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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) == Missing Reference: '6to4' is mentioned on line 86, but not defined == Missing Reference: 'IPv6' is mentioned on line 144, but not defined == Missing Reference: 'DIS-CUSS' is mentioned on line 367, but not defined == Unused Reference: 'DNSSRV' is defined on line 582, but no explicit reference was found in the text == Unused Reference: 'IPV4' is defined on line 594, but no explicit reference was found in the text == Unused Reference: 'IPV6' is defined on line 596, but no explicit reference was found in the text == Unused Reference: 'MECH' is defined on line 609, but no explicit reference was found in the text == Unused Reference: 'SELECT' is defined on line 612, but no explicit reference was found in the text == Unused Reference: 'DISCUSS' is defined on line 636, but no explicit reference was found in the text ** Obsolete normative reference: RFC 2374 (ref. 'AGGR') (Obsoleted by RFC 3587) ** Obsolete normative reference: RFC 2373 (ref. 'ADDR') (Obsoleted by RFC 3513) ** Obsolete normative reference: RFC 2462 (ref. 'AUTO') (Obsoleted by RFC 4862) ** Obsolete normative reference: RFC 2461 (ref. 'DISC') (Obsoleted by RFC 4861) -- Possible downref: Non-RFC (?) normative reference: ref. 'EUI64' -- Possible downref: Non-RFC (?) normative reference: ref. 'IANA' ** Obsolete normative reference: RFC 2460 (ref. 'IPV6') (Obsoleted by RFC 8200) ** Obsolete normative reference: RFC 3068 (ref. '6TO4ANY') (Obsoleted by RFC 7526) == Outdated reference: A later version (-01) exists of draft-ietf-ngtrans-6to4-multicast-00 -- Possible downref: Normative reference to a draft: ref. '6TO4MULTI' ** Obsolete normative reference: RFC 2893 (ref. 'MECH') (Obsoleted by RFC 4213) -- No information found for draft-ietf-ipngwg-default-addr-select - is the name correct? -- Possible downref: Normative reference to a draft: ref. 'SELECT' -- Possible downref: Non-RFC (?) normative reference: ref. 'FBSD' -- Possible downref: Non-RFC (?) normative reference: ref. 'USAGI' -- Possible downref: Non-RFC (?) normative reference: ref. 'INRIA' ** Downref: Normative reference to an Informational RFC: RFC 2772 (ref. '6BONE') ** Obsolete normative reference: RFC 3041 (ref. 'PRIVACY') (Obsoleted by RFC 4941) ** Obsolete normative reference: RFC 1631 (ref. 'NAT') (Obsoleted by RFC 3022) -- Possible downref: Non-RFC (?) normative reference: ref. 'DISCUSS' Summary: 16 errors (**), 0 flaws (~~), 16 warnings (==), 11 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NGTRANS Working Group Fred L. Templin 3 INTERNET-DRAFT SRI International 4 Expires 21 May 2001 21 November 2001 6 Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) 8 draft-ietf-ngtrans-isatap-02.txt 10 Abstract 12 This document specifies an intra-site automatic tunneling protocol 13 (ISATAP) for connecting IPv6 hosts and routers (nodes) within 14 predominantly IPv4-based networks. This method is based on an IPv6 15 aggregatable global unicast address format (described herein) that 16 embeds the IPv4 address of a node within the EUI-64 format interface 17 identifier. This document assumes that, during the IPv4 to IPv6 co- 18 existence and transition phase, many sites will deploy IPv6 19 incrementally within their IPv4 interior routing domains; especially 20 those sites which have large and complex pre-existing IPv4 21 infrastructures. Within such sites, the address format and methods 22 described in this document will enable IPv6 deployment for nodes that 23 do not share a common link with an IPv6 gateway for their site. 25 While other works in progress in the NGTRANS working group propose 26 mechanisms for assigning globally-unique IPv6 address prefixes to 27 sites and methods for inter-domain routing between such sites, the 28 approach outlined in this memo enables large-scale incremental 29 deployment of IPv6 for nodes within a site's pre-existing IPv4 30 infrastructure without incurring aggregation