Internet DRAFT - draft-roome-alto-unified-props-new
draft-roome-alto-unified-props-new
ALTO WG W. Roome
Internet-Draft Nokia Bell Labs
Intended status: Standards Track R. Yang
Expires: January 4, 2018 Yale University
July 3, 2017
Extensible Property Maps for the ALTO Protocol
draft-roome-alto-unified-props-new-01
Abstract
This document extends the Application-Layer Traffic Optimization
(ALTO) Protocol [RFC7285] by generalizing the concept of "endpoint
properties" to other entity domains, and by presenting those
properties as maps, similar to the network and cost maps in ALTO.
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 http://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 January 4, 2018.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions and Concepts . . . . . . . . . . . . . . . . . . 4
2.1. Entity . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Domain . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Entity Address . . . . . . . . . . . . . . . . . . . . . 4
2.4. Domain Name . . . . . . . . . . . . . . . . . . . . . . . 5
2.5. Property Name . . . . . . . . . . . . . . . . . . . . . . 5
2.6. Property Value . . . . . . . . . . . . . . . . . . . . . 6
2.7. Hierarchy and Inheritance . . . . . . . . . . . . . . . . 6
2.8. Relationship to Network Maps . . . . . . . . . . . . . . 6
3. Entity Domains . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Internet Address Domains . . . . . . . . . . . . . . . . 7
3.1.1. IPv4 Domain . . . . . . . . . . . . . . . . . . . . . 7
3.1.2. IPv6 Domain . . . . . . . . . . . . . . . . . . . . . 8
3.1.3. Hierarchy and Inheritance of ipv4/ipv6 Domains . . . 8
3.1.4. Relationship to Network Maps . . . . . . . . . . . . 9
3.2. PID Domain . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.1. Domain Name . . . . . . . . . . . . . . . . . . . . . 10
3.2.2. Domain-Specific Entity Addresses . . . . . . . . . . 10
3.2.3. Hierarchy and Inheritance . . . . . . . . . . . . . . 10
3.2.4. Relationship To Internet Addresses Domains . . . . . 10
3.3. Internet Address Properties vs. PID Properties . . . . . 10
3.4. ANE Domain . . . . . . . . . . . . . . . . . . . . . . . 11
3.4.1. Domain Name . . . . . . . . . . . . . . . . . . . . . 11
3.4.2. Domain-Specific Entity Addresses . . . . . . . . . . 11
3.4.3. Hierarchy and Inheritance . . . . . . . . . . . . . . 11
3.4.4. Relationship to Cost Map . . . . . . . . . . . . . . 11
4. Property Map Resource . . . . . . . . . . . . . . . . . . . . 11
4.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 11
4.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 12
4.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 12
4.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 12
4.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Filtered Property Map Resource . . . . . . . . . . . . . . . 13
5.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 14
5.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 14
5.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 14
5.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 14
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5.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 15
6. Impact on Legacy ALTO Servers and ALTO Clients . . . . . . . 15
6.1. Impact on Endpoint Property Service . . . . . . . . . . . 15
6.2. Impact on Resource-Specific Properties . . . . . . . . . 15
6.3. Impact on the "pid" Property . . . . . . . . . . . . . . 16
6.4. Impact on Other Properties . . . . . . . . . . . . . . . 16
7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.1. Network Map . . . . . . . . . . . . . . . . . . . . . . . 16
7.2. Property Definitions . . . . . . . . . . . . . . . . . . 17
7.3. Information Resource Directory (IRD) . . . . . . . . . . 17
7.4. Property Map Example . . . . . . . . . . . . . . . . . . 19
7.5. Filtered Property Map Example #1 . . . . . . . . . . . . 19
7.6. Filtered Property Map Example #2 . . . . . . . . . . . . 20
7.7. Filtered Property Map Example #3 . . . . . . . . . . . . 21
7.8. Filtered Property Map Example #4 . . . . . . . . . . . . 22
8. Security Considerations . . . . . . . . . . . . . . . . . . . 23
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
9.1. application/alto-* Media Types . . . . . . . . . . . . . 24
9.2. ALTO Entity Domain Registry . . . . . . . . . . . . . . . 25
9.3. ALTO Endpoint Property Type Registry . . . . . . . . . . 26
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction
The ALTO protocol [RFC7285] introduced the concept of "properties"
attached to "endpoint addresses," and defined the Endpoint Property
Service (EPS) to allow clients to retrieve those properties. While
useful, the EPS, as defined in RFC7285, has at least two limitations.
