CDNI Control Interface / Triggers
draft-ietf-cdni-control-triggers-03
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 8007.
|
|
|---|---|---|---|
| Authors | Rob Murray , Ben Niven-Jenkins | ||
| Last updated | 2014-07-03 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 8007 (Proposed Standard) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-cdni-control-triggers-03
Network Working Group R. Murray
Internet-Draft B. Niven-Jenkins
Intended status: Standards Track Velocix (Alcatel-Lucent)
Expires: January 3, 2015 July 2, 2014
CDNI Control Interface / Triggers
draft-ietf-cdni-control-triggers-03
Abstract
This document describes the part of the CDN Interconnect 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 re-validate or
purge metadata or content. The upstream CDN can monitor the status
of activity that it has triggered in the downstream CDN.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
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 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 January 3, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
carefully, as they describe your rights and restrictions with respect
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Model for CDNI Triggers . . . . . . . . . . . . . . . . . . . 5
2.1. Timing of Triggered Activity . . . . . . . . . . . . . . 7
2.2. Trigger Results . . . . . . . . . . . . . . . . . . . . . 7
3. Collections of Trigger Status Resources . . . . . . . . . . . 7
4. CDNI Trigger interface . . . . . . . . . . . . . . . . . . . 8
4.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 9
4.2. Checking Status . . . . . . . . . . . . . . . . . . . . . 11
4.2.1. Polling Trigger Status Resource collections . . . . . 11
4.2.2. Polling Trigger Status Resources . . . . . . . . . . 11
4.3. Deleting Triggers . . . . . . . . . . . . . . . . . . . . 11
4.4. Expiry of Trigger Status Resources . . . . . . . . . . . 12
4.5. Error Handling . . . . . . . . . . . . . . . . . . . . . 12
5. Properties of Triggers . . . . . . . . . . . . . . . . . . . 13
5.1. Properties of Trigger Requests . . . . . . . . . . . . . 13
5.1.1. Content URLs . . . . . . . . . . . . . . . . . . . . 14
5.2. Properties of Trigger Status Resources . . . . . . . . . 15
5.3. Properties of ErrorDesc . . . . . . . . . . . . . . . . . 16
5.4. Properties of Trigger Collections . . . . . . . . . . . . 17
5.5. Trigger Resource Simple Data Type Descriptions . . . . . 17
5.5.1. TriggerType . . . . . . . . . . . . . . . . . . . . . 17
5.5.2. TriggerStatus . . . . . . . . . . . . . . . . . . . . 18
5.5.3. URLs . . . . . . . . . . . . . . . . . . . . . . . . 18
5.5.4. AbsoluteTime . . . . . . . . . . . . . . . . . . . . 18
5.5.5. ErrorCode . . . . . . . . . . . . . . . . . . . . . . 18
6. JSON Encoding of Objects . . . . . . . . . . . . . . . . . . 19
6.1. JSON Encoding of Embedded Types . . . . . . . . . . . . . 20
6.1.1. TriggerType . . . . . . . . . . . . . . . . . . . . . 20
6.1.2. TriggerStatus . . . . . . . . . . . . . . . . . . . . 20
6.1.3. PatternMatch . . . . . . . . . . . . . . . . . . . . 20
6.1.4. ErrorDesc . . . . . . . . . . . . . . . . . . . . . . 21
6.1.5. ErrorCode . . . . . . . . . . . . . . . . . . . . . . 22
6.2. MIME Media Types . . . . . . . . . . . . . . . . . . . . 22
7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.1. Creating Triggers . . . . . . . . . . . . . . . . . . . . 23
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7.1.1. Preposition . . . . . . . . . . . . . . . . . . . . . 23
7.1.2. Invalidate . . . . . . . . . . . . . . . . . . . . . 24
7.2. Examining Trigger Status . . . . . . . . . . . . . . . . 25
7.2.1. Collection of All Triggers . . . . . . . . . . . . . 25
7.2.2. Filtered Collections of Triggers . . . . . . . . . . 26
7.2.3. Trigger Status Resources . . . . . . . . . . . . . . 28
7.2.4. Polling for Change . . . . . . . . . . . . . . . . . 30
7.2.5. Cancelling or Removing a Trigger . . . . . . . . . . 33
7.2.6. Error Reporting . . . . . . . . . . . . . . . . . . . 35
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
8.1. CI/T MIME Media Types . . . . . . . . . . . . . . . . . . 36
9. Security Considerations . . . . . . . . . . . . . . . . . . . 36
9.1. Authentication, Confidentiality, Integrity Protection . . 36
9.2. Denial of Service . . . . . . . . . . . . . . . . . . . . 37
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 37
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 37
11.1. Normative References . . . . . . . . . . . . . . . . . . 37
11.2. Informative References . . . . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38
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).
