Tsunemasa Hayashi, NTT Internet Draft Haixiang He, Nortel Networks Expires: August 13, 2005 Hiroaki Satou, NTT Hiroshi Ohta, NTT Susheela Vaidya, Cisco Systems February 13 2005 Issues Related to Receiver Access Control in the Current Multicast Protocols Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. 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 become aware will be disclosed, in accordance with RFC 3668. 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 13, 2005 Copyright Notice Copyright (C) The Internet Society (2005) Hayashi, He, Satou, Ohta, Vaidya [Page 1] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 Abstract This I-D lists and describes issues related to receiver access control in current multicasting protocols which are especially important to commercial, large-scale multicasting. A few common business models for content and network provision are presented to provide background and explain the motivation of this work. Four existing possible multicasting architectures (with or without some form of access or content control) are presented. Then each architecture is analyzed with respect to how it can or cannot satisfactorily address each issue. This I-D concludes that for many of these issues the possible architectures based on present standards as they now exist require non-standardized solutions to meet common use requirements. This I-D recommends for requirements to be defined that would set the groundwork for creating standardized ways to overcome these limitations. Copyright Notice...................................................1 1. Introduction....................................................3 2. Definitions and Abbreviations...................................4 2.1 Definitions....................................................4 2.2 Abbreviations..................................................5 3. Common use models and network architecture implications.........5 4. Issues in multicasting related to commercial and large-scale implementations....................................................6 4.1 Access limits and resource issues..............................6 4.1.1 Access limit for multicast groups............................6 4.1.2 Maintain guaranteed quality-level of data delivery (Voice, Video).............................................................7 4.1.3 Issue of network resource protection.........................7 4.1.3.1 Control mechanism to support bandwidth of multicast stream from a physical port of edge router or switch......................7 4.2 Capability to distinguish between receivers (end hosts)........7 4.3 Capability to distinguish between users (as opposed to merely hosts).............................................................8 4.4 Channel "leave latency"........................................8 4.5 Surveillance of receiver by sender.............................9 4.5.1 Precise access log...........................................9 4.5.2 How to share user information................................9 4.5.3 Trustworthy logs to monitor user activity....................9 Hayashi, He, Satou, Ohta, Vaidya [Page 2] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 4.6 Notification to users of the result of the join request.......10 4.7 Triple Play...................................................10 4.8 DRM Protection................................................10 5. Description of existing architectures..........................10 5.1 IGMP/MLD......................................................10 5.2 IGMP/MLD with L2 Authentication with ACL......................11 5.3 Unicast Control with IGMP/MLD.................................12 5.4 IGMP/MLD with Multicast Encryption............................12 6. Evaluation of architectures by issue...........................13 6.1 Access limit capabilities, compared by architecture...........13 6.2 Capability to distinguish between receivers, compared by architecture......................................................14 6.3 Capability to distinguish between users, compared by architecture ..................................................................14 6.4 Maintain guaranteed quality-level of data delivery (Voice, Video), compared by architecture..........................................15 6.5 Fast leave for fast surfing capability, compared by architecture ..................................................................15 6.6 Surveillance of receiver by sender, compared by architecture..16 6.7.Notification to users of the result of the join request compared by architecture...................................................16 6.8 Triple Play capability, compared by architecture..............17 7. IANA considerations............................................17 8. Security considerations........................................17 9. Conclusion.....................................................17 Normative References..............................................18 Full Copyright Statement..........................................19 Intellectual Property.............................................19 Acknowledgement...................................................19 1. Introduction The intention of this I-D