GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc8804



Internet Engineering Task Force (IETF) O. Finkelman Request for Comments: 8804 Qwilt Category: Standards Track S. Mishra ISSN: 2070-1721 Verizon

                                                        September 2020
  Content Delivery Network Interconnection (CDNI) Request Routing
                             Extensions

Abstract

 Open Caching architecture is a use case of Content Delivery Network
 Interconnection (CDNI) in which the commercial Content Delivery
 Network (CDN) is the upstream CDN (uCDN) and the ISP caching layer
 serves as the downstream CDN (dCDN).  This document defines
 extensions to the CDNI Metadata Interface (MI) and the Footprint &
 Capabilities Advertisement interface (FCI).  These extensions are
 derived from requirements raised by Open Caching but are also
 applicable to CDNI use cases in general.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8804.

Copyright Notice

 Copyright (c) 2020 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
 (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
   1.1.  Terminology
   1.2.  Requirements Language
 2.  Redirect Target Capability
   2.1.  DNS Redirect Target
   2.2.  HTTP Redirect Target
   2.3.  Properties of Redirect Target Capability Object
   2.4.  DnsTarget Object
     2.4.1.  DnsTarget Example
   2.5.  HttpTarget Object
     2.5.1.  HttpTarget Example
   2.6.  Usage Example
 3.  Fallback Target Server Address
   3.1.  Properties of Fallback Target Generic Metadata Object
   3.2.  Usage Example
   3.3.  uCDN Addressing Considerations
 4.  IANA Considerations
   4.1.  CDNI Payload Types
     4.1.1.  CDNI FCI RedirectTarget Payload Type
     4.1.2.  CDNI MI FallbackTarget Payload Type
 5.  Security Considerations
   5.1.  Confidentiality and Privacy
 6.  References
   6.1.  Normative References
   6.2.  Informative References
 Acknowledgements
 Authors' Addresses

1. Introduction

 The Streaming Video Alliance [SVA] is a global association that works
 to solve streaming video challenges in an effort to improve end-user
 experience and adoption.  The Open Caching Working Group [OCWG] of
 the Streaming Video Alliance [SVA] is focused on the delegation of
 video delivery requests from commercial CDNs to a caching layer at
 the ISP's network.  Open Caching architecture 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).  The Open Caching
 Request Routing Functional Specification [OC-RR] defines the Request
 Routing process and the interfaces that are required for its
 provisioning.  This document defines the CDNI metadata object
 [RFC8006] and the CDNI Footprint and Capabilities object [RFC8008]
 that are required for Open Caching Request Routing:
  • Redirect Target Capability (for dCDN advertising redirect target

address)

  • Fallback Target Metadata (for uCDN configuring fallback target

address)

 This document also registers CDNI Payload Types [RFC7736] for these
 defined objects.
 For consistency with other CDNI documents, this document follows the
 CDNI convention of uCDN (upstream CDN) and dCDN (downstream CDN) to
 represent the commercial CDN and ISP caching layer, respectively.

1.1. Terminology

 The following terms are used throughout this document:
 FQDN    Fully Qualified Domain Name
 CDN     Content Delivery Network
 Additionally, this document reuses the terminology defined in
 [RFC6707], [RFC7336], [RFC8006], [RFC8007], and [RFC8008].
 Specifically, we use the following CDNI acronyms:
 FCI     Footprint & Capabilities Advertisement interface (see
         [RFC8008])
 MI      Metadata Interface (see [RFC8006])
 uCDN    Upstream CDN (see [RFC7336])
 dCDN    Downstream CDN (see [RFC7336])
 RT      Redirection Target.  Endpoint for redirection from uCDN to
         dCDN.
 RR      Request Router.  An element responsible for routing user
         requests, typically using HTTP redirect or DNS CNAME,
         depending on the use case.

1.2. Requirements Language

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
 capitals, as shown here.