[I-D.ietf-cdni-framework] expands on the information provided in
[RFC6707] and describes each of the interfaces and the relationships
between them in more detail.
This document describes the "CI/T" interface, "CDNI Control interface
/ Triggers". It does not consider those parts of the control
interface that relate to configuration, bootstrapping or
authentication of CDN Interconnect interfaces. Requirements for CI/T
are the "High" and "Medium" priority requirements for the CI
identified in section 4 of [I-D.ietf-cdni-requirements], reproduced
here for convenience:
CI-1 [HIGH] The CDNI Control interface shall allow the Upstream
CDN to request that the Downstream CDN, including downstream
cascaded CDNs, delete an object or set of objects and/or its CDNI
metadata from the CDN surrogates and any storage. Only the
object(s) and CDNI metadata that pertain to the requesting
Upstream CDN are allowed to be purged.
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CI-2 [MED] The CDNI Control interface should allow for multiple
content items identified by a Content Collection ID to be purged
using a single Content Purge action.
CI-3 [MED] The CDNI Control interface should allow the Upstream
CDN to request that the Downstream CDN, including downstream
cascaded CDNs, mark an object or set of objects and/or its CDNI
metadata as "stale" and revalidate them before they are delivered
again.
CI-4 [HIGH] The CDNI Control interface shall allow the Downstream
CDN to report on the completion of these actions (by itself, and
including downstream cascaded CDNs, in a manner appropriate for
the action (e.g. synchronously or asynchronously). The
confirmation receipt should include a success or failure
indication. The failure indication along with the reason are used
if the Downstream CDN cannot delete the content in its storage.
CI-5 [MED] The CDNI Control interface should support initiation
and control by the Upstream CDN of pre-positioned CDNI metadata
acquisition by the Downstream CDN.
CI-6 [MED] The CDNI Control interface should support initiation
and control by the Upstream CDN of pre-positioned content
acquisition by the Downstream CDN.
o Section 2 outlines the model for the CI/T Interface at a high
level.
o Section 3 describes collections of Trigger Resources.
o Section 4 defines the web service provided by the dCDN.
o Section 5 lists properties of Trigger Requests and Status
Resources.
o Section 6 defines a JSON encoding for Trigger Requests and Status
Resources.
o Section 7 contains example messages.
1.1. Terminology
This document reuses the terminology defined in [RFC6707].
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2. Model for CDNI Triggers
A trigger, sent from the uCDN to the dCDN, is a request for dCDN to
do some work relating to data originating from the uCDN.
The trigger may request action on either metadata or content, the
following actions can be requested:
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.
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 MAY poll Trigger Status Resources to monitor
progress.
Requests to invalidate and purge metadata or content apply to all
variants of that data with a given URI.
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.
To trigger activity in the dCDN, the uCDN will POST to the collection
of Trigger Status Resources. If the dCDN accepts the trigger, it
creates a new Trigger Status Resource and returns its location to the
uCDN. To monitor progress, the uCDN MAY GET the Trigger Status
Resource. To cancel a trigger, or remove a trigger from the
collection once its activity has been completed, the uCDN MAY DELETE
the Trigger Status Resource.
In addition to the collection of all Trigger Status Resources for
uCDN, uCDN has access to 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.
Figure 1 is an example showing the basic message flow used by the
uCDN to trigger activity in dCDN, and for uCDN to discover the status
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of that activity. Only successful triggering is shown. Examples of
the messages are given in Section 7.
uCDN dCDN
| (1) POST http://dcdn.example.com/triggers/uCDN |
[ ] --------------------------------------------------> [ ]--+
| [ ] | (2)
| (3) HTTP 201 Response [ ]<-+
[ ] <-------------------------------------------------- [ ]
| Loc: http://dcdn.example.com/triggers/uCDN/123 |
| |
. . .
. . .
. . .
| |
| (4) GET http://dcdn.example.com/triggers/uCDN/123 |
[ ] --------------------------------------------------> [ ]
| [ ]
| (5) HTTP 200 Trigger Status Resource [ ]
[ ] <-------------------------------------------------- [ ]
| |
| |
Figure 1: Basic CDNI Message Flow for Triggers
The steps in Figure 1 are:
1. uCDN triggers action in the dCDN by posting 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.
2. dCDN authenticates the request, validates the trigger and if it
accepts the request, creates a new Trigger Status Resource.
