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2	Network Working Group                                       O. Finkelman
3	Internet-Draft                                                     Qwilt
4	Intended status: Standards Track                               S. Mishra
5	Expires: April 25, 2019                                          Verizon
6	                                                        October 22, 2018

8	               CDNI Control Triggers Interface Extensions
9	            draft-finkelman-cdni-triggers-sva-extensions-01

11	Abstract

13	   The Open Caching working group of the Streaming Video Alliance is
14	   focused on the delegation of video delivery request from commercial
15	   CDNs to a caching layer at the ISP.  In that aspect, Open Caching is
16	   a specific use case of CDNI, where the commercial CDN is the upstream
17	   CDN (uCDN) and the ISP caching layer is the downstream CDN (dCDN).
18	   The extensions specified in this document to the CDNI CI/T interface
19	   are derived from requirements raised by Open Caching but are
20	   applicable to CDNI use cases in general.

22	Requirements Language

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

28	Status of This Memo

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

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

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

43	   This Internet-Draft will expire on April 25, 2019.

45	Copyright Notice

47	   Copyright (c) 2018 IETF Trust and the persons identified as the
48	   document authors.  All rights reserved.

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

60	Table of Contents

62	   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
63	     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
64	   2.  Interfaces Extensions Overview  . . . . . . . . . . . . . . .   4
65	     2.1.  CDNI Control Interface / Triggers Extensions  . . . . . .   4
66	       2.1.1.  CI/T Objects  . . . . . . . . . . . . . . . . . . . .   4
67	       2.1.2.  Trigger Specification . . . . . . . . . . . . . . . .   4
68	       2.1.3.  Content Selection . . . . . . . . . . . . . . . . . .   4
69	       2.1.4.  Trigger Extensibility . . . . . . . . . . . . . . . .   5
70	       2.1.5.  Error Propagation . . . . . . . . . . . . . . . . . .   5
71	     2.2.  CDNI Footprint and Capabilities Interface Extensions  . .   6
72	   3.  CI/T Version 2  . . . . . . . . . . . . . . . . . . . . . . .   6
73	     3.1.  CI/T Objects V2 . . . . . . . . . . . . . . . . . . . . .   6
74	     3.2.  Properties of CI/T Version 2 objects  . . . . . . . . . .   9
75	       3.2.1.  Trigger Specification Version 2 . . . . . . . . . . .   9
76	       3.2.2.  RegexMatch  . . . . . . . . . . . . . . . . . . . . .  10
77	       3.2.3.  Playlist  . . . . . . . . . . . . . . . . . . . . . .  12
78	       3.2.4.  MediaProtocol . . . . . . . . . . . . . . . . . . . .  13
79	       3.2.5.  CI/T Trigger Extensions . . . . . . . . . . . . . . .  13
80	         3.2.5.1.  Enforcement Options . . . . . . . . . . . . . . .  13
81	         3.2.5.2.  GenericExtensionObject  . . . . . . . . . . . . .  16
82	       3.2.6.  Error Description Version 2 . . . . . . . . . . . . .  18
83	       3.2.7.  Error codes . . . . . . . . . . . . . . . . . . . . .  19
84	   4.  Trigger Extension Objects . . . . . . . . . . . . . . . . . .  19
85	     4.1.  LocationPolicy extension  . . . . . . . . . . . . . . . .  19
86	     4.2.  TimePolicy Extension  . . . . . . . . . . . . . . . . . .  21
87	   5.  Footprint and Capabilities  . . . . . . . . . . . . . . . . .  23
88	     5.1.  CI/T Versions Capability Object . . . . . . . . . . . . .  23
89	       5.1.1.  CI/T Versions Capability Object Serialization . . . .  24
90	     5.2.  CI/T Playlist Protocol Capability Object  . . . . . . . .  24
91	       5.2.1.  CI/T Playlist Protocol Capability Object
92	               Serialization . . . . . . . . . . . . . . . . . . . .  24

94	     5.3.  CI/T Trigger Extension Capability Object  . . . . . . . .  25
95	       5.3.1.  CI/T Trigger Extension Capability Object
96	               Serialization . . . . . . . . . . . . . . . . . . . .  25
97	   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  26
98	     6.1.  CDNI Payload Types  . . . . . . . . . . . . . . . . . . .  26
99	       6.1.1.  CDNI ci-trigger-command.v2 Payload Type . . . . . . .  26
100	       6.1.2.  CDNI ci-trigger-status.v2 Payload Type  . . . . . . .  27
101	       6.1.3.  CDNI CI/T LocationPolicy Trigger Extension Type . . .  27
102	       6.1.4.  CDNI CI/T TimePolicy Trigger Extension Type . . . . .  27
103	       6.1.5.  CDNI FCI CI/T Versions Payload Type . . . . . . . . .  27
104	       6.1.6.  CDNI FCI CI/T Playlist Protocol Payload Type  . . . .  27
105	       6.1.7.  CDNI FCI CI/T Extension Objects Payload Type  . . . .  28
106	     6.2.  CDNI CI/T Trigger Error Codes types . . . . . . . . . . .  28
107	     6.3.  CDNI Media protocol types . . . . . . . . . . . . . . . .  28
108	   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  29
109	   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  29
110	   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  29
111	   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  30
112	     10.1.  Normative References . . . . . . . . . . . . . . . . . .  30
113	     10.2.  Informative References . . . . . . . . . . . . . . . . .  30
114	   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  31

116	1.  Introduction

118	   This document defines the objects and extensions required for
119	   granular content management operations.  For that purpose it extends
120	   CDNI Control Interface/Triggers [RFC8007].  The basic operations are
121	   the ones defined in the RFC (i.e. purge, invalidate, pre-position).
122	   For consistency, this document follows the CDNI notation of uCDN (the
123	   commercial CDN) and dCDN (the ISP caching layer).  When using the
124	   term CP in this document we refer to a video content provider.

