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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references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) == Outdated reference: A later version (-18) exists of draft-ietf-softwire-dslite-multicast-03 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Softwire WG M. Boucadair 3 Internet-Draft France Telecom 4 Intended status: Standards Track J. Qin 5 Expires: April 19, 2013 Cisco 6 T. Tsou 7 Huawei Technologies (USA) 8 X. Deng 9 France Telecom 10 October 16, 2012 12 DHCPv6 Option for IPv4-Embedded Multicast and Unicast IPv6 Prefixes 13 draft-ietf-softwire-multicast-prefix-option-02 15 Abstract 17 This document defines Dynamic Host Configuration Protocol version 6 18 (DHCPv6) Option for multicast transition solutions, aiming to convey 19 the IPv6 prefixes to be used to build unicast and multicast IPv4- 20 embedded IPv6 addresses. 22 Status of this Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on April 19, 2013. 39 Copyright Notice 41 Copyright (c) 2012 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 57 1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 3. PREFIX64 DHCPv6 Option . . . . . . . . . . . . . . . . . . . . 3 60 4. Configuration Guidelines (Server Side) . . . . . . . . . . . . 5 61 5. DHCPv6 Client Behaviour . . . . . . . . . . . . . . . . . . . . 5 62 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 63 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 64 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 65 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 66 9.1. Normative References . . . . . . . . . . . . . . . . . . . 6 67 9.2. Informative References . . . . . . . . . . . . . . . . . . 6 68 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 70 1. Introduction 72 Several solutions (e.g., [I-D.ietf-softwire-dslite-multicast]) are 73 proposed for the delivery of multicast services in the context of 74 transition to IPv6. Even if these solutions may have different 75 applicable use cases, they all use specific IPv6 addresses to embed 76 IPv4 addresses, for both multicast group, and multicast source 77 addresses. 79 This document defines a DHCPv6 option [RFC3315] to convey the IPv6 80 prefixes to be used for constructing these IPv4-embedded IPv6 81 addresses. 83 This option can be in particular used in the context of DS-Lite 84 [RFC6333], Stateless A+P [RFC6346] and other IPv4-IPv6 transition 85 techniques. 87 1.1. Requirements Language 89 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 90 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 91 document are to be interpreted as described in RFC 2119 [RFC2119]. 93 2. Terminology 95 This document makes use of the following terms: 97 o IPv4-embedded IPv6 address: is an IPv6 address which embeds a 32 98 bit-encoded IPv4 address [RFC6052]. An IPv4-embedded IPv6 address 99 can be a unicast or a multicast address. 100 o PREFIX64: is a dedicated IPv6 prefix for building IPv4-embedded 101 IPv6 addresses. A PREFIX64 can be of unicast or multicast. 102 o ASM_PREFIX64: denotes a multicast PREFIX64 which belongs to the 103 Any-Source Multicast (ASM) range. 104 o SSM_PREFIX64: denotes a multicast PREFIX64 which belongs to the 105 Source-Specific Multicast (SSM, [RFC4607]) range. 106 o U_PREFIX64: denotes a unicast PREFIX64 for building the IPv4- 107 embedded IPv6 addresses of multicast sources in SSM mode. 109 3. PREFIX64 DHCPv6 Option 111 OPTION_PREFIX64 (Figure 1) conveys the IPv6 prefix(es) to be used 112 (e.g., by a mB4 [I-D.ietf-softwire-dslite-multicast]) to synthesize 113 IPv4-embbedded IPv6 addresses. 115 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 116 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 117 | OPTION_PREFIX64 | option-length | 118 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 119 | asm-length | | 120 +-+-+-+-+-+-+-+-+ : 121 : ASM_PREFIX64 (12 octets) : 122 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 123 | ssm-length | | 124 +-+-+-+-+-+-+-+-+ : 125 : SSM_PREFIX64 (12 octets) : 126 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 127 | unicast-length| | 128 +-+-+-+-+-+-+-+-+ : 129 : U_PREFIX64 (12 octets) : 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 Figure 1: DHCPv6 Option Format for PREFIX64 134 The fields of the option shown in Figure 1 are as follows: 136 option-code: OPTION_PREFIX64 (see Section 8). 137 option-length: 39 octets. 138 asm-length: the length for the ASM IPv4-emebdded IPv6 prefix in 139 bits. If the field is set to 0, all bits of ASM_PREFIX64 field 140 MUST be set to zeros. 141 ASM_PREFIX64: this field identifies the IPv6 multicast prefix to be 142 used to synthesize the IPv4-embedded IPv6 addresses of the 143 multicast groups. The conveyed multicast IPv6 prefix MUST belong 144 to the ASM range. 145 ssm-length: the length for the SSM IPv4-emebdded IPv6 prefix in 146 bits. If the field is set to 0, all bits of SSM_PREFIX64 field 147 MUST be set to zeros. 