Just realized I forgot to attach the draft...
Best,
Jensen
On Wed, Apr 17, 2019 at 11:40 PM Jensen Zhang <[email protected]>
wrote:
> Hi Sabine,
>
> Thanks for your reply. Actually, you can find this example from our old
> version of the IETF104 unified properties slides (p11) [1]. We removed it
> from the final slides because it is too complex. But as you can see, design
> option 2 can support this case without any ambiguity.
>
> And I agree that we should make sure we don't miss any potential cases.
> But if we really want to consider some other case which current design
> option 2 cannot support, we should give a concrete (even fictitious)
> example. So far, I have not come up with an example which cannot work using
> design option 2.
>
> I finished a draft to illustrate design option 2. The attachment is the
> text file of the draft. I have not submitted this revision yet because we
> have not achieved an agreement on the final design.
>
> And also, I made a deck of slides [2] illustrating the updates and issues
> I have not figured out. We talked about the early part of the document
> updates in our weekly meeting this morning. But most of them have not been
> discussed. It will be great if you can take a quick look. In particular, p7
> shows how to make design option 2 backward-compatible with design option 1;
> p8 talks about the IANA registry issue; and I give a solution proposal on
> p9 (not included in the draft revision yet). I would like to see how you
> think about the current revision and the introduced issue.
>
> I am looking forward to your feedback.
>
> [1]
> https://drive.google.com/file/d/19NO5MgQIGtioxC-lajkADyxpuDmLwmHt/view?usp=sharing
> [2]
> https://docs.google.com/presentation/d/1ooJHN6VhzPl3MqcbsMw442BnrPIupR_tyHOKa-18pSc/edit?usp=sharing
>
> Thanks,
> Jensen
>
>
> On Wed, Apr 17, 2019 at 9:37 AM Randriamasy, Sabine (Nokia -
> FR/Paris-Saclay) <[email protected]> wrote:
>
>> Hi Jensen,
>>
>>
>>
>> Thanks for your answer. I was just resuming one use case that was
>> motivating the need to disambiguate resource dependencies.
>>
>>
>>
>> Would it be possible to look at the example where:
>>
>> - entity = pid:MYPID
>>
>> - property = FCI.capability10
>>
>> Property definition depends on FCI map, entity ID depends on a Network
>> map.
>>
>>
>>
>> And write an example for:
>>
>> - IRD entry for filtered/unfiltered propmaps,
>>
>> - example request ,
>>
>> - Example response
>>
>>
>>
>> The purpose is to illustrate the problem and collect more WG feedback.
>> Maybe the use case above does not exist but we may want to make sure we
>> don’t miss other cases where both entity ID and property depend on an
>> information resource.
>>
>> Thanks,
>>
>> Sabine
>>
>>
>>
>>
>>
>>
>>
>> *From:* Jensen Zhang <[email protected]>
>> *Sent:* Thursday, April 11, 2019 6:35 PM
>> *To:* Randriamasy, Sabine (Nokia - FR/Paris-Saclay) <
>> [email protected]>
>> *Cc:* IETF ALTO <[email protected]>; Richard Yang <[email protected]>
>> *Subject:* Re: Final Decision of Unified Properties Design before Moving
>> to WGLC
>>
>>
>>
>> Hi Sabine,
>>
>>
>>
>> I remember that is the problem I proposed to motivate the design option
>> 1. But in design option 2, we no longer have this problem. Let me clarify a
>> little bit:
>>
>>
>>
>> Why a property map requires dependencies? Because the client requires
>> other resources to help it to understand the information on a property map.
>> More specifically, the client wants to understand every key appearing in a
>> property map. Those keys include entity identifiers and property names.
>> Each entity identifier or property name may be defined in another resource
>> (its origin). Without this resource, the client cannot understand the
>> corresponding entity identifier or property name. That is one of the
>> insights of design option 2.
>>
>>
>>
>> In design option 2, we require the server to explicitly expose the origin
>> of each entity identifier and property name to avoid ambiguity. But we
>> notice that each entity identifier or property name has exactly one origin.
>> I cannot come up with an example where an entity identifier or a property
>> map has more than one origin.
>>
>>
>>
>> In your PID-FCI example, if FCI capabilities are defined on PIDs, the map
>> would depend on both Network Map and FCI map. But the Network Map is the
>> origin of PIDs, and the FCI map is the origin of FCI capabilities. So each
>> key still has one dependent resource.
>>
>>
>>
>> I'm not sure if we will have an example where the entity identifier
>> encoding is so complex that the client needs multiple information resources
>> to parse this entity identifier correctly in the future. But so far, I
>> cannot come up with such a real example. If we consider how to handle this,
>> we may take a risk dragging on the overdesign.
>>
>>
>>
>> Best,
>>
>> Jensen
>>
>>
>>
>>
>>
>> On Wed, Apr 10, 2019 at 6:01 AM Randriamasy, Sabine (Nokia -
>> FR/Paris-Saclay) <[email protected]> wrote:
>>
>> Hi Jensen,
>>
>>
>>
>> Thanks a lot for the provided examples. It will be indeed be helpful to
>> present a fully fleshed example for the 2 options and the related pros &
>> cons.
>>
>> That is: example information resource in IRD, example request and
>> response.
>>
>>
>>
>> My question on option 2 and in general is to see how to handle examples
>> where a property map depends on 2 or more resources.
>>
>> For example, if FCI capabilities are defined on PIDs, the map would
>> depend on both Network Map and FCI map.
>>
>> Questions:
>>
>> - does this example make sense?
>>
>> - what is the probability of having similar cases of property maps
>> depending on multiple other information resources?
>>
>>
>>
>> Thanks,
>>
>> Sabine
>>
>>
>>
>>
>>
>>
>>
>> *From:* Jensen Zhang <[email protected]>
>> *Sent:* Tuesday, April 09, 2019 4:28 PM
>> *To:* Randriamasy, Sabine (Nokia - FR/Paris-Saclay) <
>> [email protected]>
>> *Cc:* IETF ALTO <[email protected]>; Richard Yang <[email protected]>
>> *Subject:* Final Decision of Unified Properties Design before Moving to
>> WGLC
>>
>>
>>
>> Hi all,
>>
>>
>>
>> Authors of the document draft-ietf-alto-unified-props-new had a
>> discussion about the unified properties design last week. We reviewed two
>> design options proposed in IETF 104 and analyzed the pros and cons of both.
>>
>>
>>
>> For the design option 1, binding resource dependencies to property type,
>> it is easy to process but hard to understand (we spend a lot of time trying
>> to clarify the design).
>>
>> For the design option 2, binding resource dependencies to each entity and
>> property, it is easy to understand (analogous to the relational database)
>> but hard to specify (e.g., IANA registry). Fortunately, authors already
>> have a proposal about the IANA registry design of design option 2, which
>> requires three new registries for entity domain types, properties, and
>> resource types.
>>
>>
>>
>> But we still need to make the final decision before we move forward.
>>
>>
>>
>> Hi Sabine,
>>
>>
>>
>> You mentioned that you still had some questions for the design option 2.
>> Could you post them here? I started to revise the document based on the
>> design option 2, but have not merged it to the latest revision. I hope our
>> co-authors can agree on a design at least before we moving to the document
>> revising for WGLC.
>>
>>
>>
>> There are some materials talking about two design options:
>>
>>
>>
>> [1]
>> https://datatracker.ietf.org/meeting/104/materials/slides-104-alto-unified-properties-for-alto-01.pdf
>>
>> [2]
>> https://docs.google.com/presentation/d/1lCcLLbyKqZjGADxcHSorfADKx_CoG1fz_j6GBfPGZQY/edit?usp=sharing
>>
>>
>>
>> Best regards,
>>
>> Jensen
>>
>>
ALTO WG W. Roome
Internet-Draft S. Randriamasy
Intended status: Standards Track Nokia Bell Labs
Expires: October 20, 2019 Y. Yang
Yale University
J. Zhang
Tongji University
April 18, 2019
Unified Properties for the ALTO Protocol
draft-ietf-alto-unified-props-new-08
Abstract
This document extends the Application-Layer Traffic Optimization
(ALTO) Protocol [RFC7285] by generalizing the concept of "endpoint
properties" to domains of other entities, and by presenting those
properties as maps, similar to the network and cost maps in
[RFC7285].
