ALTO & CDNI WGs J. Seedorf
Internet-Draft HFT Stuttgart - Univ. of Applied Sciences
Intended status: Standards Track Y. Yang
Expires: August 27, 2020 Tongji/Yale
K. Ma
Ericsson
J. Peterson
Neustar
J. Zhang
Tongji
February 24, 2020
Content Delivery Network Interconnection (CDNI) Request Routing: CDNI
Footprint and Capabilities Advertisement using ALTO
draft-ietf-alto-cdni-request-routing-alto-10
Abstract
The Content Delivery Networks Interconnection (CDNI) framework
[RFC6707] defines a set of protocols to interconnect CDNs, to achieve
multiple goals such as extending the reach of a given CDN to areas
that are not covered by that particular CDN. One component that is
needed to achieve the goal of CDNI described in [RFC7336] is the CDNI
Request Routing Footprint & Capabilities Advertisement interface
(FCI). [RFC8008] defines precisely the semantics of FCI and provides
guidelines on the FCI protocol, but the exact protocol is explicitly
outside the scope of that document. This document defines an FCI
protocol using the Application-Layer Traffic Optimization (ALTO)
protocol, following the guidelines defined in [RFC8008].
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 August 27, 2020.
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Copyright Notice
Copyright (c) 2020 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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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. Background . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Semantics of FCI Advertisement . . . . . . . . . . . . . 5
2.2. ALTO Background and Benefits . . . . . . . . . . . . . . 6
3. CDNI FCI Service . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 8
3.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 8
3.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 8
3.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 9
3.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 9
3.7. Examples . . . . . . . . . . . . . . . . . . . . . . . . 11
3.7.1. IRD Example . . . . . . . . . . . . . . . . . . . . . 11
3.7.2. Basic Example . . . . . . . . . . . . . . . . . . . . 14
3.7.3. Incremental Updates Example . . . . . . . . . . . . . 15
4. CDNI FCI Service using ALTO Network Map . . . . . . . . . . . 17
4.1. Network Map Footprint Type: altopid . . . . . . . . . . . 17
4.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2.1. IRD Example . . . . . . . . . . . . . . . . . . . . . 17
4.2.2. ALTO Network Map for CDNI FCI Footprints Example . . 18
4.2.3. ALTO PID Footprints in CDNI FCI . . . . . . . . . . . 18
4.2.4. Incremental Updates Example . . . . . . . . . . . . . 19
5. Filtered CDNI FCI using Capabilities . . . . . . . . . . . . 21
5.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 21
5.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 21
5.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 21
5.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 22
5.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 22
5.7. Examples . . . . . . . . . . . . . . . . . . . . . . . . 23
5.7.1. IRD Example . . . . . . . . . . . . . . . . . . . . . 23
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5.7.2. Basic Example . . . . . . . . . . . . . . . . . . . . 23
5.7.3. Incremental Updates Example . . . . . . . . . . . . . 25
6. Query Footprint Properties using ALTO Property Map Service . 26
6.1. Representing Footprint Objects as Property Map Entities . 27
6.1.1. ASN Domain . . . . . . . . . . . . . . . . . . . . . 27
6.1.2. COUNTRYCODE Domain . . . . . . . . . . . . . . . . . 28
6.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . 28
6.2.1. IRD Example . . . . . . . . . . . . . . . . . . . . . 28
6.2.2. Property Map Example . . . . . . . . . . . . . . . . 28
6.2.3. Filtered Property Map Example . . . . . . . . . . . . 30
6.2.4. Incremental Updates Example . . . . . . . . . . . . . 32
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33
7.1. CDNI Metadata Footprint Type Registry . . . . . . . . . . 33
7.2. ALTO Entity Domain Type Registry . . . . . . . . . . . . 34
7.3. ALTO Entity Property Type Registry . . . . . . . . . . . 34
8. Security Considerations . . . . . . . . . . . . . . . . . . . 34
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 35
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.1. Normative References . . . . . . . . . . . . . . . . . . 36
10.2. Informative References . . . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37
1. Introduction
The ability to interconnect multiple content delivery networks (CDNs)
has many benefits, including increased coverage, capability, and
reliability. The Content Delivery Networks Interconnection (CDNI)
framework [RFC6707] defines four interfaces to achieve the
interconnection of CDNs: (1) the CDNI Request Routing Interface; (2)
the CDNI Metadata Interface; (3) the CDNI Logging Interface; and (4)
the CDNI Control Interface.
Among the four interfaces, the CDNI Request Routing Interface
provides key functions, as specified in [RFC6707]: "The CDNI Request
Routing interface enables a Request Routing function in an Upstream
CDN to query a Request Routing function in a Downstream CDN to
determine if the Downstream CDN is able (and willing) to accept the
delegated Content Request. It also allows the Downstream CDN to
control what should be returned to the User Agent in the redirection
message by the upstream Request Routing function." At a high level,
the scope of the CDNI Request Routing Interface, therefore, contains
two main tasks: (1) determining if the dCDN (downstream CDN) is
willing to accept a delegated content request, and (2) redirecting
the content request coming from a uCDN (upstream CDN) to the proper
entry point or entity in the dCDN.
Correspondingly, the request routing interface is broadly divided
into two functionalities: (1) the CDNI Footprint & Capabilities
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Advertisement interface (FCI) defined in [RFC8008], and (2) the CDNI
Request Routing Redirection interface (RI) defined in [RFC7975].
Since this document focuses on the first functionality (CDNI FCI),
below is more details about it.
Specifically, CDNI FCI allows both an advertisement from a dCDN to a
uCDN (push) and a query from a uCDN to a dCDN (pull) so that the uCDN
knows whether it can redirect a particular user request to that dCDN.
A key component in defining CDNI FCI is defining objects describing
the footprints and capabilities of a dCDN. Such objects are already
defined in [RFC8008]. A protocol to transport and update such
objects between a uCDN and a dCDN, however, is not defined. Hence,
the scope of this document is to define such a protocol by
introducing a new Application-Layer Traffic Optimization (ALTO)
[RFC7285] service called "CDNI FCI Service".
There are multiple benefits in using ALTO as a transport protocol, as
discussed in Section 2.2.
The rest of this document is organized as follows. Section 2
provides non-normative background on both CDNI FCI and ALTO.
Section 3 introduces the most basic service, called "CDNI FCI
Service", to realize CDNI FCI using ALTO. Section 4 demonstrates a
key benefit of using ALTO: the ability to integrate CDNI FCI with
ALTO network maps. Such integration provides new granularity to
describe footprints. Section 5 introduces "Filtered CDNI FCI
Service" to allow a uCDN to get footprints with given capabilities
instead of getting the full resource, which can be large. Section 6
further shows another benefit of using ALTO: the ability to query
footprint properties using ALTO unified properties. In this way, a
uCDN can effectively fetch capabilities of footprints in which it is
interested. IANA and security considerations are discussed in
Section 7 and Section 8 respectively.
