Tsunemasa Hayashi, NTT Internet Draft Haixiang He, Nortel Networks Expires: October 21, 2006 Hiroaki Satou, NTT Hiroshi Ohta, NTT Susheela Vaidya, Cisco Systems April 19, 2006 Issues Related to Receiver Access Control in the Current Multicast Protocols 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 October 21, 2006. Copyright Notice Copyright (C) The Internet Society (2006) Hayashi, He, Satou, Ohta and Vaidya [Page 1] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 Abstract This memo evaluates the extent to which current multicasting protocols can be used to address common requirements for commercial, large-scale IP multicasting, but may be applicable to non-commercial deployments as well. 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 memo 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 memo recommends for requirements to be defined that would set the groundwork for framework(s) and solutions that sufficiently address 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....................................................7 4.1 Access limits and resource issues..............................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 Minimizing Channel Join Latency and Leave Latency..............8 4.5 Surveillance of receiver by sender.............................8 4.5.1 Precise access logging.......................................8 4.5.2 How to share user information................................8 4.5.3 Trustworthy logs to monitor user activity....................9 4.6 Notification to users of the result of the join request........9 4.7 Sharing of Infrastructure for Support of Triple Play Services..9 4.8 DRM Protection.................................................9 5. Description of existing architectures...........................9 5.1 IGMP/MLD......................................................10 5.2 IGMP/MLD plus L2/L3 Authentication with Access Control Policy.11 5.3 Unicast Control with IGMP/MLD.................................13 5.4 IGMP/MLD with Multicast Encryption............................13 6. Evaluation of architectures by issue...........................14 6.1 Access limit capabilities, compared by architecture...........14 Hayashi, He, Satou, Ohta, Vaidya [Page 2] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 6.2 Capability to distinguish between receivers, compared by architecture......................................................15 6.3 Capability to distinguish between users, compared by architecture......................................................16 6.4 Maintain guaranteed quality-level of data delivery (Voice, Video), compared by architecture..................................17 6.5 Fast leave for fast surfing capability, compared by architecture ..................................................................17 6.6 Surveillance of receiver by sender, compared by architecture..18 6.7 Notification to users of the result of the join request compared by architecture...................................................19 6.8 Comparison summary............................................19 7. Relevance to non-commercial deployments........................20 8. IANA considerations............................................20 9. Security considerations........................................20 10. Conclusion....................................................20 Normative References..............................................21 Comments..........................................................22 Full Copyright Statement..........................................23 Intellectual Property.............................................23 Expiration........................................................24 Acknowledgement...................................................24 1. Introduction The intention of this memo is to initiate a discussion on the state of current multicasting protocols deployed for commercial, large- scale multicasting and their capabilities to provide receiver access control. Many of the issues discussed in this memo may be relevant to non-commercial situations, as well. 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 memo 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 protocols can or cannot satisfactorily deal with these Hayashi, He, Satou, Ohta, Vaidya [Page 3] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 issues is explored. A few network models based on a range of different business models are presented as a basis for defining requirements. 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 in terms of its commercial applicability because of the insufficiency of access control and protection of network resources against malicious use or accidents. In order to be applicable to large-scale commercial networks, multicast networks need to have the same capabilities which are currently supported by unicast networks. Such issues which are important to 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/L3 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 memo the following definitions apply: 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. Hayashi, He, Satou, Ohta, Vaidya [Page 4] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 Triple Play: voice (VoIP), video, and broadband Internet access services. 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 purposes of this draft the following abbreviations apply: ACL: Access Control List CDS: Content Delivery Services CP: Content 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 Hayashi, He, Satou, Ohta, Vaidya [Page 5] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 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 memo draft-ietf-mboned-maccnt-04.txt [3, referred to hereafter in this memo as MACCNT-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 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 network service provider (NSP) providing multicasting services to multiple content providers CP 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 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 Hayashi, He, Satou, Ohta, Vaidya [Page 6] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 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 CP 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. To avoid unnecessary duplication with MACCNT-draft, detail for some of these issues is provided through references in the Normative Reference section. 4.1 Access limits and resource issues For commercial applications of multicasting, network and content providers generally wish to be able to control the number of groups a host can access at the same time. Also the network provider may wish to limit the number of users accessing a multicast stream because of bandwidth and processing issues between the receiver and the multicast server. This section corresponds to MACCNT-draft[3], section 4.5.14.2 "Issue of network resource protection", and 4.2.1 "Access control", but provides more detail. 