rfc9241.original   rfc9241.txt 
ALTO & CDNI WGs J. Seedorf Internet Engineering Task Force (IETF) J. Seedorf
Internet-Draft HFT Stuttgart - Univ. of Applied Sciences Request for Comments: 9241 HFT Stuttgart - Univ. of Applied Sciences
Intended status: Standards Track Y. Yang Category: Standards Track Y. Yang
Expires: 21 August 2022 Yale University ISSN: 2070-1721 Yale University
K. Ma K. Ma
Ericsson Ericsson
J. Peterson J. Peterson
NeuStar NeuStar
J. Zhang J. Zhang
Tongji University Tongji University
17 February 2022 May 2022
Content Delivery Network Interconnection (CDNI) Request Routing: CDNI Content Delivery Network Interconnection (CDNI) Request Routing: CDNI
Footprint and Capabilities Advertisement using ALTO Footprint and Capabilities Advertisement Using ALTO
draft-ietf-alto-cdni-request-routing-alto-22
Abstract Abstract
The Content Delivery Networks Interconnection (CDNI) framework in RFC The Content Delivery Networks Interconnection (CDNI) framework in RFC
6707 defines a set of protocols to interconnect CDNs to achieve 6707 defines a set of protocols to interconnect CDNs to achieve
multiple goals, including extending the reach of a given CDN. A CDNI multiple goals, including extending the reach of a given CDN. A CDNI
Request Routing Footprint & Capabilities Advertisement interface Request Routing Footprint & Capabilities Advertisement interface
(FCI) is needed to achieve the goals of a CDNI. RFC 8008 defines the (FCI) is needed to achieve the goals of a CDNI. RFC 8008 defines the
FCI semantics and provides guidelines on the FCI protocol, but the FCI semantics and provides guidelines on the FCI protocol, but the
exact protocol is not specified. This document defines a new exact protocol is not specified. This document defines a new
Application-Layer Traffic Optimization (ALTO) service, called "CDNI Application-Layer Traffic Optimization (ALTO) service, called "CDNI
Advertisement Service", that provides an implementation of the FCI, Advertisement Service", that provides an implementation of the FCI,
following the guidelines defined in RFC 8008. following the guidelines defined in RFC 8008.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79.
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Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 21 August 2022. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9241.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
2. Terminology and Background . . . . . . . . . . . . . . . . . 4 2. Terminology and Background
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Terminology
2.2. Semantics of FCI Advertisement . . . . . . . . . . . . . 5 2.2. Semantics of FCI Advertisement
2.3. ALTO Background and Benefits . . . . . . . . . . . . . . 6 2.3. ALTO Background and Benefits
3. CDNI Advertisement Service . . . . . . . . . . . . . . . . . 8 3. CDNI Advertisement Service
3.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 9 3.1. Media Type
3.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 9 3.2. HTTP Method
3.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 9 3.3. Accept Input Parameters
3.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 9 3.4. Capabilities
3.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.5. Uses
3.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 9 3.6. Response
3.7. Examples . . . . . . . . . . . . . . . . . . . . . . . . 12 3.7. Examples
3.7.1. IRD . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.7.1. IRD
3.7.2. A Basic Example . . . . . . . . . . . . . . . . . . . 15 3.7.2. A Basic Example
3.7.3. Incremental Updates . . . . . . . . . . . . . . . . . 17 3.7.3. Incremental Updates
4. CDNI Advertisement Service using ALTO Network Map . . . . . . 18 4. CDNI Advertisement Service Using ALTO Network Map
4.1. Network Map Footprint Type: altopid . . . . . . . . . . . 19 4.1. Network Map Footprint Type: altopid
4.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . 19 4.2. Examples
4.2.1. ALTO Network Map for CDNI Advertisements . . . . . . 19 4.2.1. ALTO Network Map for CDNI Advertisements
4.2.2. ALTO PID Footprints in CDNI Advertisements . . . . . 20 4.2.2. ALTO PID Footprints in CDNI Advertisements
4.2.3. Incremental Updates . . . . . . . . . . . . . . . . . 21 4.2.3. Incremental Updates
5. Filtered CDNI Advertisement using CDNI Capabilities . . . . . 23 5. Filtered CDNI Advertisement Using CDNI Capabilities
5.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 23 5.1. Media Type
5.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 23 5.2. HTTP Method
5.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 23 5.3. Accept Input Parameters
5.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 24 5.4. Capabilities
5.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.5. Uses
5.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 24 5.6. Response
5.7. Examples . . . . . . . . . . . . . . . . . . . . . . . . 25 5.7. Examples
5.7.1. A Basic Example . . . . . . . . . . . . . . . . . . . 25 5.7.1. A Basic Example
5.7.2. Incremental Updates . . . . . . . . . . . . . . . . . 26 5.7.2. Incremental Updates
6. Query Footprint Properties Using ALTO Property Map Service
6. Query Footprint Properties using ALTO Property Map Service . 28 6.1. Representing Footprint Objects as Property Map Entities
6.1. Representing Footprint Objects as Property Map 6.1.1. ASN Domain
Entities . . . . . . . . . . . . . . . . . . . . . . . . 28 6.1.2. COUNTRYCODE Domain
6.1.1. ASN Domain . . . . . . . . . . . . . . . . . . . . . 29
6.1.2. COUNTRYCODE Domain . . . . . . . . . . . . . . . . . 30
6.2. Representing CDNI Capabilities as Property Map Entity 6.2. Representing CDNI Capabilities as Property Map Entity
Properties . . . . . . . . . . . . . . . . . . . . . . . 30 Properties
6.2.1. Defining Information Resource Media Type for Property 6.2.1. Defining Information Resource Media Type for Property
Type cdni-capabilities . . . . . . . . . . . . . . . 30 Type cdni-capabilities
6.2.2. Intended Semantics of Property Type 6.2.2. Intended Semantics of Property Type cdni-capabilities
cdni-capabilities . . . . . . . . . . . . . . . . . . 31 6.3. Examples
6.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 31 6.3.1. Property Map
6.3.1. Property Map . . . . . . . . . . . . . . . . . . . . 31 6.3.2. Filtered Property Map
6.3.2. Filtered Property Map . . . . . . . . . . . . . . . . 32 6.3.3. Incremental Updates
6.3.3. Incremental Updates . . . . . . . . . . . . . . . . . 34 7. IANA Considerations
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 7.1. application/alto-cdni+json Media Type
7.1. application/alto-cdni+json Media Type . . . . . . . . . . 35 7.2. application/alto-cdnifilter+json Media Type
7.2. application/alto-cdnifilter+json Media Type . . . . . . . 36 7.3. CDNI Metadata Footprint Types Registry
7.3. CDNI Metadata Footprint Type Registry . . . . . . . . . . 38 7.4. ALTO Entity Domain Types Registry
7.4. ALTO Entity Domain Type Registry . . . . . . . . . . . . 38 7.5. ALTO Entity Property Types Registry
7.5. ALTO Entity Property Type Registry . . . . . . . . . . . 39 8. Security Considerations
8. Security Considerations . . . . . . . . . . . . . . . . . . . 39 9. References
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 40 9.1. Normative References
9.1. Normative References . . . . . . . . . . . . . . . . . . 41 9.2. Informative References
9.2. Informative References . . . . . . . . . . . . . . . . . 42 Acknowledgments
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 43 Contributors
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Authors' Addresses
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 43
1. Introduction 1. Introduction
The ability to interconnect multiple content delivery networks (CDNs) The ability to interconnect multiple content delivery networks (CDNs)
has many benefits, including increased coverage, capability, and has many benefits, including increased coverage, capability, and
reliability. The Content Delivery Networks Interconnection (CDNI) reliability. The Content Delivery Networks Interconnection (CDNI)
framework [RFC6707] defines four interfaces to interconnect CDNs: (1) framework [RFC6707] defines four interfaces to interconnect CDNs: (1)
the CDNI Request Routing Interface, (2) the CDNI Metadata Interface, the CDNI Request Routing Interface, (2) the CDNI Metadata Interface,
(3) the CDNI Logging Interface, and (4) the CDNI Control Interface. (3) the CDNI Logging Interface, and (4) the CDNI Control Interface.
Among these four interfaces, the CDNI Request Routing Interface Among these four interfaces, the CDNI Request Routing Interface
provides key functions, as specified in [RFC6707]: "The CDNI Request provides key functions, as specified in [RFC6707]:
Routing interface enables a Request Routing function in an Upstream
CDN to query a Request Routing function in a Downstream CDN to | The CDNI Request Routing interface enables a Request Routing
determine if the Downstream CDN is able (and willing) to accept the | function in an Upstream CDN to query a Request Routing function in
delegated Content Request. It also allows the Downstream CDN to | a Downstream CDN to determine if the Downstream CDN is able (and
control what should be returned to the User Agent in the redirection | willing) to accept the delegated Content Request. It also allows
message by the upstream Request Routing function." At a high level, | the Downstream CDN to control what should be returned to the User
the scope of the CDNI Request Routing Interface, therefore, contains | Agent in the redirection message by the upstream Request Routing
two main tasks: (1) determining if the dCDN (downstream CDN) is | function.
willing to accept a delegated content request, and (2) redirecting
the content request coming from a uCDN (upstream CDN) to the proper At a high level, therefore, the scope of the CDNI Request Routing
entry point or entity in the dCDN. Interface contains two main tasks: (1) determining if the dCDN
(downstream CDN) is willing to accept a delegated content request and
(2) redirecting the content request coming from a uCDN (upstream CDN)
to the proper entry point or entity in the dCDN.
Correspondingly, the Request Routing Interface is broadly divided Correspondingly, the Request Routing Interface is broadly divided
into two functionalities: (1) the CDNI Footprint & Capabilities into two functionalities: (1) the CDNI Footprint & Capabilities
Advertisement interface (FCI) defined in [RFC8008], and (2) the CDNI Advertisement interface (FCI) defined in [RFC8008] and (2) the CDNI
Request Routing Redirection interface (RI) defined in [RFC7975]. Request Routing Redirection interface (RI) defined in [RFC7975].
This document focuses on the first functionality (CDNI FCI). This document focuses on the first functionality (CDNI FCI).