3. dCDN responds to the uCDN with an HTTP 201 response status, and
the location of the Trigger Status Resource.
4. uCDN may repeatedly poll the Trigger Status Resource in the dCDN.
5. dCDN responds with the Trigger Status Resource, describing
progress or results of the triggered activity.
The remainder of this document describes the messages, Trigger Status
Resources, and collections of Trigger Status Resources in more
detail.
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2.1. Timing of Triggered Activity
Timing of triggered activity 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.
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, the dCDN may pre-position the new content
then immediately invalidate or purge it (as a result of the two uCDN
requests running in parallel).
2.2. Trigger Results
Each Trigger Request may operate on multiple data items. The trigger
MUST NOT be reported as "complete" unless all actions can be
completed successfully, otherwise it MUST be reported as "failed" or
"processed". The reasons for failure and URLs or Patterns affected
SHOULD be enumerated in the Trigger Status Resource. For more
detail, see section Section 4.5.
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. A trigger MAY be
reported as failed as soon as it fails in a CDN or in any of its
downstream CDNs.
3. Collections of Trigger Status Resources
As described in Section 2, Trigger Status Resources exist in 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.
To trigger activity in the dCDN, the uCDN creates a new Trigger
Status Resource by posting to the dCDN's collection of uCDN's Trigger
Status Resources. The URL of each Trigger Status Resource is
generated by the dCDN when it accepts the trigger, and returned to
the uCDN. This immediately enables the uCDN to check the status of
that trigger.
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The dCDN MUST present a different set of Trigger Status Resources to
each interconnected uCDN. Trigger Status Resources belonging to a
uCDN MUST NOT be visible to any other client. The dCDN may, for
example, achieve this by offering different collection URLs to uCDNs,
or by filtering the response based on the client uCDN.
The dCDN resource representing the collection of all the uCDN's
Trigger Status Resources is accessible to the uCDN. This collection
lists 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 4.3).
In order to allow the uCDN to check 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. The filtered collections are:
o Pending - Trigger Status Resources for triggers 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 Complete - Trigger Status Resources representing activity that
completed successfully, or for which no further status updates
will be made by the dCDN.
o Failed - Trigger Status Resources representing activity that
failed.
4. CDNI Trigger interface
This section describes an interface to enable an upstream CDN to
trigger defined activities in a downstream CDN. The interface is
intended to be independent of the set of activities defined now, or
that may be defined in future.
CI/T is built on the principles of RESTful web services. 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 servers implementing CI/T
that contain a response body SHOULD include an ETag to enable
validation of cached versions of returned resources.
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Servers 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].
The URL of the dCDN's collections of Trigger Status Resources need to
be either discovered by, or configured in, the uCDN. The mechanism
for discovery of those URLs is outside the scope of this document.
Trigger Requests are POSTed to the dCDN's collection of all Trigger
Status Resources. If the 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 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 CI/T servers are free to assign whatever structure
they desire to the URIs for CI/T resources. CI/T clients MUST NOT
make any assumptions regarding the structure of CI/T URIs or the
mapping between CI/T objects and their associated URIs. Therefore
any URIs present in the examples below 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 CI/T servers may make
use of any HTTP feature when implementing the CI/T interface. For
example, a CI/T server may make use of HTTP's caching mechanisms to
indicate that a requested response/representation has not been
modified, reducing the processing needed to determine whether the
status of triggered activity has changed.
This specification is neutral with regard to the transport below the
HTTP layer.
The dCDN MUST ensure that activity triggered by the uCDN only affects
metadata or content originating from that uCDN. Since only one CDN
can be authoritative for a given item of metadata or content, this
requirement means there cannot be any "loops" in trigger requests
between CDNs.
4.1. Creating Triggers
To create a new trigger, the uCDN makes an HTTP POST to the
unfiltered collection of its triggers. The request body of that POST
is a Trigger Request.
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The dCDN validates and authenticates that request, if it is malformed
or the uCDN does not have sufficient access rights it MAY reject the
request immediately. In this case, it MUST respond with an
appropriate 4xx HTTP error code and a resource MUST NOT be created on
dCDN.
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.
Once a Trigger Status Resource has been created the dCDN MUST NOT re-
use its location, even after that resource has been removed.
The "request" property of the Trigger Status Resource contains the
information posted in the body of the Trigger Request. 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.
If the dCDN is not able to track triggered activity, it MUST indicate
that 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.
If the dCDN is able to track 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 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".
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.
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Once created, Trigger Status Resources may be deleted by the uCDN but
not modified. The dCDN MUST reject PUT and POST requests from the
uCDN to Trigger Status Resources using HTTP status code 403.
