--- 1/draft-ietf-cdni-control-triggers-04.txt 2014-12-29 04:15:36.763689049 -0800 +++ 2/draft-ietf-cdni-control-triggers-05.txt 2014-12-29 04:15:36.835690817 -0800 @@ -1,18 +1,18 @@ Network Working Group R. Murray Internet-Draft B. Niven-Jenkins Intended status: Standards Track Velocix (Alcatel-Lucent) -Expires: March 7, 2015 September 3, 2014 +Expires: July 2, 2015 December 29, 2014 CDNI Control Interface / Triggers - draft-ietf-cdni-control-triggers-04 + draft-ietf-cdni-control-triggers-05 Abstract This document describes the part of the CDN Interconnection Control Interface that allows a CDN to trigger activity in an interconnected CDN that is configured to deliver content on its behalf. The upstream CDN can use this mechanism to request that the downstream CDN pre-positions metadata or content, or that it invalidates or purges metadata or content. The upstream CDN can monitor the status of activity that it has triggered in the downstream CDN. @@ -31,21 +31,21 @@ 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 http://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 7, 2015. + This Internet-Draft will expire on July 2, 2015. Copyright Notice Copyright (c) 2014 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -54,70 +54,71 @@ 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 2. Model for CDNI Triggers . . . . . . . . . . . . . . . . . . . 4 2.1. Timing of Triggered Activity . . . . . . . . . . . . . . 6 - 2.2. Trigger Results . . . . . . . . . . . . . . . . . . . . . 6 - 3. Collections of Trigger Status Resources . . . . . . . . . . . 6 - 4. CDNI Trigger Interface . . . . . . . . . . . . . . . . . . . 7 - 4.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 8 + 2.2. Scope of Triggered Activity . . . . . . . . . . . . . . . 6 + 2.3. Trigger Results . . . . . . . . . . . . . . . . . . . . . 6 + 3. Collections of Trigger Status Resources . . . . . . . . . . . 7 + 4. CDNI Trigger Interface . . . . . . . . . . . . . . . . . . . 8 + 4.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 9 4.2. Checking Status . . . . . . . . . . . . . . . . . . . . . 10 4.2.1. Polling Trigger Status Resource collections . . . . . 10 - 4.2.2. Polling Trigger Status Resources . . . . . . . . . . 10 - 4.3. Cancelling Triggers . . . . . . . . . . . . . . . . . . . 10 - 4.4. Deleting Triggers . . . . . . . . . . . . . . . . . . . . 11 + 4.2.2. Polling Trigger Status Resources . . . . . . . . . . 11 + 4.3. Cancelling Triggers . . . . . . . . . . . . . . . . . . . 11 + 4.4. Deleting Triggers . . . . . . . . . . . . . . . . . . . . 12 4.5. Expiry of Trigger Status Resources . . . . . . . . . . . 12 - 4.6. Loop Detection and Prevention . . . . . . . . . . . . . . 12 + 4.6. Loop Detection and Prevention . . . . . . . . . . . . . . 13 4.7. Error Handling . . . . . . . . . . . . . . . . . . . . . 13 - 4.8. Content URLs . . . . . . . . . . . . . . . . . . . . . . 13 - 5. CI/T Object Properties and Encoding . . . . . . . . . . . . . 14 - 5.1. CI/T Objects . . . . . . . . . . . . . . . . . . . . . . 14 - 5.1.1. CI/T Commands . . . . . . . . . . . . . . . . . . . . 14 - 5.1.2. Trigger Status Resource . . . . . . . . . . . . . . . 15 - 5.1.3. Trigger Collection . . . . . . . . . . . . . . . . . 16 - 5.2. Properties of CI/T Objects . . . . . . . . . . . . . . . 17 + 4.8. Content URLs . . . . . . . . . . . . . . . . . . . . . . 14 + 5. CI/T Object Properties and Encoding . . . . . . . . . . . . . 15 + 5.1. CI/T Objects . . . . . . . . . . . . . . . . . . . . . . 15 + 5.1.1. CI/T Commands . . . . . . . . . . . . . . . . . . . . 15 + 5.1.2. Trigger Status Resource . . . . . . . . . . . . . . . 16 + 5.1.3. Trigger Collection . . . . . . . . . . . . . . . . . 17 + 5.2. Properties of CI/T Objects . . . . . . . . . . . . . . . 18 5.2.1. Trigger Specification . . . . . . . . . . . . . . . . 18 - 5.2.2. Trigger Type . . . . . . . . . . . . . . . . . . . . 19 - 5.2.3. Trigger Status . . . . . . . . . . . . . . . . . . . 19 - 5.2.4. PatternMatch . . . . . . . . . . . . . . . . . . . . 20 - 5.2.5. Absolute Time . . . . . . . . . . . . . . . . . . . . 21 - 5.2.6. Error Description . . . . . . . . . . . . . . . . . . 21 - 5.2.7. Error Code . . . . . . . . . . . . . . . . . . . . . 22 - 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 22 - 6.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 23 - 6.1.1. Preposition . . . . . . . . . . . . . . . . . . . . . 23 - 6.1.2. Invalidate . . . . . . . . . . . . . . . . . . . . . 24 - 6.2. Examining Trigger Status . . . . . . . . . . . . . . . . 25 - 6.2.1. Collection of All Triggers . . . . . . . . . . . . . 25 - 6.2.2. Filtered Collections of Triggers . . . . . . . . . . 26 - 6.2.3. Trigger Status Resources . . . . . . . . . . . . . . 28 - 6.2.4. Polling for Change . . . . . . . . . . . . . . . . . 30 - 6.2.5. Removing a Trigger . . . . . . . . . . . . . . . . . 33 + 5.2.2. Trigger Type . . . . . . . . . . . . . . . . . . . . 20 + 5.2.3. Trigger Status . . . . . . . . . . . . . . . . . . . 20 + 5.2.4. PatternMatch . . . . . . . . . . . . . . . . . . . . 21 + 5.2.5. Absolute Time . . . . . . . . . . . . . . . . . . . . 22 + 5.2.6. Error Description . . . . . . . . . . . . . . . . . . 22 + 5.2.7. Error Code . . . . . . . . . . . . . . . . . . . . . 23 + 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 23 + 6.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 24 + 6.1.1. Preposition . . . . . . . . . . . . . . . . . . . . . 24 + 6.1.2. Invalidate . . . . . . . . . . . . . . . . . . . . . 25 + 6.2. Examining Trigger Status . . . . . . . . . . . . . . . . 26 + 6.2.1. Collection of All Triggers . . . . . . . . . . . . . 26 + 6.2.2. Filtered Collections of Trigger Status Resources . . 27 + 6.2.3. Individual Trigger Status Resources . . . . . . . . . 29 + 6.2.4. Polling for Change . . . . . . . . . . . . . . . . . 31 + 6.2.5. Deleting Trigger Status Resources . . . . . . . . . . 34 6.2.6. Error Reporting . . . . . . . . . . . . . . . . . . . 35 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36 - 7.1. Media type registrations . . . . . . . . . . . . . . . . 36 - 7.1.1. CI/T Commands . . . . . . . . . . . . . . . . . . . . 36 - 7.1.2. CI/T Trigger Status Resource . . . . . . . . . . . . 37 - 7.1.3. CI/T Trigger Collection . . . . . . . . . . . . . . . 38 - 8. Security Considerations . . . . . . . . . . . . . . . . . . . 39 - 8.1. Authentication, Confidentiality, Integrity Protection . . 39 - 8.2. Denial of Service . . . . . . . . . . . . . . . . . . . . 39 - 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 40 - 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 40 - 10.1. Normative References . . . . . . . . . . . . . . . . . . 40 - 10.2. Informative References . . . . . . . . . . . . . . . . . 40 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41 + 7.1. Media type registrations . . . . . . . . . . . . . . . . 37 + 7.1.1. CI/T Commands . . . . . . . . . . . . . . . . . . . . 37 + 7.1.2. CI/T Trigger Status Resource . . . . . . . . . . . . 38 + 7.1.3. CI/T Trigger Collection . . . . . . . . . . . . . . . 39 + 8. Security Considerations . . . . . . . . . . . . . . . . . . . 40 + 8.1. Authentication, Confidentiality, Integrity Protection . . 40 + 8.2. Denial of Service . . . . . . . . . . . . . . . . . . . . 40 + 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 41 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 41 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 41 + 10.2. Informative References . . . . . . . . . . . . . . . . . 41 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42 1. Introduction [RFC6707] introduces the problem scope for CDN Interconnection (CDNI) and lists the four categories of interfaces that may be used to compose a CDNI solution (Control, Metadata, Request Routing, Logging). [RFC7336] expands on the information provided in [RFC6707] and describes each of the interfaces and the relationships between them @@ -140,64 +141,63 @@ o Section 5 lists properties of CI/T Commands and Status Resources. o Section 6 contains example messages. 1.1. Terminology This document reuses the terminology defined in [RFC6707]. 