    movie1\/([1-7])\/*(index.m3u8|\d{3}.ts)$"

670	   {
671	     "regex": "^(https:\\/\\/video\\.example\\.com)\\/([a-z])\\/movie1\
672	              \/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
673	     "case-sensitive": true,
674	     "match-query-string": false
675	   }

677	   This regex matches URLs of domain video.example.com where the path
678	   structure is /(single lower case letter)/(name-of-title)/(single
679	   digit between 1 to 7)/(index.m3u8 or a 3 digit number with ts
680	   extension).  For example:

682	   https://video.example.com/d/movie1/5/index.m3u8
683	   or
684	   https://video.example.com/k/movie1/4/013.ts

686	3.3.3.  Playlist

688	   A Playlist consists of a full URL and a media protocol identifier.
689	   An implementation that supports a specific playlist media protocol
690	   MUST be able to parse playlist files of that protocol type and
691	   extract, possibly recursively, the URLs to all media objects and/or
692	   sub playlist files, and apply the trigger to each one of them
693	   separately.

695	   Playlist is encoded as a JSON object with following properties:

697	      Property: playlist

699	         Description: A URL to the playlist file.

701	         Type: A URL represented as a JSON string.

703	         Mandatory: Yes.

705	      Property: media-protocol

707	         Description: Media protocol to be when parsing and interpreting
708	         this playlist.

710	         Type: MediaProtocol (see Section 3.3.4).

712	         Mandatory: Yes.

714	   Example of a JSON serialized HLS playlist object:

716	   {
717	     "playlist": "https://www.example.com/hls/title/index.m3u8",
718	     "media-protocol": "hls"
719	   }

721	3.3.4.  MediaProtocol

723	   Media Protocol objects are used to specify registered type of media
724	   protocol (see Section 6.3) used for protocol related operations like
725	   pre-position according to playlist.

727	   Type: JSON string

729	   Example:

731	   "dash"

733	3.3.5.  CI/T Trigger Extensions

735	   A "trigger.v2" object, as defined in Section 3.3.1 includes an
736	   optional array of trigger extension objects.  A trigger extension
737	   contain properties that are used as directives for dCDN when
738	   executing the trigger command -- for example, location policies, time
739	   policies and so on.  Each such CDNI Trigger extension is a
740	   specialization of a CDNI GenericTriggerExtension object.  The
741	   GenericTriggerExtension object abstracts the basic information
742	   required for trigger distribution from the specifics of any given
743	   property (i.e., property semantics, enforcement options, etc.).  All
744	   trigger extensions are optional, and it is thus the responsibility of
745	   the extension specification to define a consistent default behavior
746	   for the case the extension is not present.

748	3.3.5.1.  Enforcement Options

750	   The trigger enforcement options concept is in accordance with the
751	   metadata enforcement options as defined in Section 3.2 of [RFC8006].

753	   The GenericTriggerExtension object defines the properties contained
754	   within it as well as whether or not the properties are "mandatory-to-
755	   enforce".  If the dCDN does not understand or support a mandatory-to-
756	   enforce property, the dCDN MUST NOT execute the trigger command.  If
757	   the extension is not mandatory-to-enforce, then that
758	   GenericTriggerExtension object can be safely ignored and the trigger
759	   command can be processed in accordance with the rest of the CDNI
760	   Trigger spec.

762	   Although, a CDN MUST NOT execute a trigger command if a mandatory-to-
763	   enforce extension cannot be enforced, it could still be safe to
764	   redistribute that trigger (the "safe-to-redistribute" property) to
765	   another CDN without modification.  For example, in the cascaded CDN
766	   case, a transit CDN (tCDN) could convey mandatory-to-enforce trigger
767	   extension to a dCDN.  For a trigger extension that does not require
768	   customization or translation (i.e., trigger extension that is safe-
769	   to-redistribute), the data representation received off the wire MAY
770	   be stored and redistributed without being understood or supported by
771	   the tCDN.  However, for trigger extension that requires translation,
772	   transparent redistribution of the uCDN trigger values might not be
773	   appropriate.  Certain triggers extensions can be safely, though
774	   perhaps not optimally, redistributed unmodified.  For example, pre-
775	   position command might be executed in suboptimal times for some
776	   geographies if transparently redistributed, but it might still work.

778	   Redistribution safety MUST be specified for each
779	   GenericTriggerExtension property.  If a CDN does not understand or
780	   support a given GenericTriggerExtension property that is not safe-to-
781	   redistribute, the CDN MUST set the "incomprehensible" flag to true
782	   for that GenericTriggerExtension object before redistributing it.
783	   The "incomprehensible" flag signals to a dCDN that trigger metadata
784	   was not properly transformed by the tCDN.  A CDN MUST NOT attempt to
785	   execute a trigger with an extension that has been marked as
786	   "incomprehensible" by a uCDN.

788	   tCDNs MUST NOT change the value of mandatory-to-enforce or safe-to-
789	   redistribute when propagating a trigger to a dCDN.  Although a tCDN
790	   can set the value of "incomprehensible" to true, a tCDN MUST NOT
791	   change the value of "incomprehensible" from true to false.

793	   Table 1 describes the action to be taken by a tCDN for the different
794	   combinations of mandatory-to-enforce ("MtE") and safe-to-redistribute
795	   ("StR") properties when the tCDN either does or does not understand
796	   the trigger extension object in question:

798	   +-------+-------+------------+--------------------------------------+
799	   | MtE   | StR   | Extension  | Trigger action                       |
800	   |       |       | object     |                                      |
801	   |       |       | understood |                                      |
802	   |       |       | by tCDN    |                                      |
803	   +-------+-------+------------+--------------------------------------+
804	   | False | True  | True       | Can execute and redistribute.        |
805	   | False | True  | False      | Can execute and redistribute.        |
806	   | False | False | False      | Can execute. MUST set                |
807	   |       |       |            | "incomprehensible" to true when      |
808	   |       |       |            | redistributing.                      |
809	   | False | False | True       | Can execute. Can redistribute after  |
810	   |       |       |            | transforming the trigger extension   |
811	   |       |       |            | (if the CDN knows how to do so       |
812	   |       |       |            | safely); otherwise, MUST set         |
813	   |       |       |            | "incomprehensible" to true when      |
814	   |       |       |            | redistributing.                      |
815	   | True  | True  | True       | Can execute and redistribute.        |
816	   | True  | True  | False      | MUST NOT execute but can             |
817	   |       |       |            | redistribute..                       |
818	   | True  | False | True       | Can execute. Can redistribute after  |
819	   |       |       |            | transforming the trigger extension   |
820	   |       |       |            | (if the CDN knows how to do so       |
821	   |       |       |            | safely); otherwise, MUST set         |
822	   |       |       |            | "incomprehensible" to true when      |
823	   |       |       |            | redistributing.                      |
824	   | True  | False | False      | MUST NOT serve.  MUST set            |
825	   |       |       |            | "incomprehensible" to true when      |
826	   |       |       |            | redistributing.                      |
827	   +-------+-------+------------+--------------------------------------+