2. Redirect Target Capability

 Iterative CDNI Request Redirection is defined in Section 1.1 of
 [RFC7336] and elaborated by examples in Sections 3.2 and 3.4 of
 [RFC7336].  A Redirection Target (RT) is defined in Section 2 of
 [RFC7975] for Recursive Request Redirection as:
 |  The endpoint to which the User Agent is redirected.  In CDNI, an
 |  RT may point to a number of different components, some examples
 |  include a surrogate in the same CDN as the request router, a
 |  request router in a dCDN, or a surrogate in a dCDN.
 In this document, we adopt the same definition of the RT for the
 Iterative Request Redirect use case.  This use case requires the
 provisioning of the RT address to be used by the uCDN in order to
 redirect to the dCDN.  RT addresses can vary between different
 footprints (for example, between different regions), and they may
 also change over time (for example, as a result of network problems).
 Given this variable and dynamic nature of the redirect target
 address, it may not be suitable to advertise it during bootstrap.  A
 more dynamic and footprint-oriented interface is required.
 Section 4.3 of [RFC7336] suggests that it could be one of the roles
 of the FCI [RFC8008].  Following this suggestion, we have therefore
 chosen to use the CDNI Footprint & Capabilities Advertisement
 interface for redirect target address advertisement.
 Use cases:
  • 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 requests to a
    nearby request router.  Though this can be achieved using a single
    canonical name and "Geo DNS", such that in different geographies
    the same hostname is resolved to different IP address, that
    approach has limitations; for example, a client may be using a
    third-party DNS resolver, making it impossible for the redirector
    to detect where the client is located, or Geo DNS granularity may
    be too rough for the requirement of the application.
  • 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, attached to
 a list of uCDN hosts, or used globally for all the hosts of the uCDN.
 When a dCDN is attaching the redirect target to a specific uCDN host
 or a list of uCDN hosts, the dCDN MUST advertise the hosts within the
 Redirect Target capability object as "redirecting-hosts".  In this
 case, the uCDN can redirect to that dCDN address, only if the User
 Agent request was to one of these uCDN hosts.
 If the Redirect Target capability object does not contain a target or
 the target is empty, the uCDN MUST interpret it as "no target
 available for these uCDN hosts for the specified footprint".  In case
 such a target was already advertised in a previous FCI object, the
 uCDN MUST interpret it as an update that deletes the previous
 redirect target.

2.1. DNS Redirect Target

 A redirect target for DNS redirection is an FQDN used as an alias in
 a CNAME record response (see [RFC1034]) of the uCDN DNS router.  Note
 that DNS routers make routing decisions based on either the DNS
 resolver's IP address or the client IP subnet when EDNS0 client-
 subnet (ECS) is used (see [RFC7871]).  The dCDN may choose to
 advertise redirect targets and footprints to cover both cases, such
 that the uCDN resolution would route the DNS query to different dCDN
 CNAMEs according to client subnet or dCDN resolver IP address.  This
 method further allows the dCDN DNS to optimize the resolution by
 localizing the target CNAMEs.  A uCDN implementation SHOULD prefer
 routing based on client IP subnet when the ECS option is present.  A
 dCDN implementation using the ECS option MUST be aware of the privacy
 drawbacks listed in Section 2 of [RFC7871] and SHOULD follow the
 guidelines provided in Section 11.1 of [RFC7871].

2.2. HTTP Redirect Target

 A redirect target for HTTP redirection is the URI to be used as the
 value for the Location header of an HTTP redirect 3xx response,
 typically a 302 (Found) (see Section 7.1.2 of [RFC7231] and
 Section 6.4 of [RFC7231]).

2.3. Properties of Redirect Target Capability Object

 The Redirect Target capability object consists of the following
 properties:
 Property:  redirecting-hosts
    Description:  One or more uCDN hosts to which this redirect target
       is attached.  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 absent or empty, the redirect
       target applies to all hosts of the redirecting uCDN.
 Property:  dns-target
    Description:
       Target CNAME record for DNS redirection.
    Type:
       DnsTarget object (see Section 2.4)
    Mandatory-to-Specify:
       No.  If the dns-target is absent or empty, the uCDN MUST
       interpret it as "no dns-target available".
 Property:  http-target
    Description:
       Target URI for an HTTP redirect.
    Type:
       HttpTarget object (see Section 2.5)
    Mandatory-to-Specify:
       No.  If the http-target is absent or empty, the uCDN MUST
       interpret it as "no http-target available".
 The following is an example of a Redirect Target capability object
 serialization that advertises a dCDN target address that 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.  The capabilities object is serialized as a JSON object as
 defined in Section 5.1 of [RFC8008].
 {
   "capabilities": [
     {
       "capability-type": "FCI.RedirectTarget",
       "capability-value": {
           "redirecting-hosts": [
              "a.service123.ucdn.example.com",
              "b.service123.ucdn.example.com"
           ],
           "dns-target": {
              "host": "service123.ucdn.dcdn.example.com"
           },
           "http-target": {
               "host": "us-east1.dcdn.example.com",
               "path-prefix": "/cache/1/",
               "include-redirecting-host": true
           }
       },
       "footprints": [
           <Footprint objects>
       ]
     }
   ]
 }

