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   Internet Draft     AAA Framework for Multicasting     October 2006



                                                     Hiroaki Satou, NTT
   Internet Draft                                     Hiroshi Ohta, NTT
   Expires: April 26, 2007          Christian Jacquenet, France Telecom
                                                 Tsunemasa Hayashi, NTT
                                           Haixiang He, Nortel Networks


                                                       October 23, 2006


                      AAA Framework for Multicasting
               <draft-ietf-mboned-multiaaa-framework-02.txt>


Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.


   Internet-Drafts are working documents of the Internet Engineering
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   http://www.ietf.org/shadow.html.



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   Internet Draft     AAA Framework for Multicasting     October 2006




   This Internet-Draft will expire on April 26, 2007.


Copyright Notice


   Copyright (C) The Internet Society (2006)


Abstract
   IP multicast-based services, such as TV broadcasting or
   videoconferencing raise the issue of making sure that potential
   customers are fully entitled to access the corresponding contents.
   There is indeed a need for service and content providers to identify
   (if not authenticate, especially within the context of enforcing
   electronic payment schemes) and to invoice such customers in a
   reliable and efficient manner. This memo describes the framework for
   specifying the Authorization, Authentication and Accounting (AAA)
   capabilities that could be activated within the context of the
   deployment and the operation of IP multicast-based services.  This
   framework addresses the requirements presented in draft-ietf-mboned-
   maccnt-req-04.txt, "Requirements for Accounting, Authentication and
   Authorization in Well Managed IP Multicasting Services".


1. Introduction

1.1 Purpose and Background
   IP multicasting is designed to serve cases of group communication
   schemes of any kind, such as 1-to-n (case of TV broadcasting
   services for example) or n-to-p (case of videoconferencing services,
   for example).
      In these environments, IP multicast provides a better resource
   optimization than using a unicast transmission scheme, where data
   need to be replicated as many times as there are receivers.
   Activation of IP multicast capabilities in networks yields the
   establishment and the maintenance of multicast distribution trees
   that are receiver-initiated by nature: multicast-formatted data are
   forwarded to receivers who explicitly request them.



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   Internet Draft     AAA Framework for Multicasting     October 2006



        IP multicast-based services, such as TV broadcasting or
   videoconferencing raise the issue of making sure that potential
   customers are fully entitled to access the corresponding contents.
   There is indeed a need for service and content providers to identify
   (if not authenticate, especially within the context of enforcing
   electronic payment schemes) and to invoice such customers in a
   reliable and efficient manner. This memo describes the framework for
   specifying the Authorization, Authentication and Accounting (AAA)
   capabilities that could be activated within the context of the
   deployment and the operation of IP multicast-based services.
        Specifically, this framework addresses the requirements
   presented in draft-ietf-mboned-maccnt-req-04.txt, "Requirements for
   Accounting, Authentication and Authorization in Well Managed IP
   Multicasting Services" MACCNT-REQ-draft describes the requirements
   in CDN services using IP multicast[1]. The requirements are derived
   from:
        - need for user tracking and billing capabilities
        - need for network access control to satisfy the requirements
   of the Network Service Provider (NSP) and/or content access control
   to satisfy the requirements of the Content Provider (CP)
        - methods for sharing information between the network service
   provider and content provider to make it possible to fulfill the
   above two requirements.

   Detailed requirements are presented in MACCNT-REQ-draft.   These
   requirements include mechanisms for recording end-user requests and
   provider responses for content-delivery, sharing user information
   (possibly anonymously depending on the trust model) between content
   provider and network service provider, and protecting resources
   through the prevention of network and content access by unauthorized
   users, as well as other AAA related requirements.

   The purpose of this memo is to provide a generalized framework for
   specifying multicast-inferred AAA capabilities that can meet these
   requirements. This framework is to provide a basis for future work
   of investigating the applicability of existing AAA protocols to
   provide these AAA capabilities in IP multicast specific context
   and/or if deemed necessary, the refining or defining of protocols to
   provide these capabilities.

   This draft's scope is limited to discussing SSM, 1-to-n IP
   multicasting exclusively.


2. Definitions and Abbreviations

2.1 Definitions

   For the purpose of this memo the following definitions apply:



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   Accounting: The set of capabilities that allow the retrieval of a
   set of statistical data that can be defined on a per customer and/or
   a per service basis, within the context of the deployment of
   multicast-based services. Such data are retrieved for billing
   purposes, and can be retrieved on a regular basis or upon
   unsolicited requests. Such data include (but are not necessarily
   limited to) the volume of multicast-formatted data that have been
   forwarded to the receiver over a given period of time, the volume of
   multicast-formatted data that have been exchanged between a receiver
   (or set of) and a given source over a given period of time (e.g. the
   duration of a multicast session), etc.