829	   Table 1: Action to be taken by a tCDN for the different combinations
830	                         of MtE and StR properties

832	   Table 2 describes the action to be taken by a dCDN for the different
833	   combinations of mandatory-to-enforce and "incomprehensible"
834	   ("Incomp") properties, when the dCDN either does or does not
835	   understand the trigger extension object in question:

837	   +-------+--------+---------------+----------------------------------+
838	   | MtE   | Incomp | Extension     | Trigger action                   |
839	   |       |        | object        |                                  |
840	   |       |        | understood by |                                  |
841	   |       |        | dCDN          |                                  |
842	   +-------+--------+---------------+----------------------------------+
843	   | False | False  | True          | Can execute.                     |
844	   | False | True   | True          | Can execute but MUST NOT         |
845	   |       |        |               | interpret/apply any trigger      |
846	   |       |        |               | extension marked as              |
847	   |       |        |               | "incomprehensible".              |
848	   | False | False  | False         | Can execute.                     |
849	   | False | True   | False         | Can execute but MUST NOT         |
850	   |       |        |               | interpret/apply any trigger      |
851	   |       |        |               | extension marked as              |
852	   |       |        |               | "incomprehensible".              |
853	   | True  | False  | True          | Can execute.                     |
854	   | True  | True   | True          | MUST NOT execute.                |
855	   | True  | False  | False         | MUST NOT execute.                |
856	   | True  | True   | False         | MUST NOT execute.                |
857	   +-------+--------+---------------+----------------------------------+

859	   Table 2: Action to be taken by a dCDN for the different combinations
860	                       of MtE and Incomp properties

862	3.3.5.2.  GenericExtensionObject

864	   A GenericTriggerExtension object is a wrapper for managing individual
865	   CDNI Trigger extensions in an opaque manner.

867	      Property: generic-trigger-extension-type

869	         Description: Case-insensitive CDNI Trigger extension object
870	         type.

872	         Type: String containing the CDNI Payload Type [RFC7736] of the
873	         object contained in the generic-trigger-extension-value
874	         property (see table in Section 6.1).

876	         Mandatory: Yes.

878	      Property: generic-trigger-extension-value

880	         Description: CDNI Trigger extension object.

882	         Type: Format/Type is defined by the value of the generic-
883	         trigger-extension-type property above.

885	         Mandatory: Yes.

887	      Property: mandatory-to-enforce

889	         Description: Flag identifying whether or not the enforcement of
890	         this trigger extension is mandatory.

892	         Type: Boolean

894	         Mandatory: No.  Default is to treat the trigger extension as
895	         mandatory-to-enforce (i.e., a value of True).

897	      Property: safe-to-redistribute

899	         Description: Flag identifying whether or not this trigger
900	         extension can be safely redistributed without modification,
901	         even if the CDN fails to understand the extension.

903	         Type: Boolean

905	         Mandatory: No.  Default is to allow transparent redistribution
906	         (i.e., a value of True).

908	      Property: incomprehensible

910	         Description: Flag identifying whether or not any CDN in the
911	         chain of delegation has failed to understand and/or failed to
912	         properly transform this trigger extension object.  Note: This
913	         flag only applies to trigger extension objects whose safe-to-
914	         redistribute property has a value of False.

916	         Type: Boolean

918	         Mandatory: No.  Default is comprehensible (i.e., a value of
919	         False).

921	   Example of a JSON serialized GenericTriggerExtension object
922	   containing a specific trigger extension object:

924	   {
925	     "generic-trigger-extension-type":
926	        <Type of this trigger extension object>,
927	     "generic-trigger-extension-value":
928	         {
929	           <properties of this trigger extension object>
930	         },
931	     "mandatory-to-enforce": true,
932	     "safe-to-redistribute": true,
933	     "incomprehensible": false
934	   }

936	3.3.6.  Error Description Version 2

938	   Version 2 of the Error Description adds the "content.playlists",
939	   "content.regexs", "extensions" and "cdn" properties on top of the
940	   existing properties of version 1 of the trigger Error Description as
941	   defined in Section 5.2.6 of [RFC8007].

943	      Properties: content.regexs, content.playlists

945	         Description: Content Regex and Playlist references copied from
946	         the Trigger Specification.  Only those regexs and playlists to
947	         which the error applies are included in each property, but
948	         those references MUST be exactly as they appear in the request;
949	         the dCDN MUST NOT change or generalize the URLs or Regexs.
950	         Note that these properties are added on top of the already
951	         existing properties: "metadata.urls", "content.urls",
952	         "metadata.patterns" and "content.patterns".

954	         Type: A JSON array of JSON strings, where each string is copied
955	         from a "content.regexs" or "content.playlists" value in the
956	         corresponding Trigger Specification.

958	         Mandatory: At least one of "content.regexs",
959	         "content.playlists", "metadata.urls", "content.urls",
960	         "metadata.patterns" or "content.patterns" is mandatory in each
961	         Error Description object.

963	      Property: extensions

965	         Description: Array of trigger extension objects copied from the
966	         corresponding "extensions" array from the Trigger
967	         Specification.  Only those extensions to which the error
968	         applies are included, but those extensions MUST be exactly as
969	         they appear in the request.

971	         Type: Array of GenericTriggerExtension objects, where each
972	         extension object is copied from the "extensions" array values
973	         in the Trigger Specification.

975	         Mandatory: No.  The "extensions" array SHOULD be used only if
976	         the error relates to extension objects.

978	      Property: cdn

980	         Description: The CDN PID of the CDN where the error occurred.
981	         The "cdn" property is used by the originating uCDN or by
982	         propagating dCDN in order to distinguish in which CDN the error
983	         occured.