2. Background
The design of CDNI FCI transport using ALTO depends on the
understanding of both FCI semantics and ALTO. Hence, this document
starts with a non-normative review for both. The review uses the
terminologies for CDNI as defined in [RFC6707], [RFC8006] and
[RFC8008]; those for ALTO as defined in [RFC7285] and [I-D.ietf-alto-
unified-props-new].
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2.1. Semantics of FCI Advertisement
[RFC8008] (CDNI "Footprint and Capabilities Semantics") defines the
semantics of CDNI FCI, provides guidance on what Footprint and
Capabilities mean in a CDNI context, and specifies the requirements
on the CDNI FCI transport protocol. The definitions in [RFC8008]
depend on [RFC8006]. Below is a non-normative review of key related
points of [RFC8008] and [RFC8006]. For detailed information and
normative specification, the reader is referred to these two RFCs.
o Multiple types of mandatory-to-implement footprints (ipv4cidr,
ipv6cidr, asn, and countrycode) are defined in [RFC8006]. A "Set
of IP-prefixes" can contain both full IP addresses (i.e., a /32
for IPv4 or a /128 for IPv6) and IP prefixes with an arbitrary
prefix length. There must also be support for multiple IP address
versions, i.e., IPv4 and IPv6, in such a footprint.
o Multiple "base" capabilities are defined [TODO: which RFC]. By
"base" capabilities, they are required in all cases and therefore
constitute mandatory capabilities to be supported by the CDNI FCI:
(1) Delivery Protocol, (2) Acquisition Protocol, (3) Redirection
Mode, (4) Capabilities related to CDNI Logging, and (5)
Capabilities related to CDNI Metadata.
o Footprint and capabilities are defined together and cannot be
interpreted independently from each other. Specifically,
[RFC8008] integrates footprint and capabilities with an approach
of "capabilities with footprint restrictions", by expressing
capabilities on a per footprint basis.
o Specifically, for all mandatory-to-implement footprint types,
footprints can be viewed as constraints for delegating requests to
a dCDN: A dCDN footprint advertisement tells the uCDN the
limitations for delegating a request to the dCDN. For IP prefixes
or ASN(s), the footprint signals to the uCDN that it should
consider the dCDN a candidate only if the IP address of the
request routing source falls within the prefix set (or ASN,
respectively). The CDNI specifications do not define how a given
uCDN determines what address ranges are in a particular ASN.
Similarly, for country codes, a uCDN should only consider the dCDN
a candidate if it covers the country of the request routing
source. The CDNI specifications do not define how a given uCDN
determines the country of the request routing source. Multiple
footprint constraints are additive, i.e., the advertisement of
different types of footprint narrows the dCDN candidacy
cumulatively.
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o Given that a large part of Footprint and Capabilities
Advertisement may actually happen in contractual agreements, the
semantics of CDNI Footprint and Capabilities advertisement refers
to answering the following question: what exactly still needs to
be advertised by the CDNI FCI? For instance, updates about
temporal failures of part of a footprint can be useful information
to convey via the CDNI FCI. Such information would provide
updates on information previously agreed in contracts between the
participating CDNs. In other words, the CDNI FCI is a means for a
dCDN (downstream CDN) to provide changes/updates regarding a
footprint and/or capabilities that it has prior agreed to serve in
a contract with a uCDN (upstream CDN). Hence, server push and
incremental encoding will be necessary techniques.
2.2. ALTO Background and Benefits
Application-Layer Traffic Optimization (ALTO) [RFC7285] defines an
approach for conveying network layer (topology) information to
"guide" the resource provider selection process in distributed
applications that can choose among several candidate resources
providers to retrieve a given resource. Usually, it is assumed that
an ALTO server conveys information that these applications cannot
measure or have difficulty measuring themselves [RFC5693].
Originally, ALTO was motivated by optimizing cross-ISP traffic
generated by P2P applications [RFC5693]. However, ALTO can also be
used for improving the request routing in CDNs. In particular, the
CDNI problem statement [RFC6707] explicitly mentions ALTO as a
candidate protocol for "actual algorithms for selection of CDN or
Surrogate by Request-Routing systems".
The following reasons make ALTO a suitable candidate protocol for
dCDN (downstream CDN) selection as part of CDNI request routing and,
in particular, for an FCI protocol:
o ALTO is a protocol specifically designed to improve application
layer traffic (and application layer connections among hosts on
the Internet) by providing additional information to applications
that these applications could not easily retrieve themselves.
This matches the need of CDNI: a uCDN wants to improve application
layer CDN request routing by using information (provided by a
dCDN) that the uCDN could not easily obtain otherwise. Hence,
ALTO can help a uCDN to select a proper dCDN by first providing
dCDNs' capabilities as well as footprints (see Section 3) and then
providing costs of surrogates in a dCDN by ALTO cost maps.
o The semantics of an ALTO network map is an exact match for the
needed information to convey a footprint by a dCDN, in particular,
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if such a footprint is being expressed by IP-prefix ranges.
Please see Section 4.
o Security: The identification between uCDNs and dCDNs is an
important requirement. ALTO maps can be signed and hence provide
inherent integrity protection. Please see Section 8.
o RESTful-Design: The ALTO protocol has undergone extensive
revisions in order to provide a RESTful design regarding the
client-server interaction specified by the protocol. A CDNI FCI
interface based on ALTO would inherit this RESTful design. Please
see Section 3.
o Error-handling: The ALTO protocol provides extensive error-
handling in the whole request and response process (see
Section 8.5 of [RFC7285]). A CDNI FCI interface based on ALTO
would inherit this this extensive error-handling framework.
Please see Section 5.
o Filtered map service: The ALTO map filtering service would allow a
uCDN to query only for parts of an ALTO map. For example, the
ALTO filtered property map service can enable a uCDN to query
properties of a part of footprints efficiently (see Section 6).
o Server-initiated Notifications and Incremental Updates: When the
footprint or the capabilities of a dCDN change (i.e., unexpectedly
from the perspective of a uCDN), server-initiated notifications
would enable a dCDN to inform a uCDN about such changes directly.
Consider the case where - due to failure - part of the footprint
of the dCDN is not functioning, i.e., the CDN cannot serve content
to such clients with reasonable QoS. Without server-initiated
notifications, the uCDN might still use a recent network and cost
map from the dCDN, and therefore redirect requests to the dCDN
which it cannot serve. Similarly, the possibility for incremental
updates would enable efficient conveyance of the aforementioned
(or similar) status changes by the dCDN to the uCDN. The newest
design of ALTO supports server pushed incremental updates
[I-D.ietf-alto-incr-update-sse].
o Content Availability on Hosts: A dCDN might want to express CDN
capabilities in terms of certain content types (e.g., codecs/
formats, or content from certain content providers). The new
endpoint property for ALTO would enable a dCDN to make such
information available to a uCDN. This would enable a uCDN to
determine whether a dCDN actually has the capabilities for a given
type of content requested.
