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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group N. Matsuhira 3 Internet-Draft WIDE Project 4 Intended status: Informational 4 April 2022 5 Expires: 6 October 2022 7 Multiple IPv4 - IPv6 address mapping encapsulation - fixed prefix (M46E- 8 FP) 9 draft-matsuhira-m46e-fp-12 11 Abstract 13 This document specifies Multiple IPv4 - IPv6 address mapping 14 encapsulation - fixed prefix (M46E-FP) specification. M46E-FP makes 15 backbone network to IPv6 only. And also, M46E-FP can stack many IPv4 16 networks, i.e. the networks using same IPv4 (private) addresses, 17 without interdependence. 19 Requirements Language 21 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 22 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 23 document are to be interpreted as described in RFC 2119 [RFC2119]. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on 6 October 2022. 42 Copyright Notice 44 Copyright (c) 2022 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 (https://trustee.ietf.org/ 49 license-info) in effect on the date of publication of this document. 50 Please review these documents carefully, as they describe your rights 51 and restrictions with respect to this document. Code Components 52 extracted from this document must include Revised BSD License text as 53 described in Section 4.e of the Trust Legal Provisions and are 54 provided without warranty as described in the Revised BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. Architecture of M46E-FP . . . . . . . . . . . . . . . . . . . 3 60 3. Basic Network Configuration . . . . . . . . . . . . . . . . . 5 61 4. Basic Function of M46E-FP . . . . . . . . . . . . . . . . . . 6 62 4.1. IPv4 over IPv6 Encapsulation / Decapsulation . . . . . . 6 63 4.2. M46A architecture . . . . . . . . . . . . . . . . . . . . 7 64 4.3. Route Advertisement . . . . . . . . . . . . . . . . . . . 8 65 5. Stacking IPv4 Networks . . . . . . . . . . . . . . . . . . . 9 66 6. Redundancy of M46E-FP . . . . . . . . . . . . . . . . . . . . 9 67 7. Example of M46E-FP Operation . . . . . . . . . . . . . . . . 10 68 7.1. Basic M46E-FP Operation . . . . . . . . . . . . . . . . . 10 69 7.2. M46E-FP Operation with plane ID . . . . . . . . . . . . . 12 70 8. Characteristic . . . . . . . . . . . . . . . . . . . . . . . 15 71 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 72 10. Security Considerations . . . . . . . . . . . . . . . . . . . 16 73 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 74 11.1. Normative References . . . . . . . . . . . . . . . . . . 16 75 11.2. References . . . . . . . . . . . . . . . . . . . . . . . 17 76 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17 78 1. Introduction 80 This document provides Multiple IPv4 - IPv6 address maping 81 encapsulation - fixed prefix (M46E-FP) specification. 83 The basic strategy for IPv6 deployment is dual stack. Viewing this 84 strategy from operational side, operation cost of dual stack is 85 higher than single stack operation. Viewing from future, IPv6 only 86 operation is more reasonable rather than IPv4 only operation. 87 Therefore IPv6 only operation is desired. 89 M46E-FP makes backbone network to IPv6 only and privide IPv4 90 connectivities. And also, M46E-FP can stack many IPv4 networks, i.e. 91 the networks using same IPv4 (private) address, without 92 interdependence. 94 2. Architecture of M46E-FP 96 IP address contain two information, one is locator information, and 97 another is identifier information. This is basic architecture of 98 internet protocol, and also the Internet, and no difference between 99 IPv4 and IPv6. 