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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: October 2, 2019                                  March 31, 2019

8	               CDNI Control Triggers Interface Extensions
9	                 draft-ietf-cdni-triggers-extensions-02

11	Abstract

13	   This document updates RFC 8007 to include generic extensions and more
14	   granular content matching options, required by the Open Caching
15	   architecture.  The Open Caching working group of the Streaming Video
16	   Alliance is focused on the delegation of video delivery request from
17	   commercial CDNs to a caching layer at the ISP.  In that aspect, Open
18	   Caching is a specific use case of CDNI, where the commercial CDN is
19	   the upstream CDN (uCDN) and the ISP caching layer is the downstream
20	   CDN (dCDN).  The extensions specified in this document to the CDNI
21	   Control Interface / Triggers are derived from requirements of Open
22	   Caching but are 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 October 2, 2019.

47	Copyright Notice

49	   Copyright (c) 2019 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  . . . . . . . . . . . . . . .   4
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 . . . . . . . . . . . . . . . .   5
73	       2.1.5.  Error Handling  . . . . . . . . . . . . . . . . . . .   6
74	     2.2.  CDNI Footprint and Capabilities Interface Extensions  . .   6
75	   3.  CI/T Version 2  . . . . . . . . . . . . . . . . . . . . . . .   7
76	     3.1.  CI/T Objects V2 . . . . . . . . . . . . . . . . . . . . .   7
77	     3.2.  Error Handling V2 . . . . . . . . . . . . . . . . . . . .   9
78	     3.3.  Properties of CI/T Version 2 objects  . . . . . . . . . .  10
79	       3.3.1.  Trigger Specification Version 2 . . . . . . . . . . .  10
80	       3.3.2.  RegexMatch  . . . . . . . . . . . . . . . . . . . . .  11
81	       3.3.3.  Playlist  . . . . . . . . . . . . . . . . . . . . . .  13
82	       3.3.4.  MediaProtocol . . . . . . . . . . . . . . . . . . . .  13
83	       3.3.5.  CI/T Trigger Extensions . . . . . . . . . . . . . . .  14
84	         3.3.5.1.  Enforcement Options . . . . . . . . . . . . . . .  14
85	         3.3.5.2.  GenericExtensionObject  . . . . . . . . . . . . .  17
86	       3.3.6.  Error Description Version 2 . . . . . . . . . . . . .  19
87	       3.3.7.  Error codes . . . . . . . . . . . . . . . . . . . . .  21
88	     3.4.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  21
89	       3.4.1.  Invalidation with Regex . . . . . . . . . . . . . . .  21
90	       3.4.2.  Preposition with Playlists  . . . . . . . . . . . . .  23
91	       3.4.3.  Extensions with Error Propagation . . . . . . . . . .  24
92	   4.  Trigger Extension Objects . . . . . . . . . . . . . . . . . .  26
93	     4.1.  LocationPolicy extension  . . . . . . . . . . . . . . . .  26
94	     4.2.  TimePolicy Extension  . . . . . . . . . . . . . . . . . .  28
95	       4.2.1.  UTCWindow . . . . . . . . . . . . . . . . . . . . . .  30
96	       4.2.2.  LocalTimeWindow . . . . . . . . . . . . . . . . . . .  31
97	       4.2.3.  DateLocalTime . . . . . . . . . . . . . . . . . . . .  32
98	         4.2.3.1.  Date and Local Time Format  . . . . . . . . . . .  32
99	         4.2.3.2.  Restrictions  . . . . . . . . . . . . . . . . . .  32
100	   5.  Footprint and Capabilities  . . . . . . . . . . . . . . . . .  33
101	     5.1.  CI/T Versions Capability Object . . . . . . . . . . . . .  33
102	       5.1.1.  CI/T Versions Capability Object Serialization . . . .  34
103	     5.2.  CI/T Playlist Protocol Capability Object  . . . . . . . .  34
104	       5.2.1.  CI/T Playlist Protocol Capability Object
105	               Serialization . . . . . . . . . . . . . . . . . . . .  34
106	     5.3.  CI/T Trigger Extension Capability Object  . . . . . . . .  35
107	       5.3.1.  CI/T Trigger Extension Capability Object
108	               Serialization . . . . . . . . . . . . . . . . . . . .  35
109	   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  36
110	     6.1.  CDNI Payload Types  . . . . . . . . . . . . . . . . . . .  36
111	       6.1.1.  CDNI ci-trigger-command.v2 Payload Type . . . . . . .  36
112	       6.1.2.  CDNI ci-trigger-status.v2 Payload Type  . . . . . . .  37
113	       6.1.3.  CDNI CI/T LocationPolicy Trigger Extension Type . . .  37
114	       6.1.4.  CDNI CI/T TimePolicy Trigger Extension Type . . . . .  37
115	       6.1.5.  CDNI FCI CI/T Versions Payload Type . . . . . . . . .  37
116	       6.1.6.  CDNI FCI CI/T Playlist Protocol Payload Type  . . . .  37
117	       6.1.7.  CDNI FCI CI/T Extension Objects Payload Type  . . . .  38
118	     6.2.  CDNI CI/T Trigger Error Codes types . . . . . . . . . . .  38
119	     6.3.  CDNI Media protocol types . . . . . . . . . . . . . . . .  38
120	   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  39
121	   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  39
122	   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  39
123	   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  40
124	     10.1.  Normative References . . . . . . . . . . . . . . . . . .  40
125	     10.2.  Informative References . . . . . . . . . . . . . . . . .  41
126	   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  41

128	1.  Introduction

130	   This document defines the objects and extensions required for
131	   granular content management operations.  For that purpose it extends
132	   CDNI Control Interface / Triggers [RFC8007] by adding new content
133	   selection options to the trigger specification and specifying a
134	   generic extension mechanism that enables adding future functions for
135	   controlling the trigger execution.  This document also defines and
136	   initial set of extension objects.  This document gives examples for
137	   the extensions specified herein, for complete examples of the trigger
138	   interface usage see Section 6 of [RFC8007].

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

142	   The CDNI Footprint and Capability Interface is described in
143	   [RFC8008].

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

147	1.1.  Terminology

149	   This document reuses the terminology defined in [RFC6707], [RFC8006],
150	   [RFC8007], and [RFC8008].

152	   Additionally, the following terms are used throughout this document
153	   and are defined as follows:

155	   o  HLS - HTTP Live Streaming

157	   o  DASH - Dynamic Adaptive Streaming Over HTTP

159	   o  MSS - Microsoft Smooth Streaming

161	1.2.  Structure of this document

163	   The remainder of this document is organized as follows:

165	   o  Section 2 gives an overview of the extensions specified in this
166	      document.

168	   o  Section 3 specifies version 2 of the CDNI Control Interface /
169	      Triggers.

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

173	   o  Section 5 specifies Footprint and Capability objects for CI/T
174	      version and extensions.

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

178	   o  Section 7 describes the security considerations for the specified
179	      properties and extensions.

181	2.  Interfaces Extensions Overview

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

187	2.1.  CDNI Control Interface / Triggers Extensions

189	2.1.1.  CI/T Objects

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

195	2.1.2.  Trigger Specification

197	   This document specifies version 2 of the Trigger Specification which
198	   is an enhancement of the Trigger Specification that includes all
199	   properties as defined in Section 5.2.1 of [RFC8007] as well as the
200	   additional properties required by the use cases listed below in
201	   Section 2.1.3 and Section 2.1.4.

203	2.1.3.  Content Selection

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

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

215	   o  Content Playlist - Using video playlist files, a uCDN can trigger
216	      an operation that will be applied to a collection of distinct
217	      media files in a format that is natural for a streaming video
218	      content provider.  A playlist may have several formats,
219	      specifically HTTP Live Streaming (HLS) *.m3u8 manifest [RFC8216],
220	      Microsoft Smooth Streaming (MSS) *.ismc client manifest [MSS], and
221	      Dynamic Adaptive Streaming over HTTP (DASH) *.mpd file [ISO/IEC
222	      23009-1:2014] [MPEG-DASH].