985	         Type: A non-empty JSON string, where the string is a CDN PID as
986	         defined in Section 4.6 of [RFC8007].

988	         Mandatory: Yes. In the case the dCDN does not like to expose
989	         this information, it should provide its own CDN PID.

991	   Example of a JSON serialized Error Description object reporting a
992	   malformed Playlist:

994	   {
995	      "content.playlists": [
996	         {
997	           "playlist": "https://www.example.com/hls/title/index.m3u8",
998	           "media-protocol": "hls"
999	         }
1000	       ],
1001	      "description": "Failed to parse HLS playlist",
1002	      "error": "econtent",
1003	      "cdn": "AS64500:0"
1004	   },

1006	   Example of a JSON serialized Error Description object reporting an
1007	   unsupported extension object:

1009	   {
1010	     "errors.v2": [
1011	      {
1012	        "extensions": [
1013	          {
1014	           "generic-trigger-extension-type":
1015	             <Type of this erroneous trigger extension object>,
1016	           "generic-trigger-extension-value":
1017	             {
1018	              <properties of this erroneous trigger extension object>
1019	             },
1020	          }
1021	        ],
1022	        "description": "unrecognized extension <type>",
1023	        "error": "eextension",
1024	        "cdn": "AS64500:0"
1025	      },
1026	     ]
1027	   }

1029	3.3.7.  Error codes

1031	   This document adds the error code "eextension" to the error codes
1032	   table defined in Section 5.2.6 of [RFC8007].  This error code
1033	   designates that an error occurred while parsing a generic trigger
1034	   extension, or that the specific extension is not supported by the
1035	   CDN.  A CDN that fails to execute a trigger due a generic extension
1036	   object which is "mandatory-to-enforce" MUST report it using the
1037	   "errors.v2" array within the trigger status resource, while setting
1038	   the error code to "eextension" and providing an appropriate
1039	   description.  The "eextension" error code is a registered type of
1040	   "CDNI CI/T Trigger Error Codes" (see Section 6.2).

1042	3.4.  Examples

1044	   The following subsections provides usage examples of the specified
1045	   interface extensions being used by the trigger command and status
1046	   resource.

1048	3.4.1.  Invalidation with Regex

1050	   In the following example a CI/T "invalidate" command uses the Regex
1051	   property to specify the range of content objects for invalidation,
1052	   the command is rejected by the dCDN due to regex complexity, and an
1053	   appropriate error is reflected in the status response.

1055	   REQUEST:

1057	     POST /triggers HTTP/1.1
1058	     User-Agent: example-user-agent/0.1
1059	     Host: triggers.dcdn.example.com
1060	     Accept: */*
1061	     Content-Type: application/cdni; ptype=ci-trigger-command.v2
1062	     {
1063	       "trigger.v2": {
1064	         "type": "invalidate",
1065	         "content.regexs": [
1066	           {
1067	             "regex": "^(https:\\/\\/video\\.example\\.com)\\/
1068	             ([a-z])\\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
1069	             "case-sensitive": true,
1070	             "match-query-string": false
1071	           },
1072	           { <RegexMatch #2> },
1073	           ...
1074	           { <RegexMatch #N> },
1075	         ],
1076	       },
1077	       "cdn-path": [ "AS64496:0" ]
1078	     }

1080	   RESPONSE:

1082	     HTTP/1.1 201 Created
1083	     Date: Wed, 04 May 2016 08:48:10 GMT
1084	     Content-Length: 467
1085	     Content-Type: application/cdni; ptype=ci-trigger-status.v2
1086	     Location: https://triggers.dcdn.example.com/triggers/0
1087	     Server: example-server/0.1

1089	     {
1090	       "errors.v2": [
1091	         {
1092	           "content.regexs": [
1093	             {
1094	               "regex": "^(https:\\/\\/video\\.example\\.com)\\/
1095	               ([a-z])\\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
1096	               "case-sensitive": true,
1097	               "match-query-string": false
1098	             },
1099	           ],
1100	           "description": "The dCDN rejected a regex due to complexity",
1101	           "error": "ereject",
1102	           "cdn": "AS64500:0"
1103	         },
1104	       ],
1105	       "ctime": 1462351690,
1106	       "etime": 1462351698,
1107	       "mtime": 1462351690,
1108	       "status": "failed",
1109	       "trigger.v2": { <content of trigger object from the command> }
1110	     }

1112	3.4.2.  Preposition with Playlists

1114	   In the following example a CI/T "preposition" command uses the
1115	   Playlist property to specify the full media library of a specific
1116	   content.  The command fails due to playlist parse error and an
1117	   appropriate error is reflected in the status response.

1119	   REQUEST:

1121	     POST /triggers HTTP/1.1
1122	     User-Agent: example-user-agent/0.1
1123	     Host: triggers.dcdn.example.com
1124	     Accept: */*
1125	     Content-Type: application/cdni; ptype=ci-trigger-command.v2
1126	     {
1127	       "trigger.v2": {
1128	         "type": "preposition",
1129	         "content.playlists": [
1130	          {
1131	           "playlist": "https://www.example.com/hls/title/index.m3u8",
1132	           "media-protocol": "hls"
1133	          },
1134	          { <Playlist #2> },
1135	          ...
1136	          { <Playlist #N> },
1137	         ],
1138	       },
1139	       "cdn-path": [ "AS64496:0" ]
1140	     }

1142	   RESPONSE:

1144	     HTTP/1.1 201 Created
1145	     Date: Wed, 04 May 2016 08:48:10 GMT
1146	     Content-Length: 467
1147	     Content-Type: application/cdni; ptype=ci-trigger-status.v2
1148	     Location: https://triggers.dcdn.example.com/triggers/0
1149	     Server: example-server/0.1

1151	     {
1152	       "errors.v2": [
1153	         {
1154	          "content.playlists": [
1155	            {
1156	             "playlist": "https://www.example.com/hls/title/index.m3u8",
1157	             "media-protocol": "hls"
1158	            },
1159	           ],
1160	          "description": "The dCDN was not able to parse the playlist",
1161	          "error": "econtent",
1162	          "cdn": "AS64500:0"
1163	         },
1164	       ],
1165	       "ctime": 1462351690,
1166	       "etime": 1462351698,
1167	       "mtime": 1462351690,
1168	       "status": "failed",
1169	       "trigger.v2": { <content of trigger object from the command> }
1170	     }

1172	3.4.3.  Extensions with Error Propagation

1174	   In the following example a CI/T "preposition" command is using two
1175	   extensions to control the way the trigger is executed.  In this
1176	   example the receiving dCDN identified as "AS64500:0" does not support
1177	   the first extension in the extensions array. dCDN "AS64500:0" further
1178	   distributes this trigger to another downstream CDN that is identified
1179	   as "AS64501:0", which does not support the second extension in the
1180	   extensions array.  The error is propagated from "AS64501:0" to
1181	   "AS64500:0" and the errors.v2 array reflects both errors.

