| Network Working Group | O. Finkelman |
| Internet-Draft | Qwilt |
| Updates: 8007 (if approved) | S. Mishra |
| Intended status: Standards Track | Verizon |
| Expires: March 27, 2020 | September 24, 2019 |
CDNI Control Triggers Interface Extensions
draft-ietf-cdni-triggers-extensions-03
This document updates RFC 8007 to include generic extensions and more granular content matching options, required by the Open Caching architecture. The Open Caching working group of the Streaming Video Alliance is focused on the delegation of video delivery request from commercial CDNs to a caching layer at the ISP. In that aspect, Open Caching is a specific use case of CDNI, where the commercial CDN is the upstream CDN (uCDN) and the ISP caching layer is the downstream CDN (dCDN). The extensions specified in this document to the CDNI Control Interface / Triggers are derived from requirements of Open Caching but are applicable to CDNI use cases in general.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 27, 2020.
Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
This document defines the objects and extensions required for granular content management operations. For that purpose it extends CDNI Control Interface / Triggers [RFC8007] by adding new content selection options to the trigger specification and specifying a generic extension mechanism that enables adding future functions for controlling the trigger execution. This document also defines and initial set of extension objects. This document gives examples for the extensions specified herein, for complete examples of the trigger interface usage see Section 6 of [RFC8007].
The CDNI Metadata Interface is described in [RFC8006].
The CDNI Footprint and Capability Interface is described in [RFC8008].
The CDNI Control Interface / Triggers is described in [RFC8007].
This document reuses the terminology defined in [RFC6707], [RFC8006], [RFC8007], and [RFC8008].
Additionally, the following terms are used throughout this document and are defined as follows:
The remainder of this document is organized as follows:
This document defines extensions for the CDNI Control Interface / Triggers (CI/T) [RFC8007] and defines FCI objects as per the CDNI Footprint and Capabilities Interface [RFC8008].
This document specifies version 2 of the CI/T commands and objects. In this context the CI/T commands and objects as were specified in [RFC8007] are considered to be version 1.
This document specifies version 2 of the Trigger Specification which is an enhancement of the Trigger Specification that includes all properties as defined in Section 5.2.1 of [RFC8007] as well as the additional properties required by the use cases listed below in Section 2.1.3 and Section 2.1.4.
The trigger specification as defined in Section 5.2.1 of [RFC8007] provides means to select content objects by matching a full content URL or patterns with wildcards. This document specifies two additional selection options:
The CDNI Control Interface / Triggers [RFC8007] defines a set of properties and objects used by the trigger commands. In this document we define an extension mechanism to the triggers interface that enables the application to add various functions that allow finer control over the trigger execution. This document specifies a generic trigger extension object wrapper for managing individual CDNI trigger extensions in an opaque manner.
This document also registers CDNI Payload Types [RFC7736] under the namespace CIT for the initial set of trigger extension types:
Example use cases
This document extends the CI/T Error Handling (see Section 4.7 of [RFC8007]) to support the following:
Extending the trigger mechanism with optional properties requires the ability for the dCDN to advertise which optional properties it supports.
The CDNI Footprint and Capabilities Interface [RFC8008] enables the dCDN to advertise the capabilities it supports across different footprints. This document introduces FCI objects to support the advertisement of these optional properties.
Example use cases
[RFC8007] does not define a version number and versioning scheme. We, therefore, designate the interface and objects as defined in Section 5 of [RFC8007] as version 1. The following sections define version 2 of the CI/T objects and their properties as extensions of version 1.
Version 2 of the CI/T interface requires the support of the following objects:
Usage example of version 2 of trigger command
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger-command.v2
{
"trigger.v2": { <properties of a trigger.v2 object> },
"cdn-path": [ "AS64496:0" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger-status.v2
Location: https://triggers.dcdn.example.com/triggers/0
Server: example-server/0.1
{
"errors.v2": [ { <properties of 1st error.v2 object> },
...,
{ <properties of Nth error.v2 object> }
],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"status": "pending",
"trigger.v2": { <properties of a trigger.v2 object> }
}
Usage example of version 2 of trigger status for the trigger created in the above trigger command example:
REQUEST:
GET /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 467
Expires: Wed, 04 May 2016 08:49:10 GMT
Server: example-server/0.1
ETag: "6990548174277557683"
Cache-Control: max-age=60
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Type: application/cdni; ptype=ci-trigger-status.v2
{
"errors.v2": [ { <properties of 1st error.v2 object> },
...,
{ <properties of Nth error.v2 object> }
],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"status": "pending",
"trigger.v2": { <properties of a trigger.v2 object> }
}
The CDNI CI/T interface defines a mechanism for error reporting (see Section 4.7 of [RFC8007]) and an Error Description object for reporting errors (see Section 5.2.6 of [RFC8007]). This document specifies version 2 of CI/T error handling in order to support the following:
This section defines the values that can appear in the top-level objects described in Section 3.1, and their encodings.