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o Resource Availability on Hosts or Links: The capabilities on links
(e.g., maximum bandwidth) or caches (e.g., average load) might be
useful information for a uCDN for optimized dCDN selection. For
instance, if a uCDN receives a streaming request for content with
a certain bitrate, it needs to know if it is likely that a dCDN
can fulfill such stringent application-level requirements (i.e.,
can be expected to have enough consistent bandwidth) before it
redirects the request. In general, if ALTO could convey such
information via new endpoint properties, it would enable more
sophisticated means for dCDN selection with ALTO. ALTO Path
Vector Extension [I-D.ietf-alto-path-vector] is designed to allow
ALTO clients to query information such as capacity regions for a
given set of flows.
3. CDNI FCI Service
The ALTO protocol is based on an ALTO Information Service Framework
which consists of several services, where all ALTO services are
"provided through a common transport protocol, messaging structure
and encoding, and transaction model" [RFC7285]. The ALTO protocol
specification [RFC7285] defines several such services, e.g., the ALTO
map service.
This document defines a new ALTO Service called "CDNI FCI Service"
which conveys JSON objects of media type "application/alto-
cdnifci+json". These JSON objects are used to transport
BaseAdvertisementObject objects defined in [RFC8008]; this document
specifies how to transport such BaseAdvertisementObject objects via
the ALTO protocol with the ALTO "CDNI FCI Service". Similar to other
ALTO services, this document defines the ALTO information resource
for the "CDNI FCI Service" as follows.
3.1. Media Type
The media type of the CDNI FCI resource is "application/alto-
cdnifci+json".
3.2. HTTP Method
A CDNI FCI resource is requested using the HTTP GET method.
3.3. Accept Input Parameters
None.
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3.4. Capabilities
None.
3.5. Uses
The "uses" field SHOULD NOT appear unless the CDNI FCI resource
depends on some ALTO information resources. If the CDNI FCI resource
has some dependent resources, the resource IDs of its dependent
resources MUST be included into the "uses" field. This document only
defines one potential dependent resource for the CDNI FCI resource.
See Section 4 for details of when and how to use it. Future
documents may extend the CDNI FCI resource and allow other dependent
resources.
3.6. Response
The "meta" field of a CDNI FCI response MUST include the "vtag" field
defined in Section 10.3 of [RFC7285]. This field provides the
version of the retrieved CDNI FCI resource.
If a CDNI FCI response depends on an ALTO information resource, it
MUST include the "dependent-vtags" field, whose value is an array to
indicate the version tags of the resources used, where each resource
is specified in "uses" of its IRD entry.
The data component of an ALTO CDNI FCI response is named "cdni-fci",
which is a JSON object of type CDNIFCIData:
object {
CDNIFCIData cdni-fci;
} InfoResourceCDNIFCI : ResponseEntityBase;
object {
BaseAdvertisementObject capabilities<1..*>;
} CDNIFCIData;
Specifically, a CDNIFCIData object is a JSON object that includes
only one property named "capabilities", whose value is an array of
BaseAdvertisementObject objects.
The syntax and semantics of BaseAdvertisementObject are well defined
in Section 5.1 of [RFC8008]. A BaseAdvertisementObject object
includes multiple properties, including capability-type, capability-
value, and footprints, where footprints are defined in
Section 4.2.2.2 of [RFC8006].
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To be self-contained, below is a non-normative specification of
BaseAdvertisementObject. As mentioned above, the normative
specification of BaseAdvertisementObject is in [RFC8008]
object {
JSONString capability-type;
JSONValue capability-value;
Footprint footprints<0..*>;
} BaseAdvertisementObject;
object {
JSONString footprint-type;
JSONString footprint-value<1..*>;
} Footprint;
For each BaseAdvertisementObject, the ALTO client MUST interpret
footprints appearing multiple times as if they appeared only once.
If footprints in a BaseAdvertisementObject is null or empty or not
appearing, the ALTO client MUST understand that the capabilities in
this BaseAdvertisementObject have the "global" coverage.
Note: Further optimization of BaseAdvertisement objects to
effectively provide the advertisement of capabilities with footprint
restrictions is certainly possible. For example, these two examples
below both describe that the dCDN can provide capabilities
["http/1.1", "https/1.1"] for the same footprints. However, the
latter one is smaller in its size.
EXAMPLE 1
{
"meta" : {...},
"cdni-fci": {
"capabilities": [
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"http/1.1"
]
},
"footprints": [
<Footprint objects>
]
},
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
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"delivery-protocols": [
"https/1.1"
]
},
"footprints": [
<Footprint objects>
]
}
]
}
}
EXAMPLE 2
{
"meta" : {...},
"cdni-fci": {
"capabilities": [
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"https/1.1",
"http/1.1"
]
},
"footprints": [
<Footprint objects>
]
}
]
}
}
Since such optimizations are not required for the basic
interconnection of CDNs, the specifics of such mechanisms are outside
the scope of this document.
3.7. Examples
3.7.1. IRD Example
Below is the information resource directory (IRD) of a simple,
example ALTO server. The server provides both base ALTO information
resources (e.g., network maps) and CDNI FCI related information
resources (e.g., CDNI FCI resource), demonstrating a single,
integrated environment.
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Specifically, the IRD announces two network maps, one CDNI FCI
resource without dependency, one CDNI FCI resource depending on a
network map, one filtered CDNI FCI resource to be defined in
Section 5, one property map including "cdni-fci-capabilities" as its
entity property, one filtered property map including "cdni-fci-
capabilities" and "pid" as its entity properties, and two update
stream services (one for updating CDNI FCI resources, and the other
for updating property maps).