1183	   REQUEST:

1185	     POST /triggers HTTP/1.1
1186	     User-Agent: example-user-agent/0.1
1187	     Host: triggers.dcdn.example.com
1188	     Accept: */*
1189	     Content-Type: application/cdni; ptype=ci-trigger-command.v2
1190	     {
1191	       "trigger.v2": {
1192	         "type": "preposition",
1193	         "content.playlists": [
1194	          {
1195	            "playlist": "https://www.example.com/hls/title/index.m3u8",
1196	            "media-protocol": "hls"
1197	          },
1198	         ],
1199	         "extensions": [
1200	             {
1201	               "generic-trigger-extension-type":
1202	                  <Type of trigger extension object #1>,
1203	               "generic-trigger-extension-value":
1204	                   {
1205	                     <properties of trigger extension object #1>
1206	                   },
1207	               "mandatory-to-enforce": true,
1208	               "safe-to-redistribute": true,
1209	             },
1210	             {
1211	               "generic-trigger-extension-type":
1212	                  <Type of trigger extension object #2>,
1213	               "generic-trigger-extension-value":
1214	                   {
1215	                     <properties of trigger extension object #2>
1216	                   },
1217	               "mandatory-to-enforce": true,
1218	               "safe-to-redistribute": true,
1219	             },
1220	         ],
1221	       },
1222	       "cdn-path": [ "AS64496:0" ]
1223	     }

1225	   RESPONSE:

1227	     HTTP/1.1 201 Created
1228	     Date: Wed, 04 May 2016 08:48:10 GMT
1229	     Content-Length: 467
1230	     Content-Type: application/cdni; ptype=ci-trigger-status.v2
1231	     Location: https://triggers.dcdn.example.com/triggers/0
1232	     Server: example-server/0.1

1234	     {
1235	        "errors.v2": [
1236	          {
1237	            "extensions": [
1238	               {
1239	                 "generic-trigger-extension-type":
1240	                    <Type of trigger extension object #1>,
1241	                 "generic-trigger-extension-value":
1242	                     {
1243	                       <properties of trigger extension object #1>
1244	                     },
1245	                 "mandatory-to-enforce": true,
1246	                 "safe-to-redistribute": true,
1247	               },
1248	             ],

1250	            "description": "unrecognized extension <type>",
1251	            "error": "eextension",
1252	            "cdn": "AS64500:0"
1253	          },
1254	          {
1255	            "extensions": [
1256	               {
1257	                 "generic-trigger-extension-type":
1258	                    <Type of trigger extension object #2>,
1259	                 "generic-trigger-extension-value":
1260	                     {
1261	                       <properties of trigger extension object #2>
1262	                     },
1263	                 "mandatory-to-enforce": true,
1264	                 "safe-to-redistribute": true,
1265	               },
1266	             ],
1267	            "description": "unrecognized extension <type>",
1268	            "error": "eextension",
1269	            "cdn": "AS64501:0"
1270	          },
1271	        ],
1272	        "ctime": 1462351690,
1273	        "etime": 1462351698,
1274	        "mtime": 1462351690,
1275	        "status": "failed",
1276	        "trigger.v2": { <content of trigger object from the command> }
1277	     }

1279	4.  Trigger Extension Objects

1281	   The objects defined below are intended to be used in the
1282	   GenericTriggerExtension object's generic-trigger-extension-value
1283	   field as defined in Section Section 3.3.5.2, and their generic-
1284	   trigger-extension-type property MUST be set to the appropriate CDNI
1285	   Payload Type as defined in Section 6.1 .

1287	4.1.  LocationPolicy extension

1289	   A content operation may be relevant for a specific geographical
1290	   region, or need to be excluded from a specific region.  In this case,
1291	   the trigger should be applied only to parts of the network that are
1292	   either "included" or "not excluded" by the location policy.  Note
1293	   that the restrictions here are on the cache location rather than the
1294	   client location.

1296	   The LocationPolicy object defines which CDN or cache locations for
1297	   which the trigger command is relevant.

1299	   Example use cases:

1301	   o  Pre-position: Certain contracts allow for pre-positioning or
1302	      availability of contract in all regions except for certain
1303	      excluded regions in the world, including caches.  For example,
1304	      some content cannot ever knowingly touch servers in a specific
1305	      country, including cached content.  Therefore, these regions MUST
1306	      be excluded from a pre-positioning operation.

1308	   o  Purge: In certain cases, content may have been located on servers
1309	      in regions where the content must not reside.  In such cases, a
1310	      purge operation to remove content specifically from that region,
1311	      is required.

1313	   Object specification

1315	      Property: locations

1317	         Description: An Access List that allows or denies (blocks) the
1318	         trigger execution per cache location.

1320	         Type: Array of LocationRule objects (see Section 4.2.2.1 of
1321	         [RFC8006])

1323	         Mandatory: Yes.

1325	   If a location policy object is not listed within the trigger command,
1326	   the default behavior is to execute the trigger in all available
1327	   caches and locations of the dCDN.

1329	   The trigger command is allowed, or denied, for a specific cache
1330	   location according to the action of the first location whose
1331	   footprint matches against that cache's location.  If two or more
1332	   footprints overlap, the first footprint that matches against the
1333	   cache's location determines the action a CDN MUST take.  If the
1334	   "locations" property is an empty list or if none of the listed
1335	   footprints match the location of a specific cache location, then the
1336	   result is equivalent to a "deny" action.

