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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 3344 (Obsoleted by RFC 5944) Summary: 2 errors (**), 0 flaws (~~), 1 warning (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group G. Tsirtsis 3 Internet-Draft V. Park 4 Intended status: Standards Track V. Narayanan 5 Expires: May 12, 2010 Qualcomm 6 K. Leung 7 Cisco 8 November 8, 2009 10 Dynamic Prefix Allocation for NEMOv4 11 draft-ietf-mip4-nemov4-dynamic-03.txt 13 Abstract 15 The base NEMOv4 specification defines extensions to Mobile IPv4 for 16 mobile networks. This specification defines a dynamic prefix 17 allocation mechanism. 19 Status of this Memo 21 This Internet-Draft is submitted to IETF in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF), its areas, and its working groups. Note that 26 other groups may also distribute working documents as Internet- 27 Drafts. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 The list of current Internet-Drafts can be accessed at 35 http://www.ietf.org/ietf/1id-abstracts.txt. 37 The list of Internet-Draft Shadow Directories can be accessed at 38 http://www.ietf.org/shadow.html. 40 This Internet-Draft will expire on May 12, 2010. 42 Copyright Notice 44 Copyright (c) 2009 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the BSD License. 57 Table of Contents 59 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 60 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 61 3. Dynamic Mobile Prefix allocation . . . . . . . . . . . . . . . 5 62 3.1. Mobile Client Considerations . . . . . . . . . . . . . . . 5 63 3.2. Home Agent Considerations . . . . . . . . . . . . . . . . 5 64 4. Security Considerations . . . . . . . . . . . . . . . . . . . 7 65 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 66 6. Normative References . . . . . . . . . . . . . . . . . . . . . 9 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 69 1. Requirements notation 71 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 72 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 73 document are to be interpreted as described in [RFC2119]. 75 2. Introduction 77 The base NEMOv4 specification [RFC5177] defines extensions to Mobile 78 IPv4 [RFC3344] for mobile networks. This specification adds support 79 for dynamic allocation of mobile prefixes by the home agent. 81 3. Dynamic Mobile Prefix allocation 83 The following extension is defined according to this specification. 85 3.1. Mobile Client Considerations 87 [RFC5177] defines that the prefix field of the mobile network request 88 extension can not be set to zero. This mechanism works only in 89 combination with the explicit mode of operation defined in [RFC5177]. 91 According to this specification, a mobile client MAY include one or 92 more mobile network request extensions with the prefix field set to 93 zero. Such mobile network request extensions indicate that the 94 mobile client requests mobile network prefix(es) to be assigned to it 95 by the home agent. In this case, the mobile client MAY set the 96 prefix length field of such extensions to zero or to a length of its 97 choice as a hint to the home agent. According to this specification, 98 mobile network request extensions with the prefix field set to zero 99 MAY be included in a registration request message either during 100 initial registration or during a subsequent registration. 102 When a mobile client receives a registration reply it MUST process it 103 as defined in MIPv4 [RFC3344] and [RFC5177]. If one or more network 104 acknowledgement extension are included with the Code field set to 105 "Success" the mobile client SHOULD treat the prefixes in the 106 corresponding prefix fields as allocated prefixes and create the 107 appropriate bindings as defined in [RFC5177]. 109 If in response to a registration request with a mobile network 110 request extension with the prefix field set to zero, a mobile client 111 receives a registration reply with a network acknowledgement 112 extensiona including Code field set to 1 "invalid prefix", it may use 113 it as a hint that the home agent does not support dynamic prefix 114 allocation. 116 3.2. Home Agent Considerations 118 A home agent receiving a mobile network request extension with the 119 prefix field set to zero MAY return a mobile network acknowledgement 120 extension [RFC5177] with the prefix field set to the prefix allocated 121 to the mobile client. The length of that prefix is at the discretion 122 of the home agent. The home agent MAY take into account the prefix 123 length hint if one is included in the mobile network request 124 extension. Once the home agent allocates a prefix it MUST maintain 125 the prefix registration table as defined in [RFC5177]. Alternatively 126 the home agent MAY return a mobile network acknowledgement extension 127 with the Code field set to one of the negative codes defined in 128 [RFC5177]. 130 Dynamic mobile prefix allocation as defined in this specification MAY 131 be combined with dynamic home address allocation as defined in 132 [RFC5177]. In other words the home address field of the registration 133 request message MAY be set to zero while the message also includes 134 one or more mobile network request extensions with the prefix field 135 also set to zero. 137 Once the home agent allocates a prefix it MUST maintain the prefix 138 registration table as defined in [RFC5177]. The lifetime of the 139 allocated prefix will be equal to the lifetime of the binding cache 140 entry 142 For dynamic prefix allocation the mobile client's home address MAY be 143 used to identify the client if it is not set to zero. Otherwise, as 144 defined in the NAI extension [RFC2794] of MIPv4 [RFC2794], the NAI 145 extension needs to be included in the registration request, in which 146 case the same extension SHOULD be used to identify the mobile client 147 for prefix allocation purposes. 149 4. Security Considerations 151 This specification operates in the security constraints and 152 requirements of MIPv4 [RFC3344], NAI [RFC2794] and [RFC5177]. 154 Home agent implementations SHOULD take steps to prevent address 155 exhaustion attacks. One way to limit the effectiveness of such an 156 attack is to limit the number and size of prefixes any one mobile 157 router can be allocated. 159 5. IANA Considerations 161 This document has no actions for IANA 163 6. Normative References 165 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 166 Requirement Levels", BCP 14, RFC 2119, March 1997. 168 [RFC2794] Calhoun, P. and C. Perkins, "Mobile IP Network Access 169 Identifier Extension for IPv4", RFC 2794, March 2000. 171 [RFC3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344, 172 August 2002. 174 [RFC5177] Leung, K., Dommety, G., Narayanan, V., and A. Petrescu, 175 "Network Mobility (NEMO) Extensions for Mobile IPv4", 176 RFC 5177, April 2008. 178 Authors' Addresses 180 George Tsirtsis 181 Qualcomm 183 Email: tsirtsis@googlemail.com 185 Vincent Park 186 Qualcomm 188 Phone: +908-947-7084 189 Email: vpark@qualcomm.com 191 Vidya Narayana 192 Qualcomm 194 Phone: +858-845-2483 195 Email: vidyan@qualcomm.com 197 Kent Leung 198 Cisco 200 Phone: +408-526-5030 201 Email: kleung@cisco.com