101 Locater is a information related "Where", and indentifier is a 102 information related "Who". That mean, IP address's semantics is 103 "Where's Who" meaning. Host is identified whole IP address 104 information, that is "Where's Who", however route to the host is 105 identified just locator information in IP address, that is "Where". 106 See Figure 1. 108 |<------ IP address ------------------>| 109 |<----- Locator ----->|<--Identifier-->| 110 (Where ) (Who) 111 +---------------------+----------------+ 112 | | | 113 +---------------------+----------------+ 115 Figure 1 117 In IPv4 address space, some host has IPv4 address, which consist n 118 bits length identifier and 32 - n bits locator. In Where's Who 119 representation, 32 - n bits "Where" and n bits "Who". 121 Keeping such "Where's Who" relation, IPv4 address can be represent as 122 IPv6 address by expanding "Where" information from 32 - n bits to 128 123 - n bits. Expanding " Where" information, IPv4 address can be mapped 124 to IPv6 address. Figure 2 shows such expanding. 126 |<------------------------ 128 bits ----------------------------->| 127 |<-------------------- 96 bits ------------------->|<-- 32 bits ->| 128 | : | 129 | : | 130 | +-------:------+ 131 | | IPv4 address | 132 | +-------:------+ 133 | |<-Loc->:<-ID->| 134 | | 32-n : n | 135 | | bits : bits | 136 | | : | 137 +--------------------------------------------------+-------:------+ 138 | M46A prefix (no IPv4 network plane ID) | IPv4 address | 139 +--------------------------------------------------+-------:------+ 140 | : | 141 |<------------- Locator (128 - n bits ) ------------------>:<-ID->| 142 | : n | 143 | : bits | 145 Figure 2 147 IPv4 address space contain private address, that is non globally 148 unique IP address. If some identifier which distinguish private 149 address can introduce in IPv6 address space, we can treate IPv4 150 private address as different address in IPv6 address space. This 151 document define such identifier as "IPv4 network plane ID". "IPv6 152 network plane ID" can provide VPN (Virtual Private Network) like 153 service. 155 That is M46A. In M46E-FP address, "Where" information's bit length 156 is 128 -n bits, and "Who" information's bit length is n bits. 157 Figure 3 shows summary of IPv4 address and M46E-FP address relation. 159 |<------------------------ 128 bits ----------------------------->| 160 |<-------------------- 96 bits ------------------->|<-- 32 bits ->| 161 | : | 162 | : | 163 | +-------:------+ 164 | | IPv4 address | 165 | +-------:------+ 166 | |<-Loc->:<-ID->| 167 | | 32-n : n | 168 | | bits : bits | 169 | | : | 170 +--------------------------------------------------+-------:------+ 171 | M46A prefix (no IPv4 network plane ID) | IPv4 address | 172 +--------------------------------------------------+-------:------+ 173 | : | 174 | : | 175 | 96 - m bits | m bits | 32 bits | 176 +-----------------------+--------------------------+-------:------+ 177 | M46A prefix | IPv4 network plane ID | IPv4 address | 178 +-----------------------+--------------------------+-------:------+ 179 |<------------- Locator (128 - n bits ) ------------------>:<-ID->| 180 | : n | 181 | : bits | 183 Figure 3 185 3. Basic Network Configuration 187 Figure 4 shows network configuration with M46E-FP. The network 188 consists of three parts. Backbone network, stub network, and M46E- 189 FP. 191 Backbone network is operated with IPv6 only. Stub network has three 192 cases. IPv4 only, Dual Stack (both IPv4 and IPv6), and IPv6 only. 194 M46E-FP connects backbone network and stub network in case IPv4 still 195 works in that stub network. If stub network is IPv6 only, M46E-FP is 196 not needed. 198 Campus network, corporate network, ISP and datacenter network are the 199 example for such network. 