Specifically, CDNI FCI allows both an advertisement from a dCDN to a Specifically, CDNI FCI allows both an Advertisement from a dCDN to a
uCDN (push) and a query from a uCDN to a dCDN (pull) so that the uCDN uCDN (push) and a query from a uCDN to a dCDN (pull) so that the uCDN
knows whether it can redirect a particular user request to that dCDN. knows whether it can redirect a particular user request to that dCDN.
A key component in defining CDNI FCI is defining objects describing A key component in defining the CDNI FCI is defining the objects that
the footprints and capabilities of a dCDN. Such objects are already describe the footprints and capabilities of a dCDN. Such objects are
defined in Section 5 of [RFC8008]. However, no protocol is defined already specified in Section 5 of [RFC8008]. However, no protocol is
to transport and update such objects between a uCDN and a dCDN. defined to transport and update such objects between a uCDN and a
dCDN.
To define such a protocol, this document specifies an extension of To define such a protocol, this document specifies an extension of
the Application-Layer Traffic Optimization (ALTO) [RFC7285] protocol the Application-Layer Traffic Optimization (ALTO) Protocol [RFC7285]
by introducing a new ALTO service called "CDNI Advertisement by introducing a new ALTO service called "CDNI Advertisement
Service". Service".
Section 2.3 discusses the benefits in using ALTO as a transport Section 2.3 discusses the benefits in using ALTO as a transport
protocol. protocol.
2. Terminology and Background 2. Terminology and Background
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119][RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
The design of CDNI FCI transport using ALTO assumes an understanding The design of CDNI FCI transport using ALTO assumes an understanding
of both FCI semantics and ALTO. Hence, this document starts with a of both FCI semantics and ALTO. Hence, this document starts with a
non-normative review for both. non-normative review of both.
2.1. Terminology 2.1. Terminology
The document uses the CDNI terms defined in [RFC6707], [RFC8006] and The document uses the CDNI terms defined in [RFC6707], [RFC8006], and
[RFC8008]. Also, the document uses the ALTO terms defined in [RFC8008]. Also, the document uses the ALTO terms defined in
[RFC7285] and [I-D.ietf-alto-unified-props-new]. This document uses [RFC7285] and [RFC9240]. This document uses the following
the following abbreviations: abbreviations:
* ALTO: Application-Layer Traffic Optimization ALTO: Application-Layer Traffic Optimization
* ASN: Autonomous System Number
* CDN: Content Delivery Network ASN: Autonomous System Number
* CDNI: CDN Interconnection CDN: Content Delivery Network
* dCDN: Downstream CDN CDNI: CDN Interconnection
* FCI: CDNI FCI, CDNI Request Routing Footprint & Capabilities dCDN: Downstream CDN
Advertisement interface
* IRD: Information Resource Directory in ALTO FCI: CDNI FCI, CDNI Request Routing Footprint & Capabilities
Advertisement interface
* PID: Provider-defined Identifier in ALTO IRD: Information Resource Directory in ALTO
* uCDN: Upstream CDN PID: Provider-defined Identifier in ALTO
uCDN: Upstream CDN
2.2. Semantics of FCI Advertisement 2.2. Semantics of FCI Advertisement
[RFC8008] defines the semantics of CDNI FCI, provides guidance on [RFC8008] defines the semantics of CDNI FCI, provides guidance on
what Footprint and Capabilities mean in a CDNI context, and specifies what footprint and capabilities mean in a CDNI context, and specifies
the requirements on the CDNI FCI transport protocol. The definitions the requirements on the CDNI FCI transport protocol. The definitions
in [RFC8008] depend on [RFC8006]. Below is a non-normative review of in [RFC8008] depend on [RFC8006]. Below is a non-normative review of
key related points of [RFC8008] and [RFC8006]. For detailed key related points of [RFC8008] and [RFC8006]. For detailed
information and normative specification, the reader should refer to information and normative specification, the reader should refer to
these two RFCs. these two RFCs.
* Multiple types of mandatory-to-implement footprints (i.e., * Multiple types of mandatory-to-implement footprints (i.e.,
ipv4cidr, ipv6cidr, asn, and countrycode) are defined in "ipv4cidr", "ipv6cidr", "asn", and "countrycode") are defined in
[RFC8006]. A "Set of IP-prefixes" can contain both full IP [RFC8006]. A "set of IP prefixes" can contain both full IP
addresses (i.e., a /32 for IPv4 or a /128 for IPv6) and IP addresses (i.e., a /32 for IPv4 or a /128 for IPv6) and IP
prefixes with an arbitrary prefix length. There must also be prefixes with an arbitrary prefix length. There must also be
support for multiple IP address versions, i.e., IPv4 and IPv6, in support for multiple IP address versions, i.e., IPv4 and IPv6, in
such a footprint. such a footprint.
* Multiple initial types of capabilities are defined in [RFC8008] * Multiple initial types of capabilities are defined in [RFC8008]
including (1) Delivery Protocol, (2) Acquisition Protocol, (3) including (1) Delivery Protocol, (2) Acquisition Protocol, (3)
Redirection Mode, (4) Capabilities related to CDNI Logging, and Redirection Mode, (4) capabilities related to CDNI Logging, and
(5) Capabilities related to CDNI Metadata. They are required in (5) capabilities related to CDNI Metadata. They are required in
all cases and, therefore, considered as mandatory-to-implement all cases and, therefore, considered as mandatory-to-implement
capabilities for all CDNI FCI implementations. capabilities for all CDNI FCI implementations.
* Footprint and capabilities are defined together and cannot be * Footprint and capabilities are defined together and cannot be
interpreted independently from each other. Specifically, interpreted independently from each other. Specifically,
[RFC8008] integrates footprint and capabilities with an approach [RFC8008] integrates footprint and capabilities with an approach
of "capabilities with footprint restrictions", by expressing of "capabilities with footprint restrictions", by expressing
capabilities on a per footprint basis. capabilities on a per footprint basis.
* Specifically, for all mandatory-to-implement footprint types, * Specifically, for all mandatory-to-implement footprint types,
footprints can be viewed as constraints for delegating requests to footprints can be viewed as constraints for delegating requests to
a dCDN: A dCDN footprint advertisement tells the uCDN the a dCDN: a dCDN footprint advertisement tells the uCDN the
limitations for delegating a request to the dCDN. For IP prefixes limitations for delegating a request to the dCDN. For IP prefixes
or Autonomous System Numbers (ASNs), the footprint signals to the or Autonomous System Numbers (ASNs), the footprint signals to the
uCDN that it should consider the dCDN a candidate only if the IP uCDN that it should consider the dCDN a candidate only if the IP
address of the request routing source falls within the prefix set address of the request routing source falls within the prefix set
or ASN, respectively. The CDNI specifications do not define how a or ASN, respectively. The CDNI specifications do not define how a
given uCDN determines what address ranges are in a particular ASN. given uCDN determines what address ranges are in a particular ASN.
Similarly, for country codes, a uCDN should only consider the dCDN Similarly, for country codes, a uCDN should only consider the dCDN
a candidate if it covers the country of the request routing a candidate if it covers the country of the request routing
source. The CDNI specifications do not define how a given uCDN source. The CDNI specifications do not define how a given uCDN
determines the country of the request routing source. Different determines the country of the request routing source. Different
types of footprint constraints can be combined together to narrow types of footprint constraints can be combined together to narrow
the dCDN candidacy, i.e., the uCDN should consider the dCDN a the dCDN candidacy, i.e., the uCDN should consider the dCDN a
candidate only if the request routing source satisfies all the candidate only if the request routing source satisfies all the
types of footprint constraints in the advertisement. types of footprint constraints in the advertisement.
* Given that a large part of Footprint and Capabilities * Given that a large part of Footprint and Capabilities
Advertisement may happen in contractual agreements, the semantics Advertisement may happen in contractual agreements, the semantics
of CDNI Footprint and Capabilities advertisement refers to of CDNI Footprint and Capabilities Advertisement refers to
answering the following question: what exactly still needs to be answering the following question: what exactly still needs to be
advertised by the CDNI FCI? For instance, updates about temporal advertised by the CDNI FCI? For instance, updates about temporal
failures of part of a footprint can be useful information to failures of part of a footprint can be useful information to
convey via the CDNI FCI. Such information would provide updates convey via the CDNI FCI. Such information would provide updates
on information previously agreed in contracts between the on information previously agreed to in contracts between the
participating CDNs. In other words, the CDNI FCI is a means for a participating CDNs. In other words, the CDNI FCI is a means for a
dCDN to provide changes/updates regarding a footprint and/or dCDN to provide changes and updates regarding a footprint and/or
capabilities that it has previously agreed to serve in a contract capabilities that it has previously agreed to serve in a contract
with a uCDN. Hence, server push and incremental encoding will be with a uCDN. Hence, server push and incremental encoding will be
necessary techniques. necessary techniques.
2.3. ALTO Background and Benefits 2.3. ALTO Background and Benefits
Application-Layer Traffic Optimization (ALTO) [RFC7285] defines an Application-Layer Traffic Optimization (ALTO) [RFC7285] defines an
approach for conveying network layer (topology) information to approach for conveying network-layer (topology) information to
"guide" the resource provider selection process in distributed "guide" the resource provider selection process in distributed
applications that can choose among several candidate resources applications that can choose among several candidate resources
providers to retrieve a given resource. Usually, it is assumed that providers to retrieve a given resource. Usually, it is assumed that
an ALTO server conveys information that these applications cannot an ALTO server conveys information that these applications cannot
measure or have difficulty measuring themselves [RFC5693]. measure or have difficulty measuring themselves [RFC5693].
Originally, ALTO was motivated by optimizing cross-ISP traffic Originally, ALTO was motivated by optimizing cross-ISP traffic
generated by P2P applications [RFC5693]. However, ALTO can also be generated by peer-to-peer applications [RFC5693]. However, ALTO can
used for improving the request routing in CDNs. In particular, also be used for improving the request routing in CDNs. In
Section 5 of [RFC7971] explicitly mentions ALTO as a candidate particular, Section 5 of [RFC7971] explicitly mentions ALTO as a
protocol to improve the selection of a CDN surrogate or origin. candidate protocol to improve the selection of a CDN surrogate or
origin.
