rfc9240v1.txt   rfc9240.txt 
Internet Engineering Task Force (IETF) W. Roome Internet Engineering Task Force (IETF) W. Roome
Request for Comments: 9240 S. Randriamasy Request for Comments: 9240 S. Randriamasy
Category: Standards Track Nokia Bell Labs Category: Standards Track Nokia Bell Labs
ISSN: 2070-1721 Y. Yang ISSN: 2070-1721 Y. Yang
Yale University Yale University
J. Zhang J. Zhang
Tongji University Tongji University
K. Gao K. Gao
Sichuan University Sichuan University
May 2022 June 2022
An ALTO Extension: Entity Property Maps An Extension for Application-Layer Traffic Optimization (ALTO): Entity
Property Maps
Abstract Abstract
This document specifies an extension to the base Application-Layer This document specifies an extension to the base Application-Layer
Traffic Optimization (ALTO) Protocol that generalizes the concept of Traffic Optimization (ALTO) Protocol that generalizes the concept of
"endpoint properties", which have been tied to IP addresses so far, "endpoint properties", which have been tied to IP addresses so far,
to entities defined by a wide set of objects. Further, these to entities defined by a wide set of objects. Further, these
properties are presented as maps, similar to the network and cost properties are presented as maps, similar to the network and cost
maps in the base ALTO Protocol. While supporting the endpoints and maps in the base ALTO Protocol. While supporting the endpoints and
related Endpoint Property Service defined in RFC 7285, the ALTO related Endpoint Property Service defined in RFC 7285, the ALTO
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The ALTO Protocol [RFC7285] introduces the concept of "properties" The ALTO Protocol [RFC7285] introduces the concept of "properties"
attached to "endpoint addresses". It also defines the Endpoint attached to "endpoint addresses". It also defines the Endpoint
Property Service (EPS) to allow ALTO clients to retrieve those Property Service (EPS) to allow ALTO clients to retrieve those
properties. While useful, the EPS as defined in [RFC7285] has at properties. While useful, the EPS as defined in [RFC7285] has at
least three limitations, which are elaborated here. least three limitations, which are elaborated here.
First, the EPS allows properties to be associated only with endpoints First, the EPS allows properties to be associated only with endpoints
that are identified by individual communication addresses like IPv4 that are identified by individual communication addresses like IPv4
and IPv6 addresses. It is reasonable to think that collections of and IPv6 addresses. It is reasonable to think that collections of
endpoints or Provider-Defined Identifiers (PIDs), may also have endpoints identified by Provider-Defined Identifiers (PIDs) may also
properties. Furthermore, recent ALTO use cases show that properties have properties. Furthermore, recent ALTO use cases show that
of entities such as Abstract Network Elements as defined in properties of entities such as Abstract Network Elements as defined
[PATH-VECTOR] are also useful. However, the current EPS is in [PATH-VECTOR] are also useful. However, the current EPS is
restricted to individual endpoints and cannot be applied to those restricted to individual endpoints and cannot be applied to those
entities. entities.
Second, the EPS only allows endpoints identified by global Second, the EPS only allows endpoints identified by global
communication addresses. However, an endpoint address may be a local communication addresses. However, an endpoint address may be a local
IP address or an anycast IP address that may not be globally unique. IP address or an anycast IP address that may not be globally unique.
Additionally, an entity such as a PID may have an identifier that is Additionally, an entity such as a PID may have an identifier that is
not globally unique. That is, the same PID may be used in multiple not globally unique. That is, the same PID may be used in multiple
network maps, while in each network map, this PID points to a network maps, while in each network map, this PID points to a
different set of addresses. different set of addresses.
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[RFC7285] defines a GET-mode cost map resource that returns all [RFC7285] defines a GET-mode cost map resource that returns all
available costs, so an ALTO Client can retrieve a full set of costs available costs, so an ALTO Client can retrieve a full set of costs
once and then process cost lookups without querying the ALTO server. once and then process cost lookups without querying the ALTO server.
[RFC7285] does not define a similar service for endpoint properties. [RFC7285] does not define a similar service for endpoint properties.
At first, a map of endpoint properties might seem impractical because At first, a map of endpoint properties might seem impractical because
it could require enumerating the property value for every possible it could require enumerating the property value for every possible
endpoint. In particular, the number of endpoint addresses involved endpoint. In particular, the number of endpoint addresses involved
by an ALTO server can be quite large. To avoid enumerating a large by an ALTO server can be quite large. To avoid enumerating a large
number of endpoint addresses inefficiently, the ALTO server might number of endpoint addresses inefficiently, the ALTO server might
define properties for a sufficiently large subset of endpoints and define properties for a sufficiently large subset of endpoints and
uses an aggregation representation to reference endpoints to allow then use an aggregation representation to reference endpoints in
efficient enumeration. This is particularly true if blocks of order to allow efficient enumeration. This is particularly true if
endpoint addresses with a common prefix have the same value for a blocks of endpoint addresses with a common prefix have the same value
property. Entities in other domains may very well allow aggregated for a property. Entities in other domains may very well allow
representation and hence be enumerable as well. aggregated representation and hence be enumerable as well.
To address these three limitations, this document specifies an ALTO To address these three limitations, this document specifies an ALTO
Protocol extension for defining and retrieving ALTO properties: Protocol extension for defining and retrieving ALTO properties:
* The first limitation is addressed by introducing a generic concept * The first limitation is addressed by introducing a generic concept
called ALTO Entity, which generalizes an endpoint and may called ALTO entity, which generalizes an endpoint and may
represent a PID, a network element, a cell in a cellular network, represent a PID, a network element, a cell in a cellular network,
an Abstract Network Element [PATH-VECTOR], or other physical or an Abstract Network Element [PATH-VECTOR], or other physical or
logical objects involved in a network topology. Each entity is logical objects involved in a network topology. Each entity is
included in a collection called an ALTO entity domain. Since each included in a collection called an ALTO entity domain. Since each
ALTO entity domain includes only one type of entity, each entity ALTO entity domain includes only one type of entity, each entity
domain can be classified by the type of enclosed entities. domain can be classified by the type of enclosed entities.
* The second limitation is addressed by using resource-specific * The second limitation is addressed by using resource-specific
entity domains. A resource-specific entity domain contains entity domains. A resource-specific entity domain contains
entities that are defined and identified with respect to a given entities that are defined and identified with respect to a given
ALTO information resource, which provides scoping. For example, ALTO information resource, which provides scoping. For example,
an entity domain containing PIDs is identified with respect to the an entity domain containing PIDs is identified with respect to the
network map in which these PIDs are defined. Likewise, an entity network map in which these PIDs are defined. Likewise, an entity
domain containing local IP addresses may be defined with respect domain containing local IP addresses may be defined with respect
to a local network map. to a local network map.
* The third limitation is addressed by defining two new types of * The third limitation is addressed by defining two new types of
ALTO information resources: Property Map (Section 7) and Filtered ALTO information resources: property map (Section 7) and filtered
Property Map (Section 8). The former is a resource that is property map (Section 8). The former is a resource that is
requested using the HTTP GET method, returns the property values requested using the HTTP GET method, returns the property values
for all entities in one or more entity domains, and is analogous for all entities in one or more entity domains, and is analogous
to a network map or a cost map in Section 11.2 of [RFC7285]. The to a network map or a cost map in Section 11.2 of [RFC7285]. The
latter is a resource that is requested using the HTTP POST method, latter is a resource that is requested using the HTTP POST method,
returns the values for sets of properties and entities requested returns the values for sets of properties and entities requested
by the client, and is analogous to a filtered network map or a by the client, and is analogous to a filtered network map or a
filtered cost map. filtered cost map.
The Entity Property Maps extension described in this document The entity property maps extension described in this document
introduces a number of features that are summarized in Appendix A, introduces a number of features that are summarized in Appendix A,
where Table 4 lists the features and references the sections in this where Table 11 lists the features and references the sections in this
document that give their high-level and their normative descriptions. document that give their high-level and their normative descriptions.
The protocol extension defined in this document can be augmented. The protocol extension defined in this document can be augmented.
New entity domain types can be defined without revising the present New entity domain types can be defined without revising the present
specification. Similarly, new cost metrics and new endpoint specification. Similarly, new cost metrics and new endpoint
properties can be defined in other documents without revising the properties can be defined in other documents without revising the
protocol specification defined in [RFC7285]. protocol specification defined in [RFC7285].
1.1. Terminology and Notation 1.1. Terminology and Notation
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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 "OPTIONAL" in this document are to be interpreted as described in
BCP 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.
3. Basic Features of the Entity Property Map Extension 3. Basic Features of the Entity Property Map Extension
This section gives a high-level overview of the basic features This section gives a high-level overview of the basic features
involved in ALTO Entity Property Maps. It assumes the reader is involved in ALTO entity property maps. It assumes the reader is
familiar with the ALTO Protocol [RFC7285]. The purpose of this familiar with the ALTO Protocol [RFC7285]. The purpose of this
extension is to convey properties for objects that extend ALTO extension is to convey properties for objects that extend ALTO
endpoints and are called ALTO Entities, or entities for short. endpoints and are called ALTO Entities, or entities for short.
The features introduced in this section can be used standalone. The features introduced in this section can be used standalone.
However, in some cases, these features may depend on particular However, in some cases, these features may depend on particular
information resources and need to be defined with respect to them. information resources and need to be defined with respect to them.
To this end, Section 4 introduces additional features that extend the To this end, Section 4 introduces additional features that extend the
ones presented in this section. ones presented in this section.
3.1. Entity 3.1. Entity
The concept of an ALTO Entity generalizes the concept of an ALTO The concept of an ALTO entity generalizes the concept of an ALTO
endpoint defined in Section 2.1 of [RFC7285]. An entity is an object endpoint defined in Section 2.1 of [RFC7285]. An entity is an object
that can be an endpoint defined by its network address, but it can that can be an endpoint defined by its network address, but it can
also be an object that has a defined mapping to a set of one or more also be an object that has a defined mapping to a set of one or more
network addresses or an object that is not even related to any network addresses or an object that is not even related to any
network address. Thus, whereas all endpoints are entities, not all network address. Thus, whereas all endpoints are entities, not all
entities are endpoints. entities are endpoints.
Examples of entities are: Examples of entities are:
* an ALTO endpoint that represents an application or a host * an ALTO endpoint that represents an application or a host
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* an Autonomous System (AS) that has an AS number (ASN) as its * an Autonomous System (AS) that has an AS number (ASN) as its
identifier and maps to a set of IPv4 and IPv6 addresses, which is identifier and maps to a set of IPv4 and IPv6 addresses, which is
defined in [RFC9241], defined in [RFC9241],
* a country with a code specified in [ISO3166-1] to which * a country with a code specified in [ISO3166-1] to which
applications such as content delivery network (CDN) providers applications such as content delivery network (CDN) providers
associate properties and capabilities, which is defined in associate properties and capabilities, which is defined in
[RFC9241], [RFC9241],
* a TCP/UDP network flow that is identified by a TCP/UDP 5-tuple * a TCP or UDP network flow that is identified by a 5-tuple
specifying its source and destination addresses and port numbers, specifying its source and destination addresses and port numbers,
and the IP protocol, and the IP protocol (TCP or UDP),
* a routing element, as specified in [RFC7921], that is associated * a routing element, as specified in [RFC7921], that is associated
with routing capabilities information, or with routing capabilities information, or
* an Abstract Network Element, as specified in [PATH-VECTOR], that * an Abstract Network Element, as specified in [PATH-VECTOR], that
represents an abstraction of a network part such as a router, one represents an abstraction of a network part such as a router, one
or more links, a network domain, or their aggregation. or more links, a network domain, or their aggregation.
Some of the example entities listed above have already been Some of the example entities listed above have already been
documented as ALTO entities. The other examples are provided for documented as ALTO entities. The other examples are provided for
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In this document, an entity is owned by exactly one entity domain In this document, an entity is owned by exactly one entity domain
name. An entity identifier points to exactly one entity. If two name. An entity identifier points to exactly one entity. If two
entities in two different entity domains refer to the same physical entities in two different entity domains refer to the same physical
or logical object, they are treated as different entities. For or logical object, they are treated as different entities. For
example, if an end host has both an IPv4 and an IPv6 address, these example, if an end host has both an IPv4 and an IPv6 address, these
two addresses will be treated as two entities, defined respectively two addresses will be treated as two entities, defined respectively
in the "ipv4" and "ipv6" entity domains. in the "ipv4" and "ipv6" entity domains.
3.2.1. Entity Domain Type 3.2.1. Entity Domain Type
The type of an entity domain type defines the semantics of a type of The entity domain type defines the semantics of the type of entity
entity. Entity domain types can be defined in different documents. found in an entity domain. Entity domain types can be defined in
For example: the present document defines entity domain types "ipv4" different documents. For example: the present document defines
and "ipv6" in Section 6.1 and "pid" in Section 6.2. The entity entity domain types "ipv4" and "ipv6" in Section 6.1 and "pid" in
domain type "ane", which defines Abstract Network Elements (ANEs), is Section 6.2. The entity domain type "ane", which defines Abstract
introduced in [PATH-VECTOR]. The entity domain type that defines Network Elements (ANEs), is introduced in [PATH-VECTOR]. The
country codes is introduced in [RFC9241]. An entity domain type MUST "countrycode" entity domain type that defines country codes is
be registered with IANA, as specified in Section 12.3.2. introduced in [RFC9241]. An entity domain type MUST be registered
with IANA, as specified in Section 12.3.2.