GET /directory HTTP/1.1
Host: alto.example.com
Accept: application/alto-directory+json,application/alto-error+json
{
"meta" : { ... },
"resources": {
"my-default-network-map": {
"uri" : "http://alto.example.com/networkmap",
"media-type" : "application/alto-networkmap+json"
},
"my-eu-netmap" : {
"uri" : "http://alto.example.com/myeunetmap",
"media-type" : "application/alto-networkmap+json"
},
"my-default-cdnifci": {
"uri" : "http://alto.example.com/cdnifci",
"media-type": "application/alto-cdnifci+json"
},
"my-cdnifci-with-pid-footprints": {
"uri" : "http://alto.example.com/networkcdnifci",
"media-type" : "application/alto-cdnifci+json",
"uses" : [ "my-eu-netmap" ]
},
"my-filtered-cdnifci" : {
"uri" : "http://alto.example.com/cdnifci/filtered",
"media-type" : "application/alto-cdnifci+json",
"accepts" : "application/alto-cdnifcifilter+json",
"uses" : [ "my-default-cdnifci" ]
},
"cdnifci-property-map" : {
"uri" : "http://alto.example.com/propmap/full/cdnifci",
"media-type" : "application/alto-propmap+json",
"uses": [ "my-default-cdni" ],
"capabilities" : {
"mappings": {
"ipv4": [ "my-default-cdni.cdni-fci-capabilities" ],
"ipv6": [ "my-default-cdni.cdni-fci-capabilities" ],
"countrycode": [
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"my-default-cdni.cdni-fci-capabilities" ],
"asn": [ "my-default-cdni.cdni-fci-capabilities" ],
}
}
},
"filtered-cdnifci-property-map" : {
"uri" : "http://alto.example.com/propmap/lookup/cdnifci-pid",
"media-type" : "application/alto-propmap+json",
"accepts" : "application/alto-propmapparams+json",
"uses": [ "my-default-cdni", "my-default-network-map" ],
"capabilities" : {
"mappings": {
"ipv4": [ "my-default-cdni.cdni-fci-capabilities",
"my-default-network-map.pid" ],
"ipv6": [ "my-default-cdni.cdni-fci-capabilities",
"my-default-network-map.pid" ],
"countrycode": [
"my-default-cdni.cdni-fci-capabilities" ],
"asn": [ "my-default-cdni.cdni-fci-capabilities" ],
}
}
},
"update-my-cdni-fci" : {
"uri": "http:///alto.example.com/updates/cdnifci",
"media-type" : "text/event-stream",
"accepts" : "application/alto-updatestreamparams+json",
"uses" : [
"my-default-network-map",
"my-eu-netmap",
"my-default-cdnifci",
"my-filtered-cdnifci"
"my-cdnifci-with-pid-footprints"
],
"capabilities" : {
"incremental-change-media-types" : {
"my-default-network-map" : "application/json-patch+json",
"my-eu-netmap" : "application/json-patch+json",
"my-default-cdnifci" :
"application/merge-patch+json,application/json-patch+json",
"my-filtered-cdnifci" :
"application/merge-patch+json,application/json-patch+json",
"my-cdnifci-with-pid-footprints" :
"application/merge-patch+json,application/json-patch+json"
}
}
},
"update-my-props": {
"uri" : "http://alto.example.com/updates/properties",
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"media-type" : "text/event-stream",
"uses" : [
"cdnifci-property-map",
"filtered-cdnifci-property-map"
],
"capabilities" : {
"incremental-change-media-types": {
"cdnifci-property-map" :
"application/merge-patch+json,application/json-patch+json",
"filtered-cdnifci-property-map":
"application/merge-patch+json,application/json-patch+json"
}
}
}
}
}
3.7.2. Basic Example
This basic example demonstrates a simple CDNI FCI resource, which
does not depend on other resources. There are three
BaseAdvertisementObjects in this resource and these objects'
capabilities are http/1.1 delivery protocol, [http/1.1, https/1.1]
delivery protocol, and https/1.1 acquisition protocol, respectively.
GET /cdnifci HTTP/1.1
Host: alto.example.com
Accept: application/alto-cdnifci+json,
application/alto-error+json
HTTP/1.1 200 OK
Content-Length: XXX
Content-Type: application/alto-cdnifci+json
{
"meta" : {
"vtag": {
"resource-id": "my-default-cdnifci",
"tag": "da65eca2eb7a10ce8b059740b0b2e3f8eb1d4785"
}
},
"cdni-fci": {
"capabilities": [
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"http/1.1"
]
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},
"footprints": [
<Footprint objects>
]
},
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"https/1.1",
"http/1.1"
]
},
"footprints": [
<Footprint objects>
]
},
{
"capability-type": "FCI.AcquisitionProtocol",
"capability-value": {
"acquisition-protocols": [
"https/1.1"
]
},
"footprints": [
<Footprint objects>
]
}
]
}
}
3.7.3. Incremental Updates Example
A benefit of using ALTO to provide CDNI FCI resources is that such
resources can be updated using ALTO incremental updates. Below is an
example that also shows the benefit of having both JSON merge patch
and JSON patch to encode updates.
At first, an ALTO client requests updates for "my-default-cdnifci",
and the ALTO server returns the "control-uri" followed by the full
CDNI FCI response. Then when there is a change in the delivery-
protocols in that `http/1.1` is removed (from http/1.1 and https/1.1
to only https/1.1) due to maintenance of the https/1.1 clusters, the
ALTO server uses JSON merge patch to encode the change and pushes the
change to the ALTO client. Later on, the ALTO server notifies the
ALTO client that "192.0.2.0/24" is added into the "ipv4" footprint
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object for delivery-protocol https/1.1 by sending the change encoded
by JSON patch to the ALTO client.
POST /updates/cdnifci HTTP/1.1
Host: alto.example.com
Accept: text/event-stream,application/alto-error+json
Content-Type: application/alto-updatestreamparams+json
Content-Length: ###
{ "add": {
"my-cdnifci-stream": {
"resource-id": "my-default-cdnifci"
}
}
HTTP/1.1 200 OK
Connection: keep-alive
Content-Type: text/event-stream
event: application/alto-updatestreamcontrol+json
data: {"control-uri":
data: "http://alto.example.com/updates/streams/3141592653589"}
event: application/alto-cdnifci+json,my-default-cdnifci
data: { ... full CDNI FCI map ... }
event: application/merge-patch+json,my-default-cdnifci
data: {
data: "meta": {
data: "vtag": {
data: "tag": "dasdfa10ce8b059740bddsfasd8eb1d47853716"
data: }
data: },
data: "cdni-fci": {
data: "capabilities": [
data: {
data: "capability-type": "FCI.DeliveryProtocol",
data: "capability-value": {
data: "delivery-protocols": [
data: "https/1.1"
data: ]
data: },
data: "footprints": [
data: <Footprint objects in only https/1.1>
data: ]
data: }
data: ]
data: }
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data: }
event: application/json-patch+json,my-default-cdnifci
data: [
data: { "op": "replace",
data: "path": "/meta/vtag/tag",
data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
data: },
data: { "op": "add",
data: "path":
data: "/cdni-fci/capabilities/1/footprints/0/footprint-value/-",
data: "value": "192.0.2.0/24"
data: }
data: ]
4. CDNI FCI Service using ALTO Network Map
4.1. Network Map Footprint Type: altopid
The ALTO protocol defines a concept called PID to represent a group
of IPv4 or IPv6 addresses which can be applied the same management
policy. The PID is an alternative to the pre-defined CDNI footprint
types (i.e., ipv4cidr, ipv6cidr, asn, and countrycode).
