16ng Working Group S-E. Kim Internet-Draft J-S. Jin Expires: January 20, 2008 S-C. Lee S-H. Lee KT July 19, 2007 Multicast Transport on IEEE 802.16 Networks draft-sekim-802-16-multicast-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 January 20, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This draft proposes two types of multicast transport over IEEE 802.16 networks. One is deirect mapping for IPv6 CS and the other is indirect mapping for both IPv6 over Ethernet CS and IPv6 over VLAN CS. An IPv6 multicast address transmits directly to a CID of IEEE 802.16 frame in direct mapping scheme. In indirect mapping, an IPv6 multicast address uses [RFC2464] and then transmits to a CID of IEEE Kim, et al. Expires January 20, 2008 [Page 1] Internet-Draft Multicast on IEEE 802.16 July 2007 802.16 frame. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Frame format for IEEE 802.16 Network . . . . . . . . . . . . . 4 4. CS Specific Multicast in IEEE 802.16 Network . . . . . . . . . 5 4.1. Multicast on IPv6 CS . . . . . . . . . . . . . . . . . . . 6 4.2. Multicast on Ethernet CS and IEEE 802.1Q VLAN CS . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 8.1. Normative References . . . . . . . . . . . . . . . . . . . 9 8.2. Informative References . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Intellectual Property and Copyright Statements . . . . . . . . . . 12 Kim, et al. Expires January 20, 2008 [Page 2] Internet-Draft Multicast on IEEE 802.16 July 2007 1. Introduction The [IEEE802.16] standards specify two modes for sharing wireless media. One is point-to-multipoint(PMP) and the other is mesh. This document focuses on PMP mode. In PMP mode, uplink supports only unicast while downlink supports both unicast and multicast. Therefore, [IEEE802.16] is not capable of multicasting in general concept which should support both uplink and downlink as [IEEE802.3] does. [I-D.ietf-16ng-ipv6-over-ipv6cs] describes IPv6 related convergence sublayer for unicast. The multicast transport capabilities are important to both control and bearer aspects in Internet Protocol. For examples, Ethernet Address Resolution Protocol [RFC0826] for IPv4 and Neighbor Discovery for IPv6 [RFC2461] require multicast mechanism for control aspects. The [IEEE802.16] standards specify service specific convergence sublayer to process higher-layer protocol data unit based on classification. The types of service specific convergence sublayer are asynchronous transfer mode (ATM) and packets such as IPv6, IPv4, IEEE 802.3/Ethernet, IEEE 802.1Q VLAN, IPv6 over IEEE 802.3/Ethernet, IPv6 over IEEE 802.1Q VLAN, IPv4 over IEEE 802.3/Ethernet, IPv4 over IEEE 802.1Q VLAN and so on. A multicast capability depends on the convergence sublayer parameters of REGISTRATION message at IEEE 802.16 MAC messages. This document describes IPv6 multicast [RFC4291] transport over IEEE 802.16 networks in accordance with convergence sublayer. 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 [RFC2119]. 2. Terminology o IEEE802.16 : IEEE802.16 standards including IEEE802.16e standards o Base Station (BS):A generalized equipment sets providing connectivity, management, and control between the subscriber stations and the 802.16 networks. o Connection Identifier(CID): A 16 bit value that identifies a connection to equivalent peers in the MAC of the base station and subscriber station. This is specified in IEEE802.16. o Convergence Sublayer (CS): Sublayer in the IEEE 802.16 MAC layer that classifies higher layer data and associates them to the Kim, et al. Expires January 20, 2008 [Page 3] Internet-Draft Multicast on IEEE 802.16 July 2007 proper MAC service flow identifier and connection identifier. o IPv6 CS: A