ALTO WG W. Roome
Internet-Draft Nokia Bell Labs
Intended status: Standards Track S. Chen
Expires: December 31, 2018 Tongji University
S. Randriamasy
Nokia Bell Labs
Y. Yang
Yale University
J. Zhang
Tongji University
June 29, 2018
Unified Properties for the ALTO Protocol
draft-ietf-alto-unified-props-new-04
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 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 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 December 31, 2018.
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Copyright Notice
Copyright (c) 2018 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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions and Concepts . . . . . . . . . . . . . . . . . . 4
2.1. Entity . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Entity Domain . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Domain Name . . . . . . . . . . . . . . . . . . . . . . . 5
2.4. Entity Address . . . . . . . . . . . . . . . . . . . . . 5
2.5. Property Name . . . . . . . . . . . . . . . . . . . . . . 6
2.6. Hierarchy and Inheritance . . . . . . . . . . . . . . . . 6
2.7. Relationship with Other ALTO Resources . . . . . . . . . 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
4. Property Map Resource . . . . . . . . . . . . . . . . . . . . 11
4.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 11
4.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 11
4.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 11
4.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Filtered Property Map Resource . . . . . . . . . . . . . . . 13
5.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 13
5.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 13
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5.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 13
5.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 14
5.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 14
6. Impact on Legacy ALTO Servers and ALTO Clients . . . . . . . 14
6.1. Impact on Endpoint Property Service . . . . . . . . . . . 15
6.2. Impact on Resource-Specific Properties . . . . . . . . . 15
6.3. Impact on the pid Property . . . . . . . . . . . . . . . 15
6.4. Impact on Other Properties . . . . . . . . . . . . . . . 16
7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.1. Network Map . . . . . . . . . . . . . . . . . . . . . . . 16
7.2. Property Definitions . . . . . . . . . . . . . . . . . . 16
7.3. Information Resource Directory (IRD) . . . . . . . . . . 16
7.4. Property Map Example . . . . . . . . . . . . . . . . . . 18
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 . . . . . . . . . . . . . . . . . . . 24
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
9.1. application/alto-* Media Types . . . . . . . . . . . . . 24
9.2. ALTO Entity Domain Registry . . . . . . . . . . . . . . . 25
9.2.1. Consistency Procedure between ALTO Address Type
Registry and ALTO Entity Domain Registry . . . . . . 26
9.2.2. ALTO Entity Domain Registration Process . . . . . . . 27
9.3. ALTO Endpoint Property Type Registry . . . . . . . . . . 28
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 28
10.1. Normative References . . . . . . . . . . . . . . . . . . 28
10.2. Informative References . . . . . . . . . . . . . . . . . 29
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
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. 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
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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 lookup without querying the ALTO
server. [RFC7285] does not define an equivalent service for endpoint
properties. At first a map 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 address. It is much more likely that properties
will only be 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 the ALTO's Filtered Network Maps and
Filtered Cost Maps.
Additionally, this document introduces ALTO Entity Domains, where
entities extend the concept of endpoints to objects that may be
endpoints as defined in [RFC7285] but also, for example, PIDs,
Abstract Network Elements as defined in [I-D.ietf-alto-path-vector]
or cells. As a consequence, ALTO Entity Domains are a super-set of
ALTO Address Types and their relation is specified in Section 9.2.1.
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 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
The entity is an extended concept of the endpoint defined in
Section 2.1 of [RFC7285]. An entity is an object with a (possibly
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empty) set of properties. Every entity is in a domain, such as the
IPv4 and IPv6 domains, and has a unique address.
2.2. Entity Domain
An entity 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.
2.3. Domain Name
Each entity 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 (see Section 3.1).
The type DomainName is used in this document to denote 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 entity domain, as well as any hierarchical
or inheritance rules for those entities, MUST be specified at the
same time.
2.4. Entity Address
Each entity has a unique address of the format:
domain-name : domain-specific-entity-address
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 is used in this document to denote a JSON string
with an entity address in this format.
The format of the second part of an entity address depends on the
entity domain, and MUST be specified when registering a new entity
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 entity domain is
registered.
Note that an entity address MAY have different textual
representations, for a given entity domain. For example, the strings
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"ipv6:2001:db8::1" and "ipv6:2001:db8:0:0:0:0:0:1" refer to the same
entity.
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 9.3 of that document. The type PropertyName denotes a JSON
string with a property name in this format.
This document defines uniform property names specified in a single
property name space rather than being scoped by a specific entity
domain, although some properties may only be applicable for
particular entity domains. This design decision is to enforce a
design so that similar properties are named similarly. The
interpretation of the value of a property, however, may depend on the
entity domain. For example, suppose 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, 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. Hierarchy and Inheritance
Entities in a given domain MAY form hierarchy based on entity
address. Each entity domain 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. If and only if the property of an
entity is undefined, the hierarchy and inheritance rules are applied.
2.7. Relationship with Other ALTO Resources
[RFC7285] recognizes that some properties MAY be specific to another
ALTO resource, such as a network map. Accordingly [RFC7285] defines
the concept of "resource-specific endpoint properties" (see
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 entity domains. Thus all properties of a
specific entity domain depend on the same resource, the properties of
another entity domain may depend on another resource. For example,
entities in the PID domain depend on a network map.
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.
The "uses" field in an IRD entry MUST NOT include two dependent
resources with the same media type. 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 entity 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 entity domains (IPv4 and IPv6) for Internet
addresses. Both entity 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 entity 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 property P is not
defined for a block C, but is defined for some block C' which 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.
As an example, suppose that a server defines the property P for the
following entities:
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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 indicate a property as not having a
value for a particular entity. That is, a server MAY say that
property A 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 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.
