One document matched: draft-ietf-mboned-maccnt-req-04.txt

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                                                 Tsunemasa Hayashi, NTT 
     Internet Draft                                 Haixiang He, Nortel 
     Document:draft-ietf-mboned-maccnt-req-04.txt    Hiroaki Satou, NTT 
     Expires: August 12, 2006                         Hiroshi Ohta, NTT 
                                         Susheela Vaidya, Cisco Systems 
                                                                        
                                                                        
                                                       February 8, 2006 
      
      
      Requirements for Accounting, Authentication and Authorization in 
                    Well Managed IP Multicasting Services 
                    <draft-ietf-mboned-maccnt-req-04.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 
     Task Force (IETF), its areas, and its working groups.  Note that 
     other groups may also distribute working documents as Internet-
     Drafts. 
      
     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." 
      
     The list of current Internet-Drafts can be accessed at 
     http://www.ietf.org/ietf/1id-abstracts.txt. 
      
     The list of Internet-Draft Shadow Directories can be accessed at 
     http://www.ietf.org/shadow.html. 
      
     This Internet-Draft will expire on August 12, 2006. 
      
      
  Copyright Notice 
      
     Copyright (C) The Internet Society (2006) 
      
      
  Abstract 
      
     This memo presents requirements in the area of accounting and 
     access control for multicasting.  General requirements for 
   
   
   
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     accounting capabilities including quality-of-service (QoS) related 
     issues are listed.  Finally, cases for Content Delivery Services 
     (CDS) are described as application examples which could benefit 
     from multicasting accounting and access control capabilities as 
     described in the I-D.  It is proposed that this I-D be used as a 
     starting point for further discussion on these issues. 
   
   
   
                              Table of Contents 
   
     Copyright Notice..................................................1 
     1. Introduction...................................................2 
     2. Definitions and Abbreviations..................................4 
     2.1 Definitions...................................................4 
     2.2 Abbreviations.................................................4 
     3. Problem Statement..............................................5 
     3.1  Accounting Issues............................................5 
     3.2  Relationship with Secure Multicasting (MSEC).................7 
     3.3  Regarding Access Media and User Separation...................7 
     4. General AAA-related Functional Requirements for IP Multicast...7 
     5. Application Example and its Specific Requirements.............13 
     5.1 IP Multicast-based Content Delivery Service (CDS): CP and NSP 
     are different entities (companies)...............................13 
     5.1.1 Network Model for Multicast Content Delivery Service.......13 
     5.1.2 Content Delivery Service Requirements......................15 
     5.1.2.1 Accounting Requirements..................................15 
     5.1.2.2 Authorization Requirements...............................16 
     5.1.2.3 Authentication Requirements..............................17 
     5.2 IP Multicast-based Content Delivery Service (CDS): CP and NSP 
     are the same entities (companies)................................17 
     6. Acknowledgments...............................................18 
     7. IANA Considerations...........................................19 
     8. Security Considerations.......................................19 
     9. Conclusion....................................................19 
     Normative References.............................................19 
     Authors' Addresses...............................................20 
     Full Copyright Statement.........................................21 
     Intellectual Property............................................21
   
   
  1. Introduction 
      
     This I-D will present general functional requirements related to 
     accounting, authentication and authorization issues in IP 
     multicasting networks. A multicast network which fulfills all of 
   
   
   
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     these requirements will be called a "fully AAA enabled" IP 
     multicasting network. Fulfillment of all or some of the 
     requirements will make possible more robust management of IP 
     multicasting networks, and as such these capabilities contribute 
     to the provision of well-managed IP multicasting services. 
      
     IP multicasting is becoming widely used as a method to save 
     network resources such as bandwidth or CPU processing power of the 
     sender's server for cases where a large volume of information 
     needs to be distributed to a large number of receivers.  This trend 
     can be observed both in enterprise use and in broadband services 
     provided by network operator/service providers. 
      
     Distance learning within a university and in-house (in-company) 
     sharing of multimedia information are examples of enterprise use.  
     In these examples, sources generate high-bit rate (e.g., 6Mbit/s) 
     streaming information.  When the number of receivers becomes large, 
     such systems do not scale well without multicasting. 
      