Version 2 of the Trigger Specification adds the following properties on top of the existing properties of the trigger specification defined in Section 5.2.1 of [RFC8007].
Example of an invalidation trigger.v2 with a list of regex objects, a list of playlist objects, and extensions:
{
"trigger.v2": {
"type": "invalidate",
"content.regexs": [ <list of RegexMatch objects> ],
"content.playlists": [ <list of Playlist objects> ],
"extensions": [ <list of GenericTriggerExtension objects ]
},
"cdn-path": [ "AS64496:0" ]
}
A RegexMatch consists of a regular expression string a URI is matched against, and flags describing the type of match. It is encoded as a JSON object with following properties:
Example of a case sensitive, no query parameters, regex match against:
"^(https:\/\/video\.example\.com)\/([a-z])\/
movie1\/([1-7])\/*(index.m3u8|\d{3}.ts)$"
{
"regex": "^(https:\\/\\/video\\.example\\.com)\\/([a-z])\\/movie1\
\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
"case-sensitive": true,
"match-query-string": false
}
This regex matches URLs of domain video.example.com where the path structure is /(single lower case letter)/(name-of-title)/(single digit between 1 to 7)/(index.m3u8 or a 3 digit number with ts extension). For example:
https://video.example.com/d/movie1/5/index.m3u8
or
https://video.example.com/k/movie1/4/013.ts
A Playlist consists of a full URL and a media protocol identifier. An implementation that supports a specific playlist media protocol MUST be able to parse playlist files of that protocol type and extract, possibly recursively, the URLs to all media objects and/or sub playlist files, and apply the trigger to each one of them separately.
Playlist is encoded as a JSON object with following properties:
Example of a HLS playlist:
{
"playlist": "https://www.example.com/hls/title/index.m3u8",
"media-protocol": "hls"
}
Media Protocol objects are used to specify registered type of media protocol (see Section 6.3) used for protocol related operations like pre-position according to playlist.
Type: JSON string
Example:
"dash"
A "trigger.v2" object, as defined in Section 3.3.1 includes an optional array of trigger extension objects. A trigger extension contain properties that are used as directives for dCDN when executing the trigger command -- for example, location policies, time policies and so on. Each such CDNI Trigger extension is a specialization of a CDNI GenericTriggerExtension object. The GenericTriggerExtension object abstracts the basic information required for trigger distribution from the specifics of any given property (i.e., property semantics, enforcement options, etc.). All trigger extensions are optional, and it is thus the responsibility of the extension specification to define a consistent default behavior for the case the extension is not present.
The trigger enforcement options concept is in accordance with the metadata enforcement options as defined in Section 3.2 of [RFC8006].
The GenericTriggerExtension object defines the properties contained within it as well as whether or not the properties are "mandatory-to-enforce". If the dCDN does not understand or support a mandatory-to-enforce property, the dCDN MUST NOT execute the trigger command. If the extension is not mandatory-to-enforce, then that GenericTriggerExtension object can be safely ignored and the trigger command can be processed in accordance with the rest of the CDNI Trigger spec.
Although a CDN MUST NOT execute a trigger command if a mandatory-to-enforce extension cannot be enforced, it could still be safe to redistribute that trigger (the "safe-to-redistribute" property) to another CDN without modification. For example, in the cascaded CDN case, a transit CDN (tCDN) could convey mandatory-to-enforce trigger extension to a dCDN. For a trigger extension that does not require customization or translation (i.e., trigger extension that is safe-to-redistribute), the data representation received off the wire MAY be stored and redistributed without being understood or supported by the tCDN. However, for trigger extension that requires translation, transparent redistribution of the uCDN trigger values might not be appropriate. Certain triggers extensions can be safely, though perhaps not optimally, redistributed unmodified. For example, pre-position command might be executed in suboptimal times for some geographies if transparently redistributed, but it might still work.