3.2.2. Entity Domain Name 3.2.2. Entity Domain Name
In this document, the identifier of an entity domain is mostly called In this document, the identifier of an entity domain is mostly called
"entity domain name". The identifier of an entity domain is defined "entity domain name". The identifier of an entity domain is scoped
in the scope of an ALTO server. An entity domain identifier can to an ALTO server. An entity domain identifier can sometimes be
sometimes be identical to the identifier of its relevant entity identical to the identifier of its relevant entity domain type. This
domain type. This is the case when the entities of a domain have an is the case when the entities of a domain have an identifier that
identifier that points to the same object throughout all the points to the same object throughout all the information resources of
information resources of the Server that provide entity properties the Server that are providing entity properties for this domain. For
for this domain. For example, a domain of type "ipv4" containing example, a domain of type "ipv4" containing entities that are
entities that are identified by a public IPv4 address can be named identified by a public IPv4 address can be named "ipv4" because its
"ipv4" because its entities are uniquely identified by all the Server entities are uniquely identified by all the Server resources.
resources.
In some cases, the name of an entity domain cannot be simply its In some cases, the name of an entity domain cannot be simply its
entity domain type. Indeed, for some domain types, entities are entity domain type. Indeed, for some domain types, entities are
defined relative to a given information resource. This is the case defined relative to a given information resource. This is the case
for entities of domain type "pid". A PID is defined relative to a for entities of domain type "pid". A PID is defined relative to a
network map. For example, an entity "mypid10" of domain type "pid" network map. For example, an entity "mypid10" of domain type "pid"
may be defined in a given network map and be undefined in other may be defined in a given network map and be undefined in other
network maps. The entity "mypid10" may even be defined in two network maps. The entity "mypid10" may even be defined in two
different network maps, and it may map in each of these network maps different network maps, and it may map in each of these network maps
to a different set of endpoint addresses. In this case, naming an to a different set of endpoint addresses. In this case, naming an
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Likewise, the same identifier may point to both a domain name and a Likewise, the same identifier may point to both a domain name and a
property name. For example: the identifier "netmap10.pid" may point property name. For example: the identifier "netmap10.pid" may point
to either the domain defined by the PIDs of network map "netmap10" or to either the domain defined by the PIDs of network map "netmap10" or
to a property that returns, for an entity defined by its IPv4 to a property that returns, for an entity defined by its IPv4
address, the PID of "netmap10" that contains this entity. Such cases address, the PID of "netmap10" that contains this entity. Such cases
are further explained in Section 4. are further explained in Section 4.
3.4. New Information Resource and Media Type: ALTO Property Map 3.4. New Information Resource and Media Type: ALTO Property Map
This document introduces a new ALTO information resource named This document introduces a new ALTO information resource named
Property Map. An ALTO property map provides a set of properties for property map. An ALTO property map provides a set of properties for
one or more sets of entities. A property may apply to different one or more sets of entities. A property may apply to different
entity domain types and names. For example, an ALTO property map may entity domain types and names. For example, an ALTO property map may
define the "ASN" property for both "ipv4" and "ipv6" entity domains. define the "ASN" property for both "ipv4" and "ipv6" entity domains.
The present extension also introduces a new media type. The present extension also introduces a new media type.
This document uses the same definition of an information resource as This document uses the same definition of an information resource as
Section 9.1 of [RFC7285]. ALTO uses media types to uniquely indicate Section 9.1 of [RFC7285]. ALTO uses media types to uniquely indicate
the data format used to encode the content to be transmitted between the data format used to encode the content to be transmitted between
an ALTO server and an ALTO client in the HTTP entity body. In the an ALTO server and an ALTO client in the HTTP entity body. In the
present case, an ALTO property map resource is defined by the media present case, an ALTO property map resource is defined by the media
type "application/alto-propmap+json". type "application/alto-propmap+json".
A Property Map can be queried as a GET-mode resource, thus conveying A property map can be queried as a GET-mode resource, thus conveying
all properties for all entities indicated in its capabilities. It all properties for all entities indicated in its capabilities. It
can also be queried as a POST-mode resource, thus conveying a can also be queried as a POST-mode resource, thus conveying a
selection of properties for a selection of entities. selection of properties for a selection of entities.
4. Advanced Features of the Entity Property Map Extension 4. Advanced Features of the Entity Property Map Extension
This section gives a high-level overview of the advanced features This section gives a high-level overview of the advanced features
involved in ALTO Entity Property Maps. Most of these features extend involved in ALTO entity property maps. Most of these features extend
the features defined in Section 3. the features defined in Section 3.
4.1. Entity Identifier and Entity Domain Name 4.1. Entity Identifier and Entity Domain Name
In [RFC7285], an endpoint has an identifier that is explicitly In [RFC7285], an endpoint has an identifier that is explicitly
associated with the "ipv4" or "ipv6" address domain. Examples are associated with the "ipv4" or "ipv6" address domain. Examples are
"ipv4:192.0.2.14" and "ipv6:2001:db8::12". "ipv4:192.0.2.14" and "ipv6:2001:db8::12".
In this document, example IPv4 and IPv6 addresses and prefixes are In this document, example IPv4 and IPv6 addresses and prefixes are
taken from the address ranges reserved for documentation by [RFC5737] taken from the address ranges reserved for documentation by [RFC5737]
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Additionally, entity sets sometimes are related by inclusion, Additionally, entity sets sometimes are related by inclusion,
hierarchy, or other relations. This allows defining inheritance hierarchy, or other relations. This allows defining inheritance
rules for entity properties that propagate properties among related rules for entity properties that propagate properties among related
entity sets. The Server and the Client can use these inheritance entity sets. The Server and the Client can use these inheritance
rules for further payload savings. Entity hierarchy and property rules for further payload savings. Entity hierarchy and property
inheritance rules are specified in the documents that define the inheritance rules are specified in the documents that define the
applicable domain types. The present document defines these rules applicable domain types. The present document defines these rules
for the "ipv4" and "ipv6" domain types. for the "ipv4" and "ipv6" domain types.
For applicable domain types, this document introduces "Entity For applicable domain types, this document introduces entity property
Property Inheritance rules" with the following concepts: Entity inheritance rules with the following concepts: entity hierarchy,
Hierarchy, Property Inheritance, and Property Value Unicity. A property inheritance, and property value unicity. A detailed
detailed specification of entity hierarchy and property inheritance specification of entity hierarchy and property inheritance rules is
rules is provided in Section 5.1.4. provided in Section 5.1.4.
4.4.1. Entity Hierarchy 4.4.1. Entity Hierarchy
An entity domain may allow the use of a single identifier to identify An entity domain may allow the use of a single identifier to identify
a set of related individual entities. For example, a Classless a set of related individual entities. For example, a Classless
Inter-Domain Routing (CIDR) block can be used to identify a set of Inter-Domain Routing (CIDR) block can be used to identify a set of
IPv4 or IPv6 entities. A CIDR block is called a hierarchical entity IPv4 or IPv6 entities. A CIDR block is called a hierarchical entity
identifier, as it can reflect inclusion relations among entity sets. identifier, as it can reflect inclusion relations among entity sets.
That is, in an entity hierarchy, "supersets" are defined at upper That is, in an entity hierarchy, "supersets" are defined at upper
levels and include "subsets" defined at lower levels. For example, levels and include "subsets" defined at lower levels. For example,
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an entity. An example illustrating the need for such rules is an entity. An example illustrating the need for such rules is
provided in Section 6.1.3. provided in Section 6.1.3.
4.5. Supported Properties for Entity Domains in Property Map 4.5. Supported Properties for Entity Domains in Property Map
Capabilities Capabilities
A property type is not necessarily applicable to any domain type, or A property type is not necessarily applicable to any domain type, or
an ALTO Server may choose not to provide a property for all an ALTO Server may choose not to provide a property for all
applicable domains. For instance, a property type reflecting link applicable domains. For instance, a property type reflecting link
bandwidth is likely not defined for entities of a domain of type bandwidth is likely not defined for entities of a domain of type
"countrycode". Therefore, an ALTO server providing Property Maps "countrycode". Therefore, an ALTO server providing property maps
needs to specify the properties that can be queried on the different needs to specify the properties that can be queried on the different
entity domains it supports. entity domains it supports.
This document explains how the Information Resource Directory (IRD) This document explains how the Information Resource Directory (IRD)
capabilities of a Property Map resource unambiguously expose which capabilities of a property map resource unambiguously expose which
properties a Client can query on a given entity domain: properties a Client can query on a given entity domain:
* a field named "mappings" lists the names of the entity domains * a field named "mappings" lists the names of the entity domains
supported by the Property Map, and supported by the property map, and
* for each listed entity domain, a list of the names of the * for each listed entity domain, a list of the names of the
applicable properties is provided. applicable properties is provided.
An example is provided in Section 10.3. The "mappings" field An example is provided in Section 10.3. The "mappings" field
associates entity domains and properties that can be resource- associates entity domains and properties that can be resource-
agnostic or resource-specific. This allows a Client to formulate agnostic or resource-specific. This allows a Client to formulate
compact and unambiguous entity property queries, possibly relating to compact and unambiguous entity property queries, possibly relating to
one or more information resources. In particular: one or more information resources. In particular:
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following reason: although a cost map exposes PID identifiers, it following reason: although a cost map exposes PID identifiers, it
does not define the set of addresses included in this PID. Neither does not define the set of addresses included in this PID. Neither
does a cost map list all the PIDs on which properties can be queried does a cost map list all the PIDs on which properties can be queried
because a cost map only exposes PID pairs on which a queried cost because a cost map only exposes PID pairs on which a queried cost
type is defined. Therefore, the resource "costmap3" does not enable type is defined. Therefore, the resource "costmap3" does not enable
a Client to extract information on the existing PID entities or on a Client to extract information on the existing PID entities or on
the addresses they contain. the addresses they contain.
Instead, the cost map uses a network map where all the PIDs used in a Instead, the cost map uses a network map where all the PIDs used in a
cost map are defined together with the addresses contained by the cost map are defined together with the addresses contained by the
PIDs. This network map is qualified in this document as the Defining PIDs. This network map is qualified in this document as the defining
Information Resource for the entity domain of type "pid", and this information resource for the entity domain of type "pid", and this
concept is explained in Section 4.6.1. concept is explained in Section 4.6.1.
4.6.1. Defining Information Resource and Its Media Type 4.6.1. Defining Information Resource and Its Media Type
For the reasons explained in Section 4.6, this document introduces For the reasons explained in Section 4.6, this document introduces
the concept of "Defining Information Resource and its Media Type". the concept of "Defining Information Resource and its Media Type".
A defining information resource for an entity domain D is the A defining information resource for an entity domain D is the
information resource where entities of D are defined. That is, all information resource where entities of D are defined. That is, all
the information on the entities of D can be retrieved in this the information on the entities of D can be retrieved in this
resource. A defining information resource is defined for resource- resource. A defining information resource is defined for resource-
specific entity domains. It does not exist for entity domains that specific entity domains. It does not exist for entity domains that
are not resource-specific such as "ipv4" or "ipv6". Neither does it are not resource-specific such as "ipv4" or "ipv6". Neither does it
exist for entity domains that are covering entity identifiers already exist for entity domains that are covering entity identifiers already
defined in other standardization documents, as is the case for defined in other standardization documents, as is the case for
country code identifiers standardized in [ISO3166-1] or AS numbers country code identifiers standardized in [ISO3166-1] or AS numbers
allocated by IANA. This is useful for entity domain types that are allocated by IANA. This is useful for entity domain types that are
by essence domain-specific, such as the "pid" domain type. It is by essence domain-specific, such as the domain type "pid". It is
also useful for resource-specific entity domains constructed from also useful for resource-specific entity domains constructed from
resource-agnostic domain types, such as network-map-specific domains resource-agnostic domain types, such as network-map-specific domains
of local IPv4 addresses. of local IPv4 addresses.
The defining information resource of a resource-specific entity The defining information resource of a resource-specific entity
domain D, when it exists, is unique and has the following domain D, when it exists, is unique and has the following
characteristics: characteristics:
* it has an entry in the IRD; * it has an entry in the IRD;
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A fundamental characteristic of a defining information resource is A fundamental characteristic of a defining information resource is
its media type. There is a unique association between an entity its media type. There is a unique association between an entity
domain type and the media type of its defining information resource. domain type and the media type of its defining information resource.
When an entity domain type allows associations with defining When an entity domain type allows associations with defining
information resources, the media type of the potential defining information resources, the media type of the potential defining
information resource MUST be specified: information resource MUST be specified:
* in the document that defines this entity domain type, and * in the document that defines this entity domain type, and
* in the "ALTO Entity Domain Types" IANA registry and related * in the "ALTO Entity Domain Types" IANA registry.
information.