1338	   The following is an example of a JSON serialized generic trigger
1339	   extension object containing a location policy object that allows the
1340	   trigger execution in the US but blocks its execution in Canada:

1342	   {
1343	      "generic-trigger-extension-type": "CIT.LocationPolicy",
1344	      "generic-trigger-extension-value":
1345	       {
1346	          "locations": [
1347	            {
1348	              "action": "allow",
1349	              "footprints": [
1350	                {
1351	                  "footprint-type": "countrycode",
1352	                  "footprint-value": ["us"]
1353	                }
1354	              ]
1355	            },
1356	            {
1357	              "action": "deny",
1358	              "footprints": [
1359	                {
1360	                  "footprint-type": "countrycode",
1361	                  "footprint-value": ["ca"]
1362	                }
1363	              ]
1364	            }
1365	          ]
1366	       },
1367	      "mandatory-to-enforce": true,
1368	      "safe-to-redistribute": true,
1369	      "incomprehensible": false
1370	   }

1372	4.2.  TimePolicy Extension

1374	   A uCDN may wish to perform content management operations on the dCDN
1375	   in a specific schedule.  The TimePolicy extensions allows the uCDN to
1376	   instruct the dCDN to execute the trigger command in a desired time
1377	   window.  For example, a content provider that wishes to pre-populate
1378	   a new episode at off-peak time so that it would be ready on caches at
1379	   prime time when the episode is released for viewing.  A scheduled
1380	   operation enables the uCDN to direct the dCDN in what time frame to
1381	   execute the trigger.

1383	   A uCDN may wish to to schedule a trigger such that the dCDN will
1384	   execute it in local time, as it is measured in each region.  For
1385	   example, a uCDN may wish the dCDN to pull the content at off-peak
1386	   hours, between 2AM-4AM, however, as a CDN is distributed across
1387	   multiple time zones, the UTC definition of 2AM depends on the actual
1388	   location.

1390	   We define two alternatives for localized scheduling:

1392	   o  Regional schedule: When used in conjunction with the Location
1393	      Policy defined in Section 4.1, the uCDN can trigger separate
1394	      commands for different geographical regions, for each region using
1395	      a different schedule.  This allows the uCDN to control the
1396	      execution time per region.

1398	   o  Local Time schedule: We introduce a "local time" version for
1399	      Internet timestamps that follows the notation for local time as
1400	      defined in Section 4.2.2 of [ISO8601].  When local time is used,
1401	      that dCDN SHOULD execute the triggers at different absolute times,
1402	      according the local time of each execution location.

1404	   Object specification

1406	      Property: unix-time-window

1408	         Description: A UNIX epoch time window in which the trigger
1409	         SHOULD be executed.

1411	         Type: TimeWindow object using UNIX epoch timestamps (see
1412	         Section 4.2.3.2 of [RFC8006])

1414	         Mandatory: No, but exactly one of "unixEpochWindow",
1415	         "utcWindow" or "localTimeWindow" MUST be present.

1417	      Property: utc-window

1419	         Description: A UTC time window in which the trigger SHOULD be
1420	         executed.

1422	         Type: UTCWindow object as defined in Section 4.2.1.

1424	         Mandatory: No, but exactly one of "unixEpochWindow",
1425	         "utcWindow" or "localTimeWindow" MUST be present.

1427	      Property: local-time-window

1429	         Description: A local time window.  The dCDN SHOULD execute the
1430	         trigger at the defined time frame, interpreted as the the local
1431	         time per location.

1433	         Type: LocalTimeWindow object as defined in Section 4.2.2.

1435	         Mandatory: No, but exactly one of "unixEpochWindow",
1436	         "utcWindow" or "localTimeWindow" MUST be present.

1438	   If a time policy object is not listed within the trigger command, the
1439	   default behavior is to execute the trigger in a time frame most
1440	   suitable to the dCDN taking under consideration other constrains and
1441	   / or obligations.

1443	   Example of a JSON serialized generic trigger extension object
1444	   containing a time policy object that schedules the trigger execution
1445	   to a window between 09:00 01/01/2000 UTC and 17:00 01/01/2000 UTC,
1446	   using the "unix-time-window" property:

1448	   {
1449	      "generic-trigger-extension-type": "CIT.TimePolicy",
1450	      "generic-trigger-extension-value":
1451	       {
1452	         "unix-time-window": {
1453	            "start": 946717200,
1454	            "end": 946746000
1455	         }
1456	       }
1457	      "mandatory-to-enforce": true,
1458	      "safe-to-redistribute": true,
1459	      "incomprehensible": false
1460	   }

1462	4.2.1.  UTCWindow

1464	   A UTCWindow object describes a time range in UTC or UTC and a zone
1465	   offset that can be applied by a TimePolicy.

1467	      Property: start

1469	         Description: The start time of the window.

1471	         Type: Internet date and time as defined in [RFC3339].

1473	         Mandatory: No, but at least one of "start" or "end" MUST be
1474	         present and non-empty.

1476	      Property: end

1478	         Description: The end time of the window.

1480	         Type: Internet date and time as defined in [RFC3339].

1482	         Mandatory: No, but at least one of "start" or "end" MUST be
1483	         present and non-empty.

1485	   Example JSON serialized UTCWindow object that describes a time window
1486	   from 02:30 01/01/2000 UTC to 04:30 01/01/2000 UTC:

1488	   {
1489	     "start": 2000-01-01T02:30:00.00Z,
1490	     "end": 2000-01-01T04:30:00.00Z,
1491	   }

1493	   Example JSON serialized UTCWindow object that describes a time window
1494	   in New York time zone offset UTC-05:00 from 02:30 01/01/2000 to 04:30
1495	   01/01/2000:

1497	   {
1498	     "start": 2000-01-01T02:30:00.00-05:00,
1499	     "end": 2000-01-01T04:30:00.00-05:00,
1500	   }

1502	4.2.2.  LocalTimeWindow

1504	   A LocalTimeWindow object describes a time range in local time.  The
1505	   reader of this object MUST interpret it as "the local time at the
1506	   location of execution".  For example, if the time window states 2AM
1507	   to 4AM local time then a dCDN that has presence in both London (UTC)
1508	   and New York (UTC-05:00) will execute the trigger at 2AM-4AM UTC in
1509	   London and at 2AM-4AM UTC-05:00 in New York.