Redistribution safety MUST be specified for each GenericTriggerExtension property. If a CDN does not understand or support a given GenericTriggerExtension property that is not safe-to-redistribute, the CDN MUST set the "incomprehensible" flag to true for that GenericTriggerExtension object before redistributing it. The "incomprehensible" flag signals to a dCDN that trigger metadata was not properly transformed by the tCDN. A CDN MUST NOT attempt to execute a trigger that has been marked as "incomprehensible" by a uCDN.
tCDNs MUST NOT change the value of mandatory-to-enforce or safe-to-redistribute when propagating a trigger to a dCDN. Although a tCDN can set the value of "incomprehensible" to true, a tCDN MUST NOT change the value of "incomprehensible" from true to false.
Table 1 describes the action to be taken by a tCDN for the different combinations of mandatory-to-enforce ("MtE") and safe-to-redistribute ("StR") properties when the tCDN either does or does not understand the trigger extension object in question:
| MtE | StR | Extension object understood by tCDN | Trigger action |
|---|---|---|---|
| False | True | True | Can execute and redistribute. |
| False | True | False | Can execute and redistribute. |
| False | False | False | Can execute. MUST set "incomprehensible" to true when redistributing. |
| False | False | True | Can execute. Can redistribute after transforming the trigger extension (if the CDN knows how to do so safely); otherwise, MUST set "incomprehensible" to true when redistributing. |
| True | True | True | Can execute and redistribute. |
| True | True | False | MUST NOT execute but can redistribute.. |
| True | False | True | Can execute. Can redistribute after transforming the trigger extension (if the CDN knows how to do so safely); otherwise, MUST set "incomprehensible" to true when redistributing. |
| True | False | False | MUST NOT serve. MUST set "incomprehensible" to true when redistributing. |
Table 2 describes the action to be taken by a tCDN for the different combinations of mandatory-to-enforce and "incomprehensible" ("Incomp") properties, when the dCDN either does or does not understand the trigger extension object in question:
| MtE | Incomp | Extension object understood by dCDN | Trigger action |
|---|---|---|---|
| False | False | True | Can execute. |
| False | True | True | Can execute but MUST NOT interpret/apply any trigger extension marked as "incomprehensible". |
| False | False | False | Can execute. |
| False | True | False | Can execute but MUST NOT interpret/apply any trigger extension marked as "incomprehensible". |
| True | False | True | Can execute. |
| True | True | True | MUST NOT execute. |
| True | False | False | MUST NOT execute. |
| True | True | False | MUST NOT execute. |
A GenericTriggerExtension object is a wrapper for managing individual CDNI Trigger extensions in an opaque manner.
Example of a GenericTriggerExtension containing a specific trigger extension object:
{
"generic-trigger-extension-type":
<Type of this trigger extension object>,
"generic-trigger-extension-value":
{
<properties of this trigger extension object>
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true,
"incomprehensible": false
}
Version 2 of the Error Description adds the "content.playlists", "content.regexs", "extensions" and "cdn" properties on top of the existing properties of version 1 of the trigger Error Description as defined in Section 5.2.6 of [RFC8007].
Example of an Error Description object reporting a malformed Playlist:
{
"content.playlists": [
{
"playlist": "https://www.example.com/hls/title/index.m3u8",
"media-protocol": "hls"
}
],
"description": "Failed to parse HLS playlist",
"error": "econtent",
"cdn": "AS64500:0"
},
Example of an Error Description object reporting an unsupported extension object:
{
"errors.v2": [
{
"extensions": [
{
"generic-trigger-extension-type":
<Type of this erroneous trigger extension object>,
"generic-trigger-extension-value":
{
<properties of this erroneous trigger extension object>
},
}
],
"description": "unrecognized extension <type>",
"error": "eextension",
"cdn": "AS64500:0"
},
]
}
This document adds the error code "eextension" to the error codes table defined in Section 5.2.6 of [RFC8007]. This error code designates that an error occurred while parsing a generic trigger extension, or that the specific extension is not supported by the CDN. A CDN that fails to parse or execute a generic extension object MUST report it using the "errors.v2" array within the trigger status resource, while setting the error code to "eextension" and providing an appropriate description. The "eextension" error code is a registered type of "CDNI CI/T Trigger Error Codes" (see Section 6.2).
The following subsections provides usage examples of the specified interface extensions being used by the trigger command and status resource.