2. Model for CDNI Triggers - A trigger, sent from the uCDN to the dCDN, is a request for the dCDN - to do some work relating to data originating from the uCDN. + A CI/T Command, sent from the uCDN to the dCDN, is a request for the + dCDN to do some work relating to data associated with content + requests originating from the uCDN. - The trigger can request action on either metadata or content, the - following actions can be requested: + There are two types of CI/T Command, CI/T Trigger Commands and CI/T + Cancel Commands. The CI/T Cancel Command can be used to request + cancellation of an earlier CI/T Trigger Command. A CI/T Trigger + Command is of one of the following types: o preposition - used to instruct the dCDN to fetch metadata from the uCDN, or content from any origin including the uCDN. o invalidate - used to instruct the dCDN to revalidate specific metadata or content before re-using it. o purge - used to instruct the dCDN to delete specific metadata or content. - Multiple representations of an HTTP resource may share the same URL. - Requests to invalidate and purge metadata or content apply to all - resource representations with matching URLs. - The CI/T interface is a web service offered by the dCDN. It allows - creation and deletion of triggers, and tracking of the triggered - activity. When the dCDN accepts a trigger it creates a resource - describing status of the triggered activity, a Trigger Status - Resource. The uCDN can poll Trigger Status Resources to monitor - progress. + CI/T commands to be issued, and triggered activity to be tracked. + When the dCDN accepts a CI/T Command it creates a resource describing + status of the triggered activity, a Trigger Status Resource. The + uCDN can poll Trigger Status Resources to monitor progress. - The dCDN maintains a collection of Trigger Status Resources for each - uCDN, each uCDN only has access to its own collection and the - location of that collection is shared when CDN interconnection is - established. + The dCDN maintains at least one collection of Trigger Status + Resources for each uCDN. Each uCDN only has access to its own + collections, the locations of which are shared when CDN + interconnection is established. To trigger activity in the dCDN, the uCDN POSTs a CI/T Command to the - collection of Trigger Status Resources. If the dCDN accepts the - trigger, it creates a new Trigger Status Resource and returns its + collection of Trigger Status Resources. If the dCDN accepts the CI/T + Command, it creates a new Trigger Status Resource and returns its location to the uCDN. To monitor progress, the uCDN can GET the - Trigger Status Resource. To request cancellation of a trigger the - uCDN can POST to the collection of Trigger Status Resources, or - simply DELETE the Trigger Status Resource. + Trigger Status Resource. To request cancellation of a CI/T Trigger + Command the uCDN can POST to the collection of Trigger Status + Resources, or simply DELETE the Trigger Status Resource. In addition to the collection of all Trigger Status Resources for the uCDN, the dCDN can maintain filtered views of that collection. These filtered views are defined in Section 3 and include collections of - active and completed triggers. These collections provide a mechanism - for polling the status of multiple jobs. + Trigger Status Resources corresponding to active and completed CI/T + Trigger Commands. These collections provide a mechanism for polling + the status of multiple jobs. Figure 1 is an example showing the basic message flow used by the uCDN to trigger activity in the dCDN, and for the uCDN to discover the status of that activity. Only successful triggering is shown. Examples of the messages are given in Section 6. uCDN dCDN | (1) POST http://dcdn.example.com/triggers/uCDN | [ ] --------------------------------------------------> [ ]--+ | [ ] | (2) @@ -217,432 +217,468 @@ | | | | Figure 1: Basic CDNI Message Flow for Triggers The steps in Figure 1 are: 1. The uCDN triggers action in the dCDN by posting a CI/T Command to a collection of Trigger Status Resources, "http://dcdn.example.com/triggers/uCDN". The URL of this was - given to the uCDN when the trigger interface was established. + given to the uCDN when the CI/T interface was established. - 2. The dCDN authenticates the request, validates the trigger and if - it accepts the request, creates a new Trigger Status Resource. + 2. The dCDN authenticates the request, validates the CI/T Command + and, if it accepts the request, creates a new Trigger Status + Resource. 3. The dCDN responds to the uCDN with an HTTP 201 response status, and the location of the Trigger Status Resource. - 4. The uCDN can repeatedly poll the Trigger Status Resource in the - dCDN. + 4. The uCDN can poll, possibly repeatedly, the Trigger Status + Resource in the dCDN. 5. The dCDN responds with the Trigger Status Resource, describing - progress or results of the triggered activity. + progress or results of the CI/T Trigger Command. The remainder of this document describes the messages, Trigger Status Resources, and collections of Trigger Status Resources in more detail. 2.1. Timing of Triggered Activity - Timing of the execution of triggered activity is under the dCDN's - control, including its start-time and pacing of the activity in the - network. + Timing of the execution of CI/T Commands is under the dCDN's control, + including its start-time and pacing of the activity in the network. - Invalidate and purge triggers MUST be applied to all data acquired - before the trigger was created in the dCDN. The dCDN MAY apply the - triggers to data acquired after trigger creation. + CI/T invalidate and purge commands MUST be applied to all data + acquired before the command was accepted by the dCDN. The dCDN + SHOULD NOT apply CI/T invalidate and purge commands to data acquired + after the CI/T Command was accepted, but this may not always be + achievable so the uCDN cannot count on that. - If the uCDN wishes to invalidate or purge content, then immediately + If the uCDN wishes to invalidate or purge content then immediately pre-position replacement content at the same URLs, it SHOULD ensure the dCDN has completed the invalidate/purge before initiating the prepositioning. Otherwise, there is a risk that the dCDN pre- positions the new content, then immediately invalidates or purges it (as a result of the two uCDN requests running in parallel). -2.2. Trigger Results + Because the CI/T Command timing is under the dCDN's control, the dCDN + implementation can choose whether to apply CI/T invalidate and purge + commands to content acquisition that has already started when the + command is received. - Each trigger can operate on multiple metadata and content URLs. The - trigger MUST NOT be reported as "complete" until all actions have - been completed successfully. The reasons for failure, and URLs or - Patterns affected, SHOULD be enumerated in the Trigger Status - Resource. For more detail, see section Section 4.7. +2.2. Scope of Triggered Activity - If a dCDN is also acting as a uCDN in a cascade, it MUST forward - triggers to any downstream CDNs that may have data affected by the - trigger. The trigger MUST NOT be reported as 'complete' in a CDN - until it is 'complete' in all of its downstream CDNs. If a trigger - is reported as 'processed' in any dCDN, intermediate CDNs MUST NOT - report 'complete', instead they must also report 'processed'. A - trigger MAY be reported as 'failed' as soon as it fails in a CDN or - in any of its downstream CDNs. A cancelled trigger MUST be reported - as 'cancelling' until it has been reported as 'cancelled', - 'complete', or 'failed' by all dCDNs in a cascade. + Each CI/T Command can operate on multiple metadata and content URLs. + + Multiple representations of an HTTP resource may share the same URL. + CI/T Trigger Commands that invalidate or purge metadata or content + apply to all resource representations with matching URLs. + + The dCDN MUST reject CI/T Commands from a uCDN that act on another + uCDN's data. Security considerations are discussed further in + section Section 8. + +2.3. Trigger Results + + Possible states for a Trigger Status Resource are defined in section + Section 5.2.3. + + The CI/T Trigger Command MUST NOT be reported as 'complete' until all + actions have been completed successfully. The reasons for failure, + and URLs or Patterns affected, SHOULD be enumerated in the Trigger + Status Resource. For more detail, see section Section 4.7. + + If a dCDN is also acting as a uCDN in a cascade, it MUST forward CI/T + Commands to any downstream CDNs that may be affected. The CI/T + Trigger Command MUST NOT be reported as 'complete' in a CDN until it + is 'complete' in all of its downstream CDNs. If a CI/T Trigger + Command is reported as 'processed' in any dCDN, intermediate CDNs + MUST NOT report 'complete', instead they must also report + 'processed'. A CI/T Command MAY be reported as 'failed' as soon as + it fails in a CDN or in any of its downstream CDNs. A cancelled CI/T + Trigger Command MUST be reported as 'cancelling' until it has been + reported as 'cancelled', 'complete', or 'failed' by all dCDNs in a + cascade. 