The following reasons make ALTO a suitable candidate protocol for The following reasons make ALTO a suitable candidate protocol for
dCDN selection as part of CDNI request routing and, in particular, dCDN selection as part of CDNI request routing and, in particular,
for an FCI protocol: for an FCI protocol:
* Application Layer-oriented: ALTO is a protocol specifically * Application-Layer-oriented: ALTO is a protocol specifically
designed to improve application layer traffic (and application designed to improve application-layer traffic (and application-
layer connections among hosts on the Internet) by providing layer connections among hosts on the Internet) by providing
additional information to applications that these applications additional information to applications that these applications
could not easily retrieve themselves. This matches the need of could not easily retrieve themselves. This matches the need of
CDNI, where a uCDN wants to improve application layer CDN request CDNI, where a uCDN wants to improve application-layer CDN request
routing by using information (provided by a dCDN) that the uCDN routing by using information (provided by a dCDN) that the uCDN
could not easily obtain otherwise. Hence, ALTO can help a uCDN to could not easily obtain otherwise. Hence, ALTO can help a uCDN to
select a proper dCDN by first providing dCDNs' capabilities as select a proper dCDN by first providing dCDNs' capabilities as
well as footprints (see Section 3) and then providing costs of well as footprints (see Section 3) and then providing costs of
surrogates in a dCDN by ALTO cost maps. surrogates in a dCDN by ALTO cost maps.
* Security: The identification between uCDNs and dCDNs is an * Security: The identification between uCDNs and dCDNs is an
important requirement (see Section 8). ALTO maps can be signed important requirement (see Section 8). ALTO maps can be signed
and hence provide inherent origin protection. Please see and hence provide inherent origin protection. Please see
Section 15.1.2 of [RFC7285] for detailed protection strategies. Section 15.1.2 of [RFC7285] for detailed protection strategies.
* RESTful design: The ALTO protocol has undergone extensive * RESTful design: The ALTO Protocol has undergone extensive
revisions in order to provide a RESTful design regarding the revisions in order to provide a RESTful design regarding the
client-server interaction specified by the protocol. It is client-server interaction specified by the protocol. It is
flexible and extensible enough to handle existing and potential flexible and extensible enough to handle existing and potential
future data formats defined by CDNI. It can provide the future data formats defined by CDNI. It can provide the
consistent client-server interaction model for other existing CDNI consistent client-server interaction model for other existing CDNI
interfaces or potential future extensions and therefore reduce the interfaces or potential future extensions and therefore reduce the
learning cost for both users and developers, although they are not learning cost for both users and developers, although they are not
in the scope of this document. A CDNI FCI interface based on ALTO in the scope of this document. A CDNI FCI interface based on ALTO
would inherit this RESTful design. Please see Section 3. would inherit this RESTful design. Please see Section 3.
* Error-handling: The ALTO protocol provides extensive error- * Error handling: The ALTO Protocol provides extensive error
handling in the whole request and response process (see handling in the whole request and response process (see
Section 8.5 of [RFC7285]). A CDNI FCI interface based on ALTO Section 8.5 of [RFC7285]). A CDNI FCI interface based on ALTO
would inherit this extensive error-handling framework. Please see would inherit this extensive error-handling framework. Please see
Section 5. Section 5.
* Map Service: The semantics of an ALTO network map is an exact * Map Service: The semantics of an ALTO network map is an exact
match for the needed information to convey a footprint by a dCDN, match for the needed information to convey a footprint by a dCDN,
in particular, if such a footprint is being expressed by IP-prefix in particular, if such a footprint is being expressed by IP prefix
ranges. Please see Section 4. ranges. Please see Section 4.
* Filtered Map Service: The ALTO map filtering service would allow a * Filtered Map Service: The ALTO map filtering service would allow a
uCDN to query only for parts of an ALTO map. For example, the uCDN to query only for parts of an ALTO map. For example, the
ALTO filtered property map service can enable a uCDN to query ALTO filtered property map service can enable a uCDN to query
properties of a part of footprints efficiently. Please see properties of a part of footprints efficiently. Please see
Section 6. Section 6.
* Server-initiated notifications and incremental updates: When the * Server-initiated notifications and incremental updates: When the
footprint or the capabilities of a dCDN change (i.e., unexpectedly footprint or the capabilities of a dCDN change (i.e., unexpectedly
from the perspective of a uCDN), server-initiated notifications from the perspective of a uCDN), server-initiated notifications
would enable a dCDN to inform a uCDN about such changes directly. would enable a dCDN to inform a uCDN about such changes directly.
Consider the case where - due to failure - part of the footprint Consider the case where -- due to failure -- part of the footprint
of the dCDN is not functioning, i.e., the CDN cannot serve content of the dCDN is not functioning, i.e., the CDN cannot serve content
to such clients with reasonable QoS. Without server-initiated to such clients with reasonable QoS. Without server-initiated
notifications, the uCDN might still use a recent network and cost notifications, the uCDN might still use a recent network and cost
map from the dCDN, and therefore redirect requests to the dCDN map from the dCDN and therefore redirect requests to the dCDN that
which it cannot serve. Similarly, the possibility for incremental it cannot serve. Similarly, the possibility for incremental
updates would enable efficient conveyance of the aforementioned updates would enable efficient conveyance of the aforementioned
(or similar) status changes by the dCDN to the uCDN. The newest (or similar) status changes by the dCDN to the uCDN. The newest
design of ALTO supports server pushed incremental updates design of ALTO supports server-pushed incremental updates
[RFC8895]. [RFC8895].
* Content availability on hosts: A dCDN might want to express CDN * Content availability on hosts: A dCDN might want to express CDN
capabilities in terms of certain content types (e.g., codecs/ capabilities in terms of certain content types (e.g., codecs and/
formats, or content from certain content providers). ALTO Entity or formats, or content from certain content providers). ALTO
Property Map [I-D.ietf-alto-unified-props-new] would enable a dCDN Entity Property Map [RFC9240] would enable a dCDN to make such
to make such information available to a uCDN. This would enable a information available to a uCDN. This would enable a uCDN to
uCDN to access whether a dCDN has the capabilities for a given assess whether a dCDN has the capabilities for a given type of
type of content requested. content requested.
* Resource availability on hosts or links: The capabilities on links * Resource availability on hosts or links: The capabilities on links
(e.g., maximum bandwidth) or caches (e.g., average load) might be (e.g., maximum bandwidth) or caches (e.g., average load) might be
useful information for a uCDN for optimized dCDN selection. For useful information for a uCDN for optimized dCDN selection. For
instance, if a uCDN receives a streaming request for content with instance, if a uCDN receives a streaming request for content with
a certain bitrate, it needs to know if it is likely that a dCDN a certain bitrate, it needs to know if it is likely that a dCDN
can fulfill such stringent application-level requirements (i.e., can fulfill such stringent application-level requirements (i.e.,
can be expected to have enough consistent bandwidth) before it can be expected to have enough consistent bandwidth) before it
redirects the request. In general, if ALTO could convey such redirects the request. In general, if ALTO could convey such
information via ALTO Entity Property Map information via ALTO Entity Property Map [RFC9240], it would
[I-D.ietf-alto-unified-props-new], it would enable more enable more sophisticated means for dCDN selection with ALTO. The
sophisticated means for dCDN selection with ALTO. ALTO Path ALTO Path Vector extension [ALTO-PATH-VECTOR] is designed to allow
Vector Extension [I-D.ietf-alto-path-vector] is designed to allow
ALTO clients to query information such as capacity regions for a ALTO clients to query information such as capacity regions for a
given set of flows. given set of flows.
3. CDNI Advertisement Service 3. CDNI Advertisement Service
The ALTO protocol relies upon the ALTO Information Service framework The ALTO Protocol relies upon the ALTO information service framework,
which consists of multiple services. All ALTO services are "provided which consists of multiple services. All ALTO services are "provided
through a common transport protocol, messaging structure and through a common transport protocol; messaging structure and
encoding, and transaction model" [RFC7285]. The ALTO protocol encoding; and transaction model" [RFC7285]. The ALTO Protocol
specification defines multiple initial services, e.g., the ALTO specification defines multiple initial services, e.g., the ALTO
network map service and cost map service. network map service and cost map service.
This document defines a new ALTO service, called "CDNI Advertisement This document defines a new ALTO service, called "CDNI Advertisement
Service", which conveys JSON [RFC8259] objects of media type Service", which conveys JSON [RFC8259] objects of media type
"application/alto-cdni+json". These JSON objects are used to "application/alto-cdni+json". These JSON objects are used to
transport BaseAdvertisementObject objects defined in [RFC8008]. This transport BaseAdvertisementObject objects defined in [RFC8008]. This
document specifies how to transport such BaseAdvertisementObject document specifies how to transport such BaseAdvertisementObject
objects via the ALTO protocol with the ALTO "CDNI Advertisement objects via the ALTO Protocol with the ALTO "CDNI Advertisement
Service". Similar to other ALTO services, this document defines the Service". Similar to other ALTO services, this document defines the
ALTO information resource for the "CDNI Advertisement Service" as ALTO information resource for the "CDNI Advertisement Service" as
follows. follows.
Note that the encoding of BaseAdvertisementObject reuses the one Note that the encoding of BaseAdvertisementObject reuses the one
defined in [RFC8008] and therefore also follows the recommendations defined in [RFC8008] and therefore also follows the recommendations
of I-JSON (Internet JSON) [RFC7493], which is required by [RFC8008]. of I-JSON (Internet JSON) [RFC7493], which is required by [RFC8008].
3.1. Media Type 3.1. Media Type
skipping to change at page 10, line 26 skipping to change at line 452
CDNIAdvertisementData cdni-advertisement; CDNIAdvertisementData cdni-advertisement;
} InfoResourceCDNIAdvertisement : ResponseEntityBase; } InfoResourceCDNIAdvertisement : ResponseEntityBase;
object { object {
BaseAdvertisementObject capabilities-with-footprints<0..*>; BaseAdvertisementObject capabilities-with-footprints<0..*>;
} CDNIAdvertisementData; } CDNIAdvertisementData;
Specifically, a CDNIAdvertisementData object is a JSON object that Specifically, a CDNIAdvertisementData object is a JSON object that
includes only one property named "capabilities-with-footprints", includes only one property named "capabilities-with-footprints",
whose value is an array of BaseAdvertisementObject objects. It whose value is an array of BaseAdvertisementObject objects. It
provides capabilities with footprint restrictions for uCDN to decide provides capabilities with footprint restrictions for the uCDN to
the dCDN selection. If the value of this property is an empty array, decide the dCDN selection. If the value of this property is an empty
it means the corresponding dCDN cannot provide any mandatory-to- array, it means the corresponding dCDN cannot provide any mandatory-
implement CDNI capabilities for any footprints. to-implement CDNI capabilities for any footprints.