     On the other hand, a Content Delivery Service (CDS) is an example 
     of a broadband service provided by network operators/service 
     providers.  Distribution of movies and other video programs to each 
     user are typical services.  Each channel requires large bandwidth 
     (e.g., 6Mbit/s) and operator/service providers need to provide 
     many channels to make their service attractive.  In addition, the 
     number of receivers is large (e.g., more than a few thousands).  
     The system to provide this service does not scale well without 
     multicasting. 
      
     As such, multicasting can be useful to make the network more 
     scalable when a large volume of information needs to be 
     distributed to a large number of receivers.  However, multicasting 
     according to current standards (e.g., IGMPv3[1] and MLDv2[2]) has 
     drawbacks compared to unicasting when one applies it to commercial 
     services.  Accounting of each user's actions is not possible with 
     multicasting as it is with unicasting.  Accounting consists of 
     grasping each user's behavior, when she/he starts/stops to receive 
     a channel, which channel she/he receives, etc. 
      
     IP multicasting can be used to distribute free material 
     efficiently, but there are limitations to multicasting in usage 
   
   
   
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     models where usage accounting is necessary, such as many 
     commercial applications. These limitations have prevented the 
     widespread deployment of multicasting.  Alternatively, one could 
     develop and use a proprietary solution to address this issue.  
     However, non-standard solutions have drawbacks in terms of 
     interoperability or cost of development and maintenance. 
      
     Without accounting capability in multicasting, information 
     providers desiring accounting capability are forced to use 
     unicasting even when multicasting would otherwise be desirable 
     from a bandwidth/server resource perspective.  If multicasting 
     could be used with user-based accounting capabilities, its 
     applicability would be greatly widened. 
      
     This I-D first describes problems on accounting issues in 
     multicasting.  Then the general requirements for this capability 
     including QoS related issues are listed.  Finally, application 
     examples which could benefit from multicasting with accounting 
     capabilities are shown.  It is proposed that this I-D be used as a 
     starting point for a discussion on these issues. 
      
      
  2. Definitions and Abbreviations 
   
  2.1 Definitions 
      
     Authentication: action for identifying a user as a genuine one. 
   
     Authorization: action for giving permission for a user to access 
     content or the network. 
      
     Eligible user: Users may be eligible (permitted) to access   
     resources because of the attributes they have (e.g., delivery may 
     require possession of the correct password or digital certificate), 
     their equipment has (e.g., content may only be eligible to players 
     that can decode H.264 or 3GPP streams), their edge network has 
     (e.g., HD content may only be eligible to users with 10 Mbps or 
     faster edge connections), or because of where they are in network 
     topology (e.g., HD content may not be eligible for users across 
     congested links) or in actual geography (e.g., content may only be 
   
   
   
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     licensed for distribution to certain countries), and, of course, a 
     mix of attributes may be required for eligibility or ineligibility. 
      
     User-based accounting: actions for grasping each user's behavior, 
     when she/he starts/stops to receive a channel, which channel 
     she/he receives, etc. 
      
      
  2.2 Abbreviations 
   
     ASM: Any-Source Multicast  
      
     CDS: Content Delivery Service 
      
     CP: Content Provider 
      
     IGMP: Internet Group Management Protocol 
      
     MLD: Multicast Listener Discovery 
      
     NSP: Network Service Provider 
      
     SSM: Single-Source Multicast 
      
     QoS: Quality of Service 
      
      
      
  3. Problem Statement 
      
  3.1  Accounting Issues 
      
     In unicast communications, the server (information source) can 
     identify the client (information receiver) and only permits 
     connection by an eligible client when this type of access control 
     is necessary.  In addition, when necessary, the server can grasp 
     what the client is doing (e.g., connecting to the server, starting 
     reception, what information the client is receiving, terminating 
     reception, disconnecting from the server). 
      
   
   
   
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     On the other hand, in multicast communication with current 
     standards (e.g., IGMPv3[1] or MLDv2[2]) the server just feeds its 
     information to the multicast router [as in Fig.1].  Then, the 
     multicast router replicates the data to any link which has at 
     least one client requesting the information.    In this process, no 
     eligibility check is conducted.  Any client can receive information 
     just by requesting it.  In other words, the current standards do 
     not provide multicasting with authorization or access control 
     capabilities sufficient to meet the requirements of accounting. 
      
