draft-ietf-cdni-problem-statement-05.txt   draft-ietf-cdni-problem-statement-06.txt 
Network Working Group B. Niven-Jenkins Network Working Group B. Niven-Jenkins
Internet-Draft Velocix (Alcatel-Lucent) Internet-Draft Velocix (Alcatel-Lucent)
Intended status: Informational F. Le Faucheur Intended status: Informational F. Le Faucheur
Expires: November 4, 2012 Cisco Expires: November 21, 2012 Cisco
N. Bitar N. Bitar
Verizon Verizon
May 3, 2012 May 20, 2012
Content Distribution Network Interconnection (CDNI) Problem Statement Content Distribution Network Interconnection (CDNI) Problem Statement
draft-ietf-cdni-problem-statement-05 draft-ietf-cdni-problem-statement-06
Abstract Abstract
Content Delivery Networks (CDNs) provide numerous benefits: reduced Content Delivery Networks (CDNs) provide numerous benefits: reduced
delivery cost for cacheable content, improved quality of experience delivery cost for cacheable content, improved quality of experience
for End Users and increased robustness of delivery. For these for End Users and increased robustness of delivery. For these
reasons they are frequently used for large-scale content delivery. reasons they are frequently used for large-scale content delivery.
As a result, existing CDN Providers are scaling up their As a result, existing CDN Providers are scaling up their
infrastructure and many Network Service Providers (NSPs) are infrastructure and many Network Service Providers (NSPs) are
deploying their own CDNs. It is generally desirable that a given deploying their own CDNs. It is generally desirable that a given
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 4, 2012. This Internet-Draft will expire on November 21, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
1.2. CDN Background . . . . . . . . . . . . . . . . . . . . . . 10 1.2. CDN Background . . . . . . . . . . . . . . . . . . . . . . 10
2. CDN Interconnection Use Cases . . . . . . . . . . . . . . . . 10 2. CDN Interconnection Use Cases . . . . . . . . . . . . . . . . 10
3. CDN Interconnection Model & Problem Area for IETF . . . . . . 11 3. CDN Interconnection Model & Problem Area for IETF . . . . . . 12
4. Scoping the CDNI Problem . . . . . . . . . . . . . . . . . . . 15 4. Scoping the CDNI Problem . . . . . . . . . . . . . . . . . . . 16
4.1. CDNI Request Routing Interface . . . . . . . . . . . . . . 16 4.1. CDNI Request Routing Interface . . . . . . . . . . . . . . 17
4.2. CDNI Metadata Interface . . . . . . . . . . . . . . . . . 16 4.2. CDNI Metadata Interface . . . . . . . . . . . . . . . . . 17
4.3. CDNI Logging Interface . . . . . . . . . . . . . . . . . . 17 4.3. CDNI Logging Interface . . . . . . . . . . . . . . . . . . 18
4.4. CDNI Control Interface . . . . . . . . . . . . . . . . . . 17 4.4. CDNI Control Interface . . . . . . . . . . . . . . . . . . 18
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17 6. Security Considerations . . . . . . . . . . . . . . . . . . . 18
6.1. Security of the CDNI Control interface . . . . . . . . . . 18 6.1. Security of the CDNI Control interface . . . . . . . . . . 19
6.2. Security of the CDNI Request Routing Interface . . . . . . 18 6.2. Security of the CDNI Request Routing Interface . . . . . . 19
6.3. Security of the CDNI Metadata interface . . . . . . . . . 18 6.3. Security of the CDNI Metadata interface . . . . . . . . . 19
6.4. Security of the CDNI Logging interface . . . . . . . . . . 19 6.4. Security of the CDNI Logging interface . . . . . . . . . . 20
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.1. Normative References . . . . . . . . . . . . . . . . . . . 19 8.1. Normative References . . . . . . . . . . . . . . . . . . . 20
8.2. Informative References . . . . . . . . . . . . . . . . . . 19 8.2. Informative References . . . . . . . . . . . . . . . . . . 20
Appendix A. Design considerations for realizing the CDNI Appendix A. Design considerations for realizing the CDNI
Interfaces . . . . . . . . . . . . . . . . . . . . . 22 Interfaces . . . . . . . . . . . . . . . . . . . . . 23
A.1. CDNI Request Routing Interface . . . . . . . . . . . . . . 22 A.1. CDNI Request Routing Interface . . . . . . . . . . . . . . 23
A.2. CDNI Metadata Interface . . . . . . . . . . . . . . . . . 24 A.2. CDNI Metadata Interface . . . . . . . . . . . . . . . . . 25
A.3. CDNI Logging Interface . . . . . . . . . . . . . . . . . . 25 A.3. CDNI Logging Interface . . . . . . . . . . . . . . . . . . 26
A.4. CDNI Control Interface . . . . . . . . . . . . . . . . . . 26 A.4. CDNI Control Interface . . . . . . . . . . . . . . . . . . 27
