Internet DRAFT - draft-ma-cdni-capabilities
draft-ma-cdni-capabilities
Network Working Group K. Ma
Internet-Draft Ericsson
Intended status: Standards Track J. Seedorf
Expires: October 24, 2016 NEC
April 22, 2016
CDNI Footprint & Capabilities Advertisement Interface
draft-ma-cdni-capabilities-09
Abstract
Content Distribution Network Interconnection (CDNI) is predicated on
the ability of downstream CDNs (dCDNs) to handle end-user requests in
a functionally equivalent manner to the upstream CDN (uCDN). The
uCDN must be able to assess the ability of the dCDN to handle
individual requests. The CDNI Footprint & Capabilities Advertisement
interface (FCI) is provided for the advertisement of capabilities and
the footprints to which they apply by the dCDN to the uCDN. This
document describes an approach to implementing the CDNI FCI.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 24, 2016.
Ma & Seedorf Expires October 24, 2016 [Page 1]
Internet-Draft CDNI FCI April 2016
Copyright Notice
Copyright (c) 2016 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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. CDNI FCI Capability Advertisement . . . . . . . . . . . . . . 4
2.1. CDNI FCI Capability Initialization . . . . . . . . . . . 5
3. CDNI FCI Capabilities Service . . . . . . . . . . . . . . . . 5
3.1. CDNI FCI Map . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1. Media Type . . . . . . . . . . . . . . . . . . . . . 5
3.1.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . 5
3.1.3. Accept Input Parameters . . . . . . . . . . . . . . . 6
3.1.4. Capabilities . . . . . . . . . . . . . . . . . . . . 6
3.1.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.6. Response . . . . . . . . . . . . . . . . . . . . . . 6
3.1.7. CDNI FCI Capabilities . . . . . . . . . . . . . . . . 7
3.1.7.1. Delivery Protocol . . . . . . . . . . . . . . . . 7
3.1.7.2. Acquisition Protocol . . . . . . . . . . . . . . 9
3.1.7.3. Redirection Mode . . . . . . . . . . . . . . . . 11
3.1.7.4. Logging Capabilities . . . . . . . . . . . . . . 13
3.1.7.5. Metadata Capabilities . . . . . . . . . . . . . . 14
4. CDNI FCI Capabilities Filtering Service . . . . . . . . . . . 15
4.1. Filtered CDNI FCI Map . . . . . . . . . . . . . . . . . . 15
4.1.1. Media Type . . . . . . . . . . . . . . . . . . . . . 15
4.1.2. HTTP Method . . . . . . . . . . . . . . . . . . . . . 15
4.1.3. Accept Input Parameters . . . . . . . . . . . . . . . 15
4.1.4. Capabilities . . . . . . . . . . . . . . . . . . . . 15
4.1.5. Uses . . . . . . . . . . . . . . . . . . . . . . . . 15
4.1.6. Response . . . . . . . . . . . . . . . . . . . . . . 16
4.1.7. Example . . . . . . . . . . . . . . . . . . . . . . . 16
5. Footprint via ALTO Network Map . . . . . . . . . . . . . . . 16
5.1. ALTO Network Maps . . . . . . . . . . . . . . . . . . . . 16
5.2. Example ALTO Network Map for CDNI FCI Footprint . . . . . 16
5.3. Example of ALTO Network Map Footprint in FCI Map . . . . 17
Ma & Seedorf Expires October 24, 2016 [Page 2]
Internet-Draft CDNI FCI April 2016
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
6.1. ALTO Media Types . . . . . . . . . . . . . . . . . . . . 19
6.1.1. ALTO CDNI FCI Map Media Type . . . . . . . . . . . . 19
6.1.2. ALTO CDNI FCI Map Filter Media Type . . . . . . . . . 20
6.2. CDNI Footprint Types . . . . . . . . . . . . . . . . . . 22
7. Security Considerations . . . . . . . . . . . . . . . . . . . 22
7.1. Securing the CDNI Footprint & Capabilities Advertisement
interface . . . . . . . . . . . . . . . . . . . . . . . . 22
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 23
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
9.1. Normative References . . . . . . . . . . . . . . . . . . 23
9.2. Informative References . . . . . . . . . . . . . . . . . 24
Appendix A. Capability Aggregation . . . . . . . . . . . . . . . 25
A.1. Downstream CDN Aggregation . . . . . . . . . . . . . . . 25
A.2. Internal Request Router Aggregation . . . . . . . . . . . 27
A.3. Internal Capability Aggregation . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction
The need for footprint and capabilities advertisement in Content
Distribution Network Interconnection (CDNI) is described in the CDNI
requirements document [RFC7337]. Requirements FCI-1 and FCI-2
describe the need to allow dCDNs to communicate capabilities to the
uCDN. Requirement FCI-3 describes how a uCDN may aggregate the
footprint and capabilities information for all cascaded dCDNs and use
the aggregated information in advertisements to CDNs further
upstream. This concept of aggregation can apply to both
organizationally different dCDNs (e.g., other CDN providers, or
different business units within a larger organization) or logical
entities within the same CDN (e.g., using multiple request routers
for scalability reasons, to segregate surrogates based on specific
protocol support, or to segregate surrogates based on software
version or feature level, etc.).