      
       +--------+ 
       | user   |\ 
       +--------+ \ 
                   \+------+    +------+    +------+    +------+ 
       +--------+   |Multi-|    |Multi-|    |Multi-|    |      | 
       | user   |---|cast  |----|cast  |----|cast  |----|Server| 
       +--------+   |router|    |router|    |router|    |      | 
                   /+------+    +------+    +------+    +------+ 
       +--------+ / 
       | user   |/ 
       +--------+ 
      
              Fig.1 Example network for multicast communication 
      
     This is the major reason why multicasting is only used for cases 
     where no user-based accounting capabilities are necessary.    
     However, since more and more information is transferred over IP-
     based networks and some of these applications may require 
     accounting capabilities, it is easy to envision the requirement of 
     supporting such cases.  For example, accounting is needed if one 
     wants to charge for distributed information on a non-flat-fee 
     basis.  If the volume of information and number of clients are 
     large, it is beneficial to use multicasting for purposes of 
     network resource efficiency. 
      
     As such, the same level of user-based accounting capabilities as 
     provided in unicast networks should be provided in multicast 
     networks. 
      
      
   
   
   
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  3.2  Relationship with Secure Multicasting (MSEC) 
      
     In many cases, content encryption (e.g. MSEC) is an effective 
     method for preventing unauthorized access to original content (in 
     other words, the ability to decode data to return it to its 
     generally usable form.)  This I-D presents requirements for 
     multicasting networks in the areas of 1) access control to prevent 
     unauthorized access to the network, and 2) accounting to grasp 
     user activity.  The functional requirements do not require content 
     encryption although it might solve some of the related problems.  
     At this point, it is not yet clear whether encryption would be 
     part of a solution and if so, what other components (if any) would 
     also be required. 
      
  3.3  Regarding Access Media and User Separation 
   
     The requirements defined in this memo apply to solutions that  
     provide user separation either through physical separation  
     provided by dedicated access media between the user and multicast 
     router  (see  Fig.  1) or else through logical separation in cases 
     of shared physical access media (e.g. using VLAN). However, IP 
     multicast solutions with shared Layer 2 access media between the 
     user and multicast router and no logical user separation (e.g. 
     Ethernet with shared links and no VLAN) are out of scope of this 
     memo. Nevertheless, some of the requirements in this memo defined 
     for multicasting may also be relevant to multicasting over links 
     without either physical or logical user separation.  Therefore in 
     the interest of modularity and flexibility, solutions addressing 
     the requirements of this memo may also take into account 
     application to multicasting without such user separation. 
      
  4. General AAA-related Functional Requirements for IP Multicasting 
      
     In consideration of the issues presented in section 3, the 
     following requirements have been derived: 
      
      
     (1) User identification 
      
     The network should be able to identify each user when they attempt 
     to access the service so that necessary access controlling actions 
   
   
   
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     can be applied.  Also, it is necessary to identify the source 
     (user) of each request (e.g., join/leave) for user accounting 
     purposes. 
      
     With current protocols (IGMP/MLD), the sender cannot distinguish 
     which receivers (end hosts) are actually receiving the information.  
     The sender must rely on the information from the multicasting 
     routers. This can be complicated if the sender and routers are 
     maintained by different entities. 
      
   
     (2) Issue of Network Resource Protection 
      
     In order to guarantee certain QoS it is important for network 
     providers to be able to protect their network resources from being 
     wasted, (either maliciously or accidentally). 
      
     For comparisons sake, in the case of unicast this issue can be 
     resolved e.g. by using RSVP. 
      
      
     (2.1) Access control 
      
     The network should be able to apply necessary access controlling 
     actions when an eligible user requests an action (such as a join 
     or a leave.)  The network should be able to reject any action 
     requested from an ineligible user.  
      
   
     (2.2) Control mechanism to support bandwidth of multicast stream 
          from a physical port of edge router or switch 
      
     The network may need to control the combined bandwidth for all 
     groups at the physical port of the edge router or switch so that 
     these given physical entities are not overflowed with traffic. 
      
      
     (2.3) Control mechanism of number of groups delivered from a 
          physical port of edge router and switch 
      
   
   
   
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     If an NSP desires to guarantee a certain level of QoS to CP and 
     the receivers, it is necessary that the NSP be able to control the 
     number of groups delivered from a physical port of an edge router 
     and a switch so that the combined bandwidth between content 
     servers and multicast routers can be within the limit. 
      
     For comparisons sake, in the case of unicast this issue can be 
     resolved e.g. by using RSVP. 
      