4.2. Checking Status
The uCDN has two ways to check progress of activity it has triggered
in the dCDN, described in the following sections.
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 used by the uCDN 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 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 may chose to 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 reference (URI provided by the dCDN) for each Trigger
Status Resource it has created, it may fetch that resource at any
time.
This MAY be used to retrieve progress information, and to fetch the
result of triggered activity.
4.3. Deleting Triggers
The uCDN MAY delete Trigger Status Resources at any time, using the
HTTP DELETE method.
Once deleted, the references to a Trigger Status Resource MUST be
removed from all Trigger Status Resource collections. Subsequent
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requests for the resource MUST be handled as required by HTTP, and so
will receive responses with status 404 or 410.
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 is 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 the
DELETE is processed by the dCDN.
If an "active" 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.
Deletion of a "complete", "processed" or "failed" Trigger Status
Resource requires no processing in the dCDN other than deletion of
the resource.
4.4. Expiry of Trigger Status Resources
The dCDN MAY choose to automatically delete Trigger Status Resources
some time after they become "complete", "processed" or "failed". In
this case, the dCDN will remove the resource and respond to
subsequent requests for it with HTTP status 404 or 410.
If the dCDN performs this housekeeping, it MUST have reported the
length of time after which completed Trigger Status Resources become
stale 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" or "failed".
To ensure it has access to the status of its completed and failed
triggers, it is recommended that the uCDN's polling interval is half
the time after which records for completed activity will be
considered stale.
4.5. Error Handling
A CI/T server may reject a trigger request using HTTP status codes.
For example, 400 if the request is malformed, or 401 if the client
does not have permission to create triggers or it is trying to act on
another CDN's data.
If any part of the trigger request 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
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reasons for failure, and may be present while the trigger is still
"pending" or "active", if the trigger is still running for some URLs
or Patterns in the trigger request.
Once a request has been accepted, processing errors are reported in
the Trigger Status Resource using a list of "ErrorDesc". Each
ErrorDesc is used to report errors against one or more of the URLs or
Patterns in the trigger request.
If a surrogate affected by a trigger is offline in the dCDN, or the
dCDN is unable to pass a trigger request on to any of its cascaded
dCDNs; the dCDN SHOULD report an error if the request is abandoned.
Otherwise, it SHOULD keep the trigger in state "pending" or "active"
until it's acted upon or the uCDN chooses to cancel it. Or, if the
request is queued and the dCDN will not report further status, the
dCDN MAY report the trigger as "processed", in which case it SHOULD
also provide an estimated completion time.
Note that an "invalidate" trigger 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. This does not apply to "preposition"
or "purge" triggers.
5. Properties of Triggers
5.1. Properties of Trigger Requests
Properties of Trigger Requests are defined in the following
subsections.
Property: type
Description: This property defines the type of the trigger.
Type: TriggerType
Mandatory: Yes
Property: metadata.urls
Description: The uCDN URL for the metadata the trigger applies
to.
Type: URLs
Mandatory: No, but at least one of 'metadata.*' or 'content.*'
MUST be present and non-empty.
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Property: content.urls
Description: URLs of content data the trigger applies to, see
Section 5.1.1.
Type: URLs
Mandatory: No, but at least one of 'metadata.*' or 'content.*'
MUST be present and non-empty.
Property: content.ccid
Description: The Content Collection IDentifier of data the
trigger applies to.
Type: List of strings
Mandatory: No, but at least one of 'metadata.*' or 'content.*'
MUST be present and non-empty.
Property: metadata.patterns
Description: The metadata the trigger applies to.
Type: List of PatternMatch
Mandatory: No, but at least one of 'metadata.*' or 'content.*'
MUST be present and non-empty, and metadata.patterns MUST NOT
be present if the TriggerType is Preposition.
Property: content.patterns
Description: The content data the trigger applies to.
Type: List of PatternMatch
Mandatory: No, but at least one of 'metadata.*' or 'content.*'
MUST be present and non-empty, and content.patterns MUST NOT be
present if the TriggerType is Preposition.
5.1.1. Content URLs
To refer to content in the dCDN, the uCDN MUST present URLs in the
same form clients will use to access content in that dCDN, after
transformation to remove any surrogate-specific parts of a
302-redirect URL form. By definition, it is always possible to
locate content based on URLs in this form.
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If content URLs are transformed by an intermediate CDN in a cascade,
that intermediate CDN MUST transform URLs in trigger requests it
passes to its dCDN.
