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Versions: (draft-seedorf-cdni-request-routing-alto) 00 01 02 03 04 05 06 07

CDNI                                                          J. Seedorf
Internet-Draft                 HFT Stuttgart - Univ. of Applied Sciences
Intended status: Standards Track                                 Y. Yang
Expires: February 15, 2020                                   Tongji/Yale
                                                                   K. Ma
                                                                Ericsson
                                                             J. Peterson
                                                                 Neustar
                                                                  X. Lin
                                                                J. Zhang
                                                                  Tongji
                                                         August 14, 2019


 Content Delivery Network Interconnection (CDNI) Request Routing: CDNI
          Footprint and Capabilities Advertisement using ALTO
              draft-ietf-alto-cdni-request-routing-alto-07

Abstract

   The Content Delivery Networks Interconnection (CDNI) framework
   [RFC6707] defines a set of protocols to interconnect CDNs, to achieve
   multiple goals such as extending the reach of a given CDN to areas
   that are not covered by that particular CDN.  One component that is
   needed to achieve the goal of CDNI described in [RFC7336] is the CDNI
   Request Routing Footprint & Capabilities Advertisement interface
   (FCI).  [RFC8008] defines precisely the semantics of FCI and provides
   guidelines on the FCI protocol, but the exact protocol is explicitly
   outside the scope of that document.  In this document, we follow the
   guidelines to define an FCI protocol using the Application-Layer
   Traffic Optimization (ALTO) protocol.

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 February 15, 2020.



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Copyright Notice

   Copyright (c) 2019 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Semantics of FCI Advertisement  . . . . . . . . . . . . .   5
     2.2.  ALTO Background and Benefits  . . . . . . . . . . . . . .   6
   3.  CDNI FCI Service  . . . . . . . . . . . . . . . . . . . . . .   8
     3.1.  Media Type  . . . . . . . . . . . . . . . . . . . . . . .   8
     3.2.  HTTP Method . . . . . . . . . . . . . . . . . . . . . . .   8
     3.3.  Accept Input Parameters . . . . . . . . . . . . . . . . .   9
     3.4.  Capabilities  . . . . . . . . . . . . . . . . . . . . . .   9
     3.5.  Uses  . . . . . . . . . . . . . . . . . . . . . . . . . .   9
     3.6.  Response  . . . . . . . . . . . . . . . . . . . . . . . .   9
     3.7.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  11
       3.7.1.  IRD Example . . . . . . . . . . . . . . . . . . . . .  11
       3.7.2.  Basic Example . . . . . . . . . . . . . . . . . . . .  14
       3.7.3.  Incremental Updates Example . . . . . . . . . . . . .  15
   4.  CDNI FCI Service using ALTO Network Map . . . . . . . . . . .  17
     4.1.  Network Map Footprint Type: altopid . . . . . . . . . . .  17
     4.2.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  17
       4.2.1.  IRD Example . . . . . . . . . . . . . . . . . . . . .  17
       4.2.2.  ALTO Network Map for CDNI FCI Footprints Example  . .  17
       4.2.3.  ALTO PID Footprints in CDNI FCI . . . . . . . . . . .  18
       4.2.4.  Incremental Updates Example . . . . . . . . . . . . .  19
   5.  Filtered CDNI FCI using Capabilities  . . . . . . . . . . . .  21
     5.1.  Media Type  . . . . . . . . . . . . . . . . . . . . . . .  21
     5.2.  HTTP Method . . . . . . . . . . . . . . . . . . . . . . .  21
     5.3.  Accept Input Parameters . . . . . . . . . . . . . . . . .  21
     5.4.  Capabilities  . . . . . . . . . . . . . . . . . . . . . .  22
     5.5.  Uses  . . . . . . . . . . . . . . . . . . . . . . . . . .  22
     5.6.  Response  . . . . . . . . . . . . . . . . . . . . . . . .  22
     5.7.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  23
       5.7.1.  IRD Example . . . . . . . . . . . . . . . . . . . . .  23



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       5.7.2.  Basic Example . . . . . . . . . . . . . . . . . . . .  23
       5.7.3.  Incremental Updates Example . . . . . . . . . . . . .  25
   6.  Query Footprint Properties using ALTO Property Map Service  .  26
     6.1.  Representing Footprint Objects as Unified Property Map
           Entities  . . . . . . . . . . . . . . . . . . . . . . . .  27
       6.1.1.  ASN Domain  . . . . . . . . . . . . . . . . . . . . .  27
       6.1.2.  COUNTRYCODE Domain  . . . . . . . . . . . . . . . . .  28
     6.2.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  28
       6.2.1.  IRD Example . . . . . . . . . . . . . . . . . . . . .  28
       6.2.2.  Property Map Example  . . . . . . . . . . . . . . . .  28
       6.2.3.  Filtered Property Map Example . . . . . . . . . . . .  30
       6.2.4.  Incremental Updates Example . . . . . . . . . . . . .  31
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  33
     7.1.  CDNI Metadata Footprint Type Registry . . . . . . . . . .  33
     7.2.  ALTO Entity Domain Type Registry  . . . . . . . . . . . .  33
     7.3.  ALTO Entity Property Type Registry  . . . . . . . . . . .  33
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  34
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  35
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  35
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  35
     10.2.  Informative References . . . . . . . . . . . . . . . . .  36
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  36

1.  Introduction

   The ability to interconnect multiple content delivery networks (CDNs)
   has many benefits, including increased coverage, capability, and
   reliability.  The Content Delivery Networks Interconnection (CDNI)
   framework [RFC6707] defines four interfaces to achieve
   interconnection of CDNs: (1) the CDNI Request Routing Interface; (2)
   the CDNI Metadata Interface; (3) the CDNI Logging Interface; and (4)
   the CDNI Control Interface.

   Among the four interfaces, the CDNI Request Routing Interface
   provides key functions, as specified in [RFC6707]: "The CDNI Request
   Routing interface enables a Request Routing function in an Upstream
   CDN to query a Request Routing function in a Downstream CDN to
   determine if the Downstream CDN is able (and willing) to accept the
   delegated Content Request.  It also allows the Downstream CDN to
   control what should be returned to the User Agent in the redirection
   message by the upstream Request Routing function."  On a high level,
   the scope of the CDNI Request Routing Interface, therefore, contains
   two main tasks: (1) determining if the downstream CDN (dCDN) is
   willing to accept a delegated content request; (2) redirecting the
   content request coming from an upstream CDN (uCDN) to the proper
   entry point or entity in the downstream CDN.





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   Correspondingly, the request routing interface is broadly divided
   into two functionalities: (1) CDNI Footprint & Capabilities
   Advertisement interface (FCI); (2) CDNI Request Routing Redirection
   interface (RI).  Since this document focuses on the first
   functionality, CDNI FCI, we will describe it in a more detailed way.
   CDNI FCI is an advertisement from a dCDN to a uCDN (push) or a query
   from a uCDN to a dCDN (pull) so that the uCDN knows whether it can
   redirect a particular user request to that dCDN.

   A key component in defining CDNI FCI is defining objects describing
   the footprints and capabilities of a dCDN.  Such objects are already
   in [RFC8008].  A protocol to transport and update such objects
   between a uCDN and a dCDN, however, is not defined.  Hence, the scope
   of this document is to define such a protocol by introducing a new
   Application-Layer Traffic Optimization (ALTO) [RFC7285] service
   called "CDNI FCI Map Service".

