CDNI J. Seedorf
Internet-Draft HFT Stuttgart - Univ. of Applied Sciences
Intended status: Standards Track Y. Yang
Expires: July 25, 2020 Tongji/Yale
K. Ma
Ericsson
J. Peterson
Neustar
X. Lin
J. Zhang
Tongji
January 22, 2020
Content Delivery Network Interconnection (CDNI) Request Routing: CDNI
Footprint and Capabilities Advertisement using ALTO
draft-ietf-alto-cdni-request-routing-alto-09
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. In this document, we follow the
guidelines to define an FCI protocol using the Application-Layer
Traffic Optimization (ALTO) protocol.
Status of This Memo
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provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 25, 2020.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. 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 . . . . . . . . . . . . . . . . . . . . . . . 9
3.3. Accept Input Parameters . . . . . . . . . . . . . . . . . 9
3.4. Capabilities . . . . . . . . . . . . . . . . . . . . . . 9
3.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.6. Response . . . . . . . . . . . . . . . . . . . . . . . . 9
3.7. Examples . . . . . . . . . . . . . . . . . . . . . . . . 11
3.7.1. IRD Example . . . . . . . . . . . . . . . . . . . . . 12
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 . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2.1. IRD Example . . . . . . . . . . . . . . . . . . . . . 18
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 . . . . . . . . . . . . . 31
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33
7.1. CDNI Metadata Footprint Type Registry . . . . . . . . . . 33
7.2. ALTO Entity Domain Type Registry . . . . . . . . . . . . 33
7.3. ALTO Entity Property Type Registry . . . . . . . . . . . 34
8. Security Considerations . . . . . . . . . . . . . . . . . . . 34
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 35
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.1. Normative References . . . . . . . . . . . . . . . . . . 35
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
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) CDNI Footprint & Capabilities
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Advertisement interface (FCI), and (2) CDNI Request Routing
Redirection interface (RI). Since this document focuses on the first
functionality, CDNI FCI, we will describe it in a more detailed way.
CDNI FCI is an advertisement from a dCDN to a uCDN (push) or 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
we discuss 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 a 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 huge. 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 some footprints in which
it is interested. IANA and security considerations are discussed in
Section 7 and Section 8 respectively.
Throughout this document, we use the terminologies for CDNI defined
in [RFC6707], [RFC8006], [RFC8008] and we use the terminologies for
ALTO defined in [RFC7285], [I-D.ietf-alto-unified-props-new].
2. Background
The design of CDNI FCI transport using ALTO depends on the
understanding of both FCI semantics and ALTO. Hence, we start with a
review of both.
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2.1. Semantics of FCI Advertisement
The CDNI document on "Footprint and Capabilities Semantics" [RFC8008]
defines the semantics of CDNI FCI, and provides guidance on what
Footprint and Capabilities mean in a CDNI context and how a protocol
solution should in principle look. The definitions in [RFC8008]
depend on [RFC8006]. Here we briefly summarize key related points of
[RFC8008] and [RFC8006]. For a detailed discussion, the reader is
referred to the RFCs.
o Footprint and capabilities are tied together and cannot be
interpreted independently from each other. Hence, capabilities
must be expressed on a per footprint basis. [RFC8008] integrates
footprint and capabilities with an approach of "capabilities with
footprint restrictions".
o Given that a large part of Footprint and Capabilities
Advertisement will 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 request routing interface. 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 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.
o Multiple types of footprints (ipv4cidr, ipv6cidr, asn, and
countrycode) are defined in [RFC8006].
o 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 For all of these 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
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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.
o The following capabilities are defined as "base" capabilities;
that is, 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
2.2. ALTO Background and Benefits
Application-Layer Traffic Optimization (ALTO) [RFC7285] is an
approach for guiding the resource provider selection process in
distributed applications that can choose among several candidate
resources providers to retrieve a given resource. By conveying
network layer (topology) information, an ALTO server can provide
important information to "guide" the resource provider selection
process in distributed applications. 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]. Recently, however, ALTO is
also being considered for improving the request routing in CDNs
[I-D.jenkins-alto-cdn-use-cases]. The CDNI problem statement
explicitly mentions ALTO as a candidate protocol for "actual
algorithms for selection of CDN or Surrogate by Request-Routing
systems" [RFC6707].
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
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. For
CDNI, this is exactly the case: a uCDN wants to improve
application layer CDN request routing by using dedicated
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information (provided by a dCDN) that the uCDN could not easily
obtain otherwise. 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
if such a footprint is being expressed by IP-prefix ranges.
Please see Section 4.
o Security: Identifications between uCDNs and dCDNs are extremely
important. 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 has undergone extensive
revisions in order to provide sophisticated error-handling, in
particular regarding unexpected cases. A CDNI FCI interface based
on ALTO would inherit this thought-through and mature error-
handling. 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,
filtered property map service can enable a uCDN to query
properties of a part of footprints in an effective way (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 directly inform a uCDN about such changes.