126	   The CDNI metadata interface is described in [RFC8006].

128	   The CDNI footprint and capability interface is described in
129	   [RFC8008].

131	   The CDNI control interface / triggers is described in [RFC8007].

133	1.1.  Terminology

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

138	   Additionally, the following terms are used throughout this document
139	   and are defined as follows:

141	   o  HLS - HTTP Live Streaming
142	   o  DASH - Dynamic Adaptive Streaming Over HTTP

144	   o  MSS - Microsoft Smooth Streaming

146	2.  Interfaces Extensions Overview

148	   This document defines extensions for the CDNI Control Interface /
149	   Triggers [RFC8007] and defines FCI objects as per the CDNI Footprint
150	   and Capabilities Interface [RFC8008].

152	2.1.  CDNI Control Interface / Triggers Extensions

154	2.1.1.  CI/T Objects

156	   This document specifies version 2 of the CI/T objects in order to
157	   support version 2 of the Trigger Specification as required below in
158	   Section 2.1.2.

160	2.1.2.  Trigger Specification

162	   This document specifies version 2 of the Trigger Specification which
163	   is an enhancement of the Trigger Specification that includes all
164	   properties as defined in section 5.2.1 of [RFC8007] as well as the
165	   additional properties required by the use cases listed below in
166	   Section 2.1.3 and Section 2.1.4.

168	2.1.3.  Content Selection

170	   The trigger specification as defined in section 5.2.1 of [RFC8007]
171	   provides means to select content objects by matching a full content
172	   URL or patterns with wildcards.  This document specifies two
173	   additional selection options.

175	   o  Regular Expression - Using regex a uCDN can create more complex
176	      rules to select the content objects for the cases of invalidation
177	      and purge.  For example, purging specific content within a
178	      specific directory path.

180	   o  Content Playlist - Using video playlist files, a uCDN can trigger
181	      an operation that will be applied to a collection of distinct
182	      media files in a format that is natural for a streaming video
183	      content provider.  A playlist may have several formats,
184	      specifically HTTP Live Streaming (HLS) *.m3u8 manifest [RFC8216],
185	      Microsoft Smooth Streaming (MSS) *.ismc client manifest [MSS], and
186	      Dynamic Adaptive Streaming over HTTP (DASH) *.mpd file [ISO/IEC
187	      23009-1:2014] [MPEG-DASH].

189	2.1.4.  Trigger Extensibility

191	   The CDNI Control Interface / Triggers [RFC8007] defines a set of
192	   objects used by the trigger commands.  In order to have better
193	   control and finer granularity, we define a mechanism for generic
194	   trigger extension object wrapper for managing individual CDNI trigger
195	   extensions in an opaque manner, as well as an initial set of trigger
196	   extension objects.

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

201	   o  CIT.LocationPolicy (for controlling the locations in which the
202	      trigger is executed)

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

207	   Example use cases

209	   o  Pre-position with cache location policy

211	   o  Purge content with cache location policy

213	   o  Pre-position at a specific time

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

218	2.1.5.  Error Propagation

220	   As triggers may be propagated over a chain of downstream CDNs and
221	   since, in some cases, triggers may be redistributed from dCDN-A to
222	   dCDN-B even if dCDN-A does not understand a specific extension, it is
223	   essential for the uCDN that sets the trigger to be able to trace back
224	   and error to the downstream where it occurred.  This document
225	   specifies version 2 of the Error Description which is an enhancement
226	   of the Error Description as defined in section 5.2.6 of [RFC8007] and
227	   that includes all the original properties as well as the additional
228	   property "cdn" which is an identifier for the faulty CDN.  When a
229	   downstream dCDN-A propagates a trigger to another downstream dCDN-B,
230	   it MUST also propagate back the errors received in the trigger status
231	   resource from dCDN-B.  This makes sure that the trigger originating
232	   upstream CDN will receive an array of errors that occurred in all the
233	   CDNs along the execution path, each error carrying its own CDN
234	   identifier.

236	2.2.  CDNI Footprint and Capabilities Interface Extensions

238	   Extending the trigger mechanism with optional properties requires the
239	   ability for the dCDN to advertise which optional properties it
240	   supports.

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

247	   Example use cases

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

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

262	   o  Trigger extensions: Advertise which trigger extensions object
263	      types are supported by the dCDN.

265	3.  CI/T Version 2

267	   [RFC8007] does not define a version number and versioning scheme.
268	   We, therefore, designate the interface and objects as defined in
269	   section 5 of [RFC8007] as version 1.  The following sections define
270	   version 2 of the CI/T objects and their properties as extensions of
271	   version 1.

273	3.1.  CI/T Objects V2

275	   Version 2 of the CI/T interface requires the support of the following
276	   objects:

278	   o  CI/T Commands v2: A trigger command request using the payload type
279	      ci-trigger-command.v2.  Version 2 MUST only use "trigger.v2"
280	      objects as defined in Section 3.2.1, instead of "trigger" objects.
281	      All other properties of the trigger command v2 are as defined in
282	      section 5.1.1 of [RFC8007].