   There are multiple benefits in using ALTO as a transport protocol, as
   we discuss in Section 2.2.

   The rest of this document is organized as follows.  Section 2
   provides non-normative background on both CDNI FCI and ALTO.
   Section 3 introduces the most basic service, called CDNI FCI Map, to
   realize CDNI FCI using ALTO.  Section 4 demonstrates a key benefit of
   using ALTO: the ability to integrate CDNI FCI with ALTO network maps.
   Such integration provides a new granularity to describe footprints.
   Section 5 builds on filtered ALTO maps to introduce filtered CDNI FCI
   maps using capabilities so that a uCDN can get footprints with given
   capabilities instead of getting the full map which can be huge.
   Section 6 further shows a benefit of using ALTO: the ability to query
   footprint properties using ALTO unified properties.  In this way, a
   uCDN can effectively fetch capabilities of some footprints in which
   it is interested.  IANA and security considerations are discussed in
   Section 7 and Section 8 respectively.

   Throughout this document, we use the terminology for CDNI defined in
   [RFC6707], [RFC8006], [RFC8008] and we use the terminology for ALTO
   defined in [RFC7285], [I-D.ietf-alto-unified-props-new].

2.  Background

   The design of CDNI FCI transport using ALTO depends on the
   understanding of both FCI semantics and ALTO.  Hence, we start with a
   review of both.







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2.1.  Semantics of FCI Advertisement

   The CDNI document on "Footprint and Capabilities Semantics" [RFC8008]
   defines the semantics of CDNI FCI, and provides guidance on what
   Footprint and Capabilities mean in a CDNI context and how a protocol
   solution should in principle look like.  The definitions in [RFC8008]
   depend on [RFC8006].  Here we briefly summarize key related points of
   [RFC8008] and [RFC8006].  For a detailed discussion, the reader is
   referred to the RFCs.

   o  Footprint and capabilities are tied together and cannot be
      interpreted independently from each other.  Hence, capabilities
      must be expressed on a per footprint basis.  [RFC8008] integrates
      footprint and capabilities with an approach of "capabilities with
      footprint restrictions".

   o  Given that a large part of Footprint and Capabilities
      Advertisement will actually happen in contractual agreements, the
      semantics of CDNI Footprint and Capabilities advertisement refers
      to answering the following question: what exactly still needs to
      be advertised by the CDNI FCI?  For instance, updates about
      temporal failures of part of a footprint can be useful information
      to convey via the CDNI request routing interface.  Such
      information would provide updates on information previously agreed
      in contracts between the participating CDNs.  In other words, the
      CDNI FCI is a means for a dCDN to provide changes/updates
      regarding a footprint and/or capabilities that it has prior agreed
      to serve in a contract with a uCDN.  Hence, server push and
      incremental encoding will be necessary techniques.

   o  Multiple types of footprints (ipv4cidr, ipv6cidr, asn and
      countrycode) are defined in [RFC8006].

   o  A "Set of IP-prefixes" can contain both full IP addresses (i.e., a
      /32 for IPv4 and a /128 for IPv6) and IP prefixes with an
      arbitrary prefix length.  There must also be support for multiple
      IP address versions, i.e., IPv4 and IPv6, in such a footprint.

   o  For all of these mandatory-to-implement footprint types,
      footprints can be viewed as constraints for delegating requests to
      a dCDN: A dCDN footprint advertisement tells the uCDN the
      limitations for delegating a request to the dCDN.  For IP prefixes
      or ASN(s), the footprint signals to the uCDN that it should
      consider the dCDN a candidate only if the IP address of the
      request routing source falls within the prefix set (or ASN,
      respectively).  The CDNI specifications do not define how a given
      uCDN determines what address ranges are in a particular ASN.
      Similarly, for country codes, a uCDN should only consider the dCDN



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      a candidate if it covers the country of the request routing
      source.  The CDNI specifications do not define how a given uCDN
      determines the country of the request routing source.  Multiple
      footprint constraints are additive, i.e., the advertisement of
      different types of footprint narrows the dCDN candidacy
      cumulatively.

   o  The following capabilities are defined as "base" capabilities;
      that is, they are required in all cases and therefore constitute
      mandatory capabilities to be supported by the CDNI FCI: (1)
      Delivery Protocol; (2) Acquisition Protocol; (3) Redirection Mode;
      (4) Capabilities related to CDNI Logging; (5) Capabilities related
      to CDNI Metadata.

2.2.  ALTO Background and Benefits

   Application-Layer Traffic Optimization (ALTO) [RFC7285] is an
   approach for guiding the resource provider selection process in
   distributed applications that can choose among several candidate
   resources providers to retrieve a given resource.  By conveying
   network layer (topology) information, an ALTO server can provide
   important information to "guide" the resource provider selection
   process in distributed applications.  Usually, it is assumed that an
   ALTO server conveys information that these applications cannot or
   have difficulty to measure themselves [RFC5693].

   Originally, ALTO was motivated by optimizing cross-ISP traffic
   generated by P2P applications [RFC5693].  Recently, however, ALTO is
   also being considered for improving the request routing in CDNs
   [I-D.jenkins-alto-cdn-use-cases].  The CDNI problem statement
   explicitly mentions ALTO as a candidate protocol for "actual
   algorithms for selection of CDN or Surrogate by Request-Routing
   systems" [RFC6707].

   The following reasons make ALTO a suitable candidate protocol for
   downstream CDN selection as part of CDNI request routing and in
   particular for an FCI protocol:

   o  ALTO is a protocol specifically designed to improve application
      layer traffic (and application layer connections among hosts on
      the Internet) by providing additional information to applications
      that these applications could not easily retrieve themselves.  For
      CDNI, this is exactly the case: a uCDN wants to improve
      application layer CDN request routing by using dedicated
      information (provided by a dCDN) that the uCDN could not easily
      obtain otherwise.  ALTO can help a uCDN to select a proper dCDN by
      first providing dCDNs' capabilities as well as footprints (see




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      Section 3) and then providing costs of surrogates in a dCDN by
      ALTO cost maps.

   o  The semantics of an ALTO network map is an exact match for the
      needed information to convey a footprint by a downstream CDN, in
      particular if such a footprint is being expressed by IP-prefix
      ranges.  Please see Section 4.

   o  Security: Identifications between uCDNs and dCDNs are extremely
      important.  ALTO maps can be signed and hence provide inherent
      integrity protection.  Please see Section 8.

   o  RESTful-Design: The ALTO protocol has undergone extensive
      revisions in order to provide a RESTful design regarding the
      client-server interaction specified by the protocol.  A CDNI FCI
      interface based on ALTO would inherit this RESTful design.  Please
      see Section 3.

   o  Error-handling: The ALTO protocol has undergone extensive
      revisions in order to provide sophisticated error-handling, in
      particular regarding unexpected cases.  A CDNI FCI interface based
      on ALTO would inherit this thought-through and mature error-
      handling.  Please see Section 5.

   o  Filtered map service: The ALTO map filtering service would allow a
      uCDN to query only for parts of an ALTO map.  For example,
      filtered unified property map service can enable a uCDN to query
      properties of a part of footprints in an effective way (see
      Section 6).

   o  Server-initiated Notifications and Incremental Updates: When the
      footprint or the capabilities of a downstream CDN change (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 requests 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.  The newest design of ALTO supports server
      pushed incremental updates [I-D.ietf-alto-incr-update-sse].

   o  Content Availability on Hosts: A dCDN might want to express CDN
      capabilities in terms of certain content types (e.g., codecs/
      formats, or content from certain content providers).  The new



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      endpoint property for ALTO would enable a dCDN to make such
      information available 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 downstream
      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.  ALTO Path Vector Extension [I-D.ietf-alto-path-vector]
      is designed to allow ALTO clients to query information such as
      capacity regions for a given set of flows.

