Multimob Hong-Ke Zhang Internet Draft Jian-Feng Guan Expires: March 2009 Hua-Chun Zhou Zhi-Wei Yan Beijing Jiao Tong University September 30, 2008 MLD Source Address Selection for Mobile Multicast draft-zhang-multimob-mldsas-mmcast-00.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 March 30, 2009. Abstract With the development of wireless and mobile technologies, mobile multicast becomes a research hotspot. However, the current multicast routing protocols can not provide the mobile multicast services. To support the mobile multicast, the related multicast specifications need to be extended. In this memo, we focus on the group membership management protocol and define the new source address selection policy for mobile multicast. Zhang, et al. Expires March 30, 2009 [Page 1] Internet-Draft MLD Source Address Selection September 2008 Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [1]. Table of Contents 1. Introduction.................................................2 2. Terminology..................................................3 3. Justification................................................3 4. Source Address Selection for Mobile Multicast................3 5. Security Considerations......................................4 6. Acknowledgments..............................................4 7. References...................................................5 7.1. Normative References....................................5 7.2. Informative References..................................5 Author's Addresses..............................................6 Intellectual Property Statement.................................6 Copyright Statement.............................................7 Acknowledgment..................................................7 1. Introduction MLD is a subset of ICMPv6 and the message types in MLDv1 [3] and MLDv2 [4] are 130, 131, 132 and 143. All the MLD messages use the link-local address as the source address, and set the hop limit to be 1. Besides, to force the IPv6 routers on that link to check the MLD messages, all the MLD messages are encapsulated in the hop-by-hop option with router alert option [5]. MLD is an asymmetric protocol which consists of the router function and the host function. The router function is used to set up the multicast states for subscribers, while the host function is used by subscribers to send the multicast join and leave messages, and to respond to periodic query messages. However, the current MLD specifications are designed to maintain the dynamic group membership for the fixed nodes. If the MLD protocol is directly used in mobile multicast services, it may cause a long multicast service disruption. According to the MLD specifications, this disruption may be 67 seconds even without the link layer handover and IP layer handover delay [8]. To improve the performance of mobile multicast, some mobile multicast management protocol mechanism has been proposed to manage the mobile subscribers. H. Liu Zhang et al. Expires March 30, 2009 [Page 2] Internet-Draft MLD Source Address Selection September 2008 and H. Asaeda [9] discussed the requirements about the deployment of IGMP/MLD protocols for mobile multicast services. Besides, H. Asaeda and T. C. Schmidt [10] modified the IGMP/MLD and introduced an optional Listener Hold function to support the mobile hosts. Recently, Guan et al. [11] proposed the extended MLD protocol to provide the mobile multicast management for mobile subscribers. However, using the MLD protocols as the multicast membership management in mobile environments conflicts with the source address selection policy in MIPv6 [6]. The MLD specifications mandate the use of a link-local IPv6 source address or the unspecified address (::) [7] for the MLD message. However, the MIPv6 suggests that the mobile node should use the HoA when mobile node transmits the multicast packets through the bi-directional tunnel, and uses the CoA when transmit the multicast packets through the current foreign networks. This memo will extend the IPv6 source address selection rules for use with MLD protocols in mobile multicast services. 2. Terminology The terminology used in this memo is already defined in MLDv1 [3] and MLDv2 [4]. 3. Justification The MLD specifications require that all MLD messages be sent with a valid link-local IPv6 source address. This design principle can restrict group management messages in local link to prevent the diffusion of group membership, which is benefit to reduce the redundant information in the networks. However, it is unable to provide the multicast management for mobile subscribers. To provide the mobile multicast services for mobile subscribers, the MLD protocols need some extensions to manage the mobile multicast states such as the multi-hop extensions in [11]. The foundational problem is how to set up and maintain the multicast states for mobile subscribers. As discussed above, using the traditional MLD specifications will result in a long disruption time and conflict with the mobility specifications. This memo tries to solve these problems by extending a new policy about the source address selection. 4. Source Address Selection for Mobile Multicast To mark the multicast states for mobile subscribers, MLD Report and Done message SHOULD be sent with a valid global unicast IPv6 address Zhang et al. Expires March 30, 2009 [Page 3] Internet-Draft MLD Source Address Selection September 2008 as the IPv6 source address. As for the MLD Report message, some extensions SHOULD be added to carry the location information, Identifier information and group information of mobile subscribers according to [11]. Routers receiving an MLD Report or Done message with the global IPv6 address as the IPv6 source address MUST perform the extended MLD function shown in [11]. The extension of MLD source address selection is used to distinguish the fixed node and mobile node, and provides the necessary information for mobile subscribers. 5. Security Considerations The related security issues are discussed in MLDv1 [3] and MLDv2 [4]. 6. Acknowledgments The authors would like to thank Si-Dong Zhang, Ya-juan Qin, Hongbin Luo (BJTU NGIRC) for their valuable comments and suggestions on this memo. Zhang et al. Expires March 30, 2009 [Page 4] Internet-Draft MLD Source Address Selection September 2008 7. References 7.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, Internet Mail Consortium and Demon Internet Ltd., November 1997. [3] S. Deering, W. Fenner, B. Haberman, "Multicast Listener Discovery (MLD) for IPv6", IETF RFC 2710, 1999. [4] R. Vida and L. Costa, "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", IETF RFC 3810, 2004. [5] C. Partridge, A. Jackson, "IPv6 Router Alert Option", IETF RFC 2711, 1999. [6] D. Johnson, C. Perkins, J. Arkko, "Mobility Support in IPv6", IETF 3775, 2004. [7] B. Haberman, "Source Address Selection for the Multicast Listener Discovery (MLD) Protocol", IETF 3590, 2003. 7.2. Informative References [8] Wu Qian, "Studies on IP Multicast in Mobile Internet" [Ph.D Thesis], Beijing: Tsinghua University, 2006 (in Chinese with English abstract). [9] H. Liu and H. Asaeda, "Mobile Multicast Requirements on IGMP/MLD Protocols", draft-liu-multimob-igmp-mld-mobility-req- 00, November, 2007. [10] H. Asaeda and T. C. Hamburg, "IGMP and MLD Extensions for Mobile Hosts and Routers", draft-asaeda-multimob-igmp-mld- mobility-extensions-01, July, 2008. [11] Jian-feng Guan, Hua-chun zhou, Hong-ke Zhang et al., "MLD Extensions to Support the Mobile Multicast Group management", draft-zhang-multimob-mld-mmcast-00.txt, July, 2008. Zhang et al. Expires March 30, 2009 [Page 5] Internet-Draft MLD Source Address Selection September 2008 Author's Addresses Hong-ke Zhang, Jian-feng Guan, Hua-chun Zhou, Zhi-wei Yan Next Generation Internet Research Center (NGIRC), Beijing JiaoTong University Beijing, China, 100044 Phone: +86 10 51685677 Email: hkzhang@bjtu.edu.cn guanjian863@163.com hchzhou@bjtu.edu.cn 06120232@bjtu.edu.cn Intellectual Property Statement 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. Zhang et al. Expires March 30, 2009 [Page 6] Internet-Draft MLD Source Address Selection September 2008 Copyright Statement Copyright (C) The IETF Trust (2008). 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, THE IETF TRUST 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." Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Zhang et al. Expires March 30, 2009 [Page 7]