Specifically, a CDNI FCI resource can depend on an ALTO network map
resource and use a new CDNI Footprint Type called "altopid" to
compress its CDNI Footprint Payload.
Specifically, the "altopid" footprint type indicates that the
corresponding footprint value is a list of PIDNames as defined in
[RFC7285]. These PIDNames are references of PIDs in a network map
resource. Hence a CDNI FCI with "altopid" footprints depends on a
network map. For such a CDNI FCI map, the resource id of its
dependent network map MUST be included in the "uses" field of its IRD
entry, and the "dependent-vtag" field with a reference to this
network map MUST be included in its response (see the example in
Section 4.2.3).
4.2. Examples
4.2.1. IRD Example
The examples below use the same IRD given in Section 3.7.1.
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4.2.2. ALTO Network Map for CDNI FCI Footprints Example
Below is an example network map whose resource id is "my-eu-netmap",
and this map is referenced by the CDNI FCI example in Section 4.2.3.
GET /networkmap HTTP/1.1
Host: http://alto.example.com/myeunetmap
Accept: application/alto-networkmap+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: XXX
Content-Type: application/alto-networkmap+json
{
"meta" : {
"vtag": [
{"resource-id": "my-eu-netmap",
"tag": "3ee2cb7e8d63d9fab71b9b34cbf764436315542e"
}
]
},
"network-map" : {
"south-france" : {
"ipv4" : [ "192.0.2.0/24", "198.51.100.0/25" ]
},
"germany" : {
"ipv4" : [ "192.0.3.0/24"]
}
}
}
4.2.3. ALTO PID Footprints in CDNI FCI
This example shows a CDNI FCI resource that depends on a network map
described in Section 4.2.2.
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GET /networkcdnifci HTTP/1.1
Host: alto.example.com
Accept: application/alto-cdnifci+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: 618
Content-Type: application/alto-cdnifci+json
{
"meta" : {
"dependent-vtags" : [
{
"resource-id": "my-eu-netmap",
"tag": "3ee2cb7e8d63d9fab71b9b34cbf764436315542e"
}
]
},
"cdni-fci": {
"capabilities": [
{ "capability-type": "FCI.DeliveryProtocol",
"capability-value": [
"http/1.1"
]
},
{ "capability-type": "FCI.DeliveryProtocol",
"capability-value": [
"https/1.1"
],
"footprints": [
{ "footprint-type": "altopid",
"footprint-value": [
"germany",
"south-france"
]
}
]
}
]
}
}
4.2.4. Incremental Updates Example
In this example, the ALTO client is interested in changes of "my-
cdnifci-with-pid-footprints". Considering two changes, the first one
is to change footprints of http/1.1 Delivery Protocol capability, and
the second one is to remove "south-france" from the footprints of
https/1.1 delivery protocol capability.
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POST /updates/cdnifci HTTP/1.1
Host: alto.example.com
Accept: text/event-stream,application/alto-error+json
Content-Type: application/alto-updatestreamparams+json
Content-Length: ###
{ "add": {
"my-network-map-cdnifci-stream": {
"resource-id": "my-cdnifci-with-pid-footprints"
}
}
HTTP/1.1 200 OK
Connection: keep-alive
Content-Type: text/event-stream
event: application/alto-updatestreamcontrol+json
data: {"control-uri":
data: "http://alto.example.com/updates/streams/3141592653590"}
event: application/alto-cdnifci+json,my-fci-stream
data: { ... full CDNI FCI resource ... }
event: application/merge-patch+json,my-fci-stream
data: {
data: "meta": {
data: "dependent-vtags" : [
data: {
data: "resource-id": "my-eu-netmap",
data: "tag": "3ee2cb7e8d63d9fab71b9b34cbf764436315542e"
data: }
data: ],
data: "vtag": {
data: "tag": "dasdfa10ce8b059740bddsfasd8eb1d47853716"
data: }
data: },
data: {
data: "capability-type": "FCI.DeliveryProtocol",
data: "capability-value": {
data: "delivery-protocols": [
data: "http/1.1"
data: ]
data: },
data: "footprints": [
data: <All footprint objects in http/1.1>
data: ]
data: }
data: }
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event: application/json-patch+json,my-fci-stream
data: [
data: {
data: "op": "replace",
data: "path": "/meta/vtag/tag",
data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
data: },
data: { "op": "remove",
data: "path": "/cdni-fci/capabilities/2/footprints/0/
data: footprint-value/1",
data: }
data: ]
5. Filtered CDNI FCI using Capabilities
Section 3 and Section 4 describe CDNI FCI Service which can be used
to enable a uCDN to get capabilities with footprints constraints from
dCDNs. However, since always getting full CDNI FCI resources from
dCDNs is inefficient, this document introduces a new service named
"Filtered CDNI FCI Service", to allow a client to filter a CDNI FCI
resource using a client-given set of capabilities. For each entry of
the CDNI FCI response, an entry will only be returned to the client
if it contains at least one of the client given capabilities. The
relationship between a filtered CDNI FCI resource and a CDNI FCI
resource is similar to the relationship between a filtered network/
cost map and a network/cost map.
5.1. Media Type
A filtered CDNI FCI resource uses the same media type defined for the
CDNI FCI resource in Section 3.1.
5.2. HTTP Method
A filtered CDNI FCI resource is requested using the HTTP POST method.
5.3. Accept Input Parameters
The input parameters for a filtered CDNI FCI resource 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-cdnifcifilter+json" which is a JSON object of type
ReqFilteredCDNIFCI, where:
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object {
JSONString capability-type;
JSONValue capability-value;
} CDNIFCICapability;
object {
[CDNIFCICapability cdni-fci-capabilities<0..*>;]
} ReqFilteredCDNIFCI;
with fields:
capability-type: The same as Base Advertisement Object's capability-
type defined in Section 5.1 of [RFC8008].
capability-value: The same as Base Advertisement Object's
capability-value defined in Section 5.1 of [RFC8008].
cdni-fci-capabilities: A list of CDNI FCI capabilities defined in
Section 5.1 of [RFC8008] for which footprints are to be returned.
If a list is empty or not appearing, the ALTO server MUST
interpret it as a request for the full CDNI FCI resource. The
ALTO server MUST interpret entries appearing in a list multiple
times as if they appeared only once. If the ALTO server does not
define any footprints for a CDNI capability, it MUST omit this
capability from the response.
5.4. Capabilities
None.
5.5. Uses
The resource ID of the CDNI FCI resource based on which the filtering
is performed.
5.6. Response
The response MUST indicate an error, using ALTO protocol error
handling specified in Section 8.5 of the ALTO protocol [RFC7285], if
the request is invalid.