3.  CDNI FCI Service

   The ALTO protocol is based on an ALTO Information Service Framework
   which consists of several services, where all ALTO services are
   "provided through a common transport protocol, messaging structure
   and encoding, and transaction model" [RFC7285].  The ALTO protocol
   specification [RFC7285] defines several such services, e.g., the ALTO
   map service.

   This document defines a new ALTO Service called "CDNI FCI Service"
   which conveys JSON objects of media type "application/alto-
   cdnifci+json".  These JSON objects are used to transport
   BaseAdvertisementObject objects defined in [RFC8008]; this document
   specifies how to transport such BaseAdvertisementObject objects via
   the ALTO protocol with the ALTO "CDNI FCI Service".  Similar to other
   ALTO services, this document defines the ALTO information resource
   for the "CDNI FCI Service" as follows.

3.1.  Media Type

   The media type of the CDNI FCI resource is "application/alto-
   cdnifci+json".

3.2.  HTTP Method

   A CDNI FCI resource is requested using the HTTP GET method.






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3.3.  Accept Input Parameters

   None.

3.4.  Capabilities

   None.

3.5.  Uses

   The "uses" field SHOULD NOT appear unless the CDNI FCI resource
   depends on some ALTO information resources.  If the CDNI FCI resource
   has some dependent resources, the resource IDs of its dependent
   resources MUST be included into the "uses" field.  This document only
   defines one potential dependent resource for the CDNI FCI resource.
   See Section 4 for details of when and how to use it.  The future
   documents may extend the CDNI FCI resource and allow other dependent
   resources.

3.6.  Response

   The "meta" field of a CDNI FCI response MUST include the "vtag" field
   defined in Section 10.3 of [RFC7285].  This field provides the
   version of the retrieved CDNI FCI map.

   If a CDNI FCI response depends on an ALTO information resource, it
   MUST include the "dependent-vtags" field, whose value is an array to
   indicate the version tags of the resources used, where each resource
   is specified in "uses" of its IRD entry.

   The data component of an ALTO CDNI FCI response is named "cdni-fci",
   which is a JSON object of type CDNIFCIData:

       object {
           CDNIFCIData cdni-fci;
       } InfoResourceCDNIFCI : ResponseEntityBase;

       object {
           BaseAdvertisementObject capabilities<1..*>;
       } CDNIFCIData;

   Specifically, a CDNIFCIData object is a JSON object that includes
   only one property named "capabilities", whose value is an array of
   BaseAdvertisementObject objects.

   The syntax and semantics of BaseAdvertisementObject are well defined
   in Section 5.1 of [RFC8008].  A BaseAdvertisementObject object
   includes multiple properties, including capability-type, capability-



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   value and footprints, where footprints are defined in Section 4.2.2.2
   of [RFC8006].

   To be self-contained, we give a non-normative specification of
   BaseAdvertisementObject below.  As mentioned above, the normative
   specification of BaseAdvertisementObject is in [RFC8008]

       object {
           JSONString capability-type;
           JSONValue capability-value;
           Footprint footprints<0..*>;
       } BaseAdvertisementObject;

       object {
           JSONString footprint-type;
           JSONString footprint-value<1..*>;
       } Footprint;

   For each BaseAdvertisementObject, the ALTO client MUST interpret
   footprints appearing multiple times as if they appeared only once.
   If footprints in a BaseAdvertisementObject is null or empty or not
   appearing, the ALTO client MUST understand that the capabilities in
   this BaseAdvertisementObject have the "global" coverage.

   Note: Further optimization of BaseAdvertisement objects to
   effectively provide the advertisement of capabilities with footprint
   restrictions is certainly possible.  For example, these two examples
   below both describe that the dCDN can provide capabilities
   ["http/1.1", "https/1.1"] for the same footprints.  However, the
   latter one is smaller in its size.

   EXAMPLE 1
       {
         "meta" : {...},
         "cdni-fci": {
           "capabilities": [
             {
               "capability-type": "FCI.DeliveryProtocol",
               "capability-value": {
                 "delivery-protocols": [
                   "http/1.1"
                 ]
               },
               "footprints": [
                 <Footprint objects>
               ]
             },
             {



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               "capability-type": "FCI.DeliveryProtocol",
               "capability-value": {
                 "delivery-protocols": [
                   "https/1.1"
                 ]
               },
               "footprints": [
                 <Footprint objects>
               ]
             }
           ]
         }
       }

   EXAMPLE 2
       {
         "meta" : {...},
         "cdni-fci": {
           "capabilities": [
             {
               "capability-type": "FCI.DeliveryProtocol",
               "capability-value": {
                 "delivery-protocols": [
                   "https/1.1",
                   "http/1.1"
                 ]
               },
               "footprints": [
                 <Footprint objects>
               ]
             }
           ]
         }
       }

   Since such optimizations are not required for the basic
   interconnection of CDNs, the specifics of such mechanisms are outside
   the scope of this document.

3.7.  Examples

3.7.1.  IRD Example

   Below is the information resource directory (IRD) of a simple,
   example ALTO server.  The server provides both base ALTO information
   resources (e.g., network maps) and CDNI FCI related information
   resources (e.g., CDNI FCI resource), demonstrating a single,
   integrated environment.



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   Specifically, the IRD announces two network maps, one CDNI FCI
   resource without dependency, one CDNI FCI resource depending on a
   network map, one filtered CDNI FCI resource to be defined in
   Section 5, one unified property map including "cdni-fci-capabilities"
   as its entity property, one filtered unified property map including
   "cdni-fci-capabilities" and "pid" as its entity properties, and two
   update stream services (one for updating CDNI FCI resources, and the
   other for updating property maps).

    GET /directory HTTP/1.1
    Host: alto.example.com
    Accept: application/alto-directory+json,application/alto-error+json

    {
      "meta" : { ... },
      "resources": {
        "my-default-network-map": {
          "uri" : "http://alto.example.com/networkmap",
          "media-type" : "application/alto-networkmap+json"
        },
        "my-eu-netmap" : {
          "uri" : "http://alto.example.com/myeunetmap",
          "media-type" : "application/alto-networkmap+json"
        },
        "my-default-cdnifci": {
          "uri" : "http://alto.example.com/cdnifci",
          "media-type": "application/alto-cdnifci+json"
        },
        "my-filtered-cdnifci" : {
          "uri" : "http://alto.example.com/cdnifci/filtered",
          "media-type" : "application/alto-cdnifci+json",
          "accepts" : "application/alto-cdnifcifilter+json",
          "uses" : [ "my-default-cdnifci" ]
        },
        "my-cdnifci-with-pid-footprints": {
          "uri" : "http://alto.example.com/networkcdnifci",
          "media-type" : "application/alto-cdnifci+json",
          "uses" : [ "my-eu-netmap" ]
        },
        "cdnifci-property-map" : {
          "uri" : "http://alto.example.com/propmap/full/cdnifci",
          "media-type" : "application/alto-propmap+json",
          "uses": [ "my-default-cdni" ],
          "capabilities" : {
            "mappings": {
              "ipv4": [ "my-default-cdni.cdni-fci-capabilities" ],
              "ipv6": [ "my-default-cdni.cdni-fci-capabilities" ],
              "countrycode": [