When the Client wants to use a resource-specific entity domain, it When the Client wants to use a resource-specific entity domain, it
needs to be cognizant of the media type of its defining information needs to be cognizant of the media type of its defining information
resource. If the Server exposes a resource-specific entity domain resource. If the Server exposes a resource-specific entity domain
with a noncompliant media type for the defining resource, the Client with a noncompliant media type for the defining resource, the Client
MUST ignore the entities from that entity domain to avoid errors. MUST ignore the entities from that entity domain to avoid errors.
4.6.2. Examples of Defining Information Resources and Their Media Types 4.6.2. Examples of Defining Information Resources and Their Media Types
Here are examples of defining information resource types and their Here are examples of defining information resource types and their
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specific resource is "application/alto-networkmap+json" because specific resource is "application/alto-networkmap+json" because
IPv4 and IPv6 addresses covered by the Server are defined in IPv4 and IPv6 addresses covered by the Server are defined in
network map resources. network map resources.
* For entities of domain type "ane"; [PATH-VECTOR] defines entities * For entities of domain type "ane"; [PATH-VECTOR] defines entities
named "ANE", where ANE stands for Abstract Network Element, and named "ANE", where ANE stands for Abstract Network Element, and
the entity domain type "ane". An ANE may have a persistent the entity domain type "ane". An ANE may have a persistent
identifier, say, "entity-4", that is provided by the Server as a identifier, say, "entity-4", that is provided by the Server as a
value of the "persistent-entity-id" property of this ANE. Further value of the "persistent-entity-id" property of this ANE. Further
properties may then be queried on an ANE by using its persistent properties may then be queried on an ANE by using its persistent
entity ID. These properties are available from a persistent entity identifier. These properties are available from a
property map that defines properties for a specific "ane" domain. persistent property map that defines properties for a specific
Together with the persistent identifier, the Server also provides "ane" domain. Together with the persistent identifier, the Server
the property map resource identifier where the "ane" domain also provides the property map resource identifier where the "ane"
containing "entity-4" is defined. The definition of the "ane" domain containing "entity-4" is defined. The definition of the
entity domain containing "entity-4" is thus specific to the "ane" entity domain containing "entity-4" is thus specific to the
property map. Therefore, for entities of domain type "ane" that property map. Therefore, for entities of domain type "ane" that
have a persistent identifier, the media type of the defining have a persistent identifier, the media type of the defining
information resource is "application/alto-propmap+json". information resource is "application/alto-propmap+json".
* Last, the entity domain types "asn" and "countrycode" defined in * Last, the entity domain types "asn" and "countrycode" defined in
[RFC9241] do not have a defining information resource. Indeed, [RFC9241] do not have a defining information resource. Indeed,
the entity identifiers in these two entity domain types are the entity identifiers in these two entity domain types are
already standardized in documents that the Client can use. already standardized in documents that the Client can use.
4.7. Defining Information Resources for Resource-Specific Property 4.7. Defining Information Resources for Resource-Specific Property
skipping to change at line 873 skipping to change at line 873
5. Protocol Specification: Basic Data Types 5. Protocol Specification: Basic Data Types
5.1. Entity Domain 5.1. Entity Domain
5.1.1. Entity Domain Type 5.1.1. Entity Domain Type
An entity domain has a type, which is uniquely identified by a string An entity domain has a type, which is uniquely identified by a string
that MUST be no more than 64 characters, and MUST NOT contain that MUST be no more than 64 characters, and MUST NOT contain
characters other than US-ASCII alphanumeric characters characters other than US-ASCII alphanumeric characters
(U+0030-U+0039, U+0041-U+005A, and U+0061-U+007A), the hyphen ('-', (U+0030-U+0039, U+0041-U+005A, and U+0061-U+007A), the hyphen-minus
U+002D), the colon (':', U+003A), or the low line ('_', U+005F). ('-', U+002D), the colon (':', U+003A), or the low line ('_',
U+005F).
The usage of colon (':', U+003A) MUST obey the rules below: The usage of colon (':', U+003A) MUST obey the rules below:
* The colon (':', U+003A) character MUST NOT appear more than once; * The colon (':', U+003A) character MUST NOT appear more than once;
* The colon character MUST NOT be used unless within the string * The colon character MUST NOT be used unless within the string
"priv:"; "priv:";
* The string "priv:" MUST NOT be used unless it starts the string * The string "priv:" MUST NOT be used unless it starts the string
that identifies an entity domain type; and that identifies an entity domain type; and
skipping to change at line 944 skipping to change at line 945
"[ [ ResourceID ] '.' ]" "[ [ ResourceID ] '.' ]"
depends on the category of entity domain. depends on the category of entity domain.
Note that the '.' separator is not allowed in EntityDomainType, and Note that the '.' separator is not allowed in EntityDomainType, and
hence there is no ambiguity on whether an entity domain name refers hence there is no ambiguity on whether an entity domain name refers
to a resource-agnostic entity domain or a resource-specific entity to a resource-agnostic entity domain or a resource-specific entity
domain. domain.
Note also that Section 10.1 of [RFC7285] specifies the format of the Note also that Section 10.1 of [RFC7285] specifies the format of the
PID name, which is the format of the resource ID including the PID name, which is the format of the resource identifier including
following specification: the following specification:
| The '.' separator is reserved for future use and MUST NOT be used | The '.' separator is reserved for future use and MUST NOT be used
| unless specifically indicated in this document, or an extension | unless specifically indicated in this document, or an extension
| document. | document.
The present extension keeps the format specification of [RFC7285], The present extension keeps the format specification of [RFC7285],
hence the '.' separator MUST NOT be used in an information resource hence the '.' separator MUST NOT be used in an information resource
ID. identifier.
5.1.2.1. Resource-Specific Entity Domain 5.1.2.1. Resource-Specific Entity Domain
A resource-specific entity domain is identified by an entity domain A resource-specific entity domain is identified by an entity domain
name constructed as follows. It MUST start with a resource ID using name constructed as follows. It MUST start with a resource
the ResourceID type defined in Section 10.2 of [RFC7285], followed by identifier using the ResourceID type defined in Section 10.2 of
the '.' separator (U+002E), followed by a string of the type [RFC7285], followed by the '.' separator (U+002E), followed by a
EntityDomainType specified in Section 5.1.1. string of the type EntityDomainType specified in Section 5.1.1.
For example, if an ALTO server provides two network maps "netmap-1" For example, if an ALTO server provides two network maps "netmap-1"
and "netmap-2", these network maps can define two resource-specific and "netmap-2", these network maps can define two resource-specific
domains of type "pid", respectively identified by "netmap-1.pid" and domains of type "pid", respectively identified by "netmap-1.pid" and
"netmap-2.pid". "netmap-2.pid".
5.1.2.2. Resource-Agnostic Entity Domain 5.1.2.2. Resource-Agnostic Entity Domain
A resource-agnostic entity domain contains entities that are A resource-agnostic entity domain contains entities that are
identified independently of any information resource. The identifier identified independently of any information resource. The identifier
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identifier of a self-defined entity domain can be of the format: identifier of a self-defined entity domain can be of the format:
EntityDomainName ::= '.' EntityDomainType EntityDomainName ::= '.' EntityDomainType
where '.' indicates that the entity domain only exists within the where '.' indicates that the entity domain only exists within the
property map resource using it. property map resource using it.
A self-defined entity domain can be viewed as a particular case of A self-defined entity domain can be viewed as a particular case of
resource-specific entity domain, where the specific resource is the resource-specific entity domain, where the specific resource is the
current resource that uses this entity domain. In that case, for the current resource that uses this entity domain. In that case, for the
sake of simplification, the component "ResourceID" MUST be omitted in sake of simplification, the component ResourceID MUST be omitted in
its entity domain name. its entity domain name.
5.1.3. Entity Identifier 5.1.3. Entity Identifier
Entities in an entity domain are identified by entity identifiers Entities in an entity domain are identified by entity identifiers
(EntityID) of the following format: (EntityID) of the following format:
EntityID ::= EntityDomainName ':' DomainTypeSpecificEntityID EntityID ::= EntityDomainName ':' DomainTypeSpecificEntityID
Examples from the Internet address entity domains include individual Examples from the Internet address entity domains include individual
skipping to change at line 1059 skipping to change at line 1060
Each entity property has a type to indicate the encoding and the Each entity property has a type to indicate the encoding and the
semantics of the value of this entity property, and has a name to semantics of the value of this entity property, and has a name to
identify it. identify it.
5.2.1. Entity Property Type 5.2.1. Entity Property Type
The type EntityPropertyType is used in this document to indicate a The type EntityPropertyType is used in this document to indicate a
string denoting an entity property type. The string MUST be no more string denoting an entity property type. The string MUST be no more
than 32 characters, and it MUST NOT contain characters other than US- than 32 characters, and it MUST NOT contain characters other than US-
ASCII alphanumeric characters (U+0030-U+0039, U+0041-U+005A, and ASCII alphanumeric characters (U+0030-U+0039, U+0041-U+005A, and
U+0061-U+007A), the hyphen ('-', U+002D), the colon (':', U+003A), or U+0061-U+007A), the hyphen-minus ('-', U+002D), the colon (':',
the low line ('_', U+005F). Note that the '.' separator is not U+003A), or the low line ('_', U+005F). Note that the '.' separator
allowed because it is reserved to separate an entity property type is not allowed because it is reserved to separate an entity property
and an information resource identifier when an entity property is type and an information resource identifier when an entity property
resource-specific. is resource-specific.
While Section 5.1.1 allows the use of the character ":" with While Section 5.1.1 allows the use of the character ":" with
restrictions on entity domain identifiers, it can be used without restrictions on entity domain identifiers, it can be used without
restrictions on entity property type identifiers. This relates to restrictions on entity property type identifiers. This relates to
[RFC7285], where a Server can define properties for endpoints "ipv4" [RFC7285], where a Server can define properties for endpoints "ipv4"
and "ipv6". In the present extension, there is a mapping of ALTO and "ipv6". In the present extension, there is a mapping of ALTO
entity domain types "ipv4" and "ipv6" to ALTO address types "ipv4" entity domain types "ipv4" and "ipv6" to ALTO address types "ipv4"
and "ipv6". Properties defined for "ipv4" and "ipv6" endpoints and "ipv6". Properties defined for "ipv4" and "ipv6" endpoints
should be reusable on "ipv4" and "ipv6" entities. Forbidding the should be reusable on "ipv4" and "ipv6" entities. Forbidding the
usage of ":" in a non-private entity property type identifier would usage of ":" in a non-private entity property type identifier would
skipping to change at line 1111 skipping to change at line 1112
or "ipv6", while it is not applicable to entities in an entity or "ipv6", while it is not applicable to entities in an entity
domain of type "pid". domain of type "pid".
* The intended semantics of the value of an entity property may also * The intended semantics of the value of an entity property may also
depend on the entity domain type. For example, suppose that a depend on the entity domain type. For example, suppose that a
property named "geo-location" is defined as the coordinates of a property named "geo-location" is defined as the coordinates of a
point and is encoded as: "latitude longitude [altitude]." When point and is encoded as: "latitude longitude [altitude]." When
applied to an entity that represents a specific host computer and applied to an entity that represents a specific host computer and
identified by an address in an entity domain of type "ipv4" or identified by an address in an entity domain of type "ipv4" or
"ipv6", the "geo-location" property would define the host's "ipv6", the "geo-location" property would define the host's
location. However, when applied to an entity in a "pid" domain location. However, when applied to an entity in a domain of type
type, the property would indicate a location representative of all "pid", the property would indicate a location representative of
hosts in this "pid" entity. all hosts in this "pid" entity.
5.2.2. Entity Property Name 5.2.2. Entity Property Name
Each entity property is identified by an entity property name, which Each entity property is identified by an entity property name, which
is a string of the following format: is a string of the following format:
EntityPropertyName ::= [ [ ResourceID ] '.' ] EntityPropertyType EntityPropertyName ::= [ [ ResourceID ] '.' ] EntityPropertyType
Similar to the endpoint property type defined in Section 10.8 of Similar to the endpoint property type defined in Section 10.8 of
[RFC7285], each entity property may be defined by either the property [RFC7285], each entity property may be defined by either the property
skipping to change at line 1137 skipping to change at line 1138
The entity property name of a resource-specific entity property The entity property name of a resource-specific entity property
starts with a string of the type ResourceID defined in [RFC7285], starts with a string of the type ResourceID defined in [RFC7285],
followed by the '.' separator (U+002E) and an EntityDomainType typed followed by the '.' separator (U+002E) and an EntityDomainType typed
string. For example, the "pid" properties of an "ipv4" entity string. For example, the "pid" properties of an "ipv4" entity
defined by two different maps "net-map-1" and "net-map-2" are defined by two different maps "net-map-1" and "net-map-2" are
identified by "net-map-1.pid" and "net-map-2.pid" respectively. identified by "net-map-1.pid" and "net-map-2.pid" respectively.