3. Collections of Trigger Status Resources As described in Section 2, Trigger Status Resources exist in the dCDN to report the status of activity triggered by each uCDN. A collection of Trigger Status Resources is a resource that contains a reference to each Trigger Status Resource in that collection. The dCDN MUST make a collection of a uCDN's Trigger Status Resources - available to that uCDN. This collection includes all of the uCDN - triggers that have been accepted by the dCDN, and have not yet been - deleted by the uCDN, or expired and removed by the dCDN (as described - in section Section 4.4). Trigger Status Resources belonging to a - uCDN MUST NOT be visible to any other CDN. The dCDN could, for - example, achieve this by offering different collection URLs to each - uCDN, or by filtering the response based on the client uCDN. + available to that uCDN. This collection includes all of the Trigger + Status Resources created for CI/T Commands from the uCDN that have + been accepted by the dCDN, and have not yet been deleted by the uCDN, + or expired and removed by the dCDN (as described in section + Section 4.4). Trigger Status Resources belonging to a uCDN MUST NOT + be visible to any other CDN. The dCDN could, for example, achieve + this by offering different collection URLs to each uCDN, and/or by + filtering the response based on the uCDN with which the HTTP client + is associated. To trigger activity in a dCDN, or to cancel triggered activity, the uCDN POSTs a CI/T Command to the dCDN's collection of the uCDN's Trigger Status Resources. In order to allow the uCDN to check the status of multiple jobs in a single request, the dCDN SHOULD also maintain collections representing filtered views of the collection of all Trigger Status - Resources. If it implements these filtered collections, the dCDN - MUST include links to them in the collection of all triggers. The - filtered collections are: + Resources. These filtered collections are optional-to-implement but, + if implemented, the dCDN MUST include links to them in the collection + of all Trigger Status Resources. The filtered collections are: - o Pending - Trigger Status Resources for triggers that have been - accepted, but not yet acted upon. + o Pending - Trigger Status Resources for CI/T Trigger Commands that + have been accepted, but not yet acted upon. - o Active - Trigger Status Resources for triggered activity that is - currently being processed in the dCDN. + o Active - Trigger Status Resources for CI/T Trigger Commands that + are currently being processed in the dCDN. o Complete - Trigger Status Resources representing activity that - completed successfully and 'processed' triggers for which no - further status updates will be made by the dCDN. + completed successfully, and 'processed' CI/T Trigger Commands for + which no further status updates will be made by the dCDN. - o Failed - Trigger Status Resources representing activity that - failed or was cancelled by the uCDN. + o Failed - Trigger Status Resources representing CI/T Commands that + failes or were cancelled by the uCDN. 4. CDNI Trigger Interface This section describes an interface to enable an upstream CDN to trigger activity in a downstream CDN. - Requests are made over HTTP, and the HTTP Method defines the - operation the request would like to perform. The corresponding HTTP - Response returns the status of the operation in the HTTP Status Code - and returns the current representation of the resource (if - appropriate) in the Response Body. HTTP Responses from dCDNs - implementing CI/T that contain a response body SHOULD include an ETag - to enable validation of cached versions of returned resources. + The CI/T interface builds on top of HTTP, so dCDNs may make use of + any HTTP feature when implementing the CI/T interface. For example, + a dCDN SHOULD make use of HTTP's caching mechanisms to indicate that + a requested response/representation has not been modified, reducing + the uCDN's processing needed to determine whether the status of + triggered activity has changed. All dCDNs implementing CI/T MUST support the HTTP GET, HEAD, POST and - DELETE methods as defined in [RFC7231]. The only representation - specified in this document is JSON, [RFC7159]. + DELETE methods as defined in [RFC7231]. + + The only representation specified in this document is JSON, + [RFC7159]. It MUST be supported by the uCDN and by the dCDN. The URL of the dCDN's collection of all Trigger Status Resources needs to be either discovered by, or configured in, the uCDN. The mechanism for discovery of that URL is outside the scope of this document. CI/T Commands are POSTed to the dCDN's collection of all Trigger - Status Resources. If a command to create a new trigger is accepted - by the dCDN, it creates a new Trigger Status Resource and returns its - URI to the dCDN in an HTTP 201 response. The triggered activity can - then be monitored by the uCDN using that resource and the collections + Status Resources. If a CI/T Trigger Command is accepted by the dCDN, + the dCDN creates a new Trigger Status Resource and returns its URI to + the uCDN in an HTTP 201 response. The triggered activity can then be + monitored by the uCDN using that resource and the collections described in Section 3. The URI of each Trigger Status Resource is returned to the uCDN when - it is created. This means all Trigger Status Resources can be - discovered, so dCDNs are free to assign whatever structure they - desire to the URIs for CI/T resources. Therefore uCDNs MUST NOT make - any assumptions regarding the structure of CI/T URIs or the mapping - between CI/T objects and their associated URIs. URIs present in the - examples in this document are purely illustrative and are not - intended to impose a definitive structure on CI/T interface - implementations. - - The CI/T interface builds on top of HTTP, so dCDNs may make use of - any HTTP feature when implementing the CI/T interface. For example, - a dCDN SHOULD make use of HTTP's caching mechanisms to indicate that - a requested response/representation has not been modified, reducing - the uCDN's processing needed to determine whether the status of - triggered activity has changed. - - The dCDN MUST ensure that activity triggered by the uCDN only affects - metadata or content originating from that uCDN. + it is created, and URIs of all Trigger Status Resources are listed in + the dCDN's collection of all Trigger Status Resources. This means + all Trigger Status Resources can be discovered by the uCDN, so dCDNs + are free to assign whatever structure they desire to the URIs for CI/ + T resources. Therefore uCDNs MUST NOT make any assumptions regarding + the structure of CI/T URIs or the mapping between CI/T objects and + their associated URIs. URIs present in the examples in this document + are purely illustrative and are not intended to impose a definitive + structure on CI/T interface implementations. 