scaling issues at the 31 border gateways nor requiring site-wide deployment of special IPv4 32 services such as multicast. The approach proposed by this document 33 supports IPv6 routing within both the site-local and global IPv6 34 routing domains as well as automatic IPv6 in IPv4 tunneling across 35 portions of a site's IPv4 infrastructure which have no native IPv6 36 support. Additionally, this approach supports automatic tunneling 37 within sites which use non globally-unique IPv4 address assignments, 38 such as when Network Address Translation [NAT] is used. 40 Status of this Memo 42 This document is an Internet-Draft and is in full conformance with 43 all provisions of Section 10 of RFC2026. 45 Internet-Drafts are working documents of the Internet Engineering 46 Task Force (IETF), its areas, and its working groups. Note that 47 other groups may also distribute working documents as Internet- 48 Drafts. 50 Internet-Drafts are draft documents valid for a maximum of six months 51 and may be updated, replaced, or obsoleted by other documents at any 52 time. It is inappropriate to use Internet- Drafts as reference 53 material or to cite them other than as "work in progress." 55 The list of current Internet-Drafts can be accessed at 56 http://www.ietf.org/ietf/1id-abstracts.txt 58 The list of Internet-Draft Shadow Directories can be accessed at 59 http://www.ietf.org/shadow.html. 61 Copyright Notice 63 Copyright (C) The Internet Society (2001). All Rights Reserved. 65 1. Introduction 67 The IETF NGTRANS working group anticipates an heterogeneous IPv4/IPv6 68 infrastructure in the near future and thus is chartered to develop 69 mechanisms to support IPv4/IPv6 coexistence and transition toward 70 global IPv6 deployment. For the most part, existing NGTRANS 71 approaches focus on inter-domain routing between IPv6 islands using 72 the existing global IPv4 backbone as transit. But, these islands may 73 themselves comprise complex heterogeneous IPv4/IPv6 networks (e.g. 74 large academic or commercial campus intranets) that require intra- 75 domain IPv4 to IPv6 transition mechanisms and strategies as well. In 76 order to address this requirement, this document presents a simple 77 and scalable approach that enables incremental deployment of IPv6 78 nodes within predominantly IPv4-based intranets. We refer to this 79 approach as the Intra-Site Automatic Tunnel Addressing Protocol, or 80 ISATAP (pronounced: "ice-a-tap"). 82 ISATAP is based on an aggregatable global unicast address format that 83 carries a standard 64-bit IPv6 address prefix [ADDR][AGGR] with a 84 specially-constructed 64-bit EUI-64 Interface Identifier [EUI64]. 85 This address format is fully compatible with both native IPv6 and 86 NGTRANS routing practices (e.g. [6to4],[6BONE]). But, the interface 87 identifier in an ISATAP address employs a special construction that 88 encapsulates an IPv4 address suitable for automatic IPv6-in-IPv4 tun- 89 neling. Since tunneling occurs only within the site-level prefix of 90 the ISATAP address, the embedded IPv4 address NEED NOT be globally 91 unique; rather, it need only be topologically correct for (and unique 92 within) the context of the site. 94 ISATAP allows dual-stack nodes that do not share a common link with 95 an IPv6 gateway to join the global IPv6 network by automatically tun- 96 neling IPv6 messages through the IPv4 routing infrastructure within 97 their site. Two methods for automatic discovery of an IPv6 gateway 98 for ISATAP address autoconfiguration are provided. This approach 99 allows large-scale intra-site deployment without incurring aggrega- 100 tion scaling issues at border gateways, since only a single global 101 IPv6 address prefix need be used for the entire site. (Multiple pre- 102 fixes are, however, supported and may be used for site renumbering 103 and simliar purposes.) Finally, this approach supports networks which 104 use non-globally unique IPv4 addresses, such as when private address 105 