224	2.1.4.  Trigger Extensibility

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

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

237	   o  CIT.LocationPolicy (for controlling the locations in which the
238	      trigger is executed)

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

243	   Example use cases

245	   o  Pre-position with cache location policy

247	   o  Purge content with cache location policy

249	   o  Pre-position at a specific time

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

254	2.1.5.  Error Handling

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

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

262	   o  Extension errors - report an error that happened due to an
263	      extension object.

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

268	2.2.  CDNI Footprint and Capabilities Interface Extensions

270	   Extending the trigger mechanism with optional properties requires the
271	   ability for the dCDN to advertise which optional properties it
272	   supports.

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

279	   Example use cases
280	   o  Trigger types: Advertise which trigger types are supported by the
281	      dCDN.  CDNI defines three trigger types (purge, invalidate, pre-
282	      position), but it does not necessarily mean that all dCDNs support
283	      all of them.  The uCDN may prefer to work only with dCDN that
284	      support what the uCDN needs.

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

293	   o  Trigger extensions: Advertise which trigger extensions object
294	      types are supported by the dCDN.

296	3.  CI/T Version 2

298	   [RFC8007] does not define a version number and versioning scheme.
299	   We, therefore, designate the interface and objects as defined in
300	   Section 5 of [RFC8007] as version 1.  The following sections define
301	   version 2 of the CI/T objects and their properties as extensions of
302	   version 1.

304	3.1.  CI/T Objects V2

306	   Version 2 of the CI/T interface requires the support of the following
307	   objects:

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

315	   o  Trigger Status Resource v2: A trigger status resource response
316	      using the payload type ci-trigger-status.v2.  Version 2 MUST only
317	      use "trigger.v2" objects as defined in Section 3.3.1, instead of a
318	      "trigger" object, as well as "errors.v2" array as defined in
319	      Section 3.3.6, instead of a "errors" array.  All other properties
320	      of the trigger status v2 are as defined in Section 5.1.2 of
321	      [RFC8007].  The errors array "errors.v2" is a list of all errors
322	      that occurred in any of the downstream CDNs along the execution
323	      path.  When a downstream CDN, dCDN-A, propagates a trigger to
324	      another downstream CDN, dCDN-B, it MUST also propagated back all
325	      errors reported by dCDN-B in the trigger status resource and add
326	      them to its own trigger status resource.

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

331	   Usage example of version 2 of trigger command

333	   REQUEST:

335	       POST /triggers HTTP/1.1
336	       User-Agent: example-user-agent/0.1
337	       Host: triggers.dcdn.example.com
338	       Accept: */*
339	       Content-Type: application/cdni; ptype=ci-trigger-command.v2
340	       {
341	         "trigger.v2": { <properties of a trigger.v2 object> },
342	         "cdn-path": [ "AS64496:0" ]
343	       }

345	   RESPONSE:

347	       HTTP/1.1 201 Created
348	       Date: Wed, 04 May 2016 08:48:10 GMT
349	       Content-Length: 467
350	       Content-Type: application/cdni; ptype=ci-trigger-status.v2
351	       Location: https://triggers.dcdn.example.com/triggers/0
352	       Server: example-server/0.1

354	       {
355	          "errors.v2": [ { <properties of 1st error.v2 object> },
356	                           ...,
357	                         { <properties of Nth error.v2 object> }
358	          ],
359	          "ctime": 1462351690,
360	          "etime": 1462351698,
361	          "mtime": 1462351690,
362	          "status": "pending",
363	          "trigger.v2": { <properties of a trigger.v2 object> }
364	       }

366	   Usage example of version 2 of trigger status for the trigger created
367	   in the above trigger command example:

369	   REQUEST:

371	       GET /triggers/0 HTTP/1.1
372	       User-Agent: example-user-agent/0.1
373	       Host: triggers.dcdn.example.com
374	       Accept: */*

376	   RESPONSE:

378	       HTTP/1.1 200 OK
379	       Content-Length: 467
380	       Expires: Wed, 04 May 2016 08:49:10 GMT
381	       Server: example-server/0.1
382	       ETag: "6990548174277557683"
383	       Cache-Control: max-age=60
384	       Date: Wed, 04 May 2016 08:48:10 GMT
385	       Content-Type: application/cdni; ptype=ci-trigger-status.v2

387	       {
388	          "errors.v2": [ { <properties of 1st error.v2 object> },
389	                           ...,
390	                         { <properties of Nth error.v2 object> }
391	          ],
392	          "ctime": 1462351690,
393	          "etime": 1462351698,
394	          "mtime": 1462351690,
395	          "status": "pending",
396	          "trigger.v2": { <properties of a trigger.v2 object> }
397	       }

399	3.2.  Error Handling V2

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

407	   o  Extension errors - report an error that happened due to an
408	      extension object.  As extension objects are expected to be added
409	      to the interface as new requirements comes along, it is expected
410	      that in some cases a dCDN may receive a trigger that it cannot
411	      process or does not understand.  It is essential for the trigger
412	      caller to be able to understand when such errors occur so they can
413	      take actions to fix them.  This document adds a mechanism to
414	      report extension errors.

416	   o  Error propagation - enable the uCDN to traceback an error to the
417	      dCDN in which it occurred.  CDNI triggers may be propagated over a
418	      chain of downstream CDNs.  Let us take for example an upstream
419	      (uCDN-A) CDN A that is delegating to a downstream CDN B (dCDN-B)
420	      and dCDN-B is delegating to a downstream CDN C (dCDN-C).  Triggers
421	      sent from uCDN-A to dCDN-B may be redistributed from dCDN-B to
422	      dCDN-C and errors can happen anywhere along the path.  Therefore,
423	      it is essential for uCDN-A that sets the trigger, to be able to
424	      trace back an error to the downstream CDN where it occurred.  This
425	      document adds a mechanism to propagate the ID of the faulty dCDN
426	      back to the uCDN by adding the CDN ID to the error description.
427	      When a downstream dCDN-B propagates a trigger to another
428	      downstream dCDN-C, it MUST also propagate back the errors received
429	      in the trigger status resource from dCDN-C by adding them to the
430	      errors array in its own status resource to be sent back to the
431	      originating uCDN-A.  This makes sure that the trigger originating
432	      upstream CDN will receive an array of errors that occurred in all
433	      the CDNs along the execution path, each error carrying its own CDN
434	      identifier.

436	3.3.  Properties of CI/T Version 2 objects

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

441	3.3.1.  Trigger Specification Version 2

443	   Version 2 of the Trigger Specification adds the following properties
444	   on top of the existing properties of the trigger specification
445	   defined in Section 5.2.1 of [RFC8007].

447	      Property: content.regexs

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

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

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

457	      Property: content.playlists

459	         Description: Playlists of content the CI/T trigger command
460	         applies to.

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

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

467	      Property: extensions

469	         Description: Array of trigger extension data.

471	         Type: Array of GenericTriggerExtension objects (see
472	         Section 3.3.5.2).

474	         Mandatory-to-Specify: No.  The default is no extensions.

476	   Example of an invalidation trigger.v2 with a list of regex objects, a
477	   list of playlist objects, and extensions:

479	   {
480	     "trigger.v2": {
481	       "type": "invalidate",
482	       "content.regexs": [ <list of RegexMatch objects> ],
483	       "content.playlists": [ <list of Playlist objects> ],
484	       "extensions": [ <list of GenericTriggerExtension objects ]
485	     },
486	     "cdn-path": [ "AS64496:0" ]
487	   }

489	3.3.2.  RegexMatch

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

495	      Property: regex

497	         Description: A regular expression for URI matching.

499	         Type: A regular expression to match against the URI, i.e
500	         against the path-absolute and the query string parameters
501	         [RFC3986].  The regular expression string MUST be compatible
502	         with PCRE [PCRE841].