284	   o  Trigger Status Resource v2: A trigger status resource response
285	      using the payload type ci-trigger-status.v2.  Version 2 MUST only
286	      use "trigger.v2" objects as defined in Section 3.2.1, instead of a
287	      "trigger" object, as well as "errors.v2" objects as defined in
288	      Section 3.2.6, instead of a "errors" object All other properties
289	      of the trigger status v2 are as defined in section 5.1.2 of
290	      [RFC8007].  The errors array "errors.v2" is a list of all errors
291	      that occurred in any of the downstream CDNs along the execution
292	      path.  When a downstream CDN, dCDN-A, propagates a trigger to
293	      another downstream CDN, dCDN-B, it MUST also propagated back all
294	      errors reported by dCDN-B in the trigger status resource and add
295	      them to its own trigger status resource.

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

300	   Usage example of version 2 of trigger command
301	     REQUEST:

303	         POST /triggers HTTP/1.1
304	         User-Agent: example-user-agent/0.1
305	         Host: triggers.dcdn.example.com
306	         Accept: */*
307	         Content-Type: application/cdni; ptype=ci-trigger-command.v2
308	         {
309	           "trigger.v2": { <properties of a trigger.v2 object> },
310	           "cdn-path": [ "AS64496:1" ]
311	         }

313	     RESPONSE:

315	         HTTP/1.1 201 Created
316	         Date: Wed, 04 May 2016 08:48:10 GMT
317	         Content-Length: 467
318	         Content-Type: application/cdni; ptype=ci-trigger-status.v2
319	         Location: https://triggers.dcdn.example.com/triggers/0
320	         Server: example-server/0.1

322	         {
323	            "errors.v2": [ { <properties of 1st error.v2 object> },
324	                             ...,
325	                           { <properties of Nth error.v2 object> }
326	            ],
327	            "ctime": 1462351690,
328	            "etime": 1462351698,
329	            "mtime": 1462351690,
330	            "status": "pending",
331	            "trigger.v2": { <properties of a trigger.v2 object> }
332	         }

334	   Usage example of version 2 of trigger status for the trigger created
335	   in the above trigger command example:

337	     REQUEST:

339	         GET /triggers/0 HTTP/1.1
340	         User-Agent: example-user-agent/0.1
341	         Host: triggers.dcdn.example.com
342	         Accept: */*

344	     RESPONSE:

346	         HTTP/1.1 200 OK
347	         Content-Length: 467
348	         Expires: Wed, 04 May 2016 08:49:10 GMT
349	         Server: example-server/0.1
350	         ETag: "6990548174277557683"
351	         Cache-Control: max-age=60
352	         Date: Wed, 04 May 2016 08:48:10 GMT
353	         Content-Type: application/cdni; ptype=ci-trigger-status.v2

355	         {
356	            "errors.v2": [ { <properties of 1st error.v2 object> },
357	                             ...,
358	                           { <properties of Nth error.v2 object> }
359	            ],
360	            "ctime": 1462351690,
361	            "etime": 1462351698,
362	            "mtime": 1462351690,
363	            "status": "pending",
364	            "trigger.v2": { <properties of a trigger.v2 object> }
365	         }

367	3.2.  Properties of CI/T Version 2 objects

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

372	3.2.1.  Trigger Specification Version 2

374	   Version 2 of the Trigger Specification adds the following properties
375	   on top of the existing properties of the trigger specification
376	   defined in section 5.2.1 of [RFC8007].

378	      Property: content.regexs

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

383	         Type: A JSON array of RegexMatch objects (see Section 3.2.2).

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

388	      Property: content.playlists

390	         Description: Playlists of content the CI/T trigger command
391	         applies to.

393	         Type: A JSON array of Playlist objects (see Section 3.2.3).

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

398	      Property: extensions

400	         Description: Array of trigger extension data.

402	         Type: Array of GenericTriggerExtension objects (see
403	         Section 3.2.5.2).

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

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

410	     {
411	       "trigger.v2": {
412	         "type": "invalidate",
413	         "content.regexs": [ <list of RegexMatch objects> ],
414	         "content.playlists": [ <list of Playlist objects> ],
415	         "extensions": [ <list of GenericTriggerExtension objects ]
416	       },
417	       "cdn-path": [ "AS64496:1" ]
418	     }

420	3.2.2.  RegexMatch

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

426	      Property: regex

428	         Description: A regular expression for URI matching.

430	         Type: A regular expression to match against the URI, i.e
431	         against the path-absolute and the query string parameters

433	         [RFC3986].  The regular expression string MUST be compatible
434	         with PCRE [PCRE841].

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

440	         Mandatory: Yes.

442	      Property: case-sensitive

444	         Description: Flag indicating whether or not case-sensitive
445	         matching should be used.

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

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

453	      Property: match-query-string

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

458	         Type: JSON boolean.  Either "true" (the full URI, including the
459	         query part, should be compared against the regex) or "false"
460	         (the query part of the URI should be dropped before comparison
461	         with the given regex).

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

468	   Example of a case sensitive, no query parameters, regex match
469	   against:
470	   "^(https:\/\/video\.example\.com)\/([a-z])\/movie1\/([1-7])\/*(index.
471	   m3u8|\d{3}.ts)$".

473	   This regex matches URLs of domain video.example.com where the path
474	   structure is /(single lower case letter)/(name-of-title)/(single
475	   digit between 1 to 7)/(index.m3u8 or a 3 digit number with ts
476	   extension).  For example: https://video.example.com/d/movie1/5/
477	   index.m3u8 or https://video.example.com/k/movie1/4/013.ts.

479	     {
480	      "regex": "^(https:\\/\\/video\\.example\\.com)\\/([a-z])\\/movie1\
481	                \/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
482	      "case-sensitive": true,
483	      "match-query-string": false
484	     }

486	3.2.3.  Playlist

488	   A Playlist consists of a full URL and a media protocol identifier.
489	   An implementation that supports a specific playlist media protocol
490	   MUST be able to parse playlist files of that protocol type and
491	   extract, possibly recursively, the URLs to all media objects and/or
492	   sub playlist files, and apply the trigger to each one of them
493	   separately.