allocations [PRIVATE] and/or Network Address Translation [NAT] are 106 used. 108 2. Changes 110 Major changes from version 01 to version 02: 112 - Cleaned up text and tightened up terminology. Changed "IPv6 destination 113 address" to "IPv6 next-hop address" under "sending rules". Changed 114 definition of ISATAP prefix to include link and site-local. Changed 115 language in sections 4 and 5 117 - Updated status of Linux implementation 119 Major changes from version 00 to version 01: 121 - Revised draft to require *different* /64 prefixs for ISATAP 122 addresses and native IPv6 addresses. Thus, a node's ISATAP 123 interface is assigned a /64 prefix that is distinct from the 124 prefixes assigned to any other interfaces attached to the 125 node - be they physical or logical interfaces. This approach 126 eliminates ISATAP-specific sending rules presented in earlier 127 draft versions. 129 - Changed sense of 'u/l' bit in the ISATAP address interface 130 identifier to indicate "local scope", since ISATAP interface 131 identifiers are unique only within the scope of the ISATAP 132 prefix. (See section 4.) 134 Major changes from personal draft to version 00: 136 - Title change to provide higher-level description of field of 137 use addressed by this draft. Removed other extraneous text. 139 - Major new section on automatic discovery of off-link IPv6 routers 140 when IPv6-IPv4 compatibility addresses are used. 142 3. Terminology 144 The terminology of [IPv6] applies to this document. Additionally, the 145 following terms are used extensively throughout this document: 147 ISATAP prefix: 148 Any link-local, site-local or globally aggregatable IPv6 prefix declared 149 as such. An ISATAP prefix configures ONLY ISATAP addresses within its 150 scope; native IPv6 addresses SHOULD NOT be configured on an ISATAP prefix. 152 ISATAP address: 153 An IPv6 address with an ISATAP prefix and an IPv4 address embedded in 154 the interface identifier in the manner described in section 4 below. 156 Native IPv6 address: 157 An IPv6 address constructed using a non-ISATAP prefix. 159 ISATAP pseudo-interface: 160 ISATAP encapsulation of IPv6 packets inside IPv4 packets occurs 161 at a point that is logically equivalent to an IPv6 interface, 162 with the link layer being the IPv4 unicast network. This point 163 is referred to as a pseudo-interface. An ISATAP pseudo-interface 164 is assigned an ISATAP address through address autoconfiguration. 166 ISATAP router: 167 An IPv6 router supporting an ISATAP pseudo-interface. It is normally 168 an interior router within an heterogeneous IPv6/IPv4 network. 170 ISATAP host: 171 An IPv6 host which has an ISATAP pseudo-interface. 173 4. ISATAP Address Format 175 In the following sections, we will motivate our proposed extensions 176 of the existing IEEE OUI reserved by the Internet Assigned Numbers 177 Authority [IANA] to support IEEE EUI-64 format addresses as well as 178 the ISATAP address format itself. 180 4.1. IEEE EUI-64 Interface Identifiers in IPv6 Addresses 182 IPv6 aggregatable global and local-use unicast addresses [ADDR] 183 include a 64-bit interface identifier in IEEE EUI-64 format [EUI64], 184 which is specified as the concatenation of a 24-bit company_id value 185 (also known as the OUI) assigned by the IEEE Registration Authority 186 (IEEE/RAC) and a 40-bit extension identifier assigned by the address- 187 ing authority for that OUI. (Normally, the addressing authority is 188 the organization to which the IEEE has allocated the OUI). IEEE EUI- 189 64 interface identifiers are formatted as follows: 191 |0 1|1 3|3 4|4 6| 192 |0 5|6 1|2 7|8 3| 193 +----------------+----------------+----------------+----------------+ 194 |ccccccugcccccccc|ccccccccmmmmmmmm|mmmmmmmmmmmmmmmm|mmmmmmmmmmmmmmmm| 195 +----------------+----------------+----------------+----------------+ 197 Where 'c' are the company-specific bits of the OUI, 'u' is the 198 universal/local bit, 'g' is the individual/group bit and 'm' are the 199 extension identifier bits. (NOTE: [ADDR] specifies that the 'u' bit 200 is inverted from its normal sense in the IEEE context; therefore u=1 201 indicates global scope and u=0 indicates local scope). 