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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 Fujitsu Limited 4 Intended status: Informational December 15, 2020 5 Expires: June 18, 2021 7 Multiple IPv4 - IPv6 address mapping encapsulation - fixed prefix (M46E- 8 FP) 9 draft-matsuhira-m46e-fp-09 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 June 18, 2021. 42 Copyright Notice 44 Copyright (c) 2020 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 (https://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 Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. Architecture of M46E-FP . . . . . . . . . . . . . . . . . . . 3 61 3. Basic Network Configuration . . . . . . . . . . . . . . . . . 5 62 4. Basic Function of M46E-FP . . . . . . . . . . . . . . . . . . 6 63 4.1. IPv4 over IPv6 Encapsulation / Decapsulation . . . . . . 6 64 4.2. M46A architecture . . . . . . . . . . . . . . . . . . . . 7 65 4.3. Route Advertisement . . . . . . . . . . . . . . . . . . . 8 66 5. Stacking IPv4 Networks . . . . . . . . . . . . . . . . . . . 8 67 6. Redundancy of M46E-FP . . . . . . . . . . . . . . . . . . . . 9 68 7. Example of M46E-FP Operation . . . . . . . . . . . . . . . . 10 69 7.1. Basic M46E-FP Operation . . . . . . . . . . . . . . . . . 10 70 7.2. M46E-FP Operation with plane ID . . . . . . . . . . . . . 12 71 8. Characteristic . . . . . . . . . . . . . . . . . . . . . . . 15 72 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 73 10. Security Considerations . . . . . . . . . . . . . . . . . . . 16 74 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 75 11.1. Normative References . . . . . . . . . . . . . . . . . . 16 76 11.2. References . . . . . . . . . . . . . . . . . . . . . . . 17 77 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17 79 1. Introduction 81 This document provides Multiple IPv4 - IPv6 address maping 82 encapsulation - fixed prefix (M46E-FP) specification. 84 The basic strategy for IPv6 deployment is dual stack. Viewing this 85 strategy from operational side, operation cost of dual stack is 86 higher than single stack operation. Viewing from future, IPv6 only 87 operation is more reasonable rather than IPv4 only operation. 88 Therefore IPv6 only operation is desired. 90 M46E-FP makes backbone network to IPv6 only and privide IPv4 91 connectivities. And also, M46E-FP can stack many IPv4 networks, i.e. 92 the networks using same IPv4 (private) address, without 93 interdependence. 95 2. Architecture of M46E-FP 97 IP address contain two information, one is locator information, and 98 another is identifier information. This is basic architecture of 99 internet protocol, and also the Internet, and no difference between 100 IPv4 and IPv6. 102 Locater is a information related "Where", and indentifier is a 103 information related "Who". That mean, IP address's semantics is 104 "Where's Who" meaning. Host is identified whole IP address 105 information, that is "Where's Who", however route to the host is 106 identified just locator information in IP address, that is "Where". 107 See Figure 1. 109 |<------ IP address ------------------>| 110 |<----- Locator ----->|<--Identifier-->| 111 (Where ) (Who) 112 +---------------------+----------------+ 113 | | | 114 +---------------------+----------------+ 116 Figure 1 118 In IPv4 address space, some host has IPv4 address, which consist n 119 bits length identifier and 32 - n bits locator. In Where's Who 120 representation, 32 - n bits "Where" and n bits "Who". 122 Keeping such "Where's Who" relation, IPv4 address can be represent as 123 IPv6 address by expanding "Where" information from 32 - n bits to 128 124 - n bits. Expanding " Where" information, IPv4 address can be mapped 125 to IPv6 address. (Figure 2) shows such expanding. 