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                "my-default-cdni.cdni-fci-capabilities" ],
              "asn": [ "my-default-cdni.cdni-fci-capabilities" ],
            }
          }
        },
        "filtered-cdnifci-property-map" : {
          "uri" : "http://alto.example.com/propmap/lookup/cdnifci-pid",
          "media-type" : "application/alto-propmap+json",
          "accepts" : "application/alto-propmapparams+json",
          "uses": [ "my-default-cdni", "my-default-network-map" ],
          "capabilities" : {
            "mappings": {
              "ipv4": [ "my-default-cdni.cdni-fci-capabilities",
                        "my-default-network-map.pid" ],
              "ipv6": [ "my-default-cdni.cdni-fci-capabilities",
                        "my-default-network-map.pid" ],
              "countrycode": [
                "my-default-cdni.cdni-fci-capabilities" ],
              "asn": [ "my-default-cdni.cdni-fci-capabilities" ],
            }
          }
        },
        "update-my-cdni-fci" : {
          "uri": "http:///alto.example.com/updates/cdnifci",
          "media-type" : "text/event-stream",
          "accepts" : "application/alto-updatestreamparams+json",
          "uses" : [
            "my-default-network-map",
            "my-eu-netmap",
            "my-default-cdnifci",
            "my-filtered-cdnifci"
            "my-cdnifci-with-pid-footprints"
          ],
          "capabilities" : {
            "incremental-change-media-types" : {
             "my-default-network-map" : "application/json-patch+json",
             "my-eu-netmap" : "application/json-patch+json",
             "my-default-cdnifci" :
             "application/merge-patch+json,application/json-patch+json",
             "my-filtered-cdnifci" :
             "application/merge-patch+jso,application/json-patch+json",
             "my-cdnifci-with-pid-footprints" :
             "application/merge-patch+json,application/json-patch+json"
            }
          }
        },
        "update-my-props": {
          "uri" : "http://alto.example.com/updates/properties",



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          "media-type" : "text/event-stream",
          "uses" : [
            "cdnifci-property-map",
            "filtered-cdnifci-property-map"
          ],
          "capabilities" : {
            "incremental-change-media-types": {
             "cdnifci-property-map" :
             "application/merge-patch+json,application/json-patch+json",
             "filtered-cdnifci-property-map":
             "application/merge-patch+json,application/json-patch+json"
            }
          }
        }
      }
    }

3.7.2.  Basic Example

   In this example, we demonstrate a simple CDNI FCI resource; this
   resource does not depend on other resources.  There are three
   BaseAdvertisementObjects in this map and these objects' capabilities
   are http/1.1 delivery protocol, [http/1.1, https/1.1] delivery
   protocol and https/1.1 acquisition protocol respectively.

     GET /cdnifci HTTP/1.1
     Host: alto.example.com
     Accept: application/alto-cdnifci+json,
             application/alto-error+json

     HTTP/1.1 200 OK
     Content-Length: XXX
     Content-Type: application/alto-cdnifci+json
     {
       "meta" : {
         "vtag": {
           "resource-id": "my-default-cdnifci",
           "tag": "da65eca2eb7a10ce8b059740b0b2e3f8eb1d4785"
         }
       },
       "cdni-fci": {
         "capabilities": [
           {
             "capability-type": "FCI.DeliveryProtocol",
             "capability-value": {
               "delivery-protocols": [
                 "http/1.1"
               ]



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             },
             "footprints": [
               <Footprint objects>
             ]
           },
           {
             "capability-type": "FCI.DeliveryProtocol",
             "capability-value": {
               "delivery-protocols": [
                 "https/1.1",
                 "http/1.1"
               ]
             },
             "footprints": [
               <Footprint objects>
             ]
           },
           {
             "capability-type": "FCI.AcquisitionProtocol",
             "capability-value": {
               "acquisition-protocols": [
                 "https/1.1"
               ]
             },
             "footprints": [
               <Footprint objects>
             ]
           }
         ]
       }
     }

3.7.3.  Incremental Updates Example

   A benefit of using ALTO to provide CDNI FCI maps is that such maps
   can be updated using ALTO incremental updates.  Below is an example
   that also shows the benefit of having both JSON merge patch and JSON
   patch to encode updates.

   At first, an ALTO client requests updates for "my-default-cdnifci",
   and the ALTO server returns the "control-uri" followed by the full
   CDNI FCI response.  Then when there is a change in the delivery-
   protocols in that `http/2` is removed (from http/1.1 and http/2 to
   only http/1.1) due to maintenance of the http/2 clusters, the ALTO
   server uses JSON merge patch to encode the change and pushes the
   change to the ALTO client.  Later on, the ALTO server notifies the
   ALTO client that "ipv4:192.0.2.0/24" is added into the footprint for




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   delivery-protocol http/1.1 by sending the change encoded by JSON
   patch to the ALTO client.

     POST /updates/cdnifci HTTP/1.1
     Host: alto.example.com
     Accept: text/event-stream,application/alto-error+json
     Content-Type: application/alto-updatestreamparams+json
     Content-Length: ###

     { "add": {
         "my-cdnifci-stream": {
             "resource-id": "my-default-cdnifci"
         }
     }

     HTTP/1.1 200 OK
     Connection: keep-alive
     Content-Type: text/event-stream

     event: application/alto-updatestreamcontrol+json
     data: {"control-uri":
     data: "http://alto.example.com/updates/streams/3141592653589"}

     event: application/alto-cdnifci+json,my-default-cdnifci
     data: { ... full CDNI FCI map ... }

     event: application/merge-patch+json,my-default-cdnifci
     data: {
     data:   "meta": {
     data:     "vtag": {
     data:       "tag": "dasdfa10ce8b059740bddsfasd8eb1d47853716"
     data:     }
     data:   },
     data:   "cdni-fci": {
     data:     "capabilities": [
     data:       {
     data:         "capability-type": "FCI.DeliveryProtocol",
     data:         "capability-value": {
     data:           "delivery-protocols": [
     data:             "http/1.1"
     data:           ]
     data:         },
     data:         "footprints": [
     data:           <Footprint objects in only http/1.1>
     data:         ]
     data:       }
     data:     ]
     data:   }



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     data: }

     event: application/json-patch+json,my-default-cdnifci
     data: [
     data:   {
     data:     "op": "replace",
     data:     "path": "/meta/vtag/tag",
     data:     "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
     data:   },
     data:   { "op": "add",
     data:     "path": "/cdni-fci/capabilities/0/footprints/-",
     data:     "value": "ipv4:192.0.2.0/24"
     data:   }
     data: ]

4.  CDNI FCI Service using ALTO Network Map

4.1.  Network Map Footprint Type: altopid

   The ALTO protocol defines a concept called PID to represent a group
   of IPv4 or IPv6 addresses which can be applied the same management
   policy.  The PID is an alternative to the pre-defined CDNI footprint
   types (i.e., ipv4cidr, ipv6cidr, asn, and countrycode).

   Specifically, a CDNI FCI resource can depend on an ALTO network map
   resource and use a new CDNI Footprint Type called "altopid" to
   compress its CDNI Footprint Payload.