203 In order to support encapsulation of legacy IEEE EUI-48 (24-bit) 204 extension identifier values, [EUI64] specifies that the first two 205 octets of the EUI-64 40-bit extension identifier (bits 24 through 39 206 of the EUI-64 address itself) SHALL BE 0xFFFE if the extension iden- 207 tifier encapsulates an EUI-48 value. [EUI64] further specifies that 208 the first two octets of the extension identifier SHALL NOT be 0xFFFF, 209 since this value is reserved by the IEEE/RAC. However, all other 40- 210 bit extension identifier values are available for assignment by the 211 OUI addressing authority. 213 4.2. An EUI-64 Interface Identifier Format for IANA 215 The IANA owns IEEE OUI: 00-00-5E, and [IANA] specifies EUI-48 format 216 (24-bit) interface identifier assignments within that OUI. But, 217 [IANA] does not specify how these legacy EUI-48 assignments will be 218 written in EUI-64 format, nor does it specify a format for future 219 40-bit extension identifier assignments. We propose the following 220 format for EUI-64 addresses within IANA's OUI reservation: 222 |0 2|2 3|3 3|4 6| 223 |0 3|4 1|2 9|0 3| 224 +------------------------+--------+--------+------------------------+ 225 | OUI ("00-00-5E"+u+g) | TYPE | TSE | TSD | 226 +------------------------+--------+--------+------------------------+ 228 Where the fields are: 230 OUI IANA's OUI: 00-00-5E with 'u' and 'g' bits (3 octets) 232 TYPE Type field; indicates how (TSE, TSD) are interpreted (1 octet) 234 TSE Type-Specific Extension (1 octet) 236 TSD Type-Specific Data (3 octets) 238 And the following interpretations are defined based on TYPE: 240 TYPE (TSE, TSD) Interpretation 241 ---- ------------------------- 242 0x00-0xFD RESERVED for future IANA use 243 0xFE (TSE, TSD) together contain an embedded IPv4 address 244 0xFF TSD is interpreted based on TSE as follows: 246 TSE TSD Interpretation 247 --- ------------------ 248 0x00-0xFD RESERVED for future IANA use 249 0xFE TSD contains 24-bit EUI-48 intf id 250 0xFF RESERVED by IEEE/RAC 252 Essentially, if TYPE=0xFE, TSE is treated as an extension of TSD. If 253 TYPE=0xFF, TSE is treated as an extension of TYPE. Other values for 254 TYPE (and hence, other interpretations of TSE, TSD) are reserved for 255 future IANA use. This format conforms to all requirements specified 256 in [EUI64] and supports encapsulation of EUI-48 interface identifiers 257 in the manner described by that document. For example, an existing 258 IANA EUI-48 format multicast address such as: 260 01-00-5E-01-02-03 262 would be written in the IANA EUI-64 format as: 264 01-00-5E-FF-FE-01-02-03 266 But, this proposed format also provides a special TYPE (0xFE) for 267 embedding IPv4 addresses within the IANA 40-bit extension identifier. 268 This special TYPE forms the basis for the ISATAP address format as 269 described in the following sections. 271 4.3. ISATAP Address Construction 273 Using the proposed IANA-specific method for interface identifier con- 274 struction discussed in sections 4.1 and 4.2 (with TYPE=0xFE), and 275 with reference to [ADDR], we can construct an ISATAP address as fol- 276 lows: 278 | 3| 13 | 8 | 24 | 16 | 8 | 8 | 8 | 8 | 32 bits | 279 +--+-----+---+--------+--------+---+---+---+---+---+---+---+----+ 280 |FP| TLA |RES| NLA | SLA | 0x| 0x| 0x| 0x| IPv4 Address | 281 | | ID | | ID | ID | 00| 00| 5E| FE| of Endpoint | 282 +--+-----+---+--------+--------+--------------------------------+ 284 (NOTE: since ISATAP address interface identifiers are interpreted 285 only within the local scope of the /64 ISATAP prefix, we set the u/l 286 bit in the least significant octet of the OUI to '0' to indicate 287 local scope.) 