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. More detail on the topic of network resource protection is provided in section "Issue of network resource protection" of the MACCNT-draft[3]. 4.2 Capability to distinguish between receivers (end hosts) For detail on the topic on the capability to distinguish between receivers, refer to MACCNT-draft[3], 4.1 the second paragraph which Hayashi, He, Satou, Ohta, Vaidya [Page 7] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 begins with "With current protocols (IGMP/MLD), the sender cannot distinguish 4.3 Capability to distinguish between users (as opposed to merely hosts) Detail related to the topic of user identification can be found in section "User identification" of the MACCNT-draft[3], the first paragraph. 4.4 Minimizing Channel Join Latency and Leave Latency More detail on the topic of channel leave latency is provided in section "Channel Join Latency and Leave Latency" of the MACCNT- draft[3]. 4.5 Surveillance of receiver by sender 4.5.1 Precise access logging For detail on the topic please refer to MACCNT-draft[3], 4.6 "Accounting and billing", especially the second paragraph which begins with " To assemble such..." 4.5.2 How to share user information For commercial multicast applications where NSP and CP are different entities, there are a number of issues regarding how to share user information between the NSP and CP. 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. This section Hayashi, He, Satou, Ohta, Vaidya [Page 8] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 corresponds to MACCNT-draft[3], section 4.5.1 "How to share user information", but provides more detail than in the MACCNT-draft. 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 terminals that can be tampered with. 4.6 Notification to users of the result of the join request Details for this issue are presented in MACCNT-draft[3], section 4.6 "Notification to users of the result of the join request." 4.7 Sharing of Infrastructure for Support of Triple Play Services As stated in MACCNT-draft[3], section "Small impact on the existing products": "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". 4.8 DRM Protection Digital Rights Management (DRM) is important but out of scope of this memo. 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. Hayashi, He, Satou, Ohta, Vaidya [Page 9] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 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--| | | | | | | | | | | |--------------------------------2,Data->| | | | | | | | | | | | | | | | | | +----------+ +----------+ +----------+ +----------+ For the sake of simplicity, the above diagram only shows the sequence of requests for a single receiver. When multiple receivers are requesting the same channel stream the data would be copied at the multicasting router to serve the multiple streams. Hayashi, He, Satou, Ohta, Vaidya [Page 10] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 5.2 IGMP/MLD plus L2/L3 Authentication with Access Control Policy With a basic implementation of IGMP/MLD, no authorization is performed on the receiver. It is possible to combine an IGMP/MLD implementation with Layer 2 or Layer 3 Authentication to provide an access-control mechanism at the first point of attachment to the network, for example, using 802.1X. For example, a receiver may request to an L2 authentication server for access to the 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 server. 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 existing method 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 | | | | | | | Hayashi, He, Satou, Ohta, Vaidya [Page 11] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 | |------------>x------------------6,Data-->| | | | | | | | | | | +----------+ +--------|-+ +----------+ +----------+ | V Key: Auth: Authentication Hayashi, He, Satou, Ohta, Vaidya [Page 12] Internet Draft draft-ietf-mboned-rac-issues-01.txt March, 2006 5.3 Unicast Control with IGMP/MLD The receiver first sends a unicast request to the sender which resides in the CP's domain. This method is the same as that used in unicast video-on-demand (VoD) systems. 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. Generally this approach is relying on either some sort of content encryption or "security through obscurity" for content security. Also accounting becomes problematic because user credentials may not be identified. +----------+ +----------+ +----------+ +----------+ | 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, 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 13] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 +----------+ +----------+ +----------+ +----------+ | 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/L3 authentication with access control policy: 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. In this case, this Hayashi, He, Satou, Ohta, Vaidya [Page 14] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 maliciously reconfigured terminal could send a join message even if it is rejected by the network. In such a case, the ineligible receiver would be able to receive the multicast. As such, this method may not be strong enough to exclude ineligible access. -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 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 possible protocol-based solutions. -IGMP/MLD: The sender has no direct line of contact with the receiver and therefore cannot distinguish on a receiver-basis. (If the edge- router's user interface is statically assigned then the interface's log can be used to track joins, but this would mean portability is sacrificed. Moreover, this method is not applicable to a case where the CP and NSP are different companies because the CP cannot access this join-log. Sharing of the join-log could be done with a yet-to- be defined standard mechanism/format. ) -L2/L3 authentication with access control policy: At the moment of L2/L3 authentication it is possible to recognize receivers, but if there are multiple content providers (CP) a single L2 Authorization Server cannot distinguish among the CPs. 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 CP and NSP are different companies because the CP cannot access this join-log.) -IGMP/MLD with Unicast control : Hayashi, He, Satou, Ohta, Vaidya [Page 15] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 It is possible to distinguish among receivers using Unicast control. This latency may not be a problem when users are switching between channels of the same CP in cases where the CP grants viewing privileges uniformly across all of its channels. However, other policies are possible that may be on a channel-basis, time-basis, etc. and in such cases channel changing has latency issues. -Multicast Encryption: If the CP 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 CP. 6.3 Capability to distinguish between users, compared by architecture Comparison of currently possible protocol-based solutions: -IGMP/MLD: Since there is no user-based information, it is not possible to distinguish on the user-level. -L2/L3 authentication with access control policy: At the moment of L2/L3 Authentication it is possible to distinguish on the user-level. 