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Network Working Group                                       O. Finkelman
Internet-Draft                                                     Qwilt
Intended status: Standards Track                               S. Mishra
Expires: November 16, 2018                                       Verizon
                                                            May 15, 2018


                  CDNI SVA Request Routing Extensions
               draft-finkelman-cdni-rr-sva-extensions-01

Abstract

   The Open Caching working group of the Streaming Video Alliance is
   focused on the delegation of video delivery requests from commercial
   CDNs to a caching layer at the ISP.  In that aspect, Open Caching is
   a specific use case of CDNI, where the commercial CDN is the upstream
   CDN (uCDN) and the ISP caching layer is the downstream CDN (dCDN).

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 https://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 November 16, 2018.

Copyright Notice

   Copyright (c) 2018 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



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   (https://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  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Redirect Target Address Capability Object . . . . . . . . . .   3
     2.1.  DnsTarget . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.2.  HttpTarget  . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Fallback Target Address Metadata  . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     4.1.  CDNI Payload Types  . . . . . . . . . . . . . . . . . . .   8
       4.1.1.  CDNI FCI RedirectTarget Payload Type  . . . . . . . .   8
       4.1.2.  CDNI MI FallbackTarget Payload Type . . . . . . . . .   9
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   7.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   This document defines objects needed for Open Caching request
   routing.  For that purpose it extends CDNI metadata [RFC8006] and
   CDNI Footprint and Capabilities [RFC8008].  For consistency, this
   document follows the CDNI notation of uCDN (the commercial CDN) and
   dCDN (the ISP caching layer).

   This document also registers CDNI Payload Types [RFC7736] for the
   defined objects:

   o  Redirect Target Capability (for dCDN advertising redirect target
      address)

   o  Fallback Target Metadata (for uCDN configuring fallback target
      address)







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1.1.  Terminology

   This document reuses the terminology defined in [RFC6707], [RFC8006],
   [RFC8007], and [RFC8008].

   Additionally, the following terms are used throughout this document
   and are defined as follows:

   o  SVA - Streaming Video Alliance

   o  OC - SVA Open Caching

   o  RR - Request Router

   o  CP - Content Provider

2.  Redirect Target Address Capability Object

   Iterative request redirect as defined in section 1.1 of [RFC7336]
   requries the provisioning of a redirect target address to be used by
   the uCDN in order to redirect to the dCDN.  The redirect target is
   defined in this document as part of the Footprint and Capabilities
   interface.

   Use cases

   o  Footprint: The dCDN may want to have a different target per
      footprint.  Note that a dCDN may spread across multiple
      geographies.  This makes it easier to route client request to a
      nearby request router.  Though this can be achieved using a single
      canonical name and Geo DNS, that approach has limitations, for
      example a client may be using third party DNS resolver, making it
      impossible for the redirector to detect where the client is
      located, or Geo DNS granularity may be to rough for the
      requirement of the application.

   o  Scaling: The dCDN may choose to scale its request routing service
      by deploying more request routers in new locations and advertise
      them via an updatable interface like the FCI.

   The Redirect Target capability object is used to indicate the target
   address the uCDN should use in order to redirect a client to the
   dCDN.  A target may be attached to a specific uCDN host, or a list of
   uCDN hosts, or it can be set globally for all the hosts of the uCDN.

   When dCDN is attaching the redirect target to a specific uCDN host or
   a list of uCDN hosts, the dCDN MUST advertise them within the
   Redirect Target Capabilty object as "redirecting-hosts".  In that



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   case, the uCDN can redirect to that dCDN address, only if the request
   is of one of these uCDN hosts.

   A redirect target for DNS redirection is the FQDN to be used as a
   CNAME for the uCDN host (see [RFC1034]).

   A redirect target for HTTP redirection is the hostname to be used as
   the first path segment in an absolute URI which is used as the
   Location header of the HTTP rediret response (see section 7.1.2 of
   [RFC7231]).

      Property: redirecting-hosts

         Description: One or more uCDN hosts that this redirect target
         is attached to.  A redirecting host SHOULD be a host that was
         published in a HostMatch object by the uCDN as defined in
         section 4.1.2 of [RFC8006].

         Type: A list of Endpoint objects (see section 4.3.3 of
         [RFC8006])

         Mandatory-to-Specify: No.  If not present, or empty, the
         redirect target applies to all hosts of the redirecting uCDN.

      Property: dns-target

         Description: Target address for DNS CNAME delegation.