   "altopid" footprint type indicates that the corresponding footprint
   value is a list of PIDNames as defined in [RFC7285].  These PIDNames
   are references of PIDs in a network map resource.  Hence a CDNI FCI
   with "altopid" footprints depends on a network map.  For such a CDNI
   FCI map, the resource id of its dependent network map MUST be
   included in the "uses" field of its IRD entry, and the "dependent-
   vtag" field with a reference to this network map MUST be included in
   its response (see the example in Section 4.2.3).

4.2.  Examples

4.2.1.  IRD Example

   We use the same IRD example given in Section 3.7.1.

4.2.2.  ALTO Network Map for CDNI FCI Footprints Example

   Below is an example network map whose resource id is "my-eu-netmap",
   and this map is referenced by the CDNI FCI example in Section 4.2.3.




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    GET /networkmap HTTP/1.1
    Host: http://alto.example.com/myeunetmap
    Accept: application/alto-networkmap+json,application/alto-error+json

    HTTP/1.1 200 OK
    Content-Length: XXX
    Content-Type: application/alto-networkmap+json

    {
      "meta" : {
        "vtag": [
          {"resource-id": "my-eu-netmap",
           "tag": "3ee2cb7e8d63d9fab71b9b34cbf764436315542e"
          }
        ]
      },
      "network-map" : {
        "south-france" : {
          "ipv4" : [ "192.0.2.0/24", "198.51.100.0/25" ]
        },
        "germany" : {
          "ipv4" : [ "192.0.3.0/24"]
        }
      }
    }

4.2.3.  ALTO PID Footprints in CDNI FCI

   In this example, we show a CDNI FCI resource that depends on a
   network map described in Section 4.2.2.

    GET /networkcdnifci HTTP/1.1
    Host: alto.example.com
    Accept: application/alto-cdnifci+json,application/alto-error+json

















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    HTTP/1.1 200 OK
    Content-Length: 618
    Content-Type: application/alto-cdnifci+json

    {
      "meta" : {
        "dependent-vtags" : [
          {
            "resource-id": "my-eu-netmap",
            "tag": "3ee2cb7e8d63d9fab71b9b34cbf764436315542e"
          }
        ]
      },
      "cdni-fci": {
        "capabilities": [
          { "capability-type": "FCI.DeliveryProtocol",
            "capability-value": [
              "http/1.1"
            ]
          },
          { "capability-type": "FCI.DeliveryProtocol",
            "capability-value": [
              "https/1.1"
            ],
            "footprints": [
              { "footprint-type": "altopid",
                "footprint-value": [
                  "germany",
                  "south-france"
                ]
              }
            ]
          }
        ]
      }
    }

4.2.4.  Incremental Updates Example

   In this example, the ALTO client is interested in changes of "my-
   cdnifci-with-pid-footprints".  Considering two changes, the first one
   is to change footprints of http/1.1 Delivery Protocol capability, and
   the second one is to remove "south-france" from the footprints of
   https/1.1 delivery protocol capability.

     POST /updates/cdnifci HTTP/1.1
     Host: alto.example.com
     Accept: text/event-stream,application/alto-error+json



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     Content-Type: application/alto-updatestreamparams+json
     Content-Length: ###

     { "add": {
         "my-network-map-cdnifci-stream": {
             "resource-id": "my-cdnifci-with-pid-footprints"
         }
     }

     HTTP/1.1 200 OK
     Connection: keep-alive
     Content-Type: text/event-stream

     event: application/alto-updatestreamcontrol+json
     data: {"control-uri":
     data: "http://alto.example.com/updates/streams/3141592653590"}

     event: application/alto-cdnifci+json,my-fci-stream
     data: { ... full CDNI FCI resource ... }

     event: application/merge-patch+json,my-fci-stream
     data: {
     data:   "meta": {
     data:     "dependent-vtags" : [
     data:      {
     data:        "resource-id": "my-eu-netmap",
     data:        "tag": "3ee2cb7e8d63d9fab71b9b34cbf764436315542e"
     data:      }
     data:     ],
     data:     "vtag": {
     data:       "tag": "dasdfa10ce8b059740bddsfasd8eb1d47853716"
     data:     }
     data:   },
     data:   {
     data:     "capability-type": "FCI.DeliveryProtocol",
     data:     "capability-value": {
     data:       "delivery-protocols": [
     data:         "http/1.1"
     data:       ]
     data:     },
     data:     "footprints": [
     data:       <All footprint objects in http/1.1>
     data:     ]
     data:   }
     data: }

     event: application/json-patch+json,my-fci-stream
     data: [



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     data:   {
     data:     "op": "replace",
     data:     "path": "/meta/vtag/tag",
     data:     "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
     data:   },
     data:   { "op": "remove",
     data:     "path": "/cdni-fci/capabilities/2/footprints/0/
     data:       footprint-value/1",
     data:   }
     data: ]

5.  Filtered CDNI FCI using Capabilities

   Section 3 and Section 4 describe CDNI FCI Service which can be used
   to enable a uCDN to get capabilities with footprints constrains from
   dCDNs.  However, always getting full CDNI FCI resources from dCDNs is
   very inefficient, hence we introduce a new service named "Filtered
   CDNI FCI Service" to allow a client to filter a CDNI FCI resource
   using a client-given set of capabilities.  For each entry of the CDNI
   FCI response, only if the entry contains at least one of the client-
   given capabilities will it be returned to the client.  The
   relationship between a filtered CDNI FCI resource and a CDNI FCI
   resource is similar to the relationship between a filtered network/
   cost map and a network/cost map.

5.1.  Media Type

   A filtered CDNI FCI resource uses the same media type defined for the
   CDNI FCI resource in Section 3.1.

5.2.  HTTP Method

   A filtered CDNI FCI resource is requested using the HTTP POST method.

5.3.  Accept Input Parameters

   The input parameters for a filtered CDNI FCI resource are supplied in
   the entity body of the POST request.  This document specifies the
   input parameters with a data format indicated by the media type
   "application/alto-cdnifcifilter+json" which is a JSON object of type
   ReqFilteredCDNIFCI, where:










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      object {
          JSONString capability-type;
          JSONValue capability-value;
      } CDNIFCICapability;

      object {
          [CDNIFCICapability cdni-fci-capabilities<0..*>;]
      } ReqFilteredCDNIFCI;

   with fields:

   capability-type:  The same as Base Advertisement Object's capability-
      type defined in Section 5.1 of [RFC8008].

   capability-value:  The same as Base Advertisement Object's
      capability-value defined in Section 5.1 of [RFC8008].

   cdni-fci-capabilities:  A list of CDNI FCI capabilities defined in
      Section 5.1 of [RFC8008] for which footprints are to be returned.
      If a list is empty or not appearing, the ALTO server MUST
      interpret it as a request for the full CDNI FCI resource.  The
      ALTO server MUST interpret entries appearing in a list multiple
      times as if they appeared only once.  If the ALTO server does not
      define any footprints for a CDNI capability, it MUST omit this
      capability from the response.

5.4.  Capabilities

   None.

5.5.  Uses

   The resource ID of the CDNI FCI resource based on which the filtering
   is performed.

5.6.  Response

   The response MUST indicate an error, using ALTO protocol error
   handling specified in Section 8.5 of the ALTO protocol [RFC7285], if
   the request is invalid.