When processing trigger requests, CDNs MUST ignore the URL scheme
(http or https) in comparing URLs. For example, for an invalidate or
purge trigger, content MUST invalidated or purged regardless of the
protocol clients use to request it.
5.2. Properties of Trigger Status Resources
Property: trigger
Description: The properties of trigger request that created
this record.
Type: TriggerRequest
Mandatory: Yes
Property: ctime
Description: Time at which the request was received by the
dCDN. Time is determined by the dCDN, there is no requirement
to synchronise clocks between interconnected CDNs.
Type: AbsoluteTime
Mandatory: Yes
Property: mtime
Description: Time at which the resource was last modified.
Time is determined by the dCDN, there is no requirement to
synchronise clocks between interconnected CDNs.
Type: AbsoluteTime
Mandatory: Yes
Property: etime
Description: Estimate of the time at which the dCDN expects to
complete the activity. Time is determined by the dCDN, there
is no requirement to synchronise clocks between interconnected
CDNs.
Type: AbsoluteTime
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Mandatory: No
Property: status
Description: Current status of the triggered activity.
Type: TriggerStatus
Mandatory: Yes
Property: errors
Description: List of ErrorDesc.
Mandatory: No.
5.3. Properties of ErrorDesc
An ErrorDesc object is used to report failure for URLs and patterns
in a trigger request.
Property: error
Type: ErrorCode.
Mandatory: Yes.
Property: metadata.urls, content.urls, metadata.patterns,
content.patterns
Description: Metadata and content references copied from the
trigger request. Only those URLs and patterns to which the
error applies shall be included in each property, but those
URLs and patterns MUST be exactly as they appear in the
request, the dCDN must not generalise the URLs. (For example,
if the uCDN requests prepositioning of URLs
"http://ucdn.example.com/a" and "http://ucdn.example.com/b",
the dCDN must not generalise its error report to Pattern
"http://ucdn.example.com/*").
Mandatory: At least one of these properties is mandatory in
each ErrorDesc.
Property: description
Description: A String containing a human-readable description
of the error.
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Mandatory: No.
5.4. Properties of Trigger Collections
Property: triggers
Description: Links to Trigger Status Resources in the
collection.
Type: URLs.
Mandatory: Yes
Property: staleresourcetime
Description: The length of time for which the dCDN guarantees
to keep a completed Trigger Status Resource. After this time,
the dCDN MAY delete the resource and all references to it from
collections.
Type: 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.
5.5. Trigger Resource Simple Data Type Descriptions
This section describes the simpler data types that are used for
properties of Trigger Status resources.
5.5.1. TriggerType
This type defines the type of action being triggered, permitted
actions are:
o Preposition - a request for the dCDN to acquire metadata or
content.
o 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.
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o Purge - a request for the dCDN to erase metadata or content.
After servicing the request, the specified data MUST NOT be held
on dCDN.
5.5.2. TriggerStatus
This type describes the current status of a Trigger, possible values
are:
o Pending - the trigger has not yet been acted upon.
o Active - the trigger is currently being acted upon.
o Complete - the triggered activity completed successfully.
o Processed - the trigger has been accepted and no further status
update will be made (may be used in cases where completion cannot
be confirmed).
o Failed - the triggered activity could not be completed.
5.5.3. URLs
This type describes a set of references to metadata or content, it is
simply a list of absolute URLs.
5.5.4. AbsoluteTime
Times are expressed in seconds since the UNIX epoch.
5.5.5. ErrorCode
This type is used by dCDN to report failures in trigger processing.
o EMETA - the dCDN was unable to acquire metadata required to fulfil
the request.
o ECONTENT - the dCDN was unable to acquire content (preposition
triggers only).
o EPERM - the uCDN does not have permission to trigger the requested
activity (for example, the data is owned by another CDN).
o EREJECT - the dCDN is not willing to fulfil the request (for
example, a preposition request for content at a time when dCDN
would not accept Request Routing requests from uCDN).
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o ECDN - An internal error in the dCDN or one of its downstream
CDNs.
6. JSON Encoding of Objects
The encoding for a CI/T object is a JSON object containing a
dictionary of (key,value) pairs where the keys are the property
names, and the values are the associated property values.
The keys of the dictionary are the names of the properties associated
with the object and are therefore dependent on the specific object
being encoded (i.e. dependent on the MIME Media Type of the returned
resource). Likewise, the values associated with each key are
dependent on the specific object being encoded (i.e. dependent on the
MIME Media Type of the returned resource).
The "trigger" property of the top level JSON object lists the
requested action.
Key: trigger
Description: An object specifying the trigger type and a set of
data to act upon.