4.1. Creating Triggers - To create a new trigger, the uCDN makes an HTTP POST to the dCDN's + To issue a CI/T Command, the uCDN makes an HTTP POST to the dCDN's collection of all of the uCDN's Trigger Status Resources. The - request body of that POST is a CI/T Command with a "trigger", as - described in Section 5.1.1. + request body of that POST is a CI/T Command, as described in + Section 5.1.1. - The dCDN validates and authenticates that request, if it is malformed - or the uCDN does not have sufficient access rights it MUST either - respond with an appropriate 4xx HTTP error code and a resource MUST - NOT be created on the dCDN, or create a 'failed' Trigger Status - Resource containing an appropriate error description. + The dCDN validates and authenticates that CI/T Command, if it is + malformed or the uCDN does not have sufficient access rights it MUST + either respond with an appropriate 4xx HTTP error code and a Trigger + Status Resource MUST NOT be created on the dCDN, or create a 'failed' + Trigger Status Resource containing an appropriate error description. - If the request is accepted, the uCDN MUST create a new Trigger Status - Resource. The HTTP response to the dCDN MUST have status code 201 - and the URI of the Trigger Status Resource in the Location header - field. The HTTP response SHOULD include the content of the newly - created Trigger Status Resource, this is recommended particularly in - cases where the trigger has completed immediately. + When a CI/T Trigger Command is accepted, the uCDN MUST create a new + Trigger Status Resource which will convey a specification of the CI/T + Command and its current status. The HTTP response to the dCDN MUST + have status code 201 and MUST convey the URI of the Trigger Status + Resource in the Location header field. The HTTP response SHOULD + include the content of the newly created Trigger Status Resource, + this is recommended particularly in cases where the CI/T Trigger + Command has completed immediately. Once a Trigger Status Resource has been created the dCDN MUST NOT re- - use its location, even after that resource has been removed. - - The "trigger" property of the Trigger Status Resource contains the - Trigger Specification posted in the body of the CI/T Command. Note - that this need not be a byte-for-byte copy. For example, in the JSON - representation the dCDN may re-serialise the information differently. + use its URI, even after that Trigger Status Resource has been + removed. - If the dCDN is not able to track the execution of triggered activity, - it MUST indicate that it has accepted the request but will not be - providing further status updates. To do this, it sets the "status" - of the Trigger Status Resource to "processed". In this case, CI/T - processing should continue as for a "complete" request, so the - Trigger Status Resource MUST be added to the dCDN's collection of - Complete Triggers. The dCDN SHOULD also provide an estimated - completion time for the request, by using the "etime" property of the - Trigger Status Resource. This will allow the uCDN to schedule - prepositioning after an earlier delete of the same URLs is expected - to have finished. + The dCDN SHOULD track and report on progress of CI/T Trigger + Commands. If the dCDN is not able to do that, it MUST indicate that + it has accepted the request but will not be providing further status + updates. To do this, it sets the "status" of the Trigger Status + Resource to "processed". In this case, CI/T processing should + continue as for a "complete" request, so the Trigger Status Resource + MUST be added to the dCDN's collection of Complete Trigger Status + Resources. The dCDN SHOULD also provide an estimated completion time + for the request, by using the "etime" property of the Trigger Status + Resource. This will allow the uCDN to schedule prepositioning after + an earlier delete of the same URLs is expected to have finished. - If the dCDN is able to track the execution of triggered activity, the - trigger is queued by the dCDN for later action, the "status" property - of the Trigger Status Resource MUST be "pending". Once trigger + If the dCDN is able to track the execution of CI/T Commands and a CI/ + T Command is queued by the dCDN for later action, the "status" + property of the Trigger Status Resource MUST be "pending". Once processing has started the "status" MUST be "active". Finally, once - the triggered activity is complete, the trigger status MUST be set to - "complete" or "failed". + the CI/T Command is complete, the status MUST be set to "complete" or + "failed". - A trigger may result in no activity in the dCDN if, for example, it - is an invalidate or purge request for data the dCDN has not yet - acquired, or a prepopulate request for data it has already acquired - and which is still valid. In this case, the "status" of the Trigger - Status Resource MUST be "processed" or "complete", and the Trigger - Status Resource MUST be added to the dCDN's collection of Complete - Triggers. + A CI/T Trigger Command may result in no activity in the dCDN if, for + example, it is an invalidate or purge request for data the dCDN has + not yet acquired, or a prepopulate request for data it has already + acquired and which is still valid. In this case, the "status" of the + Trigger Status Resource MUST be "processed" or "complete", and the + Trigger Status Resource MUST be added to the dCDN's collection of + Complete Trigger Status Resources. Once created, Trigger Status Resources can be cancelled or deleted by the uCDN, but not modified. The dCDN MUST reject PUT and POST requests from the uCDN to Trigger Status Resources by responding with an appropriate HTTP status code. 4.2. Checking Status - The uCDN has two ways to check progress of activity it has triggered - in the dCDN, described in sections Section 4.2.1 and Section 4.2.2. + The uCDN has two ways to check progress of CI/T Commands it has + issued to the dCDN, described in sections Section 4.2.1 and + Section 4.2.2. - To check for change in status of a resource or collection of - resources without re-fetching the whole resource or collection, - Entity Tags SHOULD be included by the dCDN for the uCDN to use as - cache validators, as defined in [RFC7232]. + To check for change in status of a Trigger Status Resource or + collection of Trigger Status Resources without re-fetching the whole + Resource or Collection, Entity Tags SHOULD be included by the dCDN + for the uCDN to use as cache validators, as defined in [RFC7232]. The dCDN SHOULD use the cache control headers for responses to GETs for Trigger Status Resources and Collections to indicate the frequency at which it recommends the uCDN should poll for change. 4.2.1. Polling Trigger Status Resource collections The uCDN can fetch the collection of its Trigger Status Resources, or filtered views of that collection. - This makes it possible to poll status of all triggered activity in a - single request. If the dCDN moves a Trigger Status Resource from the - Active to the Completed collection, the uCDN can fetch the result of - that activity. + This makes it possible to poll status of all CI/T Trigger Commands in + a single request. If the dCDN moves a Trigger Status Resource from + the Active to the Completed collection, the uCDN can fetch the result + of that activity. When polling in this way, the uCDN SHOULD use HTTP Entity Tags to monitor for change, rather than repeatedly fetching the whole collection. 4.2.2. Polling Trigger Status Resources The uCDN has a URI provided by the dCDN for each Trigger Status - Resource it has created, it may fetch that resource at any time. + Resource it has created, it may fetch that Trigger Status Resource at + any time. This can be used to retrieve progress information, and to fetch the - result of triggered activity. + result of the CI/T Command. When polling in this way, the uCDN SHOULD use HTTP Entity Tags to monitor for change, rather than repeatedly fetching the Trigger Status Resource. 4.3. Cancelling Triggers - The uCDN can request cancellation of a trigger by POSTing a Trigger - "cancel" Command to the collection of all triggers. + The uCDN can request cancellation of a CI/T Trigger Command by + POSTing a CI/T Cancel Command to the collection of all Trigger Status + Resources. - The uCDN should respond to that command appropriately, for example - with HTTP status code 200 "OK" if the cancellation has been processed - and the trigger is inactive, 202 "Accepted" if the command has been - accepted but the trigger remains active, or 403 "Forbidden" if - cancellation is not supported by the dCDN. + Cancellation of a CI/T Trigger Command is optional-to-implement in + the dCDN. + + The dCDN MUST respond to the CI/T Cancel Command appropriately, for + example with HTTP status code 200 "OK" if the cancellation has been + processed and the CI/T Command is inactive, 202 "Accepted" if the + command has been accepted but the CI/T Command remains active, or 403 + "Forbidden" if cancellation is not supported by the dCDN. If cancellation of a "pending" Trigger Status Resource is accepted by the dCDN, the dCDN SHOULD NOT start processing of that activity. - Cancelling a "pending" trigger does not however guarantee that not - activity is started, because the uCDN cannot control the timing of - that activity. Processing could, for example, start after the POST - is sent by the uCDN but before that request is processed by the dCDN. + Issuing