Appendix A contains more detailed descriptions of different footprint
and capabilities management scenarios, but it is important to note
that it is the ability of the dCDN to service each request in a
functionally equivalent manner as the uCDN that is important, not the
physical layout of resources through which it services the request.
The aggregation of resource knowledge by the dCDN into a simple set
of capabilities and their affective footprints, that is then
advertised to the uCDN, enables efficient decision making at each
delegation point in the CDN interconnection hierarchy.
It is assumed that an authoritative request router in each CDN will
be responsible for aggregating and advertising capabilities
information in a dCDN and/or receiving and aggregating capabilities
Ma & Seedorf Expires October 24, 2016 [Page 3]
Internet-Draft CDNI FCI April 2016
information in the uCDN. The CDNI Footprint & Capabilities
Advertisement interface (FCI) along with the CDNI Request Routing
Redirection interface (RI) [I-D.ietf-cdni-redirection] make up the
CDNI Request Routing Interface. As there is no other centralized
CDNI controller, the authoritative request router seems the most
logical place for capabilities aggregation to occur, as it is the
request router that needs such information to make delegation
decisions. The protocol defined herein may be implemented as part of
an entity other than an authoritative request router, but for the
purposes of this discussion, the authoritative request router is
assumed to be the centralized capabilities aggregation point.
Though there is an obvious need for the ability to exchange and
update footprint and capability information in real-time, it is
assumed that capabilities do not change very often. It is also
assumed that the capabilities are not by themselves useful for making
delegation decisions. Capability information is assumed to be input
into business logic. It is the business logic which provides the
algorithms for delegation decision making. The definition of
business logic occurs outside the scope of CDNI and outside the
timescale of footprint and capability advertisement
[I-D.ietf-cdni-footprint-capabilities-semantics]. It may be the case
that the business logic anticipates and reacts to changes in dCDN
capabilities, however, it may also be the case that business logic is
tailored through offline processes as dCDN capabilities change. The
FCI is agnostic to the business processes employed by any given uCDN.
The footprints and capabilities that are advertised over the FCI may
be used by the uCDN at its discretion, to implement delegation rules.
Setting proper defaults in the business logic should prevent any
unwanted delegation from occurring when dCDN capabilities change,
however, that is beyond the scope of this discussion.
1.1. Terminology
This document uses the terminology defined in section 1.1 of the CDNI
Framework [RFC7336] document.
2. CDNI FCI Capability Advertisement
The FCI is implemented as an ALTO [RFC7285] Service. The ALTO
protocol defines an HTTP-based transport through which ALTO service
information may be retrieved using either a GET or POST method. The
uCDN request router may at any time query the dCDN ALTO FCI Service
for the full set of dCDN capability information. The uCDN may use a
separate FCI Filter Service to retrieve a subset of the dCDN
capability information.
[Ed.: Need to update this with ALTO asynchronous update support.]
Ma & Seedorf Expires October 24, 2016 [Page 4]
Internet-Draft CDNI FCI April 2016
[Ed.: Need to update this with ALTO incremental update support.]
2.1. CDNI FCI Capability Initialization
In lieu of any out-of-band pre-configured capability information,
when the FCI is first brought up between a uCDN and a dCDN, the uCDN
SHOULD assume that the dCDN has no CDNI capabilities. If an out-of-
band capability baseline has been exchanged, the uCDN MAY use that
information to initialize its capabilities database. In either case,
the uCDN SHOULD verify the initial state of the dCDN (as a temporary
outage may affect availability in the dCDN).
The dCDN MUST support sending its entire set of capabilities to the
uCDN through the ALTO service interface
3. CDNI FCI Capabilities Service
As described in Requirement FCI-2, there is a basic set of
capabilities that must be supported by the FCI for the uCDN to be
able to determine if the dCDN is functionally able to handle a given
request. [I-D.ietf-cdni-footprint-capabilities-semantics] lists
mandatory capabilities types:
o Delivery Protocol
o Acquisition Protocol
o Redirection Mode
o CDNI Logging Capabilities
o CDNI Metadata Capabilities
To be consistent with the base ALTO service definitions, we use the
JSON object definition notation as specified in the ALTO protocol
[RFC7285].
3.1. CDNI FCI Map
3.1.1. Media Type
The media type of CDNI FCI Map is "application/alto-cdni-fcimap+json"
3.1.2. HTTP Method
A CDNI FCI Map resource is requested using the HTTP GET method.
Ma & Seedorf Expires October 24, 2016 [Page 5]
Internet-Draft CDNI FCI April 2016
3.1.3. Accept Input Parameters
None.
3.1.4. Capabilities
None.
3.1.5. Uses
None.
3.1.6. Response
The data component of a CDNI FCI Map resource is named "fcimap" which
is a JSON object of type FCIMapData:
object {
FCIMapData fcimap<0..*>;
} InfoResourceFCIMap : ResponseEntityBase;
object {
FCICapability capabilities<1..*>;
} FCIMapData;
object {
JSONString capability-type;
JSONValue capability-value
FCIFootprint footprints<0..*>;
} FCICapability;
object {
JSONString footprint-type;
JSONString footprint-value<1..*>;
} FCIFootprint;
The FCIMapData object contains a CDNI Payload Type [RFC7736] "ptype"
which identifies the capability and a "value" object containing the
associated Capability Advertisement Object (e.g., delivery-protocols,
acquisition-protocols, or redirection-modes, as defined in
[I-D.ietf-cdni-footprint-capabilities-semantics]). The FCIMapData
object may also contain an optional list of FCIFootprint objects
"footprints". The FCIFootprint object specifies a "footprint-type"
(as defined by the CDNI Metadata Footprint Types registry, e.g.,
ipv4cidr, ipv6cidr, asn, or countrycode [I-D.ietf-cdni-metadata])
which identifies the contents and encoding of the individual
footprint entries contained in the associated "footprint-value"
array.