289 By way of example, an existing node with IPv4 address 140.173.129.8 290 might be assigned an IPv6 64-bit prefix of 3FFE:1a05:510:200::/64. We 291 can then construct an ISATAP address for this node as: 293 3FFE:1a05:510:200:0:5EFE:8CAD:8108 295 or (perhaps more appropriately) written as the alternative form for 296 an IPv6 address with embedded IPv4 address found in [ADDR]: 298 3FFE:1a05:510:200:0:5EFE:140.173.129.8 300 Similarly, we can construct the link-local and site-local variants 301 (respectively) of the ISATAP address as: 303 FE80::0:5EFE:140.173.129.8 304 FEC0::200:0:5EFE:140.173.129.8 306 4.4. Advantages 308 By embedding an IPv4 address in the interface identifier portion of 309 an IPv6 address as described in section 4.3, we can construct aggre- 310 gatable global unicast IPv6 addresses that can either be routed glo- 311 bally via the IPv6 infrastructure or automatically tunneled locally 312 across portions of a site's IPv4 infrastructure which have no native 313 IPv6 support. Additionally, a node with both an ISATAP link and a 314 native IPv6 link could act as a router for nodes that share its 315 native link, since the ISATAP node could automatically tunnel mes- 316 sages across a site's IPv4 domain on behalf of the native IPv6 nodes. 317 An example would be deployment of IPv6 on a workgroup LAN. In this 318 case, one host could configure an ISATAP address and act as a router 319 for other hosts which use native IPv6 addresses on the LAN. 321 An additional advantage for our proposed method of embedding an IPv4 322 address in the interface identifier portion of an IPv6 address not 323 found in other approaches such as [6TO4] is that large numbers of 324 ISATAP addresses could be assigned within a common IPv6 routing pre- 325 fix, thus providing maximal aggregation at the border gateways. For 326 example, the single 64-bit IPv6 prefix: 328 3FFE:1a05:510:2412::/64 330 could include literally millions of nodes with ISATAP addresses. 331 This feature would allow a "sparse mode" IPv6 deployment such as the 332 deployment of sparse populations of IPv6 hosts on large numbers of 333 independent links throughout a large corporate Intranet. 335 A final important advantage is that this method supports both sites 336 that use globally unique IPv4 address assignments and those that use 337 non-globally unique IPv4 addresses, such as when private address 338 assignments and/or Network Address Translation are used. By way of 339 analogy to the US Postal system, inter-domain transition approaches 340 such as [6TO4] provide means for routing messages "cross-country" to 341 the "street address" of a distant site while the approach outlined in 342 this document provides localized routing information to reach a 343 specific (mailstop, apartment number, post office box, etc) WITHIN 344 that site. Thus, the site-level routing information need not have 345 relevance outside the scope of that site. 347 5. ISATAP Deployment Considerations 349 Hosts should only use ISATAP on interfaces which do not share a com- 350 mon link with a native IPv6 router. Routers may configure both ISATAP 351 and Native IPv6 links on the same physical interface, but the pre- 352 fixes used will be distinct. An ISATAP router can be configured on 353 any ISATAP link to advertise the prefix(es) administratively assigned 354 to that link. Since ISATAP is NBMA, these advertisements are not 355 periodically multicast by the router, but are solicited by Rtsols 356 sent by hosts. Hosts will configure an ISATAP pseudo-interface and 357 assign it address(es) based on the ISATAP prefix(es) in the solicited 358 Rtadv messages. 360 Following ISATAP address configuration, ISATAP hosts communicate as 361 regular IPv6 peers. The source address of such packets will be in 362 ISATAP format. Replies sent to this address can thus be automatically 363 tunneled over the last IPv6 hop, which occurs on the ISATAP network. 