127 |<------------------------ 128 bits ----------------------------->| 128 |<-------------------- 96 bits ------------------->|<-- 32 bits ->| 129 | : | 130 | : | 131 | +-------:------+ 132 | | IPv4 address | 133 | +-------:------+ 134 | |<-Loc->:<-ID->| 135 | | 32-n : n | 136 | | bits : bits | 137 | | : | 138 +--------------------------------------------------+-------:------+ 139 | M46A prefix (no IPv4 network plane ID) | IPv4 address | 140 +--------------------------------------------------+-------:------+ 141 | : | 142 |<------------- Locator (128 - n bits ) ------------------>:<-ID->| 143 | : n | 144 | : bits | 146 Figure 2 148 IPv4 address space contain private address, that is non globally 149 unique IP address. If some identifier which distinguish private 150 address can introduce in IPv6 address space, we can treate IPv4 151 private address as different address in IPv6 address space. This 152 document define such identifier as "IPv4 network plane ID". "IPv6 153 network plane ID" can provide VPN (Virtual Private Network) like 154 service. 156 That is M46A. In M46E-FP address, "Where" information's bit length 157 is 128 -n bits, and "Who" information's bit length is n bits. 158 (Figure 3) shows summary of IPv4 address and M46E-FP address 159 relation. 161 |<------------------------ 128 bits ----------------------------->| 162 |<-------------------- 96 bits ------------------->|<-- 32 bits ->| 163 | : | 164 | : | 165 | +-------:------+ 166 | | IPv4 address | 167 | +-------:------+ 168 | |<-Loc->:<-ID->| 169 | | 32-n : n | 170 | | bits : bits | 171 | | : | 172 +--------------------------------------------------+-------:------+ 173 | M46A prefix (no IPv4 network plane ID) | IPv4 address | 174 +--------------------------------------------------+-------:------+ 175 | : | 176 | : | 177 | 96 - m bits | m bits | 32 bits | 178 +-----------------------+--------------------------+-------:------+ 179 | M46A prefix | IPv4 network plane ID | IPv4 address | 180 +-----------------------+--------------------------+-------:------+ 181 |<------------- Locator (128 - n bits ) ------------------>:<-ID->| 182 | : n | 183 | : bits | 185 Figure 3 187 3. Basic Network Configuration 189 Figure 4 shows network configuration with M46E-FP. The network 190 consists of three parts. Backbone network, stub network, and M46E- 191 FP. 193 Backbone network is operated with IPv6 only. Stub network has three 194 cases. IPv4 only, Dual Stack (both IPv4 and IPv6), and IPv6 only. 196 M46E-FP connects backbone network and stub network in case IPv4 still 197 works in that stub network. If stub network is IPv6 only, M46E-FP is 198 not needed. 200 Campus network, corporate network, ISP and datacenter network are the 201 example for such network. 203 /---------------------------------------------------\ 204 | | 205 | Backbone Network | 206 | (IPv6 only) | 207 | | 208 \---------------------------------------------------/ 209 | | | 210 +-------+ +-------+ | 211 |M46E-FP| |M46E-FP| | 212 +-------+ +-------+ | 213 | | | 214 /--------------\ /--------------\ /--------------\ 215 | | | | | | 216 | Stub Network | | Stub Network | | Stub Network | 217 | (IPv4 only) | | (Dual Stack) | | (IPv6 only) | 218 | | | | | | 219 \--------------/ \--------------/ \--------------/ 221 Figure 4 223 4. Basic Function of M46E-FP 225 M46E-FP has mainly two function. One is IPv4 over IPv6 Encapsulation 226 / Decapsulation, and another is advertise route for stub network. 228 4.1. IPv4 over IPv6 Encapsulation / Decapsulation 230 M46E-FP encapsulates IPv4 packet to IPv6 from stub network to 231 backbone network, and decapsulates IPv6 packet to IPv4 from backbone 232 network to stub network. Figure 5 shows such movement. 234 +--------+------------+ +----------+--------+------------+ 235 |IPv4 Hdr| Data | --> | IPv6 Hdr |IPv4 Hdr| Data | 236 +--------+------------+ +----------+--------+------------+ 238 +--------+------------+ +----------+--------+------------+ 239 |IPv4 Hdr| Data | <-- | IPv6 Hdr |IPv4 Hdr| Data | 240 +--------+------------+ +----------+--------+------------+ 242 /-------------------\ +-------+ /-----------------------------\ 243 | Stub Network |--|M46E-FP|--| Backbone Network | 244 | (IPv4) | +-------+ | (IPv6 only) | 245 \-------------------/ \-----------------------------/ 247 Figure 5 249 M46E-FP MUST support tunnel MTU discovery [RFC1853]. When 250 encapsulated IPv6 Packet size exceed path MTU and inner IPv4 packet 251 have the Don't Fragment bit is set, M46E-FP MUST return ICMP 252 Destination unreachable message with Type3 Code4, fragmentation 253 needed and DS set [RFC0792]. 