First, it only allows properties to be associated with 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. Furthermore, recent
proposal ([I-D.ietf-alto-path-vector]) have suggested new classes of
entities (ANE) with properties. The EPS cannot be extended to new
entity domains. Instead, new services, with new request and response
messages, would have to be defined for each new entity domain.
Second, the EPS is only defined as a POST-mode service. Clients must
request the properties for an explicit set of addresses. By
contrast, [RFC7285] defines a GET-mode Cost Map resource which
returns all available costs, so a client can get the full set of
costs once, and then lookup costs without querying the ALTO server.
RFC7285 does not define an equivalent service for endpoint
properties. And it is unlikely a property will be defined for every
possible address. It is very likely that properties will only be
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defined for a subset of addresses, and that subset would be small
enough to enumerate. This is particularly true if blocks of
addresses with a common prefix (e.g., a CIDR) have the same value for
a property. Furthermore, entities in other domains may very well be
enumerable.
This document proposes a new approach to retrieve ALTO properties.
Specifically, it defines two new resource types, namely Property Maps
(see Section 4) and Filtered Property Maps (see Section 5). The
former are GET-mode resources which return the property values for
all entities in a domain, and are analogous to the ALTO's Network
Maps and Cost Maps. The latter are POST-mode resources which return
the values for a set of properties and entities requested by the
client, and are analogous to ALTO's Filtered Network Maps and
Filtered Cost Maps.
Entity domains and property names are extensible, so that new 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 by
the ALTO protocol.
This proposal would subsume the Endpoint Property Service defined in
RFC7285, although that service may be retained for legacy clients
(see Section 6).
2. Definitions and Concepts
2.1. Entity
An entity is an object with a (possibly empty) set of properties.
Every entity is in a domain, such as the IPv4 and IPv6 domains, and
has a unique address.
2.2. Domain
A domain is a family of entities. Two examples are the Internet
address and PID domain (see Section 3.1 and Section 3.2) that this
document will define. An additional example is the proposed domain
of Abstract Network Elements associated with topology and routing, as
suggested by [I-D.ietf-alto-path-vector].
2.3. Entity Address
Each entity has a unique address of the format:
domain-name : domain-specific-entity-address
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Examples from the IP domain include individual 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 type EntityAddr denotes a JSON string with an entity address in
this format.
The format of the second part of an entity address depends on the
domain, and MUST be specified when registering a new domain.
Addresses 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 domain is registered.
Note that entity addresses MAY have different textual
representations, for a given domain. For example, the strings
"ipv6:2001:db8::1" and "ipv6:2001:db8:0:0:0:0:0:1" refer to the same
entity.
2.4. Domain Name
Each domain has a unique name. A domain name MUST be no more than 32
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 names "ipv4" and "ipv6" identify objects in the
Internet address domain (Section 3.1).
The type DomainName denotes a JSON string with a domain name in this
format.
Domain names MUST be registered with the IANA, and the format of the
entity addresses in that domain, as well as any hierarchical or
inheritance rules for those entities, MUST be specified at the same
time.
2.5. Property Name
The space of property names associated with entities defined by this
document is the same as, and is shared with, the endpoint property
names defined by [RFC7285]. Thus entity property names are as
defined in Section 10.8.2 of that document, and MUST be registered
with the "ALTO Endpoint Property Type Registry" defined in
Section 14.3 of that document.