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 20, 2019.
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Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Definitions and Concepts . . . . . . . . . . . . . . . . . . 5
2.1. Entity . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1. Entity Domain . . . . . . . . . . . . . . . . . . . . 6
2.1.2. Entity Identifier . . . . . . . . . . . . . . . . . . 7
2.1.3. Entity Property . . . . . . . . . . . . . . . . . . . 8
2.1.4. Hierarchy and Inheritance . . . . . . . . . . . . . . 9
2.2. Resource . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.1. Resource Type . . . . . . . . . . . . . . . . . . . . 9
2.2.2. Entities and Properties Mapping . . . . . . . . . . . 9
3. Entity Domain Types . . . . . . . . . . . . . . . . . . . . . 10
3.1. Internet Address Domain Types . . . . . . . . . . . . . . 10
3.1.1. IPv4 Domain . . . . . . . . . . . . . . . . . . . . . 10
3.1.2. IPv6 Domain . . . . . . . . . . . . . . . . . . . . . 11
3.1.3. Hierarchy and Inheritance of Internet Address Domains 11
3.2. PID Domain . . . . . . . . . . . . . . . . . . . . . . . 12
3.2.1. Entity Domain Type . . . . . . . . . . . . . . . . . 12
3.2.2. Domain-Specific Entity Identifiers . . . . . . . . . 12
3.2.3. Hierarchy and Inheritance . . . . . . . . . . . . . . 13
3.2.4. Relationship To Internet Addresses Domains . . . . . 13
3.3. Internet Address Properties vs. PID Properties . . . . . 13
4. Resource Types . . . . . . . . . . . . . . . . . . . . . . . 13
4.1. Network Map Resource . . . . . . . . . . . . . . . . . . 13
4.1.1. Resource Type . . . . . . . . . . . . . . . . . . . . 13
4.1.2. Media Type . . . . . . . . . . . . . . . . . . . . . 14
4.1.3. Entities and Properties Mapping . . . . . . . . . . . 14
4.2. Endpoint Property Resource . . . . . . . . . . . . . . . 14
4.2.1. Resource Type . . . . . . . . . . . . . . . . . . . . 14
4.2.2. Media Type . . . . . . . . . . . . . . . . . . . . . 14
4.2.3. Entities and Properties Mapping . . . . . . . . . . . 14
4.3. Property Map Resource . . . . . . . . . . . . . . . . . . 15
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4.3.1. Resource Type . . . . . . . . . . . . . . . . . . . . 15
4.3.2. Media Type . . . . . . . . . . . . . . . . . . . . . 15
4.3.3. Entities and Properties Mapping . . . . . . . . . . . 15
5. Property Map . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 15
5.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 15
5.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 15
5.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 15
5.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 16
6. Filtered Property Map . . . . . . . . . . . . . . . . . . . . 17
6.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 17
6.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 18
6.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 18
6.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 18
6.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 19
7. Impact on Legacy ALTO Servers and ALTO Clients . . . . . . . 20
7.1. Impact on Endpoint Property Service . . . . . . . . . . . 20
7.2. Impact on Resource-Specific Properties . . . . . . . . . 21
7.3. Impact on the pid Property . . . . . . . . . . . . . . . 21
7.4. Impact on Other Properties . . . . . . . . . . . . . . . 21
8. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.1. Network Map . . . . . . . . . . . . . . . . . . . . . . . 22
8.2. Property Definitions . . . . . . . . . . . . . . . . . . 22
8.3. Information Resource Directory (IRD) . . . . . . . . . . 23
8.4. Property Map Example . . . . . . . . . . . . . . . . . . 25
8.5. Filtered Property Map Example #1 . . . . . . . . . . . . 25
8.6. Filtered Property Map Example #2 . . . . . . . . . . . . 26
8.7. Filtered Property Map Example #3 . . . . . . . . . . . . 27
8.8. Filtered Property Map Example #4 . . . . . . . . . . . . 28
9. Security Considerations . . . . . . . . . . . . . . . . . . . 29
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
10.1. application/alto-* Media Types . . . . . . . . . . . . . 30
10.2. ALTO Entity Domain Type Registry . . . . . . . . . . . . 31
10.2.1. Consistency Procedure between ALTO Address Type
Registry and ALTO Entity Domain Registry . . . . . . 32
10.2.2. ALTO Entity Domain Registration Process . . . . . . 33
10.3. ALTO Entity Property Type Registry . . . . . . . . . . . 34
10.4. ALTO Resource Type Registry . . . . . . . . . . . . . . 35
10.5. Acknowledgments . . . . . . . . . . . . . . . . . . . . 35
11. Normative References . . . . . . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37
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1. Introduction
The ALTO protocol [RFC7285] introduces the concept of "properties"
attached to "endpoint addresses", and defines the Endpoint Property
Service (EPS) to allow ALTO clients to retrieve those properties.
While useful, the EPS, as defined in [RFC7285], has at least two
limitations.
First, it allows properties to be associated with only a particular
domain of entities, namely individual IP addresses. It is reasonable
to think that collections of endpoints, as defined by CIDRs [RFC4632]
or PIDs, may also have properties. Since the EPS cannot be extended
to new entity domains, new services, with new request and response
messages, would have to be defined for new entity domains.
Second, the EPS is only defined as a POST-mode service. Clients must
request the properties for an explicit set of endpoint addresses. By
contrast, [RFC7285] defines a GET-mode cost map resource which
returns all available costs, so a client can get a full set of costs
once, and then processes costs lookups without querying the ALTO
server. [RFC7285] does not define an equivalent service for endpoint
properties. At first a map of endpoint properties might seem
impractical, because it could require enumerating the property value
for every possible endpoint. But in practice, it is highly unlikely
that properties will be defined for every endpoint address. It is
much more likely that properties may be defined for only a subset of
endpoint addresses, and the specification of properties uses an
aggregation representation to allow enumeration. This is
particularly true if blocks of endpoint addresses with a common
prefix (e.g., a CIDR) have the same value for a property. Entities
in other domains may very well allow aggregated representation and
hence be enumerable as well.
This document specifies a new approach for defining and retrieving
ALTO properties to address the two limitations. Specifically, this
document addresses the first limitation by introducing a generic
concept called ALTO Entity Domains, where an entity is a
generalization of an endpoint to also represent, a PID, a network
element, or a cell in a cellular network, etc. As a consequence,
ALTO Entity Domains defined in this document are a super-set of ALTO
Address Types defined in [RFC7285]. Their exact relationship is
specified in Section 10.2.1.
Entity domains and property names are extensible. New entity domains
can be defined without revising the messages defined in this
document, in the same way that new cost metrics and new endpoint
properties can be defined without revising the messages defined in
[RFC7285].
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Additional, this document addresses the second limitation by defining
two new types of resources, namely Property Map (see Section 5) and
Filtered Property Map (see Section 6). The former is a GET-mode
resource which returns the property values for all entities in a
domain, and is analogous to a network map or a cost map in [RFC7285].
The latter is a POST-mode resource which returns the values for a set
of properties and entities requested by the client, and is analogous
to a filtered network map or a filtered cost map.
This document subsumes the Endpoint Property Service defined in
[RFC7285], although that service may be retained for legacy clients
(see Section 7).
2. Definitions and Concepts
2.1. Entity
The entity concept generalizes the concept of the endpoint defined in
Section 2.1 of [RFC7285]. An entity is an object that can be an
endpoint and is identified by its network address, but can also be an
object that has a defined mapping to a set of one or more network
addresses or is even not related to any network address.