is to initiate a discussion on issues related to receiver access control in the current multicast protocols especially when deployed for commercial, large-scale multicasting. It is hoped that further drafts will define requirements to address the issues raised in this draft. Existing IP multicasting protocols (as presented in Section 5) were designed to meet certain sets of requirements that do not necessarily include architectural considerations intended to support commercial services. This I-D presents a number of issues network providers may face when they attempt to apply current multicasting standards to commercial services. The extent to which existing multicast Hayashi, He, Satou, Ohta, Vaidya [Page 3] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 protocols can or cannot satisfactorily deal with issue is explored. A few network models based on a range of different business models are presented as a basis for defining requirements in a future document. 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, 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. This I-D first presents a few common business models for content and network provision in order to provide background and explain the motivation of this work. Then, issues which are important for commercial, large-scale implementations of multicasting are listed. Next, a few possible existing architectures used for multicasting with access control based on current standards are presented. Specifically 1) IGMP/ MLD, 2) IGMP/MLD with L2 Authentication with ACL 3) Unicast Control with IGMP/MLD and 4) IGMP/MLD with Multicast Encryption will each be presented and described. Each architecture is discussed with respect to the presented list of issues. 2. Definitions and Abbreviations 2.1 Definitions For the purposes of this I-D the following definitions apply: Hayashi, He, Satou, Ohta, Vaidya [Page 4] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 Accounting: actions for grasping each user's behavior, when she/he starts/stops to receive a channel, which channel she/he receives, etc. Authentication: action for identifying a user as a genuine one. Authorization: action for giving permission to access the content or network to a user. Receiver: an end-host or end-client which receives content. A receiver may be distinguishable by a network ID such as MAC address or IP address. The receiver should be distinguished from the user (see below.) User: a human with a user account. A user may possibly use multiple reception devices. Multiple users may use the same reception device. 2.2 Abbreviations For the purposes of this draft the following abbreviations apply: ACL: Access Control List CDS: Content Delivery Services CSP: Content Service Provider DRM: Data Rights Management KEI: Key Exchange Identifier NSP: Network Service Provider QoS: Quality of Service 3. Common use models and network architecture implications Issues such as user identification, access-control, tracking and billing are common requirements for commercial content delivery services (CDS) systems (and are important in many non-commercial CDS systems as well.) These same requirements should be met for CDS systems that employ multicasting. In some cases a single entity may design and be responsible for a system that covers the various common high-level requirements of a commercial multicasting system such as 1) content serving, 2) the infrastructure to multicast it, 3) network and content access control mechanisms. Hayashi, He, Satou, Ohta, Vaidya [Page 5] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 However 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 the services from a network service provider and thus share the infrastructure costs with other content holders. Similarly commercial network service providers do not generally 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 business model of a single NSP providing multicasting services to multiple CSP has certain implications: -Need for user tracking and billing capabilities -Need for network access control and/or content access control satisfactory to the requirements of the CSP -Methods for sharing information between the NSP and CSP to make the above two possible When the NSP and CSP 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 In the next section issues in multicasting related to commercial and large-scale implementations are presented. Some presented issues are not pertinent to cases where the NSP and CSP are the same entity. 4. Issues in multicasting related to commercial and large-scale implementations This section lists issues related to receiver access control in current multicasting protocols which are especially important to commercial, large-scale multicasting. 4.1 Access limits and resource issues 4.1.1 Access limit for multicast groups For commercial applications of multicasting network and content providers generally wish to be able to control the number of groups a Hayashi, He, Satou, Ohta, Vaidya [Page 6] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 host can access at the same time. If any user can access any group without limitation network providers may waste network resources, and this may have implications on the Quality of Service (QoS) they can provide to other users. Access control is also important to prevent against unauthorized access of data as it is a priority of many content providers to control access to their content from reasons ranging to IPR issues to privacy issues. 