201 /---------------------------------------------------\ 202 | | 203 | Backbone Network | 204 | (IPv6 only) | 205 | | 206 \---------------------------------------------------/ 207 | | | 208 +-------+ +-------+ | 209 |M46E-FP| |M46E-FP| | 210 +-------+ +-------+ | 211 | | | 212 /--------------\ /--------------\ /--------------\ 213 | | | | | | 214 | Stub Network | | Stub Network | | Stub Network | 215 | (IPv4 only) | | (Dual Stack) | | (IPv6 only) | 216 | | | | | | 217 \--------------/ \--------------/ \--------------/ 219 Figure 4 221 4. Basic Function of M46E-FP 223 M46E-FP has mainly two function. One is IPv4 over IPv6 Encapsulation 224 / Decapsulation, and another is advertise route for stub network. 226 4.1. IPv4 over IPv6 Encapsulation / Decapsulation 228 M46E-FP encapsulates IPv4 packet to IPv6 from stub network to 229 backbone network, and decapsulates IPv6 packet to IPv4 from backbone 230 network to stub network. Figure 5 shows such movement. 232 +--------+------------+ +----------+--------+------------+ 233 |IPv4 Hdr| Data | --> | IPv6 Hdr |IPv4 Hdr| Data | 234 +--------+------------+ +----------+--------+------------+ 236 +--------+------------+ +----------+--------+------------+ 237 |IPv4 Hdr| Data | <-- | IPv6 Hdr |IPv4 Hdr| Data | 238 +--------+------------+ +----------+--------+------------+ 240 /-------------------\ +-------+ /-----------------------------\ 241 | Stub Network |--|M46E-FP|--| Backbone Network | 242 | (IPv4) | +-------+ | (IPv6 only) | 243 \-------------------/ \-----------------------------/ 244 Figure 5 246 M46E-FP MUST support tunnel MTU discovery [RFC1853]. When 247 encapsulated IPv6 Packet size exceed path MTU and inner IPv4 packet 248 have the Don't Fragment bit is set, M46E-FP MUST return ICMP 249 Destination unreachable message with Type3 Code4, fragmentation 250 needed and DS set [RFC0792]. 252 In case IPv6, M46E-FP just relays IPv6 packet. 254 +----------+------------+ +----------+------------+ 255 | IPv6 Hdr | data | --> | IPv6 Hdr | data | 256 +----------+------------+ +----------+------------+ 258 +----------+------------+ +----------+------------+ 259 | IPv6 Hdr | data | <-- | IPv6 Hdr | data | 260 +----------+------------+ +----------+------------+ 262 /---------------------\ +-------+ /--------------------\ 263 | Stub Network |--|M46E-FP|--| Backbone Network | 264 | (IPv6) | +-------+ | (IPv6 only) | 265 \--------------------/ \---------------------/ 267 Figure 6 269 By IPv4 over IPv6 function, M46E-FP make backbone network to IPv6 270 only. 272 4.2. M46A architecture 274 M46A is a IPv6 address used in outer IPv6 header which encapsulate 275 IPv4 packet by M46E-FP. M46A is described in M46A 276 [I-D.draft-matsuhira-m46a]. 278 Figure 7 shows M46A address architecture 280 | 96 - m bits | m bits | 32 bits | 281 +-----------------------+--------------------------+--------------+ 282 | M46A prefix | IPv4 network plane ID | IPv4 address | 283 +-----------------------+--------------------------+--------------+ 285 Figure 7 287 M46A consists of three parts as follows. 289 M46A prefix 290 M46A prefix. This value is fixed value and preconfigured to all 291 M46E-FP in the networks. 293 IPv4 network plane ID 294 IPv4 network plane ID is an identifier of IPv4 network stack over 295 IPv6 backbone network. This value is preconfigured depend on the 296 M46E-FP belong which IPv4 network plane. For more detail see 297 Section 5. 299 IPv4 address 300 IPv4 address in inner IPv4 packet. 302 M46A is resolved copying IPv4 address in inner IPv4 packet, and 303 preconfigured values, M46A prefix and IPv4 network plane ID. 305 4.3. Route Advertisement 307 M46E-FP converts stub network's IPv4 route to M46E-FP IPv6 route and 308 advertises to backbone network. And reverse direction, M46E-FP 309 converts M46E-FP IPv6 route to IPv4 route, that advertises other IPv4 310 stub networks. 