      
     (3) User Authentication 
      
     The network should be able to authenticate a user. 
      
      
     (4) User Authorization 
      
     The network, at its option, should be able to authorize a user's 
     access to content or a multicast group, so as to meet any demands 
     by a CP to prevent content access by ineligible users.  In the case 
     that the NSP may wish to provide a service based on guaranteed 
     delivery, the NSP would not want to waste its network resources on 
     ineligible users.   
      
      
     (5) Accounting and Billing 
      
     In many commercial multicast situations, NSPs would like to be 
     able to precisely grasp network resource consumption and CPs would 
     like to be able to precisely grasp the content consumption by end-
     users.  Such information might be used for identifying highly 
     viewed content for advertising revenue, ratings calculations, 
     programming decisions, etc., as well as billing and auditing 
     purposes. Also content and network providers may wish to provide 
     users with access to their usage history. 
      
     To assemble such an understanding of end-user behavior, it is 
     necessary to precisely log information such as who (host/user) is 
     accessing what content at what time (join action) until what time 
     (leave action).  The result of the access-control decision (e.g. 
     results of authorization) would also be valuable information.  The 
   
   
   
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     desired degree of logging precisions would depend on the 
     application used. 
      
     (5.1) How to share user information 
      
     For commercial multicast applications it is important for NSP and 
     CP to be able to share information regarding user's behaviour (as 
     described in (5) in standardized ways.  
      
      
     (6) Notification to Users of the Result of the Join Request 
      
     It should be possible to provide information to the user about the 
     status of his/her join request(granted/denied/other). 
      
      
     (7) Service and Terminal Portability 
      
     Depending on the service, networks should allow for a user to 
     receive a service from different places and/or with a different 
     terminal device. 
      
      
     (8) Support of ASM and SSM 
      
     Both ASM (G), and SSM (S,G) should be supported as multicast 
     models. 
      
      
     (9) Admission Control for Join Action 
      
     In order to maintain a predefined QoS level, depending on the 
     NSP's policy, an edge router should be able to control the number 
     of streams it serves to a user, and total bandwidth consumed to 
     that user. For example if the number of streams being served to a 
     certain user has reached the limit defined by the NSP's policy, 
     then the edge router should not accept a subsequent "join" until 
     one of the existing streams is terminated.  Similarly, if the NSP 
     is controlling by per-user bandwidth consumption, then a 
     subsequent "join" should not be accepted if delivery of the 
   
   
   
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     requested stream would push the consumed bandwidth over the NSP 
     policy-defined limit. 
      
      
     (10)  Channel Join Latency and Leave Latency 
      
     Commercial implementations of IP multicasting are likely to have 
     strict requirements in terms of user experience.  Join latency is 
     the time between when a user sends a "join" request and when the 
     requested data streaming first reaches the user.  Leave latency is 
     the time between when a user sends a "leave" signal and when the 
     network stops streaming to the user. 
   
     Leave and Join latencies impact the acceptable end-user experience 
     for fast channel surfing. In an IP-TV application, users are not 
     going to be receptive to a slow response time when changing 
     channels.  If there are policies for controlling the number of 
     simultaneous streams a user may access then channel surfing will 
     be determined by the join and leave latencies. 
      
     Furthermore, leave affects resource consumption:  with a low "leave 
     latency" network providers could minimize streaming content when 
     there are no audiences. 
   
     It is important that any overhead for authentication, 
     authorization, and access-control be minimized at the times of 
     joining and leaving multicast groups so as to achieve join and 
     leave latencies acceptable in terms of user experience. For 
     example this is important in an IP-TV application, because users 
     are not going to be receptive to a slow response time when 
     changing channels. 
      
      
     (11)  Scalability 
      
     Solutions that are used for well managed IP multicasting should 
     scale enough to support the needs of content providers and network 
     operators. 
      
      
     (12) Small Impact on the Existing Products 
   
   
   
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     Impact on the existing products (e.g., protocols, software, etc.) 
     should be as minimal as possible. 
      
     Ideally the NSP should be able to use the same infrastructure 
     (such as access control) to support commercial multicast services 
     for the so called "triple play" services: voice (VoIP), video, and 
     broadband Internet access services. 
      
