Network Working Group S. Jeong Internet-Draft ETRI Expires: December 28, 2006 H. Jang SAIT June 26, 2006 IPv6 Multicast Packet Delivery over IEEE 802.16 Networks draft-jeong-16ng-multicast-delivery-01 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 December 28, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This memo describes the transmission of IPv6 multicast packets over IEEE 802.16 networks, including methods to deliver various scoped multicast packets. It also presents a method of forming multicast CIDs on IEEE 802.16 networks. Jeong & Jang Expires December 28, 2006 [Page 1] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Assumption and Scope . . . . . . . . . . . . . . . . . . . 3 1.2. Terminology and Abbreviations . . . . . . . . . . . . . . 4 2. Brief Description of Subnet Models . . . . . . . . . . . . . . 5 3. Subnet Model A . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 6 3.2. Multicast Packet from AR or Other Subnets . . . . . . . . 6 4. Subnet Model B . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 8 4.2. Multicast Packet from AR or Other Subnets . . . . . . . . 8 5. Subnet Model C . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 9 5.2. Multicast Packet from BS/AR or Other Subnets . . . . . . . 9 6. Subnet Model D . . . . . . . . . . . . . . . . . . . . . . . . 10 6.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 10 6.2. Multicast Packet from BS/AR or Other Subnets . . . . . . . 10 7. Considerations about mCID Format . . . . . . . . . . . . . . . 11 7.1. IPv6 scope-based mCID Format . . . . . . . . . . . . . . . 11 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Intellectual Property and Copyright Statements . . . . . . . . . . 15 Jeong & Jang Expires December 28, 2006 [Page 2] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 1. Introduction IEEE 802.16 networks support mobile stations (MSs) to access broadband wireless networks while moving at vehicular speed [IEEE802.16e]. However, IEEE 802.16 networks do not provide link layer native multicast capability because of point-to-multipoint connection characteristic [IEEE802.16]. This feature restricts the adoption of protocols or applications that need IPv6 multicast capability. One of the prominent ways to solve the multicast support problem is to use the built-in LAN emulation feature of IEEE 802.16 which is based on Convergence Sublayer [I-D.jee-16ng-ps-goals]. There is several previous work which was focused on the transport of link local scope multicast packets over IEEE 802.16 network [I-D.jeon-ipv6-ndp-ieee802.16] [I-D.jang-16ng-llm]. However, the IPv6 multicast service requires not only the delivery of link local scope multicast packets, but also the delivery of non-link local scope multicast packets such as site local or global scope multicast packets. Since it is not clear that which subnet models would be used in IEEE 802.16 networks, we consider the transport of IPv6 multicast packets over various subnet models proposed in [I-D.ietf- v6ops-802-16-deployment-scenarios]. This memo describes how the IPv6 multicast packets with various scope can be delivered over four different types of subnet models. 1.1. Assumption and Scope This document describes how to provide IPv6 CS based IPv6 multicast packets delivery over IEEE 802.16 networks. We will consider Ethernet CS based IPv6 multicast packet transport in the later version of this document. We classify the IPv6 multicast packet into link local scope and non- link local scope multicast packet. Node-local scope multicast packet is not considered in this memo. When a BS is separated from an access router (AR), we assume that the BS is connected to the AR via Ethernet. If Ethernet is not used between the BS and the AR, tunneling may be used to apply our proposed approaches. Our approaches are based on the use of multicast CID (mCID) to distinguish between multicast and unicast packets, and to deliver the multicast packets. This memo presents mCID based transport of IPv6 multicast packet not only link local scope, but also non-link local scope. The initialization or distribution of mCID is not covered in this document, but we may guess that the mCID will be initialized during the establishment phase of host IPv6 connectivity. Jeong & Jang Expires December 28, 2006 [Page 3] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 1.2. Terminology