312 The IPv4 route for stub network is map to M46E-FP IPv6 route one to 313 one, so number of route of IPv4 is same as number of route of M46E-FP 314 IPv6 route. Total number of route is same as when backbone network 315 operate dual stack, without M46E-FP. 317 In stub network, usual dynamic routing protocol for IPv4 and IPv6 can 318 be used such as RIPv2 [RFC2453], RIPng [RFC2080], OSPFv2 [RFC2328], 319 OSPFv3 [RFC2740] and IS-IS [RFC1195][RFC5308]. Similarly, in 320 backbone network, usual dynamic routing protocol for IPv6 can be used 321 such as RIPng [RFC2080], OSPFv3 [RFC2740] and IS-IS [RFC5308] . 323 If want using default route, default M46E-FP advertise the route 324 [M46E-FP address prefix/( 96 - m )] as default route. If want using 325 different default route by IPv4 network plane ID, default M46E-FP in 326 IPv4 network plane #1 advertise the route [ M46E-FP address prefix + 327 IPv4 network plane ID #1 / 96] as default route. Figure 10 in 328 Section 7 show the example using default route. 330 5. Stacking IPv4 Networks 332 M46E-FP can provide VPN like service to stub networks by using 333 different IPv4 network plane ID value. 335 If backbone network operator provide IPv4 privates network service to 336 Organization A, backbone network operator sets IPv4 network plane ID 337 value =1 to the M46E-FP which connects stub network of organization 338 A. If there are five stub network of organization A, backbone 339 network operator sets same IPv4 network plane ID = 1, to five M46E- 340 FPs which connect stub network of organization A. If there are one 341 hundred stub network of organization B, backbone network operator 342 sets same IPv4 network plane ID = 2, to one hundred M46E-FPs which 343 connect stub network of organization B. If a new stub network in 344 organization B join, backbone network operator configures same IPv4 345 network plane ID = 2, to the new stub network only, which connect 346 stub network of organization B, and no configuration is needed to one 347 hundred M46E-FPs which are already connected. 349 Such configuration, that means same stub network group to same IPv4 350 network plane ID value, is simple and easy to understand, so, it is 351 expected that possibility of misconfiguration is very low. And also, 352 number of configuration is minimum, that mean, number of 353 configuration is same as number of stub networks, and add new stub 354 network, configure to new one only. 356 Describe above, M46E-FP can provide VPN like service, for example, 357 Intranet or extranet. And, after IPv4 global address running out, 358 some service provider may want to reuse IPv4 private address. M46E- 359 FP can provide such IPv4 private address networks over single IPv6 360 backbone network. By M46E-FP, some service providers may reuse IPv4 361 private address. 363 6. Redundancy of M46E-FP 365 M46E-FP brings no limit for redundancy. Figure 8 shows such example 366 in case two connection between backbone network and stub network. 367 Number of link between backbone network and stub network is not 368 limited, and different type of link can be used, for example, for 369 wire and wireless. 371 Configuration of M46E-FPs, which connect same stub network, is same. 372 That mean same M46E-FP prefix and same IPv4 network plane ID value. 