The type PropertyName denotes a JSON string with a property name in
this format.
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A main design decision is that property names are defined in a single
namespace, not specific to a domain, although some properties MAY
only be applicable for particular domains. This design decision is
to enforce a design that similar properties are named similarly.
The interpretation of the value of a property, however, MAY depend on
the domain. For example, suppose the "geo-location" property is
defined as the coordinates of a point, encoded as "latitude longitude
[altitude]." When applied to an entity that represents a specific
host computer, such as an Internet address, the property defines the
host's location. When applied to an entity that represents a set of
computers, such as a CIDR, the property would be the location of the
center of that set. If it is necessary to represent the bounding box
of a set of hosts, another property, such as "geo-region", SHOULD be
defined.
2.6. Property Value
The property value MAY BE defined or undefined. If it is defined, it
SHOULD BE a JSONString or a JSON "null" value. Otherwise, a protocol
implementation SHOULD fail to parse the property value, unless the
implementation is using an extension to this document that indicates
when and how property values of other data types are signaled.
2.7. Hierarchy and Inheritance
Entities in a given domain MAY form hiearchy based on entity address.
Each domain MAY define its own hierarchy and inheritance semantics.
Given a property, the semantics MUST NOT allow an entity with a
defined property value to inherit the property value of another
entity. Given a property, the semantics MAY allow an entity with an
undefined property value to inherit the property value of another
entity. An entity may not be able to inherit a property value if no
other entities satisfy the inheritance conditions defined by the
semantics. The hierarchy and inheritance semantics SHOULD be defined
carefully to avoid multiple inheritance.
2.8. Relationship to Network Maps
[RFC7285] recognizes that some properties MAY be specific to an ALTO
resource, such as a network map. Accordingly [RFC7285] defines the
concept of "resource-specific endpoint properties" (Section 10.8.1),
and indicates that dependency by prefixing the property name with the
ID of the resource on which it depends. That document defines one
resource-specific property, namely the "pid" property, whose value is
the name of the PID containing that endpoint in the associated
network map.
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This document takes a different approach. Instead of defining the
dependency by qualifying the property name, this document attaches
the dependency to the property map as a whole. Thus all properties
in a given property map depend on the same resource. Furthermore,
entity addresses MAY depend on a network map (for example, the
Abstract Network Elements suggested by [I-D.ietf-alto-path-vector]).
Associating the dependency with the property map handles any entity
address dependencies as well.
The "uses" field in an IRD entry defines the dependencies of a
property map resource, and the "dependent-vtags" field in a property
map response defines the dependencies of that map. These fields are
defined in Sections 9.1.5 and 11.1 of [RFC7285], respectively.
This is similar to how RFC7285 handles dependencies between cost maps
and network maps. Recall that cost maps present the costs between
PIDs, and PID names depend on a network map. If an ALTO server
provides the "routingcost" metric for the network maps "net1" and
"net2", then the server defines two separate cost maps, one for
"net1" and the other for "net2".
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 extensions defined in this
document, would, instead, offer two different Property Maps for the
"pid" property, one depending on "net1", the other on "net2".
3. Entity Domains
This document defines the following entity domains. For the
definition of each domain, it includes the following template: domain
name, domain-specific addresses, and hierarchy and inheritance
semantics.
3.1. Internet Address Domains
The document defines two domains (IPv4 and IPv6) for Internet
addresses. Both domains include individual addresses and blocks of
addresses.
3.1.1. IPv4 Domain
3.1.1.1. Domain Name
ipv4
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3.1.1.2. Domain-Specific Entity Addresses
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.
3.1.2. IPv6 Domain
3.1.2.1. Domain Name
ipv6
3.1.2.2. Domain-Specific Entity Addresses
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 ipv4/ipv6 Domains
Both domains allow property values to be inherited. Specifically, if
a property P is not defined for a specific Internet address IP, but P
is defined for some block C which prefix-matches IP, then the address
IP inherits the value of P defined for block C. If more than one
such block defines a value for P, IP 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 property P is not
defined for a block C, but is defined for some block C' prefix-
matches 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.