Appendix B. Additional Material . . . . . . . . . . . . . . . . . 26 Appendix B. Additional Material . . . . . . . . . . . . . . . . . 27
B.1. Non-Goals for IETF . . . . . . . . . . . . . . . . . . . . 26 B.1. Non-Goals for IETF . . . . . . . . . . . . . . . . . . . . 27
B.2. Related standardization activites . . . . . . . . . . . . 28 B.2. Related standardization activites . . . . . . . . . . . . 29
B.2.1. IETF CDI Working Group (Concluded) . . . . . . . . . . 29 B.2.1. IETF CDI Working Group (Concluded) . . . . . . . . . . 30
B.2.2. 3GPP . . . . . . . . . . . . . . . . . . . . . . . . . 29 B.2.2. 3GPP . . . . . . . . . . . . . . . . . . . . . . . . . 30
B.2.3. ISO MPEG . . . . . . . . . . . . . . . . . . . . . . . 30 B.2.3. ISO MPEG . . . . . . . . . . . . . . . . . . . . . . . 31
B.2.4. ATIS IIF . . . . . . . . . . . . . . . . . . . . . . . 31 B.2.4. ATIS IIF . . . . . . . . . . . . . . . . . . . . . . . 32
B.2.5. CableLabs . . . . . . . . . . . . . . . . . . . . . . 31 B.2.5. CableLabs . . . . . . . . . . . . . . . . . . . . . . 32
B.2.6. ETSI MCD . . . . . . . . . . . . . . . . . . . . . . . 31 B.2.6. ETSI MCD . . . . . . . . . . . . . . . . . . . . . . . 32
B.2.7. ETSI TISPAN . . . . . . . . . . . . . . . . . . . . . 31 B.2.7. ETSI TISPAN . . . . . . . . . . . . . . . . . . . . . 32
B.2.8. ITU-T . . . . . . . . . . . . . . . . . . . . . . . . 32 B.2.8. ITU-T . . . . . . . . . . . . . . . . . . . . . . . . 33
B.2.9. Open IPTV Forum (OIPF) . . . . . . . . . . . . . . . . 32 B.2.9. Open IPTV Forum (OIPF) . . . . . . . . . . . . . . . . 33
B.2.10. TV-Anytime Forum . . . . . . . . . . . . . . . . . . . 32 B.2.10. TV-Anytime Forum . . . . . . . . . . . . . . . . . . . 33
B.2.11. SNIA . . . . . . . . . . . . . . . . . . . . . . . . . 33 B.2.11. SNIA . . . . . . . . . . . . . . . . . . . . . . . . . 34
B.2.12. Summary of existing standardization work . . . . . . . 33 B.2.12. Summary of existing standardization work . . . . . . . 34
B.3. Related Research Projects . . . . . . . . . . . . . . . . 35 B.3. Related Research Projects . . . . . . . . . . . . . . . . 36
B.3.1. IRTF P2P Research Group . . . . . . . . . . . . . . . 35 B.3.1. IRTF P2P Research Group . . . . . . . . . . . . . . . 36
B.3.2. OCEAN . . . . . . . . . . . . . . . . . . . . . . . . 35 B.3.2. OCEAN . . . . . . . . . . . . . . . . . . . . . . . . 36
B.3.3. Eurescom P1955 . . . . . . . . . . . . . . . . . . . . 35 B.3.3. Eurescom P1955 . . . . . . . . . . . . . . . . . . . . 36
B.4. Relationship to relevant IETF Working Groups . . . . . . . 36 B.4. Relationship to relevant IETF Working Groups . . . . . . . 37
B.4.1. ALTO . . . . . . . . . . . . . . . . . . . . . . . . . 36 B.4.1. ALTO . . . . . . . . . . . . . . . . . . . . . . . . . 37
B.4.2. DECADE . . . . . . . . . . . . . . . . . . . . . . . . 36 B.4.2. DECADE . . . . . . . . . . . . . . . . . . . . . . . . 37
B.4.3. PPSP . . . . . . . . . . . . . . . . . . . . . . . . . 38 B.4.3. PPSP . . . . . . . . . . . . . . . . . . . . . . . . . 39
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 38 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 39
1. Introduction 1. Introduction
The volume of video and multimedia content delivered over the The volume of video and multimedia content delivered over the
Internet is rapidly increasing and expected to continue doing so in Internet is rapidly increasing and expected to continue doing so in
the future. In the face of this growth, Content Delivery Networks the future. In the face of this growth, Content Delivery Networks
(CDNs) provide numerous benefits: reduced delivery cost for cacheable (CDNs) provide numerous benefits: reduced delivery cost for cacheable
content, improved quality of experience for End Users (EUs) and content, improved quality of experience for End Users (EUs) and
increased robustness of delivery. For these reasons CDNs are increased robustness of delivery. For these reasons CDNs are
frequently used for large-scale content delivery. As a result, frequently used for large-scale content delivery. As a result,
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It is generally desirable that a given content item can be delivered It is generally desirable that a given content item can be delivered
to an EU regardless of that EU's location or the network they are to an EU regardless of that EU's location or the network they are
attached to. However, a given CDN in charge of delivering a given attached to. However, a given CDN in charge of delivering a given