2.4. DnsTarget Object

 The DnsTarget object gives the target address for the DNS response to
 delegate from the uCDN to the dCDN.
 Property:  host
    Description:  The host property is a hostname or an IP address,
       without a port number.
    Type:  Endpoint object as defined in Section 4.3.3 of [RFC8006],
       with the limitation that it SHOULD NOT include a port number
       and, in case a port number is present, the uCDN MUST ignore it.
    Mandatory-to-Specify:  Yes.

2.4.1. DnsTarget Example

 The following is an example of the DnsTarget object:
 {
    "host": "service123.ucdn.dcdn.example.com"
 }
 The following is an example of a DNS query for uCDN address
 "a.service123.ucdn.example.com" and the corresponding CNAME
 redirection response:
 Query:
 a.service123.ucdn.example.com:
 type A, class IN
 Response:
 NAME: a.service123.ucdn.example.com, TYPE: CNAME, CLASS: IN,
 TTL: 120, RDATA: service123.ucdn.dcdn.example.com

2.5. HttpTarget Object

 The HttpTarget object gives the necessary information to construct
 the target Location URI for HTTP redirection.
 Property:  host
    Description:  Hostname or IP address and an optional port, i.e.,
       the host and port of the authority component of the URI as
       described in Section 3.2 of [RFC3986].
    Type:  Endpoint object as defined in Section 4.3.3 of [RFC8006].
    Mandatory-to-Specify:  Yes.
 Property:  scheme
    Description:  A URI scheme to be used in the redirect response
       location construction.  When present, the uCDN MUST use the
       provided scheme in for HTTP redirection to the dCDN.
    Type:  A URI scheme as defined in Section 3.1 of [RFC3986],
       represented as a JSON string.  The scheme MUST be either "http"
       or "https".
    Mandatory-to-Specify:  No.  If this property is absent or empty,
       the uCDN request router MUST use the same scheme as was used in
       the original request before redirection.
 Property:  path-prefix
    Description:  A path prefix for the HTTP redirect Location header.
       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 a 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, i.e., the original path MUST appear in the Location URI
       right after the authority component.
 Property:  include-redirecting-host
    Description:  A flag indicating whether or not to include the
       redirecting host as the first path segment after the path-
       prefix.  If set to 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.  If set to
       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.

2.5.1. HttpTarget Example

 The following is an example of the HttpTarget object with a "scheme",
 a "path-prefix", and "include-redirecting-host" properties:
 {
    "host": "us-east1.dcdn.example.com",
    "scheme": "https",
    "path-prefix": "/cache/1/",
    "include-redirecting-host": true
 }
 The following is an example of an HTTP request for content at uCDN
 host "a.service123.ucdn.example.com" and the corresponding HTTP
 response with a Location header, used for redirecting the client to
 the dCDN, constructed according to the HttpTarget object from the
 above example:
 Request:
 GET /vod/1/movie.mp4 HTTP/1.1
 Host: a.service123.ucdn.example.com
 Response:
 HTTP/1.1 302 Found
 Location: https://us-east1.dcdn.example.com/cache/1/
 a.service123.ucdn.example.com/vod/1/movie.mp4

