Internet DRAFT - draft-ietf-cdni-additional-footprint-types
draft-ietf-cdni-additional-footprint-types
Network Working Group N. Sopher
Internet-Draft Qwilt
Updates: 8008 (if approved) S. Mishra
Intended status: Standards Track Verizon
Expires: 24 December 2023 22 June 2023
Content Delivery Network Interconnection (CDNI) Footprint Types:
Subdivision Code and Footprint Union
draft-ietf-cdni-additional-footprint-types-12
Abstract
Open Caching architecture is a use case of Content Delivery Networks
Interconnection (CDNI) in which the commercial Content Delivery
Network (CDN) is the upstream CDN (uCDN) and the ISP caching layer
serves as the downstream CDN (dCDN). This document supplements the
CDNI Metadata footprint types defined in RFC 8006. The footprint
types defined in this document can be used for footprint objects as
part of the Metadata interface (MI) defined in RFC 8006 and for the
Footprint & Capabilities Advertisement interface (FCI) defined in RFC
8008. By defining the "footprintunion" footprint type, this document
updates RFC 8008, allowing an additive semantic over the narrowing
semantics defined in Appendix B of RFC 8008. This document also
supplements RFC 9241 with relevant ALTO entity domain types. The
defined footprint types are derived from requirements raised by Open
Caching but are also applicable to CDNI use cases in general.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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 https://datatracker.ietf.org/drafts/current/.
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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 24 December 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. CDNI Metadata Additional Footprint Types . . . . . . . . . . 4
2.1. CDNI Metadata "subdivisioncode" Footprint Type . . . . . 4
2.1.1. CDNI Metadata "subdivisioncode" Data Type . . . . . . 4
2.1.1.1. CDNI Metadata "subdivisioncode" Data Type
Description . . . . . . . . . . . . . . . . . . . . 4
2.1.2. CDNI Metadata "subdivisioncode" Footprint Type
Description . . . . . . . . . . . . . . . . . . . . . 4
2.2. CDNI Metadata "footprintunion" Footprint Type . . . . . . 5
2.2.1. CDNI Metadata "footprintunion" Data Type . . . . . . 6
2.2.2. CDNI Metadata "footprintunion" Footprint Type
Description . . . . . . . . . . . . . . . . . . . . . 7
3. ALTO Property Map Service Entity . . . . . . . . . . . . . . 8
3.1. SUBDIVISIONCODE Domain . . . . . . . . . . . . . . . . . 8
3.1.1. Entity Domain Type . . . . . . . . . . . . . . . . . 9
3.1.2. Domain-Specific Entity Identifiers . . . . . . . . . 9
3.1.3. Hierarchy and Inheritance . . . . . . . . . . . . . . 9
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
4.1. CDNI Metadata Footprint Types . . . . . . . . . . . . . . 9
4.2. ALTO Entity Domain Types . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . 10
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7.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
The Streaming Video Technology Alliance [SVTA] is a global
association that works to solve streaming video challenges in an
effort to improve end-user experience and adoption. The Open Caching
Working Group [OCWG] of the SVTA is focused on the delegation of
video delivery requests from commercial Content Delivery Networks
(CDNs) to a caching layer at the ISP's network. Open Caching
architecture is a specific use case of Content Delivery Networks
Interconnection (CDNI) where the commercial CDN is the upstream CDN
(uCDN) and the ISP caching layer is the downstream CDN (dCDN). The
Open Caching Request Routing Specification [OC-RR] defines the
Request Routing process and the interfaces that are required for its
provisioning. This document defines and registers CDNI Footprint and
Capabilities objects [RFC8008] that are required for Open Caching
Request Routing.
For consistency with other CDNI documents this document follows the
CDNI convention of uCDN (upstream CDN) and dCDN (downstream CDN) to
represent the commercial CDN and ISP caching layer respectively.