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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:
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 define a property as not having a value
for a particular entity. That is, a server MAY say that a property
is "defined to have no value", as opposed to the property being
"undefined". If that entity would inherit a value for that property,
then the ALTO server MUST return a "null" value for that property,
and an ALTO client MUST recognize a "null" value means "do not apply
the inheritance rules for this property." If the entity would not
inherit a value, the ALTO server MAY return "null" or MAY just omit
the property. TODO: Discuss more.
If the ALTO Server does not define any properties for an entity, then
the server MAY omit that entity from the response.
3.1.4. Relationship to Network Maps
TODO: Need discussion. An Internet address domain MAY be associated
with an ALTO network map resource. Logically, there is a map of
Internet address entities to property values for each network map
defined by the ALTO server, plus an additional property map for
Internet address entities which are not associated with a network
map. These maps are separate from each other. The prefixes in the
property map do not have to correspond to the prefixes defining the
network map's PIDs. For example, the property map for a network map
MAY assign properties to "ipv4:192.0.2.0/24" even if that prefix is
not associated with any PID in the network map.
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3.2. PID Domain
The PID domain associates property values with the PIDs in a network
map. Accordingly, this domain always depends on a network map.
3.2.1. Domain Name
pid
3.2.2. Domain-Specific Entity Addresses
The entity addresses are the PID names of the associated network map.
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 domain is best for a property. In
general, the Internet address domain is 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
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property that explains why a PID was formed, or how it relates the a
provider's network, would best be associated with the PID domain.
3.4. ANE Domain
3.4.1. Domain Name
ane
3.4.2. Domain-Specific Entity Addresses
The entity address of ane domain is encoded as a JSON string. The
string MUST be no more than 64 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), the at sign ('@', code point
U+0040), the low line ('_', U+005F), or the '.' separator (U+002E).
The '.' separator is reserved for future use and MUST NOT be used
unless specifically indicated in this document, or an extension
document.
3.4.3. Hierarchy and Inheritance
There is no hierarchy or inheritance for properties associated with
ANEs.
3.4.4. Relationship to Cost Map
TBA
4. Property Map Resource
A Property Map returns the properties defined for all entities in one
or more domains. Note that Property Map Resource is not applicable
to ANE domain.
Section 7.4 gives an example of a property map request and its
response.
4.1. Media Type
The media type of an ALTO Property Map resource is "application/alto-
propmap+json".
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4.2. HTTP Method
An ALTO Property Map resource is requested using the HTTP GET method.
4.3. Accept Input Parameters
None.
4.4. Capabilities
The capabilities are defined by an object of type
PropertyMapCapabilities:
object {
DomainName domain-types<1..*>;
PropertyName prop-types<1..*>;
} PropertyMapCapabilities;
where "domain-types" is an array with the domains of the entities in
this property map, and "prop-types" is an array with the names of the
properties returned for entities in those domains. TODO: discuss
semantics and requirements of multiple domains.
4.5. Uses
An array with the resource ID(s) of resource(s) with which the
domains in this map are associated. In most cases, this array will
have at most one ID, for example, for a network map resource. TODO:
discuss semantics and requirements of multiple resources.
4.6. Response
If the 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. 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 {
EntityAddr -> EntityProps;
} PropertyMapData;
object {
PropertyName -> 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.
An ALTO Server MAY explicitly define a property as not having a value
for a particular entity. That is, a server MAY say that a property
is "defined to have no value", as opposed to the property being
"undefined". If that entity would inherit a value for that property,
then the ALTO server MUST return a "null" value for that property,
and an ALTO client MUST recognize a "null" value means "do not apply
the inheritance rules for this property." If the entity would not
inherit a value, the ALTO server MAY return "null" or MAY just omit
the property.