a CT/T cancel command for a "pending" Trigger Status Resource + does not however guarantee that the corresponding activity will not + be started, because the uCDN cannot control the timing of that + activity. Processing could, for example, start after the POST is + sent by the uCDN but before that request is processed by the dCDN. If cancellation of an "active" or "processed" Trigger Status Resource - is accepted by the dCDN, the dCDN SHOULD stop processing the - triggered activity. However, as with cancellation of a "pending" - trigger, the dCDN does not guarantee this. + is accepted by the dCDN, the dCDN SHOULD stop processing the CI/T + Command. However, as with cancellation of a "pending" CI/T Command, + the dCDN does not guarantee this. - If the triggered activity cannot be stopped immediately, the - trigger's status MUST be set to "cancelling" and the Trigger Status - Resource remains in the collection of active triggers. If processing - is stopped before normal completion, the trigger's status MUST be set - to "cancelled" and included in the collection of failed triggers. + If the CI/T Command cannot be stopped immediately, the status in the + corresponding Trigger Status Resource MUST be set to "cancelling", + and the Trigger Status Resource MUST remain in the collection of + Trigger Status Resources for active CI/T Commands. If processing is + stopped before normal completion, the status value in the Trigger + Status Resource MUST be set to "cancelled", and the Trigger Status + Resource MUST be included in the collection of failed CT/T Trigger + Commands. Cancellation of a "complete" or "failed" Trigger Status Resource requires no processing in the dCDN, its status MUST NOT be changed to "cancelled". 4.4. Deleting Triggers The uCDN can delete Trigger Status Resources at any time, using the HTTP DELETE method. The effect is similar to cancellation, but no Trigger Status Resource remains afterwards. Once deleted, the references to a Trigger Status Resource MUST be removed from all Trigger Status Resource collections. Subsequent - requests to GET the deleted resource SHOULD fail. + requests to GET the deleted Trigger Status Resource SHOULD be + rejected by the dCDN with an HTTP error. If a "pending" Trigger Status Resource is deleted, the dCDN SHOULD - NOT start processing of that activity. Deleting a "pending" trigger - does not however guarantee that it has not started because the uCDN - cannot control the timing of that activity. Processing may, for - example, start after the DELETE is sent by the uCDN but before that - request is processed by the dCDN. + NOT start processing of that activity. Deleting a "pending" Trigger + Status Resource does not however guarantee that it has not started + because the uCDN cannot control the timing of that activity. + Processing may, for example, start after the DELETE is sent by the + uCDN but before that request is processed by the dCDN. If an "active" or "processed" Trigger Status Resource is deleted, the - dCDN MAY stop processing the triggered activity. However, as with - deletion of a "pending" trigger, the dCDN does not guarantee this. + dCDN SHOULD stop processing the CI/T Command. However, as with + deletion of a "pending" Trigger Status Resource, the dCDN does not + guarantee this. Deletion of a "complete" or "failed" Trigger Status Resource requires - no processing in the dCDN other than deletion of the resource. + no processing in the dCDN other than deletion of the Trigger Status + Resource. 4.5. Expiry of Trigger Status Resources The dCDN can choose to automatically delete Trigger Status Resources some time after they become "complete", "processed", "failed" or - "cancelled". In this case, the dCDN will remove the resource and - respond to subsequent requests for it with an HTTP error. + "cancelled". In this case, the dCDN will remove the Trigger Status + Resource and respond to subsequent requests for it with an HTTP + error. If the dCDN performs this housekeeping, it MUST have reported the length of time after which completed Trigger Status Resources will be deleted via a property of the collection of all Trigger Status - Resources. It is recommended that Trigger Status Resources are not - automatically deleted for at least 24 hours after they become - "complete", "processed", "failed" or "cancelled". + Resources. It is RECOMMENDED that Trigger Status Resources are not + automatically deleted by the dCDN for at least 24 hours after they + become "complete", "processed", "failed" or "cancelled". - To ensure it is able to get the status of its completed and failed - triggers, it is recommended that the uCDN's polling interval is less - than the time after which records for completed activity will be - deleted. + To ensure it is able to get the status of its Trigger Status + Resources for completed and failed CI/T Commands, it is RECOMMENDED + that the uCDN polling interval is less than the time after which + records for completed activity will be deleted. 4.6. Loop Detection and Prevention Given three CDNs, A, B and C. If CDNs B and C delegate delivery of - CDN A's content to each other, CDN A's triggers could be passed + CDN A's content to each other, CDN A's CI/T Commands could be passed between CDNs B and C in a loop. More complex networks of CDNs could contain similar loops involving more hops. In order to prevent and detect such CI/T loops, each CDN uses a CDN Provider ID to uniquely identify itself. Each CDN MUST insert its CDN Provider ID into the cdn-path key of every CI/T Command it - originates or cascades. When receiving CI/T commands a dCDN MUST + originates or cascades. When receiving CI/T Commands a dCDN MUST check the cdn-path and reject any CI/T Command which already contains its own CDN Provider ID in the cdn-path. Transit CDNs MUST check the cdn-path and not cascade the CI/T Command to dCDNs that are already listed in cdn-path. - The CDN Provider Id consists of the characters AS followed by the CDN - Provider's AS number, then a colon (':') and an additional qualifier - that is used to guarantee uniqueness in case a particular AS has - multiple independent CDNs deployed. For example "AS64496:0". + The CDN Provider Id consists of the two characters "AS" followed by + the CDN Provider's Autonomous System number, then a colon (':') and + an additional qualifier that is used to guarantee uniqueness in case + a particular AS has multiple independent CDNs deployed. For example + "AS64496:0". + + If the CDN provider has multiple Autonomous Systems, the same AS + number SHOULD be used in all messages from that CDN provider, unless + there are multiple distinct CDNs. If the RI interface described in [I-D.ietf-cdni-redirection] is implemented by the dCDN, the CI/T and RI interfaces SHOULD use the same CDN Provider Id. 4.7. Error Handling - A dCDN can reject a CI/T Command using HTTP status codes. For - example, 400 if the request is malformed, or 401 if the uCDN does not - have permission to create triggers or it is trying to act on another - CDN's data. + A dCDN can signal rejection of a CI/T Command using HTTP status + codes. For example, 400 if the request is malformed, or 401 if the + uCDN does not have permission to issue CI/T Commands or it is trying + to act on another CDN's data. - If any part of the trigger fails, the trigger SHOULD be reported as - "failed" once its activity is complete or if no further errors will - be reported. The "errors" property in the Trigger Status Resource - will be used to enumerate which actions failed and the reasons for - failure, and can be present while the trigger is still "pending" or - "active", if the trigger is still running for some URLs or Patterns - in the Trigger Specification. + If any part of the CI/T Trigger Command fails, the trigger SHOULD be + reported as "failed" once its activity is complete or if no further + errors will be reported. The "errors" property in the Trigger Status + Resource will be used to enumerate which actions failed and the + reasons for failure, and can be present while the Trigger Status + Resource is still "pending" or "active", if the CI/T Trigger Command + is still running for some URLs or Patterns in the Trigger + Specification. Once a request has been accepted, processing errors are reported in the Trigger Status Resource using a list of Error Descriptions. Each Error Description is used to report errors against one or more of the URLs or