Examples of eligible entities are:
o a PID, defined in [RFC7285], that has a provider defined human
readable abstract identifier defined by a ALTO network map, which
maps a PID to a set of ipv4 and ipv6 addresses;
o an autonomous system (AS), that has an AS number (ASN) as its
identifier and maps to a set of ipv4 and ipv6 addresses;
o a region representing a country, that is identified by its country
code defined by ISO 3166 and maps to a set of cellular addresses;
o a TCP/IP network flow, that has a server defined identifier
consisting of the defining TCP/IP 5-Tuple, , which is an example
that all endpoints are entities while not all entities are
endpoints;
o a routing element, that is specified in [RFC7921] and includes
routing capability information;
o an abstract network element, that has a server defined identifier
and represents a network node, link or their aggregation.
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2.1.1. Entity Domain
Each entity MUST belong to one and only one entity domain, where an
entity domain is defined as a set of entities. An entity domain can
be a global entity domain; this document defines two global entity
domains, for two Internet address domains (see Section 3.1). An
entity domain can also be defined by an ALTO resource; this document
defines PID entity domains to be derived from ALTO network maps (see
Section 3.2). Future documents can define additional entity domains
to satisfy their additional requirements such as cellular network
information and routing capability exposure. But they are not in the
scope of this document.
2.1.1.1. Entity Domain Type
An entity domain has a type, which is defined by a string that MUST
be no more than 64 characters, and MUST NOT contain characters other
than US-ASCII alphanumeric characters (U+0030-U+0039, U+0041-U+005A,
and U+0061-U+007A), hyphen ("-", U+002D), and low line ("_", U+005F).
For example, the strings "ipv4", "ipv6", and "pid" are valid entity
domain types.
The type EntityDomainType is used in this document to denote a JSON
string confirming to the preceding requirement.
An entity domain type defines the semantics of a type of entity
domains. Each entity domain type MUST be registered with the IANA.
The format of the entity identifiers (see Section 2.1.2) in that type
of entity domains, as well as any hierarchical or inheritance rules
(see Section 2.1.4) for those entities, MUST be specified at the same
time.
2.1.1.2. Entity Domain Name
Each entity domain is identified by an entity domain name, a string
of the following format:
EntityDomainName ::= [ ResourceID '.' ] EntityDomainType
This document distinguish two types of entity domains: global entity
domains and resource-specific entity domains. Their entity domain
names are derived as follows.
Each entity domain type may have a global entity domain. For a
global entity domain (i.e., not resource-specific), its entity domain
name is an EntityDomainType typed string. For example, the "ipv4"
and "ipv6" entity domain types identify two Internet address entity
domains (see Section 3.1).
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A resource-specific entity domain is identified by an entity domain
name derived as follows. It MUST start with a resource ID using the
ResourceID type defined in [RFC7285], followed by the "." separator
(U+002E), followed by an EntityDomainType typed string. Hence, there
can be as many entity domains as the number of ALTO information
resources for each entity domain type. For example, if an ALTO
server provides two network maps "net-map-1" and "net-map-2", they
can define two different "pid" domains identified by "net-map-1.pid"
and "net-map-2.pid" respectively.
Note that the "." separator is not allowed in EntityDomainType and
hence there is no ambiguity on whether an entity domain name refers
to a global entity domain or a resource specific entity domain.
For an EntityDomainType which allows resource-specific entity
domains, the valid type(s) resources MUST be specified.
2.1.2. Entity Identifier
Entities in an entity domain are identified by entity identifiers
(EntityID) of the following format:
EntityID ::= EntityDomainName ':' DomainTypeSpecificEntityID
Examples from the Internet address entity domains include individual
IP addresses such as "ipv4:192.0.2.14" and "ipv6:2001:db8::12", as
well as address blocks such as "ipv4:192.0.2.0/26" and
"ipv6:2001:db8::1/48".
The format of the second part of an entity identifier depends on the
entity domain type, and MUST be specified when registering a new
entity domain type. Identifiers MAY be hierarchical, and properties
MAY be inherited based on that hierarchy. Again, the rules defining
any hierarchy or inheritance MUST be defined when the entity domain
type is registered.
The type EntityID is used in this document to denote a JSON string
representing an entity identifier in this format.
Note that two entity identifiers with different textual
representations may refer to the same entity, for a given entity
domain. For example, the strings "ipv6:2001:db8::1" and
"ipv6:2001:db8:0:0:0:0:0:1" refer to the same entity in the "ipv6"
entity domain.
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2.1.3. Entity Property
An entity property defines a property of an entity. It is similar to
the endpoint property defined by Section 7.1 of [RFC7285], but can be
general besides network-aware.
For example, an "ipv4" entity may have a property whose value is an
Autonomous System (AS) number indicating the AS which this IPv4
address is owned by.
2.1.3.1. Entity Property Type
Each entity property has a type to indicate the encoding and the
semantics of the value of this entity property. The type
EntityPropertyType is used in this document to indicate a string
denoting an entity property type. The string MUST be no more than 32
characters, and it MUST NOT contain characters other than US-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
the low line ('_', U+005F).
Each entity property type MUST be registered with the IANA. The
intended semantics of the entity property type MUST be specified at
the same time.
To distinguish with the endpoint property type, the entity property
type has the following features.
o Some entity property types may be applicable to entities in only
particular types of entity domains, not all. For example, the
"pid" property is not applicable to entities in a "pid" typed
entity domain, but is applicable to entities in the "ipv4" or
"ipv6" domains.
o The intended semantics of the value of a entity property may also
depend on the the entity domain type of this entity. For example,
suppose that the "geo-location" property is defined as the
coordinates of a point, encoded as (say) "latitude longitude
[altitude]." When applied to an entity that represents a specific
host computer, identified by an address in the "ipv4" or "ipv6"
entity domain, the property defines the host's location. However,
when applied to an entity in a "pid" domain, the property would
indicate the location of the center of all hosts in this "pid"
entity.
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2.1.3.2. Entity Property Name
Each entity property is identified by an entity property name, which
is a string of the following format:
EntityPropertyName ::= [ ResourceID '.' ] EntityPropertyType
Similar to the endpoint property type defined in Section 10.8 of
[RFC7285], each entity property may be defined by either the property
map itself (self-defined) or some other specific resource (resource-
specific).
The entity property name of a self-defined entity property is an
EntityPropertyType typed string. For example, the "asn" property of
an "ipv4" entity indicates the AS number of the AS which this IPv4
address is owned by.
The entity property name of a resource-specific entity property
starts with a string of the type ResourceID defined in [RFC7285],
followed by the "." separator (U+002E) and a EntityDomainType typed
string. For example, the "pid" properties of an "ipv4" entity
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.
2.1.4. Hierarchy and Inheritance
Entities in a given domain MAY form a hierarchy based on entity
identifiers, and introducing hierarchy allows the introduction of
inheritance. Each entity domain type MUST define its own hierarchy
and inheritance rules when registered. The hierarchy and inheritance
rule makes it possible for an entity to inherit a property value from
another entity in the same domain.
2.2. Resource
A resource indicates an ALTO information resource in this document.
2.2.1. Resource Type
Each resource has a type identified by a JSON string, which aliases
to a media type of an ALTO information resource.
2.2.2. Entities and Properties Mapping
Each type of resource MAY defines several entity domains in some
entity domain types. For example, a network map resource defines a
"pid" domain, a "ipv4" domain and a "ipv6" domain (which may be
empty).
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For each entity domain defined by a resource, this resource MAY also
provide a properties mapping function, which maps each entity in this
entity domain to a JSON object including several entity properties.
For example, a network map resource can map an "ipv4" entity to its
"pid" property.
Each resource type MUST be registered with the IANA. The aliased
media type, the supported entity domain types, as well as properties
mapping functions of each types of entity domains, MUST be specified
at the same time.
3. Entity Domain Types
This document defines three entity domain types. The definition of
each entity domain type below includes the following: (1) entity
domain type name, (2) entity domain-specific entity identifiers, and
(3) hierarchy and inheritance semantics. Since a global entity
domain type defines a single global entity domain, we say entity
domain instead of entity domain type.