         Type: DnsTarget object (see Section 2.1)

         Mandatory-to-Specify: No. but at least one of "dns-target" or
         "http-target" MUST be present and non empty.

      Property: http-target

         Description: Target URL for HTTP redirect.

         Type: HttpTarget object (see Section 2.2)

         Mandatory-to-Specify: No. but at least one of "dns-target" or
         "http-target" MUST be present and non empty.

   Example of Redirect Target Capability object that advertises a dCDN
   target address which is attached to a specific list of uCDN
   "redirecting-hosts".  A uCDN host that is included in that list can
   redirect to the advertised dCDN redirect target.





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       {
        "capabilities": [
          {
            "capability-type": "FCI.RedirectTarget",
            "capability-value": {
                "redirecting-hosts": [
                   "a.service123.ucdn.example.com",
                   "b.service123.ucdn.example.com"
                ]
                "dns-target": {
                   "host": "service123.ucdn.example.dcdn.com"
                }
                "http-target": {
                    <Properties of an HttpTarget object>
                }
            },
            "footprints": [
              <Footprint objects>
            ]
          }
        ]
       }

2.1.  DnsTarget

   The DnsTarget object is the target address for CNAME delegation from
   the uCDN to the dCDN.

      Property: host

         Description: The host property is a hostname, without a port
         number.

         Type: Endpoint object as defined in section 4.3.3 of [RFC8006]
         with the limitation that it MUST only be a hostname, and it
         MUST NOT include a port number.

         Mandatory-to-Specify: Yes.

2.2.  HttpTarget

   The HttpTarget object is the target address for http redirection from
   the uCDN to the dCDN.

      Property: host

         Description: Hostname or IP address and optional port, i.e.,
         the host and port as described in section 3.2 of [RFC3986].



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         Type: Endpoint object as defined in section 4.3.3 of [RFC8006].

         Mandatory-to-Specify: Yes.

      Property: path-prefix

         Description: A path prefix for the HTTP redirect.  The original
         path is appended after this prefix.

         Type: A prefix of a path-absolute as defined in section 3.3 of
         [RFC3986].  The prefix MUST end with trailing slash, to
         indicate the end of the last path segment in the prefix.

         Mandatory-to-Specify: No.  If this property is absent or empty,
         the uCDN MUST NOT prepend a path prefix to the original content
         path.

      Property: include-redirecting-host

         Description: A flag indicating weather or not to include the
         redirecting host as the first path segment after the path-
         prefix.  In case this flag is true and a "path-prefix" is used,
         the uCDN redirecting host MUST be added as a separate path
         segment after the path-prefix and before the original URL path.
         In case this flag is true and there is no path-prefix, the uCDN
         redirecting host MUST be prepended as the first path segment in
         the redirect URL.

         Type: Boolean.

         Mandatory-to-Specify: No.  Default value is False.

   Example of HttpTarget object with a path-prefix and include-
   redirecting-host:

    {
        "host": "us-east1.dcdn.com",
        "path-prefix": "/cache/1/",
        "include-redirecting-host": true
    }

   Example of a HTTP request for content at uCDN host
   "a.service123.ucdn.example.com" and the corresponding HTTP response
   with Location header used for redirecting the client to the dCDN
   using the the http-target in the above example:






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    Request:
    GET /vod/1/movie.mp4 HTTP/1.1
    Host: a.service123.ucdn.example.com

    Response:
    HTTP/1.1 302 Found
    Location: http://us-east1.dcdn.com/cache/1/
    a.service123.ucdn.example.com/vod/1/movie.mp4

3.  Fallback Target Address Metadata

   Open Caching requires that the uCDN should provide fallback target
   server to the dCDN to be used in cases where the dCDN cannot properly
   handle the request.  To avoid redirect loops, the fallback target
   server's address at the uCDN MUST be differnet than the original
   address at the uCDN from which the client was redirected to the dCDN.
   The uCDN MUST avoid further redirection when receiving the client
   request at the fallback target.  The fallback target is defined as a
   generic metadata object (see section 3.2 of [RFC8006])

   Use cases

   o  Failover: A dCDN request router receives a request but has no
      caches to which it can route the request to.  This can happen in
      the case of failures, or temporary network overload.  In these
      cases, the router may choose to redirect the request back to the
      uCDN fallback address.

   o  Error: A cache may receive a request that it cannot properly
      serve, for example, some of the metadata objects for that service
      were not properly acquired.  In this case the cache may resolve to
      redirect back to uCDN.