Patterns in the Trigger Specification. - If a surrogate affected by a trigger is offline in the dCDN, or the - dCDN is unable to pass a CI/T Command on to any of its cascaded - dCDNs: + If a surrogate affected by a CI/T Trigger Command is offline in the + dCDN, or the dCDN is unable to pass a CI/T Command on to any of its + cascaded dCDNs: - o If the request is abandoned by the dCDN, the dCDN SHOULD report an - error. + o If the CI/T Command is abandoned by the dCDN, the dCDN SHOULD + report an error. - o An "invalidate" trigger may be reported as "complete" when + o A CI/T "invalidate" command may be reported as "complete" when surrogates that may have the data are offline. In this case, surrogates MUST NOT use the affected data without first revalidating it when they are back online. - o "preposition" and "purge" triggers can be reported as "processed" - if affected caches are offline and the activity will complete when - they return to service. + o CI/T "preposition" and "purge" commands can be reported as + "processed" if affected caches are offline and the activity will + complete when they return to service. - o Otherwise, the dCDN SHOULD keep the trigger in state "pending" or - "active" until the trigger is acted upon, or the uCDN chooses to - cancel it. + o Otherwise, the dCDN SHOULD keep the Trigger Status Resource in + state "pending" or "active" until the CI/T Command is acted upon, + or the uCDN chooses to cancel it. 4.8. Content URLs To refer to content in the dCDN, the uCDN MUST present URLs in the same form as in the metadata it supplied to the dCDN. By definition, it is always possible for the dCDN to locate content based on URLs in this form. Therefore, if content URLs are transformed by an intermediate CDN in - a cascade, that intermediate CDN MUST transform URLs in CI/T commands + a cascade, that intermediate CDN MUST transform URLs in CI/T Commands it passes to its dCDN. When processing Trigger Specifications, CDNs MUST ignore the URL - scheme (http or https) in comparing URLs. For example, for an - invalidate or purge trigger, content MUST be invalidated or purged + scheme (http or https) in comparing URLs. For example, for a CI/T + invalidate or purge command, content MUST be invalidated or purged regardless of the protocol clients use to request it. 5. CI/T Object Properties and Encoding CI/T Commands, Trigger Status Resources and Trigger Collections and their properties are encoded using JSON, as defined in sections Section 5.1.1, Section 5.2.1, and Section 5.1.2. - Names in JSON are case sensitive and therefore the names and literal - values specified here MUST always use lower-case. + Names in JSON are case sensitive. The names and literal values + specified in the present document MUST always use lower-case. Unrecognised name/value pairs in JSON objects SHOULD NOT be treated - as an error by either the uCDN or dCDN. + as an error by either the uCDN or dCDN. They SHOULD be ignored in + the processing, and passed on by dCDN to any further dCDNs in a + cascade. 5.1. CI/T Objects The top-level objects defined by the CI/T interface are described in this section. Each has an associated MIME Media Type. The encoding of values used by these objects is described in Section 5.2. 5.1.1. CI/T Commands CI/T Commands SHOULD use a MIME Media Type of application/ @@ -655,22 +691,23 @@ Description: A specification of the trigger type, and a set of data to act upon. Value: A Trigger Specification, as defined in Section 5.2.1. Mandatory: No, but exactly one of "trigger" or "cancel" MUST be present in a CI/T Command. Name: cancel - Description: The URLs of Trigger Status Resources for triggers - that the uCDN wants to cancel. + + Description: The URLs of Trigger Status Resources for CI/T + Trigger Commands that the uCDN wants to cancel. Value: A JSON array of URLs represented as JSON strings. Mandatory: No, but exactly one of "trigger" or "cancel" MUST be present in a CI/T Command. Name: cdn-path Description: The CDN Provider Identifiers of CDNs that have already accepted the CI/T Command. @@ -683,22 +720,24 @@ 5.1.2. Trigger Status Resource Trigger Status Resources SHOULD use a MIME Media Type of application/ cdni.ci.TriggerStatus+json. A Trigger Status Resource is encoded as a JSON object containing the following name/value pairs. Name: trigger - Description: The Trigger Specification that was used to create - this Trigger Status Resource. + Description: The Trigger Specification posted in the body of + the CI/T Command. Note that this need not be a byte-for-byte + copy. For example, in the JSON representation the dCDN may re- + serialise the information differently. Value: A Trigger Specification, as defined in Section 5.2.1. Mandatory: Yes Name: ctime Description: Time at which the CI/T Command was received by the dCDN. Time is determined by the dCDN, there is no requirement to synchronise clocks between interconnected CDNs. @@ -747,99 +787,104 @@ 5.1.3. Trigger Collection Trigger Collections SHOULD use a MIME Media Type of application/ cdni.ci.TriggerCollection+json. A Trigger Collection is encoded as a JSON object containing the following name/value pairs. Name: triggers + Description: Links to Trigger Status Resources in the collection. Value: A JSON array of URLs represented as JSON strings. Mandatory: Yes Name: staleresourcetime - Description: The length of time for which the dCDN guarantees to keep a completed Trigger Status Resource. After this time, - the dCDN SHOULD delete the resource and all references to it - from collections. + the dCDN SHOULD delete the Trigger Status Resource and all + references to it from collections. Value: A JSON number, integer time in seconds. Mandatory: Yes, in the collection of all Trigger Status Resources if the dCDN deletes stale entries. If the property is present in the filtered collections, it MUST have the same value as in the collection of all Trigger Status Resources. Names: coll-all, coll-pending, coll-active, coll-complete, coll- failed Description: Link to a Trigger Collection. Value: A URL represented as a JSON string. - Mandatory: Links to filtered collections are mandatory in the - collection of all Trigger Status Resources, if the dCDN - implements the filtered collections. Otherwise, optional. + Mandatory: Links to all of the filtered collections are + mandatory in the collection of all Trigger Status Resources, if + the dCDN implements the filtered collections. Otherwise, + optional. Name: cdn-id Description: The CDN Provider Identifier of the dCDN. Value: A JSON string, the dCDN's CDN Provider Identifier, as defined in Section 4.6. Mandatory: Only in the collection of all Trigger Status Resources, if the dCDN implements the filtered collections. - Optional in the filtered collections. + Optional in the filtered collections (the uCDN can always find + the dCDN's cdn-id in the collection of all Trigger Status + Resources, but the dCDN can choose to repeat that information + in its implementation of filtered collections). 5.2. Properties of CI/T Objects This section defines the values that can appear in the top level objects described in Section 5.1, and their encodings. 5.2.1. Trigger Specification A Trigger Collection is encoded as a JSON object containing the following name/value pairs. An unrecognised name/value pair in the Trigger Specification object contained in a CI/T Command SHOULD be preserved in the Trigger Specification of any Trigger Status Resource it creates. Name: type - Description: This property defines the type of the trigger. + Description: This property defines the type of the CI/T Trigger + Command. Value: Trigger Type, as defined in Section 5.2.2. Mandatory: Yes Name: metadata.urls - Description: The uCDN URLs of the metadata the trigger applies - to. + Description: The uCDN URLs of the metadata the CI/T Trigger + Command applies to. Value: A JSON array of URLs represented as JSON strings. Mandatory: No, but at least one of 'metadata.*' or 'content.*' MUST be present and non-empty. Name: content.urls - Description: URLs of content the trigger applies to, see - Section 4.8. + Description: URLs of content the CI/T Trigger Command applies + to, see Section 4.8. Value: A JSON array of URLs represented as JSON strings. Mandatory: No, but at least one of 'metadata.*' or 'content.