4.1.2 Maintain guaranteed quality-level of data delivery (Voice, Video) For NSP to guarantee and charge for a certain quality of data delivery it is important that they can limit the number of receivers to a level that their bandwidth and servers can handle. With best-effort services (e.g. mail transfer, web surfing) strict network resource allocation is not necessary, but for services with a guaranteed QoS level (e.g. IP television, teleconferencing, VoIP) it is necessary to allocate sufficient bandwidth and server resources to each service. 4.1.3 Issue of network resource protection In order to guarantee certain QoS levels as described in the above section (4.1.2), it is important for network providers to be able to protect their network resources from being wasted, (either maliciously or accidentally). 4.1.3.1 Control mechanism to support bandwidth of multicast stream from a physical port of edge router or switch The network should be able to control the combined bandwidth for all groups both at the physical port of the edge router or switch and on each link between routers and/or NW switches so that these given physical entities are not overflown by the traffic. 4.1.3.2. Number of groups delivered from a physical port of edge router and switch So that the NSP can guarantee a certain level of QoS to the CSP and the receivers it is important that it be able to control the number of groups that are served from any certain edge router or switch at any certain time. When the NSP and the CSP are the same entity the QoS obligations are simplified since guarantees would be made only to the users. 4.2 Capability to distinguish between receivers (end hosts) Currently the sender cannot distinguish which receivers (end hosts) are actually receiving its information with current protocols Hayashi, He, Satou, Ohta, Vaidya [Page 7] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 (IGMP/MLD.) 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. There is currently no standard way to share such information. 4.3 Capability to distinguish between users (as opposed to merely hosts) Many content providers would like to have detailed information on what users are consuming their content and information on their usage behavior. This information might be used for ratings information, billing, auditing, and programming decisions. Also content and network providers may wish to provide users with access to their usage history. If a network provider and content provider are separate entities there are no protocols for sharing such information on a user basis. For example, if NSPs are going to provide access control and/or usage information to a CSP on a user level it is important that the two entities be able to distinguish users and communicate appropriate information. For example, it is quite conceivable that a CSP might want to bill or track separate users who may use the same device (such as at Internet cafes, at hotels, with families, etc.) In such a case it is important that the NSP record information on who is actually downloading data on the user-level since the CSP would otherwise not be able to receive this information. Also for example, in many usage models it is important to provide portability, in other words to allow users to access the network from different devices and/or different access points. If NSPs are going to provide access control and/or billing capability to a separate-entity CSP, this capability of distinguishing users is important. If the same entity is providing both content and network services, the entity has access to sufficient data to distinguish users. Nevertheless a standard way of relaying this information between servers on the network would be attractive from the standpoint of potential decreased development and operational costs. 4.4 Channel "leave latency" Commercial implementations of IP multicasting are likely to have strict requirements in terms of user experience. Leave latency is the time between when a user sends a signal that he/she wishes to "leave" a group and when the network recognizes the "leave." Leave latency impacts : i. Acceptable end-user experience for fast channel surfing. Hayashi, He, Satou, Ohta, Vaidya [Page 8] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 In an IP-TV application, users are not going to be receptive to slow response time when changing channels. ii. Resource consumption With a low "leave latency" network providers could minimize streaming content when there are no audiences. 4.5 Surveillance of receiver by sender 4.5.1 Precise access log In many commercial multicast situations, NSP and CSP would like to be able to precisely grasp the content consumption of end-users. Such information might be used for "identifying highly viewed content" for advertising revenue, ratings calculations, programming decisions, etc. 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. 