374 /---------------------------------------------------\ 375 | | 376 | Backbone Network | 377 | (IPv6 only) | 378 | | 379 \---------------------------------------------------/ 380 | | | | 381 +-------+ +-------+ +-------+ +-------+ 382 |M46E-FP| |M46E-FP| |M46E-FP| |M46E-FP| 383 +-------+ +-------+ +-------+ +-------+ 384 | | | | 385 /---------------------\ /---------------------\ 386 | | | | 387 | Stub Network | | Stub Network | 388 | (IPv4 only) | | (Dual Stack) | 389 | | | | 390 \---------------------/ \---------------------/ 392 Figure 8 394 7. Example of M46E-FP Operation 396 7.1. Basic M46E-FP Operation 398 Figure 9 shows M46E-FP operation which does not use IPv4 network 399 plane ID. In this example, two stub network is connected to backbone 400 network via M46E-FP. One stub network is 10.1.1.0/24 sub network, 401 and the other is 10.1.2.0/24 sub network. 403 When M46E-FP receives IPv4 route advertisement, then M46E-FP convert 404 this IPv4 route to IPv6 route by address resolution to M46E-FP 405 address, and advertise this IPv6 route to backbone network. When 406 M46E-FP receives IPv6 route advertisements, then M46E-FP converts 407 this IPv6 route to IPv4 route if this IPv6 route is match M46E-FP 408 address ( same prefix with M46E-FP), and advertise this IPv4 route to 409 stub network. 411 In this example. IPv4 route, 10.1.1.0/24 is converted to IPv6 route, 412 :10.1.1.0/120,and IPv4 route, 10.1.2.0/24 is converted 413 to IPv6 route, :10.1.2.0/120 at M46E-FP from stub 414 network to backbone network. And, from backbone network to stub 415 network, IPv6 route, :10.1.1.0/120 is converted to 416 IPv4 route, 10.1.1.0/24, and IPv6 route, :10.1.2.0/120 417 is converted to IPv4 route, 10.1.2.0/24. 419 /-------------\ +-----+ /------------\ +-----+ /-------------\ 420 |Stub Network | | | | Backbone | | | |Stub Network | 421 |(10.1.1.0/24)|--|M46E |--| Network |--|M46E |--|(10.1.2.0/24)| 422 | | | -FP | |(IPv6 only) | | -FP | | | 423 \-------------/ +-----+ \------------/ +-----+ \-------------/ 425 [10.1.1.0/24] ---> [:10.1.1.0/120] ---> [10.1.1.0/24] 426 [10.1.2.0/24] <--- [:10.1.2.0/120] <--- [10.1.2.0/24] 428 +---------+----+ +---------+----+----+ +---------+----+ 429 | data |IPv4| --> | data |IPv4|IPv6| --> | data |IPv4| 430 +---------+----+ +---------+----+----+ +---------+----+ 431 src: 10.1.1.1 src: :10.1.1.1 src: 10.1.1.1 432 dst: 10.1.2.1 dst: :10.1.2.1 dst: 10.1.2.1 434 Figure 9 436 Figure 10 shows the example using default route. Default route is 437 useful in case most packets are routed same path. Typically, access 438 network is one of the example. Although using default route, 439 communication between stub networks can be done. Communication 440 between host 10.1.1.1 and host 10.1.2.1 can be done inside in access 441 network, and does not pass over default M46E-FP. 443 /------------\ 444 | | 445 /-------------\ +-----+ | | +-----+ /-------------\ 446 | Backbone | | | | Access | | | |Stub Network | 447 | Network |--|M46E |--| Network |--|M46E |--|(10.1.1.0/24)| 448 | | | -FP | |(IPv6 only) | | -FP | | | 449 \-------------/ +-----+ | | +-----+ \-------------/ 450 (default) | <--[:10.1.1.0/120] 451 [/96] --> | 452 | | 453 | | +-----+ /-------------\ 454 | | | | |Stub Network | 455 | |--|M46E |--|(10.1.2.0/24)| 456 | | | -FP | | | 457 | | +-----+ \-------------/ 458 | <--[:10.1.2.0/120] 459 | | 460 | | 461 | | +-----+ /-------------\ 462 | | | | |Stub Network | 463 | |--|M46E |--|(10.1.3.0/24)| 464 | | | -FP | | | 465 | | +-----+ \-------------/ 466 | <--[:10.1.3.0/120] 467 | | 468 \------------/ 470 Figure 10 472 7.2. M46E-FP Operation with plane ID 474 Figure 11 shows M46E-FP operation which uses IPv4 network plane ID. 475 In this example, there are two planes, and two stub network in each 476 plane is connected to backbone network via M46E-FP. In each plane, 477 one stub network is 10.1.1.0/24 sub network, and the other is 478 10.1.2.0/24 sub network, that means same IPv4 address is used in 479 different plane. 