Type: A JSON object.
Mandatory: Yes.
Object keys in JSON are case sensitive and therefore any dictionary
key defined by this document (for example the names of CI/T object
properties) MUST always be represented in lowercase.
In addition to the properties of an object, the following additional
keys MAY be present.
Key: base
Description: Provides a prefix for any relative URLs in the
object. This is similar to the XML base tag [XML-BASE]. If
absent, all URLs in the remainder of the document MUST be
absolute URLs.
Type: URI
Mandatory: No
Key: _links
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Description: The relationships of this object to other
addressable objects.
Type: Array of Relationships.
Mandatory: Yes
6.1. JSON Encoding of Embedded Types
6.1.1. TriggerType
Key: type
Description: One of "preposition", "invalidate" or "purge".
Type: string
6.1.2. TriggerStatus
Key: status
Description: One of "pending", "active", "failed", "complete"
Type: string
6.1.3. PatternMatch
A PatternMatch is encoded as a JSON Object containing a string to
match and flags describing the type of match.
Key: pattern
Description: A pattern for string matching. The pattern may
contain the wildcards * and ?, where * matches any sequence of
characters (including the empty string) and ? matches exactly
one character. The three literals \ , * and ? MUST be escaped
as \\, \* and \?
Type: String
Mandatory: Yes
Key: case-sensitive
Description: Flag indicating whether or not case-sensitive
matching should be used.
Type: Boolean
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Mandatory: No, default is case-insensitive match.
Key: match-query-string
Description: Flag indicating whether or not the query string
should be included in the pattern match.
Type: Boolean
Mandatory: No, default is not to include query.
Example of case-sensitive prefix match against
"http://www.example.com/trailers/":
{
"pattern": "http://www.example.com/trailers/*",
"case-sensitive": true
}
6.1.4. ErrorDesc
ErrorDesc is encoded as a JSON object with the following keys:
Key: error
Type: ErrorCode
Mandatory: Yes
Keys: metadata.urls, content.urls
Type: Array of strings
Mandatory: At least one of metadata.* or content.* MUST be
present.
Keys: metadata.patterns, content.patterns
Type: Array of PatternMatch
Mandatory: At least one of metadata.* or content.* MUST be
present.
Key: description
Type: String
Mandatory: No.
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6.1.5. ErrorCode
One of the strings "EMETA", "ECONTENT", "EPERM", "EREJECT" or "ECDN".
6.2. MIME Media Types
Table 1 lists the MIME Media Type for the trigger request, and each
trigger object (resource) that is retrievable through the CI/T
interface.
+-------------------+--------------------------------------------+
| Data Object | MIME Media Type |
+-------------------+--------------------------------------------+
| TriggerRequest | application/cdni.ci.TriggerRequest+json |
| TriggerStatus | application/cdni.ci.TriggerStatus+json |
| TriggerCollection | application/cdni.ci.TriggerCollection+json |
+-------------------+--------------------------------------------+
Table 1: MIME Media Types for CDNI Trigger resources
7. Examples
The following sections provide examples of different CI/T objects
encoded as JSON.
No authentication is shown in the following illustrative examples, it
is anticipated that authentication mechanisms will be aligned with
other CDNI Interfaces as and when those mechanisms are defined.
Discovery of the triggers interface is out of scope of this document.
In an implementation, all 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 following
URLs are used as the location of the collections of triggers:
o Collection of all Triggers belonging to one uCDN:
http://dcdn.example.com/triggers
o Filtered collections:
Pending: http://dcdn.example.com/triggers/pending
Active: http://dcdn.example.com/triggers/active
Complete: http://dcdn.example.com/triggers/complete
Failed: http://dcdn.example.com/triggers/failed
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7.1. Creating Triggers
Examples of uCDN triggering activity in dCDN:
7.1.1. Preposition
An example of a preposition request, a POST to the "AllTriggers"
collection.
Note that "metadata.patterns" and "content.patterns" are not allowed
in a preposition trigger request.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
Content-Type: application/cdni.ci.TriggerRequest+json
Content-Length: 315
{
"trigger" : {
"type": "preposition",
"metadata.urls" : [ "http://metadata.example.com/a/b/c" ],
"content.urls" : [
"http://www.example.com/a/b/c/1",
"http://www.example.com/a/b/c/2",
"http://www.example.com/a/b/c/3",
"http://www.example.com/a/b/c/4"
]
}
}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 02 Jul 2014 18:57:19 GMT
Content-Length: 472
Content-Type: application/cdni.ci.TriggerStatus+json
Location: http://dcdn.example.com/triggers/0
Server: example-server/0.1
{
"ctime": 1404327439,
"etime": 1404327447,
"mtime": 1404327439,
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"status": "pending",
"trigger": {
"content.urls": [
"http://www.example.com/a/b/c/1",
"http://www.example.com/a/b/c/2",
"http://www.example.com/a/b/c/3",
"http://www.example.com/a/b/c/4"
],
"metadata.urls": [
"http://metadata.example.com/a/b/c"
],
"type": "preposition"
}
}
7.1.2. 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.