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 very recent network and
cost map from dCDN, and therefore redirect requests to 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].
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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 if a given dCDN actually has the capabilities for a
given request with respect to the type of content requested.
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".
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3.2. HTTP Method
A CDNI FCI resource is requested using the HTTP GET method.
3.3. Accept Input Parameters
None.
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.
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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].
To be self-contained, we give a non-normative specification of
BaseAdvertisementObject below. 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>
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]
},
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"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
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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.
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" : {
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"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": [
"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" :
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"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",
"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
In this example, we demonstrate a simple CDNI FCI resource; this
resource 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"
}
},
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"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>
]
},
{
"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.
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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
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"
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data: ]
data: },
data: "footprints": [
data: <Footprint objects in only https/1.1>
data: ]
data: }
data: ]
data: }
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.
"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).
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4.2. Examples
4.2.1. IRD Example
We use the same IRD example given in Section 3.7.1.
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
In this example, we show a CDNI FCI resource that depends on a
network map described in Section 4.2.2.
GET /networkcdnifci HTTP/1.1
Host: alto.example.com
Accept: application/alto-cdnifci+json,application/alto-error+json
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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.
POST /updates/cdnifci HTTP/1.1
Host: alto.example.com
Accept: text/event-stream,application/alto-error+json
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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: }
event: application/json-patch+json,my-fci-stream
data: [
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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, always getting full CDNI FCI resources from dCDNs is
very inefficient, hence we introduce 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
an 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
We use the same IRD example by 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 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, the most natrual way to satisfy this requirement
is to use the ALTO property map defined in
[I-D.ietf-alto-unified-props-new].
In this section, we describe how ALTO clients look up properties for
individual footprints. We firstly describe how to represent
footprint objects as entities in the ALTO property map. And then we
provide 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 identifiers of entities 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 identifiers of entities 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
We 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
In this example, we use 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".
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" ]
}
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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"
}
}
}
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": [
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"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"}
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",
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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
registred, listed in Table 1.
+-------------------+-----------------------+-----------------------+
| Footprint Type | Description | Specification |
+-------------------+-----------------------+-----------------------+
| altopid | A list | Section 4 of RFCthis |
| | of PID-names | |
+-------------------+-----------------------+-----------------------+
Table 1: CDNI Metadata Footprint Type
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
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 | Hierarchy & |
| | Address Encoding | Inheritance |
+-----------------+------------------------+------------------------+
| asn | See | None |
| | Section 6.1.1.2 | |
| countrycode | See | None |
| | Section 6.1.2.2 | |
+-----------------+------------------------+------------------------+
Table 2: ALTO Entity Domain Types
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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 registred, listed in Table 3.
+-----------------------------+-------------------------------------+
| Identifier | Intended Semantics |
+-----------------------------+-------------------------------------+
| cdni-fci- | An array of CDNI FCI |
| capabilities | 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 the
Security Considerations (Section 15) of the base protocol 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, dCDNs can provide a uCDN with limited capabilities and
smaller footprint coverage so that dCDNs 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).
For availability of ALTO services, an attacker may get the potential
huge full CDNI FCI resources from an ALTO server in a dCDN
continuously to unnecessarily consume bandwidth resources of that
ALTO server or may query filtered CDNI FCI services with complex
capabilities to unnecessarily consume computation resources of an
ALTO server.
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Protection strategies described in RFC 7285 can solve problems
mentioned above, however, the isolation of full/filtered CDNI FCI
resources should also be considered.
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.
To avoid this risk, 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
expoing all full/filtered CDNI FCI resources in one of its IRDs.
9. Acknowledgments
The authors would like to thank Daryl Malas, Matt Caulfield for their
timely reviews and invaluable comments.
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.
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>.
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[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-17 (work in progress), July 2019.
[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-08 (work in progress), July 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-09 (work in progress),
September 2019.
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[I-D.jenkins-alto-cdn-use-cases]
Niven-Jenkins, B., Watson, G., Bitar, N., Medved, J., and
S. Previdi, "Use Cases for ALTO within CDNs", draft-
jenkins-alto-cdn-use-cases-03 (work in progress), June
2012.
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
Tongji/Yale University
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
Jon Peterson
NeuStar
1800 Sutter St Suite 570
Concord, CA 94520
United States of America
Email: jon.peterson@neustar.biz
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Xiao Shawn Lin
Tongji University
4800 Cao'an Hwy
Shanghai 201804
China
Email: x.shawn.lin@gmail.com
Jingxuan Jensen Zhang
Tongji University
4800 Cao'an Hwy
Shanghai 201804
China
Email: jingxuan.zhang@tongji.edu.cn
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