Network Working Group J. Jee, Editor Internet-Draft M-K. Shin, Editor Expires: April 19, 2006 ETRI E-K. Paik KT J. Cha ETRI G. Montenegro Microsoft Corporation October 16, 2005 16ng Problem Statement draft-jee-16ng-problem-statement-02.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 April 19, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document describes the IPv6 over IEEE 802.16(e) networks (16ng) problem statement. Jee, Editor, et al. Expires April 19, 2006 [Page 1] Internet-Draft 16ng Problem Statement October 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 8 Jee, Editor, et al. Expires April 19, 2006 [Page 2] Internet-Draft 16ng Problem Statement October 2005 1. Introduction Broadband Wireless Access networks address the inadequacies of low bandwidth wireless communication for user requirements such as high quality data/voice service, fast mobility, wide coverage, etc. The IEEE 802.16 Working Group on Broadband Wireless Access Standards develops standards and recommended practices to support the development and deployment of broadband Wireless Metropolitan Area Networks. Additionally, IEEE 802.16e is an amendment that adds support for mobility over the base IEEE 802.16 specification. Recently, the WiMAX Forum, and, in particular, its NWG (Network Working Group) is defining the IEEE 802.16(e) network architecture (e.g., IPv4, IPv6, Mobility, Interworking with different networks, AAA, etc). The NWG is thus taking on work at layers above those defined by the IEEE 802 standards (typically limited to the physical and link layers only). Similarly, WiBro (Wireless Broadband), a Korean effort which focuses on the 2.3 GHz spectrum band, is also based on the IEEE 802.16e specification. IEEE 802.16(e) is different from existing wireless access technologies such as IEEE 802.11 or 3G. Accordingly, while 802.16 defines the encapsulation of an IP datagram in an IEEE 802.16 MAC payload, complete description of IP operation is not present. Thus, IP operation over IEEE 802.16(e) can benefit from IETF input and specification. This document will describe the problems identified in adopting IPv6 over IEEE 802.16(e) networks. 2. Requirements 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] . 3. Terminology The following terms come from IEEE 802.16 [IEEE802.16] and IEEE 802.16e [IEEE802.16e] specifications. Base station (BS): A generalized equipment sets providing connectivity, management, and control of the subscriber station (SS). Subscriber station (SS): A generalized equipment set providing connectivity between subscriber equipment and a base station (BS) MOB_HO-IND: Handover indication message from SS to BS. Jee, Editor, et al. Expires April 19, 2006 [Page 3] Internet-Draft 16ng Problem Statement October 2005 REG-RSP: Registraion response message from BS to SS. 4. Problem Statement The first problem identified in adopting IPv6 over IEEE 802.16(e) networks is that IEEE 802.16(e) is different from existing wireless access technologies such as IEEE 802.11 or 3G. For example: immediately subsequent to network entry, an 802.16 SS (Subscriber Station) has no capability whatsoever for data (as opposed to management) connectivity. The criteria by which the BS (Base Station) sets up the 802.16 MAC connections for data transport is not part of the 802.16 standard and depends on the type of data services being offered (ie. the set up of transport connections will be different for IPv4 and IPv6 services). Additionally - as 802.16 is a point-to-multipoint network - an 802.16 subscriber station is not capable of broadcasting (e.g., for neighbor discovery) or direct communication to the other nodes in the network. While the built-in LAN emulation feature of 802.16 ("802.3 Convergence Sublayer") rectifies this, it may involve additional packet overhead. This lacking of facility for native multicasting for IPv6 packet transfer results in inappropriateness to apply the standard Neighbor Discover Protocol specially regarding, address resolution, router discovery, duplicated address detection and stateless auto-configuration. The second problem identified in adopting IPv6 over IEEE 802.16(e) networks is applying the Fast Handovers for Mobile IPv6 [RFC4068] owing to the difficulty in utilizing the layer 2 handover information. From RFC 4068, mobile node is recommended to send FBU (Fast Binding Update) message