Ma & Seedorf Expires October 24, 2016 [Page 6]
Internet-Draft CDNI FCI April 2016
The "footprints" list MUST NOT contain multiple FCIFootprint objects
of the same type. Footprint restriction information MAY be specified
using multiple different footprint-types. If no footprint
restriction list is specified (or an empty list is specified), it
SHALL be understood that all footprint types MUST be reset to
"global" coverage.
Note: Further optimization of the footprint object to provide quality
information for a given footprint is certainly possible, however, it
is not necessary for the basic interconnection of CDNs. The ability
to transfer quality information in capabilities advertisements may be
desirable and is noted here for completeness, however, the specifics
of such mechanisms are outside the scope of this document.
Multiple FCIMapData objects with the same capability type are allowed
within a given CDNI FCI Map response as long as the capability option
footprint-value do not overlap, i.e., a given capability option value
MUST NOT show up in multiple FCIMapData objects within a single CDNI
FCI Map response. If multiple FCIMapData objects for a given
capability type exist, those capability objects MUST have different
footprint restrictions. Capability objects of a given capability
type with identical footprint restrictions MUST be combined into a
single capability object.
3.1.7. CDNI FCI Capabilities
3.1.7.1. Delivery Protocol
The delivery protocol refers to the protocol over which an end user
(EU) has requested content. If a dCDN does not support the protocol
requested by the client, then the dCDN is not a viable candidate for
delegation.
Though the delivery protocol is specified in the URI scheme (as
defined in [RFC3986]) of the client request URL, protocol feature
subsets or augmented protocol feature sets MAY be defined and SHOULD
correspond with the protocols listed in the CDNI Metadata Protocol
Types registry, e.g., http1.1 or https1.1 [I-D.ietf-cdni-metadata].
The following example shows two lists of delivery protocols with
different footprints.
Ma & Seedorf Expires October 24, 2016 [Page 7]
Internet-Draft CDNI FCI April 2016
GET /fcimap HTTP/1.1
Host: alto.example.com
Accept: application/alto-fcimap+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: 627
Content-Type: application/alto-fcimap+json
{
"meta" : {
},
"fcimap": {
"capabilities": [
{ "capability-type": "FCI.DeliveryProtocol"
"capability-value": {
"delivery-protocols": [
"http1.1"
]
}
},
{ "capability-type": "FCI.DeliveryProtocol"
"capability-value": {
"delivery-protocols": [
"https1.1"
]
},
"footprints": [
{ "footprint-type": "ipv4cidr",
"footprint-value": [
"10.1.0.0/16",
"10.10.10.0/24"
]
}
]
}
]
}
}
In the above example, the HTTP/1.1 protocol is supported globally,
while the HTTP/1.1 over TLS protocol is only supported in a
restricted footprint (in this case, specified by IPv4 prefix).
A given protocol MUST NOT appear in multiple FCIMapData
FCI.DeliveryProtocol object values.
Ma & Seedorf Expires October 24, 2016 [Page 8]
Internet-Draft CDNI FCI April 2016
3.1.7.2. Acquisition Protocol
The acquisition protocol refers to the protocol over which an end
user (EU) has requested content. If a dCDN does not support the
protocol requested by the client, then the dCDN is not a viable
candidate for delegation.
Though the acquisition protocol is specified in the URI scheme (as
defined in [RFC3986]) of the client request URL, protocol feature
subsets or augmented protocol feature sets MAY be defined and SHOULD
correspond with the protocols listed in the CDNI Metadata Protocol
Types registry, e.g., http1.1 or https1.1 [I-D.ietf-cdni-metadata].
The following example shows two lists of acquisition protocols with
different footprints.
Ma & Seedorf Expires October 24, 2016 [Page 9]
Internet-Draft CDNI FCI April 2016
GET /fcimap HTTP/1.1
Host: alto.example.com
Accept: application/alto-fcimap+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: 620
Content-Type: application/alto-fcimap+json
{
"meta" : {
},
"fcimap": {
"capabilities": [
{ "capability-type": "FCI.AcquisitionProtocol"
"capability-value": {
"acquisition-protocols": [
"http1.1"
]
}
},
{ "capability-type": "FCI.AcquisitionProtocol"
"capability-value": {
"acquisition-protocols": [
"https1.1"
]
},
"footprints": [
{ "footprint-type": "asn",
"footprint-value": [
"AS0",
"AS65535"
]
}
]
}
]
}
}
In the above example, the HTTP/1.1 protocol is supported globally,
while the HTTP/1.1 over TLS protocol is only supported in a
restricted footprint (in this case, specified by Autonomous System
number).
A given protocol MUST NOT appear in multiple FCIMapData
FCI.AcquisitionProtocol value objects.