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

497	      Property: playlist

499	         Description: A URL to the playlist file.

501	         Type: A URL represented as a JSON string.

503	         Mandatory: Yes.

505	      Property: media-protocol

507	         Description: Media protocol to be when parsing and interpreting
508	         this playlist.

510	         Type: MediaProtocol (see Section 3.2.4).

512	         Mandatory: Yes.

514	   Example of a HLS playlist:

516	     {
517	      "playlist": "https://www.example.com/hls/title/index.m3u8",
518	      "media-protocol": "hls"
519	     }

521	3.2.4.  MediaProtocol

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

527	   Type: JSON string

529	   Example:

531	   "dash"

533	3.2.5.  CI/T Trigger Extensions

535	   A "trigger.v2" object, as defined in Section 3.2.1 includes an
536	   optional array of trigger extension objects.  A trigger extension
537	   contain properties that are used as directives for dCDN when
538	   executing the trigger command -- for example, location policies, time
539	   policies and so on.  Each such CDNI Trigger extension is a
540	   specialization of a CDNI GenericTriggerExtension object.  The
541	   GenericTriggerExtension object abstracts the basic information
542	   required for trigger distribution from the specifics of any given
543	   property (i.e., property semantics, enforcement options, etc.).  All
544	   trigger extensions are optional, and it is thus the responsibility of
545	   the extension specification to define a consistent default behavior
546	   for the case the extension is not present.

548	3.2.5.1.  Enforcement Options

550	   The trigger enforcement options concept is in accordance with the
551	   metadata enforcement options as defined in section 3.2 of [RFC8006].

553	   The GenericTriggerExtension object defines the properties contained
554	   within it as well as whether or not the properties are "mandatory-to-
555	   enforce".  If the dCDN does not understand or support a mandatory-to-
556	   enforce property, the dCDN MUST NOT execute the trigger command.  If
557	   the extension is not mandatory-to-enforce, then that
558	   GenericTriggerExtension object can be safely ignored and the trigger
559	   command can be processed in accordance with the rest of the CDNI
560	   Trigger spec.

562	   Although a CDN MUST NOT execute a trigger command if a mandatory-to-
563	   enforce extension cannot be enforced, it could still be safe to
564	   redistribute that trigger (the "safe-to-redistribute" property) to
565	   another CDN without modification.  For example, in the cascaded CDN
566	   case, a transit CDN (tCDN) could convey mandatory-to-enforce trigger
567	   extension to a dCDN.  For a trigger extension that does not require
568	   customization or translation (i.e., trigger extension that is safe-
569	   to-redistribute), the data representation received off the wire MAY
570	   be stored and redistributed without being understood or supported by
571	   the tCDN.  However, for trigger extension that requires translation,
572	   transparent redistribution of the uCDN trigger values might not be
573	   appropriate.  Certain triggers extensions can be safely, though
574	   perhaps not optimally, redistributed unmodified.  For example, pre-
575	   position command might be executed in suboptimal times for some
576	   geographies if transparently redistributed, but it might still work.

578	   Redistribution safety MUST be specified for each
579	   GenericTriggerExtension property.  If a CDN does not understand or
580	   support a given GenericTriggerExtension property that is not safe-to-
581	   redistribute, the CDN MUST set the "incomprehensible" flag to true
582	   for that GenericTriggerExtension object before redistributing it.
583	   The "incomprehensible" flag signals to a dCDN that trigger metadata
584	   was not properly transformed by the tCDN.  A CDN MUST NOT attempt to
585	   execute a trigger that has been marked as "incomprehensible" by a
586	   uCDN.

588	   tCDNs MUST NOT change the value of mandatory-to-enforce or safe-to-
589	   redistribute when propagating a trigger to a dCDN.  Although a tCDN
590	   can set the value of "incomprehensible" to true, a tCDN MUST NOT
591	   change the value of "incomprehensible" from true to false.

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

598	   +-------+-------+------------+--------------------------------------+
599	   | MtE   | StR   | Extension  | Trigger action                       |
600	   |       |       | object     |                                      |
601	   |       |       | understood |                                      |
602	   |       |       | by tCDN    |                                      |
603	   +-------+-------+------------+--------------------------------------+
604	   | False | True  | True       | Can execute and redistribute.        |
605	   | False | True  | False      | Can execute and redistribute.        |
606	   | False | False | False      | Can execute. MUST set                |
607	   |       |       |            | "incomprehensible" to true when      |
608	   |       |       |            | redistributing.                      |
609	   | False | False | True       | Can execute. Can redistribute after  |
610	   |       |       |            | transforming the trigger extension   |
611	   |       |       |            | (if the CDN knows how to do so       |
612	   |       |       |            | safely); otherwise, MUST set         |
613	   |       |       |            | "incomprehensible" to true when      |
614	   |       |       |            | redistributing.                      |
615	   | True  | True  | True       | Can execute and redistribute.        |
616	   | True  | True  | False      | MUST NOT execute but can             |
617	   |       |       |            | redistribute..                       |
618	   | True  | False | True       | Can execute. Can redistribute after  |
619	   |       |       |            | transforming the trigger extension   |
620	   |       |       |            | (if the CDN knows how to do so       |
621	   |       |       |            | safely); otherwise, MUST set         |
622	   |       |       |            | "incomprehensible" to true when      |
623	   |       |       |            | redistributing.                      |
624	   | True  | False | False      | MUST NOT serve.  MUST set            |
625	   |       |       |            | "incomprehensible" to true when      |
626	   |       |       |            | redistributing.                      |
627	   +-------+-------+------------+--------------------------------------+