content may not have a footprint that expands close enough to the content may not have a footprint that expands close enough to the
EU's current location or attachment network, or may not have the EU's current location or attachment network, or may not have the
necessary resources, to realize the user experience and cost benefit necessary resources, to realize the user experience and cost benefit
that a more distributed CDN infrastructure would allow. This is the that a more distributed CDN infrastructure would allow. This is the
motivation for interconnecting standalone CDNs so that their motivation for interconnecting standalone CDNs so that their
collective CDN footprint and resources can be leveraged for the end- collective CDN footprint and resources can be leveraged for the end-
to-end delivery of content from CSPs to EUs. As an example, a CSP to-end delivery of content from Content Service Providers (CSPs) to
could contract with an "authoritative" CDN Provider for the delivery EUs. As an example, a CSP could contract with an "authoritative" CDN
of content and that authoritative CDN Provider could contract with Provider for the delivery of content and that authoritative CDN
one or more downstream CDN Provider(s) to distribute and deliver some Provider could contract with one or more downstream CDN Provider(s)
or all of the content on behalf of the authoritative CDN Provider. to distribute and deliver some or all of the content on behalf of the
authoritative CDN Provider.
A typical end to end content delivery scenario would then involve the A typical end to end content delivery scenario would then involve the
following business arrangements: following business arrangements:
o A business arrangement between the EU and his CSP, authorizing o A business arrangement between the EU and his CSP, authorizing
access by the EU to content items controlled by the CSP. access by the EU to content items controlled by the CSP.
o A business arrangement between the CSP and an "authoritative" CDN o A business arrangement between the CSP and an "authoritative" CDN
Provider where the CSP authorizes the CDN Provider to perform the Provider where the CSP authorizes the CDN Provider to perform the
content delivery on behalf of the CSP. content delivery on behalf of the CSP.
o A business arrangement between the authoritative CDN Provider and o A business arrangement between the authoritative CDN Provider and
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acquires the content from content sources (including upstream CDNs) acquires the content from content sources (including upstream CDNs)
at some point in time after a request for that content is delegated at some point in time after a request for that content is delegated
to the downstream CDN by an Upstream CDN (and that specific content to the downstream CDN by an Upstream CDN (and that specific content
is not yet available in the downstream CDN). is not yet available in the downstream CDN).
Dynamic CDNI metadata acquisition: In the context of CDN Dynamic CDNI metadata acquisition: In the context of CDN
Interconnection, dynamic CDNI metadata acquisition means that a Interconnection, dynamic CDNI metadata acquisition means that a
downstream CDN acquires CDNI metadata for content from the upstream downstream CDN acquires CDNI metadata for content from the upstream
CDN at some point in time after a request for that content is CDN at some point in time after a request for that content is
delegated to the downstream CDN by an Upstream CDN (and that specific delegated to the downstream CDN by an Upstream CDN (and that specific
CDNI metadata is not yet available in the downstream CDN). CDNI metadata is not yet available in the downstream CDN). See also
the definitions for downstream CDN and upstream CDN.
Pre-positioned content acquisition: Content Pre-positioning is where Pre-positioned content acquisition: Content Pre-positioning is where
a CDN acquires content from the content source prior to, or a CDN acquires content from the content source prior to, or
independently of, any End User requesting that content from the CDN. independently of, any End User requesting that content from the CDN.
In the context of CDN interconnection the Upstream CDN instructs the In the context of CDN interconnection the Upstream CDN instructs the
Downstream CDN to acquire the content from content sources (including Downstream CDN to acquire the content from content sources (including
upstream CDNs) in advance of or independent of any End User upstream CDNs) in advance of or independent of any End User
requesting it. requesting it.