504	         Note: Because '\' has special meaning in JSON [RFC8259] as the
505	         escape character within JSON strings, the regular expression
506	         character '\' MUST be escaped as '\\'.

508	         Mandatory: Yes.

510	      Property: case-sensitive
511	         Description: Flag indicating whether or not case-sensitive
512	         matching should be used.

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

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

520	      Property: match-query-string

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

525	         Type: JSON boolean.  Either "true" (the full URI, including the
526	         query part, should be compared against the regex) or "false"
527	         (the query part of the URI should be dropped before comparison
528	         with the given regex).

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

535	   Example of a case sensitive, no query parameters, regex match
536	   against:

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

541	   {
542	     "regex": "^(https:\\/\\/video\\.example\\.com)\\/([a-z])\\/movie1\
543	              \/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
544	     "case-sensitive": true,
545	     "match-query-string": false
546	   }

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

553	   https://video.example.com/d/movie1/5/index.m3u8
554	   or
555	   https://video.example.com/k/movie1/4/013.ts

557	3.3.3.  Playlist

559	   A Playlist consists of a full URL and a media protocol identifier.
560	   An implementation that supports a specific playlist media protocol
561	   MUST be able to parse playlist files of that protocol type and
562	   extract, possibly recursively, the URLs to all media objects and/or
563	   sub playlist files, and apply the trigger to each one of them
564	   separately.

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

568	      Property: playlist

570	         Description: A URL to the playlist file.

572	         Type: A URL represented as a JSON string.

574	         Mandatory: Yes.

576	      Property: media-protocol

578	         Description: Media protocol to be when parsing and interpreting
579	         this playlist.

581	         Type: MediaProtocol (see Section 3.3.4).

583	         Mandatory: Yes.

585	   Example of a HLS playlist:

587	   {
588	     "playlist": "https://www.example.com/hls/title/index.m3u8",
589	     "media-protocol": "hls"
590	   }

592	3.3.4.  MediaProtocol

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

598	   Type: JSON string

600	   Example:

602	   "dash"

604	3.3.5.  CI/T Trigger Extensions

606	   A "trigger.v2" object, as defined in Section 3.3.1 includes an
607	   optional array of trigger extension objects.  A trigger extension
608	   contain properties that are used as directives for dCDN when
609	   executing the trigger command -- for example, location policies, time
610	   policies and so on.  Each such CDNI Trigger extension is a
611	   specialization of a CDNI GenericTriggerExtension object.  The
612	   GenericTriggerExtension object abstracts the basic information
613	   required for trigger distribution from the specifics of any given
614	   property (i.e., property semantics, enforcement options, etc.).  All
615	   trigger extensions are optional, and it is thus the responsibility of
616	   the extension specification to define a consistent default behavior
617	   for the case the extension is not present.

619	3.3.5.1.  Enforcement Options

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

624	   The GenericTriggerExtension object defines the properties contained
625	   within it as well as whether or not the properties are "mandatory-to-
626	   enforce".  If the dCDN does not understand or support a mandatory-to-
627	   enforce property, the dCDN MUST NOT execute the trigger command.  If
628	   the extension is not mandatory-to-enforce, then that
629	   GenericTriggerExtension object can be safely ignored and the trigger
630	   command can be processed in accordance with the rest of the CDNI
631	   Trigger spec.

633	   Although a CDN MUST NOT execute a trigger command if a mandatory-to-
634	   enforce extension cannot be enforced, it could still be safe to
635	   redistribute that trigger (the "safe-to-redistribute" property) to
636	   another CDN without modification.  For example, in the cascaded CDN
637	   case, a transit CDN (tCDN) could convey mandatory-to-enforce trigger
638	   extension to a dCDN.  For a trigger extension that does not require
639	   customization or translation (i.e., trigger extension that is safe-
640	   to-redistribute), the data representation received off the wire MAY
641	   be stored and redistributed without being understood or supported by
642	   the tCDN.  However, for trigger extension that requires translation,
643	   transparent redistribution of the uCDN trigger values might not be
644	   appropriate.  Certain triggers extensions can be safely, though
645	   perhaps not optimally, redistributed unmodified.  For example, pre-
646	   position command might be executed in suboptimal times for some
647	   geographies if transparently redistributed, but it might still work.

649	   Redistribution safety MUST be specified for each
650	   GenericTriggerExtension property.  If a CDN does not understand or
651	   support a given GenericTriggerExtension property that is not safe-to-
652	   redistribute, the CDN MUST set the "incomprehensible" flag to true
653	   for that GenericTriggerExtension object before redistributing it.
654	   The "incomprehensible" flag signals to a dCDN that trigger metadata
655	   was not properly transformed by the tCDN.  A CDN MUST NOT attempt to
656	   execute a trigger that has been marked as "incomprehensible" by a
657	   uCDN.

659	   tCDNs MUST NOT change the value of mandatory-to-enforce or safe-to-
660	   redistribute when propagating a trigger to a dCDN.  Although a tCDN
661	   can set the value of "incomprehensible" to true, a tCDN MUST NOT
662	   change the value of "incomprehensible" from true to false.

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

669	   +-------+-------+------------+--------------------------------------+
670	   | MtE   | StR   | Extension  | Trigger action                       |
671	   |       |       | object     |                                      |
672	   |       |       | understood |                                      |
673	   |       |       | by tCDN    |                                      |
674	   +-------+-------+------------+--------------------------------------+
675	   | False | True  | True       | Can execute and redistribute.        |
676	   | False | True  | False      | Can execute and redistribute.        |
677	   | False | False | False      | Can execute. MUST set                |
678	   |       |       |            | "incomprehensible" to true when      |
679	   |       |       |            | redistributing.                      |
680	   | False | False | True       | Can execute. Can redistribute after  |
681	   |       |       |            | transforming the trigger extension   |
682	   |       |       |            | (if the CDN knows how to do so       |
683	   |       |       |            | safely); otherwise, MUST set         |
684	   |       |       |            | "incomprehensible" to true when      |
685	   |       |       |            | redistributing.                      |
686	   | True  | True  | True       | Can execute and redistribute.        |
687	   | True  | True  | False      | MUST NOT execute but can             |
688	   |       |       |            | redistribute..                       |
689	   | True  | False | True       | Can execute. Can redistribute after  |
690	   |       |       |            | transforming the trigger extension   |
691	   |       |       |            | (if the CDN knows how to do so       |
692	   |       |       |            | safely); otherwise, MUST set         |
693	   |       |       |            | "incomprehensible" to true when      |
694	   |       |       |            | redistributing.                      |
695	   | True  | False | False      | MUST NOT serve.  MUST set            |
696	   |       |       |            | "incomprehensible" to true when      |
697	   |       |       |            | redistributing.                      |
698	   +-------+-------+------------+--------------------------------------+

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

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

708	   +-------+--------+---------------+----------------------------------+
709	   | MtE   | Incomp | Extension     | Trigger action                   |
710	   |       |        | object        |                                  |
711	   |       |        | understood by |                                  |
712	   |       |        | dCDN          |                                  |
713	   +-------+--------+---------------+----------------------------------+
714	   | False | False  | True          | Can execute.                     |
715	   | False | True   | True          | Can execute but MUST NOT         |
716	   |       |        |               | interpret/apply any trigger      |
717	   |       |        |               | extension marked as              |
718	   |       |        |               | "incomprehensible".              |
719	   | False | False  | False         | Can execute.                     |
720	   | False | True   | False         | Can execute but MUST NOT         |
721	   |       |        |               | interpret/apply any trigger      |
722	   |       |        |               | extension marked as              |
723	   |       |        |               | "incomprehensible".              |
724	   | True  | False  | True          | Can execute.                     |
725	   | True  | True   | True          | MUST NOT execute.                |
726	   | True  | False  | False         | MUST NOT execute.                |
727	   | True  | True   | False         | MUST NOT execute.                |
728	   +-------+--------+---------------+----------------------------------+

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

733	3.3.5.2.  GenericExtensionObject

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

738	      Property: generic-trigger-extension-type

740	         Description: Case-insensitive CDNI Trigger extension object
741	         type.

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

747	         Mandatory-to-Specify: Yes.

749	      Property: generic-trigger-extension-value

751	         Description: CDNI Trigger extension object.

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

756	         Mandatory-to-Specify: Yes.

758	      Property: mandatory-to-enforce

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

763	         Type: Boolean

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

768	      Property: safe-to-redistribute

770	         Description: Flag identifying whether or not this trigger
771	         extension can be safely redistributed without modification.