In the following example a CI/T "invalidate" command uses the Regex property to specify the range of content objects for invalidation, the command is rejected by the dCDN due to regex complexity, and an appropriate error is reflected in the status response.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger-command.v2
{
"trigger.v2": {
"type": "invalidate",
"content.regexs": [
{
"regex": "^(https:\\/\\/video\\.example\\.com)\\/
([a-z])\\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
"case-sensitive": true,
"match-query-string": false
},
{ <RegexMatch #2> },
...
{ <RegexMatch #N> },
],
},
"cdn-path": [ "AS64496:0" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger-status.v2
Location: https://triggers.dcdn.example.com/triggers/0
Server: example-server/0.1
{
"errors.v2": [
{
"content.regexs": [
{
"regex": "^(https:\\/\\/video\\.example\\.com)\\/
([a-z])\\/movie1\\/([1-7])\\/*(index.m3u8|\\d{3}.ts)$",
"case-sensitive": true,
"match-query-string": false
},
],
"description": "The dCDN rejected a regex due to complexity",
"error": "ereject",
"cdn": "AS64500:0"
},
],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"status": "failed",
"trigger.v2": { <content of trigger object from the command> }
}
In the following example a CI/T "preposition" command uses the Playlist property to specify the full media library of a specific content. The command fails due to playlist parse error and an appropriate error is reflected in the status response.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger-command.v2
{
"trigger.v2": {
"type": "preposition",
"content.playlists": [
{
"playlist": "https://www.example.com/hls/title/index.m3u8",
"media-protocol": "hls"
},
{ <Playlist #2> },
...
{ <Playlist #N> },
],
},
"cdn-path": [ "AS64496:0" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger-status.v2
Location: https://triggers.dcdn.example.com/triggers/0
Server: example-server/0.1
{
"errors.v2": [
{
"content.playlists": [
{
"playlist": "https://www.example.com/hls/title/index.m3u8",
"media-protocol": "hls"
},
],
"description": "The dCDN was not able to parse the playlist",
"error": "econtent",
"cdn": "AS64500:0"
},
],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"status": "failed",
"trigger.v2": { <content of trigger object from the command> }
}
In the following example a CI/T "preposition" command is using two extensions to control the way the trigger is executed. In this example the receiving dCDN identified as "AS64500:0" does not support the first extension in the extensions array. dCDN "AS64500:0" further distributes this trigger to another downstream CDN that is identified as "AS64501:0", which does not support the second extension in the extensions array. The error is propagate from "AS64501:0" to "AS64500:0" and the errors.v2 array reflects both errors.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: triggers.dcdn.example.com
Accept: */*
Content-Type: application/cdni; ptype=ci-trigger-command.v2
{
"trigger.v2": {
"type": "preposition",
"content.playlists": [
{
"playlist": "https://www.example.com/hls/title/index.m3u8",
"media-protocol": "hls"
},
],
"extensions": [
{
"generic-trigger-extension-type":
<Type of trigger extension object #1>,
"generic-trigger-extension-value":
{
<properties of trigger extension object #1>
},
"mandatory-to-enforce": false,
"safe-to-redistribute": true,
},
{
"generic-trigger-extension-type":
<Type of trigger extension object #2>,
"generic-trigger-extension-value":
{
<properties of trigger extension object #2>
},
"mandatory-to-enforce": false,
"safe-to-redistribute": true,
},
],
},
"cdn-path": [ "AS64496:0" ]
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 04 May 2016 08:48:10 GMT
Content-Length: 467
Content-Type: application/cdni; ptype=ci-trigger-status.v2
Location: https://triggers.dcdn.example.com/triggers/0
Server: example-server/0.1
{
"errors.v2": [
{
"extensions": [
{
"generic-trigger-extension-type":
<Type of trigger extension object #1>,
"generic-trigger-extension-value":
{
<properties of trigger extension object #1>
},
"mandatory-to-enforce": false,
"safe-to-redistribute": true,
},
],
"description": "unrecognized extension <type>",
"error": "eextension",
"cdn": "AS64500:0"
},
{
"extensions": [
{
"generic-trigger-extension-type":
<Type of trigger extension object #2>,
"generic-trigger-extension-value":
{
<properties of trigger extension object #2>
},
"mandatory-to-enforce": false,
"safe-to-redistribute": true,
},
],
"description": "unrecognized extension <type>",
"error": "eextension",
"cdn": "AS64501:0"
},
],
"ctime": 1462351690,
"etime": 1462351698,
"mtime": 1462351690,
"status": "failed",
"trigger.v2": { <content of trigger object from the command> }
}
The objects defined below are intended to be used in the GenericTriggerExtension object's generic-trigger-extension-value field as defined in Section Section 3.3.5.2, and their generic-trigger-extension-type property MUST be set to the appropriate CDNI Payload Type as defined in Section 6.1 .