to the PAR (Previous Access Router) based on the accurate target BS information on the connected link to operate as predictive mode. In IEEE 802.16e [IEEE 802.16e], the mobile subscriber station decides the ultimate target base station and sends the MOB_HO-IND message to the serving BS to notify the decided target BS information which results in disabling any IPv6 packet transfer on that link. This means that the layer 3's fast handover processing needs to break into the layer 2 processing, between the target decision and the MOB_HO-IND message transfer, to operate as predictive mode. Normally, this kind of intervention is not preferred, because this requires certain interruption of the layer 2 processing, eventually resulting in the handover delay. For reactive mode, utilizing the "Link up" trigger to immediately initiate sending FNA (Fast Neighbor Advertisement) or performing DNA (Detecting Network Attachment) procedures is highly desirable to reduce delay and packet loss. In IEEE 802.16(e) networks, a SS receives a REG-RSP message from the serving BS when the registration is accepted. This registration authorizes a SS to forward IP traffic to the network. Thus, receiving the REG-RSP can be mapped as "Link Jee, Editor, et al. Expires April 19, 2006 [Page 4] Internet-Draft 16ng Problem Statement October 2005 up" trigger in IEEE 802.16(e) networks. Accrodingly, special considerations will be required when implementing Fast Mobile IPv6 (RFC 4068), something which may be pursued in the MIPSHOP WG. The third problem identified in adopting IPv6 over IEEE 802.16(e) networks is applying IP multicasting services. In IEEE 802.16 networks, two types of access to multicast and broadcast services (MBS) may be supported : single-BS access and multi-BS access. Single-BS access is implemented over multicast and broadcast transport connections within one BS, while multi-BS access is implemented by transmitting data from Service Flow(s) over multiple BS. However, the MBS seems to be broadcast services, not multicasting. MBS adheres to broadcast service, while traditional IP multicast schemes define multicast routing using shared trees or a source-specific tree to deliver packets efficiently. Therefore, two types of MBS services need to be mapped into source-specific multicast service, if necessary. 5. Security Considerations None of considerations are required in this section. 6. Acknowledgment We would like to express thanks to IETF Mobility Working Group members of KWISF (Korea Wireless Internet Standardization Forum) for their efforts on this work. We would particularly like to thank to Jeff Mandin for his valuable inputs for problem statement and characterization of the 802.16 MAC. We also would like to express special thanks to Soohong Daniel Park, Heeyoung Jung, Sung Il Kim, Se Jun Park, Sang Eon Kim, Han-Lim Kim and Jung-Mo Moon for their valuable inputs. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Jee, Editor, et al. Expires April 19, 2006 [Page 5] Internet-Draft 16ng Problem Statement October 2005 7.2. Informative References [IEEE802.16] IEEE Std 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 P802.16e/D10, "Draft IEEE Standard for Local and metropolitan area networks, Amendment for Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands", Auguest 2005. [RFC1883] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 1883, December 1995. [RFC2461] Narten, T., Nordmark, E., and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. [RFC2462] Thomson, S. and T. Narten, "IPv6 Stateless Address Autoconfiguration", RFC 2462, December 1998. [RFC4068] Koodli, R., "Fast Handovers for Mobile IPv6", RFC 4068, July 2005. Jee, Editor, et al. Expires April 19, 2006 [Page 6] Internet-Draft 16ng Problem Statement October 2005 Authors' Addresses Junghoon Jee ETRI Email: jhjee@etri.re.kr Myung-Ki Shin ETRI Email: mkshin@etri.re.kr Eun-Kyoung Paik KT Email: euna@kt.co.kr Jaesun Cha ETRI Email: jscha@etri.re.kr Gabriel Montenegro Microsoft Corporation Email: gabriel_montenegro_2000@yahoo.com Jee, Editor, et al. Expires April 19, 2006 [Page 7] Internet-Draft 16ng Problem Statement October 2005 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. 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 (2005). 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. Jee, Editor, et al. Expires April 19, 2006 [Page 8]