     When a CP requires the NSP to provide a level of QoS surpassing 
     "best effort" delivery or to provide special services (e.g., to  
     limited users with specific attributes), certain parameters of the 
     CDS may be defined by a contractual relation between the NSP and 
     the CP.  However, just as for best-effort unicast, multicast allows 
     for content sourced by CPs without a contractual relation with the 
     NSP.  Therefore,  solutions addressing the requirements defined in 
     this memo should not make multicasting without AAA features 
     obsolete. NSPs may offer tiered services, with higher 
     QOS,accounting, authentication, etc., depending on contractual 
     relation with the CPs. It is therefore important that Multicast 
     AAA and QoS functions be as modular and flexible as possible. 
      
     (13) Deployable as Alternative to Unicast 
      
     IP Multicasting would ideally be available as an alternative to IP 
     unicasting when the "on-demand" nature of unicasting is not 
     required. Therefore interfaces to multicasting should allow for 
     easy integration into CDS systems that support unicasting.  
     Especially equivalent interfaces for authorization, access control 
     and accounting capabilities should be provided. 
      
      
     (14) Multicast Replication 
      
     The above requirements should also apply if multicast replication 
     is being done on an access-node (e.g. DSLAMs or OLTs). 
      
      
     Specific functional requirements for each application can be 
     derived from the above general requirements.  An example is shown 
     in the section 5. 
   
   
   
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  5. Application Example and its Specific Requirements 
      
     This section shows an application example which could benefit from 
     multicasting.  Then, specific functional requirements related to 
     user-based accounting capabilities are derived. 
      
      
  5.1 IP Multicast-based Content Delivery Service (CDS): CP and NSP are 
     different entities (companies) 
   
     Broadband access networks such as ADSL (Asymmetric Digital 
     Subscriber Line) or FTTH (Fiber to the Home) have been deployed 
     widely in recent years. Content Delivery Service (CDS) is expected 
     to be a major application provided through broadband access 
     networks. Because many services such as television broadcasting 
     require huge bandwidth (e.g., 6Mbit/s) and processing power at 
     content server, IP multicast is used as an efficient delivery 
     mechanism for CDS.  
      
     One way to provide high quality CDS is to use closed networks 
     ("walled-garden" model). 
      
     This subsection shows an example where CP and NSP are different 
     entities (companies). 
      
   
  5.1.1 Network Model for Multicast Content Delivery Service 
      
     As shown in Fig.2, networks for CDS contain three different types 
     of entities: Content Provider (CP), Network Service Provider (NSP), 
     and end user clients. An NSP owns the network resources 
     (infrastructure). It accommodates content providers on one side 
     and accommodates end user clients on the other side. NSP provides 
     the network for CDS to two other entities (i.e., CPs and end user 
     clients). A CP provides content to each end-user client through 
     the network of NSPs. NSPs are responsible for delivering the 
     content to end user clients, and for controlling the network 
     resources. 
      
   
   
   
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       +-------------+  +-------------+  +-------------+ 
       | CP          |  | CP          |  | CP          | 
       |          #1 |  |          #2 |  |          #3 | 
       | +---------+ |  | +---------+ |  | +---------+ | 
       | | content | |  | | content | |  | | content | | 
       | | server  | |  | | server  | |  | | server  | | 
       | +-------+-+ |  | +----+----+ |  | +-+-------+ | 
       +----------\--+  +------|------+  +--/----------+ 
                   \           |           / 
                    \          |          / <- network/network 
                     \         |         /     interface 
       +------------- \ ------ | ------ / ----+ 
       |               \       |       /      | 
       |   NSP         +-+-----+-----+-+      | 
       |               | Provider Edge |      | 
       |               +-------+-------+      |   +-----------------+ 
       |                       |              |---| Information     | 
       |                       |              |   | server          | 
       |             +--+------+---+          |   +-----------------+ 
       |             | User Edge   |          | 
       |             +--+---+---+--+          | 
       |               /    |    \            | 
       +------------- / --- | --- \ ----------+ 
                     /      |      \ 
                    /       |       \ <- user/network interface 
                   /        |        \ 
        +---------++  +-----+----+   ++---------+ 
        |client #a |  |client #b |   |client #c | 
        +----------+  +----------+   +----------+ 
        End user A    End user B     End user C 
       