   Authentication: action for identifying a user as a genuine one.

   Authorization: The set of capabilities that need to be activated to
   make sure a given requesting customer is (1) what he claims to be
   (identification purposes), and (2) is fully entitled to access a set
   of services (authentication purposes).

   Receiver: an end-host or end-client which receives content.  A
   receiver may be identified by a network ID such as MAC address or IP
   address.

   User: a human with a user account.  A user may possibly use multiple
   reception devices.  Multiple users may use the same reception device.

   Note: The definition of a receiver (device) and a user (human)
   should not be confused.


2.2 Abbreviations

   For the purpose of this draft the following abbreviations apply:

   ACL: Access Control List

   CDN: Content Delivery Network

   CDS: Content Delivery Services

   CP: Content Provider

   NSP: Network Service Provider

   TP: Transit Provider




   Satou, Ohta, Hayashi, He                                   [Page 4]


3. Common use models and network architecture implications

   In some cases a single entity may design and be responsible for a
   system that covers the various common high-level requirements of a
   multicasting system such as 1) content serving, 2) the
   infrastructure to multicast it, 3) network and content access
   control mechanisms.  In many cases however the content provision and
   network provision roles are divided between separate entities.  The
   MACCNT-REQ-draft provides more detail of the multiple versus single
   entity CDS network model.

   As such it should not be assumed that the entity responsible for the
   multicasting structure and the entity responsible for content
   serving are the same.  Indeed because the infrastructure for
   multicasting is expensive and many content holders are not likely to
   be competent at building and maintaining complicated infrastructures
   necessary for multicasting, many content holders would prefer to
   purchase transport and management services from a network service
   provider and thus share the infrastructure costs with other content
   holders.

   Similarly network service providers in many cases do not specialize
   in providing content and are unlikely to build and maintain such a
   resource-intensive system without a certain level of demand from
   content holders.

   The use model of a single NSP providing multicasting services to
   multiple CPs the following general requirements from MACCNT-REQ-
   draft apply:

        -Need for user tracking and billing capabilities
        -Need for network access control and/or content access control
   satisfactory to the requirements of the CP
        -Methods for sharing information between the NSP and CP to make
   the above two possible


   When the NSP and CP are the same single entity the general
   requirements are as follows.

        -Need for user tracking and user-billing capabilities
        -Need for access control and/or content protection at level the
   entity deems appropriate



4. Framework and Roles of Entities


4.1 Framework for multicast AAA




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   Internet Draft     AAA Framework for Multicasting     October 2006


   A general high-level framework can be represented as follows.

            +------------------------------+
            |    user                      |
            |                              |
            +------------------------------+
                | Access       ^ Response
                | Request      | & Multicast Data
                V              |
            +------------------------------+
            |    NSP                       |
            |                              |
            +------------------------------+
                | Access         ^ Response
                | Request        | (Success)
                v                |
            +------------------------------+
            |    CP                        |
            |                              |
            +------------------------------+

   For the sake of simplicity, the above diagram portrays a case where
   there is a single NSP entity and a single CP entity, but multiple
   CPs can be connected to the same NSP. It is also possible for the
   same CP to be connected to multiple NSP networks (e.g. network
   selection).  In other words the relationship of NSP:CP can be
   described as  1:1, 1:N or M:N.  Furthermore it is possible that the
   NSP and CP could be the same entity.

   Description of Roles:

   The user (or the user's device) selects a CP and a NSP when the user
   requests content. The NSP may be automatically selected by a user
   terminal: e.g. a fixed line NSP for STB or a mobile NSP for mobile
   phone.  In some usage cases it is possible that the NSP used by the
   user terminal will not always be the same.  For example a user may
   have contracted with different NSPs for fixed line or mobile roaming
   access.

   The CP is responsible for Authentication and Authorization of users'
   access to content that the CP manages. The CP hopes to collect
   accounting information related to the access of their content. The
   CP may choose to authenticate and authorize NSPs which are eligible
   to provide users access to its contents.  When the CP cannot (e.g.
   error or resource issues) or decides not (e.g. policy issues) to
   deliver content, the CP is responsible for notifying the NSP of the
   reason.  It is up to the NSP how to relay or translate the messages
   to the user.