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

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

637	   +-------+--------+---------------+----------------------------------+
638	   | MtE   | Incomp | Extension     | Trigger action                   |
639	   |       |        | object        |                                  |
640	   |       |        | understood by |                                  |
641	   |       |        | dCDN          |                                  |
642	   +-------+--------+---------------+----------------------------------+
643	   | False | False  | True          | Can execute.                     |
644	   | False | True   | True          | Can execute but MUST NOT         |
645	   |       |        |               | interpret/apply any trigger      |
646	   |       |        |               | extension marked as              |
647	   |       |        |               | "incomprehensible".              |
648	   | False | False  | False         | Can execute.                     |
649	   | False | True   | False         | Can execute but MUST NOT         |
650	   |       |        |               | interpret/apply any trigger      |
651	   |       |        |               | extension marked as              |
652	   |       |        |               | "incomprehensible".              |
653	   | True  | False  | True          | Can execute.                     |
654	   | True  | True   | True          | MUST NOT execute.                |
655	   | True  | False  | False         | MUST NOT execute.                |
656	   | True  | True   | False         | MUST NOT execute.                |
657	   +-------+--------+---------------+----------------------------------+

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

662	3.2.5.2.  GenericExtensionObject

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

667	      Property: generic-trigger-extension-type

669	         Description: Case-insensitive CDNI Trigger extension object
670	         type.

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

676	         Mandatory-to-Specify: Yes.

678	      Property: generic-trigger-extension-value

680	         Description: CDNI Trigger extension object.

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

685	         Mandatory-to-Specify: Yes.

687	      Property: mandatory-to-enforce

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

692	         Type: Boolean

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

697	      Property: safe-to-redistribute

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

702	         Type: Boolean

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

707	      Property: incomprehensible

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

715	         Type: Boolean

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

720	   Example of a GenericTriggerExtension containing a specific trigger
721	   extension object:

723	      {
724	        "generic-trigger-extension-type":
725	          <Type of this trigger extension object>,
726	        "generic-trigger-extension-value":
727	          {
728	            <properties of this trigger extension object>
729	          },
730	        "mandatory-to-enforce": true,
731	        "safe-to-redistribute": true,
732	        "incomprehensible": false
733	      }

735	3.2.6.  Error Description Version 2

737	   Version 2 of the Error Description adds the "cdn" property on top of
738	   the existing properties of the trigger Error Description as defined
739	   in section 5.2.6 of [RFC8007].  The "cdn" property identifies the CDN
740	   in which the error have occurred.

742	      Property: cdn

744	         Description: The CDN PID of the CDN where the error occurred.

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

749	         Mandatory: Yes.

751	   Example of an errors.v2 with a an error of unsupported location
752	   policy extension object:

754	   {
755	     "errors.v2": [
756	      {
757	        "content.urls": [
758	           "https://newsite.example.com/index.html"
759	         ],
760	        "description": "unrecoginzed extension type CIT.LocationPolicy",
761	        "error": "eunsupported",
762	        "cdn": "AS64496:1"
763	      },
764	     ]
765	   }

767	3.2.7.  Error codes

769	   This document adds the error code "eextension" to the error codes
770	   table defined in section 5.2.6 of [RFC8007].  This error code
771	   designates that an error occurred while parsing a generic trigger
772	   extension, or that the specific extension is not supported by the
773	   CDN.  A CDN that fails to parse or execute a generic extension object
774	   MUST report it using the "errors.v2" array within the trigger status
775	   resource, while setting the error code to "eextension" and providing
776	   an appropriate description.  The "eextension" error code is a
777	   registered type of "CDNI CI/T Trigger Error Codes" (see Section 6.2).

779	4.  Trigger Extension Objects

781	   The objects defined below are intended to be used in the
782	   GenericTriggerExtension object's generic-trigger-extension-value
783	   field as defined in section Section 3.2.5.2, and their generic-
784	   trigger-extension-type property MUST be set to the appropriate CDNI
785	   Payload Type as defined in Section 6.1 .

787	4.1.  LocationPolicy extension

789	   A content operation may be relevant for a specific geographical
790	   region, or need to be excluded from a specific region.  In this case,
791	   the trigger should be applied only to parts of the network that are
792	   either "included" or "not excluded" by the location policy.  Note
793	   that the restrictions here are on the cache location rather than the
794	   client location.

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

799	   Example use cases:

801	   o  Pre-position: Certain contracts allow for pre-positioning or
802	      availability of contract in all regions except for certain
803	      excluded regions in the world, including caches.  For example,
804	      some content cannot ever knowingly touch servers in a specific
805	      country, including cached content.  Therefore, these regions MUST
806	      be excluded from a pre-positioning operation.

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

813	   Object specification
814	      Property: locations

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

819	         Type: Array of LocationRule objects (see Section 4.2.2.1 of
820	         [RFC8006])

822	         Mandatory-to-Specify: Yes.

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

828	   The trigger command is allowed, or denied, for a specific cache
829	   location according to the action of the first location whose
830	   footprint matches against that cache's location.  If two or more
831	   footprints overlap, the first footprint that matches against the
832	   cache's location determines the action a CDN MUST take.  If the
833	   "locations" property is an empty list or if none of the listed
834	   footprints match the location of a specific cache location, then the
835	   result is equivalent to a "deny" action.