1511	      Property: start

1513	         Description: The start time of the window.

1515	         Type: JSON string formatted as DateLocalTime as defined in
1516	         Section 4.2.3.

1518	         Mandatory: No, but at least one of "start" or "end" MUST be
1519	         present and non-empty.

1521	      Property: end

1523	         Description: The end time of the window.

1525	         Type: JSON string formatted as DateLocalTime as defined in
1526	         Section 4.2.3.

1528	         Mandatory: No, but at least one of "start" or "end" MUST be
1529	         present and non-empty.

1531	   Example JSON serialized LocalTimeWindow object that describes a local
1532	   time window from 02:30 01/01/2000 to 04:30 01/01/2000.

1534	   {
1535	     "start": 2000-01-01T02:30:00.00,
1536	     "end": 2000-01-01T04:30:00.00,
1537	   }

1539	4.2.3.  DateLocalTime

1541	   DateLocalTime is a timestamp that follows the date and local time
1542	   notation in Section 4.3.2 of [ISO8601] as a complete date and time
1543	   extended representation, where the time zone designator is omitted.
1544	   In addition, for simplicity and as exact accuracy is not an objective
1545	   in this case, this specification does not support the decimal
1546	   fractions of seconds, and does not take leap second into
1547	   consideration.

1549	   Type: JSON string using the format "date-local-time" as defined in
1550	   Section 4.2.3.1.

1552	4.2.3.1.  Date and Local Time Format

1554	   The Date and Local Time format is specified here using the syntax
1555	   description notation defined in [ABNF].

1557	   date-fullyear   = 4DIGIT
1558	   date-month      = 2DIGIT  ; 01-12
1559	   date-mday       = 2DIGIT  ; 01-28, 01-29, 01-30, 01-31 based on
1560	                             ; month/year
1561	   time-hour       = 2DIGIT  ; 00-23
1562	   time-minute     = 2DIGIT  ; 00-59
1563	   time-second     = 2DIGIT  ; 00-59 leap seconds are not supported

1565	   local-time      = time-hour ":" time-minute ":" time-second
1566	   full-date       = date-fullyear "-" date-month "-" date-mday
1567	   date-local-time = full-date "T" local-time

1569	   Example time representing 09:00AM on 01/01/2000 local time:

1571	   2000-01-01T09:00:00.00

1573	      NOTE: Per [ABNF] and [ISO8601], the "T" character in this syntax
1574	      may alternatively be lower case "t".  For simplicity, Applications
1575	      that generate the "date-local-time" format defined here, SHOULD
1576	      only use the upper case letter "T".

1578	4.2.3.2.  Restrictions

1580	   The grammar element date-mday represents the day number within the
1581	   current month.  The maximum value varies based on the month and year
1582	   as follows:

1584	   Month Number  Month/Year           Maximum value of date-mday
1585	   ------------  ----------           --------------------------
1586	   01            January              31
1587	   02            February, normal     28
1588	   02            February, leap year  29
1589	   03            March                31
1590	   04            April                30
1591	   05            May                  31
1592	   06            June                 30
1593	   07            July                 31
1594	   08            August               31
1595	   09            September            30
1596	   10            October              31
1597	   11            November             30
1598	   12            December             31

1600	   See Appendix C of [RFC3339] for a sample C code that determines if a
1601	   year is a leap year.

1603	   The grammar element time-second may have the values 0-59.  The value
1604	   of 60 that is used in [ISO8601] to represent a leap second MUST NOT
1605	   be used.

1607	   Although [ISO8601] permits the hour to be "24", this profile of
1608	   [ISO8601] only allows values between "00" and "23" for the hour in
1609	   order to reduce confusion.

1611	5.  Footprint and Capabilities

1613	   This section covers the FCI objects required for advertisement of the
1614	   extensions and properties introduced in this document.

1616	5.1.  CI/T Versions Capability Object

1618	   The CI/T versions capability object is used to indicate support for
1619	   one or more CI/T objects versions.  Note that the default version as
1620	   originally defined in [RFC8007] MUST be implicitly supported
1621	   regardless of the versions listed in this capability object.

1623	      Property: versions

1625	         Description: A list of version numbers.

1627	         Type: An array of JSON strings

1629	         Mandatory: No.  The default is version 1.  A missing or an
1630	         empty versions list means that only version 1 of the interface
1631	         and objects is supported.

1633	5.1.1.  CI/T Versions Capability Object Serialization

1635	   The following shows an example of a JSON serialized CI/T Versions
1636	   Capability object serialization for a dCDN that supports versions 2
1637	   and 2.1 of the CI/T interface.

1639	   {
1640	    "capabilities": [
1641	      {
1642	        "capability-type": "FCI.TriggerVersion",
1643	        "capability-value": {
1644	          "versions": [ "1", "2", "2.1" ]
1645	        },
1646	        "footprints": [
1647	          <Footprint objects>
1648	        ]
1649	      }
1650	    ]
1651	   }

1653	5.2.  CI/T Playlist Protocol Capability Object

1655	   The CI/T Playlist Protocol capability object is used to indicate
1656	   support for one or more MediaProtocol types listed in Section 6.3 by
1657	   the playlists property of the "trigger.v2" object.

1659	      Property: media-protocols

1661	         Description: A list of media protocols.

1663	         Type: A list of MediaProtocol (from the CDNI Triggers media
1664	         protocol types Section 6.3)

1666	         Mandatory: No.  The default, in case of a missing or an empty
1667	         list, is none supported.

1669	5.2.1.  CI/T Playlist Protocol Capability Object Serialization

1671	   The following shows an example of a JSON serialized CI/T Playlist
1672	   Protocol Capability object serialization for a dCDN that supports
1673	   "hls" and "dash".

1675	   {
1676	    "capabilities": [
1677	      {
1678	        "capability-type": "FCI.TriggerPlaylistProtocol",
1679	        "capability-value": {
1680	          "media-protocols": ["hls", "dash"]
1681	        },
1682	        "footprints": [
1683	          <Footprint objects>
1684	        ]
1685	      }
1686	    ]
1687	   }

1689	5.3.  CI/T Trigger Extension Capability Object

1691	   The CI/T Generic Extension capability object is used to indicate
1692	   support for one or more GenericExtensionObject types.

1694	      Property: trigger-extension

1696	         Description: A list of supported CDNI CI/T
1697	         GenericExtensionObject types.

1699	         Type: List of strings corresponding to entries from the "CDNI
1700	         Payload Types" registry [RFC7736] that are under the CIT
1701	         namespace, and that correspond to CDNI CI/T
1702	         GenericExtensionObject objects.