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   Internet Draft     AAA Framework for Multicasting     October 2006


   The NSP is responsible for managing its network resources.  The NSP
   may perform admission control. It is also responsible for relaying
   the AAA messages from the CP whether the user is eligible to receive
   content (authentication by proxy), and the NSPs relevant AAA server
   will make the final decision of whether the connection can be
   established.  When the NSP cannot or decides not to multicast to
   users, the NSP is responsible for notifying the users of the reason.


4.2 Multiple User IDs

   Users may hold multiple user IDs: IDs which have been separately
   assigned for each subscription they may have for various NSPs and
   CPs.  When the user wants to access content or otherwise use the
   network, the user registers the corresponding user ID with a request
   for content, etc: web authentication is one possible method.

   Terminal portability can be realized if the NSP authenticates a user
   using a user ID. This allows the user to access the content from
   various network access points.

   Each CP may identify users by the user IDs that it has issued to
   them.

   The NSP and CP do not need to know the corresponding user id for the
   same user in the other provider's domain, and it is not necessary
   that there is a one to one relationship.  It is quite possible for
   one person to hold multiple user ids for the same provider.

4.3 Accounting

   MACCNT-REQ-draft defines requirements for Accounting and Billing.
   These include the requirement for the NSP to log user behavior such
   as the join action and the leave action, as well as the result of
   the access-control decision. (MACCNT-REQ-draft, 4.5) MACCNT-REQ-
   draft also specifies that there should be a standardized format for
   sharing with the CP the user behavior and content reception
   information which the NSP is logging.(MACCNT-REQ-draft, 4.5.1)

   In order to provide the granularity of user-behavior and actual
   content reception information as specified in MACCNT-REQ-draft, the
   NSP should not manage multicast states on a subnet basis, but on a
   user basis (see in MACCNT-REQ-draft, 4.1 "User identification")
   because the NSP needs to be able to notify the CP of a user's start
   and stop times for accounting purposes. This means that the NSP
   sends to the CP AAA an indication for Join and Leave on a user basis.

   This framework specifies an accounting API provided by the NSP and
   accessed by the CP to allow for sharing user-behavior and content-
   reception information between the NSP AAA and CP AAA. This



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   accounting API should be configurable to allow the CP to request
   only the logging information it actually requires.  Such an API
   would allow for realtime accounting information sharing by the NSP
   to the CP. When logging information is shared through the accounting
   API, it is important that the CP be able to match the user as
   described in the database operated by the NSP to the user as
   described in the database operated by the CP.

   The NSP requires the capability to log both user and host
   information for each join and leave, indicating the corresponding
   multicast source for each action. When either a CP source stops
   sending, or the NSP stops multicasting, in an unsolicited manner,
   there is also a need to notify the AAA servers accordingly about the
   users who are impacted by this event.

   Also, intermittent logs between the join and leave would allow for
   finer diagnostics and therefore could serve useful in billing
   discrepancies, and provide for a better estimation of the time span
   that content was multicasted in the even that users disconnect
   without sending leave messages.



4.4 Access Control and CP selection by NSP

   When a NSP receives an access request from a user, it is necessary
   for the NSP to determine to which CP the request is to be directed.
   It is necessary for the NSP to ensure that it is not spoofed by an
   inappropriate CP or user.


4.5 API for Admission Control Information by NSP

   After authorizing a user request, the NSP may have further
   conditions for determining its admission control decision. MACCNT-
   REQ-draft defines requirements for providing the network capability
   to conduct admission control based on the network bandwidth usage
   status and bandwidth management policy. (MACCNT-REQ-draft, 4.2.2,
   4.2.3 & 4.9) Such QoS measurement and policy mechanisms themselves
   are out of the scope of this memo. However the NSP's AAA Server
   should be provided with an Admission control API that allows for
   interfacing so that additional conditions can be added to the
   admission control decision.


4.6 Access Control and Distinguishing of Users by CP

   The user ID and authentication information are forwarded
   transparently by the NSP so that the CP can distinguish the user, as
   well as authenticate and authorize the request.



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   Internet Draft     AAA Framework for Multicasting     October 2006



4.7 Caching of AAA results

   An NSP should be able to cache AAA results based upon an agreement
   between the NSP and a CP.  The AAA cache would store information
   about permissions of a specific user to receive multicast data from
   specified channel(s) up to specified expiration date(s) and time(s).
   If such caching is implemented, a method must exist for the CP to
   communicate this permission information to the NSP.  The NSP refers
   to the AAA cache and if the cache indicates that the user has
   permission to receive multicast data from a specific channel at that
   time, the NSP may forward the data without querying the CP.