The specific information resource of an entity property may be the The specific information resource of an entity property may be the
current information resource itself, that is, the property map current information resource itself, that is, the property map
defining the property. In that case, the ResourceID in the property defining the property. In that case, the ResourceID in the property
name SHOULD be omitted. For example, the property name ".asn" name SHOULD be omitted. For example, the property name ".ASN"
applied to an entity identified by its IPv4 address indicates the AS applied to an entity identified by its IPv4 address indicates the AS
number of the AS that "owns" the entity, where the returned AS number number of the AS that "owns" the entity, where the returned AS number
is defined by the property map itself. is defined by the property map itself.
5.2.3. Format for Entity Property Value 5.2.3. Format for Entity Property Value
Section 11.4.1.6 of [RFC7285] specifies that an implementation of the Section 11.4.1.6 of [RFC7285] specifies that an implementation of the
Endpoint Property Service specified in [RFC7285] SHOULD assume that Endpoint Property Service specified in [RFC7285] SHOULD assume that
the property value is a JSONString and fail to parse if it is not. the property value is a JSONString and fail to parse if it is not.
This document extends the format of a property value by allowing it This document extends the format of a property value by allowing it
to be a JSONValue instead of just a JSONString. to be a JSONValue instead of just a JSONString.
6. Entity Domain Types Defined in This Document 6. Entity Domain Types Defined in This Document
The definition of each entity domain type MUST include (1) the entity The definition of each entity domain type MUST include the entity
domain type name and (2) domain-specific entity identifiers, and MAY domain type name and the domain-specific entity identifiers. The
include (3) hierarchy and inheritance semantics optionally. This definition of an entity domain type MAY include hierarchy and
document defines three initial entity domain types as follows. inheritance semantics. This document defines three initial entity
domain types as follows.
6.1. Internet Address Domain Types 6.1. Internet Address Domain Types
The document defines two entity domain types (IPv4 and IPv6) for The document defines two entity domain types (IPv4 and IPv6) for
Internet addresses. Both types are resource-agnostic entity domain Internet addresses. Both types are resource-agnostic entity domain
types and hence define corresponding resource-agnostic entity domains types and hence define corresponding resource-agnostic entity domains
as well. Since the two domains use the same hierarchy and as well. Since the two domains use the same hierarchy and
inheritance semantics, we define the semantics together, instead of inheritance semantics, we define the semantics together, instead of
repeating for each. repeating for each.
6.1.1. Entity Domain Type: IPv4 6.1.1. Entity Domain Type: IPv4
6.1.1.1. Entity Domain Type Identifier 6.1.1.1. Entity Domain Type Identifier
The identifier for this Entity Domain Type is "ipv4". The identifier for this entity domain type is "ipv4".
6.1.1.2. Domain-Specific Entity Identifiers 6.1.1.2. Domain-Specific Entity Identifiers
Individual addresses are strings as specified by the IPv4address rule Individual addresses are strings as specified by the IPv4address rule
in Section 3.2.2 of [RFC3986]; hierarchical addresses are strings as in Section 3.2.2 of [RFC3986]; hierarchical addresses are strings as
specified by the prefix notation in Section 3.1 of [RFC4632]. To specified by the prefix notation in Section 3.1 of [RFC4632]. An
define properties, an individual Internet address and the individual Internet address and the corresponding full-length prefix
corresponding full-length prefix are considered aliases for the same are considered aliases for the same entity on which to define
entity on which to define properties. Thus, "ipv4:192.0.2.0" and properties. Thus, "ipv4:192.0.2.0" and "ipv4:192.0.2.0/32" are
"ipv4:192.0.2.0/32" are equivalent. equivalent.
6.1.2. Entity Domain Type: IPv6 6.1.2. Entity Domain Type: IPv6
6.1.2.1. Entity Domain Type Identifier 6.1.2.1. Entity Domain Type Identifier
The identifier for this Entity Domain Type is "ipv6". The identifier for this Entity Domain Type is "ipv6".
6.1.2.2. Domain-Specific Entity Identifiers 6.1.2.2. Domain-Specific Entity Identifiers
Individual addresses are strings as specified by Section 4 of Individual addresses are strings as specified by Section 4 of
skipping to change at line 1210 skipping to change at line 1212
Both Internet address domains allow property values to be inherited. Both Internet address domains allow property values to be inherited.
Specifically, if a property P is not defined for a specific Internet Specifically, if a property P is not defined for a specific Internet
address I, but P is defined for a hierarchical Internet address C address I, but P is defined for a hierarchical Internet address C
that represents a set of addresses containing I, then the address I that represents a set of addresses containing I, then the address I
inherits the value of P defined for the hierarchical address C. If inherits the value of P defined for the hierarchical address C. If
more than one such hierarchical addresses define a value for P, I more than one such hierarchical addresses define a value for P, I
inherits the value of P in the hierarchical address with the longest inherits the value of P in the hierarchical address with the longest
prefix. Note that this longest prefix rule ensures no multiple value prefix. Note that this longest prefix rule ensures no multiple value
inheritances, and hence no ambiguity. inheritances, and hence no ambiguity.
Hierarchical addresses can also inherit properties: if a property P Hierarchical addresses can also inherit properties. For instance, if
is not defined for the hierarchical address C, but is defined for a a property P:
set of hierarchical addresses, where each address C' in the set
contains all IP addresses in C, and C' has a shorter prefix length * is not defined for the hierarchical address C,
than C, then C MUST inherit the property P from the C' having the
longest prefix length. * but is defined for a set of hierarchical addresses where:
- each address C' in the set contains all IP addresses in C, and
- C' has a shorter prefix length than C,
then C MUST inherit the property P from the C' having the longest
prefix length.
As an example, suppose that a server defines a property P for the As an example, suppose that a server defines a property P for the
following entities: following entities:
ipv4:192.0.2.0/26: P=v1 +--------------------+------+
ipv4:192.0.2.0/28: P=v2 | ipv4:192.0.2.0/26: | P=v1 |
ipv4:192.0.2.0/30: P=v3 +--------------------+------+
ipv4:192.0.2.0: P=v4 | ipv4:192.0.2.0/28: | P=v2 |
+--------------------+------+
| ipv4:192.0.2.0/30: | P=v3 |
+--------------------+------+
| ipv4:192.0.2.0: | P=v4 |
+--------------------+------+
Figure 1: Defined Property Values Table 1: Defined Property
Values
Then the following entities have the indicated values: Then the following entities have the indicated values:
ipv4:192.0.2.0: P=v4 +--------------------+---------------+
ipv4:192.0.2.1: P=v3 | ipv4:192.0.2.0: | P=v4 |
ipv4:192.0.2.16: P=v1 +--------------------+---------------+
ipv4:192.0.2.32: P=v1 | ipv4:192.0.2.1: | P=v3 |
ipv4:192.0.2.64: (not defined) +--------------------+---------------+
ipv4:192.0.2.0/32: P=v4 | ipv4:192.0.2.16: | P=v1 |
ipv4:192.0.2.0/31: P=v3 +--------------------+---------------+
ipv4:192.0.2.0/29: P=v2 | ipv4:192.0.2.32: | P=v1 |
ipv4:192.0.2.0/27: P=v1 +--------------------+---------------+
ipv4:192.0.2.0/25: (not defined) | ipv4:192.0.2.64: | (not defined) |
+--------------------+---------------+
| ipv4:192.0.2.0/32: | P=v4 |
+--------------------+---------------+
| ipv4:192.0.2.0/31: | P=v3 |
+--------------------+---------------+
| ipv4:192.0.2.0/29: | P=v2 |
+--------------------+---------------+
| ipv4:192.0.2.0/27: | P=v1 |
+--------------------+---------------+
| ipv4:192.0.2.0/25: | (not defined) |
+--------------------+---------------+
Figure 2: Inherited Property Values Table 2: Inherited Property Values
An ALTO server MAY explicitly indicate a property as not having a An ALTO server MAY explicitly indicate a property as not having a
value for a particular entity. That is, a server MAY say that value for a particular entity. That is, a server MAY say that
property P of entity X is "defined to have no value" instead of property P of entity X is "defined to have no value" instead of
"undefined". To indicate "no value", a server MAY perform different "undefined". To indicate "no value", a server MAY perform different
behaviors: behaviors:
* If entity X would inherit a value for property P, and if the ALTO * If entity X would inherit a value for property P, and if the ALTO
server decides to say that "X has no value for P", then the ALTO server decides to say that "X has no value for P", then the ALTO
server MUST return a "null" value for that property on X. In this server MUST return a "null" value for that property on X. In this
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If the ALTO server does not define any properties for an entity, then If the ALTO server does not define any properties for an entity, then
the server MAY omit that entity from the response. the server MAY omit that entity from the response.
6.1.4. Defining Information Resource Media Type for Domain Types IPv4 6.1.4. Defining Information Resource Media Type for Domain Types IPv4
and IPv6 and IPv6
Entity domain types "ipv4" and "ipv6" both allow the definition of Entity domain types "ipv4" and "ipv6" both allow the definition of
resource-specific entity domains. When resource-specific domains are resource-specific entity domains. When resource-specific domains are
defined with entities of domain type "ipv4" or "ipv6", the defining defined with entities of domain type "ipv4" or "ipv6", the defining
information resource for an entity domain of type "ipv4" or "ipv6" information resource for an entity domain of type "ipv4" or "ipv6"
MUST be a Network Map. The media type of a defining information MUST be a network map. The media type of a defining information
resource is therefore: resource is therefore:
application/alto-networkmap+json application/alto-networkmap+json
6.2. Entity Domain Type: PID 6.2. Entity Domain Type: PID
The PID entity domain associates property values with the PIDs in a The PID entity domain associates property values with the PIDs in a
network map. Accordingly, this entity domain always depends on a network map. Accordingly, this entity domain always depends on a
network map. network map.
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6.2.3. Hierarchy and Inheritance 6.2.3. Hierarchy and Inheritance
There is no hierarchy or inheritance for properties associated with There is no hierarchy or inheritance for properties associated with
PIDs. PIDs.
6.2.4. Defining Information Resource Media Type for Domain Type PID 6.2.4. Defining Information Resource Media Type for Domain Type PID
The entity domain type "pid" allows the definition of resource- The entity domain type "pid" allows the definition of resource-
specific entity domains. When resource-specific domains are defined specific entity domains. When resource-specific domains are defined
with entities of domain type "pid", the defining information resource with entities of domain type "pid", the defining information resource
for entity domain type "pid" MUST be a Network Map. The media type of for entity domain type "pid" MUST be a network map. The media type
a defining information resource is therefore: of a defining information resource is therefore:
application/alto-networkmap+json application/alto-networkmap+json
6.2.5. Relationship To Internet Addresses Domains 6.2.5. Relationship To Internet Addresses Domains
The PID domain and the Internet address domains are completely The PID domain and the Internet address domains are completely
independent; the properties associated with a PID have no relation to independent; the properties associated with a PID have no relation to
the properties associated with the prefixes or endpoint addresses in the properties associated with the prefixes or endpoint addresses in
that PID. An ALTO server MAY choose to assign all the properties of that PID. An ALTO server MAY choose to assign all the properties of
a PID to the prefixes in that PID or only some of these properties. a PID to the prefixes in that PID or only some of these properties.
skipping to change at line 1343 skipping to change at line 1369
For example, because Internet addresses are allocated to service For example, because Internet addresses are allocated to service
providers by blocks of prefixes, an "ISP" property would be best providers by blocks of prefixes, an "ISP" property would be best
associated with Internet address domain types. On the other hand, a associated with Internet address domain types. On the other hand, a
property that explains why a PID was formed, or how it relates to a property that explains why a PID was formed, or how it relates to a
provider's network, would best be associated with the PID domain provider's network, would best be associated with the PID domain
type. type.
7. Property Map 7. Property Map
A property map returns the properties defined for all entities in one A property map returns the properties defined for all entities in one
or more domains, e.g., the "location" property of entities in "pid" or more domains, e.g., the "location" property of entities in a
domain, and the "ASN" property of entities in "ipv4" and "ipv6" domain of type "pid", and the "ASN" property of entities in domains
domains. Section 10.4 gives an example of a property map request and of types "ipv4" and "ipv6". Section 10.4 gives an example of a
its response. property map request and its response.
Downloading the whole property map is a way for the Client to obtain Downloading the whole property map is a way for the Client to obtain
the Entity IDs that can be used as input for a Filtered Property Map the entity identifiers that can be used as input for a filtered
request. However, a whole property map may be too voluminous for a property map request. However, a whole property map may be too
Client that only wants the list of applicable Entity IDs. How to voluminous for a Client that only wants the list of applicable entity
obtain the list of entities of a filtered property map in a identifiers. How to obtain the list of entities of a filtered
simplified response is specified in Section 8. property map in a simplified response is specified in Section 8.
7.1. Media Type 7.1. Media Type
The media type of a property map is "application/alto-propmap+json". The media type of a property map is "application/alto-propmap+json".
7.2. HTTP Method 7.2. HTTP Method
The property map is requested using the HTTP GET method. The property map is requested using the HTTP GET method.