2.6. Usage Example

 Before requests can be routed from the uCDN to the dCDN, the CDNs
 must exchange service configurations between them.  Using the MI, the
 uCDN advertises out-of-band its hosts to the dCDN; each host is
 designated by a hostname and has its own specific metadata (see
 Section 4.1.2 of [RFC8006]).  Using the FCI, the dCDN advertises
 (also out-of-band) the redirect target address defined in Section 2.3
 for the relevant uCDN hosts.  The following is a generalized example
 of the message flow between a uCDN and a dCDN.  For simplicity, we
 focus on the sequence of messages between the uCDN and dCDN and not
 on how they are passed.
   dCDN                                                    uCDN
     +                                                       +
     |                                                       |
 (1) | MI:  host: s123.ucdn.example.com                      |
     |      host-metadata: < metadata >                      |
     <-------------------------------------------------------+
     |                                                       |
 (2) | FCI:  capability-type: FCI.RedirectTarget             |
     |       redirecting-hosts: s123.ucdn.example.com        |
     |       target host: us-east1.dcdn.example.com          |
     +------------------------------------------------------->
     |                                                       |
     |                                                       |
     +                                                       +
            Figure 1: Redirect Target Address Advertisement
 Explanation:
 (1)  The uCDN advertises a host (s123.ucdn.example.com) with the host
      metadata.
 (2)  The dCDN advertises its FCI objects to the uCDN, including a
      Redirect Target capability object that contains the redirect
      target address (us-east1.dcdn.example.com) specified for that
      uCDN host.
 Once the redirect target has been set, the uCDN can start redirecting
 user requests to the dCDN.  The following is a generic sequence of
 redirection using the host and redirect target that were advertised
 in Figure 1.
 End User                  dCDN                   uCDN RR
     +                       +                       +
     |                       |                       |
 (1) | Request sent s123.ucdn.example.com            |
     +-----------------------+----------------------->
     |                       |                       |
 (2) | Redirect to us-east1.dcdn.example.com         |
     <-----------------------+-----------------------+
     |                       |                       |
 (3) | Request us-east1.dcdn.example.com             |
     +----------------------->                       |
     |                       |                       |
 (4) | Response              |                       |
     <-----------------------+                       |
     |                       |                       |
     +                       +                       +
             Figure 2: Generic Request Redirection Sequence
 Explanation:
 (1)  The End User sends a request (DNS or HTTP) to the uCDN Request
      Router (RR).
 (2)  Using the previously advertised Redirect Target, the uCDN
      redirects the request to the dCDN.
 (3)  The End User sends a request to the dCDN.
 (4)  The dCDN either sends a response or reroutes it, for example, to
      a dCDN surrogate.

3. Fallback Target Server Address

 Open Caching requires that the uCDN provides a 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 different from the original uCDN address
 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:
  • Failover: A dCDN request router receives a request but has no

caches to which it can route the request. This can happen in the

    case of failures or temporary network overload.
  • No coverage: A dCDN request router receives a request from a

client located in an area inside the footprint but not covered by

    the dCDN caches or outside the dCDN footprint coverage.  In such
    cases, the router may choose to redirect the request back to the
    uCDN fallback address.
  • 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's "default
    action" may be to "redirect back to uCDN".
 The Fallback Target metadata object is used to indicate the target
 address the dCDN should redirect a client to when falling back to the
 uCDN.  The fallback target address is represented as an Endpoint
 object as defined in Section 4.3.3 of [RFC8006].
 In DNS redirection, a CNAME record is used as the fallback target
 address.
 In HTTP redirection, a hostname is used as the fallback target
 address.
 When using HTTP redirect to route a client request back to the uCDN,
 it is the dCDN's 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/or the uCDN hostname from the
 redirect URL that may have been used to request the content from the
 dCDN.

3.1. Properties of Fallback Target Generic Metadata Object

 The MI.FallbackTarget generic metadata object consists of the
 following two properties:
 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 SHOULD
       NOT include a port number, and in case a port number is
       present, the dCDN MUST ignore it.
    Mandatory-to-Specify:  Yes.
 Property:  scheme
    Description:  A URI scheme to be used in the redirect response
       location construction.  When present, the dCDN MUST use this
       scheme in case of HTTP redirection to the uCDN fallback
       address.
    Type:  A URI scheme as defined in Section 3.1 of [RFC3986],
       represented as a JSON string.  The scheme MUST be either "http"
       or "https".
    Mandatory-to-Specify:  No.  In case of HTTP redirection to
       fallback, if this property is absent or empty, the dCDN
       redirecting entity MUST use the same scheme as in the request
       received by the dCDN.
 The following is an example of an MI.FallbackTarget generic metadata
 object that designates the host address the dCDN should use as
 fallback address to redirect back to the uCDN:
 {
     "generic-metadata-type": "MI.FallbackTarget",
     "generic-metadata-value":
     {
         "host": "fallback-a.service123.ucdn.example",
         "scheme": "https"
     }
 }