                 Fig.2 Example of CDS network configuration 
                                                                          
       
     The NSP provides the information server for all multicast channels, 
     and a CP gives detailed channel information (e.g., Time table of 
     each channel) to the information server. An end-user client gets 
     the information from the information server. In this model, 
     multicast is used in the NSP's CDS network, and there are two 
     different contracts. One is the contract between the NSP and the 
   
   
   
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     end user which permits the user to access the basic network 
     resources of the NSP.  Another contract is between the CP and end 
     user to permit the user to subscribe to multicast content. Because 
     the CP and NSP are different entities, and the NSP generally does 
     not allow a CP to control (operate) the network resources of the 
     NSP, user authorization needs to be done by the CP and NSP 
     independently. Since there is no direct connection to the 
     user/network interface, the CP cannot control the user/network 
     interface. An end user may want to move to another place, or may 
     want to change her/his device (client) anytime without 
     interrupting her/his reception of services.  As such, IP Multicast 
     network should support portability capabilities. 
      
      
  5.1.2 Content Delivery Service Requirements 
   
     To have a successful business providing multicast, there are some 
     specific requirements for the IP Multicast-based Content Delivery 
     Service. 
   
   
  5.1.2.1 Accounting Requirements 
      
     Since the CP and NSP are different business entities, they need to 
     share the revenue. Such a revenue sharing business relationship 
     requires accurate and near real-time accounting information about 
     the end user clients' activity on accessing the content services. 
     The accounting information should be per content/usage-base to 
     enable varied billing and charging methods. 
      
     The user accessing particular content is represented by the user's 
     activities of joining or leaving the corresponding multicast 
     group/channel (<g> or <s,g>). In multicast networks, only NSPs can 
     collect group joining or leaving activities in real-time through 
     their last-hop multicast access edge devices. The NSPs can 
     transfer the accounting information to related CPs for them to 
     generate end user billing information. The normal AAA technology 
     can be used to transfer the accounting information. 
      
     To match the accounting information with a particular end-user 
     client, the end-user client has to be authenticated. Usually the 
   
   
   
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     account information of an end-user client for content access is 
     maintained by the CP. An end user client may have different user 
     accounts for different CPs. The account is usually in the format 
     of (username, password) so an end user client can access the 
     content services from anywhere. For example, an end user client 
     can access the CP from different NSPs. It should be noted that the 
     user account used for content access can be different from the one 
     used for network access maintained by NSPs. 
      
     The NSP-CP model represents a multi-domain AAA environment. There 
     are plural cases of the model depending on the trust relationship 
     between the NSP and CP, and additional service requirements such 
     as a certain QoS level guarantee or service/terminal portability. 
      
     A mechanism is necessary to allow a CP and NSP to grasp each 
     user's behavior independently. 
      
     Another requirement related to accounting is the ability to notify 
     a user when accounting really starts.  When a "free preview" 
     capability is supported, accounting may not start at the same time 
     as the user's joining of the stream. 
      
      
  5.1.2.2 Authorization Requirements 
      
    The NSPs are responsible for delivering content and are required to 
    meet certain QoS levels or SLA (service level agreements). For 
    example, video quality is very sensitive to packet loss. So if an 
    NSP cannot meet the quality requirements due to limited network 
    resources if it accepts an additional user request, the NSP should 
    reject that end user's access request to avoid charging the 
    existing (i.e., already joined) user for bad services.  For example, 
    if an access line is shared by several users, an additional user's 
    join may cause performance degradation for other users.  If the 
    incoming user is the first user on an edge node, this will initiate 
    the transmission of data between the multicast router and the edge 
    node and this extra network traffic may cause performance 
    degradation.  There may also be policies that do not necessarily 
    give highest priority to the "first-come" users, and these should 
    also be considered. 
     
   
   
   
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    In order to protect network resources against misuse/malicious 
    access and maintain a QoS level, appropriate admission control 
    function for traffic policing purposes is necessary so that the NSP 
    can accept or reject the request without degrading the QoS beyond 
    the specified level. 
     
     
  5.1.2.3 Authentication Requirements 
      
     There are two different aims of authentication.  One is 
     authentication for network access, and another one is for content 
     access. For the first case of authentication, NSP has a AAA server, 
     and for the second case, each CP has a AAA server. In some cases, 
     CPs delegate (outsource) the operation of user authentication to 
     NSPs. 
      