The syntax and semantics of BaseAdvertisementObject are well defined The syntax and semantics of BaseAdvertisementObject are well defined
in Section 5.1 of [RFC8008]. A BaseAdvertisementObject object in Section 5.1 of [RFC8008]. A BaseAdvertisementObject object
includes multiple properties, including capability-type, capability- includes multiple properties, including capability-type, capability-
value, and footprints, where footprints are defined in value, and footprints, where footprints are defined in
Section 4.2.2.2 of [RFC8006]. Section 4.2.2.2 of [RFC8006].
To be self-contained, below is an equivalent specification of To be self-contained, below is an equivalent specification of
BaseAdvertisementObject described in the ALTO-style notation (see BaseAdvertisementObject described in the ALTO-style notation (see
Section 8.2 of [RFC7285]). As mentioned above, the normative Section 8.2 of [RFC7285]). As mentioned above, the normative
skipping to change at page 11, line 7 skipping to change at line 481
Footprint footprints<0..*>; Footprint footprints<0..*>;
} BaseAdvertisementObject; } BaseAdvertisementObject;
object { object {
JSONString footprint-type; JSONString footprint-type;
JSONString footprint-value<1..*>; JSONString footprint-value<1..*>;
} Footprint; } Footprint;
For each BaseAdvertisementObject, the ALTO client MUST interpret For each BaseAdvertisementObject, the ALTO client MUST interpret
footprints appearing multiple times as if they appeared only once. footprints appearing multiple times as if they appeared only once.
If footprints in a BaseAdvertisementObject is null or empty or not If footprints in a BaseAdvertisementObject is null or empty or does
appearing, the ALTO client MUST understand that the capabilities in not appear, the ALTO client MUST understand that the capabilities in
this BaseAdvertisementObject have the "global" coverage, i.e., the this BaseAdvertisementObject have the "global" coverage, i.e., the
corresponding dCDN can provide them for any request routing source. corresponding dCDN can provide them for any request routing source.
Note: Further optimization of BaseAdvertisement objects to Note: Further optimization of BaseAdvertisementObjects to effectively
effectively provide the advertisement of capabilities with footprint provide the advertisement of capabilities with footprint restrictions
restrictions is certainly possible. For example, these two examples is certainly possible. For example, these two examples below both
below both describe that the dCDN can provide capabilities describe that the dCDN can provide capabilities ["http/1.1",
["http/1.1", "https/1.1"] for the same footprints. However, the "https/1.1"] for the same footprints. However, the latter one is
latter one is smaller in its size. smaller in its size.
EXAMPLE 1 EXAMPLE 1
{ {
"meta": {...}, "meta": {...},
"cdni-advertisement": { "cdni-advertisement": {
"capabilities-with-footprints": [ "capabilities-with-footprints": [
{ {
"capability-type": "FCI.DeliveryProtocol", "capability-type": "FCI.DeliveryProtocol",
"capability-value": { "capability-value": {
"delivery-protocols": [ "delivery-protocols": [
skipping to change at page 12, line 37 skipping to change at line 560
This document only requires the ALTO server to provide the initial This document only requires the ALTO server to provide the initial
FCI-specific CDNI Payload Types defined in [RFC8008] as the FCI-specific CDNI Payload Types defined in [RFC8008] as the
mandatory-to-implement CDNI capabilities. mandatory-to-implement CDNI capabilities.
3.7. Examples 3.7. Examples
3.7.1. IRD 3.7.1. IRD
Below is the IRD of a simple, example ALTO server. The server Below is the IRD of a simple, example ALTO server. The server
provides both base ALTO information resources (e.g., network maps) provides both base ALTO information resources (e.g., network maps)
and CDNI FCI related information resources (e.g., CDNI Advertisement and CDNI FCI-related information resources (e.g., CDNI Advertisement
resources), demonstrating a single, integrated environment. resources), demonstrating a single, integrated environment.
Specifically, the IRD announces nine information resources as Specifically, the IRD announces nine information resources as
follows: follows:
* two network maps, * two network maps,
* one CDNI Advertisement resource without dependency, * one CDNI Advertisement resource without dependency,
* one CDNI Advertisement resource depending on a network map, * one CDNI Advertisement resource depending on a network map,
skipping to change at page 18, line 44 skipping to change at line 856
data: "path": "/meta/vtag/tag", data: "path": "/meta/vtag/tag",
data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe" data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
data: }, data: },
data: { "op": "add", data: { "op": "add",
data: "path": "/cdni-advertisement/capabilities-with-footprints data: "path": "/cdni-advertisement/capabilities-with-footprints
/0/footprints/0/footprint-value/-", /0/footprints/0/footprint-value/-",
data: "value": "192.0.2.0/24" data: "value": "192.0.2.0/24"
data: } data: }
data: ] data: ]
4. CDNI Advertisement Service using ALTO Network Map 4. CDNI Advertisement Service Using ALTO Network Map
4.1. Network Map Footprint Type: altopid 4.1. Network Map Footprint Type: altopid
The ALTO protocol defines a concept called Provider-defined The ALTO Protocol defines a concept called Provider-defined
Identifier (PID) to represent a group of IPv4 or IPv6 addresses which Identifier (PID) to represent a group of IPv4 or IPv6 addresses to
can be applied the same management policy. The PID is an alternative which can be applied the same management policy. The PID is an
to the pre-defined CDNI footprint types (i.e., ipv4cidr, ipv6cidr, alternative to the predefined CDNI footprint types (i.e., "ipv4cidr",
asn, and countrycode). "ipv6cidr", "asn", and "countrycode").
To leverage this concept, this document defines a new CDNI Footprint To leverage this concept, this document defines a new CDNI Footprint
Type called "altopid". A CDNI Advertisement resource can depend on Type called "altopid". A CDNI Advertisement resource can depend on
an ALTO network map resource and use "altopid" footprints to compress an ALTO network map resource and use "altopid" footprints to compress
its CDNI Footprint Payload. its CDNI Footprint Payload.
Specifically, the "altopid" footprint type indicates that the Specifically, the "altopid" footprint type indicates that the
corresponding footprint value is a list of PIDNames as defined in corresponding footprint value is a list of PIDNames as defined in
[RFC7285]. These PIDNames are references of PIDs in a network map [RFC7285]. These PIDNames are references of PIDs in a network map
resource. Hence a CDNI Advertisement resource using "altopid" resource. Hence a CDNI Advertisement resource using "altopid"
footprints depends on a network map. For such a CDNI Advertisement footprints depends on a network map. For such a CDNI Advertisement
resource, the resource id of its dependent network map MUST be resource, the resource ID of its dependent network map MUST be
included in the "uses" field of its IRD entry, and the "dependent- included in the "uses" field of its IRD entry, and the "dependent-
vtags" field with a reference to this network map MUST be included in vtags" field with a reference to this network map MUST be included in
its response (see the example in Section 4.2.2). its response (see the example in Section 4.2.2).
4.2. Examples 4.2. Examples
The following examples use the same IRD given in Section 3.7.1. The following examples use the same IRD given in Section 3.7.1.
4.2.1. ALTO Network Map for CDNI Advertisements 4.2.1. ALTO Network Map for CDNI Advertisements
Below provides a sample network map whose resource id is "my-eu- Below provides a sample network map whose resource ID is "my-eu-
netmap". This map is referenced by the CDNI Advertisement example in netmap". This map is referenced by the CDNI Advertisement example in
Section 4.2.2. Section 4.2.2.
GET /myeunetmap HTTP/1.1 GET /myeunetmap HTTP/1.1
Host: alto.example.com Host: alto.example.com
Accept: application/alto-networkmap+json,application/alto-error+json Accept: application/alto-networkmap+json,application/alto-error+json
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Length: 344 Content-Length: 344
Content-Type: application/alto-networkmap+json Content-Type: application/alto-networkmap+json
skipping to change at page 23, line 14 skipping to change at line 1029
data: "path": "/meta/vtag/tag", data: "path": "/meta/vtag/tag",
data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe" data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
data: }, data: },
data: { "op": "remove", data: { "op": "remove",
data: "path": data: "path":
data: "/cdni-advertisement/capabilities-with-footprints data: "/cdni-advertisement/capabilities-with-footprints
/1/footprints/0/footprint-value/1" /1/footprints/0/footprint-value/1"
data: } data: }
data: ] data: ]
5. Filtered CDNI Advertisement using CDNI Capabilities 5. Filtered CDNI Advertisement Using CDNI Capabilities
Sections 3 (Section 3) and 4 (Section 4) describe CDNI Advertisement Sections 3 and 4 describe the CDNI Advertisement Service that can be
Service which can be used to enable a uCDN to get capabilities with used to enable a uCDN to get capabilities with footprint restrictions
footprint restrictions from dCDNs. However, since always getting from dCDNs. However, since always getting full CDNI Advertisement
full CDNI Advertisement resources from dCDNs is inefficient, this resources from dCDNs is inefficient, this document introduces a new
document introduces a new service named "Filtered CDNI Advertisement service named "Filtered CDNI Advertisement Service" to allow a client
Service", to allow a client to filter a CDNI Advertisement resource to filter a CDNI Advertisement resource using a client-given set of
using a client-given set of CDNI capabilities. For each entry of the CDNI capabilities. For each entry of the CDNI Advertisement
CDNI Advertisement response, an entry will only be returned to the response, an entry will only be returned to the client if it contains
client if it contains at least one of the client given CDNI at least one of the client-given CDNI capabilities. The relationship
capabilities. The relationship between a filtered CDNI Advertisement between a filtered CDNI Advertisement resource and a CDNI
resource and a CDNI Advertisement resource is similar to the Advertisement resource is similar to the relationship between a
relationship between a filtered network/cost map and a network/cost filtered network/cost map and a network/cost map.
map.