773	         Type: Boolean

775	         Mandatory-to-Specify: No.  Default is to allow transparent
776	         redistribution (i.e., a value of True).

778	      Property: incomprehensible

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

786	         Type: Boolean

788	         Mandatory-to-Specify: No.  Default is comprehensible (i.e., a
789	         value of False).

791	   Example of a GenericTriggerExtension containing a specific trigger
792	   extension object:

794	   {
795	     "generic-trigger-extension-type":
796	        <Type of this trigger extension object>,
797	     "generic-trigger-extension-value":
798	         {
799	           <properties of this trigger extension object>
800	         },
801	     "mandatory-to-enforce": true,
802	     "safe-to-redistribute": true,
803	     "incomprehensible": false
804	   }

806	3.3.6.  Error Description Version 2

808	   Version 2 of the Error Description adds the "content.playlists",
809	   "content.regexs", "extensions" and "cdn" properties on top of the
810	   existing properties of version 1 of the trigger Error Description as
811	   defined in Section 5.2.6 of [RFC8007].

813	      Properties: content.regexs, content.playlists

815	         Description: Content Regex and Playlist references copied from
816	         the Trigger Specification.  Only those regexs and playlists to
817	         which the error applies are included in each property, but
818	         those references MUST be exactly as they appear in the request;
819	         the dCDN MUST NOT change or generalize the URLs or Regexs.
820	         Note that these properties are added on top of the already
821	         existing properties: "metadata.urls", "content.urls",
822	         "metadata.patterns" and "content.patterns".

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

828	         Mandatory: At least one of "content.regexs",
829	         "content.playlists", "metadata.urls", "content.urls",
830	         "metadata.patterns" or "content.patterns" is mandatory in each
831	         Error Description object.

833	      Property: extensions

835	         Description: Array of trigger extension objects copied from the
836	         corresponding "extensions" array from the Trigger
837	         Specification.  Only those extensions to which the error
838	         applies are included, but those extensions MUST be exactly as
839	         they appear in the request.  where each object is copied from
840	         data copied from the
841	         Type: Array of GenericTriggerExtension objects, where each
842	         extension object is copied from the "extensions" array values
843	         in the Trigger Specification.

845	         Mandatory: No.  The "extensions" array SHOULD be used only if
846	         there were errors related to extension objects.

848	      Property: cdn

850	         Description: The CDN PID of the CDN where the error occurred.
851	         The "cdn" property is used by the originating uCDN or by
852	         propagating dCDN in order to distinguish in which CDN the error
853	         occured.

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

858	         Mandatory: Yes.

860	   Example of an Error Description object reporting a malformed
861	   Playlist:

863	   {
864	      "content.playlists": [
865	         {
866	           "playlist": "https://www.example.com/hls/title/index.m3u8",
867	           "media-protocol": "hls"
868	         }
869	       ],
870	      "description": "Failed to parse HLS playlist",
871	      "error": "econtent",
872	      "cdn": "AS64500:0"
873	   },

875	   Example of an Error Description object reporting an unsupported
876	   extension object:

878	 {
879	   "errors.v2": [
880	    {
881	      "extensions": [
882	         {
883	           "generic-trigger-extension-type":
884	              <Type of this erroneous trigger extension object>,
885	           "generic-trigger-extension-value":
886	               {
887	                 <properties of this erroneous trigger extension object>
888	               },
889	         }
890	       ],
891	      "description": "unrecognized extension <type>",
892	      "error": "eextension",
893	      "cdn": "AS64500:0"
894	    },
895	   ]
896	 }

898	3.3.7.  Error codes

900	   This document adds the error code "eextension" to the error codes
901	   table defined in Section 5.2.6 of [RFC8007].  This error code
902	   designates that an error occurred while parsing a generic trigger
903	   extension, or that the specific extension is not supported by the
904	   CDN.  A CDN that fails to parse or execute a generic extension object
905	   MUST report it using the "errors.v2" array within the trigger status
906	   resource, while setting the error code to "eextension" and providing
907	   an appropriate description.  The "eextension" error code is a
908	   registered type of "CDNI CI/T Trigger Error Codes" (see Section 6.2).

910	3.4.  Examples

912	   The following subsections provides usage examples of the specified
913	   interface extensions being used by the trigger command and status
914	   resource.

916	3.4.1.  Invalidation with Regex

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

923	REQUEST:

925	    POST /triggers HTTP/1.1
926	    User-Agent: example-user-agent/0.1
927	    Host: triggers.dcdn.example.com
928	    Accept: */*
929	    Content-Type: application/cdni; ptype=ci-trigger-command.v2
930	    {
931	      "trigger.v2": {
932	        "type": "invalidate",
933	        "content.regexs": [
934	          {
935	            "regex": "^(https:\\/\\/video\\.example\\.com)\\/
936	            ([a-z])\\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
937	            "case-sensitive": true,
938	            "match-query-string": false
939	          },
940	          { <RegexMatch #2> },
941	          ...
942	          { <RegexMatch #N> },
943	        ],
944	      },
945	      "cdn-path": [ "AS64496:0" ]
946	    }

948	RESPONSE:

950	    HTTP/1.1 201 Created
951	    Date: Wed, 04 May 2016 08:48:10 GMT
952	    Content-Length: 467
953	    Content-Type: application/cdni; ptype=ci-trigger-status.v2
954	    Location: https://triggers.dcdn.example.com/triggers/0
955	    Server: example-server/0.1

957	    {
958	       "errors.v2": [
959	         {
960	           "content.regexs": [
961	              {
962	                "regex": "^(https:\\/\\/video\\.example\\.com)\\/
963	                ([a-z])\\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
964	                "case-sensitive": true,
965	                "match-query-string": false
966	              },
967	            ],
968	           "description": "The dCDN rejected a regex due to complexity",
969	           "error": "ereject",
970	           "cdn": "AS64500:0"
971	         },
972	       ],
973	       "ctime": 1462351690,
974	       "etime": 1462351698,
975	       "mtime": 1462351690,
976	       "status": "failed",
977	       "trigger.v2": { <content of trigger object from the command> }
978	    }

980	3.4.2.  Preposition with Playlists

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

987	 REQUEST:

989	     POST /triggers HTTP/1.1
990	     User-Agent: example-user-agent/0.1
991	     Host: triggers.dcdn.example.com
992	     Accept: */*
993	     Content-Type: application/cdni; ptype=ci-trigger-command.v2
994	     {
995	       "trigger.v2": {
996	         "type": "preposition",
997	         "content.playlists": [
998	          {
999	           "playlist": "https://www.example.com/hls/title/index.m3u8",
1000	           "media-protocol": "hls"
1001	          },
1002	          { <Playlist #2> },
1003	          ...
1004	          { <Playlist #N> },
1005	         ],
1006	       },
1007	       "cdn-path": [ "AS64496:0" ]
1008	     }