and Abbreviations In this memo, a link local multicast packet indicates a multicast packet with link local scope such as NS, RA, and so on. A non-link local multicast packet means that the scope of the packet is neither node local nor link local. The non-link local multicast packet also includes a multicast data packet. Terminology in this document follows that in [I-D.jee-16ng-ps-goals], with the addition of a new terminology given here: o mCID (multicast CID) : CID for IPv6 multicast packet transport Jeong & Jang Expires December 28, 2006 [Page 4] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 2. Brief Description of Subnet Models The relationship between a BS and an AR induces several IPv6 subnet models in IEEE 802.16 networks. This document describes the transport of IPv6 multicast packets with IPv6 CS over each subnet models proposed in [I-D.ietf-v6ops-802-16-deployment-scenarios]. We may deduce following four IPv6 subnet models from the IPv6 prefix assignment methods and the relationship between the AR and the BS. +--------+---------------------------+----------------------------+ | Subnet | Deployment architecture | Subnet components | | model | | | +--------+---------------------------+----------------------------+ | A | BS is separated from AR | single AR, multiple BSs, | | | | multiple MSs | +--------+---------------------------+----------------------------+ | B | BS is separated from AR | multiple BSs, multiple MSs | +--------+---------------------------+----------------------------+ | C | BS is integrated with AR | single BS/AR, multiple MSs | +--------+---------------------------+----------------------------+ | D | BS is integrated with AR | single BS/AR, single MS | +--------+---------------------------+----------------------------+ Figure 1: IPv6 subnet models in IEEE 802.16 networks Jeong & Jang Expires December 28, 2006 [Page 5] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 3. Subnet Model A In this section, we discuss the transport of IPv6 multicast packets over the 'Subnet Model A' shown in Figure 2 where a BS is separated from an AR and a subnet consists of single AR, multiple BSs, and multiple MSs. This scenario covers the current celluar-like deployment models such as WiMax and WiBro. +-----+ | MS1 |------+ +-----+ | +-----+ | +-----+ | MS2 |<------+----| BS1 |---+ +-----+ +-----+ | +-----+ +--------+ |--->| AR |----| Edge | ISP | +-----+ | Router +==>Network +-----+ +-----+ | +--------+ | MS3 |<-----------| BS2 |---+ +-----+ +-----+ <---> IP termination Figure 2: Subnet Model A 3.1. Multicast Packet from MS In the Figure 2, when the BS1 receives a multicast packet which was originated from the MS1, the BS1 multicasts the packet onto its downlinks by using mCID. After then, BS1 converts the IEEE 802.16 MAC frame format to IEEE 802.3 Ethernet frame and transmits the frame into the link connected to the AR. The BS2 which is on the same link as the BS1, receives the IEEE 802.3 Ethernet frame sent from the BS1 and examines the IPv6 destination address. If the destination address is a multicast address, the BS2 multicasts the received packet to its downlinks with predefined mCID. When the AR receives the IPv6 multicast packet transmitted by BS1, it investigates the scope of the IPv6 multicast destination address. If the multicast packet is destined to itself (i.e., link local scope multicast packet), the AR processes the multicast packet. If the multicast packet has non-link local scope, the AR performs the multicast routing table lookup and forwards the received multicast packet according to the lookup result. 3.2. Multicast Packet from AR or Other Subnets When the AR receives an IPv6 multicast packet from the edge router, it looks up the multicast routing table and checks whether there Jeong & Jang Expires December 28, 2006 [Page 6] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 exists a receiver of the multicast packet in the AR's subnet. If there is a receiver, the AR sends the packet to the BSs in the downlinks. Each BS in the AR's subnet receives the multicast packet sent from the AR and multicasts the packet to its downlinks by using mCID. In case of a link local multicast packet originated from the AR, the BSs in the AR's subnet transmits the received multicast packet to their downlinks with mCID Jeong & Jang Expires December 28, 2006 [Page 7] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 4. Subnet Model B In this section, we discuss the transport of IPv6 multicast packets over the 'Subnet Model B' depicted in the Figure 3 where a BS is separated from an AR, and a subnet consists of multiple BSs and multiple MSs. This scenario covers the hot-zone deployment model in IEEE 802.11. +-----+ +-----+ +-----+ ISP 1 | MS1 |<-----+ +->| AR1 |----| ER1 |===>Network +-----+ | | +-----+ +-----+ +-----+ | +-----+ | | MS2 |<-----+-----| BS1 |--| +-----+ +-----+ | +-----+ +-----+ ISP 2 +->| AR2 |----| ER2 |===>Network +-----+ +-----+ | +-----+ +-----+ | MS3 |<-----------| BS2 |--+ +-----+ +-----+ <---> IP termination Figure 3: Subnet Model B 4.1. Multicast Packet from MS In the Figure 3, when the BS1 receives a multicast packet originated from the MS1, the BS1 multicasts the packet onto its downlinks by using mCID. After then, the BS1 transmits the packet into the link connected to ARs through IEEE 802.3 Ethernet frame. The BS2 which is on the same link as the BS1, receives the IPv6 multicast packet sent from BS1 and multicasts the packet to its downlinks with predefined mCID. When an AR receives an IPv6 multicast packet transmitted by BSs, it follows the same procedure as Subnet Model A scenario except that both the AR1 and the AR2 simultaneously receive the link local scope multicast packet. In case of non-link local scope multicast packet, the AR1 and the AR2 look up their own multicast routing table and forward the received multicast packet according to the lookup result. 4.2. Multicast Packet from AR or Other Subnets The operation of the BSs and the ARs in this case follows the same procedure as Subnet Model A scenario except that there are two ARs in the network and these ARs have their own multicast routing tables. Jeong & Jang Expires December 28, 2006 [Page 8] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 5. Subnet Model C When a BS and an AR are integrated in a same box, there exist two cases of IPv6 prefix allocation method. The one is to assign an IPv6 prefix to each BS/AR box and the other is to allocate an IPv6 prefix to each MS, similar to 3GPP scenario [RFC 3314]. In this section, we discuss the delivery of IPv6 multicast packets over 'Subnet Model C' shown in Figure 4 where a BS is integrated with an AR, composing one box, and a subnet consisting of only single BS/AR and multiple MSs. +-----+ | MS1 |<------+ +-----+ | +-----+ | +-------+ +--------+ | MS2 |<------+--->|BS/AR1 |---------| Edge | ISP +-----+ +-------+ | Router +==>Network +--------+ +-----+ +-------+ | | MS3 |<---------->|BS/AR2 |-----------+ +-----+ +-------+ <---> IP termination Figure 4: Subnet Model C 5.1. Multicast Packet from MS After the BS/AR1 receiving a multicast packet from the MS1, the BS/ AR1 transmits the received packet to its downlinks by using mCID. If the multicast packet is destined to itself (i.e., link local scope multicast packet), the BS/AR1 processes the multicast packet. In case of a non-link local multicast packet, the BS/AR1 looks up the multicast routing table and forwards the packet to the Edge Router according to the lookup result. The packet forwarded by the BS/AR1 is delivered to the BS/AR2 or the Edge Router by means of conventional IPv6 multicast packet transport procedure. 5.2. Multicast Packet from BS/AR or Other Subnets When the BS/AR1 needs to send a multicast packet to MSs in its subnet, the BS/AR1 transmits the packet to its downlinks with mCID. When the BS/AR1 receives a multicast packet from Edge Router, it looks up the multicast routing table and checks whether the packet is destined to its subnet. If there exists a receiver in the subnet, the BS/AR1 sends the packet to its downlinks by using mCID. Jeong & Jang Expires December 28, 2006 [Page 9] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 6. Subnet Model D In this section, we discuss the delivery of IPv6 multicast packets over 'Subnet Model D' depicted in Figure 5 where a BS is integrated with an AR, composing one box in view of implementation. In this subnet model, each subnet consists of single BS/AR and only one MS. Thus, each MS has a unique IPv6 prefix. This scenario is similar to 3GPP scenario [RFC 3314]. +-----+ | MS1 |<-------------+ +-----+ v +-----+ +-------+ +--------+ | MS2 |<---------->|BS/AR1 |---------| Edge | ISP +-----+ +-------+ | Router +==>Network +--------+ +-----+ +-------+ | | MS3 |<---------->|BS/AR2 |-----------+ +-----+ +-------+ <---> IP termination Figure 5: Subnet Model D 6.1. Multicast Packet from MS If the BS/AR1 receives a link local multicast packet from the MS1, the BS/AR1 has only to process the received multicast packet. In case of a non-link local multicast packet, the BS/AR1 looks up the multicast routing table and forwards the packet to the Edge Router according to the lookup result. Then, the packet will follow a conventional IPv6 multicast packet transport procedure. 