3.2. Usage Example

 The uCDN advertises out-of-band the fallback target address to the
 dCDN, so that the dCDN may redirect a request back to the uCDN in
 case the dCDN cannot serve it.  Using the MI, the uCDN advertises its
 hosts to the dCDN, along with their specific host metadata (see
 Section 4.1.2 of [RFC8006]).  The Fallback Target generic metadata
 object is encapsulated within the "host-metadata" property of each
 host.  The following is an example of a message flow between a uCDN
 and a dCDN.  For simplicity, we focus on the sequence of messages
 between the uCDN and dCDN, not on how they are passed.
   dCDN                                                    uCDN
     +                                                       +
     |                                                       |
 (1) | MI:  host: s123.ucdn.example.com                      |
     |      host-metadata:                                   |
     |          < metadata objects >                         |
     |          < MI.FallbackTarget                          |
     |            host: fallback-a.service123.ucdn.example > |
     |          < metadata objects >                         |
     <-------------------------------------------------------+
     |                                                       |
 (2) | FCI:  capability-type: FCI.RedirectTarget             |
     |       redirecting-hosts: s123.ucdn.example.com        |
     |       target host: us-east1.dcdn.example.com          |
     +------------------------------------------------------->
     |                                                       |
     |                                                       |
     +                                                       +
     Figure 3: Advertisement of Host Metadata with Fallback Target
 Explanation:
 (1)  The uCDN advertises a host (s123.ucdn.example.com) with the host
      metadata.  The host-metadata property contains an
      MI.FallbackTarget generic metadata object.
 (2)  The dCDN advertises its FCI objects to the uCDN, including a
      Redirect Target capability object that contains the redirect
      target address (us-east1.dcdn.example.com) specified for that
      uCDN host.
 The following is a generic sequence of redirection using the
 configurations that were advertised in Figure 3.  In this case, the
 dCDN redirects back to the uCDN fallback target address.
 End User              dCDN            uCDN fallback          uCDN RR
     +                   +                   +                   +
     |                   |                   |                   |
 (1) | Request sent s123.ucdn.example.com    |                   |
     +-------------------+-------------------+------------------->
     |                   |                   |                   |
 (2) | Redirect to us-east1.dcdn.example.com |                   |
     <-------------------+-------------------+-------------------+
     |                   |                   |                   |
 (3) | Request us-east1.dcdn.example.com     |                   |
     +------------------->                   |                   |
     |                   |                   |                   |
 (4) | Redirect back to fallback-a.service123.ucdn.example       |
     <-------------------+                   |                   |
     |                   |                   |                   |
 (5) | Request fallback-a.service123.ucdn.example                |
     +--------------------------------------->                   |
     |                   |                   |                   |
 (6) | Response          |                   |                   |
     <-------------------+-------------------+                   |
     |                   |                   |                   |
     +                   +                   +                   +
                Figure 4: Redirection to Fallback Target
 Explanation:
 (1)  The End User sends a request (DNS or HTTP) to the uCDN Request
      Router (RR).
 (2)  Using the previously advertised Redirect Target, the uCDN
      redirects the request to the dCDN.
 (3)  The End User sends a request to the dCDN.
 (4)  The dCDN cannot handle the request and therefore redirects it
      back to the uCDN fallback target address.
 (5)  The End User sends the request to the uCDN fallback target
      address.
 (6)  The uCDN either sends a response or reroutes it, for example, to
      a uCDN surrogate.

3.3. uCDN Addressing Considerations

 When advertising fallback addresses to the dCDN, the uCDN SHOULD
 consider the failure use cases that may lead the dCDN to route
 requests to uCDN fallback.  In extreme dCDN network failures or under
 denial-of-service (DoS) attacks, requests coming from a large segment
 or multiple segments of the dCDN may be routed back to the uCDN.  The
 uCDN SHOULD therefore design its fallback addressing scheme and its
 available resources accordingly.  A favorable approach would be for
 the uCDN to use a different fallback target address for each uCDN
 host, enabling it to load balance the requests using the same methods
 as it would for its original hosts.  See Sections 4.1.2 and 4.1.3 of
 [RFC8006] for a detailed description of how to use GenericMetadata
 objects within the HostMatch object advertised in the HostIndex of
 the uCDN.