1010	 RESPONSE:

1012	     HTTP/1.1 201 Created
1013	     Date: Wed, 04 May 2016 08:48:10 GMT
1014	     Content-Length: 467
1015	     Content-Type: application/cdni; ptype=ci-trigger-status.v2
1016	     Location: https://triggers.dcdn.example.com/triggers/0
1017	     Server: example-server/0.1

1019	     {
1020	       "errors.v2": [
1021	        {
1022	          "content.playlists": [
1023	           {
1024	             "playlist": "https://www.example.com/hls/title/index.m3u8",
1025	             "media-protocol": "hls"
1026	           },
1027	          ],
1028	          "description": "The dCDN was not able to parse the playlist",
1029	          "error": "econtent",
1030	          "cdn": "AS64500:0"
1031	        },
1032	       ],
1033	       "ctime": 1462351690,
1034	       "etime": 1462351698,
1035	       "mtime": 1462351690,
1036	       "status": "failed",
1037	       "trigger.v2": { <content of trigger object from the command> }
1038	     }

1040	3.4.3.  Extensions with Error Propagation

1042	   In the following example a CI/T "preposition" command is using two
1043	   extensions to control the way the trigger is executed.  In this
1044	   example the receiving dCDN identified as "AS64500:0" does not support
1045	   the first extension in the extensions array. dCDN "AS64500:0" further
1046	   distributes this trigger to another downstream CDN that is identified
1047	   as "AS64501:0", which does not support the second extension in the
1048	   extensions array.  The error is propagate from "AS64501:0" to
1049	   "AS64500:0" and the errors.v2 array reflects both errors.

1051	  REQUEST:

1053	      POST /triggers HTTP/1.1
1054	      User-Agent: example-user-agent/0.1
1055	      Host: triggers.dcdn.example.com
1056	      Accept: */*
1057	      Content-Type: application/cdni; ptype=ci-trigger-command.v2
1058	      {
1059	        "trigger.v2": {
1060	          "type": "preposition",
1061	          "content.playlists": [
1062	           {
1063	             "playlist": "https://www.example.com/hls/title/index.m3u8",
1064	             "media-protocol": "hls"
1065	           },
1066	          ],
1067	          "extensions": [
1068	              {
1069	                "generic-trigger-extension-type":

1071	                   <Type of trigger extension object #1>,
1072	                "generic-trigger-extension-value":
1073	                    {
1074	                      <properties of trigger extension object #1>
1075	                    },
1076	                "mandatory-to-enforce": false,
1077	                "safe-to-redistribute": true,
1078	              },
1079	              {
1080	                "generic-trigger-extension-type":
1081	                   <Type of trigger extension object #2>,
1082	                "generic-trigger-extension-value":
1083	                    {
1084	                      <properties of trigger extension object #2>
1085	                    },
1086	                "mandatory-to-enforce": false,
1087	                "safe-to-redistribute": true,
1088	              },
1089	          ],
1090	        },
1091	        "cdn-path": [ "AS64496:0" ]
1092	      }

1094	  RESPONSE:

1096	      HTTP/1.1 201 Created
1097	      Date: Wed, 04 May 2016 08:48:10 GMT
1098	      Content-Length: 467
1099	      Content-Type: application/cdni; ptype=ci-trigger-status.v2
1100	      Location: https://triggers.dcdn.example.com/triggers/0
1101	      Server: example-server/0.1

1103	      {
1104	         "errors.v2": [
1105	           {
1106	             "extensions": [
1107	                {
1108	                  "generic-trigger-extension-type":
1109	                     <Type of trigger extension object #1>,
1110	                  "generic-trigger-extension-value":
1111	                      {
1112	                        <properties of trigger extension object #1>
1113	                      },
1114	                  "mandatory-to-enforce": false,
1115	                  "safe-to-redistribute": true,
1116	                },
1117	              ],
1118	             "description": "unrecognized extension <type>",
1119	             "error": "eextension",
1120	             "cdn": "AS64500:0"
1121	           },
1122	           {
1123	             "extensions": [
1124	                {
1125	                  "generic-trigger-extension-type":
1126	                     <Type of trigger extension object #2>,
1127	                  "generic-trigger-extension-value":
1128	                      {
1129	                        <properties of trigger extension object #2>
1130	                      },
1131	                  "mandatory-to-enforce": false,
1132	                  "safe-to-redistribute": true,
1133	                },
1134	              ],
1135	             "description": "unrecognized extension <type>",
1136	             "error": "eextension",
1137	             "cdn": "AS64501:0"
1138	           },
1139	         ],
1140	         "ctime": 1462351690,
1141	         "etime": 1462351698,
1142	         "mtime": 1462351690,
1143	         "status": "failed",
1144	         "trigger.v2": { <content of trigger object from the command> }
1145	      }

1147	4.  Trigger Extension Objects

1149	   The objects defined below are intended to be used in the
1150	   GenericTriggerExtension object's generic-trigger-extension-value
1151	   field as defined in Section Section 3.3.5.2, and their generic-
1152	   trigger-extension-type property MUST be set to the appropriate CDNI
1153	   Payload Type as defined in Section 6.1 .

1155	4.1.  LocationPolicy extension

1157	   A content operation may be relevant for a specific geographical
1158	   region, or need to be excluded from a specific region.  In this case,
1159	   the trigger should be applied only to parts of the network that are
1160	   either "included" or "not excluded" by the location policy.  Note
1161	   that the restrictions here are on the cache location rather than the
1162	   client location.

1164	   The LocationPolicy object defines which CDN or cache locations for
1165	   which the trigger command is relevant.

1167	   Example use cases:

1169	   o  Pre-position: Certain contracts allow for pre-positioning or
1170	      availability of contract in all regions except for certain
1171	      excluded regions in the world, including caches.  For example,
1172	      some content cannot ever knowingly touch servers in a specific
1173	      country, including cached content.  Therefore, these regions MUST
1174	      be excluded from a pre-positioning operation.

1176	   o  Purge: In certain cases, content may have been located on servers
1177	      in regions where the content must not reside.  In such cases a
1178	      purge operation to remove content specifically from that region,
1179	      is required.

1181	   Object specification

1183	      Property: locations

1185	         Description: An Access List that allows or denies (blocks) the
1186	         trigger execution per cache location.

1188	         Type: Array of LocationRule objects (see Section 4.2.2.1 of
1189	         [RFC8006])

1191	         Mandatory-to-Specify: Yes.

1193	   If a location policy object is not listed within the trigger command,
1194	   the default behavior is to execute the trigger in all available
1195	   caches and locations of the dCDN.

1197	   The trigger command is allowed, or denied, for a specific cache
1198	   location according to the action of the first location whose
1199	   footprint matches against that cache's location.  If two or more
1200	   footprints overlap, the first footprint that matches against the
1201	   cache's location determines the action a CDN MUST take.  If the
1202	   "locations" property is an empty list or if none of the listed
1203	   footprints match the location of a specific cache location, then the
1204	   result is equivalent to a "deny" action.

1206	   The following is an example of generic trigger extension object
1207	   containing a location policy object that allows the trigger execution
1208	   in the US but blocks its execution in Canada:

1210	   {
1211	      "generic-trigger-extension-type": "CIT.LocationPolicy",
1212	      "generic-trigger-extension-value":
1213	       {
1214	          "locations": [
1215	            {
1216	              "action": "allow",
1217	              "footprints": [
1218	                {
1219	                  "footprint-type": "countrycode",
1220	                  "footprint-value": ["us"]
1221	                }
1222	              ]
1223	            },
1224	            {
1225	              "action": "deny",
1226	              "footprints": [
1227	                {
1228	                  "footprint-type": "countrycode",
1229	                  "footprint-value": ["ca"]
1230	                }
1231	              ]
1232	            }
1233	          ]
1234	       },
1235	      "mandatory-to-enforce": true,
1236	      "safe-to-redistribute": true,
1237	      "incomprehensible": false
1238	   }

1240	4.2.  TimePolicy Extension

1242	   A uCDN may wish to perform content management operations on the dCDN
1243	   in a specific schedule.  The TimePolicy extensions allows the uCDN to
1244	   instruct the dCDN to execute the trigger command in a desired time
1245	   window.  For example, a content provider that wishes to pre-populate
1246	   a new episode at off-peak time so that it would be ready on caches at
1247	   prime time when the episode is released for viewing.  A scheduled
1248	   operation enables the uCDN to direct the dCDN in what time frame to
1249	   execute the trigger.