481 When M46E-FP receives IPv4 route advertisements, then M46E-FP 482 converts this IPv4 route to IPv6 route by address resolution to M46E- 483 FP address, and advertise this IPv6 route to backbone network. When 484 M46E-FP receives IPv6 route advertisements, then M46E-FP converts 485 this IPv6 route to IPv4 route if this IPv6 route is match M46E-FP 486 address ( same prefix with M46E-FP), and advertises this IPv4 route 487 to stub network. 489 In this example in plane #1. IPv4 route, 10.1.1.0/24 is converted to 490 IPv6 route, <#1>:10.1.1.0/120,and IPv4 route, 491 10.1.2.0/24 is converted to IPv6 route, <#1>:10.1.2.0/120 at M46E-FP from stub network to backbone 493 network. And, from backbone network to stub network, IPv6 route, 494 <#1>:10.1.1.0/120 is converted to IPv4 route, 495 10.1.1.0/24, and IPv6 route, <#1>:10.1.2.0/120 is 496 converted to IPv4 route, 10.1.2.0/24. 498 And also, In this example in plane #2. IPv4 route, 10.1.1.0/24 is 499 converted to IPv6 route, <#2>:10.1.1.0/120,and IPv4 500 route, 10.1.2.0/24 is converted to IPv6 route, <#2>:10.1.2.0/120 at M46E-FP from stub network to backbone 502 network. And, from backbone network to stub network, IPv6 route, 503 <#2>:10.1.1.0/120 is converted to IPv4 route, 504 10.1.1.0/24, and IPv6 route, <#2>:10.1.2.0/120 is 505 converted to IPv4 route, 10.1.2.0/24. 507 In IPv6 space, address <#1>:10.1.1.1 and address 508 <#2>:10.1.1.1 are different address, route <#1>:10.1.1.0/120 and route <#2>:10.1.1.0/120 510 are different route, although in IPv4 space, address 10.1.1.1 in 511 plane #1 and 10.1.1.1 in plane#2 are same address, route 10.1.1.0/24 512 in plane#1 and route 10.1.1.0/24 in plane#2 are same route. 514 /------------\ 515 ...................|............|............................ 516 : /-------------\ +-----+ | | +-----+ /-------------\ : 517 : | Stub Network| | | | | | | | Stub Network| : 518 : |(10.1.1.0/24)|--|M46E |--| Backbone |--|M46E |--|(10.1.2.0/24)| : 519 : | | | -FP | | Network | | -FP | | | : 520 : \-------------/ +-----+ |(IPv6 only) | +-----+ \-------------/ : 521 :...........................|............|...........................: 522 | | 523 ...................|............|............................ 524 : /-------------\ +-----+ | | +-----+ /-------------\ : 525 : | Stub Network| | | | | | | | Stub Network| : 526 : |(10.1.1.0/24)|--|M46E |--| |--|M46E |--|(10.1.2.0/24)| : 527 : | | | -FP | | | | -FP | | | : 528 : \-------------/ +-----+ | | +-----+ \-------------/ : 529 :...........................|............|...........................: 530 \------------/ 532 <> 534 [10.1.1.0/24] --> [<#1>:10.1.1.0/120] --> [10.1.1.0/24] 535 [10.1.2.0/24] <-- [<#1>:10.1.2.0/120] <-- [10.1.2.0/24] 537 +---------+----+ +---------+----+----+ +---------+----+ 538 | data |IPv4| --> | data |IPv4|IPv6| --> | data |IPv4| 539 +---------+----+ +---------+----+----+ +---------+----+ 540 src: 10.1.1.1 src: <#1>:10.1.1.1 src: 10.1.1.1 541 dst: 10.1.2.1 dst: <#1>:10.1.2.1 dst: 10.1.2.1 543 <> 545 [10.1.1.0/24] --> [<#2>:10.1.1.0/120] --> [10.1.1.0/24] 546 [10.1.2.0/24] <-- [<#2>:10.1.2.0/120] <-- [10.1.2.0/24] 548 +---------+----+ +---------+----+----+ +---------+----+ 549 | data |IPv4| --> | data |IPv4|IPv6| --> | data |IPv4| 550 +---------+----+ +---------+----+----+ +---------+----+ 551 src: 10.1.1.1 src: <#2>:10.1.1.1 src: 10.1.1.1 552 dst: 10.1.2.1 dst: <#2>:10.1.2.1 dst: 10.1.2.1 554 Figure 11 556 Figure 12shows the example using default route with IPv4 network 557 plane. In this case, default M46E-FP may configure different by each 558 IPv4 network plane. 560 /------------\ 561 ...................|............|............................ 