Ma & Seedorf Expires October 24, 2016 [Page 10]
Internet-Draft CDNI FCI April 2016
3.1.7.3. Redirection Mode
The redirection mode refers to the method(s) employed by request
routers to perform request redirection. The CDNI framework [RFC7336]
document describes four possible request routing modes:
o DNS iterative (DNS-I)
o DNS recursive (DNS-R)
o HTTP iterative (HTTP-I)
o HTTP recursive (HTTP-R)
[I-D.ietf-cdni-footprint-capabilities-semantics] defines the "CDNI
Capabilities Redirection Modes" registry and the initial supported
redirection mode values shown in parentheses above.
If a dCDN supports only a specific mode or subset of modes that does
not overlap with the modes supported by the uCDN, then the dCDN might
not be a viable candidate for delegation.
The following example shows two lists of redirection modes with
different footprints.
Ma & Seedorf Expires October 24, 2016 [Page 11]
Internet-Draft CDNI FCI April 2016
GET /fcimap HTTP/1.1
Host: alto.example.com
Accept: application/alto-fcimap+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: 767
Content-Type: application/alto-fcimap+json
{
"meta" : {
},
"fcimap": {
"capabilities": [
{ "capability-type": "FCI.RedirectionMode",
"capability-value": {
"redirection-modes": [
"DNS-I",
"HTTP-I"
]
}
},
{ "capability-type": "FCI.RedirectionMode",
"capability-value": {
"redirection-modes": [
"DNS-R",
"HTTP-R"
]
},
"footprints": [
{ "footprint-type": "countrycode",
"footprint-value": [
"SE"
]
},
{ "footprint-type": "ipv6cidr",
"footprint-value": [
"9876:5432::1/36"
]
}
]
}
]
}
}
In the above example, iterative redirection is supported globally,
while recursive redirection is only supported in a restricted
Ma & Seedorf Expires October 24, 2016 [Page 12]
Internet-Draft CDNI FCI April 2016
footprint (in this case, specified by both Country Code and IPv6
prefix).
A given mode MUST NOT appear in multiple FCIMapData
FCI.RedirectionMode object values.
3.1.7.4. Logging Capabilities
[I-D.ietf-cdni-logging] describes the "cdni_http_request_v1" logging
record-types and optional vs. mandatory-to-implement logging fields
for that record-type. It also allows new logging record-types and
logging fields to be defined which would be optional for a dCDN to
implement.
If a dCDN does not support certain logging parameters which may
affect billing agreements or legal requirements of the uCDN, then the
dCDN is not a viable candidate for delegation.
3.1.7.4.1. CDNI Logging Capability Object Serialization
The following shows an example of CDNI Logging Capability Object
Serialization, for a CDN that supports the optional Content
Collection ID logging field (but not the optional Session ID logging
field) for the "cdni_http_request_v1" record type.
{
"capabilities": [
{
"capability-type": "FCI.Logging",
"capability-value": {
"record-type": "cdni_http_request_v1",
"fields": [ "s-ccid" ]
},
"footprints": [
<Footprint objects>
]
}
]
}
The next example shows the CDNI Logging Capability Object
Serialization, for a CDN that supports all optional fields for the
"cdni_http_request_v1" record type.
Ma & Seedorf Expires October 24, 2016 [Page 13]
Internet-Draft CDNI FCI April 2016
{
"capabilities": [
{
"capability-type": "FCI.Logging",
"capability-value": {
"record-type": "cdni_http_request_v1"
},
"footprints": [
<Footprint objects>
]
}
]
}
3.1.7.5. Metadata Capabilities
[I-D.ietf-cdni-metadata] describes GenericMetadata types which may be
optional for a dCDN to implement, but which, if present, are
mandatory-to-enforce. It also allows for new GenericMetadata to be
defined which would be optional for a dCDN to implement.
If a dCDN does not support certain GenericMetadata types which are
designated mandatory-to-enforce and may affect the correctness or
security of the content being delivered, then the dCDN is not a
viable candidate for delegation.
3.1.7.5.1. CDNI Metadata Capability Object Serialization
The following shows an example of CDNI Metadata Capability Object
Serialization, for a CDN that supports only the SourceMetadata
GenericMetadata type (i.e., it can acquire and deliver content, but
cannot enforce and security policies, e.g., time, location, or
protocol ACLs).
{
"capabilities": [
{
"capability-type": "FCI.Metadata",
"capability-value": {
"metadata": ["MI.SourceMetadata"]
},
"footprints": [
<Footprint objects>
]
}
]
}
Ma & Seedorf Expires October 24, 2016 [Page 14]
Internet-Draft CDNI FCI April 2016
The next example shows the CDNI Metadata Capability Object
Serialization, for a CDN that supports only structural metadata
(i.e., it can parse metadata as a transit CDN, but cannot enforce
security policies or deliver content).
{
"capabilities": [
{
"capability-type": "FCI.Metadata",
"capability-value": {
"metadata": []
},
"footprints": [
<Footprint objects>
]
}
]
}
4. CDNI FCI Capabilities Filtering Service
4.1. Filtered CDNI FCI Map
4.1.1. Media Type
Since a Filtered CDNI FCI Map is still a CDNI FCI Map, it uses the
media type defined for CDNI FCI Map (see Section 3.1.1).
4.1.2. HTTP Method
A Filtered CDNI FCI Map is requested using the HTTP POST method.