837	   The following is an example of pre-position trigger specification
838	   with a trigger-extensions array including a location policy that
839	   allows the trigger execution in the US but blocks its execution in
840	   Canada:

842	      {
843	        "trigger": {
844	          "type": "preposition",
845	          "content.urls": [
846	              "https://www.example.com/a/b/c/1",
847	              "https://www.example.com/a/b/c/2"
848	          ],
849	          "extensions": [
850	             {
851	                "generic-trigger-extension-type": "CIT.LocationPolicy",
852	                "generic-trigger-extension-value":
853	                 {
854	                    "locations": [
855	                      {
856	                        "action": "allow",
857	                        "footprints": [
858	                          {
859	                            "footprint-type": "countrycode",
860	                            "footprint-value": ["us"]
861	                          }
862	                        ]
863	                      },
864	                      {
865	                        "action": "deny",
866	                        "footprints": [
867	                          {
868	                            "footprint-type": "countrycode",
869	                            "footprint-value": ["ca"]
870	                          }
871	                        ]
872	                      }
873	                    ]
874	                 },
875	                "mandatory-to-enforce": true,
876	                "safe-to-redistribute": true,
877	                "incomprehensible": false
878	           }
879	          ]
880	        },
881	        "cdn-path": [ "AS64496:1" ]
882	      }

884	4.2.  TimePolicy Extension

886	   A uCDN may wish to perform content management operations on the dCDN
887	   in a specific schedule.  The TimePolicy extensions allows the uCDN to
888	   instruct the dCDN to execute the trigger command in a desired time
889	   window.

891	      Example use cases

893	      *  Pre-position: A content provider wishes to pre-populate a new
894	         episode at off-peak time so that it would be ready on caches
895	         (for example home caches) at prime time when the episode is
896	         released for viewing.  A scheduled operation enables the uCDN
897	         to direct the dCDN in what time frame to execute the trigger.
898	         The time values are in UNIX epoch.

900	      *  Regional schedule: When used in combination with the Location
901	         Policy defined in Section 4.1, the uCDN can trigger separate
902	         commands for different geographical regions, for each region
903	         using a different schedule.  This allows the uCDN to control
904	         the execution time per region and, for example, direct the dCDN
905	         to execute at off-peak hours, as they are defined per region.

907	   Object specification

909	      Property: window

911	         Description: A time frame in which the trigger should be
912	         executed.

914	         Type: TimeWindow object (see Section 4.2.3.2 of [RFC8006])

916	         Mandatory-to-Specify: Yes.

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

923	   Example of trigger specification with a scheduled time window between
924	   09:00 01/01/2000 UTC and 17:00 01/01/2000 UTC:

926	      POST /triggers HTTP/1.1
927	      User-Agent: example-user-agent/0.1
928	      Host: dcdn.example.com
929	      Accept: */*
930	      Content-Type: application/cdni; ptype=ci-trigger-command
931	      Content-Length: 352

933	      {
934	        "trigger": {
935	          "type": "preposition",
936	          "content.urls": [
937	              "https://www.example.com/a/b/c/1",
938	              "https://www.example.com/a/b/c/2"
939	            ],
940	          "extensions": [
941	             {
942	                "generic-trigger-extension-type": "CIT.TimePolicy",
943	                "generic-trigger-extension-value":
944	                 {
945	                   "window": {
946	                      "start": 946717200,
947	                      "end": 946746000
948	                   }
949	                 }
950	                "mandatory-to-enforce": true,
951	                "safe-to-redistribute": true,
952	                "incomprehensible": false
953	             }
954	          ],
955	        },
956	        "cdn-path": [ "AS64496:1" ]
957	      }

959	5.  Footprint and Capabilities

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

964	5.1.  CI/T Versions Capability Object

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

971	      Property: versions

973	         Description: A list of version numbers.

975	         Type: An array of JSON strings

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

981	5.1.1.  CI/T Versions Capability Object Serialization

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

987	      {
988	        "capabilities": [
989	          {
990	            "capability-type": "FCI.TriggerVersion",
991	            "capability-value": {
992	              "versions": [ "1", "2", "2.1" ]
993	            },
994	            "footprints": [
995	              <Footprint objects>
996	            ]
997	          }
998	        ]
999	      }

1001	5.2.  CI/T Playlist Protocol Capability Object

1003	   The CI/T Playlist Protocol capability object is used to indicate
1004	   support for one or more MediaProtocols listed in Section 6.3 by the
1005	   playlists property of the "trigger.v2" object.

1007	      Property: media-protocols

1009	         Description: A list of media protocols.

1011	         Type: A list of MediaProtocol (from the CDNI Triggers media
1012	         protocol types Section 6.3)

1014	         Mandatory-to-Specify: No.  The default, in case of a missing or
1015	         an empty list, is none supported.

1017	5.2.1.  CI/T Playlist Protocol Capability Object Serialization

1019	   The following shows an example of CI/T Playlist Protocol Capability
1020	   object serialization for a dCDN that supports "hls" and "dash".

1022	      {
1023	        "capabilities": [
1024	          {
1025	            "capability-type": "FCI.TriggerPlaylistProtocol",
1026	            "capability-value": {
1027	              "media-protocols": ["hls", "dash"]
1028	            },
1029	            "footprints": [
1030	              <Footprint objects>
1031	            ]
1032	          }
1033	        ]
1034	      }

1036	5.3.  CI/T Trigger Extension Capability Object

1038	   The CI/T Generic Extension capability object is used to indicate
1039	   support for one or more GenericExtensionObject types.

1041	      Property: trigger-extension

1043	         Description: A list of supported CDNI CI/T
1044	         GenericExtensionObject types.

1046	         Type: List of strings corresponding to entries from the "CDNI
1047	         Payload Types" registry [RFC7736] that are under the CIT
1048	         namespace, and that correspond to CDNI CI/T
1049	         GenericExtensionObject objects.