255 In case IPv6, M46E-FP just relays IPv6 packet. 257 +----------+------------+ +----------+------------+ 258 | IPv6 Hdr | data | --> | IPv6 Hdr | data | 259 +----------+------------+ +----------+------------+ 261 +----------+------------+ +----------+------------+ 262 | IPv6 Hdr | data | <-- | IPv6 Hdr | data | 263 +----------+------------+ +----------+------------+ 265 /---------------------\ +-------+ /--------------------\ 266 | Stub Network |--|M46E-FP|--| Backbone Network | 267 | (IPv6) | +-------+ | (IPv6 only) | 268 \--------------------/ \---------------------/ 270 Figure 6 272 By IPv4 over IPv6 function, M46E-FP make backbone network to IPv6 273 only. 275 4.2. M46A architecture 277 M46A is a IPv6 address used in outer IPv6 header which encapsulate 278 IPv4 packet by M46E-FP. M46A is described in M46A 279 [I-D.draft-matsuhira-m46a]. 281 Figure 7 shows M46A address architecture 283 | 96 - m bits | m bits | 32 bits | 284 +-----------------------+--------------------------+--------------+ 285 | M46A prefix | IPv4 network plane ID | IPv4 address | 286 +-----------------------+--------------------------+--------------+ 288 Figure 7 290 M46A consists of three parts as follows. 292 M46A prefix 294 M46A prefix. This value is fixed value and preconfigured to all 295 M46E-FP in the networks. 297 IPv4 network plane ID 299 IPv4 network plane ID is an identifier of IPv4 network stack over 300 IPv6 backbone network. This value is preconfigured depend on the 301 M46E-FP belong which IPv4 network plane. For more detail see 302 Section 5. 304 IPv4 address 306 IPv4 address in inner IPv4 packet. 308 M46A is resolved copying IPv4 address in inner IPv4 packet, and 309 preconfigured values, M46A prefix and IPv4 network plane ID. 311 4.3. Route Advertisement 313 M46E-FP converts stub network's IPv4 route to M46E-FP IPv6 route and 314 advertises to backbone network. And reverse direction, M46E-FP 315 converts M46E-FP IPv6 route to IPv4 route, that advertises other IPv4 316 stub networks. 318 The IPv4 route for stub network is map to M46E-FP IPv6 route one to 319 one, so number of route of IPv4 is same as number of route of M46E-FP 320 IPv6 route. Total number of route is same as when backbone network 321 operate dual stack, without M46E-FP. 323 In stub network, usual dynamic routing protocol for IPv4 and IPv6 can 324 be used such as RIPv2 [RFC2453], RIPng [RFC2080], OSPFv2 [RFC2328], 325 OSPFv3 [RFC2740] and IS-IS [RFC1195][RFC5308]. Similarly, in 326 backbone network, usual dynamic routing protocol for IPv6 can be used 327 such as RIPng [RFC2080], OSPFv3 [RFC2740] and IS-IS [RFC5308] . 329 If want using default route, default M46E-FP advertise the route 330 [M46E-FP address prefix/( 96 - m )] as default route. If want using 331 different default route by IPv4 network plane ID, default M46E-FP in 332 IPv4 network plane #1 advertise the route [ M46E-FP address prefix + 333 IPv4 network plane ID #1 / 96] as default route. (Figure 10) in 334 Section 7 show the example using default route. 336 5. Stacking IPv4 Networks 338 M46E-FP can provide VPN like service to stub networks by using 339 different IPv4 network plane ID value. 341 If backbone network operator provide IPv4 privates network service to 342 Organization A, backbone network operator sets IPv4 network plane ID 343 value =1 to the M46E-FP which connects stub network of organization 344 A. If there are five stub network of organization A, backbone 345 network operator sets same IPv4 network plane ID = 1, to five M46E- 346 FPs which connect stub network of organization A. If there are one 347 hundred stub network of organization B, backbone network operator 348 sets same IPv4 network plane ID = 2, to one hundred M46E-FPs which 349 connect stub network of organization B. If a new stub network in 350 organization B join, backbone network operator configures same IPv4 351 network plane ID = 2, to the new stub network only, which connect 352 stub network of organization B, and no configuration is needed to one 353 hundred M46E-FPs which are already connected. 