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 domain's
inheritance rules to deduce those values.
5. Filtered Property Map Resource
A Filtered Property Map returns the values of a set of properties for
a set of entities selected by the client.
Section 7.5, Section 7.6 and Section 7.7 give examples of filtered
property map requests and responses.
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5.1. Media Type
The media type of an ALTO Property Map resource is "application/alto-
propmap+json".
5.2. HTTP Method
An ALTO Filtered Property Map resource is requested using the HTTP
POST method.
5.3. 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 {
EntityAddr entities<1..*>;
PropertyName properties<1..*>;
} ReqFilteredPropertyMap;
with fields:
entities: List of entity addresses 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 domains
in this resource's "capabilities" field (Section 5.4).
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 (Section 5.4). 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.
5.4. Capabilities
The capabilities are defined by an object of type
PropertyMapCapabilities, as defined in Section 4.4.
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5.5. Uses
An array with the resource ID(s) of resource(s) with which the
domains in this map are associated. In most cases, this array will
have at most one ID, and it will be for a network map resource.
5.6. Response
The response is the same as for the property map (Section 4.6),
except that it only includes the entities and properties requested by
the client.
Also, the Filtered Property Map response MUST include all inherited
property values for the specified entities (unlike the Full Property
Map, the Filtered Property Map response does not include enough
information for the client to calculate the inherited values).
Discussion Needed: sometimes the client can compute some inherited
property values. In this case, can the Filter Property Map response
only contain the uncomputable inherited property values instead of
all of them?
6. Impact on Legacy ALTO Servers and ALTO Clients
6.1. Impact on Endpoint Property Service
The Property Maps defined in this document provide the same
functionality as the Endpoint Property Service (EPS) defined in
Section 11.4 of [RFC7285]. Accordingly, it is RECOMMENDED that the
EPS be deprecated in favor of Property Maps. However, ALTO servers
MAY provide an EPS for the benefit of legacy clients.
6.2. 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 depended
upon, while global property names have no such prefix. The property
map resources 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.
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6.3. Impact on the "pid" Property
Section 7.1.1 of [RFC7285] defines the resource-specific endpoint
property "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 Endpoint Property Service
MUST use that definition, and that syntax, in the EPS resource.
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 resource 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 resource for
each one.
Second, a client MAY request the "pid" property for a block of
addresses. An ALTO server determines the value of "pid" for an
address block C as follows. Let CS be the set of all address blocks
in the network map. If C is in CS, then the value of "pid" is the
name of the PID associated with C. Otherwise, find the longest block
C' in CS such that C' prefix-matches C, but is shorter than C. If
there is such a block C', the value of "pid" is the name of the PID
associated with C'. If not, then "pid" has no value for block C.
Note that although an ALTO server MAY provide a GET-mode property map
resource 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.
6.4. 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 addresses, rather than just individual
addresses, which might change the semantics of a property.
7. Examples
7.1. Network Map
The examples in this section use a very simple default network map:
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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
Figure 3: Example Network Map
7.2. Property Definitions
The examples in this section use four additional properties, "ISP",
"ASN", "country" and "state", with the following values:
ISP ASN country state
ipv4:192.0.2.0/24: BitsRus - us -
ipv4:192.0.2.0/28: - 12345 - NJ
ipv4:192.0.2.16/28: - 12345 - CT
ipv4:192.0.2.0: - - - PA
Figure 4: Example Property Values
7.3. Information Resource Directory (IRD)
The following IRD defines the relevant resources of the ALTO server.
It provides two Property Map resources, one for the "ISP" and "ASN"
properties, and another for the "country" and "state" properties.