   The Fallback target metadata object is used to indicate the target
   address the dCDN should use in order to redirect a client back to the
   uCDN.  Fallback target is represented as endpoint objects as defined
   in section 4.3.3 of [RFC8006].

   The uCDN fallback target address may be used as a DNS CNAME in case
   of DNS redirection mode or a host name for HTTP redirect, in the case
   of HTTP redirection mode.

   When using HTTP redirect to route a client request back to the uCDN,
   it is the dCDN responsibility to use the original URL path as the
   client would have used for the original uCDN request, stripping, if
   needed, the dCDN path-prefix and the uCDN host name from the redirect
   URL which is used for requesting the content from the dCDN.




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      Property: host

         Description: Target address to which the dCDN can redirect the
         client.

         Type: Endpoint object as defined in section 4.3.3 of [RFC8006]
         with the limitation that in case of DNS delegation, it MUST
         only be a hostname, and it MUST NOT include a port number.

         Mandatory-to-Specify: Yes.

   Example of MI.FallbackTarget Metadata object (which contains two
   fallback-address objects) that describes which hosts addreses in the
   uCDN the dCDN should use in order to redirect the client back to a
   fallback address at the uCDN.

   {
        "generic-metadata-type": "MI.FallbackTarget",
        "generic-metadata-value":
          {
            "host": "fallback-a.service123.ucdn.example"
          }
   }

4.  IANA Considerations

4.1.  CDNI Payload Types

   This document requests the registration of the following CDNI Payload
   Types under the IANA CDNI Payload Type registry defined in [RFC7736]:

                  +--------------------+---------------+
                  | Payload Type       | Specification |
                  +--------------------+---------------+
                  | FCI.RedirectTarget | RFCthis       |
                  | MI.FallbackTarget  | RFCthis       |
                  +--------------------+---------------+

   [RFC Editor: Please replace RFCthis with the published RFC number for
   this document.]

4.1.1.  CDNI FCI RedirectTarget Payload Type

   Purpose: The purpose of this payload type is to distinguish
   RedirectTarget FCI objects

   Interface: FCI




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   Encoding: see Section 2

4.1.2.  CDNI MI FallbackTarget Payload Type

   Purpose: The purpose of this payload type is to distinguish
   FallbackTarget MI objects (and any associated capability
   advertisement)

   Interface: MI/FCI

   Encoding: see Section 3

5.  Security Considerations

   This specification is in accordance with the CDNI Metadata Interface
   and the CDNI Request Routing: Footprint and Capabilities Semantics.
   As such, it is subject to the security considerations as defined in
   [RFC8006] and [RFC8008] respectively.

6.  Acknowledgements

   TBD.

7.  Contributors

   TBD.

8.  References

8.1.  Normative References

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [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,
              <https://www.rfc-editor.org/info/rfc3986>.







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   [RFC7231]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
              DOI 10.17487/RFC7231, June 2014,
              <https://www.rfc-editor.org/info/rfc7231>.

   [RFC8006]  Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
              "Content Delivery Network Interconnection (CDNI)
              Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
              <https://www.rfc-editor.org/info/rfc8006>.

   [RFC8007]  Murray, R. and B. Niven-Jenkins, "Content Delivery Network
              Interconnection (CDNI) Control Interface / Triggers",
              RFC 8007, DOI 10.17487/RFC8007, December 2016,
              <https://www.rfc-editor.org/info/rfc8007>.

   [RFC8008]  Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
              R., and K. Ma, "Content Delivery Network Interconnection
              (CDNI) Request Routing: Footprint and Capabilities
              Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
              <https://www.rfc-editor.org/info/rfc8008>.

8.2.  Informative References

   [RFC6707]  Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
              Distribution Network Interconnection (CDNI) Problem
              Statement", RFC 6707, DOI 10.17487/RFC6707, September
              2012, <https://www.rfc-editor.org/info/rfc6707>.

   [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, <https://www.rfc-editor.org/info/rfc7336>.

   [RFC7736]  Ma, K., "Content Delivery Network Interconnection (CDNI)
              Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
              December 2015, <https://www.rfc-editor.org/info/rfc7736>.

Authors' Addresses

   Ori Finkelman
   Qwilt
   6, Ha'harash
   Hod HaSharon  4524079
   Israel

   Phone: +972-72-2221647
   Email: orif@qwilt.com




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   Sanjay Mishra
   Verizon
   13100 Columbia Pike
   Silver Spring, MD  20904
   USA

   Email: sanjay.mishra@verizon.com












































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