364 While nodes may optionally use stateful configuration to set an ISA- 365 TAP prefix and a "default" route that points to an ISATAP router, a 366 greatly preferred alternative is to provide for automatic intra-site 367 IPv6 router discovery and stateless address autoconfiguration [DIS- 368 CUSS]. The following section presents a means for the automatic 369 discovery of ISATAP routers. 371 5.1. Automatic Discovery of ISATAP Routers 373 As described in [AUTO], a node that does not share a common link with 374 an IPv6 router will NOT receive unsolicited Router Advertisements 375 (Rtadv's), nor will Router Solicitations (Rtsol's) from that node 376 reach an IPv6 router on the local link. But, the node may still be 377 able to connect to the global IPv6 Internet if an ISATAP router for 378 the site exists. Hence, a means for ISATAP router discovery is 379 required. We present the following procedure for a node to initiate 380 ISATAP router discovery (and for an ISATAP router to respond) when an 381 on-link IPv6 router is not available: 383 - The node constructs an ISATAP link local address for itself 384 (as described in section 4.) as: 386 FE80::0:5EFE:V4ADDR_NODE 388 - The node discovers the IPv4 address for an ISATAP router 389 as: V4ADDR_RTR (**) 391 - The node sends an Rtsol to the IPv6 "all-routers-multicast" address 392 tunneled through the IPv4 infrastructure to the ISATAP router's 393 IPv4 address. The addresses used in the IPv6 and IPv4 headers are: 395 ipv6_src: FE80::0:5EFE:V4ADDR_NODE 396 ipv6_dst: FF02::2 397 ipv4_src: V4ADDR_NODE 398 ipv4_dst: V4ADDR_RTR 400 - Upon receiving the tunneled Rtsol, the ISATAP router sends 401 a unicast Rtadv to the unicast address of the node which sent the 402 Rtsol; again, by tunneling the Rtadv through IPv4. The addresses 403 used in the IPv6 and IPv4 headers are: 405 ipv6_src: FE80::0:5EFE:V4ADDR_RTR 406 ipv6_dst: FE80::0:5EFE:V4ADDR_NODE 407 ipv4_src: V4ADDR_RTR 408 ipv4_dst: V4ADDR_NODE 410 - Upon receiving the Rtsol, the originating node performs address 411 autoconfiguration as described in [AUTO] and constructs: 413 - a fully-qualified ISATAP address for use as the source address 414 for an ISATAP pseudo-interface 416 - a default route that points to the ISATAP router 418 Note (**) that the above procedure assumes a means for discovering 419 V4ADDR_RTR. We present two alternative methods for the automatic 420 discovery of V4ADDR_RTR: 422 5.2. DNS Well-Known Service Name 424 The first method for discovering V4ADDR_RTR employs a new DNS Well- 425 Known Service (WKS) name [DNS1,DNS2]. With the establishment of a new 426 well-known service name (e.g. "ISATAPGW"), administrators could pub- 427 lish the IPv4 address of a gateway which implementations could use to 428 discover V4ADDR_RTR. This method has the advantage that it can be 429 deployed immediately using existing mechanisms. However, it requires 430 name service lookups and may not always provide the optimum 431 V4ADDR_RTR resolution for isolated hosts if multiple ISATAP routers 432 are available. 434 5.3. IPv4 Anycast for ISATAP routers 436 [6TO4ANY] proposes an IPv4 anycast prefix for 6to4 relay routers. 437 The proposal suggests an IPv4 prefix assignment '192.88.99.0/24' 438 where the single address '192.88.99.1' is assigned as the "6to4 IPv6 439 relay anycast address". We propose analogous assignments for the pur- 440 pose of an "ISATAP router anycast address". (Whether the reservation 441 of a second /32 assignment from the 6to4 IPv4 anycast prefix proposed 442 in [6TO4ANY] would be possible, or a separate prefix assignment would 443 be required is a matter of debate and TBD.) 445 ISATAP routers would advertise the ISATAP router anycast prefix via 446 the intra-domain IPv4 routing infrastructure. Isolated IPv6 nodes 447 would then use the ISATAP router anycast address as the V4ADDR_RTR 448 IPv4 destination for off-link Rtsol's. This approach has the signifi- 449 cant advantages that: 451 - implementations could hard-code the well-known ISATAP 452 anycast address, thus avoiding service discovery via DNS 454 - an optimum path to an ISATAP router would be ensured 455 by intra-domain IPv4 routing 457 As described above, the IPv4 anycast method for locating ISATAP 458 routers provides significant functional advantages over the DNS 459 approach, while the DNS approach can be implemented immediately pend- 460 ing the registration of a WKS name with IANA. While either method 461 will work, the decision of which to push for standardization is TBD 462 pending discussion at upcoming NGTRANS WG meetings. 