7.3. Accept Input Parameters 7.3. Accept Input Parameters
A Property Map has no Accept Input parameters. A property map has no Accept Input parameters.
7.4. Capabilities 7.4. Capabilities
The capabilities are defined by an object of type The capabilities are defined by an object of type
PropertyMapCapabilities: PropertyMapCapabilities:
object { object {
EntityPropertyMapping mappings; EntityPropertyMapping mappings;
} PropertyMapCapabilities; } PropertyMapCapabilities;
skipping to change at line 1390 skipping to change at line 1416
with fields: with fields:
mappings: A JSON object whose keys are names of entity domains and mappings: A JSON object whose keys are names of entity domains and
values are the supported entity properties of the corresponding values are the supported entity properties of the corresponding
entity domains. entity domains.
7.5. Uses 7.5. Uses
The "uses" field of a property map resource in an IRD entry specifies The "uses" field of a property map resource in an IRD entry specifies
the resources in this same IRD on which this property map directly the resources in this same IRD on which this property map directly
depends. It is an array of resource ID(s). This array identifies depends. It is an array of resource identifier(s). This array
the defining information resources associated with the resource- identifies the defining information resources associated with the
specific entity domains and properties that are indicated in this resource-specific entity domains and properties that are indicated in
resource. this resource.
7.6. Response 7.6. Response
If the entity domains in this property map depend on other resources, If the entity domains in this property map depend on other resources,
the "dependent-vtags" field in the "meta" field of the response MUST the "dependent-vtags" field in the "meta" field of the response MUST
be an array that includes the version tags of those resources, and be an array that includes the version tags of those resources, and
the order MUST be consistent with the "uses" field of this property the order MUST be consistent with the "uses" field of this property
map resource. The data component of a property map response is named map resource. The data component of a property map response is named
"property-map", which is a JSON object of type PropertyMapData, "property-map", which is a JSON object of type PropertyMapData,
where: where:
skipping to change at line 1441 skipping to change at line 1467
* If the entity is in a resource-specific entity domain, the ALTO * If the entity is in a resource-specific entity domain, the ALTO
server MUST only return self-defined properties and resource- server MUST only return self-defined properties and resource-
specific properties that depend on the same resource as the entity specific properties that depend on the same resource as the entity
does. The ALTO client MUST ignore any resource-specific property does. The ALTO client MUST ignore any resource-specific property
for this entity if the mapping between this resource-specific for this entity if the mapping between this resource-specific
property and this entity is not indicated, in the IRD, in the property and this entity is not indicated, in the IRD, in the
"mappings" capability of the property map resource. "mappings" capability of the property map resource.
* If the entity identifier is resource-agnostic, the ALTO server * If the entity identifier is resource-agnostic, the ALTO server
SHOULD return the self-defined properties and all the resource- SHOULD return the self-defined properties and all the resource-
specific properties that are defined in the property defining specific properties defined in the property-defining information
information resources indicated, in the IRD, in the "mappings" resources that are indicated, in the IRD, in the "mappings"
capability of the property map resource, unless property values capability of the property map resource, unless property values
can be omitted upon some inheritance rules. can be omitted upon some inheritance rules.
The ALTO server MAY omit property values that are inherited rather The ALTO server MAY omit property values that are inherited rather
than explicitly defined in order to achieve more compact encoding. than explicitly defined in order to achieve more compact encoding.
As a consequence, the ALTO Client MUST NOT assume inherited property As a consequence, the ALTO Client MUST NOT assume inherited property
values will all be present. If the Client needs inherited values, it values will all be present. If the Client needs inherited values, it
MUST use the entity domain's inheritance rules to deduce those MUST use the entity domain's inheritance rules to deduce those
values. values.
8. Filtered Property Map 8. Filtered Property Map
A filtered property map returns the values of a set of properties for A filtered property map returns the values of a set of properties for
a set of entities selected by the client. a set of entities selected by the client.
Sections 10.5, 10.6, 10.7, and 10.8 give examples of filtered Sections 10.5, 10.6, 10.7, and 10.8 give examples of filtered
property map requests and responses. property map requests and responses.
While the IRD lists all the names of the supported properties, it While the IRD lists all the names of the supported properties, it
only lists the names of the supported entity domains and not the only lists the names of the supported entity domains and not the
entity IDs. Sometimes a client may only want to know what entity IDs entity identifiers. Sometimes a client only wants to know what
it can provide as input to a filtered property map request but wants entity identifiers it can provide as input to a filtered property map
to avoid the burden of downloading the full property map. Or it may request but does not want to download the full property map, or it
want to check whether some given entity IDs are eligible for a query. may want to check whether some given entity identifiers are eligible
To support such a case, the filtered property map supports a for a query. To support these cases, the filtered property map
lightweight response with empty property values. supports a lightweight response with empty property values.
8.1. Media Type 8.1. Media Type
The media type of a property map resource is "application/alto- The media type of a property map resource is "application/alto-
propmap+json". propmap+json".
8.2. HTTP Method 8.2. HTTP Method
The filtered property map is requested using the HTTP POST method. The filtered property map is requested using the HTTP POST method.
skipping to change at line 1496 skipping to change at line 1522
support the following cases of client requests: support the following cases of client requests:
* The client wants the value of a selected set of properties for a * The client wants the value of a selected set of properties for a
selected set of entities; selected set of entities;
* The client wants all property values on all the entities; * The client wants all property values on all the entities;
* The client wants all entities for which a property is defined but * The client wants all entities for which a property is defined but
is not interested in their property values; or is not interested in their property values; or
* The client wants to cross-check whether some entity IDs are * The client wants to cross-check whether some entity identifiers
present in the Filtered Property Map but is not interested in are present in the filtered property map but is not interested in
their property values. their property values.
The third case is equivalent to querying the whole unfiltered The third case is equivalent to querying the whole unfiltered
property map, which can also be achieved with a GET request. Some property map, which can also be achieved with a GET request. Some
Clients, however, may prefer to systematically make filtered property Clients, however, may prefer to systematically make filtered property
map queries, where filtering parameters may sometimes be empty. map queries, where filtering parameters may sometimes be empty.
The JSON object ReqFilteredPropertyMap is specified as follows: The JSON object ReqFilteredPropertyMap is specified as follows:
object { object {
skipping to change at line 1531 skipping to change at line 1557
if they appeared only once. if they appeared only once.
properties: A list of properties to be returned for each entity. If properties: A list of properties to be returned for each entity. If
the list is empty, the ALTO Sever MUST interpret the list as if it the list is empty, the ALTO Sever MUST interpret the list as if it
contained a list of all properties currently defined in the contained a list of all properties currently defined in the
filtered property map. Each specified property MUST be included filtered property map. Each specified property MUST be included
in the list of properties in this resource's "capabilities" field in the list of properties in this resource's "capabilities" field
(see Section 8.4). The ALTO server MUST interpret entries (see Section 8.4). The ALTO server MUST interpret entries
appearing multiple times as if they appeared only once. This appearing multiple times as if they appeared only once. This
field is optional. If it is absent, the Server returns a property field is optional. If it is absent, the Server returns a property
value equal to the literal string "{}" for all the entity IDs of value equal to the literal string "{}" for all the entity
the "entities" field for which at least one property is defined. identifiers of the "entities" field for which at least one
property is defined.
Note that the field "properties" is optional. In addition, when the Note that the field "properties" is optional. In addition, when the
"entities" field is an empty list, it corresponds to a query for all "entities" field is an empty list, it corresponds to a query for all
applicable entity IDs of the filtered property map, with no current applicable entity identifiers of the filtered property map, with no
interest on any particular property. When the "entities" field is current interest on any particular property. When the "entities"
not empty, it allows the Client to check whether the listed entity field is not empty, it allows the Client to check whether the listed
IDs can be used as input to a filtered property map query. entity identifiers can be used as input to a filtered property map
query.
8.4. Capabilities 8.4. Capabilities
The capabilities are defined by an object of type The capabilities are defined by an object of type
PropertyMapCapabilities, as defined in Section 7.4. PropertyMapCapabilities, as defined in Section 7.4.
8.5. Uses 8.5. Uses
This is the same as the "uses" field of the Property Map resource This is the same as the "uses" field of the property map resource
(see Section 7.5). (see Section 7.5).
8.6. Filtered Property Map Response 8.6. Filtered Property Map Response
The response MUST indicate an error, using ALTO Protocol error The response MUST indicate an error, using ALTO Protocol error
handling, as defined in Section 8.5 of [RFC7285], if the request is handling, as defined in Section 8.5 of [RFC7285], if the request is
invalid. invalid.
Specifically, a filtered property map request can be invalid in the Specifically, a filtered property map request can be invalid in the
following cases: following cases:
* The input field "entities" is absent from the Client request. In * The input field "entities" is absent from the Client request. In
this case, the Server MUST return an "E_MISSING_FIELD" error as this case, the Server MUST return an "E_MISSING_FIELD" error as
defined in Section 8.5.2 of [RFC7285]. defined in Section 8.5.2 of [RFC7285].
* An entity identifier in the "entities" field of the request is * An entity identifier in the "entities" field of the request is
invalid. This occurs when: invalid. This occurs when:
- The domain of this entity is not defined in the "entity- - The domain of this entity is not defined in the "mappings"
domains" capability of this resource in the IRD, or capability of this resource in the IRD, or
- The entity identifier is not valid for the entity domain. - The entity identifier is not valid for the entity domain.
A valid entity identifier never generates an error, even if the A valid entity identifier never generates an error, even if the
filtered property map resource does not define any properties for filtered property map resource does not define any properties for
it. it.
If an entity identifier in the "entities" field of the request is If an entity identifier in the "entities" field of the request is
invalid, the ALTO server MUST return an "E_INVALID_FIELD_VALUE" invalid, the ALTO server MUST return an "E_INVALID_FIELD_VALUE"
error defined in Section 8.5.2 of [RFC7285], and the "value" field error defined in Section 8.5.2 of [RFC7285], and the "value" field
skipping to change at line 1605 skipping to change at line 1633
Some identifiers can be interpreted as both an entity name and a Some identifiers can be interpreted as both an entity name and a
property name, as is the case for "pid" if it were erroneously used property name, as is the case for "pid" if it were erroneously used
alone. In such a case, the Server SHOULD follow Section 8.5.2 of alone. In such a case, the Server SHOULD follow Section 8.5.2 of
[RFC7285], which says: [RFC7285], which says:
| For an E_INVALID_FIELD_VALUE error, the server may include an | For an E_INVALID_FIELD_VALUE error, the server may include an
| optional field named "field" in the "meta" field of the response, | optional field named "field" in the "meta" field of the response,
| to indicate the field that contains the wrong value. | to indicate the field that contains the wrong value.
The response to a valid request is the same as for the Property Map The response to a valid request is the same as for the property map
(see Section 7.6) except that: (see Section 7.6) except that:
* If the requested entities include entities with a resource- * If the requested entities include entities with a resource-
agnostic identifier, the "dependent-vtags" field in its "meta" agnostic identifier, the "dependent-vtags" field in its "meta"
field MUST include version tags of all dependent resources field MUST include version tags of all dependent resources
appearing in the "uses" field. appearing in the "uses" field.
* If the requested entities only include entities in resource- * If the requested entities only include entities in resource-
specific entity domains, the "dependent-vtags" field in its "meta" specific entity domains, the "dependent-vtags" field in its "meta"
field MUST include the version tags of the resources on which the field MUST include the version tags of the resources on which the
skipping to change at line 1677 skipping to change at line 1705
8.7. Entity Property Type Defined in This Document 8.7. Entity Property Type Defined in This Document
This document defines the entity property type "pid". This property This document defines the entity property type "pid". This property
type extends the ALTO endpoint property type "pid" defined in type extends the ALTO endpoint property type "pid" defined in
Section 7.1.1 of [RFC7285] as follows: the property has the same Section 7.1.1 of [RFC7285] as follows: the property has the same
semantics and applies to IPv4 and IPv6 addresses; the difference is semantics and applies to IPv4 and IPv6 addresses; the difference is
that the IPv4 and IPv6 addresses have evolved from the status of that the IPv4 and IPv6 addresses have evolved from the status of
endpoints to the status of entities. endpoints to the status of entities.
The defining information resource for property type MUST be a network The defining information resource for property type MUST be a network
map. This document requests an IANA registration for this property. map.
8.7.1. Entity Property Type: pid 8.7.1. Entity Property Type: pid
Identifier: pid Identifier: pid
Semantics: the intended semantics are the same as in [RFC7285] for Semantics: the intended semantics are the same as in [RFC7285] for
the ALTO endpoint property type "pid". the ALTO endpoint property type "pid".
Media type of defining information resource: application/alto- Media type of defining information resource: application/alto-
networkmap+json networkmap+json
Security considerations: for entity property type "pid" are the same Security considerations: for entity property type "pid" are the same
as documented in [RFC7285] for the ALTO endpoint property type as documented in [RFC7285] for the ALTO endpoint property type
"pid". "pid".