*' MUST be present and non-empty. Name: content.ccid Description: The Content Collection Identifier of content the trigger applies to. The 'ccid' is a grouping of content, as @@ -884,42 +929,47 @@ | preposition | A request for the dCDN to acquire metadata or | | | content. | | invalidate | A request for the dCDN to invalidate metadata or | | | content. After servicing this request the dCDN will | | | not use the specified data without first re- | | | validating it using, for example, an "If-None- | | | Match" HTTP request. The dCDN need not erase the | | | associated data. | | purge | A request for the dCDN to erase metadata or | | | content. After servicing the request, the specified | - | | data MUST NOT be held on the dCDN. | + | | data MUST NOT be held on the dCDN (the dCDN should | + | | re-acquire the metadata or content from uCDN if it | + | | needs it). | +-------------+-----------------------------------------------------+ 5.2.3. Trigger Status This describes the current status of a Trigger. It MUST be one of the JSON strings in the following table: +------------+------------------------------------------------------+ | JSON | Description | | String | | +------------+------------------------------------------------------+ - | pending | The trigger has not yet been acted upon. | - | active | The trigger is currently being acted upon. | - | complete | The triggered activity completed successfully. | - | processed | The trigger has been accepted and no further status | - | | update will be made (can be used in cases where | - | | completion cannot be confirmed). | - | failed | The triggered activity could not be completed. | - | cancelling | The triggered activity is still in progress, but the | - | | trigger has been cancelled by the uCDN. | - | cancelled | The triggered activity was cancelled by the uCDN. | + | pending | The CI/T Trigger Command has not yet been acted | + | | upon. | + | active | The CI/T Trigger Command is currently being acted | + | | upon. | + | complete | The CI/T Trigger Command completed successfully. | + | processed | The CI/T Trigger Command has been accepted and no | + | | further status update will be made (can be used in | + | | cases where completion cannot be confirmed). | + | failed | The CI/T Trigger Command could not be completed. | + | cancelling | Processing of the CI/T Trigger Command is still in | + | | progress, but the CI/T Trigger Command has been | + | | cancelled by the uCDN. | + | cancelled | The CI/T Trigger Command was cancelled by the uCDN. | +------------+------------------------------------------------------+ 5.2.4. PatternMatch A Pattern Match consists of a string pattern to match, and flags describing the type of match. It is encoded as a JSON object with the following name/value pairs: Name: pattern @@ -960,22 +1009,22 @@ "pattern": "http://www.example.com/trailers/*", "case-sensitive": true } 5.2.5. Absolute Time A JSON number, seconds since the UNIX epoch. 5.2.6. Error Description - An Error Description is used to report failure of a Trigger Command, - or in the activity it triggered. + An Error Description is used to report failure of a CI/T Command, or + in the activity it triggered. Name: error Value: Error Code, as defined in Section 5.2.7. Mandatory: Yes. Names: metadata.urls, content.urls, metadata.patterns, content.patterns @@ -1007,56 +1056,56 @@ 5.2.7. Error Code This type is used by the dCDN to report failures in trigger processing. +------------+------------------------------------------------------+ | Error Code | Description | +------------+------------------------------------------------------+ | emeta | The dCDN was unable to acquire metadata required to | | | fulfil the request. | - | econtent | The dCDN was unable to acquire content (preposition | - | | triggers only). | - | eperm | The uCDN does not have permission to trigger the | - | | requested activity (for example, the data is owned | - | | by another CDN). | - | ereject | The dCDN is not willing to fulfil the request (for | - | | example, a preposition request for content at a time | - | | when the dCDN would not accept Request Routing | + | econtent | The dCDN was unable to acquire content (CT/T | + | | preposition commands only). | + | eperm | The uCDN does not have permission to issue the CI/T | + | | Command (for example, the data is owned by another | + | | CDN). | + | ereject | The dCDN is not willing to fulfil the CI/T Command | + | | (for example, a preposition request for content at a | + | | time when the dCDN would not accept Request Routing | | | requests from the uCDN). | | ecdn | An internal error in the dCDN or one of its | | | downstream CDNs. | | ecancelled | The uCDN cancelled the request. | +------------+------------------------------------------------------+ 6. Examples The following sections provide examples of different CI/T objects encoded as JSON. Discovery of the triggers interface is out of scope of this document. In an implementation, all CI/T URLs are under the control of the dCDN. The uCDN MUST NOT attempt to ascribe any meaning to individual elements of the path. In examples in this section, the URL 'http://dcdn.example.com/ - triggers' is used as the location of the collection of all triggers, - and the CDN Provider Id of uCDN is "AS64496:1". + triggers' is used as the location of the collection of all Trigger + Status Resources, and the CDN Provider Id of uCDN is "AS64496:1". 6.1. Creating Triggers Examples of the uCDN triggering activity in the dCDN: 6.1.1. Preposition - An example of a preposition request, a POST to the "AllTriggers" - collection. + An example of a CI/T preposition command, a POST to the collection of + all Trigger Status Resources. Note that "metadata.patterns" and "content.patterns" are not allowed in a preposition Trigger Specification. REQUEST: POST /triggers HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* @@ -1101,26 +1150,27 @@ ], "metadata.urls": [ "http://metadata.example.com/a/b/c" ], "type": "preposition" } } 6.1.2. Invalidate - An example of an invalidate request, another POST to the - "AllTriggers" collection. This instructs the dCDN to re-validate the - content at "http://www.example.com/a/index.html", as well as any - metadata and content whose URLs are prefixed by - "http://metadata.example.com/a/b/" and "http://www.example.com/a/b/" - respectively, using case-insensitive matching. + An example of a CI/T invalidate command, another POST to the + collection of all Trigger Status Resources. This instructs the dCDN + to re-validate the content at "http://www.example.com/a/index.html", + as well as any metadata and content whose URLs are prefixed by + "http://metadata.example.com/a/b/" using case-insensitive matching, + and "http://www.example.com/a/b/" respectively, using case-sensitive + matching. REQUEST: POST /triggers HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* Content-Type: application/cdni.ci.TriggerCommand+json Content-Length: 384 @@ -1130,22 +1180,22 @@ "metadata.patterns" : [ { "pattern" : "http://metadata.example.com/a/b/*" } ], "content.urls" : [ "http://www.example.com/a/index.html" ], "content.patterns" : [ { "pattern" : "http://www.example.com/a/b/*", "case-sensitive" : true } - ] + ] }, "cdn-path" : [ "AS64496:1" ] } RESPONSE: HTTP/1.1 201 Created Date: Sun, 31 Aug 2014 09:53:19 GMT Content-Length: 551 Content-Type: application/cdni.ci.TriggerStatus+json @@ -1171,29 +1221,30 @@ { "pattern": "http://metadata.example.com/a/b/*" } ], "type": "invalidate" } } 6.2. Examining Trigger Status - Once triggers have been created, the uCDN can check their status as - shown in these examples. + Once Trigger Status Resources have been created, the uCDN can check + their status as shown in these examples. 