3.1. Internet Address Domain Types
The document defines two entity domain types (IPv4 and IPv6) for
Internet addresses. Both types are global entity domain types and
hence define a corresponding global entity domain as well. Since the
two domains use the same hierarchy and inheritance semantics, we
define the semantics together, instead of repeating for each.
3.1.1. IPv4 Domain
3.1.1.1. Entity Domain Type
ipv4
3.1.1.2. Domain-Specific Entity Identifiers
Individual addresses are strings as specified by the IPv4Addresses
rule of Section 3.2.2 of [RFC3986]; blocks of addresses are prefix-
match strings as specified in Section 3.1 of [RFC4632]. For the
purpose of defining properties, an individual Internet address and
the corresponding full-length prefix are considered aliases for the
same entity. Thus "ipv4:192.0.2.0" and "ipv4:192.0.2.0/32" are
equivalent.
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3.1.2. IPv6 Domain
3.1.2.1. Entity Domain Type
ipv6
3.1.2.2. Domain-Specific Entity Identifiers
Individual addresses are strings as specified by Section 4 of
[RFC5952]; blocks of addresses are prefix-match strings as specified
in Section 7 of [RFC5952]. For the purpose of defining properties,
an individual Internet address and the corresponding 128-bit prefix
are considered aliases for the same entity. That is,
"ipv6:2001:db8::1" and "ipv6:2001:db8::1/128" are equivalent, and
have the same set of properties.
3.1.3. Hierarchy and Inheritance of Internet Address Domains
Both Internet address domains allow property values to be inherited.
Specifically, if a property P is not defined for a specific Internet
address I, but P is defined for some block C which prefix-matches I,
then the address I inherits the value of P defined for block C. If
more than one such block defines a value for P, I inherits the value
of P in the block with the longest prefix. It is important to notice
that this longest prefix rule will ensure no multiple inheritance,
and hence no ambiguity.
Address blocks can also inherit properties: if a property P is not
defined for a block C, but is defined for some block C' which covers
all IP addresses in C, and C' has a shorter mask than C, then block C
inherits the property from C'. If there are several such blocks C',
C inherits from the block with the longest prefix.
As an example, suppose that a server defines a property P for the
following entities:
ipv4:192.0.2.0/26: P=v1
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.
Then the following entities have the indicated values:
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ipv4:192.0.2.0: P=v4
ipv4:192.0.2.1: P=v3
ipv4:192.0.2.16: P=v1
ipv4:192.0.2.32: P=v1
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.
An ALTO server MAY explicitly indicate a property as not having a
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
"undefined". To indicate "no value", a server MAY perform different
behaviours:
o If that entity would inherit a value for that property, then the
ALTO server MUST return a "null" value for that property. In this
case, the ALTO client MUST recognize a "null" value as "no value"
and "do not apply the inheritance rules for this property."
o If the entity would not inherit a value, then the ALTO server MAY
return "null" or just omit the property. In this case, the ALTO
client cannot infer the value for this property of this entity
from the Inheritance rules. So the client MUST interpret that
this property has no value.
If the ALTO server does not define any properties for an entity, then
the server MAY omit that entity from the response.
3.2. PID Domain
The PID domain associates property values with the PIDs in a network
map. Accordingly, this entity domain always depends on a network
map.
3.2.1. Entity Domain Type
pid
3.2.2. Domain-Specific Entity Identifiers
The entity identifiers are the PID names of the associated network
map.
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3.2.3. Hierarchy and Inheritance
There is no hierarchy or inheritance for properties associated with
PIDs.
3.2.4. Relationship To Internet Addresses Domains
The PID domain and the Internet address domains are completely
independent; the properties associated with a PID have no relation to
the properties associated with the prefixes or endpoint addresses in
that PID. An ALTO server MAY choose to assign some or all properties
of a PID to the prefixes in that PID.
For example, suppose "PID1" consists of the prefix
"ipv4:192.0.2.0/24", and has the property "P" with value "v1". The
Internet address entities "ipv4:192.0.2.0" and "ipv4:192.0.2.0/24",
in the IPv4 domain MAY have a value for the property "P", and if they
do, it is not necessarily "v1".
3.3. Internet Address Properties vs. PID Properties
Because the Internet address and PID domains are completely separate,
the question may arise as to which entity domain is the best for a
property. In general, the Internet address domains are RECOMMENDED
for properties that are closely related to the Internet address, or
are associated with, and inherited through, blocks of addresses.
The PID domain is RECOMMENDED for properties that arise from the
definition of the PID, rather than from the Internet address prefixes
in that PID.
For example, because Internet addresses are allocated to service
providers by blocks of prefixes, an "ISP" property would be best
associated with the Internet address domain. On the other hand, a
property that explains why a PID was formed, or how it relates a
provider's network, would best be associated with the PID domain.
4. Resource Types
4.1. Network Map Resource
4.1.1. Resource Type
networkmap
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4.1.2. Media Type
application/alto-networkmap+json
4.1.3. Entities and Properties Mapping
An "networkmap" typed resource defines a "pid" domain, an "ipv4"
domain and an "ipv6" domain by follows:
o The defined "pid" domain includes all PIDs in keys of the
"network-map" object.
o The defined "ipv4" domain includes all IPv4 addresses appearing in
the "ipv4" field of the endpoint address group of each PID.
o The defined "ipv6" domain includes all IPv6 addresses appearing in
the "ipv6" field of the endpoint address group of each PID.
For each of the preceding entity domains, an "networkmap" typed
resource provides the properties mapping as follows:
ipv4 -> pid: An "networkmap" typed resource can map an "ipv4" entity
to a "pid" property whose value is a PID defined by this
"networkmap" resource and including the IPv4 address of this
entity.
ipv6 -> pid: An "networkmap" typed resource can map an "ipv6" entity
to a "pid" property whose value is a PID defined by this
"networkmap" resource and including the IPv6 address of this
entity.
4.2. Endpoint Property Resource
4.2.1. Resource Type
endpointprop
4.2.2. Media Type
application/alto-endpointprop+json
4.2.3. Entities and Properties Mapping
TBD.
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4.3. Property Map Resource
4.3.1. Resource Type
propmap
4.3.2. Media Type
application/alto-propmap+json
4.3.3. Entities and Properties Mapping
TODO: property map is special and should be able to provide any
mapping.
5. Property Map
A property map returns the properties defined for all entities in one
or more domains, e.g., the "location" property of entities in "pid"
domain, and the "ASN" property of entities in "ipv4" and "ipv6"
domains.
Section 8.4 gives an example of a property map request and its
response.
5.1. Media Type
The media type of a property map is "application/alto-propmap+json".
5.2. HTTP Method
The property map is requested using the HTTP GET method.
5.3. Accept Input Parameters
None.
5.4. Capabilities
The capabilities are defined by an object of type
PropertyMapCapabilities:
object {
EntityDomainName entity-domains<1..*>;
EntityPropertyName properties<1..*>;
} PropertyMapCapabilities;
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where "entity-domains" is an array specifying the entity domains, and
"properties" is an array specifying the property names returned for
entities in those domains. The semantics is that this property map
provides all property types generated by the cross product of
"entity-domains" and "properties". If a property in "properties" is
NOT supported by a domain in "entity-domains", the server can declare
different property maps to conform to the semantics.
For example, the capability {"entity-domains": ["ipv4", "ipv6"],
"properties": ["pid"]} means the property map provides both property
types "ipv4:pid" and "ipv6:pid".
5.5. Uses
The "uses" field of a property map resource in an IRD entry specifies
dependencies as discussed in Section 2.7. It is an array of the
resource ID(s) of the resource(s) that properties of entities in
domains specified in "entity-domains" depend on.
In a single property map, every property value of every entity
depends on the same array of resources. Thus, if properties
depending on different resources arrays would be provided, they MUST
be split into different property maps.