148 SSM_PREFIX64: this field identifies the IPv6 multicast prefix to be 149 used to synthesize the IPv4-embedded IPv6 addresses of the 150 multicast groups. The conveyed multicast IPv6 prefix MUST belong 151 to the SSM range. 152 unicast-length: the length for the unicast IPv4-emebdded IPv6 prefix 153 in bits. If the field is set to 0, all bits of U_PREFIX64 field 154 MUST be set to zeros. 155 U_PREFIX64: this field identifies the IPv6 unicast prefix to be used 156 in SSM mode for constructing the IPv4-embedded IPv6 addresses of 157 the multicast sources. It may also be used to extract the IPv4 158 address from the received multicast data flows. The address 159 mapping MUST follow the guidelines documented in [RFC6052]. 161 4. Configuration Guidelines (Server Side) 163 DHCP servers supporting OPTION_PREFIX64 should be configured with 164 U_PREFIX64 and at least one ASM_PREFIX64 or one SSM_PREFIX64. 166 Both ASM_PREFIX64 and SSM_PREFIX64 may be configured and therefore be 167 returned to a requesting DHCP client; it is deployment-specific. In 168 particular, if both SSM and ASM modes are supported, ASM_PREFIX64 and 169 SSM_PREFIX64 prefixes must be configured. For SSM deployments, both 170 SSM_PREFIX64 and U_PREFIX64 should be configured. 172 5. DHCPv6 Client Behaviour 174 To retrieve the IPv6 prefixes that will be used to synthesize unicast 175 and multicast IPv4-embedded IPv6 addresses, the DHCPv6 client MUST 176 include OPTION_PREFIX64 in its OPTION_ORO. If the DHCPv6 client 177 receives more than one OPTION_PREFIX64 option from the DHCPv6 server: 178 o If all the enclosed IPv4-embedded IPv6 multicast prefixes have the 179 same scope, the first instance of the option MUST be used. 180 o If each enclosed IPv4-embedded IPv6 multicast prefix has a 181 distinct scope, the client MUST select the appropriate IPv4- 182 embedded IPv6 multicast prefix having a scope matching the IPv4 183 multicast address used to synthesize an IPv4-embedded IPv6 184 multicast address. 186 If asm-length, ssm-length and unicast-length fields are all set to 0, 187 the DHCPv6 client MUST behave as if OPTION_PREFIX64 had not been 188 received in the response received from the DHCPv6 server. 190 If the asm-length field is non-null, the IPv6 prefix identified by 191 ASM_PREFIX64 is used to synthesize IPv4-embedded IPv6 multicast 192 addresses in the ASM range. This is achieved by concatenating the 193 ASM_PREFIX64 and the IPv4 multicast address; the Pv4 multicast 194 address is inserted in the last 32 bits of the IPv4-embedded IPv6 195 multicast address. 197 If the ssm-length field is non-null, the IPv6 prefix identified by 198 SSM_PREFIX64 is used to synthesize IPv4-embedded IPv6 multicast 199 addresses in the SSM range. This is achieved by concatenating the 200 SSM_PREFIX64 and the IPv4 multicast address; the Pv4 multicast 201 address is inserted in the last 32 bits of the IPv4-embedded IPv6 202 multicast address. 204 If the unicast-length field is non-null, the IPv6 prefix identified 205 by U_PREFIX64 field is used to synthesize IPv4-embedded IPv6 unicast 206 addresses as specified in [RFC6052]. 208 6. Security Considerations 210 The security considerations documented in [RFC3315] and [RFC6052] are 211 to be considered. 213 7. Acknowledgements 215 Particular thanks to C. Jacquenet and S. Venaas for their review. 217 8. IANA Considerations 219 Authors of this document requests IANA to assign a new DHCPv6 option: 221 Option Name Value 222 ----------------- ----- 223 OPTION_PREFIX64 TBA 225 9. References 227 9.1. Normative References 229 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 230 Requirement Levels", BCP 14, RFC 2119, March 1997. 232 [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., 233 and M. Carney, "Dynamic Host Configuration Protocol for 234 IPv6 (DHCPv6)", RFC 3315, July 2003. 236 [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for 237 IP", RFC 4607, August 2006. 239 [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. 240 Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, 241 October 2010. 243 9.2. Informative References 245 [I-D.ietf-softwire-dslite-multicast] 246 Qin, J., Boucadair, M., Jacquenet, C., Lee, Y., and Q. 247 Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients 248 over an IPv6 Multicast Network", 249 draft-ietf-softwire-dslite-multicast-03 (work in 250 progress), August 2012. 252 [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 253 Stack Lite Broadband Deployments Following IPv4 254 Exhaustion", RFC 6333, August 2011. 256 [RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the 257 IPv4 Address Shortage", RFC 6346, August 2011. 259 Authors' Addresses 261 Mohamed Boucadair 262 France Telecom 263 Rennes 35000 264 France 266 Email: mohamed.boucadair@orange.com 268 Jacni Qin 269 Cisco 270 China 272 Phone: 273 Email: jacni@jacni.com 275 Tina Tsou 276 Huawei Technologies (USA) 277 2330 Central Expressway 278 Santa Clara 279 USA 281 Phone: +1 408 330 4424 282 Email: tina.tsou.zouting@huawei.com 284 Xiaohong Deng 285 France Telecom 286 Beijing 287 China 289 Email: xiaohong.deng@orange.com