This document registers two CDNI Metadata footprint types (section
7.2 of [RFC8006]) for the defined objects:
* Subdivision code footprint type (e.g., for a dCDN advertising a
footprint that is specific to a State in the USA)
* Footprint union footprint type (for a dCDN advertising a footprint
that consists of a group built from multiple footprints types,
e.g., both IPv4 and IPv6 client subnets)
1.1. Terminology
The following terms are used throughout this document:
* CDN - Content Delivery Network
Additionally, this document reuses the terminology defined in
[RFC6707], [RFC7336], [RFC8006], and [RFC8008]. Specifically, we use
the following CDNI acronyms:
* uCDN, dCDN - Upstream CDN and Downstream CDN respectively (see
[RFC7336] )
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2. CDNI Metadata Additional Footprint Types
Section 5 of [RFC8008] describes the Footprint & Capabilities
Advertisement interface (FCI) Capability Advertisement object, which
includes an array of CDNI footprint objects. Each such object has a
footprint type and a footprint value, as described in section 4.2.2.2
of [RFC8006]. This document defines additional footprint types,
beyond those mentioned in CDNI metadata [RFC8006].
2.1. CDNI Metadata "subdivisioncode" Footprint Type
Section 4.3.8 of [RFC8006] specifies the "countrycode" footprint type
for listing [ISO3166-1] alpha-2 codes. Using footprint objects of
this type, one can define an FCI Capability Advertisement object
footprint constraint that matches a specific country. Herein is
defined the "subdivisioncode" simple data type, as well as a
footprint type allowing the dCDN to define constraints matching
geographic areas with better granularity, specifically using the
[ISO3166-2] country subdivision codes.
2.1.1. CDNI Metadata "subdivisioncode" Data Type
The "subdivisioncode" data type specified in Section 2.1.1.1,
describes a country specific subdivision using an [ISO3166-2] code.
The data type is added to the list of data types described in section
4.3 of [RFC8006] that are used as properties of CDNI Metadata
objects.
2.1.1.1. CDNI Metadata "subdivisioncode" Data Type Description
An [ISO3166-2] code in lowercase. Each code consists of two parts
separated by a hyphen. As per [ISO3166-2], the first part is the
[ISO3166-1] code of the country, and the second part is a string of
up to three alphanumeric characters.
Type: String
Example subdivision codes:
"ca-on"
"us-ny"
2.1.2. CDNI Metadata "subdivisioncode" Footprint Type Description
The "subdivisioncode" simple data type specified in Section 2.1.1, is
added to the data types listed as footprint types in section 4.2.2.2
of [RFC8006].
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Below is an example using a footprint object of type
"subdivisioncode". The footprint object in this example creates a
constraint that matches clients in the state of either New Jersey or
New York, USA (ISO [ISO3166-2] codes "US-NJ" and "US-NY"
respectively).
{
"capabilities": [
{
"capability-type": <CDNI capability object type>,
"capability-value": <CDNI capability object>,
"footprints": [
{
"footprint-type": "subdivisioncode",
"footprint-value": ["us-nj", "us-ny"]
}
]
}
]
}
Figure 1: Illustration of subdivision-code footprint advertisement
2.2. CDNI Metadata "footprintunion" Footprint Type
As described in section 5 of [RFC8008], the FCI Capability
Advertisement object includes an array of CDNI footprint objects.
Appendix B of [RFC8008] specifies the semantics of a footprint
objects array as a multiple, additive, footprint constraints. This
implies that the advertisement of different footprint types narrows
the dCDN's candidacy cumulatively.
Sections 4.3.5 and 4.3.6 of [RFC8006] specify the IPv4 CIDR and the
IPv6 CIDR footprint types, respectively, for listing IP unscoped
address blocks. Using footprint objects of these types, one can
define FCI Capability Advertisement object footprint constraints that
match IPv4 or IPv6 clients. However, the described "narrowing"
semantic of the footprint objects array, as described in Appendix B
of [RFC8008], prevents the usage of these objects together to create
a footprint constraint that matches IPv4 clients together with IPv6
clients.
Below is an example for an attempt at creating an object matching
IPv4 clients of subnet "192.0.2.0/24", as well as IPv6 clients of
subnet "2001:db8::/32". Such a definition results in an empty list
of clients, as the constraints are additives and a client address
cannot be both IPv4 and IPv6.