5.1. Media Type 5.1. Media Type
A filtered CDNI Advertisement resource uses the same media type A filtered CDNI Advertisement resource uses the same media type
defined for the CDNI Advertisement resource in Section 3.1: defined for the CDNI Advertisement resource in Section 3.1:
"application/alto-cdni+json". "application/alto-cdni+json".
5.2. HTTP Method 5.2. HTTP Method
A filtered CDNI Advertisement resource is requested using the HTTP A filtered CDNI Advertisement resource is requested using the HTTP
POST method. POST method.
5.3. Accept Input Parameters 5.3. Accept Input Parameters
The input parameters for a filtered CDNI Advertisement resource are The input parameters for a filtered CDNI Advertisement resource are
supplied in the entity body of the POST request. This document supplied in the entity body of the POST request. This document
specifies the input parameters with a data format indicated by the specifies the input parameters with a data format indicated by the
media type "application/alto-cdnifilter+json" which is a JSON object media type "application/alto-cdnifilter+json", which is a JSON object
of type ReqFilteredCDNIAdvertisement, where: of type ReqFilteredCDNIAdvertisement where:
object { object {
JSONString capability-type; JSONString capability-type;
JSONValue capability-value; JSONValue capability-value;
} CDNICapability; } CDNICapability;
object { object {
CDNICapability cdni-capabilities<0..*>; CDNICapability cdni-capabilities<0..*>;
} ReqFilteredCDNIAdvertisement; } ReqFilteredCDNIAdvertisement;
skipping to change at page 24, line 42 skipping to change at line 1100
There are no applicable capabilities. There are no applicable capabilities.
5.5. Uses 5.5. Uses
Same to the "uses" field of the CDNI Advertisement resource (see Same to the "uses" field of the CDNI Advertisement resource (see
Section 3.5). Section 3.5).
5.6. Response 5.6. Response
If the request is invalid, the response MUST indicate an error, using If the request is invalid, the response MUST indicate an error using
ALTO protocol error handling specified in Section 8.5 of [RFC7285]. ALTO Protocol error handling specified in Section 8.5 of [RFC7285].
Specifically, a filtered CDNI Advertisement request is invalid if: Specifically, a filtered CDNI Advertisement request is invalid if:
* the value of "capability-type" is null; * the value of "capability-type" is null;
* the value of "capability-value" is null; * the value of "capability-value" is null; or
* the value of "capability-value" is inconsistent with "capability- * the value of "capability-value" is inconsistent with "capability-
type". type".
When a request is invalid, the ALTO server MUST return an When a request is invalid, the ALTO server MUST return an
"E_INVALID_FIELD_VALUE" error defined in Section 8.5.2 of [RFC7285], "E_INVALID_FIELD_VALUE" error defined in Section 8.5.2 of [RFC7285],
and the "value" field of the error message SHOULD indicate this CDNI and the "value" field of the error message SHOULD indicate this CDNI
capability. capability.
The ALTO server returns a filtered CDNI Advertisement resource for a The ALTO server returns a filtered CDNI Advertisement resource for a
valid request. The format of a filtered CDNI Advertisement resource valid request. The format of a filtered CDNI Advertisement resource
is the same as a full CDNI Advertisement resource (See Section 3.6.) is the same as a full CDNI Advertisement resource (see Section 3.6).
The returned filtered CDNI Advertisement resource MUST contain all The returned filtered CDNI Advertisement resource MUST contain all
the BaseAdvertisementObject objects satisfying the following the BaseAdvertisementObject objects satisfying the following
condition: The CDNI capability object of each included condition: the CDNI capability object of each included
BaseAdvertisementObject object MUST follow two constraints: BaseAdvertisementObject object MUST follow two constraints:
* The "cdni-capabilities" field of the input includes a CDNI * The "cdni-capabilities" field of the input includes a CDNI
capability object X having the same capability type as it. capability object X having the same capability type as it.
* All the mandatory properties in its capability value is a superset * All the mandatory properties in its capability value is a superset
of mandatory properties in capability value of X semantically. of mandatory properties in capability value of X semantically.
See Section 5.7.1 for a concrete example. See Section 5.7.1 for a concrete example.
skipping to change at page 25, line 41 skipping to change at line 1148
filtering that is requested by an ALTO client. filtering that is requested by an ALTO client.
5.7. Examples 5.7. Examples
The following examples use the same IRD example as in Section 3.7.1. The following examples use the same IRD example as in Section 3.7.1.
5.7.1. A Basic Example 5.7.1. A Basic Example
This example filters the full CDNI Advertisement resource in This example filters the full CDNI Advertisement resource in
Section 3.7.2 by selecting only the http/1.1 delivery protocol Section 3.7.2 by selecting only the http/1.1 delivery protocol
capability. Only the second BaseAdvertisementObjects in the full capability. Only the second BaseAdvertisementObject in the full
resource will be returned because the second object's capability is resource will be returned because the second object's capability is
http/1.1 and https/1.1 delivery protocols which is the superset of http/1.1 and https/1.1 delivery protocols, which is the superset of
https/1.1 delivery protocol. https/1.1 delivery protocol.
POST /cdnifci/filtered HTTP/1.1 POST /cdnifci/filtered HTTP/1.1
Host: alto.example.com Host: alto.example.com
Accept: application/alto-cdni+json Accept: application/alto-cdni+json
Content-Type: application/cdnifilter+json Content-Type: application/cdnifilter+json
Content-Length: 176 Content-Length: 176
{ {
"cdni-capabilities": [ "cdni-capabilities": [
skipping to change at page 28, line 6 skipping to change at line 1259
data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe" data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
data: }, data: },
data: { "op": "add", data: { "op": "add",
data: "path": data: "path":
data: "/cdni-advertisement/capabilities-with-footprints data: "/cdni-advertisement/capabilities-with-footprints
/0/footprints/0/footprint-value/-", /0/footprints/0/footprint-value/-",
data: "value": "192.0.2.0/24" data: "value": "192.0.2.0/24"
data: } data: }
data: ] data: ]
6. Query Footprint Properties using ALTO Property Map Service 6. Query Footprint Properties Using ALTO Property Map Service
Besides the requirement of retrieving footprints of given Besides the requirement of retrieving footprints of given
capabilities, another common requirement for uCDN is to query CDNI capabilities, another common requirement for uCDN is to query CDNI
capabilities of given footprints. capabilities of given footprints.
Considering each footprint as an entity with properties including Considering each footprint as an entity with properties including
CDNI capabilities, a natural way to satisfy this requirement is to CDNI capabilities, a natural way to satisfy this requirement is to
use the ALTO property map as defined in use the ALTO property map as defined in [RFC9240]. This section
[I-D.ietf-alto-unified-props-new]. This section describes how ALTO describes how ALTO clients look up properties for individual
clients look up properties for individual footprints. First, it footprints. First, it describes how to represent footprint objects
describes how to represent footprint objects as entities in the ALTO as entities in the ALTO property map. Then it describes how to
property map. Then it describes how to represent footprint represent footprint capabilities as entity properties in the ALTO
capabilities as entity properties in the ALTO property map. Finally, property map. Finally, it provides examples of the full property map
it provides examples of the full property map and the filtered and the filtered property map supporting CDNI capabilities, and their
property map supporting CDNI capabilities, and their incremental incremental updates.
updates.
6.1. Representing Footprint Objects as Property Map Entities 6.1. Representing Footprint Objects as Property Map Entities
A footprint object has two properties: footprint-type and footprint- A footprint object has two properties: footprint-type and footprint-
value. A footprint-value is an array of footprint values conforming value. A footprint-value is an array of footprint values conforming
to the specification associated with the registered footprint type to the specification associated with the registered footprint type
("ipv4cidr", "ipv6cidr", "asn", "countrycode", and "altopid"). ("ipv4cidr", "ipv6cidr", "asn", "countrycode", and "altopid").
Considering each ALTO entity defined in Considering each ALTO entity defined in [RFC9240] also has two
[I-D.ietf-alto-unified-props-new] also has two properties: entity properties: entity domain type and domain-specific identifier, a
domain type and domain-specific identifier, a straightforward straightforward approach to represent a footprint as an ALTO entity
approach to represent a footprint as an ALTO entity is to represent is to represent its footprint-type as an entity domain type, and its
its footprint-type as an entity domain type, and its footprint value footprint value as a domain-specific identifier.
as a domain-specific identifier.
Each existing footprint type can be represented as an entity domain Each existing footprint type can be represented as an entity domain
type as follows: type as follows:
* According to [I-D.ietf-alto-unified-props-new], "ipv4" and "ipv6" * According to [RFC9240], "ipv4" and "ipv6" are two predefined
are two predefined entity domain types, which can be used to entity domain types, which can be used to represent "ipv4cidr" and
represent "ipv4cidr" and "ipv6cidr" footprints respectively. Note "ipv6cidr" footprints respectively. Note that both "ipv4" and
that both "ipv4" and "ipv6" domains can include not only "ipv6" domains can include not only hierarchical addresses but
hierarchical addresses but also individual addresses. Therefore, also individual addresses. Therefore, a "ipv4cidr" or "ipv6cidr"
a "ipv4cidr" or "ipv6cidr" footprint with the longest prefix can footprint with the longest prefix can also be represented by an
also be represented by an individual address entity. When the individual address entity. When the uCDN receives a property map
uCDN receives a property map with individual addresses in an with individual addresses in an "ipv4" or "ipv6" domain, it can
"ipv4" or "ipv6" domain, it can translate them as corresponding translate them as corresponding "ipv4cidr" or "ipv6cidr"
"ipv4cidr" or "ipv6cidr" footprints with the longest prefix. footprints with the longest prefix.
* "pid" is also a predefined entity domain type, which can be used * "pid" is also a predefined entity domain type, which can be used
to represent "altopid" footprints. Note that "pid" is a resource- to represent "altopid" footprints. Note that "pid" is a resource-
specific entity domain. To represent an "altopid" footprint, the specific entity domain. To represent an "altopid" footprint, the
specifying information resource of the corresponding "pid" entity specifying information resource of the corresponding "pid" entity
domain MUST be the dependent network map used by the CDNI domain MUST be the dependent network map used by the CDNI
Advertisement resource providing this "altopid" footprint. Advertisement resource providing this "altopid" footprint.