4. IANA Considerations

4.1. CDNI Payload Types

 IANA has registered the following CDNI Payload Types in the "CDNI
 Payload Types" registry defined in [RFC7736]:
                +====================+===============+
                | Payload Type       | Specification |
                +====================+===============+
                | FCI.RedirectTarget | RFC 8804      |
                +--------------------+---------------+
                | MI.FallbackTarget  | RFC 8804      |
                +--------------------+---------------+
                               Table 1

4.1.1. CDNI FCI RedirectTarget Payload Type

 Purpose:  The purpose of this payload type is to distinguish FCI
    advertisement objects for redirect target.
 Interface:  FCI
 Encoding:  See Section 2.3.

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 3.1.

5. Security Considerations

 This specification defines extensions to the CDNI Metadata Interface
 (MI) and the Footprint & Capabilities Advertisement interface (FCI).
 As such, it is subject to the security and privacy considerations
 defined in Section 8 of [RFC8006] and in Section 7 of [RFC8008],
 respectively.

5.1. Confidentiality and Privacy

 The Redirect Target capability object potentially reveals information
 about the internal structure of the dCDN network.  A third party
 could intercept the FCI transactions and use the information to
 attack the dCDN.  The same is also true for the Fallback Target
 generic metadata object, as it may reveal information about the
 internal structure of the uCDN, exposing it to external exploits.
 Implementations of the FCI and MI MUST therefore use strong
 authentication and encryption and strictly follow the directions for
 securing the interface as defined for the Metadata Interface in
 Section 8.3 of [RFC8006].

6. References

6.1. 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>.
 [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>.
 [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>.
 [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>.
 [RFC7975]  Niven-Jenkins, B., Ed. and R. van Brandenburg, Ed.,
            "Request Routing Redirection Interface for Content
            Delivery Network (CDN) Interconnection", RFC 7975,
            DOI 10.17487/RFC7975, October 2016,
            <https://www.rfc-editor.org/info/rfc7975>.
 [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>.
 [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
            2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
            May 2017, <https://www.rfc-editor.org/info/rfc8174>.

6.2. Informative References

 [OC-RR]    Finkelman, O., Ed., Hofmann, J., Klein, E., Mishra, S.,
            Ma, K., Sahar, D., and B. Zurat, "Open Cache Request
            Routing Functional Specification", Version 1.1, November
            2016, <https://www.streamingvideoalliance.org/books/open-
            cache-request-routing-functional-specification/>.
 [OCWG]     Streaming Video Alliance, "Open Caching",
            <https://www.streamingvideoalliance.org/technical-groups/
            open-caching/>.
 [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>.
 [RFC7871]  Contavalli, C., van der Gaast, W., Lawrence, D., and W.
            Kumari, "Client Subnet in DNS Queries", RFC 7871,
            DOI 10.17487/RFC7871, May 2016,
            <https://www.rfc-editor.org/info/rfc7871>.
 [SVA]      "Streaming Video Alliance",
            <https://www.streamingvideoalliance.org>.

Acknowledgements

 The authors thank Nir B. Sopher for reality checks against production
 use cases; his contribution is significant to this document.  The
 authors also thank Ben Niven-Jenkins for his review and feedback and
 Kevin J. Ma for his guidance throughout the development of this
 document, including his regular reviews.

Authors' Addresses

 Ori Finkelman
 Qwilt
 6, Ha'harash
 Hod HaSharon 4524079
 Israel
 Email: ori.finkelman.ietf@gmail.com
 Sanjay Mishra
 Verizon
 13100 Columbia Pike
 Silver Spring, MD 20904
 United States of America
 Email: sanjay.mishra@verizon.com
/home/gen.uk/domains/wiki.gen.uk/public_html/data/pages/rfc/rfc8804.txt · Last modified: 2020/09/23 18:31 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki