Personal G. Tsirtsis V. Park V. Narayanan Internet Draft Qualcomm K. Leung Cisco Document: draft-tsirtsis-nemov4-dynamic-00.txt Expires: December 2006 June 2006 Dynamic Prefix Allocation for NEMOv4 draft-tsirtsis-nemov4-dynamic-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 max 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 2006. Copyright Notice Copyright (C) The Internet Society (2006). `1 <2006> Abstract The base NEMOv4 specification [NEMOv4] defines extensions to Mobile IPv4 [MIPv4] for mobile networks. This specification defines a dynamic prefix allocation mechanism. INDEX 1. Introduction.......................................................3 2. Dynamic Mobile Prefix allocation...................................3 2.1 Mobile Client Considerations......................................3 2.2 Home Agent Considerations.........................................4 3. Security Considerations............................................4 4. References.........................................................5 Author's Addresses....................................................5 Intellectual Property Statement.......................................6 2 <2006> 1. Introduction The base NEMOv4 specification [NEMOv4] defines extensions to Mobile IPv4 [MIPv4] for mobile networks. This specification adds support for dynamic allocation of mobile prefixes by the home agent. 2. Dynamic Mobile Prefix allocation 2.1 Mobile Client Considerations [NEMOv4] defines that the prefix field of the mobile network request extension can not be set to zero. According to this specification, however, a mobile client MAY include one or more mobile network request extensions with the prefix field set to zero. Such mobile network request extensions indicate that the mobile client requests mobile network prefix(es) to be assigned to it by the home agent. In this case, the mobile client MAY set the prefix length field of such extensions to zero or to a length of its choice as a hint to the home agent. According to this specification, mobile network request extensions with the prefix field set to zero MAY be included in a registration request message either during initial registration or during a subsequent registration. When a mobile client receives a registration reply it MUST process it as defined in [MIPv4] and [NEMOv4]. If one or more network acknowledgement extension are included with the Code field set to "Success" the mobile client SHOULD treat the prefixes in the corresponding prefix fields as allocated prefixes and create the appropriate bindings as defined in [NEMOv4]. If in response to a registration request with a mobile network request extension with the prefix field set to zero, a mobile client receives a registration reply with a Code field set to 70 "poorly formed request", it may use it as a hint that the home agent does not support dynamic prefix allocation. [Ed. Note: alternatively [NEMOv4] should define an appropriate Code in the Mobile Network Acknowledgment extension e.g., "Bad Prefix"] 3 <2006> 2.2 Home Agent Considerations A home agent receiving a mobile network request extension with the prefix field set to zero MAY return a mobile network acknowledgement extension [NEMOv4] with the prefix field set to the prefix allocated to the mobile client. The length of that prefix is at the discretion of the home agent. The home agent MAY take into account the prefix length hint if one is included in the mobile network request extension. Once the home agent allocates a prefix it MUST maintain the prefix registration table as defined in [NEMOv4]. Alternatively the home agent MAY return a mobile network acknowledgement extension with the Code field set to one of the negative codes defined in [NEMOv4]. Dynamic mobile prefix allocation as defined in this specification MAY be combined with dynamic home address allocation as defined in [MIPv4]. In other words the home address field of the registration request message MAY be set to zero while the message also includes one or more mobile network request extensions with the prefix field also set to zero. Once the home agent allocates a prefix it MUST maintain the prefix registration table as defined in [NEMOv4]. For dynamic prefix allocation the mobile client's home address MAY be used to identify the client if it is not set to zero. If the home Otherwise, as defined in [MIPv4] and [NAI], the NAI extension [NAI] needs to be included in the registration request, in which case the same extension SHOULD be used to identify the mobile client for prefix allocation purposes. 3. Security Considerations This specification operates in the security constraints and requirements of [MIPv4], [NAI] and [NEMOv4]. Home agent implementations SHOULD take steps to prevent address exhaustion attacks. One way to limit the effectiveness of such an attack is to limit the number and size of prefixes any one mobile router can be allocated. 4 <2006> 4. References [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [MIPv4] C. Perkins, "Mobility Support for IPv4", RFC3344 [NAI] P.Calhoun, C. Perkins, "Mobile IP Network Access Identifier Extension for IPv4", RFC2794 [NEMOv4] K. Leung, et al,, "IPv4 Network Mobility (NEMO) Basic Support Protocol", Feb 06, draft-ietf-nemo-v4-base Author's Addresses George Tsirtsis Qualcomm Inc Phone: +908-947-7059 Email1: tsirtsis@qualcomm.com Email2: tsirtsisg@yahoo.com Vincent Park Qualcomm Inc Phone: +908-947-7084 E-mail: vpark@qualcomm.com Vidya Narayanan Qualcomm Inc Phone: E-mail:vidyan@qualcomm.com Kent Leung Cisco Systems Phone: 408-526-5030 E-mail:kleung@cisco.com 5 <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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