4.1.3. Accept Input Parameters
TBD.
4.1.4. Capabilities
None.
4.1.5. Uses
TBD.
Ma & Seedorf Expires October 24, 2016 [Page 15]
Internet-Draft CDNI FCI April 2016
4.1.6. Response
The format is the same as unfiltered CDNI FCI Map (see
Section 3.1.6).
4.1.7. Example
TBD.
5. Footprint via ALTO Network Map
5.1. ALTO Network Maps
The ALTO Protocol offers an information service "ALTO map service"
that provides information to ALTO clients in the form of Network Map
and Cost Map [RFC7285]. As an alternative to the explicit definition
of a CDNI Footprint Type (e.g., ipv4cidr, ipv6cidr, as, countrycode),
a reference to an ALTO network map can be used to define an FCI
footprint. To enable such referencing to ALTO network maps, a new
CDNI Footprint Type "altonetworkmap" is defined (see also
Section 6.2).
The first altonetworkmap entry must be a URI for accessing the ALTO
server that hosts the ALTO network map (as defined in the ALTO
protocol specification [RFC7285]). All subsequent altonetworkmap
entries must be of type PIDName (as defined in [RFC7285], where the
PIDName corresponds to a PID in the ALTO network map referenced by
the preceding URI. Parsing and processing of an ALTO network map
follows the ALTO protocol specification [RFC7285].
5.2. Example ALTO Network Map for CDNI FCI Footprint
An ALTO client can retrieve a network map of media type 'application/
alto-networkmap+json' under a given URI (e.g.,
'http://alto.example.com/fcifootprint001') with a GET request for a
network map as specified in the ALTO protocol [RFC7285]. The
following network map would convey to a uCDN that the given dCDN
(which would provide the map) has three footprints called "south-
france" and "germany", and provides the corresponding IPv4 address
ranges for these footprints.
Ma & Seedorf Expires October 24, 2016 [Page 16]
Internet-Draft CDNI FCI April 2016
GET /networkmap HTTP/1.1
Host: http://alto.example.com/fcifootprint001
Accept: application/alto-networkmap+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: 319
Content-Type: application/alto-networkmap+json
{
"meta" : {
"vtag": [
{"resource-id": "my-eu-netmap",
"tag": "1266506139"
}
]
},
"network-map" : {
"south-france" : {
"ipv4" : [ "192.0.2.0/24", "198.51.100.0/25" ]
},
"germany" : {
"ipv4" : [ "192.0.3.0/24"]
}
}
}
5.3. Example of ALTO Network Map Footprint in FCI Map
To reference an ALTO network map as an FCI footprint, set the
footprint-type to "altonetworkmap", and set the first entry in the
footprint-value to the URI of the ALTO server hosting the network
map, followed by a list of PID names contained in the network map.
The following example shows two lists of delivery protocols (see
Section 3.1.7.1), with the second having an ALTO network map
footprint.
Ma & Seedorf Expires October 24, 2016 [Page 17]
Internet-Draft CDNI FCI April 2016
GET /fcimap HTTP/1.1
Host: alto.example.com
Accept: application/alto-fcimap+json,application/alto-error+json
HTTP/1.1 200 OK
Content-Length: 618
Content-Type: application/alto-fcimap+json
{
"meta" : {
},
"fcimap": {
"capabilities": [
{ "capability-type": "FCI.DeliveryProtocol",
"capability-value": [
"http1.1"
]
},
{ "capability-type": "FCI.DeliveryProtocol",
"capability-value": [
"values": [
"https1.1"
],
"footprints": [
{ "footprint-type": "altonetworkmap",
"footprint-value": [
"http://alto.example.com/fcifootprint001",
"germany",
"south-france"
]
}
]
}
]
}
}
In the above example, the HTTP/1.1 protocol is supported globally,
while the HTTP/1.1 over TLS protocol is only supported in a
restricted footprint (in this case, specified by an ALTO network map
for Germany and Southern France).
6. IANA Considerations
Ma & Seedorf Expires October 24, 2016 [Page 18]
Internet-Draft CDNI FCI April 2016
6.1. ALTO Media Types
This document requests the registration of the following media types:
+-------------+-----------------------------+
| Type | Subtype |
+-------------+-----------------------------+
| application | alto-cdni-fcimap+json |
| application | alto-cdni-fcimapfilter+json |
+-------------+-----------------------------+
6.1.1. ALTO CDNI FCI Map Media Type
Type name: application
Subtype name: alto-cdni-fcimap+json
Required parameters: none
Optional parameters: none
Encoding considerations:
Encoding considerations are identical to those specified for the
"application/json" media type. See [RFC7159].
Security considerations:
Security considerations relating to the generation and consumption
of ALTO Protocol messages are discussed in Section 15 of
[RFC7285]. Additional security considerations for the CDNI
Footprint & Capabilities Advertisement interface are discussed in
Section 7.
Interoperability considerations:
[RFC7285] and RFCthis specify the format of conforming messages
and the interpretation thereof. [RFC Editor: Please replace
RFCthis with the published RFC number for this document.]
Published specification: RFCthis [RFC Editor: Please replace RFCthis
with the published RFC number for this document.]
Applications that use this media type:
ALTO servers and ALTO clients either stand alone or are embedded
within other applications.