464 6. Sending Rules and Routing Considerations 466 Since each node will be assigned one or more ISATAP prefixes which 467 are administratively reserved for use ONLY by ISATAP nodes, no spe- 468 cial sending rules are needed. In particular, correspondent nodes 469 that share a common ISATAP prefix will always exchange messages using 470 their ISATAP pseudo-interfaces, whereas nodes that do not share a 471 common ISATAP prefix will always exchange messages via standard IPv6 472 routing. When sending a message on an ISATAP pseudo-interface, an 473 implementation SHOULD verify that the IPv6 next-hop address employs 474 the ISATAP address construction rules described in section 4 in order 475 to detect mis-configured addresses. No other sending rules are neces- 476 sary. 478 7. Address Selection 480 No special address selection rules are necessary. 482 8. Automatic Deprecation 484 ISATAP addresses are intended for use only by nodes which do not 485 receive native IPv6 Rtadv's due to not sharing a common link with an 486 IPv6 router. When native IPv6 Rtadv's become available (such as when 487 an IPv6 router is deployed on a node's link), the node should con- 488 struct a non-ISATAP aggregatable global IPv6 unicast address using 489 address auto-configuration [AUTO] for a non-ISATAP IPv6 prefix 490 discovered through normal means [DISC]. After the node's native IPv6 491 address is populated in the DNS, the node should eventually cease 492 sending Rtsol's to the ISATAP router and discontinue use of its ISA- 493 TAP pseudo-interface. In this way, ISATAP addresses will gradually 494 (and automatically) disappear as IPv6 routers are widely deployed 495 within sites. 497 9. Multicast Considerations 499 Other works in progress [6TO4MULTI] are currently investigating mul- 500 ticast addressing issues for [6TO4]. The address format discussed in 501 this document is expected to be compatible with those emerging 502 approaches. 504 10. IANA considerations 506 In order to support the EUI-64 address form described in this docu- 507 ment, we propose that IANA adopt the EUI-64 Interface Identifier for- 508 mat specified in section 4.2 for the existing 00-00-5E OUI owned by 509 IANA. No other actions are required by the IANA. 511 11. Security considerations 513 The ISATAP address format does not support privacy extensions for 514 stateless address autoconfiguration [PRIVACY]. However, such privacy 515 extensions are intended primarily to avoid revealing one's MAC 516 address, and the ISATAP address format described in this document 517 accomplishes this same goal. 519 Additional security issues are called out in [6TO4] and probably 520 apply here as well. 522 12. Implementation status 524 The author has implemented the mechanisms described in this draft 525 through modifications to the FreeBSD 3.2-RELEASE [FBSD] operating 526 system with the INRIA [INRIA] IPv6 distribution. As of November 12, 527 2001, a Linux implementation is now integrated in the USAGI Linux 528 distribution [USAGI]. 530 Additionally, Windows XP RC1 will implement elements of the mechanism 531 proposed in this paper. 533 Acknowledgements 535 The original ideas presented in this draft were derived from SRI con- 536 tractual work. The author recognizes that ideas similar to those in 537 this document may have already been presented by others and wishes to 538 acknowledge any other such authors. The author also wishes to ack- 539 nowledge the government contract administrators who sponsored the 540 projects from which these works derived as well as his SRI colleagues 541 with whom he has discussed and reviewed this work, including Monica 542 Farah-Stapleton, Dr. Mike Frankel, J. Peter Marcotullio, Lou Rodri- 543 guez, and Dr. Ambatipudi Sastry. 