REQUEST:
POST /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
Content-Type: application/cdni.ci.TriggerRequest+json
Content-Length: 352
{
"trigger" : {
"type": "invalidate",
"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
}
]
}
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}
RESPONSE:
HTTP/1.1 201 Created
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Length: 551
Content-Type: application/cdni.ci.TriggerStatus+json
Location: http://dcdn.example.com/triggers/1
Server: example-server/0.1
{
"ctime": 1404327440,
"etime": 1404327448,
"mtime": 1404327440,
"status": "pending",
"trigger": {
"content.patterns": [
{
"case-sensitive": true,
"pattern": "http://www.example.com/a/b/*"
}
],
"content.urls": [
"http://www.example.com/a/index.html"
],
"metadata.patterns": [
{
"pattern": "http://metadata.example.com/a/b/*"
}
],
"type": "invalidate"
}
}
7.2. Examining Trigger Status
Once triggers have been created, the uCDN can check their status as
shown in these examples.
7.2.1. 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:
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REQUEST:
GET /triggers HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 153
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "9179988753593038498"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": [
"http://dcdn.example.com/triggers/0",
"http://dcdn.example.com/triggers/1"
]
}
7.2.2. Filtered Collections of Triggers
The filtered collections are also available to uCDN. Before the dCDN
starts processing the two triggers shown above, both will appear in
the collection of Pending Triggers, for example:
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RREQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 153
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "5012053611544832286"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
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:
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REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 56
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "2986340333785000363"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": []
}
7.2.3. 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:
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REQUEST:
GET /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 472
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "-3651695664007658154"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerStatus+json
{
"ctime": 1404327439,
"etime": 1404327447,
"mtime": 1404327439,
"status": "pending",
"trigger": {
"content.urls": [
"http://www.example.com/a/b/c/1",
"http://www.example.com/a/b/c/2",
"http://www.example.com/a/b/c/3",
"http://www.example.com/a/b/c/4"
],
"metadata.urls": [
"http://metadata.example.com/a/b/c"
],
"type": "preposition"
}
}
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REQUEST:
GET /triggers/1 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 551
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "-7664987687828084413"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerStatus+json
{
"ctime": 1404327440,
"etime": 1404327448,
"mtime": 1404327440,
"status": "pending",
"trigger": {
"content.patterns": [
{
"case-sensitive": true,
"pattern": "http://www.example.com/a/b/*"
}
],
"content.urls": [
"http://www.example.com/a/index.html"
],
"metadata.patterns": [
{
"pattern": "http://metadata.example.com/a/b/*"
}
],
"type": "invalidate"
}
}
7.2.4. Polling for Change
The uCDN may use the Entity Tags of collections or resources when
polling for change in status, as shown in the following examples:
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REQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
If-None-Match: "5012053611544832286"
RESPONSE:
HTTP/1.1 304 Not Modified
Content-Length: 0
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "5012053611544832286"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
REQUEST:
GET /triggers/0 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
If-None-Match: "-3651695664007658154"
RESPONSE:
HTTP/1.1 304 Not Modified
Content-Length: 0
Expires: Wed, 02 Jul 2014 18:58:20 GMT
Server: example-server/0.1
Etag: "-3651695664007658154"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:20 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 may look like:
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REQUEST:
GET /triggers/pending HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 56
Expires: Wed, 02 Jul 2014 18:58:24 GMT
Server: example-server/0.1
Etag: "-4471185573414616962"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:24 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": []
}
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REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 153
Expires: Wed, 02 Jul 2014 18:58:31 GMT
Server: example-server/0.1
Etag: "-1508172875796647067"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:31 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": [
"http://dcdn.example.com/triggers/0",
"http://dcdn.example.com/triggers/1"
]
}
7.2.5. Cancelling or Removing a Trigger
To request the dCDN to cancel a Trigger, the uCDN may delete the