Note that according to [RFC7285], a legacy ALTO server with two
network maps, with resource IDs "net1" and "net2", could offer a
single Endpoint Property Service for the two properties "net1.pid"
and "net2.pid". An ALTO server which supports the property map
resource defined in this document, would, instead, offer two
different property maps for the "pid" property, one depending on
"net1", and the other on "net2".
5.6. Response
If the entity domains in this property map depend on other resources,
the "dependent-vtags" field in the "meta" field of the response MUST
be an array that includes the version tags of those resources, and
the order MUST be consistent with the "uses" field of this property
map resource. The data component of a property map response is named
"property-map", which is a JSON object of type PropertyMapData,
where:
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object {
PropertyMapData property-map;
} InfoResourceProperties : ResponseEntityBase;
object-map {
EntityID -> EntityProps;
} PropertyMapData;
object {
EntityPropertyName -> JSONValue;
} EntityProps;
The ResponseEntityBase type is defined in Section 8.4 of [RFC7285].
Specifically, a PropertyMapData object has one member for each entity
in the property map. The entity's properties are encoded in the
corresponding EntityProps object. EntityProps encodes one name/value
pair for each property, where the property names are encoded as
strings of type PropertyName. A protocol implementation SHOULD
assume that the property value is either a JSONString or a JSON
"null" value, and fail to parse if it is not, unless the
implementation is using an extension to this document that indicates
when and how property values of other data types are signaled.
For each entity in the Property Map, the ALTO server returns the
value defined for each of the properties specified in this resource's
"capabilities" list. For efficiency, the ALTO server SHOULD omit
property values that are inherited rather than explicitly defined; if
a client needs inherited values, the client SHOULD use the entity
domain's inheritance rules to deduce those values.
6. Filtered Property Map
A filtered property map returns the values of a set of properties for
a set of entities selected by the client.
Section 8.5, Section 8.6, Section 8.7 and Section 8.8 give examples
of filtered property map requests and responses.
6.1. Media Type
The media type of a property map resource is "application/alto-
propmap+json".
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6.2. HTTP Method
The filtered property map is requested using the HTTP POST method.
6.3. Accept Input Parameters
The input parameters for a filtered property map request are supplied
in the entity body of the POST request. This document specifies the
input parameters with a data format indicated by the media type
"application/alto-propmapparams+json", which is a JSON object of type
ReqFilteredPropertyMap:
object {
EntityID entities<1..*>;
EntityPropertyName properties<1..*>;
} ReqFilteredPropertyMap;
with fields:
entities: List of entity identifiers for which the specified
properties are to be returned. The ALTO server MUST interpret
entries appearing multiple times as if they appeared only once.
The domain of each entity MUST be included in the list of entity
domains in this resource's "capabilities" field (see Section 6.4).
properties: List of properties to be returned for each entity. Each
specified property MUST be included in the list of properties in
this resource's "capabilities" field (see Section 6.4). The ALTO
server MUST interpret entries appearing multiple times as if they
appeared only once.
Note that the "entities" and "properties" fields MUST have at
least one entry each.
6.4. Capabilities
The capabilities are defined by an object of type
PropertyMapCapabilities, as defined in Section 5.4.
6.5. Uses
The "uses" field of a filtered property map is an array with the
resource ID(s) of resource(s) that each domain in "entity-domains"
depends on, in order to provide the properties specified in the
"properties" capability. The same "uses" rule as defined by the
property map resource applies (see Section 5.5).
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6.6. Response
The response MUST indicate an error, using ALTO protocol error
handling, as defined in Section 8.5 of [RFC7285], if the request is
invalid.
Specifically, a filtered property map request can be invalid as
follows:
o An entity identifier in "entities" in the request is invalid if:
* The domain of this entity is not defined in the "entity-
domains" capability of this resource in the IRD;
* The entity identifier is an invalid identifier in the entity
domain.
A valid entity identifier is never an error, even if this filtered
property map resource does not define any properties for it.
If an entity identifier in "entities" in the request is invalid,
the ALTO server MUST return an "E_INVALID_FIELD_VALUE" error
defined in Section 8.5.2 of [RFC7285], and the "value" field of
the error message SHOULD indicate this entity identifier.
o A property name in "properties" in the request is invalid if this
property name is not defined in the "properties" capability of
this resource in the IRD.
It is not an error that a filtered property map resource does not
define a requested property's value for a particular entity. In
this case, the ALTO server MUST omit that property from the
response for that endpoint.
If a property name in "properties" in the request is invalid, the
ALTO server MUST return an "E_INVALID_FIELD_VALUE" error defined
in Section 8.5.2 of [RFC7285]. The "value" field of the error
message SHOULD indicate the property name.
The response to a valid request is the same as for the Property Map
(see Section 5.6), except that:
o The "dependent-vtags" field in its "meta" field only includes the
version tags of resources on which the requested properties of the
entity domains depend, and the order MUST be consistent with the
"uses" field of this filtered property map resource.
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o It only includes the entities and properties requested by the
client. If an entity in the request is an identifier block (e.g.,
an "ipv4" or "ipv6" entity), the response MUST cover properties
for all identifiers in this block.
It is important that the filtered property map response MUST include
all inherited property values for the requested entities and all the
entities which are able to inherit property values from them. To
achieve this goal, the ALTO server MAY follow three rules:
o If a property for a requested entity is inherited from another
entity not included in the request, the response SHOULD include
this property for the requested entity. For example, A full
property map may skip a property P for an entity A (e.g.,
ipv4:192.0.2.0/31) if P can be derived using inheritance from
another entity B (e.g., ipv4:192.0.2.0/30). A filtered property
map request may include only A but not B. In such a case, the
property P SHOULD be included in the response for A.
o If there are entities covered by a requested entity but having
different values for the requested properties, the response SHOULD
include all those entities and the different property values for
them. For example, considering a request for property P of entity
A (e.g., ipv4:192.0.2.0/31), if P has value v1 for
A1=ipv4:192.0.2.0/32 and v2 for A2=ipv4:192.0.2.1/32, then, the
response SHOULD include A1 and A2.
o If an entity in the response is already covered by some other
entities in the same response, it SHOULD be removed from the
response for compactness. For example, in the previous example,
the entity A=ipv4:192.0.2.0/31 SHOULD be removed because A1 and A2
cover all the addresses in A.
An ALTO client should be aware that the entities in the response MAY
be different from the entities in its request.
7. Impact on Legacy ALTO Servers and ALTO Clients
7.1. Impact on Endpoint Property Service
Since the property map and the filtered property map defined in this
document provide the functionality of the Endpoint Property Service
(EPS) defined in Section 11.4 of [RFC7285], it is RECOMMENDED that
the EPS be deprecated in favor of Property Map and Filtered Property
Map. However, ALTO servers MAY provide an EPS for the benefit of
legacy clients.
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7.2. Impact on Resource-Specific Properties
Section 10.8 of [RFC7285] defines two categories of endpoint
properties: "resource-specific" and "global". Resource-specific
property names are prefixed with the ID of the resource they depend
upon, while global property names have no such prefix. The property
map and the filtered property map defined in this document do not
distinguish between those two types of properties. Instead, if there
is a dependency, it is indicated by the "uses" capability of a
property map, and is shared by all properties and entity domains in
that map. Accordingly, it is RECOMMENDED that resource-specific
endpoint properties be deprecated, and no new resource-specific
endpoint properties be defined.
7.3. Impact on the pid Property
Section 7.1.1 of [RFC7285] defines the resource-specific endpoint
property name "pid", whose value is the name of the PID containing
that endpoint. For compatibility with legacy clients, an ALTO server
which provides the "pid" property via the EPS MUST use that
definition, and that syntax.
However, when used with property maps, this document amends the
definition of the "pid" property as follows.
First, the name of the property is simply "pid"; the name is not
prefixed with the resource ID of a network map. The "uses"
capability of the property map indicates the associated network map.