545 The author acknowledges valuable input from numerous members of the 546 NGTRANS community which has helped guide the direction of the draft. 547 The list of contributors is too long to enumerate, but the input from 548 the community has been vital to the draft's evolution. Alain Durand 549 deserves special mention for contributing the title of this draft and 550 the ISATAP acronym. Additionally, Tim Gleenson and Nathan Lutchansky 551 numerous helpful suggestions for improvement. 553 The author finally wishes to provide special acknowledgement to Dave 554 Thaler, Art Shelest, Richard Draves, and others at Microsoft Research 555 for their ideas on automatic discovery of off-link IPv6 routers. Much 556 of the text in section on deployment considerations derives directly 557 from discussions with Dave, Art, Rich and others. 559 References 561 [AGGR] Hinden., R, O'Dell, M., and Deering, S., "An IPv6 562 Aggregatable Global Unicast Address Format", 563 RFC 2374, July 1998. 565 [ADDR] Hinden, R., and S. Deering, "IP Version 6 Addressing 566 Architecture", RFC 2373, July 1998. 568 [AUTO] Thomson, S., and T. Narten, "IPv6 Stateless Address 569 Autoconfiguration", RFC 2462, December 1998. 571 [DISC] Narten, T., Nordmark, E., and W. Simpson, "Neighbor 572 Discovery for IP Version 6 (IPv6)", RFC 2461, 573 December 1998. 575 [DNS1] Mockapetris, P. "Domain names - concepts and facilities", 576 STD 13, RFC 1034, November 1987. 578 [DNS2] Mockapetris, P. "Domain names - Implementation and Specif- 579 ication", 580 STD 13, RFC 1035, November 1987. 582 [DNSSRV] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for 583 specifying the location of services (DNS SRV)", RFC 2782, 584 February 2000. 586 [EUI64] IEEE, "Guidelines for 64-bit Global Identifier (EUI-64) 587 Registration Authority", 588 http://standards.ieee.org/regauth/oui/tutorials/EUI64.html, 589 March 1997 591 [IANA] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, 592 USC/Information Sciences Institute, October 1994. 594 [IPV4] Postel, J., "Internet Protocol", RFC 791 596 [IPV6] Deering, S., and R. Hinden, "Internet Protocol, Version 6 597 (IPv6) Specification", RFC 2460 599 [6TO4] Carpenter, B., and K. Moore, "Connection of IPv6 Domains 600 via IPv4 Clouds", RFC 3056, February 2001. 602 [6TO4ANY] Huitema, C., "An anycast prefix for 6to4 relay routers", 603 RFC 3068, June 2001. 605 [6TO4MULTI] Thaler, D., "Support for Multicast over 6to4 Networks", 606 draft-ietf-ngtrans-6to4-multicast-00.txt (work in pro- 607 gress) 609 [MECH] Gilligan, R., and E. Nordmark, "Transition Mechanisms for 610 IPv6 Hosts and Routers", RFC 2893, August 2000. 612 [SELECT] Draves, R., Default Address Selection for IPv6, draft- 613 ietf- 614 ipngwg-default-addr-select-06.txt (work in progress) 616 [FBSD] http://www.freebsd.org 618 [USAGI] http://www.linux-ipv6.org 620 [INRIA] ftp://ftp.inria.fr/network/ipv6/ 622 [6BONE] Rockell, R., and R. Fink, RFC 2772, February 2000. 624 [PRIVATE] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G. 625 J., 626 and E. Lear, "Address Allocation for Private Internets", 627 RFC 1918, February 1996. 629 [PRIVACY] Narten, T., R. Draves, "Privacy Extensions for Stateless 630 Address 631 Autoconfiguration in IPv6", RFC 3041, January 2001. 633 [NAT] Egevang, K., and P. Francis, "The IP Network Address 634 Translator (NAT)", RFC 1631, May 1994. 636 [DISCUSS] private discussions with Dave Thaler, Art Shelest, et al. 638 Authors Addresses 640 Fred L. Templin 641 SRI International 642 333 Ravenswood Ave. 643 Menlo Park, CA 94025, USA 645 Email: templin@erg.sri.com 647 Intellectual Property 649 The IETF has been notified of intellectual property rights claimed in 650 regard to some or all of the specification contained in this docu- 651 ment. For more information consult the online list of claimed 652 rights.