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Content Delivery Networks                                     J. Seedorf
Interconnection                                                      NEC
Internet-Draft                                             March 5, 2012
Intended status: Informational
Expires: September 6, 2012


  Infrastructure-to-application information exposure from an ALTO-CDNI
                              Perspective
              draft-seedorf-i2aex-alto-cdni-perpective-00

Abstract

   Recently, there has been a discussion on "Infrastructure-to-
   Application Information Exposure" and the related communications
   requirements in fully controlled (e.g. data centers) or partially
   controlled environments (e.g.  CDN).  One possibility to expose
   infrastructure information to applications in the aforementioned
   environments is to use yet-to-be-defined ALTO extensions.  This draft
   discusses requirements for such ALTO extensions for a specific use
   case: Request Routing in CDN Interconnection (CDNI).

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on September 6, 2012.

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
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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   carefully, as they describe your rights and restrictions with respect
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Useful Extensions to ALTO to facilitate CDNI Request
       Routing with ALTO  . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Security Considerations  . . . . . . . . . . . . . . . . . . .  6
   4.  Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   5.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  8
   6.  Informative References . . . . . . . . . . . . . . . . . . . .  9
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 10


































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1.  Introduction

   Recently, there has been a discussion on "Infrastructure-to-
   Application Information Exposure" and the related communications
   requirements in fully controlled (e.g. data centers) or partially
   controlled environments (e.g.  CDNs) [I-D.marocco-alto-next].  One
   possibility to expose infrastructure information to applications in
   the aforementioned environments is to use ALTO
   [I-D.ietf-alto-protocol], or rather extension to ALTO which are yet
   to be investigated and specified [I-D.marocco-alto-next].

   Network Service Providers (NSPs) are currently considering to deploy
   Content Delivery Networks (CDNs) within their networks.  As a
   consequence of this development, there is a need for interconnecting
   these local CDNs.  The necessary interfaces for inter-connecting CDNs
   are currently being defined in the Content Delivery Networks
   Interconnection (CDNI) WG [I-D.ietf-cdni-requirements]
   [I-D.ietf-cdni-problem-statement] [I-D.ietf-cdni-use-cases].  Among
   other protocols, ALTO has been suggested to facilitate downstream CDN
   selection in the context of CDNI request routing [refs.altocdni],
   i.e.  ALTO is currently a candidate protocol for "Footprint and
   Capabilities Advertisment" within CDNI Request Routing.

   This document discusses what extensions to ALTO would be useful in
   case ALTO is used as a protocol within CDNI request routing, and in
   particular within the "Footprint and Capabilities Advertisment" part
   of the CDNI request routing interface.  The discussion is based on
   the suggested extensions to ALTO proposed in [I-D.marocco-alto-next]
   and the examples of how ALTO could be used for downstream CDN
   selection within CDNI request routing in [refs.altocdni].





















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2.  Useful Extensions to ALTO to facilitate CDNI Request Routing with
    ALTO

   In the following, we assume the following scenario of using ALTO for
   selecting a downstream CDN [refs.altocdni]: Each downstream CDN
   provider hosts an ALTO server which provides ALTO information (i.e.
   ALTO network maps and ALTO cost maps [I-D.ietf-alto-protocol]) to an
   ALTO client at the upstream CDN provider.  A network map provided by
   each of several candidate downstream CDNs can provide information to
   the upstream CDN provider regarding the geopgraphical coverage, the
   location of "surrogates", or similar.  In addition, an ALTO cost map
   can provide an upstream CDN provider information about the ''cost''
   of delivering certain content via the downstream CDN which provided
   such a cost map.  ''Cost'' in this context is a generic term; many
   types of costs are possible and can be useful in the context of CDNI
   request routing, e.g. average link load, expected delay, or monetary
   costs.

   As an example, an upstream CDN (uCDN) receives a request from an end
   user.  Based on the IP-address of the end user, uCDN determines that
   it is possible to deliver the content from one of several candidate
   downstream CDNs (dCDN-a, dCDN-b, and dCDN-c).  Assume that only the
   ALTO network maps provided by dCDN-a and dCDN-c indicate that these
   downstream CDNs can deliver content for the location of the end user
   requesting content.  In this case, the ALTO costs maps provide useful
   information to the upstream CDN, uCDN, in order to make a selection
   decision regarding either dCDN-a or dCDN-c.