4.5.2 How to share user information For commercial multicast applications where NSP and CSP are different entities, there are a number of issues regarding how to share user information between the NSP and CSP. For example, which entities should be able to access which information relating to user-based tracking? What is the user identifier that can be used between the entities to distinguish among users, and which entities should be able to recognize this identifier? Another important issue is how the edge router should be able to access and then maintain user information. The current situation of present architectures is that only the NSP can get information about user activity, because user activities are only observable from join/leave information logged on edge devices which are under control of the NSP. 4.5.3 Trustworthy logs to monitor user activity An important issue for commercial multicasting applications is how the NSP can get trustworthy data on user activity which may be needed for billing and statistics purposes. A standard way of logging user activity and protecting the integrity of the logs does not exist. Often network providers do not want to keep logs on untrusted user terminal which can be tampered with. Hayashi, He, Satou, Ohta, Vaidya [Page 9] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 4.6 Notification to users of the result of the join request It is necessary to provide information to the user about the status of his/her join request(granted/denied/other). 4.7 Triple Play 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. 4.8 DRM Protection Digital Rights Management (DRM) is important but out of scope of this I-D. 5. Description of existing architectures In this section, existing architectures used for multicasting based on current standards are defined. In section 6 these architectures will be compared by the issues presented in section 4. 5.1 IGMP/MLD Internet Group Management Protocol(IGMP) or Multicast Listener Discovery (MLD) are protocols for layer 3 management of multicasting. In IP multicast a receiver sends a request to a first-hop multicast router to join a particular multicast group. The router is then responsible for forwarding the appropriate data from the sender to the receiver. +----------+ +----------+ +----------+ +----------+ | Sender | | Router | | L2SW | | Receiver | | | | |<---------------1,JOIN--| | | | | | | | | | | |------------>x------------------2,Data->| | | | | | | | | | | | | | | | | | | | +----------+ +--------|-+ +----------+ +----------+ | V Hayashi, He, Satou, Ohta, Vaidya [Page 10] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 5.2 IGMP/MLD with L2 Authentication with ACL With a basic implementation of IGMP/MLD implementation, no authorization is performed on the receiver. It is possible to combine an IGMP/MLD implementation with Layer 2 Authentication to provide a control mechanism for accessing the network using 802.X. In this scenario a receiver first requests to the L2 authentication server for access to network. The authentication controller then queries the policy server with the receiver's credentials (such as IP or MAC address), and if the receiver is determined to be an authorized user of the network ("success"), the router downloads the ACL from the policy sever. For example, users which are not on the ACL are rejected. Then the Layer 2 Switch is directed to open a port for the receiver to send a join request to the multicast router. The router is then responsible for forwarding the appropriate data from the sender to the receiver. Note: ACL is one of the methods to realize an access control policy. Other methods exist. +----------+ | Policy | | Server |\ | | \ +----------+ \ 4,ACL Download | ^ \ | | \ V | V +----------+ +----------+ +----------+ +----------+ | L2 | | Router | | L2SW | | Receiver | | | | | | | | | | Auth. |<---------------------------- 1,Request-| | | | | | | | | | | |--------2,Success------------>X(3,Auth) | | +----------+ | | | | | | | | | | | | +----------+ | | | | | | | | | |<---------------5,Join---| | | Sender | | | | | | | | |------------>x------------------6,Data-->| | | | | | | | | | | +----------+ +--------|-+ +----------+ +----------+ | V Key: Auth: Authentication Hayashi, He, Satou, Ohta, Vaidya [Page 11] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 5.3 Unicast Control with IGMP/MLD The receiver first sends a unicast request to the sender, if authorization is successful the sender sends the multicast address information via unicast. With this multicast address the receiver does a IGMP\MLD join as in described in 5.1. +----------+ +----------+ +----------+ +----------+ | Sender | | Router | | L2SW | | Receiver | | | | | | | | | | |<------------------------------1,Request-| | | | | | | | | | | |-------------------------------2,Success>| | | | | | | | | | | | | |<--------------3,Join----| | | | | | | | | | | |------------>x-----------------4,Data--->| | | | | | | | | | | | | | | | | | | | +----------+ +--------|-+ +----------+ +----------+ | V 5.4 IGMP/MLD with Multicast Encryption With a basic implementation of IGMP/MLD implementation, no data protection is performed on data sent to the receiver. No credential check is performed on the receiver