Ma & Seedorf Expires October 24, 2016 [Page 19]
Internet-Draft CDNI FCI April 2016
Fragment identifier considerations: N/A
Additional information: N/A
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): N/A
Macintosh file type code(s): N/A
Person & email address to contact for further information:
Kevin Ma <kevin.j.ma@ericsson.com>
Intended usage: LIMITED USE
Restrictions on usage:
This media type is intended only for use in CDNI Footprint &
Capabilities Advertisement interface protocol message exchanges.
Author: IETF CDNI working group
Change controller: IETF CDNI working group
Provisional registration: no
6.1.2. ALTO CDNI FCI Map Filter Media Type
Type name: application
Subtype name: alto-cdni-fcimapfilter+json
Required parameters: none
Optional parameters: none
Encoding considerations:
Encoding considerations are identical to those specified for the
"application/json" media type. See [RFC7159].
Security considerations:
Security considerations relating to the generation and consumption
of ALTO Protocol messages are discussed in Section 15 of
Ma & Seedorf Expires October 24, 2016 [Page 20]
Internet-Draft CDNI FCI April 2016
[RFC7285]. Additional security considerations for the CDNI
Footprint & Capabilities Advertisement interface are discussed in
Section 7.
Interoperability considerations:
[RFC7285] and RFCthis specify the format of conforming messages
and the interpretation thereof. [RFC Editor: Please replace
RFCthis with the published RFC number for this document.]
Published specification: RFCthis [RFC Editor: Please replace RFCthis
with the published RFC number for this document.]
Applications that use this media type:
ALTO servers and ALTO clients either stand alone or are embedded
within other applications.
Fragment identifier considerations: N/A
Additional information: N/A
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): N/A
Macintosh file type code(s): N/A
Person & email address to contact for further information:
Kevin Ma <kevin.j.ma@ericsson.com>
Intended usage: LIMITED USE
Restrictions on usage:
This media type is intended only for use in CDNI Footprint &
Capabilities Advertisement interface protocol message exchanges.
Author: IETF CDNI working group
Change controller: IETF CDNI working group
Provisional registration: no
Ma & Seedorf Expires October 24, 2016 [Page 21]
Internet-Draft CDNI FCI April 2016
6.2. CDNI Footprint Types
This document requests the following addition to the "CDNI Metadata
Footprint Types" registry:
+----------------+----------------------------------+---------------+
| Footprint Type | Description | Specification |
+----------------+----------------------------------+---------------+
| altonetworkmap | URI of an ALTO Server hosting an | RFCthis |
| | ALTO network map, followed by a | |
| | list of PID-names | |
+----------------+----------------------------------+---------------+
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
7. Security Considerations
There are a number of security concerns associated with the FCI. The
FCI essentially provides configuration information which the uCDN
uses to make request routing decisions. Injection of fake capability
advertisement messages or the interception and discard of real
capability advertisement messages may be used for denial of service
(e.g., by falsely advertising or deleting capabilities or preventing
capability advertisements from reaching the uCDN). FCI messages may
also be monitored to detect when CDN performance degrades or outages
occur. Such information may be considered private by the dCDN.
dCDN capability advertisements MUST be authenticated by the uCDN to
prevent unauthorized capability injection. uCDN FCI servers MUST be
authenticated by the dCDN to prevent unauthorized interception of
ALTO messages. Encryption MUST be used to ensure confidentiality of
the dCDN's private messages.
7.1. Securing the CDNI Footprint & Capabilities Advertisement interface
An implementation of the CDNI Footprint & Capabilities Advertisement
interface MUST support TLS transport as per [RFC2818] and [RFC7230].
The use of TLS for transport of the CDNI metadata interface messages
allows:
o The dCDN and uCDN to authenticate each other.
and, once they have mutually authenticated each other, it allows:
o The dCDN and uCDN to authorize each other (to ensure they are
transmitting/receiving CDNI FCI messages from an authorized CDN);
Ma & Seedorf Expires October 24, 2016 [Page 22]
Internet-Draft CDNI FCI April 2016
o CDNI FCI messages to be transmitted with confidentiality; and
o The integrity of the CDNI FCI messages to be protected during the
exchange.
In an environment where any such protection is required, TLS MUST be
used (including authentication of the remote end) by the server-side
(uCDN) and the client-side (dCDN) of the CDNI Footprint &
Capabilities Advertisement interface unless alternate methods are
used for ensuring the confidentiality of the information in the CDNI
FCI messages (such as setting up an IPsec tunnel between the two CDNs
or using a physically secured internal network between two CDNs that
are owned by the same corporate entity).
When TLS is used, the general TLS usage guidance in [RFC7525] MUST be
followed.
8. Acknowledgements
The authors would like to thank Jon Peterson, Ray van Brandenburg,
Gilles Bertrand, and Scott Wainner 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.
9. References
9.1. Normative References
[I-D.ietf-cdni-footprint-capabilities-semantics]
Seedorf, J., Peterson, J., Previdi, S., Brandenburg, R.,
and K. Ma, "CDNI Request Routing: Footprint and
Capabilities Semantics", draft-ietf-cdni-footprint-
capabilities-semantics-16 (work in progress), April 2016.
[I-D.ietf-cdni-logging]
Faucheur, F., Bertrand, G., Oprescu, I., and R.
Peterkofsky, "CDNI Logging Interface", draft-ietf-cdni-
logging-25 (work in progress), April 2016.