A content operation may be relevant for a specific geographical region, or need to be excluded from a specific region. In this case, the trigger should be applied only to parts of the network that are either "included" or "not excluded" by the location policy. Note that the restrictions here are on the cache location rather than the client location.
The LocationPolicy object defines which CDN or cache locations for which the trigger command is relevant.
Example use cases:
Object specification
If a location policy object is not listed within the trigger command, the default behavior is to execute the trigger in all available caches and locations of the dCDN.
The trigger command is allowed, or denied, for a specific cache location according to the action of the first location whose footprint matches against that cache's location. If two or more footprints overlap, the first footprint that matches against the cache's location determines the action a CDN MUST take. If the "locations" property is an empty list or if none of the listed footprints match the location of a specific cache location, then the result is equivalent to a "deny" action.
The following is an example of generic trigger extension object containing a location policy object that allows the trigger execution in the US but blocks its execution in Canada:
{
"generic-trigger-extension-type": "CIT.LocationPolicy",
"generic-trigger-extension-value":
{
"locations": [
{
"action": "allow",
"footprints": [
{
"footprint-type": "countrycode",
"footprint-value": ["us"]
}
]
},
{
"action": "deny",
"footprints": [
{
"footprint-type": "countrycode",
"footprint-value": ["ca"]
}
]
}
]
},
"mandatory-to-enforce": true,
"safe-to-redistribute": true,
"incomprehensible": false
}
A uCDN may wish to perform content management operations on the dCDN in a specific schedule. The TimePolicy extensions allows the uCDN to instruct the dCDN to execute the trigger command in a desired time window. For example, a content provider that wishes to pre-populate a new episode at off-peak time so that it would be ready on caches at prime time when the episode is released for viewing. A scheduled operation enables the uCDN to direct the dCDN in what time frame to execute the trigger.
A uCDN may wish to to schedule a trigger such that the dCDN will execute it in local time, as it is measured in each region. For example, a uCDN may wish the dCDN to pull the content at off-peak hours, between 2AM-4AM, however, as a CDN is distributed across multiple time zones, the UTC definition of 2AM depends on the actual location.
We define two alternatives for localized scheduling:
Object specification
If a time policy object is not listed within the trigger command, the default behavior is to execute the trigger in a time frame most suitable to the dCDN taking under consideration other constrains and / or obligations.
Example of a generic trigger extension object containing a time policy object that schedules the trigger execution to a window between 09:00 01/01/2000 UTC and 17:00 01/01/2000 UTC, using the "unix-time-window" property:
{
"generic-trigger-extension-type": "CIT.TimePolicy",
"generic-trigger-extension-value":
{
"unix-time-window": {
"start": 946717200,
"end": 946746000
}
}
"mandatory-to-enforce": true,
"safe-to-redistribute": true,
"incomprehensible": false
}
A UTCWindow object describes a time range in UTC or UTC and a zone offset that can be applied by a TimePolicy.
Example UTCWindow object that describes a time window from 02:30 01/01/2000 UTC to 04:30 01/01/2000 UTC:
{
"start": 2000-01-01T02:30:00.00Z,
"end": 2000-01-01T04:30:00.00Z,
}
Example UTCWindow object that describes a time window in New York time zone offset UTC-05:00 from 02:30 01/01/2000 to 04:30 01/01/2000:
{
"start": 2000-01-01T02:30:00.00-05:00,
"end": 2000-01-01T04:30:00.00-05:00,
}
A LocalTimeWindow object describes a time range in local time. The reader of this object MUST interpret it as "the local time at the location of execution". For example, if the time window states 2AM to 4AM local time then a dCDN that has presence in both London (UTC) and New York (UTC-05:00) will execute the trigger at 2AM-4AM UTC in London and at 2AM-4AM UTC-05:00 in New York.
Example LocalTimeWindow object that describes a local time window from 02:30 01/01/2000 to 04:30 01/01/2000.