1704	         Mandatory: No.  The default, in case of a missing or an empty
1705	         list, MUST be interpreted as "no GenericExtensionObject types
1706	         are supported".  A non-empty list MUST be interpreted as
1707	         containing "the only GenericExtensionObject types that are
1708	         supported".

1710	5.3.1.  CI/T Trigger Extension Capability Object Serialization

1712	   The following shows an example of a JSON serialized CI/T Trigger
1713	   Extension Capability object serialization for a dCDN that supports
1714	   the "CIT.LocationPolicy" and the "CIT.TimePolicy" objects.

1716	   {
1717	    "capabilities": [
1718	      {
1719	        "capability-type": "FCI.TriggerGenericExtension",
1720	        "capability-value": {
1721	          "trigger-extension": ["CIT.LocationPolicy", "CIT.TimePolicy"]
1722	        },
1723	        "footprints": [
1724	          <Footprint objects>
1725	        ]
1726	      }
1727	    ]
1728	   }

1730	6.  IANA Considerations

1732	6.1.  CDNI Payload Types

1734	   This document requests the registration of the following CDNI Payload
1735	   Types under the IANA "CDNI Payload Types" registry defined in
1736	   [RFC7736]:

1738	              +-----------------------------+---------------+
1739	              | Payload Type                | Specification |
1740	              +-----------------------------+---------------+
1741	              | ci-trigger-command.v2       | RFCthis       |
1742	              | ci-trigger-status.v2        | RFCthis       |
1743	              | CIT.LocationPolicy          | RFCthis       |
1744	              | CIT.TimePolicy              | RFCthis       |
1745	              | FCI.TriggerVersion          | RFCthis       |
1746	              | FCI.TriggerPlaylistProtocol | RFCthis       |
1747	              | FCI.TriggerGenericExtension | RFCthis       |
1748	              +-----------------------------+---------------+

1750	   [RFC Editor: Please replace RFCthis with the published RFC number for
1751	   this document.]

1753	6.1.1.  CDNI ci-trigger-command.v2 Payload Type

1755	   Purpose: The purpose of this payload type is to distinguish version 2
1756	   of the CI/T command (and any associated capability advertisement)

1758	   Interface: CI/T

1760	   Encoding: see Section 3.1

1762	6.1.2.  CDNI ci-trigger-status.v2 Payload Type

1764	   Purpose: The purpose of this payload type is to distinguish version 2
1765	   of the CI/T status resource response (and any associated capability
1766	   advertisement)

1768	   Interface: CI/T

1770	   Encoding: see Section 3.1

1772	6.1.3.  CDNI CI/T LocationPolicy Trigger Extension Type

1774	   Purpose: The purpose of this Trigger Extension type is to distinguish
1775	   LocationPolicy CIT Trigger Extension objects.

1777	   Interface: CI/T

1779	   Encoding: see Section 4.1

1781	6.1.4.  CDNI CI/T TimePolicy Trigger Extension Type

1783	   Purpose: The purpose of this Trigger Extension type is to distinguish
1784	   TimePolicy CI/T Trigger Extension objects.

1786	   Interface: CI/T

1788	   Encoding: see Section 4.2

1790	6.1.5.  CDNI FCI CI/T Versions Payload Type

1792	   Purpose: The purpose of this payload type is to distinguish FCI
1793	   advertisement objects for CI/T Triggers Versions objects

1795	   Interface: FCI

1797	   Encoding: see Section 5.1.1

1799	6.1.6.  CDNI FCI CI/T Playlist Protocol Payload Type

1801	   Purpose: The purpose of this payload type is to distinguish FCI
1802	   advertisement objects for CI/T Playlist Protocol objects

1804	   Interface: FCI

1806	   Encoding: see Section 5.2.1

1808	6.1.7.  CDNI FCI CI/T Extension Objects Payload Type

1810	   Purpose: The purpose of this payload type is to distinguish FCI
1811	   advertisement objects for CI/T Extension objects

1813	   Interface: FCI

1815	   Encoding: see Section 5.3.1

1817	6.2.  CDNI CI/T Trigger Error Codes types

1819	   The IANA is requested to update the "CDNI CI/T Error Codes"
1820	   subregistry (defined in Section 7.3 of [RFC8007] and located at
1821	   <https://www.iana.org/assignments/cdni-parameters>) with the
1822	   following registration:

1824	   +------------+--------------------------------------+---------------+
1825	   | Error Code | Description                          | Specification |
1826	   +------------+--------------------------------------+---------------+
1827	   | eextension | The dCDN failed to parse a generic   | Section       |
1828	   |            | "mandatory-to-enforce" extension     | Section 3.3.7 |
1829	   |            | object, or does not support this     | of this       |
1830	   |            | extension.                           | document.     |
1831	   +------------+--------------------------------------+---------------+

1833	6.3.  CDNI Media protocol types

1835	   The IANA is requested to create a new "CDNI MediaProtocol Types"
1836	   subregistry in the "Content Delivery Networks Interconnection (CDNI)
1837	   Parameters" registry.  The "CDNI MediaProtocol Types" namespace
1838	   defines the valid MediaProtocol object values in
1839	   Section Section 3.3.4, used by the Playlist object.  Additions to the
1840	   MediaProtocol namespace conform to the "Specification Required"
1841	   policy as defined in Section 4.6 of [RFC8126], where the
1842	   specification defines the MediaProtocol Type and the protocol to
1843	   which it is associated.  The designated expert will verify that new
1844	   protocol definitions do not duplicate existing protocol definitions
1845	   and prevent gratuitous additions to the namespace.

1847	   The following table defines the initial MediaProtocol values
1848	   corresponding to the HLS, MSS, and DASH protocols:

1850	   +---------------+-------------------+---------------+---------------+
1851	   | MediaProtocol | Description       | Specification | Protocol      |
1852	   | Type          |                   |               | Specification |
1853	   +---------------+-------------------+---------------+---------------+
1854	   | hls           | HTTP Live         | RFCthis       | RFC 8216      |
1855	   |               | Streaming         |               | [RFC8216]     |
1856	   | mss           | Microsoft Smooth  | RFCthis       | MSS [MSS]     |
1857	   |               | Streaming         |               |               |
1858	   | dash          | Dynamic Adaptive  | RFCthis       | MPEG-DASH     |
1859	   |               | Streaming over    |               | [MPEG-DASH]   |
1860	   |               | HTTP (MPEG-DASH)  |               |               |
1861	   +---------------+-------------------+---------------+---------------+

1863	   [RFC Editor: Please replace RFCthis with the published RFC number for
1864	   this document.]