* However, no existing entity domain type can represent "asn" and * However, no existing entity domain type can represent "asn" and
"countrycode" footprints. To represent footprint-type "asn" and "countrycode" footprints. To represent footprint-type "asn" and
"countrycode", this document registers two new entity domains in "countrycode", this document registers two new entity domains in
Section 7 in addition to the ones in Section 7 in addition to the ones in [RFC9240].
[I-D.ietf-alto-unified-props-new].
Here is an example of representing a footprint object of "ipv4cidr" Here is an example of representing a footprint object of "ipv4cidr"
type as a set of "ipv4" entities in the ALTO property map. The type as a set of "ipv4" entities in the ALTO property map. The
representation of the footprint object of "ipv6cidr" type is similar. representation of the footprint object of "ipv6cidr" type is similar.
{ "footprint-type": "ipv4cidr", { "footprint-type": "ipv4cidr",
"footprint-value": ["192.0.2.0/24", "198.51.100.0/24"] "footprint-value": ["192.0.2.0/24", "198.51.100.0/24"]
} --> "ipv4:192.0.2.0/24", "ipv4:198.51.100.0/24" } --> "ipv4:192.0.2.0/24", "ipv4:198.51.100.0/24"
And here is an example of corresponding footprint object of And here is an example of the corresponding footprint object of
"ipv4cidr" type represented by an individual address in an "ipv4" "ipv4cidr" type represented by an individual address in an "ipv4"
domain in the ALTO property map. The translation of the entities in domain in the ALTO property map. The translation of the entities in
an "ipv6" domain is similar. an "ipv6" domain is similar.
"ipv4:203.0.113.100" --> { "ipv4:203.0.113.100" --> {
"footprint-type": "ipv4cidr", "footprint-type": "ipv4cidr",
"footprint-value": ["203.0.113.100/32"] "footprint-value": ["203.0.113.100/32"]
} }
6.1.1. ASN Domain 6.1.1. ASN Domain
skipping to change at page 30, line 33 skipping to change at line 1375
6.1.2.3. Hierarchy and Inheritance 6.1.2.3. Hierarchy and Inheritance
There is no hierarchy or inheritance for properties associated with There is no hierarchy or inheritance for properties associated with
country codes. country codes.
6.2. Representing CDNI Capabilities as Property Map Entity Properties 6.2. Representing CDNI Capabilities as Property Map Entity Properties
This document defines a new entity property type called "cdni- This document defines a new entity property type called "cdni-
capabilities". An ALTO server can provide a property map resource capabilities". An ALTO server can provide a property map resource
mapping the "cdni-capablities" entity property type for a CDNI mapping the "cdni-capabilities" entity property type for a CDNI
Advertisement resource that it provides to an "ipv4", "ipv6", "asn" Advertisement resource that it provides to an "ipv4", "ipv6", "asn",
or "countrycode" entity domain. or "countrycode" entity domain.
6.2.1. Defining Information Resource Media Type for Property Type cdni- 6.2.1. Defining Information Resource Media Type for Property Type cdni-
capabilities capabilities
The entity property type "cdni-capabilities" allows defining The entity property type "cdni-capabilities" allows defining
resource-specific entity properties. When resource-specific entity resource-specific entity properties. When resource-specific entity
properties are defined with entity property type "cdni-capabilities", properties are defined with entity property type "cdni-capabilities",
the defining information resource for a "cdni-capabilities" property the defining information resource for a "cdni-capabilities" property
MUST be a CDNI Advertisement resource provided by the ALTO server. MUST be a CDNI Advertisement resource provided by the ALTO server.
The media type of the defining information resource for a "cdni- The media type of the defining information resource for a "cdni-
capabilities" property is therefore: capabilities" property is therefore:
application/alto-cdni+json application/alto-cdni+json
6.2.2. Intended Semantics of Property Type cdni-capabilities 6.2.2. Intended Semantics of Property Type cdni-capabilities
A "cdni-capabilities" property for an entity is to indicate all the The purpose of a "cdni-capabilities" property for an entity is to
CDNI capabilities that a corresponding CDNI Advertisement resource indicate all the CDNI capabilities that a corresponding CDNI
provides for the footprint represented by this entity. Thus, the Advertisement resource provides for the footprint represented by this
value of a "cdni-capabilities" property MUST be a JSON array. Each entity. Thus, the value of a "cdni-capabilities" property MUST be a
element in a "cdni-capabilities" property MUST be an JSON object as JSON array. Each element in a "cdni-capabilities" property MUST be a
format of CDNICapability (see Section 5.3). The value of a "cdni- JSON object as format of CDNICapability (see Section 5.3). The value
capabilities" property for an "ipv4", "ipv6", "asn", "countrycode" or of a "cdni-capabilities" property for an "ipv4", "ipv6", "asn",
"altopid" entity MUST include all the CDNICapability objects "countrycode", or "altopid" entity MUST include all the
satisfying the following conditions: (1) they are provided by the CDNICapability objects satisfying the following conditions: (1) they
defining CDNI Advertisement resource; and (2) the represented are provided by the defining CDNI Advertisement resource, and (2) the
footprint object of this entity is in their footprint restrictions. represented footprint object of this entity is in their footprint
restrictions.
6.3. Examples 6.3. Examples
The following examples use the same IRD example given by The following examples use the same IRD example given by
Section 3.7.1. Section 3.7.1.
6.3.1. Property Map 6.3.1. Property Map
This example shows a full property map in which entities are This example shows a full property map in which entities are
footprints and entities' property is "cdni-capabilities". footprints and entities' property is "cdni-capabilities".
skipping to change at page 36, line 14 skipping to change at line 1628
Security considerations: Security considerations:
Security considerations related to the generation and consumption Security considerations related to the generation and consumption
of ALTO Protocol messages are discussed in Section 15 of of ALTO Protocol messages are discussed in Section 15 of
[RFC7285]. [RFC7285].
Interoperability considerations: Interoperability considerations:
N/A N/A
Published specification: Published specification:
Section 3 of RFCthis Section 3 of RFC 9241
Applications that use this media type: Applications that use this media type:
ALTO servers and ALTO clients [RFC7285] either stand alone or are ALTO servers and ALTO clients [RFC7285] either stand alone or are
embedded within other applications that provides CDNI interfaces embedded within other applications that provide CDNI interfaces
for uCDNs or dCDNs. for uCDNs or dCDNs.
Fragment identifier considerations: Fragment identifier considerations:
N/A N/A
Additional information: Additional information:
Magic number(s): N/A Magic number(s): N/A
File extension(s): N/A File extension(s): N/A
skipping to change at page 36, line 44 skipping to change at line 1658
Intended usage: Intended usage:
COMMON COMMON
Restrictions on usage: Restrictions on usage:
N/A N/A
Author: Author:
See Authors' Addresses section. See Authors' Addresses section.
Change controller: Change controller:
Internet Engineering Task Force (mailto:iesg@ietf.org). Internet Engineering Task Force (iesg@ietf.org)
7.2. application/alto-cdnifilter+json Media Type 7.2. application/alto-cdnifilter+json Media Type
Type name: Type name:
application application
Subtype name: Subtype name:
alto-cdnifilter+json alto-cdnifilter+json
Required parameters: Required parameters:
skipping to change at page 37, line 24 skipping to change at line 1687
Security considerations: Security considerations:
Security considerations related to the generation and consumption Security considerations related to the generation and consumption
of ALTO Protocol messages are discussed in Section 15 of of ALTO Protocol messages are discussed in Section 15 of
[RFC7285]. [RFC7285].
Interoperability considerations: Interoperability considerations:
N/A N/A
Published specification: Published specification:
Section 5 of RFCthis Section 5 of RFC 9241
Applications that use this media type: Applications that use this media type:
ALTO servers and ALTO clients [RFC7285] either stand alone or are ALTO servers and ALTO clients [RFC7285] either stand alone or are
embedded within other applications that provides CDNI interfaces embedded within other applications that provide CDNI interfaces
for uCDNs or dCDNs and supports CDNI capability-based filtering. for uCDNs or dCDNs and supports CDNI capability-based filtering.
Fragment identifier considerations: Fragment identifier considerations:
N/A N/A
Additional information: Additional information:
Magic number(s): N/A Magic number(s): N/A
File extension(s): N/A File extension(s): N/A
skipping to change at page 38, line 6 skipping to change at line 1717
Intended usage: Intended usage:
COMMON COMMON
Restrictions on usage: Restrictions on usage:
N/A N/A
Author: Author:
See Authors' Addresses section. See Authors' Addresses section.
Change controller: Change controller:
Internet Engineering Task Force (mailto:iesg@ietf.org). Internet Engineering Task Force (iesg@ietf.org)
7.3. CDNI Metadata Footprint Type Registry
This document updates the CDNI Metadata Footprint Types Registry 7.3. CDNI Metadata Footprint Types Registry
created by Section 7.2 of [RFC8006]. A new footprint type is to be
registered, listed in Table 1.
+================+=====================+======================+ This document updates the "CDNI Metadata Footprint Types" registry
| Footprint Type | Description | Specification | created by Section 7.2 of [RFC8006]. A new footprint type, which is
+================+=====================+======================+ listed in Table 1, has been registered.
| altopid | A list of PID names | Section 4 of RFCthis |
+----------------+---------------------+----------------------+
Table 1: CDNI Metadata Footprint Type +================+=====================+=====================+
| Footprint Type | Description | Reference |
+================+=====================+=====================+
| altopid | A list of PID names | RFC 9241, Section 4 |
+----------------+---------------------+---------------------+
[RFC Editor: Please replace RFCthis with the published RFC number for Table 1: CDNI Metadata Footprint Type
this document.]
7.4. ALTO Entity Domain Type Registry 7.4. ALTO Entity Domain Types Registry
This document updates the ALTO Entity Domain Type Registry created by This document updates the "ALTO Entity Domain Types" registry created
Section 11.2 of [I-D.ietf-alto-unified-props-new]. Two new entity by Section 11.2 of [RFC9240]. Two new entity domain types, which are
domain types are to be registered, listed in Table 2. listed in Table 2, have been registered.