1051	         Mandatory-to-Specify: No.  The default, in case of a missing or
1052	         an empty list, MUST be interpreted as "no
1053	         GenericExtensionObject types are supported".  A non-empty list
1054	         MUST be interpreted as containing "the only
1055	         GenericExtensionObject types that are supported".

1057	5.3.1.  CI/T Trigger Extension Capability Object Serialization

1059	   The following shows an example of CI/T Trigger Extension Capability
1060	   object serialization for a dCDN that supports the
1061	   "CIT.LocationPolicy" and the "CIT.TimePolicy" objects.

1063	   {
1064	     "capabilities": [
1065	       {
1066	         "capability-type": "FCI.TriggerGenericExtension",
1067	         "capability-value": {
1068	           "trigger-extension": ["CIT.LocationPolicy", "CIT.TimePolicy"]
1069	         },
1070	         "footprints": [
1071	           <Footprint objects>
1072	         ]
1073	       }
1074	     ]
1075	   }

1077	6.  IANA Considerations

1079	6.1.  CDNI Payload Types

1081	   This document requests the registration of the following CDNI Payload
1082	   Types under the IANA CDNI Payload Type registry defined in [RFC7736]:

1084	              +-----------------------------+---------------+
1085	              | Payload Type                | Specification |
1086	              +-----------------------------+---------------+
1087	              | ci-trigger-command.v2       | RFCthis       |
1088	              | ci-trigger-status.v2        | RFCthis       |
1089	              | CIT.LocationPolicy          | RFCthis       |
1090	              | CIT.TimePolicy              | RFCthis       |
1091	              | FCI.TriggerVersion          | RFCthis       |
1092	              | FCI.TriggerPlaylistProtocol | RFCthis       |
1093	              | FCI.TriggerGenericExtension | RFCthis       |
1094	              +-----------------------------+---------------+

1096	   [RFC Editor: Please replace RFCthis with the published RFC number for
1097	   this document.]

1099	6.1.1.  CDNI ci-trigger-command.v2 Payload Type

1101	   Purpose: The purpose of this payload type is to distinguish version 2
1102	   of the CI/T command (and any associated capability advertisement)

1104	   Interface: CI/T

1106	   Encoding: see Section 3.1

1108	6.1.2.  CDNI ci-trigger-status.v2 Payload Type

1110	   Purpose: The purpose of this payload type is to distinguish version 2
1111	   of the CI/T status resource response (and any associated capability
1112	   advertisement)

1114	   Interface: CI/T

1116	   Encoding: see Section 3.1

1118	6.1.3.  CDNI CI/T LocationPolicy Trigger Extension Type

1120	   Purpose: The purpose of this Trigger Extension type is to distinguish
1121	   LocationPolicy CIT Trigger Extension objects.

1123	   Interface: CI/T

1125	   Encoding: see Section 4.1

1127	6.1.4.  CDNI CI/T TimePolicy Trigger Extension Type

1129	   Purpose: The purpose of this Trigger Extension type is to distinguish
1130	   TimePolicy CI/T Trigger Extension objects.

1132	   Interface: CI/T

1134	   Encoding: see Section 4.2

1136	6.1.5.  CDNI FCI CI/T Versions Payload Type

1138	   Purpose: The purpose of this payload type is to distinguish FCI
1139	   advertisement objects for CI/T Triggers Versions objects

1141	   Interface: FCI

1143	   Encoding: see Section 5.1.1

1145	6.1.6.  CDNI FCI CI/T Playlist Protocol Payload Type

1147	   Purpose: The purpose of this payload type is to distinguish FCI
1148	   advertisement objects for CI/T Playlist Protocol objects

1150	   Interface: FCI

1152	   Encoding: see Section 5.2.1

1154	6.1.7.  CDNI FCI CI/T Extension Objects Payload Type

1156	   Purpose: The purpose of this payload type is to distinguish FCI
1157	   advertisement objects for CI/T Extension objects

1159	   Interface: FCI

1161	   Encoding: see Section 5.3.1

1163	6.2.  CDNI CI/T Trigger Error Codes types

1165	   The IANA is requested to update the "CDNI CI/T Error Codes"
1166	   subregistry (defined in section 7.3 of [RFC8007] and located at
1167	   <https://www.iana.org/assignments/cdni-parameters>) with the
1168	   following registration:

1170	   +------------+-----------------------------------+------------------+
1171	   | Error Code | Description                       | Specification    |
1172	   +------------+-----------------------------------+------------------+
1173	   | eextension | The dCDN failed to parse a        | Section Section  |
1174	   |            | generic extension object, or does | 3.2.7 of this    |
1175	   |            | not support this extension.       | document.        |
1176	   +------------+-----------------------------------+------------------+

1178	6.3.  CDNI Media protocol types

1180	   The IANA is requested to create a new "CDNI MediaProtocol Types"
1181	   subregistry in the "Content Delivery Networks Interconnection (CDNI)
1182	   Parameters" registry.  The "CDNI Media Protocol Types" namespace
1183	   defines the valid Media Protocol object values in
1184	   Section Section 3.2.4, used by the Playlist object.  Additions to the
1185	   MediaProtocol namespace conform to the "Specification Required"
1186	   policy as defined in section 4.6 of [RFC8126], where the
1187	   specification defines the MediaProtocol Type and the protocol to
1188	   which it is associated.  The designated expert will verify that new
1189	   protocol definitions do not duplicate existing protocol definitions
1190	   and prevent gratuitous additions to the namespace.