9. Impact on Legacy ALTO Servers and ALTO Clients 9. Impact on Legacy ALTO Servers and ALTO Clients
9.1. Impact on Endpoint Property Service 9.1. Impact on Endpoint Property Service
Since the Property Map and the Filtered Property Map defined in this Since the property map and the filtered property map defined in this
document provide a functionality that covers the EPS defined in document provide a functionality that covers the EPS defined in
Section 11.4 of [RFC7285], ALTO servers may prefer to provide Section 11.4 of [RFC7285], ALTO servers may prefer to provide
Property Map and Filtered Property Map in place of EPS. However, for property map and filtered property map in place of EPS. However, for
the legacy endpoint properties, it is recommended that ALTO servers the legacy endpoint properties, it is recommended that ALTO servers
also provide EPS so that legacy clients can still be supported. also provide EPS so that legacy clients can still be supported.
9.2. Impact on Resource-Specific Properties 9.2. Impact on Resource-Specific Properties
Section 10.8 of [RFC7285] defines two categories of endpoint Section 10.8 of [RFC7285] defines two categories of endpoint
properties: "resource-specific" and "global". Resource-specific properties: "resource-specific" and "global". Resource-specific
property names are prefixed with the ID of the resource they depend property names are prefixed with the identifier of the resource they
on, while global property names have no such prefix. The property depend on, while global property names have no such prefix. The
map and the filtered property map specified in this document define property map and the filtered property map specified in this document
similar categories of entity properties. The difference is that define similar categories of entity properties. The difference is
entity property maps do not define "global" entity properties. that entity property maps do not define "global" entity properties.
Instead, they define "self-defined" entity properties as a special Instead, they define self-defined entity properties as a special case
case of "resource-specific" entity properties, where the specific of "resource-specific" entity properties, where the specific resource
resource is the property map itself. This means that "self-defined" is the property map itself. This means that self-defined properties
properties are defined within the scope of the property map. are defined within the scope of the property map.
9.3. Impact on Other Properties 9.3. Impact on Other Properties
In the present extension, properties can be defined for sets of In the present extension, properties can be defined for sets of
entity addresses, rather than just individual endpoint addresses as entity addresses, rather than just individual endpoint addresses as
initially defined in [RFC7285]. This might change the semantics of a initially defined in [RFC7285]. This might change the semantics of a
property. These sets can be, for example, hierarchical IP address property. These sets can be, for example, hierarchical IP address
blocks. For instance, a property such as the fictitious "geo- blocks. For instance, a property such as the fictitious "geo-
location" defined for a set of IP addresses would have a value location" defined for a set of IP addresses would have a value
corresponding to a location representative of all the addresses in corresponding to a location representative of all the addresses in
skipping to change at line 1738 skipping to change at line 1766
10. Examples 10. Examples
In this document, the HTTP message bodies of all the examples use In this document, the HTTP message bodies of all the examples use
Unix-style line-ending character (%x0A) as the line separator. Unix-style line-ending character (%x0A) as the line separator.
10.1. Network Map 10.1. Network Map
The examples in this section use a very simple default network map: The examples in this section use a very simple default network map:
defaultpid: ipv4:0.0.0.0/0 ipv6:::/0 +-------------+--------------------------+
pid1: ipv4:192.0.2.0/25 | defaultpid: | ipv4:0.0.0.0/0 ipv6:::/0 |
pid2: ipv4:192.0.2.0/27 +-------------+--------------------------+
pid3: ipv4:192.0.3.0/28 | pid1: | ipv4:192.0.2.0/25 |
pid4: ipv4:192.0.3.16/28 +-------------+--------------------------+
| pid2: | ipv4:192.0.2.0/27 |
+-------------+--------------------------+
| pid3: | ipv4:192.0.3.0/28 |
+-------------+--------------------------+
| pid4: | ipv4:192.0.3.16/28 |
+-------------+--------------------------+
Figure 3: Example Default Network Map Table 3: Example Default Network Map
And another simple alternative network map: And another simple alternative network map:
defaultpid: ipv4:0.0.0.0/0 ipv6:::/0 +-------------+--------------------------+
pid1: ipv4:192.0.2.0/27 | defaultpid: | ipv4:0.0.0.0/0 ipv6:::/0 |
pid2: ipv4:192.0.3.0/27 +-------------+--------------------------+
| pid1: | ipv4:192.0.2.0/27 |
+-------------+--------------------------+
| pid2: | ipv4:192.0.3.0/27 |
+-------------+--------------------------+
Figure 4: Example Alternative Network Map Table 4: Example Alternative Network Map
10.2. Property Definitions 10.2. Property Definitions
Beyond "pid", the examples in this section use four additional, Beyond "pid", the examples in this section use four additional,
fictitious property types for entities of domain type "ipv4": fictitious property types for entities of domain type "ipv4":
"countrycode", "ASN", "ISP", and "state". These properties are "countrycode", "ASN", "ISP", and "state". These properties are
assumed to be resource-agnostic so their name is identical to their assumed to be resource-agnostic so their name is identical to their
type. The entities have the following values: type. The entities have the following values:
ISP ASN countrycode state +=====================+=========+=======+=============+=======+
ipv4:192.0.2.0/23: BitsRus - us - | | ISP | ASN | countrycode | state |
ipv4:192.0.2.0/28: - 65543 - NJ +=====================+=========+=======+=============+=======+
ipv4:192.0.2.16/28: - 65543 - CT | ipv4:192.0.2.0/23: | BitsRus | - | us | - |
ipv4:192.0.2.1: - - - PA +---------------------+---------+-------+-------------+-------+
ipv4:192.0.3.0/28: - 65544 - TX | ipv4:192.0.2.0/28: | - | 65543 | - | NJ |
ipv4:192.0.3.16/28: - 65544 - MN +---------------------+---------+-------+-------------+-------+
| ipv4:192.0.2.16/28: | - | 65543 | - | CT |
+---------------------+---------+-------+-------------+-------+
| ipv4:192.0.2.1: | - | - | - | PA |
+---------------------+---------+-------+-------------+-------+
| ipv4:192.0.3.0/28: | - | 65544 | - | TX |
+---------------------+---------+-------+-------------+-------+
| ipv4:192.0.3.16/28: | - | 65544 | - | MN |
+---------------------+---------+-------+-------------+-------+
Figure 5: Example Property Values for Internet Address Domains Table 5: Example Property Values for Internet Address Domains
The examples in this section use the property "region" for the PID The examples in this section use the property "region" for the PID
domain of the default network map with the following values: domain of the default network map with the following values:
region +=================+==========+
pid:defaultpid: - | | region |
pid:pid1: us-west +=================+==========+
pid:pid2: us-east | pid:defaultpid: | - |
pid:pid3: us-south +-----------------+----------+
pid:pid4: us-north | pid:pid1: | us-west |
+-----------------+----------+
| pid:pid2: | us-east |
+-----------------+----------+
| pid:pid3: | us-south |
+-----------------+----------+
| pid:pid4: | us-north |
+-----------------+----------+
Figure 6: Example Property Values for Default Network Map's PID Table 6: Example Property
Domain Values for Default Network
Map's PID Domain
Note that "-" means the value of the property for the entity is Note that "-" means the value of the property for the entity is
"undefined". So the entity would inherit a value for this property "undefined". So the entity would inherit a value for this property
by the inheritance rule if possible. For example, the value of the by the inheritance rule if possible. For example, the value of the
"ISP" property for "ipv4:192.0.2.1" is "BitsRus" because of "ISP" property for "ipv4:192.0.2.1" is "BitsRus" because of
"ipv4:192.0.2.0/24". But the "region" property for "pid:defaultpid" "ipv4:192.0.2.0/24". But the "region" property for "pid:defaultpid"
has no value because there is no entity from which it can inherit. has no value because there is no entity from which it can inherit.
Similar to the PID domain of the default network map, the examples in Similar to the PID domain of the default network map, the examples in
this section use the property "ASN" for the PID domain of the this section use the property "ASN" for the PID domain of the
alternative network map with the following values: alternative network map with the following values:
ASN +=================+=======+
pid:defaultpid: - | | ASN |
pid:pid1: 65543 +=================+=======+
pid:pid2: 65544 | pid:defaultpid: | - |
+-----------------+-------+
| pid:pid1: | 65543 |
+-----------------+-------+
| pid:pid2: | 65544 |
+-----------------+-------+
Figure 7: Example Property Values for Alternative Network Map's Table 7: Example
PID Domain Property Values for
Alternative Network
Map's PID Domain
10.3. Information Resource Directory (IRD) 10.3. Information Resource Directory (IRD)
The following IRD defines ALTO Server information resources that are The following IRD defines ALTO Server information resources that are
relevant to the Entity Property Service. It provides a property map relevant to the Entity Property Service. It provides a property map
for the "ISP" and "ASN" properties. The server could have provided a for the "ISP" and "ASN" properties. The server could have provided a
single property map for all four properties, but it does not, single property map for all four properties, but it does not,
presumably because the organization that runs the ALTO server presumably because the organization that runs the ALTO server
believes that a client is not necessarily interested in getting all believes that a client is not necessarily interested in getting all
four properties. four properties.
The server provides several filtered property maps. The first The server provides several filtered property maps. The first
returns all four properties, and the second returns only the "pid" returns all four properties, and the second returns only the "pid"
property for the default network map and the "alt-network-map". property for the default network map and the "alt-network-map".
The filtered property maps for the "ISP", "ASN", "countrycode", and The filtered property maps for the "ISP", "ASN", "countrycode", and
"state" properties do not depend on the default network map (it does "state" properties do not depend on the default network map (it does
not have a "uses" capability) because the definitions of those not have a "uses" capability) because the definitions of those
properties do not depend on the default network map. The Filtered properties do not depend on the default network map. The filtered
Property Map providing the "pid" property does have a "uses" property map providing the "pid" property does have a "uses"
capability for the default network map because the default network capability for the default network map because the default network
map defines the values of the "pid" property. map defines the values of the "pid" property.
Note that for legacy clients, the ALTO server provides an Endpoint Note that for legacy clients, the ALTO server provides an Endpoint
Property Service for the "pid" property defined for the endpoints of Property Service for the "pid" property defined for the endpoints of
the default network map and the "alt-network-map". the default network map and the "alt-network-map".
The server provides another filtered Property map resource, named The server provides another filtered Property map resource, named
"ane-dc-property-map", that returns fictitious properties named "ane-dc-property-map", that returns fictitious properties named
"storage-capacity", "ram", and "cpu" for ANEs that have a persistent "storage-capacity", "ram", and "cpu" for ANEs that have a persistent
identifier. The entity domain to which the ANEs belong is "self- identifier. The entity domain to which the ANEs belong is self-
defined" and valid only within the property map. defined and valid only within the property map.
The other property maps in the returned IRD are shown here for The other property maps in the returned IRD are shown here for
purposes of illustration. purposes of illustration.
GET /directory HTTP/1.1 GET /directory HTTP/1.1
Host: alto.example.com Host: alto.example.com
Accept: application/alto-directory+json,application/alto-error+json Accept: application/alto-directory+json,application/alto-error+json
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Length: 2713 Content-Length: 2713
skipping to change at line 1929 skipping to change at line 1990
"accepts": "application/alto-propmapparams+json", "accepts": "application/alto-propmapparams+json",
"capabilities": { "capabilities": {
"mappings": { "mappings": {
".ane" : [ "storage-capacity", "ram", "cpu" ] ".ane" : [ "storage-capacity", "ram", "cpu" ]
} }
} }
} }
} }
} }
Figure 8: Example IRD Figure 1: Example IRD
10.4. Full Property Map Example 10.4. Full Property Map Example
The following example uses the properties and IRD defined in The following example uses the properties and IRD defined in
Section 10.3 to retrieve a Property Map for entities with the "ISP" Section 10.3 to retrieve a property map for entities with the "ISP"
and "ASN" properties. and "ASN" properties.
Note that, to be compact, the response does not include the entity Note that, to be compact, the response does not include the entity
"ipv4:192.0.2.1" because values of all those properties for this "ipv4:192.0.2.1" because values of all those properties for this
entity are inherited from other entities. entity are inherited from other entities.
Also note that the entities "ipv4:192.0.2.0/28" and Also note that the entities "ipv4:192.0.2.0/28" and
"ipv4:192.0.2.16/28" are merged into "ipv4:192.0.2.0/27" because they "ipv4:192.0.2.16/28" are merged into "ipv4:192.0.2.0/27" because they
have the same value of the "ASN" property. The same rule applies to have the same value of the "ASN" property. The same rule applies to
the entities "ipv4:192.0.3.0/28" and "ipv4:192.0.3.16/28". Both the entities "ipv4:192.0.3.0/28" and "ipv4:192.0.3.16/28". Both
skipping to change at line 2133 skipping to change at line 2194
"alt-network-map.pid": "pid2"}, "alt-network-map.pid": "pid2"},
"ipv4:192.0.3.16/28": {"default-network-map.pid": "pid4", "ipv4:192.0.3.16/28": {"default-network-map.pid": "pid4",
"alt-network-map.pid": "pid2"} "alt-network-map.pid": "pid2"}
} }
} }
10.8. Filtered Property Map Example #4 10.8. Filtered Property Map Example #4
Here is an example of using the filtered property map to query the Here is an example of using the filtered property map to query the
regions for several PIDs in "default-network-map". The "region" regions for several PIDs in "default-network-map". The "region"
property is specified as a "self-defined" property, i.e., the values property is specified as a self-defined property, i.e., the values of
of this property are defined by this property map resource. this property are defined by this property map resource.
