Content Distribution Network Interconnection (CDNI) Footprint & Capabilities Advertisement Interface
draft-ma-cdni-capabilities-02
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draft-ma-cdni-capabilities-02
Network Working Group K. Ma
Internet-Draft Azuki Systems, Inc.
Intended status: Standards Track August 04, 2013
Expires: February 05, 2014
Content Distribution Network Interconnection (CDNI) Footprint &
Capabilities Advertisement Interface
draft-ma-cdni-capabilities-02
Abstract
The interconnection of Content Distribution Networks (CDNs) 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 February 05, 2014.
Copyright Notice
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Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Capabilities . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Delivery Protocol . . . . . . . . . . . . . . . . . . . . 6
2.2. Acquisition Protocol . . . . . . . . . . . . . . . . . . 7
2.3. Redirection Mode . . . . . . . . . . . . . . . . . . . . 8
3. Capability Advertisement . . . . . . . . . . . . . . . . . . 10
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Capability Aggregation . . . . . . . . . . . . . . . 11
A.1. Downstream CDN Aggregation . . . . . . . . . . . . . . . 11
A.2. Internal Request Router Aggregation . . . . . . . . . . . 13
A.3. Internal Capability Aggregation . . . . . . . . . . . . . 14
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
The need for footprint and capabilities advertisement in CDNI is
described in the CDNI requirements document
[I-D.ietf-cdni-requirements]. 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,
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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 receiving and aggregating capabilities
information in the uCDN. The CDNI Footprint & Capabilities
Advertisement interface (FCI) along with the CDNI Request Routing
Redirection interface (RI) 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. 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.
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1.1. Terminology
This document uses the terminology defined in section 1.1 of the CDNI
Framework [I-D.ietf-cdni-framework] document.
2. Capabilities
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. The CDNI Footprint and Capabilities Semantics
[I-D.ietf-cdni-footprint-capabilities-semantics] document lists
mandatory capabilities types:
o Delivery Protocol
o Acquisition Protocol
o Redirection Mode
o CDNI Logging Capabilities
o CDNI Metadata Capabilities
The following sections describe each of the capabilities in further
detail, however, all of the capabilities can be described using the
same general format. A capability object is specified as:
CapabilityObject:
Name: Identifier for the capability
Values: List of supported options for the capability
Footprint: Optional list of footprint objects
The list of valid capability options for a given capability will be
specific to the given capability type. Though the degenerate case
may exist where the range of option values is a single value, it is
anticipated that all capability types will have more than one
capability option value. For consistency in the model, all
capability types are implemented with lists of values. To optimize
actions on the entire range of capability option values for a given
capability type, the capability option value "ALL" is reserved and
MUST be supported by all capability types. For completeness, the
capability option value "NONE" is also reserved and MUST be supported
by all capability types. If a reserved value is specified, it MUST
be the only entry in the capability value list.
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The footprint restriction list is optional. When included, the
footprint restriction list contains a list of generic footprint
objects. The footprint object is specified as:
FootprintObject:
Type: Identifier for the capability
Values: List of footprint entries
Mode: Optional footprint application directive
The footprint type specifies the format of the footprint value
entries. The footprint object type field contains the IANA registry
defined footprint type name. The CDNI Footprint and Capabilities
Semantics [I-D.ietf-cdni-footprint-capabilities-semantics] document
lists the mandatory footprint types as: ISO Country Code, AS number,
and IP-prefix. The CDNI Footprint and Capabilities Semantics
[I-D.ietf-cdni-footprint-capabilities-semantics] document defines the
footprint type names for the mandatory footprint types and describes
the process for defining additional optional footprint types. The
footprint value "GLOBAL" is reserved and MUST be supported by all
footprint types. If the reserved value "GLOBAL" is specified, it
MUST be the only entry in the footprint value list.