Specifically, a filtered CDNI FCI request is invalid if:
o the value of "capability-type" is null;
o the value of "capability-value" is null;
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o the value of "capability-value" is inconsistent with "capability-
type".
When a request is invalid, the ALTO server MUST return an
"E_INVALID_FIELD_VALUE" error defined in Section 8.5.2 of [RFC7285],
and the "value" field of the error message SHOULD indicate this CDNI
FCI capability.
The ALTO server returns a filtered CDNI FCI resource for a valid
request. The format of a filtered CDNI FCI resource is the same as a
full CDNI FCI resource (See Section 3.6.)
The returned CDNI FCI resource MUST contain only
BaseAdvertisementObject objects whose CDNI capability object is the
superset of one of CDNI capability object in "cdni-fci-capabilities".
Specifically, that a CDNI capability object A is the superset of
another CDNI capability object B means that these two CDNI capability
objects have the same capability type and mandatory properties in
capability value of A MUST include mandatory properties in capability
value of B semantically. See Section 5.7.2 for a concrete example.
The version tag included in the "vtag" field of the response MUST
correspond to the full CDNI FCI resource from which the filtered CDNI
FCI resource is provided. This ensures that a single, canonical
version tag is used independently of any filtering that is requested
by an ALTO client.
5.7. Examples
5.7.1. IRD Example
The examples below use the same IRD example as in Section 3.7.1.
5.7.2. Basic Example
This example filters the full CDNI FCI resource in Section 3.7.2 by
selecting only the http/1.1 delivery protocol capability. Only the
first two BaseAdvertisementObjects in the full resource will be
returned because the first object's capability is http/1.1 delivery
protocol and the second object's capability is http/1.1 and https/1.1
delivery protocols which is the superset of http/1.1 delivery
protocol.
POST /cdnifci/filtered HTTP/1.1
HOST: alto.example.com
Content-Type: application/cdnifilter+json
Accept: application/alto-cdnifci+json
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{
"cdni-fci-capabilities": [
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"http/1.1"
]
}
}
]
}
HTTP/1.1 200 OK
Content-Length: XXX
Content-Type: application/alto-cdnifci+json
{
"meta" : {
"vtag": {
"resource-id": "my-default-cdnifci",
"tag": "da65eca2eb7a10ce8b059740b0b2e3f8eb1d4785"
}
},
"cdni-fci": {
"capabilities": [
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"http/1.1"
]
},
"footprints": [
<Footprint objects>
]
},
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"https/1.1",
"http/1.1"
]
},
"footprints": [
<Footprint objects>
]
}
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]
}
}
5.7.3. Incremental Updates Example
In this example, the ALTO client only cares about the updates of one
Delivery Protocol object whose value is "http/1.1". So it adds its
limitation of capabilities in "input" field of the POST request.
POST /updates/cdnifci HTTP/1.1
Host: fcialtoupdate.example.com
Accept: text/event-stream,application/alto-error+json
Content-Type: application/alto-updatestreamparams+json
Content-Length: ###
{ "add": {
"my-fci-stream": {
"resource-id": "my-filtered-cdnifci",
"input": {
"cdni-fci-capabilities": [
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"http/1.1"
]
}
}
]
}
}
}
}
HTTP/1.1 200 OK
Connection: keep-alive
Content-Type: text/event-stream
event: application/alto-updatestreamcontrol+json
data: {"control-uri":
data: "http://alto.example.com/updates/streams/3141592653590"}
event: application/alto-cdnifci+json,my-fci-stream
data: { ... full filtered CDNI FCI resource ... }
event: application/merge-patch+json,my-fci-stream
data: {
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data: "meta": {
data: "vtag": {
data: "tag": "dasdfa10ce8b059740bddsfasd8eb1d47853716"
data: }
data: },
data: {
data: "capability-type": "FCI.DeliveryProtocol",
data: "capability-value": {
data: "delivery-protocols": [
data: "http/1.1"
data: ]
data: },
data: "footprints": [
data: <All footprint objects in http/1.1>
data: ]
data: }
data: }
event: application/json-patch+json,my-fci-stream
data: [
data: {
data: "op": "replace",
data: "path": "/meta/vtag/tag",
data: "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
data: },
data: { "op": "add",
data: "path": "/cdni-fci/capabilities/0/footprints/-",
data: "value": "ipv4:192.0.2.0/24"
data: }
data: ]
6. Query Footprint Properties using ALTO Property Map Service
Besides the requirement of retrieving footprints of given
capabilities, another common requirement for uCDN is to query CDNI
capabilities of given footprints.
Considering each footprint as an entity with properties including
CDNI capabilities, a natural way to satisfy this requirement is to
use the ALTO property map as defined in
[I-D.ietf-alto-unified-props-new]. This section describes how ALTO
clients look up properties for individual footprints. First, it
describes how to represent footprint objects as entities in the ALTO
property map. Second, it provides examples of the full property map
and the filtered property map supporting CDNI capabilities, and their
incremental updates.
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6.1. Representing Footprint Objects as Property Map Entities
A footprint object has two properties: footprint-type and footprint-
value. A footprint-value is an array of footprint values conforming
to the specification associated with the registered footprint type
("ipv4cidr", "ipv6cidr", "asn", and "countrycode"). Considering each
ALTO entity defined in [I-D.ietf-alto-unified-props-new] also has two
properties: entity domain type and domain-specific identifier, a
straightforward approach to represent a footprint as an ALTO entity
is to regard its footprint-type as an entity domain type, and its
footprint value as a domain-specific identifier. According to
[I-D.ietf-alto-unified-props-new], "ipv4" and "ipv6" are two
predefined entity domain types, which can be used to represent
"ipv4cidr" and "ipv6cidr" footprints respectively. However, no
existing entity domain type can represent "asn" and "countrycode"
footprints. To represent footprint-type "asn" and "countrycode",
this document registers two new domains in Section 7 in addition to
the ones in [I-D.ietf-alto-unified-props-new].
Here is an example of representing a footprint object as a set of
entities in the ALTO property map.
{"footprint-type": "ipv4cidr", "footprint-value": ["192.0.2.0/24",
"198.51.100.0/24"]} --> "ipv4:192.168.2.0/24", "ipv4:198.51.100.0/24"
6.1.1. ASN Domain
The ASN domain associates property values with Autonomous Systems in
the Internet.
6.1.1.1. Entity Domain Type
asn
6.1.1.2. Domain-Specific Entity Identifiers
The entity identifier of an entity in an asn domain is encoded as a
string consisting of the characters "as" (in lowercase) followed by
the Autonomous System Number [RFC6793].
6.1.1.3. Hierarchy and Inheritance
There is no hierarchy or inheritance for properties associated with
ASN.
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6.1.2. COUNTRYCODE Domain
The COUNTRYCODE domain associates property values with countries.