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. Hayashi, He, Satou, Ohta, Vaidya [Page 16] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 6.4 Maintain guaranteed quality-level of data delivery (Voice, Video), compared by architecture Comparison of currently possible protocol-based solutions: -IGMP/MLD: It is not possible to reject a user attempting to access even if there are not sufficient resources. -L2/L3 authentication with access control policy: The AAA server does not know whether there are sufficient resources or not. This method still can provide a guaranteed QoS if every channel has the same bandwidth and sufficient bandwidth are allocated to each user beforehand. However, it is not possible to provide a guaranteed QoS by comparing the available bandwidth and the necessary bandwidth upon each user's request. -IGMP/MLD with Unicast control: When the CP and NSP are separate entities it is not possible for the CP to make a proper authorization decision because only the NSP grasps the network resource availability. -Multicast Encryption: Having only encryption provides no access control and therefore provides no mechanism to reject a user attempt to access when sufficient resources are not available (i.e. the user can receive data even without holding a valid key.) 6.5 Fast leave for fast surfing capability, compared by architecture Comparison of currently possible protocol-based solutions: -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/L3 authentication with access control policy: It is possible to track on a per host level (based on host address) therefore fast leave for fast surfing capability can be achieved. Hayashi, He, Satou, Ohta, Vaidya [Page 17] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 -IGMP/MLD with Unicast control : Even if a quick leave is possible, changing to a new channel using Unicast Control is slow (latency problem). This latency may not be a problem when users are switching between channels of the same CP in cases where the CP grants viewing privileges uniformly across all of its channels. However, other policies are possible that may be on a channel-basis, time-basis, etc. and in such cases channel changing has latency issues. -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 possible protocol-based solutions: -IGMP/MLD: With this protocol it is possible to separately log join and leave actions, but it is difficult to match these join and leave actions because analyzing the logs requires heavy computation (related to the scalability with millions of users). -L2/L3 authentication with access control policy: In this solution, the leave action is not recorded unless some additional mechanism such as IGMP/MLD snooping is used. In some cases, users disconnect their terminals without sending logout messages. Also it is possible that the user is running multiple services and thus they will not log out even if they are finished watching video or other multicast content. In this case, it is not possible to precisely determine for accounting purposes when each user disconnected. Also, it may be a problem that unused bandwidth is being needlessly reserved. However MLD/IGMP reports/joins need to be refreshed periodically. The ACL entry can be deactivated if the user no longer refreshes the report/join, but this means that user can be charged with unwatched programs (125 seconds default.) This lack of precise timing may be a problem in certain cases such as for paid services. Hayashi, He, Satou, Ohta, Vaidya [Page 18] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 -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. It should be noted that authentication of the source of each join/leave message is important. 6.7 Notification to users of the result of the join request compared by architecture Comparison of currently possible protocol-based solutions: -IGMP/MLD: After the join it is not possible to notify the user of the result of the join request. -L2/L3 authentication with access control policy: 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. -Multicast Encryption: After the join it is not possible to notify the user of the result of the join request. 6.8 Comparison summary In this section a variety of existing architectures used for multicasting based on current standards were compared and evaluated. Hayashi, He, Satou, Ohta, Vaidya [Page 19] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 None of these architectures can sufficiently meet all of the common requirements for accounting, authentication and authorization in commercial, large-scale IP multicasting. Therefore it is recommended that framework(s) for sufficiently addressing such requirements be explored. 7. Relevance to non-commercial deployments While the impetus for this memo was to discuss issues related to the state of current multicasting protocols deployed for commercial, large-scale multicasting and their capabilities to provide receiver access control. Many of the issues discussed in this memo may be relevant to non-commercial situations, as well. 8. IANA considerations This memo does not raise any IANA consideration issues. 9. Security considerations This memo 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. 10. 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 common requirements. It is recommended that requirements be defined to set the groundwork for creating framework(s) and solutions that address the various issues discussed in this memo 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. Hayashi, He, Satou, Ohta, Vaidya [Page 20] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 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. [3] 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 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 Hayashi, He, Satou, Ohta, Vaidya [Page 21] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 Cisco Systems, Inc. 170 W. Tasman Drive San Jose, CA 95134 Phone: +1-408-525-1952 Email: svaidya@cisco.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. Hayashi, He, Satou, Ohta, Vaidya [Page 22] Internet Draft draft-ietf-mboned-rac-issues-03.txt April, 2006 Full Copyright Statement Copyright (C) The Internet Society (2006). 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. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. 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. Hayashi, He, Satou, Ohta, Vaidya [Page 23] Internet Draft draft-ietf-mboned-rac-issues-03.txt Aprilh, 2006 Expiration This Internet-Draft will expire on October 21, 2006. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Hayashi, He, Satou, Ohta, Vaidya [Page 24]