Pre-positioned CDNI Metadata acquisition: In the context of CDN Pre-positioned CDNI Metadata acquisition: In the context of CDN
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purging of content files and/or CDNI Metadata in a downstream purging of content files and/or CDNI Metadata in a downstream
CDN. CDN.
o CDNI Request Routing interface: This interface allows the Request o CDNI Request Routing interface: This interface allows the Request
Routing systems in interconnected CDNs to communicate to ensure Routing systems in interconnected CDNs to communicate to ensure
that an End User request can be (re)directed from an upstream CDN that an End User request can be (re)directed from an upstream CDN
to a surrogate in the downstream CDN, in particular where to a surrogate in the downstream CDN, in particular where
selection responsibilities may be split across CDNs (for example selection responsibilities may be split across CDNs (for example
the upstream CDN may be responsible for selecting the downstream the upstream CDN may be responsible for selecting the downstream
CDN while the downstream CDN may be responsible for selecting the CDN while the downstream CDN may be responsible for selecting the
actual surrogate within that downstream CDN). In particular, the actual surrogate within that downstream CDN). In particular, the
CDN Request Routing interface, may support the following: functions of the CDN Request Routing interface may be divided as
* Allow the upstream CDN to query the downstream CDN at request follows:
routing time before redirecting the request to the downstream * A CDNI Request Routing Redirection interface which allows the
CDN. upstream CDN to query the downstream CDN at request routing
* Allow the downstream CDN to provide to the upstream CDN (static time before redirecting the request to the downstream CDN.
or dynamic) information (e.g. resources, footprint, load) to * A CDNI Footprint & Capabilities advertisement interface which
facilitate selection of the downstream CDN by the upstream CDN allows the downstream CDN to provide to the upstream CDN
request routing system when processing subsequent content (static or dynamic) information (e.g. resources, footprint,
requests from User Agents. load) to facilitate selection of the downstream CDN by the
upstream CDN request routing system when processing subsequent
content requests from User Agents.
o CDNI Metadata distribution interface: This interface allows the o CDNI Metadata distribution interface: This interface allows the
Distribution system in interconnected CDNs to communicate to Distribution system in interconnected CDNs to communicate to
ensure CDNI Metadata can be exchanged across CDNs. See ensure CDNI Metadata can be exchanged across CDNs. See
Section 1.1 for definition and examples of CDNI Metadata. Section 1.1 for definition and examples of CDNI Metadata.
o CDNI Logging interface: This interface allows the Logging system o CDNI Logging interface: This interface allows the Logging system
in interconnected CDNs to communicate the relevant activity logs in interconnected CDNs to communicate the relevant activity logs
in order to allow log consuming applications to operate in a in order to allow log consuming applications to operate in a
multi-CDN environments. For example, an upstream CDN may collect multi-CDN environments. For example, an upstream CDN may collect
delivery logs from a downstream CDN in order to perform delivery logs from a downstream CDN in order to perform
consolidated charging of the CSP or for settlement purposes across consolidated charging of the CSP or for settlement purposes across
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unnecessary and it is recommended that existing application protocols unnecessary and it is recommended that existing application protocols
be reused or leveraged (HTTP [RFC2616], Atom Publishing Protocol be reused or leveraged (HTTP [RFC2616], Atom Publishing Protocol
[RFC5023], XMPP [RFC6120], for example) to realize the CDNI [RFC5023], XMPP [RFC6120], for example) to realize the CDNI
interfaces. interfaces.
4.1. CDNI Request Routing Interface 4.1. CDNI Request Routing Interface
The CDNI Request Routing interface enables a Request Routing function The CDNI Request Routing interface enables a Request Routing function
in an upstream CDN to query a Request Routing function in a in an upstream CDN to query a Request Routing function in a
downstream CDN to determine if the downstream CDN is able (and downstream CDN to determine if the downstream CDN is able (and
willing) to accept the delegated content request and to allow the willing) to accept the delegated content request. It also allows the
downstream CDN to control what the upstream Request Routing function downstream CDN to control what should be returned to the User Agent
should return to the User Agent in the redirection message. in the redirection message by the upstream Request Routing function .
The CDNI Request Routing interface is therefore a fairly The CDNI Request Routing interface is therefore a fairly
straightforward request/response interface and could be implemented straightforward request/response interface and could be implemented
over any number of request/response protocols. For example, it may over any number of request/response protocols. For example, it may
be implemented as a WebService using one of the common WebServices be implemented as a WebService using one of the common WebServices
methodologies (XML-RPC, HTTP query to a known URI, etc.). This methodologies (XML-RPC, HTTP query to a known URI, etc.). This
removes the need for the CDNI working group to define a new protocol removes the need for the CDNI working group to define a new protocol
for the request/response element of the CDNI Request Routing for the request/response element of the CDNI Request Routing
interface. interface.
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