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{
"capabilities": [
{
"capability-type": <CDNI capability object type>,
"capability-value": <CDNI capability object>,
"footprints": [
{
"footprint-type": "ipv4cidr",
"footprint-value": ["192.0.2.0/24"]
},
{
"footprint-type": "ipv6cidr",
"footprint-value": ["2001:db8::/32"]
}
]
}
]
}
Figure 2: Example of narrowing semantic illustrating
advertisement of a null footprint
To overcome the described limitation and allow a list of footprint
constraints that match both IPv4 and IPv6 client subnets, this
document defines the "footprintunion" footprint type. This footprint
type allows the collection of multiple footprint-objects into a
unified object. Therefore it resolves the above limitation and can
be particularly applicable to unify semantically related objects, for
example, an IPv4 CIDR together with an IPv6 CIDR or a country code
together with a subdivisoncode.
Note: to avoid implementation complexity, a "footprintunion" MUST NOT
list any "footprintunion" as a value. As a union of unions is simply
a union, this syntactic restriction does not result with any semantic
limitation.
2.2.1. CDNI Metadata "footprintunion" Data Type
The "footprintunion" data type is based on the footprint object
already defined in section 4.2.2.2 of [RFC8006]. The footprint value
for a "footprintunion" object is an array of footprint objects, where
the footprint objects MUST be of any footprint type other than
"footprintunion".
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2.2.2. CDNI Metadata "footprintunion" Footprint Type Description
The "footprintunion" data type specified in Section 2.2.1, is added
to the data types listed as footprint types in section 4.2.2.2 of
[RFC8006].
Below is an example using a footprint union combining both IPv4 and
IPv6 client subnets.
{
"capabilities": [
{
"capability-type": <CDNI capability object type>,
"capability-value": <CDNI capability object>,
"footprints": [
{
"footprint-type": "footprintunion",
"footprint-value": [
{
"footprint-type": "ipv4cidr",
"footprint-value": ["192.0.2.0/24"]
},
{
"footprint-type": "ipv6cidr",
"footprint-value": ["2001:db8::/32"]
}
]
}
]
}
]
}
Figure 3: Example of an advertisement of footprint union for
multiple CIDR footprint types
The footprint union also enables composing a country code and
subdivision code based footprint objects. In the example below we
create a constraint covering autonomous system 64496 within the US
(ISO [ISO3166-1] alpha-2 code "US") and the Ontario province of
Canada (ISO [ISO3166-2] code "CA-ON").
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{
"capabilities": [
{
"capability-type": <CDNI capability object type>,
"capability-value": <CDNI capability object>,
"footprints": [
{
"footprint-type": "asn",
"footprint-value": ["as64496"]
},
{
"footprint-type": "footprintunion",
"footprint-value": [
{
"footprint-type": "countrycode",
"footprint-value": ["us"]
},
{
"footprint-type": "subdivisioncode",
"footprint-value": ["ca-on"]
}
]
}
]
}
]
}
Figure 4: Example of an advertisement of footprint union for multiple
geographical footprint types
3. ALTO Property Map Service Entity
Section 6 of [RFC9241] describes how to represent footprint objects
as entities in the ALTO property map. The approach is to represent
the footprint type as an entity domain type of the ALTO entity, and
the footprint value as its domain-specific identifier. [RFC9241]
further refers to the representation of footprint objects of types
"asn" and "countrycode". Here we extend this definition to the
"subdivisioncode" footprint type.
3.1. SUBDIVISIONCODE Domain
The SUBDIVISIONCODE domain associates property values that defines
codes for the names of the principal subdivisions.
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3.1.1. Entity Domain Type
The entity domain type of the SUBDIVISIONCODE domain is
"subdivisioncode" (in lowercase).
3.1.2. Domain-Specific Entity Identifiers
The entity identifier of an entity in a SUBDIVISIONCODE is encoded as
an alpha-2 [ISO3166-1] country code, followed by a separator and up
to three alphanumeric characters.
3.1.3. Hierarchy and Inheritance
There is no hierarchy or inheritance for properties associated with
subdivision codes.
4. IANA Considerations
4.1. CDNI Metadata Footprint Types
Section 7.2 of [RFC8006] specifies the "CDNI Metadata Footprint
Types" subregistry within the "Content Delivery Network
Interconnection (CDNI) Parameters" registry.