1251	   A uCDN may wish to to schedule a trigger such that the dCDN will
1252	   execute it in local time, as it is measured in each region.  For
1253	   example, a uCDN may wish the dCDN to pull the content at off-peak
1254	   hours, between 2AM-4AM, however, as a CDN is distributed across
1255	   multiple time zones, the UTC definition of 2AM depends on the actual
1256	   location.

1258	   We define two alternatives for localized scheduling:

1260	   o  Regional schedule: When used in conjunction with the Location
1261	      Policy defined in Section 4.1, the uCDN can trigger separate
1262	      commands for different geographical regions, for each region using
1263	      a different schedule.  This allows the uCDN to control the
1264	      execution time per region.

1266	   o  Local Time schedule: We introduce a "local time" version for
1267	      Internet timestamps that follows the notation for local time as
1268	      defined in Section 4.2.2 of [ISO8601].  When local time is used,
1269	      that dCDN SHOULD execute the triggers at different absolute times,
1270	      according the local time of each execution location.

1272	   Object specification

1274	      Property: unix-time-window

1276	         Description: A UNIX epoch time window in which the trigger
1277	         SHOULD be executed.

1279	         Type: TimeWindow object using UNIX epoch timestamps (see
1280	         Section 4.2.3.2 of [RFC8006])

1282	         Mandatory-to-Specify: No, but exactly one of "unix-time-
1283	         window", "utc-window" or "local-time-window" MUST be present.

1285	      Property: utc-window

1287	         Description: A UTC time window in which the trigger SHOULD be
1288	         executed.

1290	         Type: UTCWindow object as defined in Section 4.2.1.

1292	         Mandatory-to-Specify: No, but exactly one of "unix-time-
1293	         window", "utc-window" or "local-time-window" MUST be present.

1295	      Property: local-time-window

1297	         Description: A local time window.  The dCDN SHOULD execute the
1298	         trigger at the defined time frame, interpreted as the the local
1299	         time per location.

1301	         Type: LocalTimeWindow object as defined in Section 4.2.2.

1303	         Mandatory-to-Specify: No, but exactly one of "unix-time-
1304	         window", "utc-window" or "local-time-window" MUST be present.

1306	   If a time policy object is not listed within the trigger command, the
1307	   default behavior is to execute the trigger in a time frame most
1308	   suitable to the dCDN taking under consideration other constrains and
1309	   / or obligations.

1311	   Example of a generic trigger extension object containing a time
1312	   policy object that schedules the trigger execution to a window
1313	   between 09:00 01/01/2000 UTC and 17:00 01/01/2000 UTC, using the
1314	   "unix-time-window" property:

1316	   {
1317	      "generic-trigger-extension-type": "CIT.TimePolicy",
1318	      "generic-trigger-extension-value":
1319	       {
1320	         "unix-time-window": {
1321	            "start": 946717200,
1322	            "end": 946746000
1323	         }
1324	       }
1325	      "mandatory-to-enforce": true,
1326	      "safe-to-redistribute": true,
1327	      "incomprehensible": false
1328	   }

1330	4.2.1.  UTCWindow

1332	   A UTCWindow object describes a time range in UTC or UTC and a zone
1333	   offset that can be applied by a TimePolicy.

1335	      Property: start

1337	         Description: The start time of the window.

1339	         Type: Internet date and time as defined in [RFC3339].

1341	         Mandatory-to-Specify: Yes.

1343	      Property: end

1345	         Description: The end time of the window.

1347	         Type: Internet date and time as defined in [RFC3339].

1349	         Mandatory-to-Specify: Yes.

1351	   Example UTCWindow object that describes a time window from 02:30
1352	   01/01/2000 UTC to 04:30 01/01/2000 UTC:

1354	   {
1355	     "start": 2000-01-01T02:30:00.00Z,
1356	     "end": 2000-01-01T04:30:00.00Z,
1357	   }

1359	   Example UTCWindow object that describes a time window in New York
1360	   time zone offset UTC-05:00 from 02:30 01/01/2000 to 04:30 01/01/2000:

1362	   {
1363	     "start": 2000-01-01T02:30:00.00-05:00,
1364	     "end": 2000-01-01T04:30:00.00-05:00,
1365	   }

1367	4.2.2.  LocalTimeWindow

1369	   A LocalTimeWindow object describes a time range in local time.  The
1370	   reader of this object MUST interpret it as "the local time at the
1371	   location of execution".  For example, if the time window states 2AM
1372	   to 4AM local time then a dCDN that has presence in both London (UTC)
1373	   and New York (UTC-05:00) will execute the trigger at 2AM-4AM UTC in
1374	   London and at 2AM-4AM UTC-05:00 in New York.

1376	      Property: start

1378	         Description: The start time of the window.

1380	         Type: JSON string formatted as DateLocalTime as defined in
1381	         Section 4.2.3.

1383	         Mandatory-to-Specify: Yes.

1385	      Property: end

1387	         Description: The end time of the window.

1389	         Type: JSON string formatted as DateLocalTime as defined in
1390	         Section 4.2.3.

1392	         Mandatory-to-Specify: Yes.

1394	   Example LocalTimeWindow object that describes a local time window
1395	   from 02:30 01/01/2000 to 04:30 01/01/2000.

1397	   {
1398	     "start": 2000-01-01T02:30:00.00,
1399	     "end": 2000-01-01T04:30:00.00,
1400	   }

1402	4.2.3.  DateLocalTime

1404	   DateLocalTime is a timestamp that follows the date and local time
1405	   notation in Section 4.3.2 of [ISO8601] as a complete date and time
1406	   extended representation, where the time zone designator is omitted.
1407	   In addition, for simplicity and as exact accuracy is not an objective
1408	   in this case, this specification does not support the decimal
1409	   fractions of seconds, and does not take leap second into
1410	   consideration.

1412	   Type: JSON string using the format "date-local-time" as defined in
1413	   Section 4.2.3.1.

1415	4.2.3.1.  Date and Local Time Format

1417	   The Date and Local Time format is specified here using the syntax
1418	   description notation defined in [ABNF].

1420	   date-fullyear   = 4DIGIT
1421	   date-month      = 2DIGIT  ; 01-12
1422	   date-mday       = 2DIGIT  ; 01-28, 01-29, 01-30, 01-31 based on
1423	                             ; month/year
1424	   time-hour       = 2DIGIT  ; 00-23
1425	   time-minute     = 2DIGIT  ; 00-59
1426	   time-second     = 2DIGIT  ; 00-59 leap seconds are not supported

1428	   local-time      = time-hour ":" time-minute ":" time-second
1429	   full-date       = date-fullyear "-" date-month "-" date-mday
1430	   date-local-time = full-date "T" local-time

1432	   Example time representing 09:00AM on 01/01/2000 local time:

1434	   2000-01-01T09:00:00.00

1436	      NOTE: Per [ABNF] and [ISO8601], the "T" character in this syntax
1437	      may alternatively be lower case "t".  For simplicity, Applications
1438	      that generate the "date-local-time" format defined here, SHOULD
1439	      only use the upper case letter "T".