1866	7.  Security Considerations

1868	   All security considerations listed in Section 8 of [RFC8007] and
1869	   Section 7 of [RFC8008] apply to this document as well.

1871	   This document defines the capability to use regular expression within
1872	   the trigger specification for more granular content selection.  The
1873	   usage of regex introduced the risk of regex complexity attacks, a.k.a
1874	   ReDos attacks.  An attacker may be able to craft a regular expression
1875	   that can exhaust server resources and may take exponential time in
1876	   the worst case.  An implementation MUST protect itself at a minimum
1877	   by accepting triggers only from an authenticated party over a secured
1878	   connection.  An implementation SHOULD also protect itself by using
1879	   secure programing techniques and decline trigger commands that use
1880	   potentially risky regex, such techniques are readily available in
1881	   secure programming literature and are beyond the scope of this
1882	   document.

1884	8.  Acknowledgments

1886	   TBD

1888	9.  Contributors

1890	   The authors thank all members of the "Streaming Video Alliance" (SVA)
1891	   and specifically contributions by members of Open Caching Working
1892	   Group in support of this document.  The authors also thank Kevin Ma
1893	   for his guidance and careful and methodical reviews.

1895	10.  References

1897	10.1.  Normative References

1899	   [ABNF]     Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
1900	              Specifications: ABNF", STD 68, RFC 5234,
1901	              DOI 10.17487/RFC5234, January 2008,
1902	              <https://www.rfc-editor.org/info/rfc5234>.

1904	   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
1905	              Requirement Levels", BCP 14, RFC 2119,
1906	              DOI 10.17487/RFC2119, March 1997,
1907	              <https://www.rfc-editor.org/info/rfc2119>.

1909	   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
1910	              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
1911	              <https://www.rfc-editor.org/info/rfc3339>.

1913	   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
1914	              Resource Identifier (URI): Generic Syntax", STD 66,
1915	              RFC 3986, DOI 10.17487/RFC3986, January 2005,
1916	              <https://www.rfc-editor.org/info/rfc3986>.

1918	   [RFC6707]  Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
1919	              Distribution Network Interconnection (CDNI) Problem
1920	              Statement", RFC 6707, DOI 10.17487/RFC6707, September
1921	              2012, <https://www.rfc-editor.org/info/rfc6707>.

1923	   [RFC7736]  Ma, K., "Content Delivery Network Interconnection (CDNI)
1924	              Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
1925	              December 2015, <https://www.rfc-editor.org/info/rfc7736>.

1927	   [RFC8006]  Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
1928	              "Content Delivery Network Interconnection (CDNI)
1929	              Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
1930	              <https://www.rfc-editor.org/info/rfc8006>.

1932	   [RFC8007]  Murray, R. and B. Niven-Jenkins, "Content Delivery Network
1933	              Interconnection (CDNI) Control Interface / Triggers",
1934	              RFC 8007, DOI 10.17487/RFC8007, December 2016,
1935	              <https://www.rfc-editor.org/info/rfc8007>.

1937	   [RFC8008]  Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
1938	              R., and K. Ma, "Content Delivery Network Interconnection
1939	              (CDNI) Request Routing: Footprint and Capabilities
1940	              Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
1941	              <https://www.rfc-editor.org/info/rfc8008>.

1943	   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
1944	              Writing an IANA Considerations Section in RFCs", BCP 26,
1945	              RFC 8126, DOI 10.17487/RFC8126, June 2017,
1946	              <https://www.rfc-editor.org/info/rfc8126>.

1948	   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
1949	              Interchange Format", STD 90, RFC 8259,
1950	              DOI 10.17487/RFC8259, December 2017,
1951	              <https://www.rfc-editor.org/info/rfc8259>.

1953	10.2.  Informative References

1955	   [ISO8601]  ISO, "Data elements and interchange formats -- Information
1956	              interchange -- Representation of dates and times",
1957	              ISO 8601:2004, Edition 3, 12 2004,
1958	              <https://www.iso.org/standard/40874.html>.

1960	   [MPEG-DASH]
1961	              ISO, "Information technology -- Dynamic adaptive streaming
1962	              over HTTP (DASH) -- Part 1: Media presentation description
1963	              and segment format", ISO/IEC 23009-1:2014, Edition 2, 05
1964	              2014, <https://www.iso.org/standard/65274.html>.

1966	   [MSS]      Microsoft, "[MS-SSTR]: Smooth Streaming Protocol",
1967	              Protocol Revision 8.0, September 2017,
1968	              <https://msdn.microsoft.com/en-us/library/ff469518.aspx>.

1970	   [OC-CM]    Finkelman, O., Ed., Devabhaktuni, J., and M. Stock, "Open
1971	              Caching Content Management Operations Specification",
1972	              November 2017,
1973	              <https://www.streamingvideoalliance.org/document/open-
1974	              caching-content-management-operations-specification/>.

1976	   [OCWG]     Streaming Video Alliance, "Open Caching",
1977	              <https://www.streamingvideoalliance.org/technical-groups/
1978	              open-caching/>.

1980	   [PCRE841]  Hazel, P., "Perl Compatible Regular Expressions",
1981	              Version 8.41, July 2017, <http://www.pcre.org/>.

1983	   [RFC8216]  Pantos, R., Ed. and W. May, "HTTP Live Streaming",
1984	              RFC 8216, DOI 10.17487/RFC8216, August 2017,
1985	              <https://www.rfc-editor.org/info/rfc8216>.

1987	   [SVA]      "Streaming Video Alliance",
1988	              <https://www.streamingvideoalliance.org>.

1990	Authors' Addresses

1992	   Ori Finkelman
1993	   Qwilt
1994	   6, Ha'harash
1995	   Hod HaSharon  4524079
1996	   Israel

1998	   Email: ori.finkelman.ietf@gmail.com

2000	   Sanjay Mishra
2001	   Verizon
2002	   13100 Columbia Pike
2003	   Silver Spring, MD  20904
2004	   USA

2006	   Email: sanjay.mishra@verizon.com

2008	   Nir B. Sopher
2009	   Qwilt
2010	   6, Ha'harash
2011	   Hod HaSharon  4524079
2012	   Israel

2014	   Email: nir@apache.org