6.1.2.1. Entity Domain Type
countrycode
6.1.2.2. Domain-Specific Entity Identifiers
The entity identifier of an entity in a countrycode domain is encoded
as an ISO 3166-1 alpha-2 code [ISO3166-1] in lowercase.
6.1.2.3. Hierarchy and Inheritance
There is no hierarchy or inheritance for properties associated with
country codes.
6.2. Examples
6.2.1. IRD Example
The examples use the same IRD example given by Section 3.7.1.
6.2.2. Property Map Example
This example shows a full property map in which entities are
footprints and entities' property is "cdni-fci-capabilities".
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GET /propmap/full/cdnifci 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": {
"meta": {
"dependent-vtags": [
{"resource-id": "my-default-cdnifci",
"tag": "7915dc0290c2705481c491a2b4ffbec482b3cf62"}
]
},
"countrycode:us": {
"my-default-cdnifci.cdni-fci-capabilities": [
{"capability-type": "FCI.DeliveryProtocol",
"capability-value": {"delivery-protocols": ["http/1.1"]}}]
},
"ipv4:192.0.2.0/24": {
"my-default-cdnifci.cdni-fci-capabilities": [
{"capability-type": "FCI.DeliveryProtocol",
"capability-value": {"delivery-protocols": ["http/1.1"]}}]
},
"ipv4:198.51.100.0/24": {
"my-default-cdnifci.cdni-fci-capabilities": [
{"capability-type": "FCI.DeliveryProtocol",
"capability-value": {"delivery-protocols": ["http/1.1"]}}]
},
"ipv6:2001:db8::/32": {
"my-default-cdnifci.cdni-fci-capabilities": [
{"capability-type": "FCI.DeliveryProtocol",
"capability-value": {"delivery-protocols": ["http/1.1"]}}]
},
"asn:as64496": {
"my-default-cdnifci.cdni-fci-capabilities": [
{"capability-type": "FCI.DeliveryProtocol",
"capability-value": {"delivery-protocols": ["http/1.1",
"https/1.1"]}}]
}
}
}
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6.2.3. Filtered Property Map Example
This example uses the filtered property map service to get "pid" and
"cdni-fci-capabilities" properties for two footprints
"ipv4:192.0.2.0/24" and "ipv6:2001:db8::/32".
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POST /propmap/lookup/cdnifci-pid HTTP/1.1
HOST: alto.example.com
Content-Type: application/alto-propmapparams+json
Accept: application/alto-propmap+json,application/alto-error+json
Content-Length:
{
"entities": [
"ipv4:192.0.2.0/24",
"ipv6:2001:db8::/32"
],
"properties": [ "my-default-cdnifci.cdni-fci-capabilities",
"my-default-networkmap.pid" ]
}
HTTP/1.1 200 OK
Content-Length: ###
Content-Type: application/alto-propmap+json
{
"property-map": {
"meta": {
"dependent-vtags": [
{"resource-id": "my-default-cdnifci",
"tag": "7915dc0290c2705481c491a2b4ffbec482b3cf62"},
{"resource-id": "my-default-networkmap",
"tag": "7915dc0290c2705481c491a2b4ffbec482b3cf63"}
]
},
"ipv4:192.0.2.0/24": {
"my-default-cdnifci.cdni-fci-capabilities": [
{"capability-type": "FCI.DeliveryProtocol",
"capability-value": {"delivery-protocols": ["http/1.1"]}}],
"my-default-networkmap.pid": "pid1"
},
"ipv6:2001:db8::/32": {
"my-default-cdnifci.cdni-fci-capabilities": [
{"capability-type": "FCI.DeliveryProtocol",
"capability-value": {"delivery-protocols": ["http/1.1"]}}],
"my-default-networkmap.pid": "pid3"
}
}
}
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6.2.4. Incremental Updates Example
In this example, here is a client want to request updates for the
properties "cdni-fci-capabilities" and "pid" for two footprints
"ipv4:192.0.2.0/24" and "countrycode:fr".
POST /updates/properties HTTP/1.1
Host: alto.example.com
Accept: text/event-stream,application/alto-error+json
Content-Type: application/alto-updatestreamparams+json
Content-Length: ###
{ "add": {
"property-map-including-capability-property": {
"resource-id": "filtered-cdnifci-property-map",
"input": {
"properties": [ "my-default-cdnifci.cdni-fci-capabilities",
"my-default-networkmap.pid" ],
"entities": [
"ipv4:192.0.2.0/24",
"ipv6:2001:db8::/32"
]
}
}
}
HTTP/1.1 200 OK
Connection: keep-alive
Content-Type: text/event-stream
event: application/alto-updatestreamcontrol+json
data: {"control-uri":
data: "http://alto.example.com/updates/streams/1414213562373"}
event: application/alto-cdnifci+json,my-fci-stream
data: { ... full filtered unified property map ... }
event: application/merge-patch+json,my-fci-stream
data: {
data: "property-map":
data: {
data: "meta": {
data: "dependent-vtags": [
data: {"resource-id": "my-default-cdnifci",
data: "tag": "2beeac8ee23c3dd1e98a73fd30df80ece9fa5627"},
data: {"resource-id": "my-default-networkmap",
data: "tag": "7915dc0290c2705481c491a2b4ffbec482b3cf63"}
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data: ]
data: },
data: "ipv4:192.0.2.0/24":
data: {
data: "my-default-cdnifci.cdni-fci-capabilities": [
data: {"capability-type": "FCI.DeliveryProtocol",
data: "capability-value": {
data: "delivery-protocols": ["http/1.1", "https/1.1"]}}]
data: }
data: }
data: }
event: application/json-patch+json,my-fci-stream
data: {[
data: {
data: { "op": "replace",
data: "path": "/meta/dependent-vtags/0/tag",
data: "value": "61b23185a50dc7b334577507e8f00ff8c3b409e4"
data: },
data: { "op": "replace",
data: "path":
data: "/property-map/countrycode:fr/my-default-networkmap.pid",
data: "value": "pid5"
data: }
data: }
data: ]}
7. IANA Considerations
7.1. CDNI Metadata Footprint Type Registry
As proposed in Section 7.2 of [RFC8006], "CDNI Metadata Footprint
Types" registry is requested. A new footprint type is to be
registered, listed in Table 1.
+----------------+---------------------+----------------------+
| Footprint Type | Description | Specification |
+----------------+---------------------+----------------------+
| altopid | A list of PID-names | Section 4 of RFCthis |
+----------------+---------------------+----------------------+
Table 1: CDNI Metadata Footprint Type
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
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7.2. ALTO Entity Domain Type Registry
As proposed in Section 11.2 of [I-D.ietf-alto-unified-props-new],
"ALTO Entity Domain Type Registry" is requested. Two new entity
domain types are to be registered, listed in Table 2.