355 Such configuration, that means same stub network group to same IPv4 356 network plane ID value, is simple and easy to understand, so, it is 357 expected that possibility of misconfiguration is very low. And also, 358 number of configuration is minimum, that mean, number of 359 configuration is same as number of stub networks, and add new stub 360 network, configure to new one only. 362 Describe above, M46E-FP can provide VPN like service, for example, 363 Intranet or extranet. And, after IPv4 global address running out, 364 some service provider may want to reuse IPv4 private address. M46E- 365 FP can provide such IPv4 private address networks over single IPv6 366 backbone network. By M46E-FP, some service providers may reuse IPv4 367 private address. 369 6. Redundancy of M46E-FP 371 M46E-FP brings no limit for redundancy. Figure 8 shows such example 372 in case two connection between backbone network and stub network. 373 Number of link between backbone network and stub network is not 374 limited, and different type of link can be used, for example, for 375 wire and wireless. 377 Configuration of M46E-FPs, which connect same stub network, is same. 378 That mean same M46E-FP prefix and same IPv4 network plane ID value. 380 /---------------------------------------------------\ 381 | | 382 | Backbone Network | 383 | (IPv6 only) | 384 | | 385 \---------------------------------------------------/ 386 | | | | 387 +-------+ +-------+ +-------+ +-------+ 388 |M46E-FP| |M46E-FP| |M46E-FP| |M46E-FP| 389 +-------+ +-------+ +-------+ +-------+ 390 | | | | 391 /---------------------\ /---------------------\ 392 | | | | 393 | Stub Network | | Stub Network | 394 | (IPv4 only) | | (Dual Stack) | 395 | | | | 396 \---------------------/ \---------------------/ 398 Figure 8 400 7. Example of M46E-FP Operation 402 7.1. Basic M46E-FP Operation 404 Figure 9 shows M46E-FP operation which does not use IPv4 network 405 plane ID. In this example, two stub network is connected to backbone 406 network via M46E-FP. One stub network is 10.1.1.0/24 sub network, 407 and the other is 10.1.2.0/24 sub network. 409 When M46E-FP receives IPv4 route advertisement, then M46E-FP convert 410 this IPv4 route to IPv6 route by address resolution to M46E-FP 411 address, and advertise this IPv6 route to backbone network. When 412 M46E-FP receives IPv6 route advertisements, then M46E-FP converts 413 this IPv6 route to IPv4 route if this IPv6 route is match M46E-FP 414 address ( same prefix with M46E-FP), and advertise this IPv4 route to 415 stub network. 417 In this example. IPv4 route, 10.1.1.0/24 is converted to IPv6 route, 418 :10.1.1.0/120,and IPv4 route, 10.1.2.0/24 is converted 419 to IPv6 route, :10.1.2.0/120 at M46E-FP from stub 420 network to backbone network. And, from backbone network to stub 421 network, IPv6 route, :10.1.1.0/120 is converted to 422 IPv4 route, 10.1.1.0/24, and IPv6 route, :10.1.2.0/120 423 is converted to IPv4 route, 10.1.2.0/24. 425 /-------------\ +-----+ /------------\ +-----+ /-------------\ 426 |Stub Network | | | | Backbone | | | |Stub Network | 427 |(10.1.1.0/24)|--|M46E |--| Network |--|M46E |--|(10.1.2.0/24)| 428 | | | -FP | |(IPv6 only) | | -FP | | | 429 \-------------/ +-----+ \------------/ +-----+ \-------------/ 431 [10.1.1.0/24] ---> [:10.1.1.0/120] ---> [10.1.1.0/24] 432 [10.1.2.0/24] <--- [:10.1.2.0/120] <--- [10.1.2.0/24] 434 +---------+----+ +---------+----+----+ +---------+----+ 435 | data |IPv4| --> | data |IPv4|IPv6| --> | data |IPv4| 436 +---------+----+ +---------+----+----+ +---------+----+ 437 src: 10.1.1.1 src: :10.1.1.1 src: 10.1.1.1 438 dst: 10.1.2.1 dst: :10.1.2.1 dst: 10.1.2.1 440 Figure 9 442 Figure 10 shows the example using default route. Default route is 443 useful in case most packets are routed same path. Typically, access 444 network is one of the example. Although using default route, 445 communication between stub networks can be done. Communication 446 between host 10.1.1.1 and host 10.1.2.1 can be done inside in access 447 network, and does not pass over default