6.2.1. Collection of All Triggers - The uCDN can fetch the set of all the triggers it has created and - which have not yet been deleted or removed as expired. After - creation of the "preposition" and "invalidate" triggers shown above, - this collection might look as follows: + The uCDN can fetch the collection of all Trigger Status Resources it + has created that have not yet been deleted or removed as expired. + + After creation of the "preposition" and "invalidate" triggers shown + above, this collection might look as follows: REQUEST: GET /triggers HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* RESPONSE: @@ -1212,25 +1263,25 @@ "coll-complete": "/triggers/complete", "coll-failed": "/triggers/failed", "coll-pending": "/triggers/pending", "staleresourcetime": 86400, "triggers": [ "http://dcdn.example.com/triggers/0", "http://dcdn.example.com/triggers/1" ] } -6.2.2. Filtered Collections of Triggers +6.2.2. Filtered Collections of Trigger Status Resources The filtered collections are also available to the uCDN. Before the - dCDN starts processing the two triggers shown above, both will appear - in the collection of Pending Triggers, for example: + dCDN starts processing the two CI/T Trigger Commands shown above, + both will appear in the collection of Pending Triggers, for example: REQUEST: GET /triggers/pending HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* RESPONSE: @@ -1244,22 +1295,22 @@ Content-Type: application/cdni.ci.TriggerCollection+json { "staleresourcetime": 86400, "triggers": [ "http://dcdn.example.com/triggers/0", "http://dcdn.example.com/triggers/1" ] } - At this point, if no other triggers had been created, the other - filtered views of the triggers would be empty. For example: + At this point, if no other Trigger Status Resources had been created, + the other filtered views would be empty. For example: REQUEST: GET /triggers/complete HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* RESPONSE: @@ -1270,25 +1321,25 @@ Etag: "2986340333785000363" Cache-Control: max-age=60 Date: Sun, 31 Aug 2014 09:53:19 GMT Content-Type: application/cdni.ci.TriggerCollection+json { "staleresourcetime": 86400, "triggers": [] } -6.2.3. Trigger Status Resources +6.2.3. Individual Trigger Status Resources The Trigger Status Resources can also be examined for detail about - individual triggers. For example, for the "preposition" and - "invalidate" triggers from previous examples: + individual CI/T Trigger Commands. For example, for the CI/T + "preposition" and "invalidate" commands from previous examples: REQUEST: GET /triggers/0 HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* RESPONSE: @@ -1357,22 +1408,23 @@ { "pattern": "http://metadata.example.com/a/b/*" } ], "type": "invalidate" } } 6.2.4. Polling for Change - The uCDN SHOULD use the Entity Tags of collections or resources when - polling for change in status, as shown in the following examples: + The uCDN SHOULD use the Entity Tags of collections or Trigger Status + Resources when polling for change in status, as shown in the + following examples: REQUEST: GET /triggers/pending HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* If-None-Match: "5012053611544832286" RESPONSE: @@ -1398,24 +1450,25 @@ HTTP/1.1 304 Not Modified Content-Length: 0 Expires: Sun, 31 Aug 2014 09:54:19 GMT Server: example-server/0.1 Etag: "-4765587034697674779" Cache-Control: max-age=60 Date: Sun, 31 Aug 2014 09:53:19 GMT Content-Type: application/cdni.ci.TriggerStatus+json - When the triggered activity is complete, the contents of the filtered - collections will be updated, along with their Entity Tags. For - example, when the two example triggers are complete, the collections - of pending and complete triggers might look like: + When the CI/T Trigger Command is complete, the contents of the + filtered collections will be updated along with their Entity Tags. + For example, when the two example CI/T Trigger Commands are complete, + the collections of pending and complete Trigger Status Resources + might look like: REQUEST: GET /triggers/pending HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* RESPONSE: @@ -1452,44 +1505,43 @@ Content-Type: application/cdni.ci.TriggerCollection+json { "staleresourcetime": 86400, "triggers": [ "http://dcdn.example.com/triggers/0", "http://dcdn.example.com/triggers/1" ] } -6.2.5. Removing a Trigger +6.2.5. Deleting Trigger Status Resources - To request the dCDN to cancel a Trigger, the uCDN can delete the - Trigger Resource. It can also delete completed and failed triggers - to reduce the size of the collections. For example, to remove the + The dCDN can delete completed and failed Trigger Status Resources to + reduce the size of the collections. For example, to delete the "preposition" request from earlier examples: REQUEST: DELETE /triggers/0 HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* RESPONSE: HTTP/1.1 204 No Content Date: Sun, 31 Aug 2014 09:53:30 GMT Content-Length: 0 Content-Type: text/html; charset=UTF-8 Server: example-server/0.1 - This would, for example, cause the collection of completed triggers - shown in the example above to be updated to: + This would, for example, cause the collection of completed Trigger + Status Resources shown in the example above to be updated to: REQUEST: GET /triggers/complete HTTP/1.1 User-Agent: example-user-agent/0.1 Host: dcdn.example.com Accept: */* RESPONSE: @@ -1698,43 +1749,45 @@ Author: Rob Murray Change controller: IESG Note: No "charset" parameter is defined for this registration because a charset parameter is not defined for application/json [RFC7159]. 8. Security Considerations 8.1. Authentication, Confidentiality, Integrity Protection - A CI/T dCDN server implementation MUST support TLS transport for HTTP - (https) as per [RFC2818]. The use of TLS for transport of the CI/T - interface allows the dCDN and the uCDN to authenticate each other (to - ensure they are receiving CI/T Commands from, or reporting status to, - an authenticated CDN). + A CI/T implementation MUST support TLS transport for HTTP (https) as + per [RFC2818]. The use of TLS for transport of the CI/T interface + allows the dCDN and the uCDN to authenticate each other (to ensure + they are receiving CI/T Commands from, or reporting status to, an + authenticated CDN). In an environment where any such protection is required, TLS SHOULD be used for transport of the CI/T requests and responses, unless alternate methods are used for ensuring that only authorised clients are able to access their own data (such as setting up an IPsec tunnel between the two CDNs, or using a physically secured internal network between two CDNs that are owned by the same corporate entity). Both parties of the transaction (the uCDN and the dCDN) SHOULD use mutual authentication. A TLS implementation of CI/T MUST support the TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 cipher suite ([RFC5288]). An implementation of the CI/T Interface SHOULD prefer cipher suites which support perfect forward secrecy over cipher suites that don't. HTTP requests that attempt to access or operate on CI/T data belonging to another CDN MUST be rejected using, for example, HTTP - "403 Forbidden" or "404 Not Found". + "403 Forbidden" or "404 Not Found". This is intended to prevent + unauthorised users from generating unnecessary load in dCDN or uCDN + due to revalidation, reacquisition, or unnecessary acquisition. Note that in a "diamond" configuration, where one uCDN's content can be acquired via more than one directly-connected uCDN, it may not be possible for the dCDN to determine from which uCDN it acquired content. In this case, the dCDN MUST allow each uCDN from which the content could have been acquired to act upon that content using CI/T Commands. 8.2. Denial of Service @@ -1771,28 +1824,29 @@ [RFC7231] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content", RFC 7231, June 2014. [RFC7232] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests", RFC 7232, June 2014. 10.2. Informative References [I-D.ietf-cdni-metadata] - Niven-Jenkins, B., Murray, R., Caulfield, M., Leung, K., - and K. Ma, "CDN Interconnection Metadata", draft-ietf- - cdni-metadata-07 (work in progress), July 2014. + Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma, + "CDN Interconnection Metadata", draft-ietf-cdni- + metadata-08 (work in progress), October 2014. [I-D.ietf-cdni-redirection] Niven-Jenkins, B. and R. Brandenburg, "Request Routing Redirection Interface for CDN Interconnection", draft- - ietf-cdni-redirection-03 (work in progress), August 2014. + ietf-cdni-redirection-06 (work in progress), December + 2014. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois Counter Mode (GCM) Cipher Suites for TLS", RFC 5288, August 2008. [RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content Distribution Network Interconnection (CDNI) Problem Statement", RFC 6707, September 2012. @@ -1806,19 +1860,19 @@ 2014. Authors' Addresses Rob Murray Velocix (Alcatel-Lucent) 3 Ely Road Milton, Cambridge CB24 6DD UK - Email: rmurray@velocix.com + Email: rob.murray@alcatel-lucent.com Ben Niven-Jenkins Velocix (Alcatel-Lucent) 3 Ely Road Milton, Cambridge CB24 6DD UK - Email: ben@velocix.com + Email: ben.niven-jenkins@alcatel-lucent.com