     As such, in addition to network access, multicast group access by 
     a user also needs to be authenticated.  Content authentication 
     should support the models where: 
          - authentication for multicast content is outsourced to the 
            NSP. 
          - authentication for multicast content access is operated by 
            the content provider 
      
      
  5.2 IP Multicast-based Content Delivery Service (CDS): CP and NSP are 
     the same entities (companies) 
      
     Another application example is the case where the content provider 
     (CP) and network service provider (NSP) are the same entity 
     (company) as shown in Fig. 3.  In the case that the CP and NSP are 
     the same entity, some of the requirements indicated in 4.1 are not 
     required. 
      
     This model does not require the following items: 
      
          - Communication method between sender (server) and user (end 
            host).  Since they belong to the same company, they can use 
            all the available information. 
           
   
   
   
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          - Methods to share user-related information between network 
            providers and content providers. 
       +-----------------------------------------------------+ 
       |              +---------+                            | 
       |              | content |                            | 
       |              | server  |                            | 
       |              +----+----+                            | 
       |                   |                                 | 
       | CP+NSP    +-------+-------+                         | 
       |           | Provider Edge |                         | 
       |           +-------+-------+  +--------------------+ | 
       |                   |          | Information server | | 
       |                   |          +--------------------+ | 
       |           +-------------+                           | 
       |           | User Edge   |                           | 
       |           +--+---+---+--+                           | 
       |             /    |    \                             | 
       +----------- / --- | --- \ ---------------------------+ 
                   /      |      \ 
                  /       |       \ <- user/network interface 
                 /        |        \ 
      +---------++  +-----+----+   ++---------+ 
      |user #a   |  |user #b   |   |user #c   | 
      +----------+  +----------+   +----------+ 
        End user A    End user B     End user C 
       
                 Fig.3 Example of CDS network configuration 
      
      
      
  6. Acknowledgments 
      
     The authors of this draft would like to express their appreciation 
     to Pekka Savola of Netcore Ltd., Daniel Alvarez, and Toerless 
     Eckert of Cisco Systems, Sam Sambasivan of AT&T, Sanjay Wadhwa of 
     Juniper, Tom Anschutz and Steven Wright of BellSouth, Nicolai 
     Leymann of T-Systems, Carlos Garcia Braschi of Telefonica Empresas, 
     Marshall Eubanks of Multicast Techno, Stephen Rife of NTT and 
     David Meyer in his role as mboned WG chair, as well as their 
     thanks to the participants of the MBONED WG in general. 
      
   
   
   
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     Funding for the RFC Editor function is currently provided by the 
     Internet Society. 
   
   
  7. IANA Considerations 
      
     This I-D does not raise any IANA consideration issues. 
      
      
  8. Security Considerations 
      
     Accounting capabilities can be used to enhance the security of 
     multicast networks by excluding ineligible clients from the 
     networks. 
      
      
  9. Conclusion 
      
     This I-D describes general requirements for providing "well 
     managed" IP multicasting services. It lists issues related to 
     accounting, authentication, authorization and admission control 
     for multicast content delivery.  Content Delivery Services with 
     different business models is cited as an application which could 
     benefit from the capabilities of "well managed" IP multicasting 
     described in this document. 
     It is proposed that this document be used as a starting point for 
     discussing requirements for "well managed" IP multicasting 
     services. 
      
      
  Normative References 
      
     [1] B. Cain, et. al., "Internet Group Management Protocol, Version 
         3", RFC3376, October 2002. 
      
     [2] R. Vida, et. al., "Multicast Listener Discovery Version 2 
         (MLDv2) for IPv6", RFC3810, June 2004. 
      
   
   
   
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  Authors' Addresses 
      
             Tsunemasa Hayashi 
             NTT Network Innovation Laboratories 
             1-1 Hikarino'oka, Yokosuka-shi, Kanagawa, 239-0847 Japan 
             Phone: +81 46 859 8790 
             Email: hayashi.tsunemasa@lab.ntt.co.jp 
      
             Haixiang He 
             Nortel 
             600 Technology Park Drive Billerica, MA 01801, USA 
             Phone: +1 978 288 7482 
             Email: haixiang@nortel.com 
      
             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 
             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 
      
             Susheela Vaidya 
             Cisco Systems, Inc. 
             170 W. Tasman Drive San Jose, CA 95134 
             Phone: +1 408 525 1952 
             Email: svaidya@cisco.com 
      
      
      
      
      

      



   
   
   
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