POST /propmap/lookup/region HTTP/1.1 POST /propmap/lookup/region HTTP/1.1
Host: alto.example.com Host: alto.example.com
Accept: application/alto-propmap+json,application/alto-error+json Accept: application/alto-propmap+json,application/alto-error+json
Content-Length: 132 Content-Length: 132
Content-Type: application/alto-propmapparams+json Content-Type: application/alto-propmapparams+json
{ {
"entities" : ["default-network-map.pid:pid1", "entities" : ["default-network-map.pid:pid1",
"default-network-map.pid:pid2"], "default-network-map.pid:pid2"],
skipping to change at line 2183 skipping to change at line 2244
on several ANEs defined in this property map. on several ANEs defined in this property map.
POST /propmap/lookup/ane-dc HTTP/1.1 POST /propmap/lookup/ane-dc HTTP/1.1
Host: alto.example.com Host: alto.example.com
Accept: application/alto-propmap+json,application/alto-error+json Accept: application/alto-propmap+json,application/alto-error+json
Content-Length: 155 Content-Length: 155
Content-Type: application/alto-propmapparams+json Content-Type: application/alto-propmapparams+json
{ {
"entities" : [".ane:dc21", "entities" : [".ane:dc21",
".ane:dc45.srv9", ".ane:dc45-srv9",
".ane:dc6.srv-cluster8"], ".ane:dc6-srvcluster8"],
"properties" : [ "storage-capacity", "cpu"] "properties" : [ "storage-capacity", "cpu"]
} }
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Length: 295 Content-Length: 295
Content-Type: application/alto-propmap+json Content-Type: application/alto-propmap+json
{ {
"meta" : { "meta" : {
}, },
"property-map": { "property-map": {
".ane:dc21": ".ane:dc21":
{"storage-capacity" : 40000, "cpu" : 500}, {"storage-capacity" : 40000, "cpu" : 500},
".ane:dc45.srv9": ".ane:dc45-srv9":
{"storage-capacity" : 100, "cpu" : 20}, {"storage-capacity" : 100, "cpu" : 20},
".ane:dc6.srv-cluster8": ".ane:dc6-srvcluster8":
{"storage-capacity" : 6000, "cpu" : 100} {"storage-capacity" : 6000, "cpu" : 100}
} }
} }
11. Security Considerations 11. Security Considerations
Both Property Map and Filtered Property Map defined in this document Both property map and filtered property map defined in this document
fit into the architecture of the ALTO base protocol, and hence the fit into the architecture of the ALTO base protocol, and hence the
Security Considerations (Section 15 of [RFC7285]) of the base Security Considerations (Section 15 of [RFC7285]) of the base
protocol fully apply: authenticity and integrity of ALTO information protocol fully apply: authenticity and integrity of ALTO information
(i.e., authenticity and integrity of Property Maps), potential (i.e., authenticity and integrity of property maps), potential
undesirable guidance from authenticated ALTO information (e.g., undesirable guidance from authenticated ALTO information (e.g.,
potentially imprecise or even wrong value of a property such as geo- potentially imprecise or even wrong value of a property such as geo-
location), confidentiality of ALTO information (e.g., exposure of a location), confidentiality of ALTO information (e.g., exposure of a
potentially sensitive entity property such as geo-location), privacy potentially sensitive entity property such as geo-location), privacy
for ALTO users, and availability of ALTO services should all be for ALTO users, and availability of ALTO services should all be
considered. considered.
ALTO clients using this extension should in addition be aware that ALTO clients using this extension should in addition be aware that
the entity properties they require may convey more details than the the entity properties they require may convey more details than the
endpoint properties conveyed by using [RFC7285]. Client requests may endpoint properties conveyed by using [RFC7285]. Client requests may
reveal details of their activity or plans thereof such that a reveal details of their activity or plans thereof such that a
malicious Server, which is in a position to do so, may monetize or malicious Server, which is in a position to do so, may monetize or
use for attacks or undesired surveillance. Likewise, ALTO Servers use for attacks or undesired surveillance. Likewise, ALTO Servers
expose entities and properties related to specific parts of the expose entities and properties related to specific parts of the
infrastructure that reveal details of capabilities, locations, or infrastructure that reveal details of capabilities, locations, or
resource availability. These details may be maliciously used for resource availability. These details may be maliciously used for
competition purposes, or to cause resource shortage or undesired competition purposes, or to cause resource shortage or undesired
publication. publication.
To address these concerns, the Property Maps provided by this To address these concerns, the property maps provided by this
extension require additional attention to two security considerations extension require additional attention to two security considerations
discussed in: Section 15.2 ("Potential Undesirable Guidance from discussed in: Section 15.2 ("Potential Undesirable Guidance from
Authenticated ALTO Information") of [RFC7285] and Section 15.3 Authenticated ALTO Information") of [RFC7285] and Section 15.3
("Confidentiality of ALTO Information") of [RFC7285]. Threats to the ("Confidentiality of ALTO Information") of [RFC7285]. Threats to the
availability of the ALTO service caused by highly demanding queries availability of the ALTO service caused by highly demanding queries
should be addressed as specified in Section 15.5 of [RFC7285]. should be addressed as specified in Section 15.5 of [RFC7285].
* Potential undesirable guidance from authenticated ALTO * Potential undesirable guidance from authenticated ALTO
information: this can be caused by Property values that change information: this can be caused by Property values that change
over time and thus lead to performance degradation or system over time and thus lead to performance degradation or system
skipping to change at line 2295 skipping to change at line 2356
MUST include security considerations that explain why this MUST include security considerations that explain why this
property type is required for ALTO-based operations. property type is required for ALTO-based operations.
The risk of ALTO information being leaked to malicious Clients or The risk of ALTO information being leaked to malicious Clients or
third parties is addressed similarly to Section 7 of [RFC8896]. third parties is addressed similarly to Section 7 of [RFC8896].
ALTO clients and servers SHOULD support TLS 1.3 [RFC8446]. ALTO clients and servers SHOULD support TLS 1.3 [RFC8446].
12. IANA Considerations 12. IANA Considerations
This document defines additional application/alto-* media types, This document defines additional application/alto-* media types,
which are listed in Table 1. It defines the "ALTO Entity Domain which are listed in Table 8. It defines the "ALTO Entity Domain
Types" registry that extends the "ALTO Address Types" registry Types" registry that extends the "ALTO Address Types" registry
defined in [RFC7285]. It also defines the "ALTO Entity Property defined in [RFC7285]. It also defines the "ALTO Entity Property
Types" registry that extends the "ALTO Endpoint Property Types" Types" registry that extends the "ALTO Endpoint Property Types"
registry defined in [RFC7285]. registry defined in [RFC7285].
+=============+=========================+===============+ +=============+=========================+===============+
| Type | Subtype | Specification | | Type | Subtype | Specification |
+=============+=========================+===============+ +=============+=========================+===============+
| application | alto-propmap+json | Section 7.1 | | application | alto-propmap+json | Section 7.1 |
+-------------+-------------------------+---------------+ +-------------+-------------------------+---------------+
| application | alto-propmapparams+json | Section 8.1 | | application | alto-propmapparams+json | Section 8.1 |
+-------------+-------------------------+---------------+ +-------------+-------------------------+---------------+
Table 1: Additional ALTO Media Types Table 8: Additional ALTO Media Types
12.1. application/alto-propmap+json Media Type 12.1. application/alto-propmap+json Media Type
Type name: Type name:
application application
Subtype name: Subtype name:
alto-propmap+json alto-propmap+json
Required parameters: Required parameters:
skipping to change at line 2436 skipping to change at line 2497
Author: Author:
See Authors' Addresses section. See Authors' Addresses section.
Change controller: Change controller:
Internet Engineering Task Force (iesg@ietf.org). Internet Engineering Task Force (iesg@ietf.org).
12.3. ALTO Entity Domain Types Registry 12.3. ALTO Entity Domain Types Registry
IANA has created and will maintain the "ALTO Entity Domain Types" IANA has created and will maintain the "ALTO Entity Domain Types"
registry listed in Table 2. The first row lists information items registry listed in Table 9. The first row lists information items
that must be provided with each registered entity domain type. that must be provided with each registered entity domain type.
Section 12.3.2 specifies how to document these items and in addition Section 12.3.2 specifies how to document these items and in addition
provides guidance on the security considerations item that must be provides guidance on the security considerations item that must be
documented. documented.
+==========+===========+=============+======================+=======+ +==========+===========+=============+======================+=======+
|Identifier|Entity |Hierarchy and|Media Type of Defining|Mapping| |Identifier|Entity |Hierarchy and|Media Type of Defining|Mapping|
| |Identifier |Inheritance |Resource |to ALTO| | |Identifier |Inheritance |Resource |to ALTO|
| |Encoding | | |Address| | |Encoding | | |Address|
| | | | |Type | | | | | |Type |
skipping to change at line 2458 skipping to change at line 2519
|ipv4 |See Section|See |application/alto- |true | |ipv4 |See Section|See |application/alto- |true |
| |6.1.1 |Section 6.1.3|networkmap+json | | | |6.1.1 |Section 6.1.3|networkmap+json | |
+----------+-----------+-------------+----------------------+-------+ +----------+-----------+-------------+----------------------+-------+
|ipv6 |See Section|See |application/alto- |true | |ipv6 |See Section|See |application/alto- |true |
| |6.1.2 |Section 6.1.3|networkmap+json | | | |6.1.2 |Section 6.1.3|networkmap+json | |
+----------+-----------+-------------+----------------------+-------+ +----------+-----------+-------------+----------------------+-------+
|pid |See |None |application/alto- |false | |pid |See |None |application/alto- |false |
| |Section 6.2| |networkmap+json | | | |Section 6.2| |networkmap+json | |
+----------+-----------+-------------+----------------------+-------+ +----------+-----------+-------------+----------------------+-------+
Table 2: ALTO Entity Domain Types Table 9: ALTO Entity Domain Types
This registry serves two purposes. First, it ensures uniqueness of This registry serves two purposes. First, it ensures uniqueness of
identifiers referring to ALTO entity domain types. Second, it states identifiers referring to ALTO entity domain types. Second, it states
the requirements for allocated entity domain types. the requirements for allocated entity domain types.
As specified in Section 5.1.1, identifiers prefixed with "priv:" are As specified in Section 5.1.1, identifiers prefixed with "priv:" are
reserved for Private Use without a need to register with IANA reserved for Private Use without a need to register with IANA
12.3.1. Consistency Procedure between ALTO Address Types Registry and 12.3.1. Consistency Procedure between ALTO Address Types Registry and
ALTO Entity Domain Types Registry ALTO Entity Domain Types Registry
skipping to change at line 2497 skipping to change at line 2558
* If an ALTO entity domain type has the same identifier as an ALTO * If an ALTO entity domain type has the same identifier as an ALTO
address type, their address encodings MUST be compatible. address type, their address encodings MUST be compatible.
To achieve this consistency, the following items MUST be checked To achieve this consistency, the following items MUST be checked
before registering a new ALTO entity domain type in a future before registering a new ALTO entity domain type in a future
document: document:
* Whether the "ALTO Address Types" registry contains an address type * Whether the "ALTO Address Types" registry contains an address type
that can be used as an identifier for the candidate entity domain that can be used as an identifier for the candidate entity domain
type identifier. This has been done for the identifiers "ipv4" type identifier. This has been done for the identifiers "ipv4"
and "ipv6" of Table 2. and "ipv6" of Table 9.
* Whether the candidate entity domain type identifier can * Whether the candidate entity domain type identifier can
potentially be an endpoint address type, as defined in Sections potentially be an endpoint address type, as defined in Sections
2.1 and 2.2 of [RFC7285]. 2.1 and 2.2 of [RFC7285].
When a new ALTO entity domain type is registered, the consistency When a new ALTO entity domain type is registered, the consistency
with the "ALTO Address Types" registry MUST be ensured by the with the "ALTO Address Types" registry MUST be ensured by the
following procedure: following procedure:
* Test: Do corresponding entity domain type identifiers match a * Test: Do corresponding entity domain type identifiers match a
skipping to change at line 2527 skipping to change at line 2588
+ If no: Define a new ALTO entity domain type identifier + If no: Define a new ALTO entity domain type identifier
and use it to register a new address type in the "ALTO and use it to register a new address type in the "ALTO
Address Types" registry following Section 14.4 of Address Types" registry following Section 14.4 of
[RFC7285]. [RFC7285].
o Use the new ALTO entity domain type identifier to register a o Use the new ALTO entity domain type identifier to register a
new ALTO entity domain type in the "ALTO Entity Domain new ALTO entity domain type in the "ALTO Entity Domain
Types" registry following Section 12.3.2 of this document. Types" registry following Section 12.3.2 of this document.