Ma & Seedorf Expires October 24, 2016 [Page 23]
Internet-Draft CDNI FCI April 2016
[I-D.ietf-cdni-metadata]
Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
"CDN Interconnection Metadata", draft-ietf-cdni-
metadata-15 (work in progress), April 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<http://www.rfc-editor.org/info/rfc7230>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
"Application-Layer Traffic Optimization (ALTO) Protocol",
RFC 7285, DOI 10.17487/RFC7285, September 2014,
<http://www.rfc-editor.org/info/rfc7285>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <http://www.rfc-editor.org/info/rfc7525>.
9.2. Informative References
[I-D.ietf-cdni-redirection]
Niven-Jenkins, B. and R. Brandenburg, "Request Routing
Redirection interface for CDN Interconnection", draft-
ietf-cdni-redirection-18 (work in progress), April 2016.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000,
<http://www.rfc-editor.org/info/rfc2818>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <http://www.rfc-editor.org/info/rfc7159>.
Ma & Seedorf Expires October 24, 2016 [Page 24]
Internet-Draft CDNI FCI April 2016
[RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
August 2014, <http://www.rfc-editor.org/info/rfc7336>.
[RFC7337] Leung, K., Ed. and Y. Lee, Ed., "Content Distribution
Network Interconnection (CDNI) Requirements", RFC 7337,
DOI 10.17487/RFC7337, August 2014,
<http://www.rfc-editor.org/info/rfc7337>.
[RFC7736] Ma, K., "Content Delivery Network Interconnection (CDNI)
Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
December 2015, <http://www.rfc-editor.org/info/rfc7736>.
Appendix A. Capability Aggregation
The following sections show examples of three aggregation scenarios.
In each case, CDN-U is the ultimate uCDN and CDN-P is the penultimate
CDN which must perform capabilities aggregation.
A.1. Downstream CDN Aggregation
Figure A1 shows five organizationally different CDNs: CDN-U, CDN-P,
and CDNS A, B, and C, the dCDNs of CDN-P which are being aggregated.
Given the setup shown in Figure A1, we can construct a number of use
cases, based on the coverage areas of each dCDN (i.e., CDNs P, A, B,
and C). Note: In all cases, the reachability of the uCDN (i.e., CDN-
U) is a don't care as it is assumed that the uCDN knows its own
coverage area and is likely to favor itself in most situations, and
if it has decided that it needs to delegate to a dCDN, then the only
relevant question is if the dCDN can handle the request.
Ma & Seedorf Expires October 24, 2016 [Page 25]
Internet-Draft CDNI FCI April 2016
,---,---,---.
,-' `-.
( rr0.u.example.com )
`-. CDN-U ,-'
`---'-+-'- --'
|
,---,-+-,---.
,-' `-.
( rr0.p.example.com )
`-. CDN-P ,-'
`---'-+-'---'
|
+---------------------+---------------------+
/ | \
,---,-+-,---. ,---,-+-,---. ,---,-+-,---.
,-' `-. ,-' `-. ,-' `-.
( rr0.a.example.com ) ( rr0.b.example.com ) ( rr0.c.example.com )
`-. CDN-A ,-' `-. CDN-B ,-' `-. CDN-C ,-'
`---'---'---' `---'---'---' `---'---'---'
Figure A1: CDNI dCDN Request Router Aggregation
o None of the four dCDNs (CDNs P, A, B, and C) have global
reachability. In this case, each CDN is likely to advertise
footprint information with its capabilities, specifying its
reachability. When CDN-P advertises capabilities to CDN-U, it may
advertise the aggregate footprint of itself and CDNs A, B, and C.
Note: CDN-P MAY exclude any dCDN, and consequently its footprint,
per its own internal aggregation decision criteria.
o All four dCDNs (CDNs P, A, B, and C) have global reachability. In
this case, none of the CDNs is likely to advertise any footprint
information as none have any footprint restrictions. When CDN-P
advertises capabilities to CDN-U, the aggregate of all global
reachability is global reachability.
o Some of the four dCDNs (CDNs P, A, B, and C) have global
reachability and some do not. In this case, even though some
dCDNs do not have global reachability, the aggregate of some dCDNs
having global reachability and some not should still be global
reachability (for the given capability). When CDN-P advertises
capabilities to CDN-U, CDN-P may advertise capabilities for which
at least one dCDN has global reach as being supported with global
reachability. It is up to the CDN-P request router to properly
select a dCDN to process individual client requests and not choose
a dCDN whose restricted footprint makes it unsuitable for
delivering the requested content.
Ma & Seedorf Expires October 24, 2016 [Page 26]
Internet-Draft CDNI FCI April 2016
A.2. Internal Request Router Aggregation
Figure A2 shows CDN-U and CDN-P where CDN-P internally has four
request routers: the authoritative request router rr0, and three
other request routers rr1, rr2, and rr3. The use of multiple request
routers may be used to distribute request routing load across
resources, possibly in different geographic regions covered by CDN-P.
Similar to Figure A1, the setup shown in Figure A2 requires the
authoritative request router rr0 in CDN-P to aggregate capabilities
information from downstream request routers rr1, rr2, and rr3. The
primary difference between the scenario is that the request routers
in Figure A2 are logically within the same CDN-P organization. The
same reachability scenarios apply to Figure A2 as with Figure A1.