This implies that a property map can only return the "pid" property
for one network map; if an ALTO server provides several network maps,
it MUST provide a Property Map for each of the network maps.
Second, a client MAY request the "pid" property for a block of
Internet addresses. An ALTO server determines the value of "pid" for
an address block C as the rules defined in Section 6.6.
Note that although an ALTO server MAY provide a GET-mode property map
which returns the entire map for the "pid" property, there is no need
to do so, because that map is simply the inverse of the network map.
7.4. Impact on Other Properties
In general, there should be little or no impact on other previously
defined properties. The only consideration is that properties can
now be defined on blocks of identifiers, rather than just individual
identifiers, which might change the semantics of a property.
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8. Examples
8.1. Network Map
The examples in this section use a very simple default network map:
defaultpid: ipv4:0.0.0.0/0 ipv6:::0/0
pid1: ipv4:192.0.2.0/25
pid2: ipv4:192.0.2.0/28 ipv4:192.0.2.16/28
pid3: ipv4:192.0.3.0/28
pid4: ipv4:192.0.3.16/28
Figure 3: Example Network Map
8.2. Property Definitions
Beyond "pid", the examples in this section use four additional
properties for Internet address domains, "ISP", "ASN", "country" and
"state", with the following values:
ISP ASN country state
ipv4:192.0.2.0/23: BitsRus - us -
ipv4:192.0.2.0/28: - 12345 - NJ
ipv4:192.0.2.16/28: - 12345 - CT
ipv4:192.0.2.0: - - - PA
ipv4:192.0.3.0/28: - 12346 - TX
ipv4:192.0.3.16/28: - 12346 - MN
Figure 4: Example Property Values for Internet Address Domains
And the examples in this section use the property "region" for PID
domain with the following values:
region
pid:defaultpid: -
pid:pid1: west
pid:pid2: east
pid:pid3: south
pid:pid4: north
Figure 5: Example Property Values for PID Domain
Note that "-" means the value of the property for the entity is
"undefined". So the entity would inherit a value for this property
by the inheritance rule if possible. For example, the value of the
"ISP" property for "ipv4:192.0.2.0" is "BitsRus" because of
"ipv4:192.0.2.0/24". But the "region" property for "pid:defaultpid"
has no value because no entity from which it can inherit.
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8.3. Information Resource Directory (IRD)
The following IRD defines the relevant resources of the ALTO server.
It provides two property maps, one for the "ISP" and "ASN"
properties, and another for the "country" and "state" properties.
The server could have provided a single property map for all four
properties, but did not, presumably because the organization that
runs the ALTO server believes any given client is not interested in
all four properties.
The server provides two filtered property maps. The first returns
all four properties, and the second just returns the "pid" property
for the default network map.
The filtered property maps for the "ISP", "ASN", "country" and
"state" properties do not depend on the default network map (it does
not have a "uses" capability), because the definitions of those
properties do not depend on the default network map. The Filtered
Property Map for the "pid" property does have a "uses" capability for
the default network map, because that defines the values of the "pid"
property.
Note that for legacy clients, the ALTO server provides an Endpoint
Property Service for the "pid" property for the default network map.
"meta" : {
...
"default-alto-network-map" : "default-network-map"
},
"resources" : {
"default-network-map" : {
"uri" : "http://alto.example.com/networkmap";,
"media-type" : "application/alto-networkmap+json"
},
.... property map resources ....
"country-state-property-map" : {
"uri" : "http://alto.example.com/propmap/full/inet-cs";,
"media-type" : "application/alto-propmap+json",
"capabilities" : {
"entity-domains": [ "ipv4", "ipv6" ],
"properties" : [ "country", "state" ]
}
},
"isp-asn-property-map" : {
"uri" : "http://alto.example.com/propmap/full/inet-ia";,
"media-type" : "application/alto-propmap+json",
"capabilities" : {
"entity-domains": [ "ipv4", "ipv6" ],
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"properties" : [ "ISP", "ASN" ]
}
},
"iacs-property-map" : {
"uri" : "http://alto.example.com/propmap/lookup/inet-iacs";,
"media-type" : "application/alto-propmap+json",
"accepts" : "application/alto-propmapparams+json",
"capabilities" : {
"entity-domains": [ "ipv4", "ipv6" ],
"properties" : [ "ISP", "ASN", "country", "state" ]
}
},
"pid-property-map" : {
"uri" : "http://alto.example.com/propmap/lookup/pid";,
"media-type" : "application/alto-propmap+json",
"accepts" : "application/alto-propmapparams+json",
"uses" : [ "default-network-map" ]
"capabilities" : {
"entity-domains" : [ "ipv4", "ipv6" ],
"properties" : [ "default-network-map.pid" ]
}
},
"region-property-map": {
"uri": "http://alto.exmaple.com/propmap/region";,
"media-type": "application/alto-propmap+json",
"accepts": "application/alto-propmapparams+json",
"uses" : [ "default-network-map" ],
"capabilities": {
"domain-types": [ "default-network-map.pid" ],
"properties": [ "region" ]
}
},
"legacy-pid-property" : {
"uri" : "http://alto.example.com/legacy/eps-pid";,
"media-type" : "application/alto-endpointprop+json",
"accepts" : "application/alto-endpointpropparams+json",
"capabilities" : {
"properties" : [ "default-network-map.pid" ]
}
}
}
Figure 6: Example IRD
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8.4. Property Map Example
The following example uses the properties and IRD defined above to
retrieve a Property Map for entities with the "ISP" and "ASN"
properties.
Note that, to be compact, the response does not includes the entity
"ipv4:192.0.2.0", because values of all those properties for this
entity are inherited from other entities.
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 have the same value of the "ASN" property. The same rule
applies to the entities "ipv4:192.0.3.0/28" and "ipv4:192.0.3.0/28".
Both of "ipv4:192.0.2.0/27" and "ipv4:192.0.3.0/27" omit the value
for the "ISP" property, because it is inherited from
"ipv4:192.0.2.0/23".
GET /propmap/full/inet-ia HTTP/1.1
Host: alto.example.com
Accept: application/alto-propmap+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: ###
Content-Type: application/alto-propmap+json
{
"property-map": {
"ipv4:192.0.2.0/23": {"ISP": "BitsRus"},
"ipv4:192.0.2.0/27": {"ASN": "12345"},
"ipv4:192.0.3.0/27": {"ASN": "12346"}
}
}
8.5. Filtered Property Map Example #1
The following example uses the filtered property map resource to
request the "ISP", "ASN" and "state" properties for several IPv4
addresses.
Note that the value of "state" for "ipv4:192.0.2.0" is the only
explicitly defined property; the other values are all derived by the
inheritance rules for Internet address entities.
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POST /propmap/lookup/inet-iacs HTTP/1.1
Host: alto.example.com
Accept: application/alto-propmap+json,application/alto-error+json
Content-Length: ###
Content-Type: application/alto-propmapparams+json
{
"entities" : [ "ipv4:192.0.2.0",
"ipv4:192.0.2.1",
"ipv4:192.0.2.17" ],
"properties" : [ "ISP", "ASN", "state" ]
}
HTTP/1.1 200 OK
Content-Length: ###
Content-Type: application/alto-propmap+json
{
"property-map": {
"ipv4:192.0.2.0":
{"ISP": "BitsRus", "ASN": "12345", "state": "PA"},
"ipv4:192.0.2.1":
{"ISP": "BitsRus", "ASN": "12345", "state": "NJ"},
"ipv4:192.0.2.17":
{"ISP": "BitsRus", "ASN": "12345", "state": "CT"}
}
}
8.6. Filtered Property Map Example #2
The following example uses the filtered property map resource to
request the "ASN", "country" and "state" properties for several IPv4
prefixes.
Note that the property values for both entities "ipv4:192.0.2.0/26"
and "ipv4:192.0.3.0/26" are not explicitly defined. They are
inherited from the entity "ipv4:192.0.2.0/23".
Also note that some entities like "ipv4:192.0.2.0/28" and
"ipv4:192.0.2.16/28" in the response are not listed in the request
explicitly. The response includes them because they are refinements
of the requested entities and have different values for the requested
properties.
The entity "ipv4:192.0.4.0/26" is not included in the response,
because there are neither entities which it is inherited from, nor
entities inherited from it.
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POST /propmap/lookup/inet-iacs HTTP/1.1
Host: alto.example.com
Accept: application/alto-propmap+json,application/alto-error+json
Content-Length: ###
Content-Type: application/alto-propmapparams+json
{
"entities" : [ "ipv4:192.0.2.0/26",
"ipv4:192.0.3.0/26",
"ipv4:192.0.4.0/26" ],
"properties" : [ "ASN", "country", "state" ]
}
HTTP/1.1 200 OK
Content-Length: ###
Content-Type: application/alto-propmap+json
{
"property-map": {
"ipv4:192.0.2.0/26": {"country": "us"},
"ipv4:192.0.2.0/28": {"ASN": "12345",
"state": "NJ"},
"ipv4:192.0.2.16/28": {"ASN": "12345",
"state": "CT"},
"ipv4:192.0.2.0": {"state": "PA"},
"ipv4:192.0.3.0/26": {"country": "us"},
"ipv4:192.0.3.0/28": {"ASN": "12345",
"state": "TX"},
"ipv4:192.0.3.16/28": {"ASN": "12345",
"state": "MN"}
}
}
8.7. Filtered Property Map Example #3
The following example uses the filtered property map resource to
request the "pid" property for several IPv4 addresses and prefixes.
Note that the entity "ipv4:192.0.3.0/27" is redundant in the
response. Although it can inherit a value of "defaultpid" for the
"pid" property from the entity "ipv4:0.0.0.0/0", none of addresses in
it is in "defaultpid". Because blocks "ipv4:192.0.3.0/28" and
"ipv4:192.0.3.16/28" have already cover all addresses in that block.
So an ALTO server who wants a compact response can omit this entity.
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POST /propmap/lookup/pid HTTP/1.1
Host: alto.example.com
Accept: application/alto-propmap+json,application/alto-error+json
Content-Length: ###
Content-Type: application/alto-propmapparams+json
{
"entities" : [
"ipv4:192.0.2.128",
"ipv4:192.0.3.0/27" ],
"properties" : [ "default-network-map.pid" ]
}
HTTP/1.1 200 OK
Content-Length: ###
Content-Type: application/alto-propmap+json
{
"meta" : {
"dependent-vtags" : [
{"resource-id": "default-network-map",
"tag": "7915dc0290c2705481c491a2b4ffbec482b3cf62"}
]
},
"property-map": {
"ipv4:192.0.2.128": {"default-network-map.pid": "defaultpid"},
"ipv4:192.0.2.0/27": {"default-network-map.pid": "defaultpid"},
"ipv4:192.0.3.0/28": {"default-network-map.pid": "pid3"},
"ipv4:192.0.3.16/28": {"default-network-map.pid": "pid4"}
}
}
8.8. Filtered Property Map Example #4
The following example uses the filtered property map resource to
request the "region" property for several PIDs defined in "default-
network-map". The value of the "region" property for each PID is not
defined by "default-network-map", but the reason why the PID is
defined by the network operator.
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POST /propmap/lookup/region HTTP/1.1
Host: alto.example.com
Accept: application/alto-propmap+json,application/alto-error+json
Content-Length: ###
Content-Type: application/alto-propmapparams+json
{
"entities" : ["default-network-map.pid:pid1",
"default-network-map.pid:pid2"],
"properties" : [ "region" ]
}
HTTP/1.1 200 OK
Content-Length: ###
Content-Type: application/alto-propmap+json
{
"meta" : {
"dependent-vtags" : [
{"resource-id": "default-network-map",
"tag": "7915dc0290c2705481c491a2b4ffbec482b3cf62"}
]
},
"property-map": {
"default-network-map.pid:pid1": {
"region": "west"
},
"default-network-map.pid:pid2": {
"region": "east"
}
}
}
9. Security Considerations
Both Property Map and Filtered Property Map defined in this document
fit into the architecture of the ALTO base protocol, and hence the
Security Considerations (Section 15 of [RFC7285]) of the base
protocol fully apply: authenticity and integrity of ALTO information
(i.e., authenticity and integrity of Property Maps), potential
undesirable guidance from authenticated ALTO information (e.g.,
potentially imprecise or even wrong value of a property such as geo-
location), confidentiality of ALTO information (e.g., exposure of a
potentially sensitive entity property such as geo-location), privacy
for ALTO users, and availability of ALTO services should all be
considered.
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A particular fundamental security consideration when an ALTO server
provides a Property Map is to define precisely the policies on who
can access what properties for which entities. Security mechanisms
such as authentication and confidentiality mechanisms then should be
applied to enforce the policy. For example, a policy can be that a
property P can be accessed only by its owner (e.g., the customer who
is allocated a given IP address). Then, the ALTO server will need to
deploy corresponding mechanisms to realize the policy. The policy
may allow non-owners to access a coarse-grained value of the property
P. In such a case, the ALTO server may provide a different URI to
provide the information.
10. IANA Considerations
This document defines additional application/alto-* media types, and
extends the ALTO endpoint property registry.
10.1. application/alto-* Media Types
This document registers two additional ALTO media types, listed in
Table 1.
+--------------+--------------------------+------------------------+
| Type | Subtype | Specification |
+--------------+--------------------------+------------------------+
| application | alto-propmap+json | Section 5.1 |
| application | alto-propmapparams+json | Section 6.3 |
+--------------+--------------------------+------------------------+
Table 1: Additional ALTO Media Types.
Type name: application
Subtype name: This document registers multiple subtypes, as listed
in Table 1.
Required parameters: n/a
Optional parameters: n/a
Encoding considerations: Encoding considerations are identical to
those specified for the "application/json" media type. See
[RFC7159].
Security considerations: Security considerations related to the
generation and consumption of ALTO Protocol messages are discussed
in Section 15 of [RFC7285].
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Interoperability considerations: This document specifies formats of
conforming messages and the interpretation thereof.
Published specification: This document is the specification for
these media types; see Table 1 for the section documenting each
media type.
Applications that use this media type: ALTO servers and ALTO clients
either stand alone or are embedded within other applications.
Additional information:
Magic number(s): n/a
File extension(s): This document uses the mime type to refer to
protocol messages and thus does not require a file extension.
Macintosh file type code(s): n/a
Person & email address to contact for further information: See
Authors' Addresses section.
Intended usage: COMMON
Restrictions on usage: n/a
Author: See Authors' Addresses section.
Change controller: Internet Engineering Task Force
(mailto:[email protected]).
10.2. ALTO Entity Domain Type Registry
This document requests IANA to create and maintain the "ALTO Entity
Domain Type Registry", listed in Table 2.
+-------------+---------------------------+-------------------------+
| Identifier | Entity Identifier | Hierarchy & Inheritance |
| | Encoding | |
+-------------+---------------------------+-------------------------+
| ipv4 | See Section 3.1.1 | See Section 3.1.3 |
| ipv6 | See Section 3.1.2 | See Section 3.1.3 |
| pid | See Section 3.2 | None |
+-------------+---------------------------+-------------------------+
Table 2: ALTO Entity Domains.
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This registry serves two purposes. First, it ensures uniqueness of
identifiers referring to ALTO entity domains. Second, it states the
requirements for allocated entity domains.
10.2.1. Consistency Procedure between ALTO Address Type Registry and
ALTO Entity Domain Registry
One potential issue of introducing the "ALTO Entity Domain Registry"
is its relationship with the "ALTO Address Types Registry" already
defined in Section 14.4 of [RFC7285]. In particular, the entity
identifier of an entity domain registered in the "ALTO Entity Domain
Registry" MAY match an address type defined in "ALTO Address Type
Registry". It is necessary to precisely define and guarantee the
consistency between "ALTO Address Type Registry" and "ALTO Entity
Domain Registry".