payload for an IEEE 802.16 frame is IPv6 packet. o IPv6 over Ethernet CS: A payload for an IEEE 802.16 frame is Ethernet frame based IPv6 packet. The Eternet frame is a service data unit (SDU) of IEEE802.16 frame. The IPv6 packet is a SDU of an Ethernet frame. o IPv6 over IEEE 802.1Q VLAN CS: A payload for an IEEE 802.16 frame is VLAN frame based IPv6 packet. The VLAN frame is a SDU of IEEE 802.16 frame. The IPv6 packet is a SDU of a VLAN frame. o Mobile Station (MS): An user equipment that supports IP over IEEE 802.16e standard. It SHOULD support mobility capability. 3. Frame format for IEEE 802.16 Network An 802.16 PDU consists of a MAC header, a data payload and CRC as shown in Figure 1. The CRC field is an option. | 48 bits | variable | 32 bits| +-------------------+--------------------+--------+ | 802.16 MAC Header | Payload | CRC | +-------------------+--------------------+--------+ Figure 1: IEEE 802.16 PDU format Figure 2 shows an IEEE802.16 MAC header. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |H|E| TYPE |E|C|EKS|R| LENGTH | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | CID | HCS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: IEEE 802.16 MAC Header o H: Header Type (1 bit). o E: Encryption Control (1 bit). 0 = Payload is not encrypted; 1 = Payload is encrypted. Kim, et al. Expires January 20, 2008 [Page 4] Internet-Draft Multicast on IEEE 802.16 July 2007 o TYPE (6 bits) o E: Extended Subheader Field (1 bit) o C: CRC Indicator. 1 = CRC is included, 0 = 1 No CRC is included o EKS: Encryption Key Sequence (2 bits) o R: Reserved (1 bit). Shall be set to zero. o LENGTH: The Length in bytes of the MAC PDU including the MAC header and the CRC if present (11 bits) o CID: Connection Identifier (16 bits) o HCS: Header Check Sequence (8 bits) Table 1 shows well-known CID in [IEEE802.16e] standard. [IEEE802.16e] describes that "For the downlink multicast service, the same value is assigned to all MSs on the same channel that participate in this connection." +----------------------------+-------------+ | CID | hexadecimal | +----------------------------+-------------+ | Initial Ranging | 0000 | | Basic CID | 0001 ~ m | | Primary management | m+1 ~ 2m | | Transport CIDs | 2m+1 ~ FE9F | | Multicast CID | FEA0 ~ FEFE | | AAS initial ranging CID | FEFF | | Multicast polling CID | FF00~FFF9 | | Normal mode multicast CID | FFFA | | Sleep mode multicast CID | FFFB | | Idle mode multicast CID | FFFC | | Fragmentable Broadcast CID | FFFD | | Padding CID | FFFE | | Broadcast CID | FFFF | +----------------------------+-------------+ Table 1: Usage of CIDs for IEEE 802.16 4. CS Specific Multicast in IEEE 802.16 Network Kim, et al. Expires January 20, 2008 [Page 5] Internet-Draft Multicast on IEEE 802.16 July 2007 4.1. Multicast on IPv6 CS IEEE 802.16 MAC header can be divided into two types: generic MAC header and MAC header without payload. The IEEE 802.16 frame with H=1, MAC header without payload, does not deliver a payload. The Generic MAC header, H=0, begins each MAC PDU containing either MAC management messages or CS data . The IPv6 CS, IPv6 over Ethernet CS and IPv6 over IEEE 802.1Q VLAN CS can be a payload of generic MAC. The 48 bits MAC address is used to identify a network device and used IEEE 802.3 frame format. However, the IEEE 802.16 frame header does not have the MAC address field. Instead, a CID field in the IEEE 802.16 frame header performs link layer identification between MS and BS. An IPv6 CS SHOULD set bit #2 for type 7 in REG-REQ and REG-RSP message as specified by [IEEE802.16]. And this CS uses the value 2 for type 28 in DSx-REQ message. Figure 3 shows IPv6 CS over IEEE 802.16 frame. | 48 bits |IPv6 Packet [RFC2460]| 32 