,---,---,---.
,-' `-.
( rr0.u.example.com )
`-. CDN-U ,-'
`---'-+-'---'
|
,---,---,---,--,-+-,--,---,---,---.
( )
,-' +-------------------+ `-.
( | rr0.p.example.com | )
,-' +---------+---------+ `-.
( | )
,-' +----------+----------+ `-.
( / | \ )
) +---------+---------+ | +---------+---------+ (
( | rr1.p.example.com | | | rr3.p.example.com | )
`. +-------------------+ | +-------------------+ ,'
( | )
`-. +---------+---------+ ,-'
( | rr2.p.example.com | )
`-. +-------------------+ ,-'
( CDN-P )
`---'---'---'---'---'---'---'---'---'
Figure A2: Local CDN Request Router Aggregation
o None of the four CDN-P request routers have global reachability.
In this case, each request router is likely to advertise footprint
information with its capabilities, specifying its reachability.
When rr0 advertises capabilities to CDN-U, it may advertise the
aggregate footprint of itself and rr1, rr2, and rr3.
o All four CDN-P request routers have global reachability. In this
case, none of the request routers is likely to advertise any
Ma & Seedorf Expires October 24, 2016 [Page 27]
Internet-Draft CDNI FCI April 2016
footprint information as none has any footprint restrictions.
When rr0 advertises capabilities to CDN-U, the aggregate of all
global reachability is global reachability.
o Some of the four CDN-P request routers have global reachability
and some do not. In this case, even though some request routers
do not have global reachability, the aggregate of some request
routers having global reachability and some not should still be
global reachability (for the given capability). When rr0
advertises capabilities to CDN-U, CDN-P may advertise capabilities
for which at least one request router has global reach as being
supported with global reachability. It is up to the authoritative
request router rr0 to properly select from the other request
routers for any given request, and not choose a request router
whose restricted footprint makes it unsuitable for delivering the
requested content.
A.3. Internal Capability Aggregation
Figure A3 shows CDN-U and CDN-P where the delivery network of CDN-P
is segregated by delivery protocol (e.g., RTSP, HTTP, and RTMP).
Figure A3 differs from Figures A1 and A2 in that request router rr0
of CDN-P is not aggregating the capabilities advertisements of
multiple other downstream request routers, but rather it is managing
the disparate capabilities across resources within its own local CDN.
Though not every delivery node has the same protocol capabilities,
the aggregate delivery protocol capabilities advertised by CDN-A may
include all delivery protocols. Note, Figure A3 should not be
construed to imply anything about the coverage areas for each
delivery protocol. They may all support the same delivery footprint,
or they may have different delivery footprints. It is the
responsibility of the request router rr0 to properly assign protocol-
appropriate delivery nodes to individual content requests. If
certain protocols have limited reachability, CDN-P may advertise
footprint restrictions for each protocol.
It should be noted that though the delivery protocol capability was
selected for this example, the concept of internal capability
aggregation applies to all capabilities as discussed below.
Ma & Seedorf Expires October 24, 2016 [Page 28]
Internet-Draft CDNI FCI April 2016
,---,---,---.
,-' `-.
( rr0.u.example.com )
`-. CDN-U ,-'
`---'-+-'---'
|
,---,---,---,--,-+-,--,---,---,---.
( )
,-' +-------------------+ `-.
( | rr0.p.example.com | )
,-' +---------+---------+ `-.
( . )
,-' ....................... `-.
( . . . )
) +-------------------+ . +-------------------+ (
( |rtsp.p.example.com | . |rtmp.p.example.com | )
`. +-------------------+ . +-------------------+ ,'
( . )
`-. +-------------------+ ,-'
( |http.p.example.com | )
`-. +-------------------+ ,-'
( CDN-A )
`---'---'---'---'---'---'---'---'---'
Figure A3: Local CDN Capability Segregation
Another situation in which physical footprint may not matter in an
aggregated view has to do with feature support (e.g., new CDNI
metadata features or new redirection modes). Situations often arise
when phased roll-out of software upgrades, or staging network
segregation result in only certain portions of a CDN's resources
supporting the new feature set. The dCDN has a few options in this
case:
o Enforce atomic update: The dCDN does not advertise support for the
new capability until all resources have been upgraded to support
the new capability.
o Transparent segregation: The dCDN advertises support for the new
capability, and when requests are received that require the new
capability, the dCDN request router properly selects a resource
which supports that capability.
o Advertised segregation: The dCDN advertises support for the new
capability with a footprint restriction allowing the uCDN to make
delegation decisions based on the dCDN's limit support.
Ma & Seedorf Expires October 24, 2016 [Page 29]
Internet-Draft CDNI FCI April 2016
The level of aggregation employed by the dCDN is likely to vary as
business relationships dictate, however, the FCI should support all
possible modes of operation.
Authors' Addresses
Kevin J. Ma
Ericsson
43 Nagog Park
Acton, MA 01720
USA
Phone: +1 978-844-5100
Email: kevin.j.ma@ericsson.com
Jan Seedorf
NEC
Kurfuerstenanlage 36
Heidelberg 69115
Germany
Phone: +49 6221 4342 221
Fax: +49 6221 4342 155
Email: seedorf@neclab.eu
Ma & Seedorf Expires October 24, 2016 [Page 30]