{
"start": 2000-01-01T02:30:00.00,
"end": 2000-01-01T04:30:00.00,
}
DateLocalTime is a timestamp that follows the date and local time notation in Section 4.3.2 of [ISO8601] as a complete date and time extended representation, where the time zone designator is omitted. In addition, for simplicity and as exact accuracy is not an objective in this case, this specification does not support the decimal fractions of seconds, and does not take leap second into consideration.
Type: JSON string using the format "date-local-time" as defined in Section 4.2.3.1.
The Date and Local Time format is specified here using the syntax description notation defined in [ABNF].
date-fullyear = 4DIGIT
date-month = 2DIGIT ; 01-12
date-mday = 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on
; month/year
time-hour = 2DIGIT ; 00-23
time-minute = 2DIGIT ; 00-59
time-second = 2DIGIT ; 00-59 leap seconds are not supported
local-time = time-hour ":" time-minute ":" time-second
full-date = date-fullyear "-" date-month "-" date-mday
date-local-time = full-date "T" local-time
Example time representing 09:00AM on 01/01/2000 local time:
2000-01-01T09:00:00.00
The grammar element date-mday represents the day number within the current month. The maximum value varies based on the month and year as follows:
Month Number Month/Year Maximum value of date-mday ------------ ---------- -------------------------- 01 January 31 02 February, normal 28 02 February, leap year 29 03 March 31 04 April 30 05 May 31 06 June 30 07 July 31 08 August 31 09 September 30 10 October 31 11 November 30 12 December 31
See Appendix C of [RFC3339] for a sample C code that determines if a year is a leap year.
The grammar element time-second may have the values 0-59. The value of 60 that is used in [ISO8601] to represent a leap second MUST NOT be used.
Although [ISO8601] permits the hour to be "24", this profile of [ISO8601] only allows values between "00" and "23" for the hour in order to reduce confusion.
This section covers the FCI objects required for advertisement of the extensions and properties introduced in this document.
The CI/T versions capability object is used to indicate support for one or more CI/T objects versions. Note that the default version as originally defined in [RFC8007] MUST be implicitly supported regardless of the versions listed in this capability object.
The following shows an example of CI/T Versions Capability object serialization for a dCDN that supports versions 2 and 2.1 of the CI/T interface.
{
"capabilities": [
{
"capability-type": "FCI.TriggerVersion",
"capability-value": {
"versions": [ "1", "2", "2.1" ]
},
"footprints": [
<Footprint objects>
]
}
]
}
The CI/T Playlist Protocol capability object is used to indicate support for one or more MediaProtocol types listed in Section 6.3 by the playlists property of the "trigger.v2" object.
The following shows an example of CI/T Playlist Protocol Capability object serialization for a dCDN that supports "hls" and "dash".
{
"capabilities": [
{
"capability-type": "FCI.TriggerPlaylistProtocol",
"capability-value": {
"media-protocols": ["hls", "dash"]
},
"footprints": [
<Footprint objects>
]
}
]
}
The CI/T Generic Extension capability object is used to indicate support for one or more GenericExtensionObject types.
The following shows an example of CI/T Trigger Extension Capability object serialization for a dCDN that supports the "CIT.LocationPolicy" and the "CIT.TimePolicy" objects.
{
"capabilities": [
{
"capability-type": "FCI.TriggerGenericExtension",
"capability-value": {
"trigger-extension": ["CIT.LocationPolicy", "CIT.TimePolicy"]
},
"footprints": [
<Footprint objects>
]
}
]
}
This document requests the registration of the following CDNI Payload Types under the IANA "CDNI Payload Types" registry defined in [RFC7736]:
| Payload Type | Specification |
|---|---|
| ci-trigger-command.v2 | RFCthis |
| ci-trigger-status.v2 | RFCthis |
| CIT.LocationPolicy | RFCthis |
| CIT.TimePolicy | RFCthis |
| FCI.TriggerVersion | RFCthis |
| FCI.TriggerPlaylistProtocol | RFCthis |
| FCI.TriggerGenericExtension | RFCthis |
[RFC Editor: Please replace RFCthis with the published RFC number for this document.]
Purpose: The purpose of this payload type is to distinguish version 2 of the CI/T command (and any associated capability advertisement)
Interface: CI/T
Encoding: see Section 3.1
Purpose: The purpose of this payload type is to distinguish version 2 of the CI/T status resource response (and any associated capability advertisement)
Interface: CI/T
Encoding: see Section 3.1
Purpose: The purpose of this Trigger Extension type is to distinguish LocationPolicy CIT Trigger Extension objects.