bits| +---------------+-----------+---------+--------+ | 802.16 Header |IPv6 Header| Payload | CRC | +---------------+------+----+---------+--------+ ^ | +--direct mapping-+ Figure 3: IPv6 CS IPv6 multicast address for IPv6 CS over IEEE 802.16 frame SHOULD be used for multicasting with CID field at the 802.16 frame as shown in Figure 4. Kim, et al. Expires January 20, 2008 [Page 6] Internet-Draft Multicast on IEEE 802.16 July 2007 | 8 | 4 | 4 | 108 bits | 4 | +----+----+----+----------------+-+-+-+-+ IPv6 Multicast Address | FF |flgs|scop| multicast group ID | [RFC4291] +----+----+----+----------------+-+-+-+-+ | +----------------------+ | | | 8 | 4 | 4 | +----+----+----+ | FE |scop| ID | Multicast CID for IPv6 CS +----+----+----+ Figure 4: Direct mapping for IPv6 CS The multicast CID, 0XFFA0-0xFEFE, SHOULD use to multicast in IEEE 802.16 specification. The other CIDs are multicast polling CID, normal mode multicast CID, sleep mode multicast CID, idle mode multicast CID, fragmentable broadcast CID and broadcast CID. It is for specific usage and difficult to identify layer 3 multicast addresses. The information for 802.16 multicast in CID SHOULD use scope field and multicast group identifier that specified by [RFC4291]. The scope and multicast group identifier are important to identify multicast address [IPv6MA]. IPv6 multicast address prefix (0xFF) translate to 802.16 CID multicast group (0xFE). The flag information on IPv6 multicast address normally uses zero. So, 802.16 CID SHOULD not use flag in [RFC4291] for multicast mapping. The scope information on IPv6 multicast address is important. Therefore, 802.16 CID SHOULD use scope information for multicasting. The last 4 bits in group identifier are important to IPv6 multicast address [RFC4291]. The multicast group identifier uses last 4 bits to 12 bits based on the purpose. So, last 4 bits of the IPv6 multicast group identifier SHOULD use because only 4 bits are available at CID. The duplication of the last 4 bits for multicast can resolve by use of scope information. The unique identification to the whole IPv6 multicast address requires modification of such specification as [IEEE802.16], [RFC2460], [RFC4291]. Therefore, Figure 3 is RECOMMENDED for IPv6 multicast address mapping to 802.16 CID. Kim, et al. Expires January 20, 2008 [Page 7] Internet-Draft Multicast on IEEE 802.16 July 2007 4.2. Multicast on Ethernet CS and IEEE 802.1Q VLAN CS IPv6 over Ethernet CS SHOULD set bit #6 for type 7 in REG-REQ and REG-RSP message as specified by [IEEE802.16]. And this CS uses the value 6 for type 28 in DSx-REQ message. IPv6 over IEEE 802.1Q VLAN CS SHOULD set bit #8 for type 7 in REG-REQ and REG-RSP message as specified by [IEEE802.16]. And this CS uses the value 8 for type 28 in DSx-REQ message. Figure 5 shows IPv6 over IEEE 802.3/VLAN CS over 802.16 frame. | 48 bits | | IPv6 Packet |32bits| +---------------+------------+-----------+---------+------+ | |802.3 Header| | | | | 802.16 Header | or |IPv6 Header| Payload | CRC | | | VLAN Header| | | | +---------------+----+-------+--------+--+---------+------+ ^ indirect | ^ | +--mapping---+ +--RFC2464--+ Figure 5: IPv6 over Ethernet/VLAN CS IPv6 multicast require at IPv6 over IEEE802.3 or [IEEE802.1Q] VLAN CS. In this case, IPv6 multicast mapping to 802.16 CID SHOULD use either direct mapping or indirect mapping. The direct mapping scheme is described in section 4.1. IPv6 multicast mapping to CID SHOULD use indirect mapping as following. Firstly, [RFC2464] use for IPv6 multicast address mapping to destination address at 802.3 frame. After that, multicast address at 802.3 frame SHOULD translate to 602.16 CID as shown in Figure 6. A BS transmit IPv6 multicast packet that