+=============+============+=============+=============+=========+ +=============+============+=============+=============+=========+
| Identifier | Entity | Hierarchy & | Media Type | Mapping | | Identifier | Entity | Hierarchy | Media Type | Mapping |
| | Address | Inheritance | of Defining | to ALTO | | | Identifier | and | of Defining | to ALTO |
| | Encoding | | Resource | Address | | | Encoding | Inheritance | Resource | Address |
| | | | | Type | | | | | | Type |
+=============+============+=============+=============+=========+ +=============+============+=============+=============+=========+
| asn | See | None | None | false | | asn | See RFC | None | None | false |
| | 9241, | | | |
| | Section | | | | | | Section | | | |
| | 6.1.1.2 of | | | | | | 6.1.1.2 | | | |
| | RFCthis | | | |
+-------------+------------+-------------+-------------+---------+ +-------------+------------+-------------+-------------+---------+
| countrycode | See | None | None | false | | countrycode | See RFC | None | None | false |
| | 9241, | | | |
| | Section | | | | | | Section | | | |
| | 6.1.2.2 of | | | | | | 6.1.2.2 | | | |
| | RFCthis | | | |
+-------------+------------+-------------+-------------+---------+ +-------------+------------+-------------+-------------+---------+
Table 2: Additional ALTO Entity Domain Types Table 2: Additional ALTO Entity Domain Types
[RFC Editor: Please replace RFCthis with the published RFC number for 7.5. ALTO Entity Property Types Registry
this document.]
7.5. ALTO Entity Property Type Registry
This document updates the ALTO Entity Property Type Registry created This document updates the "ALTO Entity Property Types" registry
by Section 11.3 of [I-D.ietf-alto-unified-props-new]. A new entity created by Section 11.3 of [RFC9240]. A new entity property type,
property type is to be registered, listed in Table 3. which is listed in Table 3, has been registered.
+===================+====================+===================+ +===================+====================+===================+
| Identifier | Intended Semantics | Media Type of | | Identifier | Intended Semantics | Media Type of |
| | | Defining Resource | | | | Defining Resource |
+===================+====================+===================+ +===================+====================+===================+
| cdni-capabilities | Section 6.2 of | application/alto- | | cdni-capabilities | See RFC 9241, | application/alto- |
| | RFCthis | cdni+json | | | Section 6.2 | cdni+json |
+-------------------+--------------------+-------------------+ +-------------------+--------------------+-------------------+
Table 3: Additional ALTO Entity Property Type Table 3: Additional ALTO Entity Property Type
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
8. Security Considerations 8. Security Considerations
As an extension of the base ALTO protocol [RFC7285], this document As an extension of the base ALTO Protocol [RFC7285], this document
fits into the architecture of the base protocol. And hence Security fits into the architecture of the base protocol, and hence Security
Considerations of the base protocol (Section 15 of [RFC7285]) fully Considerations of the base protocol (Section 15 of [RFC7285]) fully
apply when this extension is provided by an ALTO server. apply when this extension is provided by an ALTO server.
In the context of CDNI Advertisement, the following security risk In the context of CDNI Advertisement, the following security risk
scenarios should be considered: scenarios should be considered:
* For authenticity and integrity of ALTO information, an attacker * Authenticity and integrity of ALTO information: an attacker may
may disguise itself as an ALTO server for a dCDN (e.g., by disguise itself as an ALTO server for a dCDN (e.g., by starting a
starting a man-in-the-middle attack), and provide false man-in-the-middle attack) and provide false capabilities and
capabilities and footprints to a uCDN using the CDNI Advertisement footprints to a uCDN using the CDNI Advertisement Service. Such
service. Such false information may lead a uCDN to (1) select an false information may lead a uCDN to (1) select an incorrect dCDN
incorrect dCDN to serve user requests, or (2) skip uCDNs in good to serve user requests or (2) skip uCDNs in good conditions. To
conditions. To address this risk, protection strategies in address this risk, protection strategies in Section 15.1.2 of
Section 15.1.2 of [RFC7285] can be applied. [RFC7285] can be applied.
* For potential undesirable guidance from authenticated ALTO * Potential undesirable guidance from authenticated ALTO
information, a dCDN can provide a uCDN with limited capabilities information: a dCDN can provide a uCDN with limited capabilities
and smaller footprint coverage so that the dCDN can avoid and smaller footprint coverage so that the dCDN can avoid
transferring traffic for a uCDN which they should have to transferring traffic for a uCDN that they should have to transfer.
transfer. To reduce this risk, the protection strategies in To reduce this risk, the protection strategies in Section 15.2.2
Section 15.2.2 of [RFC7285] can be considered. of [RFC7285] can be considered.
* For confidentiality and privacy of ALTO information, footprint * Confidentiality and privacy of ALTO information: footprint
properties integrated with ALTO property maps may expose network properties integrated with ALTO property maps may expose network
location identifiers (e.g., IP addresses or fine-grained PIDs). location identifiers (e.g., IP addresses or fine-grained PIDs).
To address this risk, the protection strategy for risk types (1) To address this risk, the protection strategy for risk types (1)
and (3) as described in Section 15.3 of [RFC7285] can be and (3) as described in Section 15.3 of [RFC7285] can be
considered. considered.
* For availability of ALTO services, an attacker may conduct service * For availability of ALTO services, an attacker may conduct
degradation attacks using services defined in this document to service-degradation attacks using services defined in this
disable ALTO services of a network. It may request potentially document to disable ALTO services of a network. It may request
large, full CDNI Advertisement resources from an ALTO server in a potentially large, full CDNI Advertisement resources from an ALTO
dCDN continuously, to consume the bandwidth resources of that ALTO server in a dCDN continuously in order to consume the bandwidth
server. It may also query filtered property map services with resources of that ALTO server. It may also query filtered
many smaller individual footprints, to consume the computation property map services with many smaller individual footprints in
resources of the ALTO server. To mitigate these risks, the order to consume the computation resources of the ALTO server. To
protection strategies in Section 15.5.2 of [RFC7285] can be mitigate these risks, the protection strategies in Section 15.5.2
applied. of [RFC7285] can be applied.
Although protection strategies as described in Section 15 of Although protection strategies as described in Section 15 of
[RFC7285] should be applied to address aforementioned security and [RFC7285] should be applied to address aforementioned security and
privacy considerations, two special cases need to be included as privacy considerations, two special cases need to be included as
follows: follows:
* As required by section 7 of [RFC8008], * As required by Section 7 of [RFC8008],
"All protocols that implement these capabilities and footprint | All protocols that implement these capabilities and footprint
advertisement objects are REQUIRED to provide integrity and | advertisement objects are REQUIRED to provide integrity and
authentication services." | authentication services.
Therefore, the uCDN (ALTO Client) MUST be authenticated to the Therefore, the uCDN (ALTO Client) MUST be authenticated to the
dCDN (ALTO Server). And the dCDN (ALTO Server) MUST support HTTP dCDN (ALTO Server). And the dCDN (ALTO Server) MUST support HTTP
Digest Authentication and MAY also support TLS mutual Digest Authentication and MAY also support TLS mutual
authentication. The authentication method will need to be authentication. The authentication method will need to be
negotiated out of band and is out of scope for this document, as negotiated out of band and is out of scope for this document, as
is the approach for provisioning and managing these credentials. is the approach for provisioning and managing these credentials.
* One specific information leakage risk introduced by this document * One specific information leakage risk introduced by this document
could not be addressed by these strategies. In particular, if a cannot be addressed by these strategies. In particular, if a dCDN
dCDN signs agreements with multiple uCDNs without any isolation, signs agreements with multiple uCDNs without any isolation, this
this dCDN may disclose extra information of one uCDN to another dCDN may disclose extra information of one uCDN to another one.
one. In that case, one uCDN may redirect requests which should In that case, one uCDN may redirect requests which should not have
not have to be served by this dCDN to it. to be served by this dCDN to it.
To reduce the risk, a dCDN SHOULD isolate full/filtered CDNI To reduce the risk, a dCDN SHOULD isolate full/filtered CDNI
Advertisement resources for different uCDNs. It could consider Advertisement resources for different uCDNs. It could consider
generating URIs of different full/filtered CDNI Advertisement generating URIs of different full/filtered CDNI Advertisement
resources by hashing its company ID, a uCDN's company ID as well resources by hashing its company ID, a uCDN's company ID as well
as their agreements. A dCDN SHOULD avoid exposing all full/ as their agreements. A dCDN SHOULD avoid exposing all full/
filtered CDNI Advertisement resources in one of its IRDs. filtered CDNI Advertisement resources in one of its IRDs.
9. References 9. References
9.1. Normative References
[I-D.ietf-alto-unified-props-new] 9.1. Normative References
Roome, W., Randriamasy, S., Yang, Y. R., Zhang, J. J., and
K. Gao, "An ALTO Extension: Entity Property Maps", Work in
Progress, Internet-Draft, draft-ietf-alto-unified-props-
new-22, 25 January 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-alto-
unified-props-new-22>.
[ISO3166-1] [ISO3166-1]
ISO (International Organization for Standardization), ., International Organization for Standardization, "Codes for
"ISO 3166-1: Codes for the representation of names of the representation of names of countries and their
countries and their subdivisions -- Part 1: Country subdivisions -- Part 1: Country codes", ISO 3166-1:2020,
codes", 2020. August 2020.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet [RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793, Autonomous System (AS) Number Space", RFC 6793,
DOI 10.17487/RFC6793, December 2012, DOI 10.17487/RFC6793, December 2012,
<https://www.rfc-editor.org/rfc/rfc6793>. <https://www.rfc-editor.org/info/rfc6793>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S., [RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
Previdi, S., Roome, W., Shalunov, S., and R. Woundy, Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
"Application-Layer Traffic Optimization (ALTO) Protocol", "Application-Layer Traffic Optimization (ALTO) Protocol",
RFC 7285, DOI 10.17487/RFC7285, September 2014, RFC 7285, DOI 10.17487/RFC7285, September 2014,
<https://www.rfc-editor.org/rfc/rfc7285>. <https://www.rfc-editor.org/info/rfc7285>.
[RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493, [RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493,
DOI 10.17487/RFC7493, March 2015, DOI 10.17487/RFC7493, March 2015,
<https://www.rfc-editor.org/rfc/rfc7493>. <https://www.rfc-editor.org/info/rfc7493>.
[RFC8006] Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma, [RFC8006] Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
"Content Delivery Network Interconnection (CDNI) "Content Delivery Network Interconnection (CDNI)
Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016, Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
<https://www.rfc-editor.org/rfc/rfc8006>. <https://www.rfc-editor.org/info/rfc8006>.
[RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg, [RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
R., and K. Ma, "Content Delivery Network Interconnection R., and K. Ma, "Content Delivery Network Interconnection
(CDNI) Request Routing: Footprint and Capabilities (CDNI) Request Routing: Footprint and Capabilities
Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016, Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
<https://www.rfc-editor.org/rfc/rfc8008>. <https://www.rfc-editor.org/info/rfc8008>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259, Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017, DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/rfc/rfc8259>. <https://www.rfc-editor.org/info/rfc8259>.
[RFC8895] Roome, W. and Y. Yang, "Application-Layer Traffic [RFC8895] Roome, W. and Y. Yang, "Application-Layer Traffic
Optimization (ALTO) Incremental Updates Using Server-Sent Optimization (ALTO) Incremental Updates Using Server-Sent
Events (SSE)", RFC 8895, DOI 10.17487/RFC8895, November Events (SSE)", RFC 8895, DOI 10.17487/RFC8895, November
2020, <https://www.rfc-editor.org/rfc/rfc8895>. 2020, <https://www.rfc-editor.org/info/rfc8895>.
[RFC9240] Roome, W., Randriamasy, S., Yang, Y., Zhang, J., and K.
Gao, "ALTO Extension: Entity Property Maps", RFC 9240,
DOI 10.17487/RFC9240, May 2022,
<https://www.rfc-editor.org/info/rfc9240>.
9.2. Informative References 9.2. Informative References
[I-D.ietf-alto-path-vector] [ALTO-PATH-VECTOR]
Gao, K., Lee, Y., Randriamasy, S., Yang, Y. R., and J. J. Gao, K., Lee, Y., Randriamasy, S., Yang, Y. R., and J. J.
Zhang, "An ALTO Extension: Path Vector", Work in Progress, Zhang, "An ALTO Extension: Path Vector", Work in Progress,
Internet-Draft, draft-ietf-alto-path-vector-21, 2 February Internet-Draft, draft-ietf-alto-path-vector-25, 20 March
2022, <https://datatracker.ietf.org/doc/html/draft-ietf- 2022, <https://datatracker.ietf.org/doc/html/draft-ietf-
alto-path-vector-21>. alto-path-vector-25>.
[RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic [RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic
Optimization (ALTO) Problem Statement", RFC 5693, Optimization (ALTO) Problem Statement", RFC 5693,
DOI 10.17487/RFC5693, October 2009, DOI 10.17487/RFC5693, October 2009,
<https://www.rfc-editor.org/rfc/rfc5693>. <https://www.rfc-editor.org/info/rfc5693>.
[RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content [RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
Distribution Network Interconnection (CDNI) Problem Distribution Network Interconnection (CDNI) Problem
Statement", RFC 6707, DOI 10.17487/RFC6707, September Statement", RFC 6707, DOI 10.17487/RFC6707, September
2012, <https://www.rfc-editor.org/rfc/rfc6707>. 2012, <https://www.rfc-editor.org/info/rfc6707>.
[RFC7971] Stiemerling, M., Kiesel, S., Scharf, M., Seidel, H., and [RFC7971] Stiemerling, M., Kiesel, S., Scharf, M., Seidel, H., and
S. Previdi, "Application-Layer Traffic Optimization (ALTO) S. Previdi, "Application-Layer Traffic Optimization (ALTO)
Deployment Considerations", RFC 7971, Deployment Considerations", RFC 7971,
DOI 10.17487/RFC7971, October 2016, DOI 10.17487/RFC7971, October 2016,
<https://www.rfc-editor.org/rfc/rfc7971>. <https://www.rfc-editor.org/info/rfc7971>.
[RFC7975] Niven-Jenkins, B., Ed. and R. van Brandenburg, Ed., [RFC7975] Niven-Jenkins, B., Ed. and R. van Brandenburg, Ed.,
"Request Routing Redirection Interface for Content "Request Routing Redirection Interface for Content
Delivery Network (CDN) Interconnection", RFC 7975, Delivery Network (CDN) Interconnection", RFC 7975,
DOI 10.17487/RFC7975, October 2016, DOI 10.17487/RFC7975, October 2016,
<https://www.rfc-editor.org/rfc/rfc7975>. <https://www.rfc-editor.org/info/rfc7975>.
Acknowledgments Acknowledgments
The authors thank Matt Caulfield, Danny Alex Lachos Perez, Daryl The authors thank Matt Caulfield, Danny Alex Lachos Perez, Daryl
Malas and Sanjay Mishra for their timely reviews and invaluable Malas, and Sanjay Mishra for their timely reviews and invaluable
comments. Big thanks also to ALTO WG Chairs (Qin Wu and Vijay comments. Big thanks also to the ALTO WG Chairs (Qin Wu and Vijay
Gurbani), and all the directorate reviewers and IESG reviewers Gurbani), all the directorate reviewers, and the IESG reviewers
(Martin Duke, Erik Kline, Martin Vigoureux, Murray Kucherawy, Roman (Martin Duke, Erik Kline, Martin Vigoureux, Murray Kucherawy, Roman
Danyliw, Zaheduzzaman Sarker, Eric Vyncke, and Francesca Palombini), Danyliw, Zaheduzzaman Sarker, √Čric Vyncke, and Francesca Palombini),
for their thorough reviews, discussions, guidance and shepherding, for their thorough reviews, discussions, guidance, and shepherding,
that further improve this document. which further improve this document.
Jan Seedorf has been partially supported by the GreenICN project Jan Seedorf has been partially supported by the GreenICN project
(GreenICN: Architecture and Applications of Green Information Centric (GreenICN: Architecture and Applications of Green Information Centric
Networking), a research project supported jointly by the European Networking), a research project supported jointly by the European
Commission under its 7th Framework Program (contract no. 608518) and Commission under its 7th Framework Program (contract no. 608518) and
the National Institute of Information and Communications Technology the National Institute of Information and Communications Technology
(NICT) in Japan (contract no. 167). The views and conclusions (NICT) in Japan (contract no. 167). The views and conclusions
contained herein are those of the authors and should not be contained herein are those of the authors and should not be
interpreted as necessarily representing the official policies or interpreted as necessarily representing the official policies or
endorsements, either expressed or implied, of the GreenICN project, endorsements, either expressed or implied, of the GreenICN project,
the European Commission, or NICT. the European Commission, or NICT.
This document has also been supported by the Coordination Support This document has also been supported by the Coordination Support
Action entitled 'Supporting European Experts Presence in Action entitled 'Supporting European Experts Presence in
lnternational Standardisation Activities in ICT' ("StandlCT.eu") International Standardisation Activities in ICT' (StandICT.eu
funded by the European Commission under the Horizon 2020 Programme <https://www.standict.eu/>) funded by the European Commission under
with Grant Agreement no. 780439. The views and conclusions contained the Horizon 2020 Programme with Grant Agreement no. 780439. The
herein are those of the authors and should not be interpreted as views and conclusions contained herein are those of the authors and
necessarily representing the official policies or endorsements, should not be interpreted as necessarily representing the official
either expressed or implied, of the European Commission. policies or endorsements, either expressed or implied, of the
European Commission.
Contributors Contributors
Xiao Shawn Lin Xiao Shawn Lin
Huawei Huawei
2222 Newjinqiao Rd 2222 Newjinqiao Rd
Shanghai Shanghai
200125 200125
China China
Phone: +86-15316812351 Phone: +86-15316812351
skipping to change at page 44, line 4 skipping to change at line 1985
Xiao Shawn Lin Xiao Shawn Lin
Huawei Huawei
2222 Newjinqiao Rd 2222 Newjinqiao Rd
Shanghai Shanghai
200125 200125
China China
Phone: +86-15316812351 Phone: +86-15316812351
Email: x.shawn.lin@gmail.com Email: x.shawn.lin@gmail.com
Authors' Addresses Authors' Addresses
Jan Seedorf Jan Seedorf
HFT Stuttgart - Univ. of Applied Sciences HFT Stuttgart - Univ. of Applied Sciences
Schellingstrasse 24 Schellingstrasse 24
70174 Stuttgart 70174 Stuttgart
Germany Germany
Phone: +49-0711-8926-2801 Phone: +49-0711-8926-2801
Email: jan.seedorf@hft-stuttgart.de Email: jan.seedorf@hft-stuttgart.de
Y. Richard Yang Y. Richard Yang
Yale University Yale University
51 Prospect Street 51 Prospect Street
New Haven, CT 06511 New Haven, CT 06511
United States of America United States of America
Phone: +1-203-432-6400 Phone: +1-203-432-6400
Email: yry@cs.yale.edu Email: yry@cs.yale.edu
URI: http://www.cs.yale.edu/~yry/ URI: http://www.cs.yale.edu/~yry/
Kevin J. Ma Kevin J. Ma
Ericsson Ericsson
43 Nagog Park 43 Nagog Park
Acton, MA 01720 Acton, MA 01720
United States of America United States of America
Phone: +1-978-844-5100 Phone: +1-978-844-5100
Email: kevin.j.ma.ietf@gmail.com Email: kevin.j.ma.ietf@gmail.com
Jon Peterson Jon Peterson
NeuStar NeuStar
1800 Sutter St Suite 570 1800 Sutter St., Suite 570
Concord, CA 94520 Concord, CA 94520
United States of America United States of America
Email: jon.peterson@neustar.biz Email: jon.peterson@neustar.biz
Jingxuan Jensen Zhang Jingxuan Jensen Zhang
Tongji University Tongji University
4800 Cao'an Hwy 4800 Cao'an Hwy
Shanghai Shanghai
201804 201804
China China
Email: jingxuan.zhang@tongji.edu.cn Email: jingxuan.zhang@tongji.edu.cn
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