Interface: CI/T
Encoding: see Section 4.1
Purpose: The purpose of this Trigger Extension type is to distinguish TimePolicy CI/T Trigger Extension objects.
Interface: CI/T
Encoding: see Section 4.2
Purpose: The purpose of this payload type is to distinguish FCI advertisement objects for CI/T Triggers Versions objects
Interface: FCI
Encoding: see Section 5.1.1
Purpose: The purpose of this payload type is to distinguish FCI advertisement objects for CI/T Playlist Protocol objects
Interface: FCI
Encoding: see Section 5.2.1
Purpose: The purpose of this payload type is to distinguish FCI advertisement objects for CI/T Extension objects
Interface: FCI
Encoding: see Section 5.3.1
The IANA is requested to update the "CDNI CI/T Error Codes" subregistry (defined in Section 7.3 of [RFC8007] and located at <https://www.iana.org/assignments/cdni-parameters>) with the following registration:
| Error Code | Description | Specification |
|---|---|---|
| eextension | The dCDN failed to parse a generic extension object, or does not support this extension. | Section Section 3.3.7 of this document. |
The IANA is requested to create a new "CDNI MediaProtocol Types" subregistry in the "Content Delivery Networks Interconnection (CDNI) Parameters" registry. The "CDNI MediaProtocol Types" namespace defines the valid MediaProtocol object values in Section Section 3.3.4, used by the Playlist object. Additions to the MediaProtocol namespace conform to the "Specification Required" policy as defined in Section 4.6 of [RFC8126], where the specification defines the MediaProtocol Type and the protocol to which it is associated. The designated expert will verify that new protocol definitions do not duplicate existing protocol definitions and prevent gratuitous additions to the namespace.
The following table defines the initial MediaProtocol values corresponding to the HLS, MSS, and DASH protocols:
| MediaProtocol Type | Description | Specification | Protocol Specification |
|---|---|---|---|
| hls | HTTP Live Streaming | RFCthis | RFC 8216 |
| mss | Microsoft Smooth Streaming | RFCthis | MSS |
| dash | Dynamic Adaptive Streaming over HTTP (MPEG-DASH) | RFCthis | MPEG-DASH |
[RFC Editor: Please replace RFCthis with the published RFC number for this document.]
All security considerations listed in Section 8 of [RFC8007] and Section 7 of [RFC8008] apply to this document as well.
This document defines the capability to use regular expression within the trigger spec for more granular content selection. The usage of regex introduced the risk of regex complexity attacks, a.k.a ReDos attacks. An attacker may be able to craft a regular expression that can exhaust server resources and may take exponential time in the worst case. An implementation MUST protect itself by at least accept triggers only from an authenticated party over a secured connection. An implementation SHOULD also protect itself by using secure programing techniques and decline trigger commands that use potentially risky regex, such techniques are readily available in secure programming literature and are beyond the scope of this document.
TBD
The authors would like to thank all members of the "Streaming Video Alliance" (SVA) Open Caching Working Group for their contribution in support of this document.
| [ISO8601] | ISO, "Data elements and interchange formats -- Information interchange -- Representation of dates and times", ISO 8601:2004, Edition 3, December 2004. |
| [MPEG-DASH] | ISO, "Information technology -- Dynamic adaptive streaming over HTTP (DASH) -- Part 1: Media presentation description and segment format", ISO/IEC 23009-1:2014, Edition 2, May 2014. |
| [MSS] | Microsoft, "[MS-SSTR]: Smooth Streaming Protocol", Protocol Revision 8.0, September 2017. |
| [PCRE841] | Hazel, P., "Perl Compatible Regular Expressions", Version 8.41, July 2017. |
| [RFC6707] | Niven-Jenkins, B., Le Faucheur, F. and N. Bitar, "Content Distribution Network Interconnection (CDNI) Problem Statement", RFC 6707, DOI 10.17487/RFC6707, September 2012. |
| [RFC7736] | Ma, K., "Content Delivery Network Interconnection (CDNI) Media Type Registration", RFC 7736, DOI 10.17487/RFC7736, December 2015. |
| [RFC8216] | Pantos, R. and W. May, "HTTP Live Streaming", RFC 8216, DOI 10.17487/RFC8216, August 2017. |