The optional footprint mode describes how the footprint should be
applied. The valid footprint mode values are: "replace", "include",
and "exclude". The footprint mode "replace" (represented by the
integer value 0) indicates that all previous footprint information
for the given footprint type (and for the capabilities to which the
current footprint object applies) MUST be replaced in its entirety
with the footprint information specified in the accompanying
footprint value list. The footprint mode "include" (represented by
the integer value 1) indicates that the any existing footprint
information for the given footprint type (and for the capabilities to
which the current footprint object applies) SHOULD be augmented with
the footprint information specified in the accompanying footprint
value list. The footprint mode "exclude" (represented by the integer
value 2) indicates that the any existing footprint information for
the given footprint type (and for the capabilities to which the
current footprint object applies) SHOULD be reduced by the footprint
information specified in the accompanying footprint value list. If
no footprint mode value is specified, the default mode SHALL be
understood to be "replace".
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The footprint restriction list MUST NOT contain multiple footprint
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 critical to 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 capability objects of the same capability type are allowed
within a given FCI message as long as the capability option values do
not overlap, i.e., a given capability option value MUST NOT show up
in multiple capability objects within a single FCI message. If
multiple capability objects for a given capability type exist, those
capability objects SHOULD have different footprint restrictions;
capability objects of a given capability type with identical
footprint restrictions SHOULD be combined into a single capability
object.
2.1. 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 [RFC3986]) of the client request URL, protocol
feature subsets or augmented protocol feature sets MAY be defined and
SHOULD correspond with the protocols supported by the ProtocolACL
defined in the CDNI Metadata Interface [I-D.ietf-cdni-metadata]
document.
The delivery protocol capability object MUST support a list of
protocols for a given footprint. The delivery protocol capability
SHOULD support optional footprint restriction information. The
following example shows two lists of protocols with different
footprints.
{
"capabilities": [
{ "name": "delivery_protocol",
"values": [
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"HTTP",
"RTSP",
"MMS"
]
},
{ "name": "delivery_protocol",
"values": [
"RTMP",
"HTTPS"
],
"footprint": [
{ "type": "IPv4",
"values": [
"10.1.0.0/16",
"10.10.10.0/24"
]
}
]
}
]
}
In the above example, the three protocols HTTP, RTSP, and MMS are
supported globally, while the protocols RTMP and HTTPS are only
supported in a restricted footprint (in this case, specified by IP-
prefix).
A given protocol MUST NOT appear in multiple capability object value
lists, within a given FCI message.
2.2. Acquisition Protocol
The acquisition protocol refers to the protocol over which the dCDN
may acquire content from the uCDN. If a dCDN does not support any of
the protocols offered by the uCDN, then the dCDN is not a viable
candidate for delegation.
Though the acquisition protocol is disseminated to the dCDN in the
URI scheme (as defined in RFC3986 [RFC3986]) of the URL provided by
the uCDN via the CDNI Metadata Interface [I-D.ietf-cdni-metadata],
protocol feature subsets or augmented protocol feature sets MAY be
defined and SHOULD correspond with the protocols supported by the
ProtocolACL defined in the CDNI Metadata Interface
[I-D.ietf-cdni-metadata] document.
The acquisition protocol capability object MUST support a list of
protocols for a given footprint. The acquisition protocol capability
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SHOULD support optional footprint restriction information. The
following example shows two lists of protocols with different
footprints.
{
"capabilities": [
{ "name": "acquisition_protocol",
"values": [
"HTTP",
"FTP"
]
},
{ "name": "acquisition_protocol",
"values": [
"SFTP",
"HTTPS"
],
"footprint": [
{ "type": "ASN",
"values": [
"0",
"65535"
],
"mode": 2
}
]
}
]
}
In the above example, the two protocols HTTP and FTP are supported
globally, while the protocols SFTP and HTTPS are updated to only be
supported in a reduced restricted footprint (in this case, specified
by ASN).
A given protocol MUST NOT appear in multiple capability object value
lists, within a given FCI message.