1441	4.2.3.2.  Restrictions

1443	   The grammar element date-mday represents the day number within the
1444	   current month.  The maximum value varies based on the month and year
1445	   as follows:

1447	   Month Number  Month/Year           Maximum value of date-mday
1448	   ------------  ----------           --------------------------
1449	   01            January              31
1450	   02            February, normal     28
1451	   02            February, leap year  29
1452	   03            March                31
1453	   04            April                30
1454	   05            May                  31
1455	   06            June                 30
1456	   07            July                 31
1457	   08            August               31
1458	   09            September            30
1459	   10            October              31
1460	   11            November             30
1461	   12            December             31

1463	   See Appendix C of [RFC3339] for a sample C code that determines if a
1464	   year is a leap year.

1466	   The grammar element time-second may have the values 0-59.  The value
1467	   of 60 that is used in [ISO8601] to represent a leap second MUST NOT
1468	   be used.

1470	   Although [ISO8601] permits the hour to be "24", this profile of
1471	   [ISO8601] only allows values between "00" and "23" for the hour in
1472	   order to reduce confusion.

1474	5.  Footprint and Capabilities

1476	   This section covers the FCI objects required for advertisement of the
1477	   extensions and properties introduced in this document.

1479	5.1.  CI/T Versions Capability Object

1481	   The CI/T versions capability object is used to indicate support for
1482	   one or more CI/T objects versions.  Note that the default version as
1483	   originally defined in [RFC8007] MUST be implicitly supported
1484	   regardless of the versions listed in this capability object.

1486	      Property: versions

1488	         Description: A list of version numbers.

1490	         Type: An array of JSON strings

1492	         Mandatory-to-Specify: No.  The default is version 1.  A missing
1493	         or an empty versions list means that only version 1 of the
1494	         interface and objects is supported.

1496	5.1.1.  CI/T Versions Capability Object Serialization

1498	   The following shows an example of CI/T Versions Capability object
1499	   serialization for a dCDN that supports versions 2 and 2.1 of the CI/T
1500	   interface.

1502	   {
1503	    "capabilities": [
1504	      {
1505	        "capability-type": "FCI.TriggerVersion",
1506	        "capability-value": {
1507	          "versions": [ "1", "2", "2.1" ]
1508	        },
1509	        "footprints": [
1510	          <Footprint objects>
1511	        ]
1512	      }
1513	    ]
1514	   }

1516	5.2.  CI/T Playlist Protocol Capability Object

1518	   The CI/T Playlist Protocol capability object is used to indicate
1519	   support for one or more MediaProtocol types listed in Section 6.3 by
1520	   the playlists property of the "trigger.v2" object.

1522	      Property: media-protocols

1524	         Description: A list of media protocols.

1526	         Type: A list of MediaProtocol (from the CDNI Triggers media
1527	         protocol types Section 6.3)

1529	         Mandatory-to-Specify: No.  The default, in case of a missing or
1530	         an empty list, is none supported.

1532	5.2.1.  CI/T Playlist Protocol Capability Object Serialization

1534	   The following shows an example of CI/T Playlist Protocol Capability
1535	   object serialization for a dCDN that supports "hls" and "dash".

1537	   {
1538	    "capabilities": [
1539	      {
1540	        "capability-type": "FCI.TriggerPlaylistProtocol",
1541	        "capability-value": {
1542	          "media-protocols": ["hls", "dash"]
1543	        },
1544	        "footprints": [
1545	          <Footprint objects>
1546	        ]
1547	      }
1548	    ]
1549	   }

1551	5.3.  CI/T Trigger Extension Capability Object

1553	   The CI/T Generic Extension capability object is used to indicate
1554	   support for one or more GenericExtensionObject types.

1556	      Property: trigger-extension

1558	         Description: A list of supported CDNI CI/T
1559	         GenericExtensionObject types.

1561	         Type: List of strings corresponding to entries from the "CDNI
1562	         Payload Types" registry [RFC7736] that are under the CIT
1563	         namespace, and that correspond to CDNI CI/T
1564	         GenericExtensionObject objects.

1566	         Mandatory-to-Specify: No.  The default, in case of a missing or
1567	         an empty list, MUST be interpreted as "no
1568	         GenericExtensionObject types are supported".  A non-empty list
1569	         MUST be interpreted as containing "the only
1570	         GenericExtensionObject types that are supported".

1572	5.3.1.  CI/T Trigger Extension Capability Object Serialization

1574	   The following shows an example of CI/T Trigger Extension Capability
1575	   object serialization for a dCDN that supports the
1576	   "CIT.LocationPolicy" and the "CIT.TimePolicy" objects.

1578	   {
1579	    "capabilities": [
1580	      {
1581	        "capability-type": "FCI.TriggerGenericExtension",
1582	        "capability-value": {
1583	          "trigger-extension": ["CIT.LocationPolicy", "CIT.TimePolicy"]
1584	        },
1585	        "footprints": [
1586	          <Footprint objects>
1587	        ]
1588	      }
1589	    ]
1590	   }

1592	6.  IANA Considerations

1594	6.1.  CDNI Payload Types

1596	   This document requests the registration of the following CDNI Payload
1597	   Types under the IANA CDNI Payload Type registry defined in [RFC7736]:

1599	              +-----------------------------+---------------+
1600	              | Payload Type                | Specification |
1601	              +-----------------------------+---------------+
1602	              | ci-trigger-command.v2       | RFCthis       |
1603	              | ci-trigger-status.v2        | RFCthis       |
1604	              | CIT.LocationPolicy          | RFCthis       |
1605	              | CIT.TimePolicy              | RFCthis       |
1606	              | FCI.TriggerVersion          | RFCthis       |
1607	              | FCI.TriggerPlaylistProtocol | RFCthis       |
1608	              | FCI.TriggerGenericExtension | RFCthis       |
1609	              +-----------------------------+---------------+

1611	   [RFC Editor: Please replace RFCthis with the published RFC number for
1612	   this document.]

1614	6.1.1.  CDNI ci-trigger-command.v2 Payload Type

1616	   Purpose: The purpose of this payload type is to distinguish version 2
1617	   of the CI/T command (and any associated capability advertisement)

1619	   Interface: CI/T

1621	   Encoding: see Section 3.1

1623	6.1.2.  CDNI ci-trigger-status.v2 Payload Type

1625	   Purpose: The purpose of this payload type is to distinguish version 2
1626	   of the CI/T status resource response (and any associated capability
1627	   advertisement)

1629	   Interface: CI/T

1631	   Encoding: see Section 3.1

1633	6.1.3.  CDNI CI/T LocationPolicy Trigger Extension Type

1635	   Purpose: The purpose of this Trigger Extension type is to distinguish
1636	   LocationPolicy CIT Trigger Extension objects.

1638	   Interface: CI/T

1640	   Encoding: see Section 4.1

1642	6.1.4.  CDNI CI/T TimePolicy Trigger Extension Type

1644	   Purpose: The purpose of this Trigger Extension type is to distinguish
1645	   TimePolicy CI/T Trigger Extension objects.