and any receiver can receive and use the data. The IGMP/MLD with Multicast Encryption model assumes that the sender is sending encrypted data and that for this data to be useful to the receiver it must first request and receive a key from a group controller and key server that is synchronized with the content encryption occurring on the sender's data. Hayashi, He, Satou, Ohta, Vaidya [Page 12] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 +----------+ +----------+ +----------+ +----------+ | G.C. & | | Router | | L2SW | | Receiver | | | | | | | | | | Key S. |<------------------------------1,Request-| | | | | | | | | | | |-------------------------------2,Key---->| | +----------+ | | | | | | | | | | | | +----------+ | | | | | | | | | |<---------------3,Join---| | | Sender | | | | | | | | |------------>x------------------4,Data-->| | | | | | | | | | | +----------+ +--------|-+ +----------+ +----------+ | V Key: G.C. & Key S.= Group Controller and Key Server 6. Evaluation of architectures by issue In this section the various issues raised in section four are analyzed by each of the architectures introduced in section five. 6.1 Access limit capabilities, compared by architecture Comparison of currently available architectures with respect to limiting the access of multicast groups - IGMP/MLD: It is not possible to limit data reception. - L2 authentication with ACL: With an ACL it is possible to limit access of multicast groups. However it should be discussed as to how scalable this approach is because configuring an ACL could be a labor-intensive task. - IGMP/MLD with Unicast control It is possible for malicious users to reconfigure the receiver's terminal to ignore the Unicast control. As such, this method may not be strong enough to exclude ineligible accesses. -Multicast Encryption: It is possible for receivers to receive IP packets, even if they do not possess the keys to decrypt them. A receiver may also be able to store such received data until they discover a way to decrypt it. Another disadvantage of this method is that network resources are Hayashi, He, Satou, Ohta, Vaidya [Page 13] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 wasted if an ineligible receiver receives an encrypted content even if they do not have a valid key. 6.2 Capability to distinguish between receivers, compared by architecture Comparison of currently available protocols. -IGMP/MLD: The sender has no direct line of contact with the receiver and therefore cannot distinguish on a receiver-basis. (If the interface is fixed to the receiver then the join-log can be used, but this would mean portability is sacrificed. Moreover, this method is not applicable to a case where the CSP and NSP are different companies because CSP cannot access this join-log.) -L2 authentication with ACL: At the moment of L2 authentication it is possible to recognize receivers, but if there are multiple content service providers (CSP) a single L2 Authorization Server cannot distinguish among the CSPs. Therefore it would be necessary to gather the join logs. (If the interface is fixed then the join-log can be used, but this would mean portability is sacrificed. Moreover, this method is not applicable to a case where the CSP and NSP are different companies because the CSP cannot access this join-log.) -IGMP/MLD with Unicast control : It is possible to distinguish among receivers using Unicast control. -Multicast Encryption: If the Content Service Provider maintains the Key Server it is possible to distinguish on the receiver-level. If the Network Service Provider maintains the key server it is necessary to devise a method for the NSP to notify the CSP. 6.3 Capability to distinguish between users, compared by architecture Comparison of currently available protocols: -IGMP/MLD: Since there is no user-based information, it is not possible to distinguish on the user-level. -L2 authentication with ACL: At the moment of L2 Authentication it is possible to distinguish on the user-level. Hayashi, He, Satou, Ohta, Vaidya [Page 14] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 However it is difficult to combine user and group logs: it would be necessary to match user IDs from L2-Auth logs and group IDs from the Join logs to match users and groups. -IGMP/MLD with unicast control : Distinguishing by user is possible using unicast control. -Multicast Encryption: If the Content Provider manages the Key Server it is possible to distinguish the user. If the Network Service Provider manages the Key Server it is necessary to notify the Content Provider. 