2.3. Redirection Mode
The redirection mode refers to the method(s) employed by request
routers to perform request redirection. The CDNI framework
[I-D.ietf-cdni-framework] document describes four possible request
routing modes:
o DNS iterative (DNS-I)
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o DNS recursive (DNS-R)
o HTTP iterative (HTTP-I)
o HTTP recursive (HTTP-R)
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 is
not a viable candidate for delegation.
The redirection mode capability object MUST support a list of
redirection modes for a given footprint. The redirection mode
capability SHOULD support optional footprint restriction information.
The following XML-encoded example shows two lists of modes with
different footprints.
{
"capabilities": [
{ "name": "redirection_mode",
"values": [
"DNS-I",
"HTTP-I"
]
},
{ "name": "redirection_mode",
"values": [
"DNS-R",
"HTTP-R"
],
"footprint": [
{ "type": "ASN",
"values": [
"9"
],
"mode": 0
},
{ "type": "IPv6",
"values": [
"8765:4321::/36"
]
}
]
}
]
}
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In the above example, iterative redirection is supported globally,
while recursive redirection is only supported in a restricted
footprint (in this case, specified by both ASN and IP-prefix).
A given mode MUST NOT appear in multiple capability object value
lists, within a given FCI message.
3. Capability Advertisement
The FCI relies an HTTP-based protocol using the POST method. The
dCDN request router asynchronously issues FCI messages to the uCDN
request router (see Appendix A for detailed descriptions of
authoritative request router capabilities aggregation scenarios). It
is assumed that the dCDN request router has been configured with the
uCDN request router address either through the CDNI Control interface
bootstrapping function, or through some other out-of-band
configuration.
4. IANA Considerations
This memo includes no request to IANA.
5. 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). dCDN capability
advertisements MUST be authenticated by the uCDN to prevent
unauthorized FCI message injection. uCDN FCI servers MUST be
authenticated by the dCDN to prevent unauthorized interception of FCI
messages. TLS with client authentication SHOULD be used for all FCI
implementations. Deployments in controlled environments where
physical security and IP address white-listing is employed MAY choose
not to use TLS.
6. Acknowledgements
The authors would like to thank Ray van Brandenburg, Gilles Bertrand,
and Scott Wainner for their timely reviews and invaluable comments.
7. References
7.1. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005.
7.2. Informative References
[I-D.ietf-cdni-footprint-capabilities-semantics]
Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
R., and K. Ma, "CDNI Request Routing: Footprint and
Capabilities Semantics draft-ietf-cdni-footprint-
capabilities-semantics-00", July 2013.
[I-D.ietf-cdni-framework]
Peterson, L., Ed. and B. Davie, Ed., "Framework for CDN
Interconnection draft-ietf-cdni-framework-03", February
2013.
[I-D.ietf-cdni-logging]
Le Faucheur, F., Bertrand, G., Oprescu, I., and R.
Peterkofsky, "CDNI Logging Interface draft-ietf-cdni-
logging-05", July 2013.
[I-D.ietf-cdni-metadata]
Niven-Jenkins, B., Murray, R., Watson, G., Caulfield, M.,
Leung, K., and K. Ma, "CDN Interconnect Metadata draft-
ietf-cdni-metadata-02", July 2013.
[I-D.ietf-cdni-requirements]
Leung, K. and Y. Lee, "Content Distribution Network
Interconnection (CDNI) Requirements draft-ietf-cdni-
requirements-09", July 2013.
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.,
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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.
,---,---,---.
,-' `-.
( 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
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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.
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.
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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
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.
,---,---,---.
,-' `-.
( rr0.u.example.com )
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`-. 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.
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.
Ma Expires February 05, 2014 [Page 15]
Internet-Draft CDNI Metadata August 2013
Author's Address
Kevin J. Ma
Azuki Systems, Inc.
43 Nagog Park
Acton, MA 01720
USA
Phone: +1 978-844-5100
Email: kevin.ma@azukisystems.com
Ma Expires February 05, 2014 [Page 16]