   It should be possible for a CP to send unsolicited requests to the
   NSP to refresh or change the permissions for a user for specific
   channel(s).

   When a user is receiving multicast content and the permission is
   about to expire, the NSP may send a notification to the user client
   that his session is about to expire, and that he will need to re-
   connect. The user will have to reestablish a connection.  In the
   case that the user still has permission to the content, they should
   be able to continue to receive the content without interruption.


5. Network Connection Model and Functional Components

   Section 3.1 introduces the high-level AAA framework for multicasting.
   This section provides more detail on the network connection model
   and constituent functional components.

5.1 Basic Connection Model

                  +-------------+
                  |     user    |
                  |             |
                  +-------------+
                          ^ Access & Resource
                          | Request
                          v
                  +-------------+
                  |     NSP     |
                  |             |
                  +-------------+
                          ^ Access
                          | Request
                          v
                  +-------------+
                  |     CP      |
                  |             |



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   Internet Draft     AAA Framework for Multicasting     October 2006


                  +-------------+

   First a user that requests content sends an Access request to an NSP
   which then forwards it on to the appropriate CP for Authentication
   and Authorization purposes. The CP responds with either "success" or
   "failure".  If "success", the NSP may forward a success response and
   stream multicast data to the user.

   In this model the user selects the NSP to which to send its content
   request.  Based on this request the NSP selects an appropriate CP to
   which it forwards the request. The CP responds to the NSP's request:
   it may not respond to another NSP in regards to the request.

   In this model, as described in section 3.1, the relationship between
   NSP and CP can be 1:1, 1:N or M:N.  Users may connect to multiple
   networks, and networks have multiple users.




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   Internet Draft     AAA Framework for Multicasting     October 2006


5.2 Transit Provision

   The diagram below shows that a Transit Provider(hereafter, TP)  may
   relay requests between NSPs and CPs.

                  +-------------+
                  |     user    |
                  |             |
                  +-------------+
                          ^ Access & Resource
                          | Request
                          v
                  +-------------+
                  |     NSP     |
                  |             |
                  +-------------+
                          ^ Access & Resource
                          | Request
                          v
                  +-------------+
                  |     TP      |
                  |             |
                  +-------------+
                          ^ Access
                          | Request
                          v
                  +-------------+
                  |     CP      |
                  |             |
                  +-------------+

   For the sake of simplification the above diagram shows a 1-1
   relationship between an NSP and a TP.  However it is also possible
   for a single NSP to connect to multiple TPs, and a single TP to
   multiple NSPs.

   A single TP may connect to one or more CPs. Similarly just as a
   single CP may connect to multiple NSPs (as described in the general
   high-level framework, section 3.1), a single CP may connect to one
   or more TPs.

   A solution will include a mechanism through which the NSPs know
   which TP(s) are to be used to communicate with which CP(s), and CPs
   know which TP(s) to use for which NSP(s).  When a TP receives an
   access or resource request from an NSP or CP, it must relay the
   request to the correct CP or NSP, respectively.  Minimally, this
   means that it must reconstruct the request with translated address
   information.  In this model therefore a TP must understand the
   format and meaning of the requests.




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   Internet Draft     AAA Framework for Multicasting     October 2006


   There may be multiple TPs between a NSP and CP so that a TP is
   actually receiving from and/or sending requests to another TP and
   not directly from/to a NSP or CP.

5.3 Transit with Tunnels

   In addition to the above model of request relaying, a TP may
   communicate requests through tunneling based on the contract between
   the TP and the NSP and/or between the TP and the CP.  So in this
   case the TP will not directly need to process the contents of the
   access and resource request (such as, header information), but
   instead pass the request directly to the correct NSP or CP, using a
   separate protocol to wrap the original requests.

   Below is a diagram, representing how a TP can provide tunneling
   between NSP(s) and CP(s).

                  +-----------------+
                  |     user        |
                  |                 |
                  +-----------------+
                          ^ Access & Resource
                          | Request
                          v
                  +------------------+
                  |       NSP        |
                  |                  |
                  +------------------+
                    |^|
                    |:|
                    |:|
                  +-|:|--------------+
                  | |:|   TP         |
                  | |:|              |
                  +-|:|--------------+
                    |:|
                    |:| Tunnel
                    |:|
                    |V|
                  +------------------+
                  |       CP         |
                  |                  |
                  +------------------+

   In this model too, the relationship between NSP and TP and between
   transit provider and CP can be 1:1, 1:N or M:N.