+-------------+-------------------------+-------------------------+
| Identifier | Entity Address Encoding | Hierarchy & Inheritance |
+-------------+-------------------------+-------------------------+
| asn | See Section 6.1.1.2 | None |
| countrycode | See Section 6.1.2.2 | None |
+-------------+-------------------------+-------------------------+
Table 2: ALTO Entity Domain Types
7.3. ALTO Entity Property Type Registry
As proposed in Section 11.3 of [I-D.ietf-alto-unified-props-new],
"ALTO Entity Property Type Registry" is required. A new entity
property type is to be registered, listed in Table 3.
+-----------------------+-----------------------------------------+
| Identifier | Intended Semantics |
+-----------------------+-----------------------------------------+
| cdni-fci-capabilities | An array of CDNI FCI capability objects |
+-----------------------+-----------------------------------------+
Table 3: ALTO CDNI FCI Property Type
8. Security Considerations
As an extension of the base ALTO protocol ([RFC7285]), this document
fits into the architecture of the base protocol. And hence its
Security Considerations (Section 15 of [RFC7285]) fully apply when
this extension is provided by an ALTO server.
In the context of CDNI FCI, additional security considerations should
be included as follows:
For authenticity and integrity of ALTO information, an attacker may
disguise itself as an ALTO server for a dCDN, and provide false
capabilities and footprints to a uCDN using the CDNI FCI service.
Such false information may lead a uCDN to (1) select an incorrect
dCDN to serve user requests, or (2) skip uCDNs in good conditions.
For potential undesirable guidance from authenticated ALTO
information, a dCDN can provide a uCDN with limited capabilities and
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smaller footprint coverage so that the dCDN can avoid transferring
traffic for a uCDN which they should have to transfer.
For confidentiality and privacy of ALTO information, footprint
properties integrated with ALTO unified property may expose network
location identifiers (e.g., IP addresses or fine-grained PIDs).
Without access control of ALTO services, an attacker may conduct
service degradation attacks. It may request potentially large, full
CDNI FCI resources from an ALTO server in a dCDN continuously, to
consume the bandwidth resources of that ALTO server. It may also
query filtered property map services with many smaller individual
footprints, to consume the computation resources of the ALTO server.
Protection strategies as described in RFC 7285 should be applied to
address aforementioned security considerations. In addition, the
isolation of full/filtered CDNI FCI resources should also be
considered. In particular, if a dCDN signs agreements with multiple
uCDNs, it must isolate full/ filtered CDNI FCI resources for
different uCDNs in that uCDNs will not redirect requests which should
not have to be served by this dCDN to this dCDN and it may not
disclose extra information to uCDNs.
One approach to reducing the risk is that a dCDN could consider
generating URIs of different full/filtered CDNI FCI resources by
hashing its company ID, a uCDN's company ID as well as their
agreements. A dCDN SHOULD avoid exposing all full/filtered CDNI FCI
resources in one of its IRDs.
9. Acknowledgments
The authors thank Matt Caulfield, Danny Alex Lachos Perez, Daryl
Malas and Sanjay Mishra for their timely reviews and invaluable
comments. Mr. Xiao Shawn Lin is an author of an early version of
this document, with many contributions.
Jan Seedorf is partially supported by the GreenICN project (GreenICN:
Architecture and Applications of Green Information Centric
Networking), a research project supported jointly by the European
Commission under its 7th Framework Program (contract no. 608518) and
the National Institute of Information and Communications Technology
(NICT) in Japan (contract no. 167). The views and conclusions
contained herein are those of the authors and should not be
interpreted as necessarily representing the official policies or
endorsements, either expressed or implied, of the GreenICN project,
the European Commission, or NICT.
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10. References
10.1. Normative References
[ISO3166-1]
The International Organization for Standardization, "Codes
for the representation of names of countries and their
subdivisions -- Part 1: Country codes", ISO 3166-1:2013,
2013.
[RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic
Optimization (ALTO) Problem Statement", RFC 5693, DOI
10.17487/RFC5693, October 2009, <https://www.rfc-
editor.org/info/rfc5693>.
[RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
Distribution Network Interconnection (CDNI) Problem
Statement", RFC 6707, DOI 10.17487/RFC6707, September
2012, <https://www.rfc-editor.org/info/rfc6707>.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793, DOI
10.17487/RFC6793, December 2012, <https://www.rfc-
editor.org/info/rfc6793>.
[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>.
[RFC8006] Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
"Content Delivery Network Interconnection (CDNI)
Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
<https://www.rfc-editor.org/info/rfc8006>.
[RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
R., and K. Ma, "Content Delivery Network Interconnection
(CDNI) Request Routing: Footprint and Capabilities
Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
<https://www.rfc-editor.org/info/rfc8008>.
10.2. Informative References
[I-D.ietf-alto-incr-update-sse]
Roome, W. and Y. Yang, "ALTO Incremental Updates Using
Server-Sent Events (SSE)", draft-ietf-alto-incr-update-
sse-20 (work in progress), February 2020.
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[I-D.ietf-alto-path-vector]
Gao, K., Lee, Y., Randriamasy, S., Yang, Y., and J. Zhang,
"ALTO Extension: Path Vector", draft-ietf-alto-path-
vector-09 (work in progress), November 2019.
[I-D.ietf-alto-unified-props-new]
Roome, W., Randriamasy, S., Yang, Y., Zhang, J., and K.
Gao, "Unified Properties for the ALTO Protocol", draft-
ietf-alto-unified-props-new-10 (work in progress),
November 2019.
[RFC7975] Niven-Jenkins, B., Ed. and R. van Brandenburg, Ed.,
"Request Routing Redirection Interface for Content
Delivery Network (CDN) Interconnection", RFC 7975, DOI
10.17487/RFC7975, October 2016, <https://www.rfc-
editor.org/info/rfc7975>.
Authors' Addresses
Jan Seedorf
HFT Stuttgart - Univ. of Applied Sciences
Schellingstrasse 24
Stuttgart 70174
Germany
Phone: +49-0711-8926-2801
Email: jan.seedorf@hft-stuttgart.de
Y.R. Yang
Yale University/PCL
51 Prospect Street
New Haven, CT 06511
United States of America
Email: yry@cs.yale.edu
URI: http://www.cs.yale.edu/~yry/
Kevin J. Ma
Ericsson
43 Nagog Park
Acton, MA 01720
United States of America
Phone: +1-978-844-5100
Email: kevin.j.ma.ietf@gmail.com
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Jon Peterson
NeuStar
1800 Sutter St Suite 570
Concord, CA 94520
United States of America
Email: jon.peterson@neustar.biz
Jingxuan Jensen Zhang
Tongji University
4800 Cao'an Hwy
Shanghai 201804
China
Email: jingxuan.zhang@tongji.edu.cn
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