   Specifically, a filtered CDNI FCI request is invalid if:

   o  the value of "capability-type" is null;

   o  the value of "capability-value" is null;





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   o  the value of "capability-value" is inconsistent with "capability-
      type".

   When a request is invalid, the ALTO server MUST return an
   "E_INVALID_FIELD_VALUE" error defined in Section 8.5.2 of [RFC7285],
   and the "value" field of the error message SHOULD indicate this CDNI
   FCI capability.

   The ALTO server returns a filtered CDNI FCI resource for a valid
   request.  The format of a filtered CDNI FCI resource is the same as
   an full CDNI FCI resource (See Section 3.6.)

   The returned CDNI FCI resource MUST contain only
   BaseAdvertisementObject objects whose CDNI capability object is the
   superset of one of CDNI capability object in "cdni-fci-capabilities".
   Specifically, that a CDNI capability object A is the superset of
   another CDNI capability object B means that these two CDNI capability
   objects have the same capability type and mandatory properties in
   capability value of A MUST include mandatory properties in capability
   value of B semantically.  See Section 5.7.2 for a concrete example.

   The version tag included in the "vtag" field of the response MUST
   correspond to the full CDNI FCI resource from which the filtered CDNI
   FCI resource is provided.  This ensures that a single, canonical
   version tag is used independently of any filtering that is requested
   by an ALTO client.

5.7.  Examples

5.7.1.  IRD Example

   We use the same IRD example by Section 3.7.1.

5.7.2.  Basic Example

   This example filters the full CDNI FCI resource in Section 3.7.2 by
   selecting only http/1.1 delivery protocol capability.  Only the first
   two BaseAdvertisementObjects in the full resource will be returned
   because the first object's capability is http/1.1 delivery protocol
   and the second object's capability is http/1.1 and https/1.1 delivery
   protocols which is the superset of http/1.1 delivery protocol.

     POST /cdnifci/filtered HTTP/1.1
     HOST: alto.example.com
     Content-Type: application/cdnifilter+json
     Accept: application/alto-cdnifci+json

     {



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       "cdni-fci-capabilities": [
         {
           "capability-type": "FCI.DeliveryProtocol",
           "capability-value": {
             "delivery-protocols": [
               "http/1.1"
             ]
           }
         }
       ]
     }

     HTTP/1.1 200 OK
     Content-Length: XXX
     Content-Type: application/alto-cdnifci+json
     {
       "meta" : {
         "vtag": {
           "resource-id": "my-default-cdnifci",
           "tag": "da65eca2eb7a10ce8b059740b0b2e3f8eb1d4785"
         }
       },
       "cdni-fci": {
         "capabilities": [
           {
             "capability-type": "FCI.DeliveryProtocol",
             "capability-value": {
               "delivery-protocols": [
                 "http/1.1"
               ]
             },
             "footprints": [
               <Footprint objects>
             ]
           },
           {
             "capability-type": "FCI.DeliveryProtocol",
             "capability-value": {
               "delivery-protocols": [
                 "https/1.1",
                 "http/1.1"
               ]
             },
             "footprints": [
               <Footprint objects>
             ]
           }
         ]



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       }
     }

5.7.3.  Incremental Updates Example

   In this example, the ALTO client only cares about the updates of one
   Delivery Protocol object whose value is "http/1.1".  So it adds its
   limitation of capabilities in "input" field of the POST request.

     POST /updates/cdnifci HTTP/1.1
     Host: fcialtoupdate.example.com
     Accept: text/event-stream,application/alto-error+json
     Content-Type: application/alto-updatestreamparams+json
     Content-Length: ###

     { "add": {
         "my-fci-stream": {
             "resource-id": "my-filtered-cdnifci",
             "input": {
               "cdni-fci-capabilities": [
               {
                 "capability-type": "FCI.DeliveryProtocol",
                 "capability-value": {
                   "delivery-protocols": [
                     "http/1.1"
                   ]
                 }
               }
             ]
           }
         }
       }
     }

     HTTP/1.1 200 OK
     Connection: keep-alive
     Content-Type: text/event-stream

     event: application/alto-updatestreamcontrol+json
     data: {"control-uri":
     data: "http://alto.example.com/updates/streams/3141592653590"}

     event: application/alto-cdnifci+json,my-fci-stream
     data: { ... full filtered CDNI FCI resource ... }

     event: application/merge-patch+json,my-fci-stream
     data: {
     data:   "meta": {



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     data:     "vtag": {
     data:       "tag": "dasdfa10ce8b059740bddsfasd8eb1d47853716"
     data:     }
     data:   },
     data:   {
     data:     "capability-type": "FCI.DeliveryProtocol",
     data:     "capability-value": {
     data:       "delivery-protocols": [
     data:         "http/1.1"
     data:       ]
     data:     },
     data:     "footprints": [
     data:       <All footprint objects in http/1.1>
     data:     ]
     data:   }
     data: }

     event: application/json-patch+json,my-fci-stream
     data: [
     data:   {
     data:     "op": "replace",
     data:     "path": "/meta/vtag/tag",
     data:     "value": "a10ce8b059740b0b2e3f8eb1d4785acd42231bfe"
     data:   },
     data:   { "op": "add",
     data:     "path": "/cdni-fci/capabilities/0/footprints/-",
     data:     "value": "ipv4:192.0.2.0/24"
     data:   }
     data: ]

6.  Query Footprint Properties using ALTO Property Map Service

   Besides retrieving footprints of given capabilities, another common
   requirement for uCDN is to query CDNI capabilities of given
   footprints.

   Considering each footprint as an entity with properties including
   CDNI capabilities, the most natrual way to satisfy this requirement
   is to use the ALTO property map defined in
   [I-D.ietf-alto-unified-props-new].  In this section, we describe how
   ALTO clients look up properties for individual footprints.  We
   firstly describe how to represent footprint objects as entities in
   the ALTO property map.  And then we provide examples of the full
   property map and the filtered property map supporting CDNI
   capabilities, and their incremental updates.






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6.1.  Representing Footprint Objects as Unified Property Map Entities

   A footprint object has two properties: footprint-type and footprint-
   value.  A footprint-value is an array of footprint values conforming
   to the specification associated with the registered footprint type
   ("ipv4cidr", "ipv6cidr", "asn", and "countrycode").  Considering each
   ALTO entity defined in [I-D.ietf-alto-unified-props-new] also has two
   properties: entity domain type and domain-specific identifier, a
   straightforward approach to represent a footprint as an ALTO entity
   is to regard its footprint-type as an entity domain type, and its
   footprint value as a domain-specific identifier.  According to
   [I-D.ietf-alto-unified-props-new], "ipv4" and "ipv6" are two
   predefined entity domain types, which can be used to represent
   "ipv4cidr" and "ipv6cidr" footprints respectively.  However, no
   existing entity domain type can represent "asn" and "countrycode"
   footprints.  To represent footprint-type "asn" and "countrycode",
   this document registers two new domains in Section 7 in addition to
   the ones in [I-D.ietf-alto-unified-props-new].

   Here is an example of representing a footprint object as a set of
   entities in the ALTO property map.

   {"footprint-type": "ipv4cidr", "footprint-value": ["192.0.2.0/24",
   "198.51.100.0/24"]} --> "ipv4:192.168.2.0/24", "ipv4:198.51.100.0/24"

6.1.1.  ASN Domain

   The ASN domain associates property values with Autonomous Systems in
   the Internet.