We define that the ALTO Entity Domain Registry is consistent with
ALTO Address Type Registry if two conditions are satisfied:
o When an address type is already or able to be registered in the
ALTO Address Type Registry [RFC7285], the same identifier MUST be
used when a corresponding entity domain is registered in the ALTO
Entity Domain Registry.
o If an ALTO entity domain has the same identifier as an ALTO
address type, their addresses encoding MUST be compatible.
To achieve this consistency, the following items MUST be checked
before registering a new ALTO entity domain in a future document:
o Whether the ALTO Address Type Registry contains an address type
that can be used as an entity identifier for the candidate domain
identifier. This has been done for the identifiers "ipv4" and
"ipv6" in Table 2.
o Whether the candidate entity identifier of the entity domain is
able to be an endpoint address, as defined in Sections 2.1 and 2.2
of [RFC7285].
When a new ALTO entity domain is registered, the consistency with the
ALTO Address Type Registry MUST be ensured by the following
procedure:
o Test: Do corresponding entity identifiers match a known "network"
address type?
* If yes (e.g., cell, MAC or socket addresses):
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+ Test: Is such an address type present in the ALTO Address
Type Registry?
- If yes: Set the new ALTO entity domain identifier to be
the found ALTO address type identifier.
- If no: Define a new ALTO entity domain identifier and use
it to register a new address type in the ALTO Address
Type Registry following Section 14.4 of [RFC7285].
+ Use the new ALTO entity domain identifier to register a new
ALTO entity domain in the ALTO Entity Domain Registry
following Section 10.2.2 of this document.
* If no (e.g., pid name, ane name or country code): Proceed with
the ALTO Entity Domain registration as described in
Section 10.2.2.
10.2.2. ALTO Entity Domain Registration Process
New ALTO entity domains are assigned after IETF Review [RFC5226] to
ensure that proper documentation regarding the new ALTO entity
domains and their security considerations has been provided. RFCs
defining new entity domains SHOULD indicate how an entity in a
registered domain is encoded as an EntityId, and, if applicable, the
rules defining the entity hierarchy and property inheritance.
Updates and deletions of ALTO entity domains follow the same
procedure.
Registered ALTO entity domain identifiers MUST conform to the
syntactical requirements specified in Section 2.1.1.2. Identifiers
are to be recorded and displayed as strings.
Requests to the IANA to add a new value to the registry MUST include
the following information:
o Identifier: The name of the desired ALTO entity domain.
o Entity Identifier Encoding: The procedure for encoding the
identifier of an entity of the registered type as an EntityId (see
Section 2.1.2). If corresponding entity identifiers of an entity
domain match a known "network" address type, the Entity Identifier
Encoding of this domain identifier MUST include both Address
Encoding and Prefix Encoding of the same identifier registered in
the ALTO Address Type Registry [RFC7285]. For the purpose of
defining properties, an individual entity identifier and the
corresponding full-length prefix MUST be considered aliases for
the same entity.
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o Hierarchy: If the entities form a hierarchy, the procedure for
determining that hierarchy.
o Inheritance: If entities can inherit property values from other
entities, the procedure for determining that inheritance.
o Mapping to ALTO Address Type: A boolean value to indicate if the
entity domain can be mapped to the ALTO address type with the same
identifier.
o Security Considerations: In some usage scenarios, entity
identifiers carried in ALTO Protocol messages may reveal
information about an ALTO client or an ALTO service provider.
Applications and ALTO service providers using addresses of the
registered type should be made aware of how (or if) the addressing
scheme relates to private information and network proximity.
This specification requests registration of the identifiers "ipv4",
"ipv6" and "pid", as shown in Table 2.
10.3. ALTO Entity Property Type Registry
This document requests IANA to create and maintain the "ALTO Entity
Property Type Registry", listed in Table 3.
To distinguish with the "ALTO Endpoint Property Type Registry", each
entry in this registry is an ALTO entity property type defined in
Section 2.1.3.1. Thus, registered ALTO entity property type
identifier MUST conform to the syntactical requirements specified in
that section.
The initial registered ALTO entity property types are listed in
Table 3.
+------------+------------------+-----------------------------------+
| Identifier | Intended | Dependencies and Interpretation |
| | Semantics | |
+------------+------------------+-----------------------------------+
| ipv4:pid | PID for the IPv4 | application/alto-networkmap+json, |
| | entity | where the PID names are defined |
| ipv6:pid | PID for the IPv6 | application/alto-networkmap+json, |
| | entity | where the PID names are defined |
+------------+------------------+-----------------------------------+
Table 3: ALTO Entity Property Types.
Requests to the IANA to add a new value to the registry MUST include
the following information:
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o Identifier: The unique id for the desired ALTO entity property
type. The format MUST be as defined in Section 2.1.3.1 of this
document. It includes the information of the applied ALTO entity
domain and the property name.
o Intended Semantics: ALTO entity properties carry with them
semantics to guide their usage by ALTO clients. Hence, a document
defining a new type SHOULD provide guidance to both ALTO service
providers and applications utilizing ALTO clients as to how values
of the registered ALTO entity property should be interpreted.
o Dependencies and Interpretation: Dependent ALTO resources MAY be
required by ALTO clients to interpret ALTO entity properties.
Hence, a document defining a new type SHOULD provide a sequence of
media types in which the dependent ALTO resources are and the
guidance how ALTO clients use them to interpret the property.
This specification requests registration of the identifiers
"ipv4:pid" and "ipv6:pid", as shown in Table 3.
10.4. ALTO Resource Type Registry
The initial registered ALTO entity property types are listed in
Table 4.
+--------------+------------------------------------+---------------+
| Resource | Media Types | Entities and |
| Type | | Properties |
| | | Mapping |
+--------------+------------------------------------+---------------+
| networkmap | application/alto-networkmap+json | See |
| | | Section 4.1.3 |
| endpointprop | application/alto-endpointprop+json | See |
| | | Section 4.2.3 |
| propmap | application/alto-propmap+json | See |
| | | Section 4.3.3 |
+--------------+------------------------------------+---------------+
Table 4: ALTO Resource Types.
10.5. Acknowledgments
The authors would like to thank discussions with Kai Gao, Qiao Xiang,
Shawn Lin, Xin Wang, Danny Perez, and Vijay Gurbani. The authors
thank Dawn Chen (Tongji University), and Shenshen Chen (Tongji/Yale
University) for their contributions to earlier drafts.
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11. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing
(CIDR): The Internet Address Assignment and Aggregation
Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August
2006, <https://www.rfc-editor.org/info/rfc4632>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
Address Text Representation", RFC 5952,
DOI 10.17487/RFC5952, August 2010,
<https://www.rfc-editor.org/info/rfc5952>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
"Application-Layer Traffic Optimization (ALTO) Protocol",
RFC 7285, DOI 10.17487/RFC7285, September 2014,
<https://www.rfc-editor.org/info/rfc7285>.
[RFC7921] Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
Nadeau, "An Architecture for the Interface to the Routing
System", RFC 7921, DOI 10.17487/RFC7921, June 2016,
<https://www.rfc-editor.org/info/rfc7921>.
[RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
R., and K. Ma, "Content Delivery Network Interconnection
(CDNI) Request Routing: Footprint and Capabilities
Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
<https://www.rfc-editor.org/info/rfc8008>.
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Authors' Addresses
Wendy Roome
Nokia Bell Labs (Retired)
124 Burlington Rd
Murray Hill, NJ 07974
USA
Phone: +1-908-464-6975
Email: [email protected]
Sabine Randriamasy
Nokia Bell Labs
Route de Villejust
NOZAY 91460
FRANCE
Email: [email protected]
Y. Richard Yang
Yale University
51 Prospect Street
New Haven, CT 06511
USA
Phone: +1-203-432-6400
Email: [email protected]
Jingxuan Jensen Zhang
Tongji University
4800 Caoan Road
Shanghai 201804
China
Email: [email protected]
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