The server could have provided a Property Map resource 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": { ... },
"resources" : {
"default-network-map" : {
"uri" : "http://alto.example.com/networkmap",
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"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" : {
"domain-types": [ "ipv4", "ipv6" ],
"prop-types" : [ "country", "state" ]
}
},
"isp-asn-property-map" : {
"uri" : "http://alto.example.com/propmap/full/inet-ia",
"media-type" : "application/alto-propmap+json",
"capabilities" : {
"domain-types": [ "ipv4", "ipv6" ],
"prop-types" : [ "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" : {
"domain-types": [ "ipv4", "ipv6" ],
"prop-types" : [ "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" : {
"domain-types" : [ "ipv4", "ipv6" ],
"prop-types" : [ "pid" ]
}
},
"availbw-property-map" : {
"uri" : "http://alto.example.com/propmap/lookup/availbw",
"media-type" : "application/alto-propmap+json",
"accepts" : "application/alto-propmapparams+json",
"capabilities" : {
"domain-types" : [ "ane" ],
"prop-types" : [ "availbw", "delay" ]
}
},
"legacy-pid-property-map" : {
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"uri" : "http://alto.example.com/legacy/eps-pid",
"media-type" : "application/alto-endpointprop+json",
"accepts" : "application/alto-endpointpropparams+json",
"capabilities" : {
"prop-types" : [ "default-network-map.pid" ]
}
}
}
Figure 5: Example IRD
7.4. 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 the response does not include the entity
"ipv4:192.0.2.0", because it does not have a value for either of
those properties. Also note that the entities "ipv4:192.0.2.0/28"
and "ipv4:192.0.2.16/28" are refinements of "ipv4:192.0.2.0/24", and
hence inherit its value for "ISP" property. But because that value
is inherited, it is not
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": {
"ipv4:192.0.2.0/24": {"ISP: "BitsRus"},
"ipv4:192.0.2.0/28": {"ASN": "12345"},
"ipv4:192.0.2.16/28": {"ASN": "12345"}
}
}
7.5. 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"}
}
}
7.6. 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 none of the returned property values were
explicitly defined; all values are derived by the inheritance rules
for Internet address entities.
Also note the "ASN" property has the value "12345" for both the
blocks "ipv4:192.0.2.0/28" and "ipv4:192.0.2.16/28", so every address
in the block "ipv4:192.0.2.0/27" has that property value. However
the block "ipv4:192.0.2.0/27" itself does not have a value for "ASN":
address blocks cannot inherit properties from blocks with longer
prefixes, even if every such block has the same value.
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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",
"ipv4:192.0.2.0/27",
"ipv4:192.0.2.0/28" ],
"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"},
"ipv4:192.0.2.0/27": {"country": "us"},
"ipv4:192.0.2.0/28": {"ASN": "12345",
"country": "us",
"state": "NJ"}
}
}
7.7. 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 value of "pid" for the prefix "ipv4:192.0.2.0/26" is
"pid1", even though all addresses in that block are in "pid2",
because "ipv4:192.0.2.0/25" is the longest prefix in the network map
which prefix-matches "ipv4:192.0.2.0/26", and that prefix is in
"pid1".
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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" : [
"ipv4:192.0.2.0",
"ipv4:192.0.2.16",
"ipv4:192.0.2.64",
"ipv4:192.0.2.128",
"ipv4:192.0.2.0/26",
"ipv4:192.0.2.0/30" ],
"properties" : [ "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": {
"ipv4:192.0.2.0": {"pid": "pid2"},
"ipv4:192.0.2.16": {"pid": "pid2"},
"ipv4:192.0.2.64": {"pid": "pid1"},
"ipv4:192.0.2.128": {"pid": "defaultpid"},
"ipv4:192.0.2.0/26": {"pid": "pid1"},
"ipv4:192.0.2.0/30": {"pid": "pid2"}
}
}
7.8. Filtered Property Map Example #4
The following example uses the Filtered Property Map resource to
request the "availbw" property for several abstract network elements.