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   Internet Draft     AAA Framework for Multicasting     October 2006


5.4 Constituent Logical Functional Components of the fully enabled AAA
Framework

   Section 3.1 introduces the high-level AAA framework for multicasting.
   Below is a diagram of a fully enabled multicasting network with AAA,
   including the logical components within the various entities.


            +-------------------------------+
            |            user               |
            |                               |
            +-------------------------------+
                          ^
                          | Access & resource request
                          v
            +-------------------------------+
            |            NSP                |
            |                               |
            |+--------------+    +---------+|
            ||NR Management |<-->|AAA Proxy||    (NR= network resource)
            |+--------------+ RR +---------+|    (RR= resource request)
            +-------------------------------+
                          ^
                          | Access request
                          v
            +------------------------------+
            |             CP               |
            |                              |
            |         +---------+          |
            |         |   AAA   |          |
            |         +---------+          |
            +------------------------------+

   In the fully enabled model the NSP provides proxying of
   authentication and authorization between the NSP and CP, as well as
   user-based accounting.  The AAA proxy server of the NSP communicates
   with the CP's AAA server.  Although not shown in the above diagram
   for the sake of simplicity, in addition to direct proxying between a
   NSP and CP, this proxying may be done through a TP.  This means that
   the transit provider is also cable of supporting AAA proxying.

   In the fully enabled model the NSP also includes a component that
   provides network resource management (e.g. QoS management), as
   described in section 3.4, "Network Resource Management by NSP".
   When a transit provider is used it may also provide Network Resource
   management of its own resources.

5.5 Modularity of the framework




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   Internet Draft     AAA Framework for Multicasting     October 2006


   In the interest of flexibility, this framework is modular so that it
   is possible that partially enabled versions of the models are
   supported.  A AAA-enabled version provides AAA functionality without
   Network Resource management.  A Network-Resource-Management-enabled
   (QoS-enabled) version provides Network Resource management without
   AAA functionality.  Similarly, the possibility of one or more layers
   of transit provision between an NSP and CP is in the interest of
   modularity and extendibility.


6. IANA considerations

   This memo does not raise any IANA consideration issues.


7. Security considerations

   Refer to section 3.3.  Also the user information related to
   authentication with the CP must be protected in some way.  Otherwise,
   this memo does not raise any new security issues which are not
   already addressed by the original protocols.  Enhancement of
   multicast access control capabilities should enhance security
   performance.


8. Conclusion

   This memo provides a generalized framework for solution standards to
   meet the requirements presented in MACCNT-REQ-draft.  Further work
   should be done to break down the content provider and network
   service provider entities into their functional objects such as edge
   devices, AAA servers, etc.


Normative References

   [1] Hayashi, et. al., "Accounting, Authentication and Authorization
       Issues in Well Managed IP Multicasting Services", draft-ietf-
       mboned-maccnt-req-04.txt, February 2006, Work in Progress.


Authors' Addresses

           Hiroaki Satou
           NTT Network Service Systems Laboratories
           3-9-11 Midoricho, Musashino-shi, Tokyo, 180-8585 Japan
           Phone : +81 422 59 4683
           Email : satou.hiroaki@lab.ntt.co.jp

           Hiroshi Ohta



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   Internet Draft     AAA Framework for Multicasting     October 2006


           NTT Network Service Systems Laboratories
           3-9-11 Midoricho, Musashino-shi, Tokyo, 180-8585 Japan
                   Phone : +81 422 59 3617
           Email: ohta.hiroshi@lab.ntt.co.jp

           Christian Jacquenet
           France Telecom
           3, avenue Francois Chateau
           CS 36901, 35069 Rennes Cedex, France
           Phone: +33 2 99 87 63 31
           Email: christian.jacquenet@francetelecom.com

           Tsunemasa Hayashi
           NTT Network Innovation Laboratories
           1-1 Hikari-no-oka, Yokosuka-shi, Kanagawa, 239-0847 Japan
           Phone: +81 46 859 8790
           Email: tsunemasa@gmail.com

           Haixiang He
           Nortel
           600 Technology Park Drive
           Billerica, MA 01801, USA
           Phone: +1 978 288 7482
           Email: haixiang@nortel.com


Comments

   Comments are solicited and should be addressed to the mboned working
   group's mailing list at mboned@lists.uoregon.edu_and/or the authors.



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   Internet Draft     AAA Framework for Multicasting     October 2006



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Expiration

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Acknowledgement

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   Internet Society.



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