   From the perspective of the given scenario and example, the following
   proposed extensions to ALTO would be beneficial to facilitate CDNI
   request routing with ALTO:

   o  Server-initiated Notifications and Incremental Updates: In case
      the footprint or the capabilities of a downstream CDN change
      abruptly (i.e. unexpectedly from the perspective of an upstream
      CDN), server initiated notifications would enable a dCDN to
      directly inform an upstream CDN about such changes.  Consider the
      case where - due to failure - part of the footprint of the dCDN is
      not functioning, i.e. the CDN cannot serve content to such clients
      with reasonable QoS.  Without server-initiated notifications, the
      uCDN might still use a very recent network and cost map from dCDN,
      and therefore redirect request to dCDN which it cannot serve.
      Similarly, the possibility for incremental updates would enable
      efficient conveyance of the aforementioned (or similar) status
      changes by the dCDN to the uCDN.

   o  Content Availability on Hosts: A dCDN might want to express CDN
      capabilties in terms of certain content types (e.g. codecs/



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      formats, or content from certain content providers).  A new
      endpoint property for ALTO that would be able to express such
      "content availability" would enable a dCDN to make available such
      information to an upstream CDN.  This would enable a uCDN to
      determine if a given dCDN actually has the capabilities for a
      given request with respect to the type of content requested.

   o  Resource Availability on Hosts or Links: The capabilities on links
      (e.g. maximum bandwidth) or caches (e.g. average load) might be
      useful information for an upstream CDN for optimized dowmstream
      CDN selection.  For instance, if a uCDN receives a streaming
      request for content with a certain bitrate, it needs to know if it
      is likely that a dCDN can fulfill such stringent application-level
      requirements (i.e. can be expected to have enough consistent
      bandwidth) before it redirects the request.  In general, if ALTO
      could convey such information via new endpoint properties, it
      would enable more sophisticated means for downstream CDN selection
      with ALTO.

































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3.  Security Considerations

   Security Considerations will be discussed in a future version of this
   document.















































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4.  Conclusion

   Recently, there has been a discussion on "Infrastructure-to-
   Application Information Exposure" and the related communications
   requirements in fully controlled (e.g. data centers) or partially
   controlled environments (e.g.  CDN).  One possibility to expose
   infrastructure information to applications in the aforementioned
   environments is to use yet-to-be-defined ALTO extensions.  This draft
   considered requirements for such ALTO extensions for a specific use
   case: Request Routing in CDN Interconnection (CDNI).  This document
   discussed useful extensions to ALTO in this context, i.e. what
   extensions would be beneficial from the CDNI perspective and why.







































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5.  Acknowledgements

   Jan Seedorf is partially supported by the COAST project (COntent
   Aware Searching, retrieval and sTreaming, http://www.coast-fp7.eu), a
   research project supported by the European Commission under its 7th
   Framework Program (contract no. 248036).  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 COAST project or
   the European Commission.









































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6.  Informative References

   [I-D.ietf-alto-protocol]
              Penno, R., Alimi, R., and Y. Yang, "ALTO Protocol",
              draft-ietf-alto-protocol-10 (work in progress),
              October 2011.

   [I-D.ietf-cdni-problem-statement]
              Niven-Jenkins, B., Faucheur, F., and N. Bitar, "Content
              Distribution Network Interconnection (CDNI) Problem
              Statement", draft-ietf-cdni-problem-statement-03 (work in
              progress), January 2012.

   [I-D.ietf-cdni-requirements]
              Leung, K. and Y. Lee, "Content Distribution Network
              Interconnection (CDNI) Requirements",
              draft-ietf-cdni-requirements-02 (work in progress),
              December 2011.

   [I-D.ietf-cdni-use-cases]
              Gilles, B., Watson, G., Ma, K., Eardley, P., Emile, S.,
              and T. Burbridge, "Use Cases for Content Delivery Network
              Interconnection", draft-ietf-cdni-use-cases-03 (work in
              progress), January 2012.

   [I-D.marocco-alto-next]
              Marocco, E. and V. Gurbani, "Extending the Application-
              Layer Traffic Optimization (ALTO) Protocol",
              draft-marocco-alto-next-00 (work in progress),
              January 2012.

   [refs.altocdni]
              Seedorf, J., "ALTO for CDNi Request Routing",
              draft-seedorf-cdni-request-routing-alto-00 (work in
              progress), March 2012.
















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Author's Address

   Jan Seedorf
   NEC Laboratories Europe, NEC Europe Ltd.
   Kurfuersten-Anlage 36
   Heidelberg  69115
   Germany

   Phone: +49 (0) 6221 4342 221
   Email: jan.seedorf@neclab.eu
   URI:   http://www.neclab.eu








































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