- If no (e.g., pid name, ane name, or country code): Proceed with - If no (e.g., PID name, ANE name, or "countrycode"): Proceed
the ALTO Entity Domain Type registration as described in with the ALTO Entity Domain Type registration as described in
Section 12.3.2. Section 12.3.2.
12.3.2. ALTO Entity Domain Type Registration Process 12.3.2. ALTO Entity Domain Type Registration Process
New ALTO entity domain types are assigned after IETF Review [RFC8126] New ALTO entity domain types are assigned after IETF Review [RFC8126]
to ensure that proper documentation regarding the new ALTO entity to ensure that proper documentation regarding the new ALTO entity
domain types and their security considerations has been provided. domain types and their security considerations has been provided.
RFCs defining new entity domain types MUST indicate how an entity in RFCs defining new entity domain types MUST indicate how an entity in
a registered type of domain is encoded as an EntityID and, if a registered type of domain is encoded as an EntityID and, if
applicable, the rules defining the entity hierarchy and property applicable, provide the rules for defining the entity hierarchy and
inheritance. Updates and deletions of ALTO entity domains types property inheritance. Updates and deletions of ALTO entity domains
follow the same procedure. types follow the same procedure.
Registered ALTO entity domain type identifiers MUST conform to the Registered ALTO entity domain type identifiers MUST conform to the
syntactical requirements specified in Section 5.1.2. Identifiers are syntactical requirements specified in Section 5.1.2. Identifiers are
to be recorded and displayed as strings. to be recorded and displayed as strings.
Requests to IANA to add a new value to the "ALTO Entity Domain Types" Requests to IANA to add a new value to the "ALTO Entity Domain Types"
registry MUST include the following information: registry MUST include the following information:
Identifier: The name of the desired ALTO entity domain type. Identifier: The name of the desired ALTO entity domain type.
skipping to change at line 2589 skipping to change at line 2650
same identifier. same identifier.
Security Considerations: In some usage scenarios, entity identifiers Security Considerations: In some usage scenarios, entity identifiers
carried in ALTO Protocol messages may reveal information about an carried in ALTO Protocol messages may reveal information about an
ALTO client or an ALTO service provider. Applications and ALTO ALTO client or an ALTO service provider. Applications and ALTO
service providers using addresses of the registered type should be service providers using addresses of the registered type should be
cognizant of how (or if) the addressing scheme relates to private cognizant of how (or if) the addressing scheme relates to private
information and network proximity. information and network proximity.
IANA has registered the identifiers "ipv4", "ipv6", and "pid", as IANA has registered the identifiers "ipv4", "ipv6", and "pid", as
shown in Table 2. shown in Table 9.
12.4. ALTO Entity Property Types Registry 12.4. ALTO Entity Property Types Registry
IANA has created and will maintain the "ALTO Entity Property Types" IANA has created and will maintain the "ALTO Entity Property Types"
registry, which is listed in Table 3. registry, which is listed in Table 10.
This registry extends the "ALTO Endpoint Property Types" registry, This registry extends the "ALTO Endpoint Property Types" registry,
defined in [RFC7285], in that a property type is defined for one or defined in [RFC7285], in that a property type is defined for one or
more entity domains, rather than just for IPv4 and IPv6 Internet more entity domains, rather than just for IPv4 and IPv6 Internet
address domains. An entry in this registry is an ALTO entity address domains. An entry in this registry is an ALTO entity
property type defined in Section 5.2.1. Thus, a registered ALTO property type defined in Section 5.2.1. Thus, a registered ALTO
entity property type identifier MUST conform to the syntactical entity property type identifier MUST conform to the syntactical
requirements specified in that section. requirements specified in that section.
As specified in Section 5.2.1, identifiers prefixed with "priv:" are As specified in Section 5.2.1, identifiers prefixed with "priv:" are
reserved for Private Use without a need to register with IANA. reserved for Private Use without a need to register with IANA.
The first row of Table 3 lists information items that must be The first row of Table 10 lists information items that must be
provided with each registered entity property type. provided with each registered entity property type.
+============+====================+=================================+ +============+====================+=================================+
| Identifier | Intended Semantics | Media Type of | | Identifier | Intended Semantics | Media Type of |
| | | Defining Resource | | | | Defining Resource |
+============+====================+=================================+ +============+====================+=================================+
| pid | See Section 7.1.1 | application/alto- | | pid | See Section 7.1.1 | application/alto- |
| | of [RFC7285] | networkmap+json | | | of [RFC7285] | networkmap+json |
+------------+--------------------+---------------------------------+ +------------+--------------------+---------------------------------+
Table 3: ALTO Entity Property Types Table 10: ALTO Entity Property Types
New ALTO entity property types are assigned after IETF Review New ALTO entity property types are assigned after IETF Review
[RFC8126] to ensure that proper documentation regarding the new ALTO [RFC8126] to ensure that proper documentation regarding the new ALTO
entity property types and their security considerations has been entity property types and their security considerations has been
provided. RFCs defining new entity property types SHOULD indicate provided. RFCs defining new entity property types SHOULD indicate
how a property of a registered type is encoded as a property name. how a property of a registered type is encoded as a property name.
Updates and deletions of ALTO entity property types follow the same Updates and deletions of ALTO entity property types follow the same
procedure. procedure.
Requests to IANA to add a new value to the registry MUST include the Requests to IANA to add a new value to the registry MUST include the
skipping to change at line 2660 skipping to change at line 2721
to ALTO clients. ALTO service providers should be cognizant of to ALTO clients. ALTO service providers should be cognizant of
the security ramifications related to the exposure of an entity the security ramifications related to the exposure of an entity
property. property.
In security considerations, the request should also discuss the In security considerations, the request should also discuss the
sensitivity of the information and why it is required for ALTO-based sensitivity of the information and why it is required for ALTO-based
operations. Regarding this discussion, the request SHOULD follow the operations. Regarding this discussion, the request SHOULD follow the
recommendations of the "ALTO Endpoint Property Types" registry in recommendations of the "ALTO Endpoint Property Types" registry in
Section 14.3 of [RFC7285]. Section 14.3 of [RFC7285].
IANA has registered the identifier "pid", which is listed in Table 3. IANA has registered the identifier "pid", which is listed in
Semantics for this property are documented in Section 7.1.1 of Table 10. Semantics for this property are documented in
[RFC7285]. No security issues related to the exposure of a "pid" Section 7.1.1 of [RFC7285]. No security issues related to the
identifier are considered, as it is exposed with the Network Map exposure of a "pid" identifier are considered, as it is exposed with
Service defined and mandated in [RFC7285]. the Network Map Service defined and mandated in [RFC7285].
13. References 13. References
13.1. Normative References 13.1. Normative References
[ISO3166-1] [ISO3166-1]
International Organization for Standardization, "Codes for International Organization for Standardization, "Codes for
the representation of names of countries and their the representation of names of countries and their
subdivisions -- Part 1: Country codes", ISO 3166-1:2020, subdivisions -- Part 1: Country codes", ISO 3166-1:2020,
August 2020. August 2020.
skipping to change at line 2764 skipping to change at line 2825
Nadeau, "An Architecture for the Interface to the Routing Nadeau, "An Architecture for the Interface to the Routing
System", RFC 7921, DOI 10.17487/RFC7921, June 2016, System", RFC 7921, DOI 10.17487/RFC7921, June 2016,
<https://www.rfc-editor.org/info/rfc7921>. <https://www.rfc-editor.org/info/rfc7921>.
[RFC8896] Randriamasy, S., Yang, R., Wu, Q., Deng, L., and N. [RFC8896] Randriamasy, S., Yang, R., Wu, Q., Deng, L., and N.
Schwan, "Application-Layer Traffic Optimization (ALTO) Schwan, "Application-Layer Traffic Optimization (ALTO)
Cost Calendar", RFC 8896, DOI 10.17487/RFC8896, November Cost Calendar", RFC 8896, DOI 10.17487/RFC8896, November
2020, <https://www.rfc-editor.org/info/rfc8896>. 2020, <https://www.rfc-editor.org/info/rfc8896>.
[RFC9241] Seedorf, J., Yang, Y., Ma, K., Peterson, J., and J. Zhang, [RFC9241] Seedorf, J., Yang, Y., Ma, K., Peterson, J., and J. Zhang,
"Content Delivery Network Interconnection (CDNI) Request "Content Delivery Network Interconnection (CDNI) Footprint
Routing: CDNI Footprint and Capabilities Advertisement and Capabilities Advertisement Using Application-Layer
using ALTO", RFC 9241, DOI 10.17487/RFC9241, May 2022, Traffic Optimization (ALTO)", RFC 9241,
DOI 10.17487/RFC9241, June 2022,
<https://www.rfc-editor.org/info/rfc9241>. <https://www.rfc-editor.org/info/rfc9241>.
Appendix A. Features Introduced with the Entity Property Maps Extension Appendix A. Features Introduced with the Entity Property Maps Extension
The Entity Property Maps extension described in this document The entity property maps extension described in this document
introduces a number of features that are summarized in table below. introduces a number of features that are summarized in table below.
The first column provides the name of the feature. The second column The first column provides the name of the feature. The second column
provides the section number of this document that gives a high-level provides the section number of this document that gives a high-level
description of the feature. The third column provides the section description of the feature. The third column provides the section
number of this document that gives a normative description relating number of this document that gives a normative description relating
to the feature, when applicable. to the feature, when applicable.
+======================+=============+======================+ +=======================+=============+======================+
| Feature | High-Level | Related Normative | | Feature | High-Level | Related Normative |
| | Description | Description | | | Description | Description |
+======================+=============+======================+ +=======================+=============+======================+
| Entity | Section 3.1 | Section 5.1.3 | | Entity | Section 3.1 | Section 5.1.3 |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Entity domain (ED) | Section 3.2 | | | Entity domain | Section 3.2 | |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Entity domain type | Section | Section 5.1.1 | | Entity domain type | Section | Section 5.1.1 |
| | 3.2.1 | | | | 3.2.1 | |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Entity domain name | Section | Section 5.1.2 | | Entity domain name | Section | Section 5.1.2 |
| | 3.2.2 | | | | 3.2.2 | |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Entity property (EP) | Section 3.3 | Sections 5.2, 5.2.1, | | Entity property type | Section 3.3 | Sections 5.2, 5.2.1, |
| type | | 5.2.2, and 5.2.3 | | | | 5.2.2, and 5.2.3 |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Entity property map | Section 3.4 | Sections 7 and 8 | | Entity property map | Section 3.4 | Sections 7 and 8 |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Resource-specific ED | Section 4.2 | Sections 5.1.2 and | | Resource-specific | Section 4.2 | Sections 5.1.2 and |
| name | | 5.1.2.1 | | entity domain name | | 5.1.2.1 |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Resource-specific EP | Section 4.3 | Section 5.2.3 | | Resource-specific | Section 4.3 | Section 5.2.3 |
| value | | | | entity property value | | |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Entity Hierarchy and | Section 4.4 | Section 5.1.4 | | Entity Hierarchy and | Section 4.4 | Section 5.1.4 |
| property inheritance | | | | property inheritance | | |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
| Defining information | Sections | Sections 12.3.2 and | | Defining information | Sections | Sections 12.3.2 and |
| resource | 4.6 and 4.7 | 12.4 | | resource | 4.6 and 4.7 | 12.4 |
+----------------------+-------------+----------------------+ +-----------------------+-------------+----------------------+
Table 4: Features Introduced with ALTO Entity Property Maps Table 11: Features Introduced with ALTO Entity Property Maps
Acknowledgments Acknowledgments
The authors would like to thank Dawn Chen and Shenshen Chen for their The authors would like to thank Dawn Chen and Shenshen Chen for their
contributions to earlier drafts. Thank you also to Qiao Xiang, Shawn contributions to earlier drafts. Thank you also to Qiao Xiang, Shawn
Lin, Xin Wang, and Vijay Gurbani for fruitful discussions. Last, big Lin, and Xin Wang for fruitful discussions. Last, big thanks to
thanks to Danny Perez and Luis Contreras for their substantial Danny Perez and Luis Contreras for their substantial working group
working group review feedback and suggestions for improving this review feedback and suggestions for improving this document, to Vijay
document, to Vijay Gurbani, ALTO WG Chair, and Martin Duke, Transport Gurbani, ALTO WG Chair, and Martin Duke, Transport Area Director, for
Area Director, for their thorough review, discussions, guidance, and their thorough review, discussions, guidance, and shepherding, which
shepherding, which further helped to enrich this document. further helped to enrich this document.
Authors' Addresses Authors' Addresses
Wendy Roome Wendy Roome
Nokia Bell Labs (Retired) Nokia Bell Labs (Retired)
124 Burlington Rd 124 Burlington Rd
Murray Hill, NJ 07974 Murray Hill, NJ 07974
United States of America United States of America
Phone: +1-908-464-6975 Phone: +1-908-464-6975
Email: wendy@wdroome.com Email: wendy@wdroome.com
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