Internet Engineering Task Force (IETF) K. Ma
Request for Comments: 7736 Ericsson
Category: Informational December 2015
ISSN: 2070-1721
Content Delivery Network Interconnection (CDNI) Media Type Registration
Abstract
This document defines the standard media type used by the Content
Delivery Network Interconnection (CDNI) protocol suite, including the
registration procedure and recommended usage of the required payload-
type parameter.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/RFC 7736.
Copyright Notice
Copyright (c) 2015 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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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RFC 7736 CDNI Media Type December 2015
Table of Contents
1. Introduction and Scope . . . . . . . . . . . . . . . . . . . 2
2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
2.1. CDNI Media Type . . . . . . . . . . . . . . . . . . . . . 3
2.2. CDNI Payload-Types Parameters Registry . . . . . . . . . 5
3. Security Considerations . . . . . . . . . . . . . . . . . . . 6
4. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Normative References . . . . . . . . . . . . . . . . . . 6
4.2. Informative References . . . . . . . . . . . . . . . . . 6
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction and Scope
The Content Delivery Network Interconnection (CDNI) working group is
developing a set of protocols to enable the interconnection of
multiple content delivery networks (CDNs), as discussed in [RFC 6770].
The CDNI protocol suite consists of multiple HTTP-based interfaces,
many of which transfer various payloads encoded in JSON (JavaScript
Object Notation) [RFC 7159]. The main interfaces (i.e., CDNI Control
interface, CDNI Footprint & Capabilities Advertisement interface,
CDNI Request Routing Redirection interface, CDNI Metadata interface,
and CDNI Logging interface) are described in [RFC 7336]. It is
desirable to be able to indicate the type of object carried in the
HTTP entity-body without having to register separate media types for
each CDNI object. To accomplish this aim, this document defines a
single new media type for CDNI that includes a required payload-type
parameter. A separate registry of CDNI payload-type parameters is
also defined. CDNI protocol specifications may register interface-
specific payload types, specifying the payload encoding and parsing
semantics for that message (e.g., JSON serialization for a CDNI
metadata object). The same payload-type parameter may also be used
as references for other purposes (e.g., referencing CDNI metadata
objects from CDNI capability advertisement objects).
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2. IANA Considerations
This section contains the CDNI media type registration as well as the
payload-type parameter registry definition for IANA.
2.1. CDNI Media Type
Type name: application
Subtype name: cdni
Required parameters:
ptype
The required parameter "ptype" describes the type of CDNI
message contained in the message payload, as registered in the
"Content Delivery Network Interconnection (CDNI) Parameters"
registry (Section 2.2) defined below.
Optional parameters: none
Encoding considerations:
The CDNI protocol suite includes interfaces with encoded messages
that may be 8bit or binary, as well as generic logging information
that may be 7bit or binary.
Security considerations:
CDNI interfaces that return encoded data may be (mis)interpreted
if parsed by non-CDNI or non-compliant CDNI implementations. In
addition, CDNI logging information is likely to transfer large
amounts of data that may overload unexpecting clients. The
individual CDNI interface specifications provide more detailed
analysis of security and privacy concerns, and define the
requirements for authentication, authorization, confidentiality,
integrity, and privacy for each interface.
The application/cdni media type is a generic media type to be used
by multiple CDNI interfaces for transporting different types of
control and logging information. Proper validation of message
data requires parsing and understanding the ptype parameter and
the associated data encoding. Failure to properly validate
payloads may allow data extrusion under the auspices of the
application/cdni media type.
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Interoperability considerations:
The required ptype field is intended to fully describe the
structure and parsing of CDNI messages, as enforced by the ptype
registry designated expert.
Published specification: RFC 7736
Applications that use this media type:
CDNI is intended for use between interconnected CDNs for sharing
configuration and logging data, as well as for issuing content
management and redirection requests.
Fragment identifier considerations: N/A
Additional information: N/A
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): N/A
Macintosh file type code(s): N/A
Person & email address to contact for further information:
Kevin Ma <kevin.j.ma@ericsson.com>
Intended usage: LIMITED USE
Restrictions on usage:
This media type is intended only for use in CDNI protocol message
exchanges.