6.1.1.1.  Entity Domain Type

   asn

6.1.1.2.  Domain-Specific Entity Identifiers

   The entity identifiers of entities in an asn domain is encoded as a
   string consisting of the characters "as" (in lowercase) followed by
   the Autonomous System Number [RFC6793].

6.1.1.3.  Hierarchy and Inheritance

   There is no hierarchy or inheritance for properties associated with
   ASN.







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6.1.2.  COUNTRYCODE Domain

   The COUNTRYCODE domain associates property values with countries.

6.1.2.1.  Entity Domain Type

   countrycode

6.1.2.2.  Domain-Specific Entity Identifiers

   The entity identifiers of entities in a countrycode domain is encoded
   as an ISO 3166-1 alpha-2 code [ISO3166-1] in lowercase.

6.1.2.3.  Hierarchy and Inheritance

   There is no hierarchy or inheritance for properties associated with
   country codes.

6.2.  Examples

6.2.1.  IRD Example

   We use the same IRD example given by Section 3.7.1.

6.2.2.  Property Map Example

   This example shows a full property map in which entities are
   footprints and entities' property is "cdni-fci-capabilities".























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    GET /propmap/full/cdnifci HTTP/1.1
    HOST: alto.example.com
    Accept: application/alto-propmap+json,application/alto-error+json

    HTTP/1.1 200 OK
    Content-Length: ###
    Content-Type: application/alto-propmap+json

    {
      "property-map": {
        "meta": {
          "dependent-vtags": [
            {"resource-id": "my-default-cdnifci",
             "tag": "7915dc0290c2705481c491a2b4ffbec482b3cf62"}
          ]
        },
        "countrycode:us": {
          "my-default-cdnifci.cdni-fci-capabilities": [
            {"capability-type": "FCI.DeliveryProtocol",
             "capability-value": {"delivery-protocols": ["http/1.1"]}}]
        },
        "ipv4:192.0.2.0/24": {
          "my-default-cdnifci.cdni-fci-capabilities": [
            {"capability-type": "FCI.DeliveryProtocol",
             "capability-value": {"delivery-protocols": ["http/1.1"]}}]
        },
        "ipv4:198.51.100.0/24": {
          "my-default-cdnifci.cdni-fci-capabilities": [
            {"capability-type": "FCI.DeliveryProtocol",
             "capability-value": {"delivery-protocols": ["http/1.1"]}}]
        },
        "ipv6:2001:db8::/32": {
          "my-default-cdnifci.cdni-fci-capabilities": [
            {"capability-type": "FCI.DeliveryProtocol",
             "capability-value": {"delivery-protocols": ["http/1.1"]}}]
        },
        "asn:as64496": {
          "my-default-cdnifci.cdni-fci-capabilities": [
            {"capability-type": "FCI.DeliveryProtocol",
             "capability-value": {"delivery-protocols": ["http/1.1",
                                                         "https/1.1"]}}]
        }
      }
    }







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6.2.3.  Filtered Property Map Example

   In this example, we use filtered property map service to get "pid"
   and "cdni-fci-capabilities" properties for two footprints
   "ipv4:192.0.2.0/24" and "ipv6:2001:db8::/32".

      POST /propmap/lookup/cdnifci-pid HTTP/1.1
      HOST: alto.example.com
      Content-Type: application/alto-propmapparams+json
      Accept: application/alto-propmap+json,application/alto-error+json
      Content-Length:

      {
        "entities": [
          "ipv4:192.0.2.0/24",
          "ipv6:2001:db8::/32"
        ],
        "properties": [ "my-default-cdnifci.cdni-fci-capabilities",
                        "my-default-networkmap.pid" ]
      }































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    HTTP/1.1 200 OK
    Content-Length: ###
    Content-Type: application/alto-propmap+json

    {
      "property-map": {
        "meta": {
          "dependent-vtags": [
             {"resource-id": "my-default-cdnifci",
               "tag": "7915dc0290c2705481c491a2b4ffbec482b3cf62"},
             {"resource-id": "my-default-networkmap",
               "tag": "7915dc0290c2705481c491a2b4ffbec482b3cf63"}
          ]
        },
        "ipv4:192.0.2.0/24": {
          "my-default-cdnifci.cdni-fci-capabilities": [
            {"capability-type": "FCI.DeliveryProtocol",
             "capability-value": {"delivery-protocols": ["http/1.1"]}}],
          "my-default-networkmap.pid": "pid1"
        },
        "ipv6:2001:db8::/32": {
          "my-default-cdnifci.cdni-fci-capabilities": [
            {"capability-type": "FCI.DeliveryProtocol",
             "capability-value": {"delivery-protocols": ["http/1.1"]}}],
          "my-default-networkmap.pid": "pid3"
        }
      }
    }

6.2.4.  Incremental Updates Example

   In this example, here is a client want to request updates for the
   properties "cdni-fci-capabilities" and "pid" for two footprints
   "ipv4:192.0.2.0/24" and "countrycode:fr".

     POST /updates/properties HTTP/1.1
     Host: alto.example.com
     Accept: text/event-stream,application/alto-error+json
     Content-Type: application/alto-updatestreamparams+json
     Content-Length: ###

     { "add": {
       "property-map-including-capability-property": {
         "resource-id": "filtered-cdnifci-property-map",
           "input": {
             "properties": [ "my-default-cdnifci.cdni-fci-capabilities",
                             "my-default-networkmap.pid" ],
             "entities": [



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               "ipv4:192.0.2.0/24",
               "ipv6:2001:db8::/32"
             ]
           }
         }
     }

     HTTP/1.1 200 OK
     Connection: keep-alive
     Content-Type: text/event-stream

     event: application/alto-updatestreamcontrol+json
     data: {"control-uri":
     data: "http://alto.example.com/updates/streams/1414213562373"}

     event: application/alto-cdnifci+json,my-fci-stream
     data: { ... full filtered unified property map ... }

     event: application/merge-patch+json,my-fci-stream
     data: {
     data:   "property-map":
     data:   {
     data:     "meta": {
     data:       "dependent-vtags": [
     data:         {"resource-id": "my-default-cdnifci",
     data:          "tag": "2beeac8ee23c3dd1e98a73fd30df80ece9fa5627"},
     data:         {"resource-id": "my-default-networkmap",
     data:          "tag": "7915dc0290c2705481c491a2b4ffbec482b3cf63"}
     data:       ]
     data:     },
     data:     "ipv4:192.0.2.0/24":
     data:     {
     data:     "my-default-cdnifci.cdni-fci-capabilities": [
     data:       {"capability-type": "FCI.DeliveryProtocol",
     data:        "capability-value": {
     data:          "delivery-protocols": ["http/1.1"]}}]
     data:     }
     data:   }
     data: }

     event: application/json-patch+json,my-fci-stream
     data: {[
     data: {
     data:   { "op": "replace",
     data:     "path": "/meta/dependent-vtags/0/tag",
     data:     "value": "61b23185a50dc7b334577507e8f00ff8c3b409e4"
     data:   },
     data:   { "op": "replace",



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     data:     "path":
     data:     "/property-map/countrycode:fr/my-default-networkmap.pid",
     data:     "value": "pid5"
     data:   }
     data: }
     data: ]}

7.  IANA Considerations

7.1.  CDNI Metadata Footprint Type Registry

    +-----------------+-----------------------+-----------------------+
    | Footprint Type  | Description           | Specification         |
    +-----------------+-----------------------+-----------------------+
    | altopid         | A list of PID-names   | RFCthis               |
    +-----------------+-----------------------+-----------------------+

                   Table 1: CDNI Metadata Footprint Type

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

7.2.  ALTO Entity Domain Type Registry

   As proposed in Section 11.2 of [I-D.ietf-alto-unified-props-new],
   "ALTO Entity Domain Type Registry" is requested.  Besides, two new
   entity domain types are to be registered, listed in Table 2.