1647	   Interface: CI/T

1649	   Encoding: see Section 4.2

1651	6.1.5.  CDNI FCI CI/T Versions Payload Type

1653	   Purpose: The purpose of this payload type is to distinguish FCI
1654	   advertisement objects for CI/T Triggers Versions objects

1656	   Interface: FCI

1658	   Encoding: see Section 5.1.1

1660	6.1.6.  CDNI FCI CI/T Playlist Protocol Payload Type

1662	   Purpose: The purpose of this payload type is to distinguish FCI
1663	   advertisement objects for CI/T Playlist Protocol objects

1665	   Interface: FCI

1667	   Encoding: see Section 5.2.1

1669	6.1.7.  CDNI FCI CI/T Extension Objects Payload Type

1671	   Purpose: The purpose of this payload type is to distinguish FCI
1672	   advertisement objects for CI/T Extension objects

1674	   Interface: FCI

1676	   Encoding: see Section 5.3.1

1678	6.2.  CDNI CI/T Trigger Error Codes types

1680	   The IANA is requested to update the "CDNI CI/T Error Codes"
1681	   subregistry (defined in Section 7.3 of [RFC8007] and located at
1682	   <https://www.iana.org/assignments/cdni-parameters>) with the
1683	   following registration:

1685	   +------------+-----------------------------------+------------------+
1686	   | Error Code | Description                       | Specification    |
1687	   +------------+-----------------------------------+------------------+
1688	   | eextension | The dCDN failed to parse a        | Section Section  |
1689	   |            | generic extension object, or does | 3.3.7 of this    |
1690	   |            | not support this extension.       | document.        |
1691	   +------------+-----------------------------------+------------------+

1693	6.3.  CDNI Media protocol types

1695	   The IANA is requested to create a new "CDNI MediaProtocol Types"
1696	   subregistry in the "Content Delivery Networks Interconnection (CDNI)
1697	   Parameters" registry.  The "CDNI Media Protocol Types" namespace
1698	   defines the valid Media Protocol object values in
1699	   Section Section 3.3.4, used by the Playlist object.  Additions to the
1700	   MediaProtocol namespace conform to the "Specification Required"
1701	   policy as defined in Section 4.6 of [RFC8126], where the
1702	   specification defines the MediaProtocol Type and the protocol to
1703	   which it is associated.  The designated expert will verify that new
1704	   protocol definitions do not duplicate existing protocol definitions
1705	   and prevent gratuitous additions to the namespace.

1707	   The following table defines the initial MediaProtocol values
1708	   corresponding to the HLS, MSS, and DASH protocols:

1710	   +---------------+-------------------+---------------+---------------+
1711	   | MediaProtocol | Description       | Specification | Protocol      |
1712	   | Type          |                   |               | Specification |
1713	   +---------------+-------------------+---------------+---------------+
1714	   | hls           | HTTP Live         | RFCthis       | RFC 8216      |
1715	   |               | Streaming         |               | [RFC8216]     |
1716	   | mss           | Microsoft Smooth  | RFCthis       | MSS [MSS]     |
1717	   |               | Streaming         |               |               |
1718	   | dash          | Dynamic Adaptive  | RFCthis       | MPEG-DASH     |
1719	   |               | Streaming over    |               | [MPEG-DASH]   |
1720	   |               | HTTP (MPEG-DASH)  |               |               |
1721	   +---------------+-------------------+---------------+---------------+

1723	   [RFC Editor: Please replace RFCthis with the published RFC number for
1724	   this document.]

1726	7.  Security Considerations

1728	   All security considerations listed in Section 8 of [RFC8007] and
1729	   Section 7 of [RFC8008] apply to this document as well.

1731	   This document defines the capability to use regular expression within
1732	   the trigger spec for more granular content selection.  The usage of
1733	   regex introduced the risk of regex complexity attacks, a.k.a ReDos
1734	   attacks.  An attacker may be able to craft a regular expression that
1735	   can exhaust server resources and may take exponential time in the
1736	   worst case.  An implementation MUST protect itself by at least accept
1737	   triggers only from an authenticated party over a secured connection.
1738	   An implementation SHOULD also protect itself by using secure
1739	   programing techniques and decline trigger commands that use
1740	   potentially risky regex, such techniques are readily available in
1741	   secure programming literature and are beyond the scope of this
1742	   document.

1744	8.  Acknowledgments

1746	   TBD

1748	9.  Contributors

1750	   The authors would like to thank all members of the "Streaming Video
1751	   Alliance" (SVA) Open Caching Working Group for their contribution in
1752	   support of this document.

1754	10.  References

1756	10.1.  Normative References

1758	   [ABNF]     Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
1759	              Specifications: ABNF", STD 68, RFC 5234,
1760	              DOI 10.17487/RFC5234, January 2008,
1761	              <https://www.rfc-editor.org/info/rfc5234>.

1763	   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
1764	              Requirement Levels", BCP 14, RFC 2119,
1765	              DOI 10.17487/RFC2119, March 1997,
1766	              <https://www.rfc-editor.org/info/rfc2119>.

1768	   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
1769	              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
1770	              <https://www.rfc-editor.org/info/rfc3339>.

1772	   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
1773	              Resource Identifier (URI): Generic Syntax", STD 66,
1774	              RFC 3986, DOI 10.17487/RFC3986, January 2005,
1775	              <https://www.rfc-editor.org/info/rfc3986>.

1777	   [RFC8006]  Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
1778	              "Content Delivery Network Interconnection (CDNI)
1779	              Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
1780	              <https://www.rfc-editor.org/info/rfc8006>.

1782	   [RFC8007]  Murray, R. and B. Niven-Jenkins, "Content Delivery Network
1783	              Interconnection (CDNI) Control Interface / Triggers",
1784	              RFC 8007, DOI 10.17487/RFC8007, December 2016,
1785	              <https://www.rfc-editor.org/info/rfc8007>.

1787	   [RFC8008]  Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
1788	              R., and K. Ma, "Content Delivery Network Interconnection
1789	              (CDNI) Request Routing: Footprint and Capabilities
1790	              Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
1791	              <https://www.rfc-editor.org/info/rfc8008>.

1793	   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
1794	              Writing an IANA Considerations Section in RFCs", BCP 26,
1795	              RFC 8126, DOI 10.17487/RFC8126, June 2017,
1796	              <https://www.rfc-editor.org/info/rfc8126>.

1798	   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
1799	              Interchange Format", STD 90, RFC 8259,
1800	              DOI 10.17487/RFC8259, December 2017,
1801	              <https://www.rfc-editor.org/info/rfc8259>.

1803	10.2.  Informative References

1805	   [ISO8601]  ISO, "Data elements and interchange formats -- Information
1806	              interchange -- Representation of dates and times",
1807	              ISO 8601:2004, Edition 3, 12 2004,
1808	              <https://www.iso.org/standard/40874.html>.

1810	   [MPEG-DASH]
1811	              ISO, "Information technology -- Dynamic adaptive streaming
1812	              over HTTP (DASH) -- Part 1: Media presentation description
1813	              and segment format", ISO/IEC 23009-1:2014, Edition 2, 05
1814	              2014, <https://www.iso.org/standard/65274.html>.

1816	   [MSS]      Microsoft, "[MS-SSTR]: Smooth Streaming Protocol",
1817	              Protocol Revision 8.0, September 2017,
1818	              <https://msdn.microsoft.com/en-us/library/ff469518.aspx>.

1820	   [PCRE841]  Hazel, P., "Perl Compatible Regular Expressions",
1821	              Version 8.41, July 2017, <http://www.pcre.org/>.

1823	   [RFC6707]  Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
1824	              Distribution Network Interconnection (CDNI) Problem
1825	              Statement", RFC 6707, DOI 10.17487/RFC6707, September
1826	              2012, <https://www.rfc-editor.org/info/rfc6707>.

1828	   [RFC7736]  Ma, K., "Content Delivery Network Interconnection (CDNI)
1829	              Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
1830	              December 2015, <https://www.rfc-editor.org/info/rfc7736>.

1832	   [RFC8216]  Pantos, R., Ed. and W. May, "HTTP Live Streaming",
1833	              RFC 8216, DOI 10.17487/RFC8216, August 2017,
1834	              <https://www.rfc-editor.org/info/rfc8216>.

1836	Authors' Addresses

1838	   Ori Finkelman
1839	   Qwilt
1840	   6, Ha'harash
1841	   Hod HaSharon  4524079
1842	   Israel

1844	   Phone: +972-72-2221647
1845	   Email: ori.finkelman.ietf@gmail.com
1846	   Sanjay Mishra
1847	   Verizon
1848	   13100 Columbia Pike
1849	   Silver Spring, MD  20904
1850	   USA

1852	   Email: sanjay.mishra@verizon.com