562 : /-------------\ +-----+ | | +-----+ /-------------\ : 563 : | Backbone | | | | | | | | Stub Network| : 564 : | Network |--|M46E |--| Access |--|M46E |--|(10.1.1.0/24)| : 565 : | | | -FP | | Network | | -FP | | | : 566 : \-------------/ +-----+ |(IPv6 only) | +-----+ \-------------/ : 567 : (default) | <--[<#1>:10.1.1.0/120] : 568 : [<#1>/96] --> | : 569 : | | : 570 : | | : 571 : | | +-----+ /-------------\ : 572 : | | | | | Stub Network| : 573 : | |--|M46E |--|(10.1.2.0/24)| : 574 : | | | -FP | | | : 575 : | | +-----+ \-------------/ : 576 : | <--[<#1>:10.1.2.0/120] : 577 :...........................|............|...........................: 578 | | 579 ...................|............|............................ 580 : /-------------\ +-----+ | | +-----+ /-------------\ : 581 : | Backbone | | | | | | | | Stub Network| : 582 : | Network |--|M46E |--| |--|M46E |--|(10.1.1.0/24)| : 583 : | | | -FP | | | | -FP | | | : 584 : \-------------/ +-----+ | | +-----+ \-------------/ : 585 : (default) | <--[<#2>:10.1.1.0/120] : 586 : [<#2>/96] --> | : 587 : | | : 588 : | | : 589 : | | +-----+ /-------------\ : 590 : | | | | | Stub Network| : 591 : | |--|M46E |--|(10.1.2.0/24)| : 592 : | | | -FP | | | : 593 : | | +-----+ \-------------/ : 594 : | <--[<#2>:10.1.2.0/120] : 595 :...........................|............|...........................: 596 | | 597 \------------/ 599 Figure 12 601 8. Characteristic 603 M46E-FP has following useful characteristics. 605 * Reduce backbone network operation cost with IPv6 single stack ( at 606 least less than Dual Stack) 608 * Can allocate IPv4 address to stub networks, which used in backbone 609 network before installing M46E-FP 611 * Less configuration 613 * No need for special protocol 615 * No dependent Layer 2 network 617 * Can Stack IPv4 Private networks 619 * Easy stop IPv4 operation in stub network for future ( just remove 620 M46E-FP) 622 * Provide redundancy 624 9. IANA Considerations 626 This document makes no request of IANA. 628 Note to RFC Editor: this section may be removed on publication as an 629 RFC. 631 10. Security Considerations 633 M46E-FP use automatic Encapsulation / Decapsulation technologies. 634 Security consideration related tunneling technologies are discussed 635 in RFC2893[RFC2893], RFC2267[RFC2267], etc. 637 11. References 639 11.1. Normative References 641 [I-D.draft-matsuhira-m46a] 642 Matsuhira, N., "Multiple IPv4 - IPv6 mapped IPv6 address", 643 1 June 2019. 645 [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, 646 RFC 792, DOI 10.17487/RFC0792, September 1981, 647 . 649 [RFC1853] Simpson, W., "IP in IP Tunneling", RFC 1853, 650 DOI 10.17487/RFC1853, October 1995, 651 . 653 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 654 Requirement Levels", BCP 14, RFC 2119, 655 DOI 10.17487/RFC2119, March 1997, 656 . 658 11.2. References 660 [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and 661 dual environments", RFC 1195, DOI 10.17487/RFC1195, 662 December 1990, . 664 [RFC2080] Malkin, G. and R. Minnear, "RIPng for IPv6", RFC 2080, 665 DOI 10.17487/RFC2080, January 1997, 666 . 668 [RFC2267] Ferguson, P. and D. Senie, "Network Ingress Filtering: 669 Defeating Denial of Service Attacks which employ IP Source 670 Address Spoofing", RFC 2267, DOI 10.17487/RFC2267, January 671 1998, . 673 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 674 DOI 10.17487/RFC2328, April 1998, 675 . 677 [RFC2453] Malkin, G., "RIP Version 2", STD 56, RFC 2453, 678 DOI 10.17487/RFC2453, November 1998, 679 . 681 [RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", 682 RFC 2740, DOI 10.17487/RFC2740, December 1999, 683 . 685 [RFC2893] Gilligan, R. and E. Nordmark, "Transition Mechanisms for 686 IPv6 Hosts and Routers", RFC 2893, DOI 10.17487/RFC2893, 687 August 2000, . 689 [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, 690 DOI 10.17487/RFC5308, October 2008, 691 . 693 Author's Address 695 Naoki Matsuhira 696 WIDE Project 697 Japan 698 Email: naoki.matsuhira@gmail.com