3.1.4. Relationship to Network Maps
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
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not associated with a network map. So, if there are n network maps,
the server can provide n+1 maps of Internet address entities to
property values. 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.
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. 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 entity domain is the best for a
property. In general, the Internet address domain is RECOMMENDED for
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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. Property Map Resource
A Property Map returns the properties defined for all entities in one
or more domains.
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".
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 entity-domain-types<1..*>;
PropertyName prop-types<1..*>;
} PropertyMapCapabilities;
where "entity-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.
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4.5. Uses
An array with the resource ID(s) of resource(s) with which the entity
domains in this map are associated. In most cases, this array will
have at most one ID, for example, for a network map resource.
However, the "uses" field MUST NOT contain two resources of the same
resource type. For example, if a property map depends on network map
resource, the "uses" field MUST include exactly one network map
resource.
4.6. 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. The
data component of a Property Map response is named "property-map",
which is a JSON object of type PropertyMapData, where:
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.
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.
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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.
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 entity
domains in this resource's "capabilities" field (see 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 (see 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.
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5.4. Capabilities
The capabilities are defined by an object of type
PropertyMapCapabilities, as defined in Section 4.4.
5.5. Uses
An array with the resource ID(s) of resource(s) with which the entity
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 (see 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).
If an entity 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]. An entity can be invalid if the domain of the entity
is not defined in the IRD for this service or the entity address is
an invalid address of the entity domain. On the other hand, a valid
entity address is not an error, even if the server does not define a
value for a requested property. In this case, the server MUST omit
that property from the response for only that entity. If a request
contains a property in "properties" and the property is not specified
in the IRD for the service, the ALTO server MUST return an
"E_INVALID_FIELD_VALUE" error defined in Section 8.5.2 of [RFC7285].
The "value" of the error message SHOULD indicate the wrong property.
If the ALTO server does not define a requested property's value for a
particular entity, then it MUST omit that property from the response
for only that endpoint.
If the ALTO server does not support a requested entity's domain, then
it MUST return an E_INVALID_FIELD_VALUE error defined in
Section 8.5.2 of [RFC7285].
6. Impact on Legacy ALTO Servers and ALTO Clients
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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 depend
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.
6.3. 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 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
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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:
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
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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",
"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-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" : {
"entity-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" : {
"entity-domain-types": [ "ipv4", "ipv6" ],
"prop-types" : [ "ISP", "ASN", "country", "state" ]
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}
},
"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-domain-types" : [ "ipv4", "ipv6" ],
"prop-types" : [ "pid" ]
}
},
"location-property-map": {
"uri": "http://alto.exmaple.com/propmap/location",
"media-type": "application/alto-propmap+json",
"accepts": "application/alto-propmapparams+json",
"uses" : [ "default-network-map" ],
"capabilities": {
"domain-types": [ "pid" ],
"prop-types": [ "country", "state" ]
}
},
"legacy-pid-property" : {
"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 explicitly listed in the property map.
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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 is
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 "country" and "state" property for several PIDs defined
in "default-network-map".
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POST /propmap/lookup/location 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" : ["pid:pid3",
"pid:pid4",
"pid:pid5",
"pid:pid6",
"pid:pid7"],
"properties" : [ "country", "state" ]
}
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": {
"pid:pid3": {
"country": "us",
"state": "CA"
},
"pid:pid4": {
"country": "us",
"state": "CT"
},
"pid:pid5": {
"country": "ca",
"state": "QC"
},
"pid:pid6": {
"country": "ca",
"state": "NT"
},
"pid:pid7": {
"country": "fr"
}
}
}
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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.
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].
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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 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.
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+-------------+--------------------------+--------------------------+
| Identifier | Entity Address Encoding | Hierarchy & Inheritance |
+-------------+--------------------------+--------------------------+
| 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.
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.
9.2.1. 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
address 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 address for the candidate domain
identifier. This has been done for the identifiers "ipv4" and
"ipv6" in Table 2.
o Whether the candidate entity address of the entity domain is able
to be an endpoint address, as defined in Sections 2.1 and 2.2 of
[RFC7285].
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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 addresses match a known "network"
address type?
* if yes: (e.g., cell, MAC or socket addresses)
+ 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 9.2.2 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 9.2.2.
9.2.2. 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 EntityAddr, 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 2.3. 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.
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o Entity Address Encoding: The procedure for encoding the address of
an entity of the registered type as an EntityAddr (see
Section 2.4). If corresponding entity addresses of an entity
domain match a known "network" address type, the Entity Address
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 address and the
corresponding full-length prefix MUST be considered aliases for
the same entity.
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 entity domains, rather than just the Internet
address domain.
10. References
10.1. 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>.
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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,
<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>.
10.2. Informative 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 Type", draft-ietf-alto-path-vector-03 (work in
progress), March 2018.
Authors' Addresses
Wendy Roome
Nokia Bell Labs (Retired)
124 Burlington Rd
Murray Hill, NJ 07974
USA
Phone: +1-908-464-6975
Email: wendy@wdroome.com
Roome, et al. Expires December 31, 2018 [Page 29]
Internet-Draft Unified Properties June 2018
Shiwei Dawn Chen
Tongji University
4800 Caoan Road
Shanghai 201804
China
Email: dawn_chen_f@hotmail.com
Sabine Randriamasy
Nokia Bell Labs
Route de Villejust
NOZAY 91460
FRANCE
Email: Sabine.Randriamasy@nokia-bell-labs.com
Y. Richard Yang
Yale University
51 Prospect Street
New Haven, CT 06511
USA
Phone: +1-203-432-6400
Email: yry@cs.yale.edu
Jingxuan Jensen Zhang
Tongji University
4800 Caoan Road
Shanghai 201804
China
Email: jingxuan.n.zhang@gmail.com
Roome, et al. Expires December 31, 2018 [Page 30]