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POST /propmap/lookup/availbw 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" : [
"ane:L001",
"ane:Lae0",
"ane:L3eb ],
"properties" : [ "availbw" ]
}
HTTP/1.1 200 OK
Content-Length: ###
Content-Type: application/alto-propmap+json
{
"property-map": {
"ane:L001": {"availbw": "55"},
"ane:Lae0": {"availbw": "70"},
"ane:L3eb": {"availbw": "40"}
}
}
8. Security Considerations
As discussed in Section 15 of [RFC7285], properties MAY have
sensitive customer-specific information. If this is the case, an
ALTO Server MAY limit access to those properties by providing several
different Property Maps. For non-sensitive properties, the ALTO
Server would provide a URI which accepts requests from any client.
Sensitive properties, on the other hand, would only be available via
a secure URI which would require client authentication.
Also, while technically this document does not introduce any security
risks not inherent in the Endpoint Property Service defined by
[RFC7285], the GET-mode property map resource defined in this
document does make it easier for a client to download large numbers
of property values. Accordingly, an ALTO Server SHOULD limit GET-
mode Property Maps to properties which do not contain sensitive data.
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9. IANA Considerations
This document defines additional application/alto-* media types, and
extends the ALTO endpoint property registry.
9.1. application/alto-* Media Types
This document registers two additional ALTO media types, listed in
Table 1.
+--------------+--------------------------+-----------------------+
| Type | Subtype | Specification |
+--------------+--------------------------+-----------------------+
| application | alto-propmap+json | Section 4.1 |
| application | alto-propmapparams+json | Section 5.3 |
+--------------+--------------------------+-----------------------+
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].
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
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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:iesg@ietf.org).
9.2. ALTO Entity Domain Registry
This document requests IANA to create and maintain the "ALTO Entity
Domain Registry", listed in Table 2.
+------------+-----------------------------+------------------------+
| Identifier | Entity Address Encoding | Hierarchy & |
| | | Inheritance |
+------------+-----------------------------+------------------------+
| ipv4 ipv6 | See Section 3.1.1 See | See Section 3.1.3 See |
| pid ane | Section 3.1.2 See Section | Section 3.1.3 None |
| | 3.2 See Section 3.4 | None |
+------------+-----------------------------+------------------------+
Table 2: ALTO Entity Domain Names.
This registry serves two purposes. First, it ensures uniqueness of
identifiers referring to ALTO entity domains. Second, it states the
requirements for allocated domain names.
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 EntityName, 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 2.4. Identifiers are
to be recorded and displayed as strings.
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Requests 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 Address Encoding: The procedure for encoding the address of
an entity of the registered type as an EntityAddr (see
Section 2.3).
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 Security Considerations: In some usage scenarios, entity addresses
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.
9.3. ALTO Endpoint Property Type Registry
The ALTO Endpoint Property Type Registry was created by [RFC7285].
If possible, the name of that registry SHOULD be changed to "ALTO
Entity Property Type Registry", to indicate that it is not restricted
to Endpoint Properties. If it is not feasible to change the name,
the description MUST be amended to indicate that it registers
properties in all domains, rather than just the Internet address
domain.
10. References
[I-D.ietf-alto-path-vector]
Bernstein, G., Chen, S., Gao, K., Lee, Y., Roome, W.,
Scharf, M., Yang, Y., and J. Zhang, "ALTO Extension: Path
Vector Cost Mode", draft-ietf-alto-path-vector-00 (work in
progress), May 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
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[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,
<http://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, <http://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,
<http://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,
<http://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, <http://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,
<http://www.rfc-editor.org/info/rfc7285>.
Authors' Addresses
Wendy Roome
Nokia Bell Labs
600 Mountain Ave, Rm 3B-324
Murray Hill, NJ 07974
USA
Phone: +1-908-582-7974
Email: wendy@roome.com
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Y. Yang
Yale University
51 Prospect Street
New Haven, CT 06511
USA
Phone: +1-203-432-6400
Email: yry@cs.yale.edu
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