1192	   The following table defines the initial MediaProtocol values
1193	   corresponding to the HLS, MSS, and DASH protocols:

1195	   +---------------+-------------------+---------------+---------------+
1196	   | MediaProtocol | Description       | Specification | Protocol      |
1197	   | Type          |                   |               | Specification |
1198	   +---------------+-------------------+---------------+---------------+
1199	   | hls           | HTTP Live         | RFCthis       | RFC 8216      |
1200	   |               | Streaming         |               | [RFC8216]     |
1201	   | mss           | Microsoft Smooth  | RFCthis       | MSS [MSS]     |
1202	   |               | Streaming         |               |               |
1203	   | dash          | Dynamic Adaptive  | RFCthis       | MPEG-DASH     |
1204	   |               | Streaming over    |               | [MPEG-DASH]   |
1205	   |               | HTTP (MPEG-DASH)  |               |               |
1206	   +---------------+-------------------+---------------+---------------+

1208	   [RFC Editor: Please replace RFCthis with the published RFC number for
1209	   this document.]

1211	7.  Security Considerations

1213	   All security considerations listed in section 8 of [RFC8007] and
1214	   section 7 of [RFC8008] apply to this document as well.

1216	   This document defines the capability to use regular expression within
1217	   the trigger spec for more granular content selection.  The usage of
1218	   regex introduced the risk of regex complexity attacks, a.k.a ReDos
1219	   attacks.  An attacker may be able to craft a regular expression that
1220	   can exhaust server resources and may take exponential time in in the
1221	   worst case.  An implementation MUST protect itself by at least accept
1222	   triggers only from an authenticated party over a secured connection.
1223	   An implementation SHOULD also protect itself by using secure
1224	   programing techniques and decline trigger commands that use
1225	   potentially risky regex, such techniques are readily available in
1226	   secure programming literature and are beyond the scope of this
1227	   document.

1229	8.  Acknowledgments

1231	   TBD

1233	9.  Contributors

1235	   The authors would like to thank all members of the "Streaming Video
1236	   Alliance" (SVA) Open Caching Working Group for their contribution in
1237	   support of this document.

1239	10.  References

1241	10.1.  Normative References

1243	   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
1244	              Requirement Levels", BCP 14, RFC 2119,
1245	              DOI 10.17487/RFC2119, March 1997,
1246	              <https://www.rfc-editor.org/info/rfc2119>.

1248	   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
1249	              Resource Identifier (URI): Generic Syntax", STD 66,
1250	              RFC 3986, DOI 10.17487/RFC3986, January 2005,
1251	              <https://www.rfc-editor.org/info/rfc3986>.

1253	   [RFC8006]  Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
1254	              "Content Delivery Network Interconnection (CDNI)
1255	              Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
1256	              <https://www.rfc-editor.org/info/rfc8006>.

1258	   [RFC8007]  Murray, R. and B. Niven-Jenkins, "Content Delivery Network
1259	              Interconnection (CDNI) Control Interface / Triggers",
1260	              RFC 8007, DOI 10.17487/RFC8007, December 2016,
1261	              <https://www.rfc-editor.org/info/rfc8007>.

1263	   [RFC8008]  Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
1264	              R., and K. Ma, "Content Delivery Network Interconnection
1265	              (CDNI) Request Routing: Footprint and Capabilities
1266	              Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
1267	              <https://www.rfc-editor.org/info/rfc8008>.

1269	   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
1270	              Writing an IANA Considerations Section in RFCs", BCP 26,
1271	              RFC 8126, DOI 10.17487/RFC8126, June 2017,
1272	              <https://www.rfc-editor.org/info/rfc8126>.

1274	   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
1275	              Interchange Format", STD 90, RFC 8259,
1276	              DOI 10.17487/RFC8259, December 2017,
1277	              <https://www.rfc-editor.org/info/rfc8259>.

1279	10.2.  Informative References

1281	   [MPEG-DASH]
1282	              ISO, "Information technology -- Dynamic adaptive streaming
1283	              over HTTP (DASH) -- Part 1: Media presentation description
1284	              and segment format", ISO/IEC 23009-1:2014, Edition 2, 05
1285	              2014, <http://www.iso.org/standard/65274.html>.

1287	   [MSS]      Microsoft, "[MS-SSTR]: Smooth Streaming Protocol",
1288	              Protocol Revision 8.0, September 2017,
1289	              <https://msdn.microsoft.com/en-us/library/ff469518.aspx>.

1291	   [PCRE841]  Hazel, P., "Perl Compatible Regular Expressions",
1292	              Version 8.41, July 2017, <http://www.pcre.org/>.

1294	   [RFC6707]  Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
1295	              Distribution Network Interconnection (CDNI) Problem
1296	              Statement", RFC 6707, DOI 10.17487/RFC6707, September
1297	              2012, <https://www.rfc-editor.org/info/rfc6707>.

1299	   [RFC7736]  Ma, K., "Content Delivery Network Interconnection (CDNI)
1300	              Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
1301	              December 2015, <https://www.rfc-editor.org/info/rfc7736>.

1303	   [RFC8216]  Pantos, R., Ed. and W. May, "HTTP Live Streaming",
1304	              RFC 8216, DOI 10.17487/RFC8216, August 2017,
1305	              <https://www.rfc-editor.org/info/rfc8216>.

1307	Authors' Addresses

1309	   Ori Finkelman
1310	   Qwilt
1311	   6, Ha'harash
1312	   Hod HaSharon  4524079
1313	   Israel

1315	   Phone: +972-72-2221647
1316	   Email: orif@qwilt.com

1318	   Sanjay Mishra
1319	   Verizon
1320	   13100 Columbia Pike
1321	   Silver Spring, MD  20904
1322	   USA

1324	   Email: sanjay.mishra@verizon.com