6.2. Multicast Packet from BS/AR or Other Subnets When the BS/AR1 needs to send a multicast packet to MSs in its subnet, the BS/AR1 transmits the packet to its downlink by using either mCID or unicast CID. When the BS/AR1 receives a multicast packet from Edge Router, it looks up the multicast routing table and checks whether the packet is destined to its own subnet. If there exists a receiver in the subnet, the BS/AR1 sends the packet to its downlink by using wither mCID or unicast CID. Jeong & Jang Expires December 28, 2006 [Page 10] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 7. Considerations about mCID Format The allocation of mCID to IPv6 multicast packets needs to be considered in IEEE. However, in this memo, we present a candidate. 7.1. IPv6 scope-based mCID Format This section specifies a modification to the CID format as follows. | 11 | 1 | 4 | +------------------------------+---+----------+ | mCID prefix | CS| scop | +------------------------------+---+----------+ Figure 6: IPv6 Scope based mCID Format mCID consists of mCID prefix, CS, and scope field. mCID prefix is used to indicate that a multicast packet is embedded in IEEE 802.16 frame. CS field implies that whether IPv6 CS or Ethernet CS is used to encapsulate the IPv6 packet. CS field with its value 1 implies that IPv6 CS is used and scope field be set to the same value as the scope field of encapsulated IPv6 destination address. CS field with its value 0 indicates that Ethernet CS is used and scope field be set to the same value as the scope field of encapsulated IPv6 destination address. Jeong & Jang Expires December 28, 2006 [Page 11] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 8. IANA Considerations This document requests no action by IANA. Jeong & Jang Expires December 28, 2006 [Page 12] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 9. Security Considerations TBD 10. References [IEEE802.16] "IEEE 802.16-2004, IEEE standard for Local and metropolitan area networks, Part 16:Air Interface for fixed broadband wireless access systems", October 2004. [IEEE802.16e] "IEEE 802.16e/D10 Draft, IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems Amendment for Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands", August 2005. [I-D.jee-16ng-ps-goals] Jee, J., "IP over 802.16 Problem Statements and Goals", draft-jee-16ng-ps-goals-00 (work in progress), February 2006. [I-D.jeon-ipv6-ndp-ieee802.16] Jeon, H. and J. Jee, "IPv6 NDP for Common Prefix Allocation in IEEE 802.16", draft-jeon-ipv6-ndp-ieee802.16-01 (work in progress), March 2006. [I-D.jang-16ng-llm] Jang, H., "Link-local Multicast Packet Transmission in 802.16 Networks", draft-jang-16ng-llm-00 (work in progress), February 2006. [I-D.ietf-v6ops-802-16-deployment-scenarios] Shin, M. and Y. Han, "ISP IPv6 Deployment Scenarios in Wireless Broadband Access Networks", draft-ietf-v6ops-802-16-deployment-scenarios-00 (work in progress), May 2006. [RFC3314] Wasserman, M., "Recommendations for IPv6 in Third Generation Partnership Project (3GPP) Standards", RFC 3314, September 2002. [RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, June 2004. Jeong & Jang Expires December 28, 2006 [Page 13] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 Authors' Addresses Sangjin Jeong ETRI 161 Gajeong-dong, Yusung-gu Daejeon, 305-350 Korea Phone: +82 42 860 1877 Email: sjjeong@gmail.com Heejin Jang SAIT P.O. Box 111 Suwon 440-600 Korea Email: heejin.jang@samsung.com Jeong & Jang Expires December 28, 2006 [Page 14] Internet-Draft IPv6 Multicast over IEEE 802.16 June 2006 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. 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Disclaimer of Validity 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. 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Jeong & Jang Expires December 28, 2006 [Page 15]