Trigger Resource. It may also delete completed and failed triggers
to reduce the size of the collections. For example, to remove the
"preposition" request from earlier examples:
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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: Wed, 02 Jul 2014 18:57:31 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:
REQUEST:
GET /triggers/complete HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 106
Expires: Wed, 02 Jul 2014 18:58:31 GMT
Server: example-server/0.1
Etag: "-1842390246836476263"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 18:57:31 GMT
Content-Type: application/cdni.ci.TriggerCollection+json
{
"staleresourcetime": 86400,
"triggers": [
"http://dcdn.example.com/triggers/1"
]
}
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7.2.6. Error Reporting
In this example the uCDN has requested prepositioning of
"http://newsite.example.com/index.html", but the dCDN was unable to
locate metadata for that site:
REQUEST:
GET /triggers/2 HTTP/1.1
User-Agent: example-user-agent/0.1
Host: dcdn.example.com
Accept: */*
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 505
Expires: Wed, 02 Jul 2014 19:16:48 GMT
Server: example-server/0.1
Etag: "-6310233270471598826"
Cache-Control: max-age=60
Date: Wed, 02 Jul 2014 19:15:48 GMT
Content-Type: application/cdni.ci.TriggerStatus+json
{
"ctime": 1404328544,
"errors": [
{
"content.urls": [
"http://newsite.example.com/index.html"
],
"description":
"No HostIndex entry found for newsite.example.com",
"error": "EMETA"
}
],
"etime": 1404328552,
"mtime": 1404328548,
"status": "active",
"trigger": {
"content.urls": [
"http://newsite.example.com/index.html"
],
"type": "preposition"
}
}
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Internet-Draft CDN Interconnect Triggers July 2014
8. IANA Considerations
8.1. CI/T MIME Media Types
The IANA is requested to allocate the following MIME Media Types in
the MIME Media Types registry:
o application/cdni.ci.TriggerRequest
o application/cdni.ci.TriggerStatus
o application/cdni.ci.TriggerCollection
Use of these types is specified in Section 6.2 of the present
document.
9. Security Considerations
9.1. 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 trigger requests from, or reporting status
to, an authenticated CDN).
HTTP requests that attempt to access or operate on CI/T data
belonging to another CDN MUST be rejected using either HTTP "403
Forbidden" or "404 Not Found". (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, it MUST
allow each upstream that may have been responsible for acquisition of
that content to act upon it using trigger requests.)
Trigger creation requests that attempt to operate on metadata or
content not acquired from the uCDN making the request MUST be
rejected. The rejection can either be signalled to dCDN using HTTP
"403 Forbidden" or "404 Not Found", or a Trigger Status Resource can
be created with an ErrorDesc value of EPERM for any affected URLs.
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
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Internet-Draft CDN Interconnect Triggers July 2014
parties of the transaction (the uCDN and the dCDN) SHOULD use mutual
authentication.
A CI/T implementation 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.
9.2. Denial of Service
This document does not define a specific mechanism to protect against
Denial of Service (DoS) attacks on the CI/T. However, CI/T endpoints
can be protected against DoS attacks through the use of TLS transport
and/or via mechanisms outside the scope of the CI/T interface, such
as firewalling or use of Virtual Private Networks (VPNs).
10. Acknowledgements
The authors thank Kevin Ma for his ongoing input.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005.
[RFC7159] Bray, T., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, March 2014.
[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.
11.2. Informative References
[I-D.ietf-cdni-framework]
Peterson, L., Davie, B., and R. Brandenburg, "Framework
for CDN Interconnection", draft-ietf-cdni-framework-14
(work in progress), June 2014.
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Internet-Draft CDN Interconnect Triggers July 2014
[I-D.ietf-cdni-metadata]
Niven-Jenkins, B., Murray, R., Watson, G., Caulfield, M.,
Leung, K., and K. Ma, "CDN Interconnect Metadata", draft-
ietf-cdni-metadata-06 (work in progress), February 2014.
[I-D.ietf-cdni-requirements]
Leung, K. and Y. Lee, "Content Distribution Network
Interconnection (CDNI) Requirements", draft-ietf-cdni-
requirements-17 (work in progress), January 2014.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom
Syndication Format", RFC 4287, December 2005.
[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.
[XML-BASE]
Marsh, J., Ed. and R. Tobin, Ed., "XML Base (Second
Edition) - http://www.w3.org/TR/xmlbase/", January 2009.
Authors' Addresses
Rob Murray
Velocix (Alcatel-Lucent)
3 Ely Road
Milton, Cambridge CB24 6DD
UK
Email: rmurray@velocix.com
Ben Niven-Jenkins
Velocix (Alcatel-Lucent)
3 Ely Road
Milton, Cambridge CB24 6DD
UK
Email: ben@velocix.com
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