   +--------------+-------------------------+--------------------------+
   | Identifier   | Entity Address Encoding | Hierarchy & Inheritance  |
   +--------------+-------------------------+--------------------------+
   | asn          | See Section 6.1.1.2     | None                     |
   | countrycode  | See Section 6.1.2.2     | None                     |
   +--------------+-------------------------+--------------------------+

                     Table 2: ALTO Entity Domain Types

7.3.  ALTO Entity Property Type Registry

   As proposed in Section 11.3 of [I-D.ietf-alto-unified-props-new],
   "ALTO Entity Property Type Registry" is required.  Besides, a new
   entity property type is to be registred, listed in Table 3.









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   +------------------------+------------------------------------------+
   | Identifier             | Intended Semantics                       |
   +------------------------+------------------------------------------+
   | cdni-fci-capabilities  | An array of CDNI FCI capability objects  |
   +------------------------+------------------------------------------+

                   Table 3: ALTO CDNI FCI Property Type

8.  Security Considerations

   As an extension of the base ALTO protocol [RFC7285], this document
   fits into the architecture of the base protocol, and hence the
   Security Considerations (Section 15) of the base protocol fully apply
   when this extension is provided by an ALTO server.

   In the context of CDNI FCI, additional security considerations should
   be included as follows.

   For authenticity and integrity of ALTO information, an attacker may
   disguise itself as an ALTO server for a dCDN, and provide false
   capabilities and footprints to a uCDN using the CDNI FCI map.  Such
   false information may lead a uCDN to (1) select an incorrect dCDN to
   serve user requests or (2) skip uCDNs in good conditions.

   For potential undesirable guidance from authenticated ALTO
   information, dCDNs can provide a uCDN with limited capabilities and
   smaller footprint coverage so that dCDNs can avoid transferring
   traffic for a uCDN which they should have to transfer.

   For confidentiality and privacy of ALTO information, footprint
   properties integrated with ALTO unified property may expose network
   location identifiers (e.g., IP addresses or fine-grained PIDs).

   For availability of ALTO services, an attacker may get the potential
   huge full CDNI FCI maps from an ALTO server in a dCDN continuously to
   run out of bandwidth resources of that ALTO server or may query
   filtered CDNI FCI services with complex capabilities to run out of
   computation resources of an ALTO server.

   Protection strategies described in RFC 7285 can solve problems
   mentioned above well.  However, the isolation of full/filtered CDNI
   FCI maps should also be considered.

   If a dCDN signs agreements with multiple uCDNs, it must isolate full/
   filtered CDNI FCI maps for different uCDNs in that uCDNs will not
   redirect requests which should not have to served by this dCDN to
   this dCDN and it may not disclose extra information to uCDNs.




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   To avoid this risk, a dCDN may consider generating URIs of different
   full/filtered CDNI FCI maps by hashing its company ID, a uCDN's
   company ID as well as their agreements.  And it needs to avoid
   expoing all full/filtered CDNI FCI maps resources in one of its IRDs.

9.  Acknowledgments

   The authors would like to thank Daryl Malas, Matt Caulfield for their
   timely reviews and invaluable comments.

   Jan Seedorf is partially supported by the GreenICN project (GreenICN:
   Architecture and Applications of Green Information Centric
   Networking), a research project supported jointly by the European
   Commission under its 7th Framework Program (contract no. 608518) and
   the National Institute of Information and Communications Technology
   (NICT) in Japan (contract no. 167).  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 GreenICN project,
   the European Commission, or NICT.

10.  References

10.1.  Normative References

   [ISO3166-1]
              The International Organization for Standardization, "Codes
              for the representation of names of countries and their
              subdivisions -- Part 1: Country codes", ISO 3166-1:2013,
              2013.

   [RFC5693]  Seedorf, J. and E. Burger, "Application-Layer Traffic
              Optimization (ALTO) Problem Statement", RFC 5693,
              DOI 10.17487/RFC5693, October 2009,
              <https://www.rfc-editor.org/info/rfc5693>.

   [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>.

   [RFC6793]  Vohra, Q. and E. Chen, "BGP Support for Four-Octet
              Autonomous System (AS) Number Space", RFC 6793,
              DOI 10.17487/RFC6793, December 2012,
              <https://www.rfc-editor.org/info/rfc6793>.






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   [RFC7285]  Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
              Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
              "Application-Layer Traffic Optimization (ALTO) Protocol",
              RFC 7285, DOI 10.17487/RFC7285, September 2014,
              <https://www.rfc-editor.org/info/rfc7285>.

   [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>.

   [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>.

10.2.  Informative References

   [I-D.ietf-alto-incr-update-sse]
              Roome, W. and Y. Yang, "ALTO Incremental Updates Using
              Server-Sent Events (SSE)", draft-ietf-alto-incr-update-
              sse-17 (work in progress), July 2019.

   [I-D.ietf-alto-path-vector]
              Gao, K., Lee, Y., Randriamasy, S., Yang, Y., and J. Zhang,
              "ALTO Extension: Path Vector", draft-ietf-alto-path-
              vector-08 (work in progress), July 2019.

   [I-D.ietf-alto-unified-props-new]
              Roome, W., Randriamasy, S., Yang, Y., and J. Zhang,
              "Unified Properties for the ALTO Protocol", draft-ietf-
              alto-unified-props-new-08 (work in progress), July 2019.

   [I-D.jenkins-alto-cdn-use-cases]
              Niven-Jenkins, B., Watson, G., Bitar, N., Medved, J., and
              S. Previdi, "Use Cases for ALTO within CDNs", draft-
              jenkins-alto-cdn-use-cases-03 (work in progress), June
              2012.

Authors' Addresses










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   Jan Seedorf
   HFT Stuttgart - Univ. of Applied Sciences
   Schellingstrasse 24
   Stuttgart  70174
   Germany

   Phone: +49-0711-8926-2801
   Email: jan.seedorf@hft-stuttgart.de


   Y.R. Yang
   Tongji/Yale University
   51 Prospect Street
   New Haven, CT  06511
   United States of America

   Email: yry@cs.yale.edu
   URI:   http://www.cs.yale.edu/~yry/


   Kevin J. Ma
   Ericsson
   43 Nagog Park
   Acton, MA  01720
   United States of America

   Phone: +1-978-844-5100
   Email: kevin.j.ma@ericsson.com


   Jon Peterson
   NeuStar
   1800 Sutter St Suite 570
   Concord, CA  94520
   United States of America

   Email: jon.peterson@neustar.biz


   Xiao Shawn Lin
   Tongji University
   4800 Cao'an Hwy
   Shanghai  201804
   China

   Email: x.shawn.lin@gmail.com





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   Jingxuan Jensen Zhang
   Tongji University
   4800 Cao'an Hwy
   Shanghai  201804
   China

   Email: jingxuan.zhang@tongji.edu.cn












































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