This document requests the registration of the two additional
footprint types as defined in Section 2.1 and Section 2.2 :
+=================+=====================================+===========+
| Footprint Type | Description | Reference |
+=================+=====================================+===========+
| subdivisioncode | [ISO3166-2] ISO 3166-2 country | RFCthis |
| | subdivision code: alpha-2 | |
| | country code, followed by a | |
| | hyphen-minus, and up to 3 | |
| | characters from A-Z;0-9 as a | |
| | code within the country. | |
+-----------------+-------------------------------------+-----------+
| footprintunion | A combination of other | RFCthis |
| | footprint objects | |
+-----------------+-------------------------------------+-----------+
Table 1
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
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4.2. ALTO Entity Domain Types
Section 12.3 of [RFC9240] creates the "ALTO Entity Domain Types"
registry.
This document requests the registration of an additional ALTO Entity
Domain Types:
+=================+============+=============+==========+=========+
| Identifier | Entity | Hierarchy | Media | Mapping |
| | Identifier | and | Type of | to ALTO |
| | Encoding | Inheritance | Defining | Address |
| | | | Resource | Type |
+=================+============+=============+==========+=========+
| subdivisioncode | See | None | None | false |
| | RFCthis, | | | |
| | Section | | | |
| | 3.1.2 | | | |
+-----------------+------------+-------------+----------+---------+
Table 2
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
5. Security Considerations
This specification is in accordance with the CDNI Metadata and the
CDNI Request Routing: Footprint and Capabilities Semantics. As such,
it is subject to the security and confidentiality considerations as
defined in Section 8 of [RFC8006] and in Section 7 of [RFC8008]
respectively.
6. Acknowledgements
The authors would like to express their gratitude to Ori Finkelman
and Kevin J. Ma for their guidance and reviews throughout the
development of this document. We would also like to thank all the
Area Directors for their review and feedback in improving this
document.
7. References
7.1. Normative References
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[ISO3166-1]
ISO, "Codes for the representation of names of countries
and their subdivisions -- Part 1: Country code",
ISO 3166-1:2020, Edition 4, August 2020,
<https://www.iso.org/standard/72482.html>.
[ISO3166-2]
ISO, "Codes for the representation of names of countries
and their subdivisions -- Part 2: Country subdivision
code", ISO 3166-2:2020, Edition 4, August 2020,
<https://www.iso.org/standard/72483.html>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8006] Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
"Content Delivery Network Interconnection (CDNI)
Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
<https://www.rfc-editor.org/info/rfc8006>.
[RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
R., and K. Ma, "Content Delivery Network Interconnection
(CDNI) Request Routing: Footprint and Capabilities
Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
<https://www.rfc-editor.org/info/rfc8008>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC9240] Roome, W., Randriamasy, S., Yang, Y., Zhang, J., and K.
Gao, "An Extension for Application-Layer Traffic
Optimization (ALTO): Entity Property Maps", RFC 9240,
DOI 10.17487/RFC9240, July 2022,
<https://www.rfc-editor.org/info/rfc9240>.
[RFC9241] Seedorf, J., Yang, Y., Ma, K., Peterson, J., and J. Zhang,
"Content Delivery Network Interconnection (CDNI) Footprint
and Capabilities Advertisement Using Application-Layer
Traffic Optimization (ALTO)", RFC 9241,
DOI 10.17487/RFC9241, July 2022,
<https://www.rfc-editor.org/info/rfc9241>.
7.2. Informative References
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[OC-RR] Finkelman, O., Ed., Hofmann, J., Klein, E., Mishra, S.,
Ma, K., Sahar, D., and B. Zurat, "Open Caching - Request
Routing Functional Specification", Version 2.0, 15 January
2021, <https://www.svta.org/product/open-cache-request-
routing-functional-specification/>.
[OCWG] "Open Caching Home Page", <https://opencaching.svta.org/>.
[RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
Distribution Network Interconnection (CDNI) Problem
Statement", RFC 6707, DOI 10.17487/RFC6707, September
2012, <https://www.rfc-editor.org/info/rfc6707>.
[RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
August 2014, <https://www.rfc-editor.org/info/rfc7336>.
[SVTA] "Streaming Video Technology Alliance Home Page",
<https://www.svta.org/>.
Authors' Addresses
Nir B. Sopher
Qwilt
6, Ha'harash
Hod HaSharon
4524079
Israel
Email: nir@apache.org
Sanjay Mishra
Verizon
13100 Columbia Pike
Silver Spring, MD 20904
United States of America
Email: sanjay.mishra@verizon.com
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