destination address start with 0X3333 at 802.3 frame for IPv6 over IEEE802.3 or VLAN encapsulation Kim, et al. Expires January 20, 2008 [Page 8] Internet-Draft Multicast on IEEE 802.16 July 2007 | 16 | 24 bits | 8 | +------+-----------------+-+-+-+-+-+-+-+-+ Ethernet Multicast Address | 3333 | 802.3 multicast address | [RFC2464] +------+-----------------+-+-+-+-+-+-+-+-+ | +-------------------+ | | | 8 | 8 | +----+--------------+ | FE | multicast ID | Multicast CID for IPv6 over Ethernet CS +----+--------------+ Multicast CID for IPv6 over IEEE 802.1Q VLAN CS Figure 6: Indirect mapping for Ethernet CS and VLAN CS 5. Security Considerations This document does not introduce any new vulnerabilities to IPv6 specifications or operation. The security of the 802.16 air interface is the subject to [IEEE802.16]. 6. IANA Considerations This document requests no action by IANA. 7. Acknowledgements The authors would like to acknowledge the contributions of Dr. Tcha for his review and comments. 8. References 8.1. Normative References [IEEE802.16] "IEEE Standard for Local and metropolitan area networks - Specific requirements - Part 16: Air Interface for Fixed Broadband Wireless Access Systems"", IEEE Standard 802.16, June 2004. [IEEE802.16e] "IEEE Standard for Local and metropolitan area networks - Specific requirements - Part 16: Air Interface for Fixed Kim, et al. Expires January 20, 2008 [Page 9] Internet-Draft Multicast on IEEE 802.16 July 2007 Broadband Wireless Access Systems, Amendment 2: Physical and Medium Access Control layers for Combined Fixed and Mobile Operation in Licensed bands and Corrigendum 1"", IEEE Standard 802.16e, December 2005. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006. 8.2. Informative References [I-D.ietf-16ng-ipv6-over-ipv6cs] Patil, B., "IPv6 Over the IP Specific part of the Packet Convergence sublayer in 802.16 Networks", draft-ietf-16ng-ipv6-over-ipv6cs-09 (work in progress), April 2007. [IEEE802.1Q] Institute of Electrical and Electronics Engineers, "IEEE Standard for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks", IEEE Standard 802.1Q, May 2006. [IEEE802.3] "IEEE Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 3: Carrier sense multiple access with collision detection (CSMA/CD) access method and physical layer specifications"", IEEE Standard 802.3, March 2002. [RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or converting network protocol addresses to 48.bit Ethernet address for transmission on Ethernet hardware", STD 37, RFC 826, November 1982. [RFC2461] Narten, T., Nordmark, E., and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. Kim, et al. Expires January 20, 2008 [Page 10] Internet-Draft Multicast on IEEE 802.16 July 2007 Authors' Addresses Sang-Eon Kim Infra Lab., KT 17 Woomyeon-dong, Seocho-gu Seoul, 137-792 Korea Phone: +82 2 526 6117 Fax: +82 2 526 5200 Email: sekim@kt.co.kr Jong Sam Jin Infra Lab., KT 17 Woomyeon-dong, Seocho-gu Seoul, 137-792 Korea Phone: +82 2 526 6113 Fax: +82 2 526 5200 Email: jongsam@kt.co.kr Seong-Choon Lee Infra Lab., KT 17 Woomyeon-dong, Seocho-gu Seoul, 137-792 Korea Phone: +82 2 526 6153 Fax: +82 2 526 5200 Email: lsc@kt.co.kr Sang-Hong Lee Infra Lab., KT 17 Woomyeon-dong, Seocho-gu Seoul, 137-792 Korea Phone: +82 2 526 6500 Fax: +82 2 526 6502 Email: shleee@kt.co.kr Kim, et al. Expires January 20, 2008 [Page 11] Internet-Draft Multicast on IEEE 802.16 July 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). 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. 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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. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Kim, et al. Expires January 20, 2008 [Page 12]