Author: IETF CDNI working group
Change controller: IETF CDNI working group
Provisional registration: no
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2.2. CDNI Payload-Types Parameters Registry
IANA has created a new "CDNI Payload Types" subregistry within the
"Content Delivery Network Interconnection (CDNI) Parameters"
registry. The "CDNI Payload Types" namespace defines the valid
values for the required "ptype" parameter of the "application/cdni"
media type. The CDNI payload type is an ASCII string value that
consists of only visible (printing) characters but excludes equal
signs (=), double quotes ("), and semicolons (;). It will not exceed
256 characters in length. The following Augmented Backus-Naur Form
(ABNF) definition of the CDNI payload type is provided for clarity
[RFC 5234]
ptype = 1*256(ptype-char)
ptype-char = %x21 / %x23-3A / %x3C / %x3E-7E
; Includes ALPHA, DIGIT, and other printables
; Excludes equal signs (=), double quotes ("), semicolons (;)
Additions to the "CDNI Payload Types" namespace will be made via
"Specification Required" as defined in [RFC 5226]. The designated
expert will verify that new type definitions do not duplicate
existing type definitions (in name or functionality), prevent
gratuitous additions to the namespace, and prevent any additions to
the namespace that would impair the interoperability of CDNI
implementations. The designated expert will review the
specification, even if it is a Standards Track RFC, to verify that it
contains the following information:
o The review will verify that the specification contains a
reasonably defined purpose for the new payload type. A reasonably
defined purpose will relate to an existing or proposed CDNI
interface and will not duplicate the functionality of any existing
CDNI protocol feature without specifying a rational reason (e.g.,
updating an obsolete feature), a method for detecting and handling
conflicts (e.g., a versioning system with prioritization matrix),
and a suggested migration path (e.g., deprecation of the
overlapped feature, or justification for co-existence).
o The review will verify that the specification contains information
as to which CDNI interface the new payload type pertains or
affects. The payload type may be applicable to multiple CDNI
interfaces, but the justification for the new payload type will
include a reasonable relationship to at least one Standards Track
CDNI interface.
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o The review will verify that the specification contains sufficient
detail about the data encoding (e.g., JSON serialization for new
CDNI metadata or capability advertisement objects, or ABNF and
description for new CDNI logging file formats) to allow senders
and receivers of the new payload type to implement compliant and
interoperable payload parsers.
The registry contains the payload type and the specification
describing the payload type. The registry will initially be
unpopulated.
+--------------+---------------+
| Payload Type | Specification |
+--------------+---------------+
+--------------+---------------+
3. Security Considerations
See the portion of Section 2.1 labeled "Security considerations".
4. References
4.1. Normative References
[RFC 5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC 5226, May 2008,
<http://www.rfc-editor.org/info/RFC 5226>.
[RFC 5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC 5234, January 2008,
<http://www.rfc-editor.org/info/RFC 5234>.
4.2. Informative References
[RFC 6770] Bertrand, G., Ed., Stephan, E., Burbridge, T., Eardley,
P., Ma, K., and G. Watson, "Use Cases for Content Delivery
Network Interconnection", RFC 6770, DOI 10.17487/RFC 6770,
November 2012, <http://www.rfc-editor.org/info/RFC 6770>.
[RFC 7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC 7159, March
2014, <http://www.rfc-editor.org/info/RFC 7159>.
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[RFC 7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC 7336,
August 2014, <http://www.rfc-editor.org/info/RFC 7336>.
Acknowledgments
This document is the culmination of the efforts of many in the CDNI
working group, including (in alphabetical order): Francois Le
Faucheur, Daryl Malas, Rob Murray, Ben Niven-Jenkins, Iuniana
Oprescu, Jon Peterson, and Jan Seedorf.
Author's Address
Kevin J. Ma
Ericsson
43 Nagog Park
Acton, MA 01720
United States
Phone: +1 978-844-5100
Email: kevin.j.ma@ericsson.com
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