CDNI R. Krishnan Internet Draft Brocade Communications Intended status: Informational M. Li Expires: January 2013 B. Khasnabish ZTE Corporation July 30, 2012 Long Tail personalized content delivery over CDN Interconnections draft-krishnan-cdni-long-tail-00.txt Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, and it may not be published except as an Internet-Draft. This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, except to publish it as an RFC and to translate it into languages other than English. 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Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any Krishnan Expires January 30, 2013 [Page 1] Internet-Draft Long tail content delivery over CDNI July 2012 time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on January 30, 2009. Copyright Notice Copyright (c) 2012 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. 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. Abstract The content desire of users is evolving from most popular to long tail personalized content. This document presents the issues and suggests solutions in delivering long tail personalized content in CDN Interconnection scenarios. Table of Contents 1. Introduction...................................................3 2. Conventions used in this document..............................3 3. Optimizing delivery of long tail personalized content over CDN Interconnections..................................................3 Krishnan Expires January 30, 2013 [Page 2] Internet-Draft Long tail content delivery over CDNI July 2012 3.1. No Caching in CDNs........................................3 3.2. Benefits of HTTP Adaptive Streaming.......................5 3.3. Caching in end user device................................5 4. References.....................................................6 4.1. Normative References......................................6 4.2. Informative References....................................6 1. Introduction The content desire of users is evolving from most popular to long tail personalized content. Typically, the CDNi interface between CDNs is a long-haul backbone network where bandwidth is premium. Popular content is typically shared by many users and is very amenable to caching. A single copy of the content is delivered across CDNi to the content cache; the content is delivered to multiple users from the content cache. Thus, popular content delivery can be scaled to a number of users. On the other hand, long tail personalized content is typically not shared by many users and not amenable to caching. Also, there is heavy asymmetric usage of the network between peak and quiet hours. These create unique bandwidth challenge across CDNi. This document suggests solutions for optimizing delivery of long tail personalized content in CDN Interconnection scenarios. 2. Conventions used in this document 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]. This document reuses the terminology defined in: [I-D.ietf-cdni-problem-statement-06], [I-D.ietf-cdni-requirements-03], [I-D.ietf-cdni-framework-00], and [I-D.ietf-cdni-use-cases-08]. 3. Optimizing delivery of long tail personalized content over CDN Interconnections 3.1. No Caching in CDNs Long tail personalized content is typically not shared by many users and not amenable to caching. Avoiding caching in the CDNs has the following benefits 1) Better cache utilization 2) Avoid unnecessary Krishnan Expires January 30, 2013 [Page 3] Internet-Draft Long tail content delivery over CDNI July 2012 HTTP redirection. Using content usage analytics tools, the content provider determines that the content of interest belongs to the category of long tail personalized and not amenable to caching. This information is made available in the form of per content URL metadata to the uCDN. The example below illustrates how this information can be used to avoid caching in the CDNs. Krishnan Expires January 30, 2013 [Page 4] Internet-Draft Long tail content delivery over CDNI July 2012 Referring to the example in Fig. 2, Section 3 [I-D.ietf-cdni- framework]; it shows Operator A as the upstream CDN (uCDN) and Operator B as the downstream CDN (dCDN), where the former has a relationship with a content provider and the latter being the best CDN to deliver content to the end-user. Referring to the HTTP example in Fig. 3, Section 3.2 [I-D.ietf-cdni-framework]; Step 2: A Request Router for Operator A processes the HTTP request and recognizes that the end-user is best served directly by the origin server without any caching--and so it returns a 302 redirect message for a new URL containing the path to the content origin server (the current behavior for a cached CDN is to construct a new URL by "stacking" Operator B's distinguished CDN-domain on the front of the original URL). 3.2. Benefits of HTTP Adaptive Streaming Recalling the points we discussed before 1) Long tail personalized content is not amenable to caching 2) There is heavy asymmetric usage of the network between peak and quiet hours, where the peak hour load is much higher than the quiet hour load. These create unique bandwidth challenges across CDNi. HTTP Adaptive Streaming (HAS), which can adapt to network congestion, is ideally suited for delivering long tail personalized content. [I-D.krishnan-cdni-tm-has] recommends traffic management techniques which can offer the best adaptive streaming performance over CDN interconnections. 3.3. Caching in end user device Caching in the end user device can be used to address the challenges created by streaming delivery of long tail personalized content over CDNi. This introduces a new model for long tail personalized content delivery. The various components of this model can be defined as 1) End user chooses the content to watch 2) The content is downloaded in the background and cached in the end user device 3) End user is notified of content availability. SDN techniques for CDNi [I-D.shin- cdni-request-routing-sdn] can be used to optimize the process of caching in the end user device. Using the SDN techniques, which involve end-to-end resource awareness, it is possible to predict the approximate time at which the content would be available to the end user when the end user chooses to watch the content. This model is typically applicable for long form content where the overhead in managing a background download is justifiable. Caching in the end user device can have potential DRM issues which can be addressed using the following techniques 1) The content can be accessed by the end user only for playback 2) The content has a time Krishnan Expires January 30, 2013 [Page 5] Internet-Draft Long tail content delivery over CDNI July 2012 expiry after which it destructs itself 3) In the case of end user device loss, the content destructs itself. 4. References 4.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, Internet Mail Consortium and Demon Internet Ltd., November 1997. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, Internet Mail Consortium and Demon Internet Ltd., November 1997. 4.2. Informative References [I-D.ietf-cdni-framework]L. Peterson et al., "Framework for CDN Interconnection", April 2012. [I-D.ietf-cdni-problem-statement]B. Niven-Jenkins et al., "Content Distribution Network Interconnection (CDNi) Problem Statement", May 2012. [I-D.ietf-cdni-requirements]K. Leung et al., "Content Distribution Network Interconnection (CDNi) Requirements", December 2011. [I-D.ietf-cdni-use-cases]Bertrand, G. et al., "Use Cases for Content Delivery Network Interconnection", June 2012. [I-D.krishnan-cdni-has-tm] Krishnan, R. et al., "Traffic management models for adaptive-streaming-aware CDN Interconnection", July 2012. [I-D.shin-cdni-request-routing-sdn] Shin et al., "CDNI Request Routing with SDN", July 2012. Authors' Addresses Ram Krishnan Brocade Communications Krishnan Expires January 30, 2013 [Page 6] Internet-Draft Long tail content delivery over CDNI July 2012 San Jose, 95134, USA Phone: +001-408-406-7890 Email: ramk@brocade.com Mian Li ZTE Corporation Nanjing, 210012 China Phone: Email: li.mian@zte.com.cn Bhumip Khasnabish ZTE Corporation New Jersey, 07960, USA Phone: +001-781-752-8003 Email: bhumip.khasnabish@zteusa.com Krishnan Expires January 30, 2013 [Page 7]