6.4 Maintain guaranteed quality-level of data delivery (Voice, Video), compared by architecture Comparison of currently available protocols: -IGMP/MLD: It is not possible to reject a user attempting to access even if there are not sufficient resources. -L2 authentication with ACL: The AAA server does not know whether there are sufficient resources or not. While it is possible to control QoS levels on a link-by-link basis, it is not possible on a service-by-service basis. -IGMP/MLD with Unicast control : When the CSP and NSP are separate entities it is not possible for the CSP to make a proper authorization decision because only the NSP grasps the network resource availability. -Multicast Encryption: It is not possible to reject a user attempting to access even if there are not sufficient resources because the user can receive data even without a valid key. 6.5 Fast leave for fast surfing capability, compared by architecture Comparison of currently available protocols: -IGMP/MLD: It is possible to track on a per host level (based on host address) therefore fast leave for fast surfing capability can be achieved. -L2 authentication with ACL: Hayashi, He, Satou, Ohta, Vaidya [Page 15] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 It is possible to track on a per host level (based on host address) therefore fast leave for fast surfing capability can be achieved. -IGMP/MLD with Unicast control : Even if a quick leave is possible, changing to a new channel using Unicast Control is slow (latency problem). -Multicast Encryption: Even if a quick leave is possible, delivery of the Key Exchange Identifier(KEI) is slow. 6.6 Surveillance of receiver by sender, compared by architecture Comparison of currently available protocols: -IGMP/MLD: With this protocol it is possible to log separately join and leave actions, but it is difficult to match these join and leave actions when analyzing the logs is heavy computation (scalability with millions of users). -L2 authentication with ACL: In this protocol the leave action is not recorded. -IGMP/MLD with Unicast control : In this solution the leave action is not recorded. -Multicast Encryption: If logs are recorded for each renewal of keys, then it is possible to track activity on a per-user basis. However if logs are only recorded per content data download then such tracking is not possible. 6.7.Notification to users of the result of the join request compared by architecture Comparison of currently available protocols: -IGMP/MLD: After the join it is not possible to notify the user of the result of the join request. -L2 authentication with ACL: After the join it is not possible to notify the user of the result of the join request. -IGMP/MLD with Unicast control : After the join it is not possible to notify the user of the result of the join request. Hayashi, He, Satou, Ohta, Vaidya [Page 16] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 -Multicast Encryption: After the join it is not possible to notify the user of the result of the join request. 6.8 Triple Play capability, compared by architecture Comparison of currently available protocols: -IGMP/MLD: It is necessary for NSP to integrate all "triple play services" into a single access control system. No standards currently exist. -L2 authentication with ACL: When services have a per-channel fee structure that require real-time changes to the access control list (such as prepayment for specific shows), it is not possible to integrate these services with other services. On the other hand for a fixed subscription based service where the access control list is not changed, it is possible to integrate the triple-play services on one infrastructure. -IGMP/MLD with Unicast control : It is necessary for NSP to integrate all "triple play services" into a single access control system. No standards currently exist. -Multicast Encryption: It is necessary for NSP to integrate all "triple play services" into a single access control system. No standards currently exist. 7. IANA considerations This I-D does not raise any IANA consideration issues. 8. Security considerations This I-D does not raise any new security issues which are not already existing in original protocols. Enhancement of multicast access control capabilities may enhance security performance. 9. Conclusion Issues such as user identification, access-control, tracking and billing are common requirements for many content delivery services (CDS) systems. When CDS systems employ multicasting with architectures based on currently existing multicasting standards, it is often necessary to deploy non-standardized solutions to meet these Hayashi, He, Satou, Ohta, Vaidya [Page 17] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 common requirements. It is recommended that requirements be defined to serve as a basis for creating standardized ways to address the various issues discussed in this I-D which are limiting the application of multicasting especially to commercial, large-scale CDS services. Such requirements should take into consideration a range of possible architectures based on multiple business or usage models. 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. Authors' Addresses Tsunemasa Hayashi NTT Network Innovation Laboratories 1-1 Hikari-no-oka, Yokosuka-shi, Kanagawa, 239-0847 Japan Phone: +81 46 859 8790 Email: hayashi.tsunemasa@lab.ntt.co.jp Haixiang He Nortel Networks 600 Technology Park Drive Billerica, MA 01801, USA Phone: +1 978 288 7482 Email: haixiang@nortelnetworks.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 Hayashi, He, Satou, Ohta, Vaidya [Page 18] Internet Draft draft-hayashi-rac-issues-00.txt February, 2005 Full Copyright Statement Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf ipr@ietf.org. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Hayashi, He, Satou, Ohta, Vaidya [Page 19]