M46E-FP. 449 /------------\ 450 | | 451 /-------------\ +-----+ | | +-----+ /-------------\ 452 | Backbone | | | | Access | | | |Stub Network | 453 | Network |--|M46E |--| Network |--|M46E |--|(10.1.1.0/24)| 454 | | | -FP | |(IPv6 only) | | -FP | | | 455 \-------------/ +-----+ | | +-----+ \-------------/ 456 (default) | <--[:10.1.1.0/120] 457 [/96] --> | 458 | | 459 | | +-----+ /-------------\ 460 | | | | |Stub Network | 461 | |--|M46E |--|(10.1.2.0/24)| 462 | | | -FP | | | 463 | | +-----+ \-------------/ 464 | <--[:10.1.2.0/120] 465 | | 466 | | 467 | | +-----+ /-------------\ 468 | | | | |Stub Network | 469 | |--|M46E |--|(10.1.3.0/24)| 470 | | | -FP | | | 471 | | +-----+ \-------------/ 472 | <--[:10.1.3.0/120] 473 | | 474 \------------/ 476 Figure 10 478 7.2. M46E-FP Operation with plane ID 480 Figure 11 shows M46E-FP operation which uses IPv4 network plane ID. 481 In this example, there are two planes, and two stub network in each 482 plane is connected to backbone network via M46E-FP. In each plane, 483 one stub network is 10.1.1.0/24 sub network, and the other is 484 10.1.2.0/24 sub network, that means same IPv4 address is used in 485 different plane. 487 When M46E-FP receives IPv4 route advertisements, then M46E-FP 488 converts this IPv4 route to IPv6 route by address resolution to M46E- 489 FP address, and advertise this IPv6 route to backbone network. When 490 M46E-FP receives IPv6 route advertisements, then M46E-FP converts 491 this IPv6 route to IPv4 route if this IPv6 route is match M46E-FP 492 address ( same prefix with M46E-FP), and advertises this IPv4 route 493 to stub network. 495 In this example in plane #1. IPv4 route, 10.1.1.0/24 is converted to 496 IPv6 route, <#1>:10.1.1.0/120,and IPv4 route, 497 10.1.2.0/24 is converted to IPv6 route, <#1>:10.1.2.0/120 at M46E-FP from stub network to backbone 499 network. And, from backbone network to stub network, IPv6 route, 500 <#1>:10.1.1.0/120 is converted to IPv4 route, 501 10.1.1.0/24, and IPv6 route, <#1>:10.1.2.0/120 is 502 converted to IPv4 route, 10.1.2.0/24. 504 And also, In this example in plane #2. IPv4 route, 10.1.1.0/24 is 505 converted to IPv6 route, <#2>:10.1.1.0/120,and IPv4 506 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 508 network. And, from backbone network to stub network, IPv6 route, 509 <#2>:10.1.1.0/120 is converted to IPv4 route, 510 10.1.1.0/24, and IPv6 route, <#2>:10.1.2.0/120 is 511 converted to IPv4 route, 10.1.2.0/24. 513 In IPv6 space, address <#1>:10.1.1.1 and address 514 <#2>:10.1.1.1 are different address, route <#1>:10.1.1.0/120 and route <#2>:10.1.1.0/120 516 are different route, although in IPv4 space, address 10.1.1.1 in 517 plane #1 and 10.1.1.1 in plane#2 are same address, route 10.1.1.0/24 518 in plane#1 and route 10.1.1.0/24 in plane#2 are same route. 520 /------------\ 521 ...................|............|............................ 522 : /-------------\ +-----+ | | +-----+ /-------------\ : 523 : | Stub Network| | | | | | | | Stub Network| : 524 : |(10.1.1.0/24)|--|M46E |--| Backbone |--|M46E |--|(10.1.2.0/24)| : 525 : | | | -FP | | Network | | -FP | | | : 526 : \-------------/ +-----+ |(IPv6 only) | +-----+ \-------------/ : 527 :...........................|............|...........................: 528 | | 529 ...................|............|............................ 530 : /-------------\ +-----+ | | +-----+ /-------------\ : 531 : | Stub Network| | | | | | | | Stub Network| : 532 : |(10.1.1.0/24)|--|M46E |--| |--|M46E |--|(10.1.2.0/24)| : 533 : | | | -FP | | | | -FP | | | : 534 : \-------------/ +-----+ | | +-----+ \-------------/ : 535 :...........................|............|...........................: 536 \------------/ 538 <> 540 [10.1.1.0/24] --> [<#1>:10.1.1.0/120] --> [10.1.1.0/24] 541 [10.1.2.0/24] <-- [<#1>:10.1.2.0/120] <-- [10.1.2.0/24] 543 +---------+----+ +---------+----+----+ +---------+----+ 544 | data |IPv4| --> | data |IPv4|IPv6| --> | data |IPv4| 545 +---------+----+ +---------+----+----+ +---------+----+ 546 src: 10.1.1.1 src: <#1>:10.1.1.1 src: 10.1.1.1 547 dst: 10.1.2.1 dst: <#1>:10.1.2.1 dst: 10.1.2.1 549 <> 551 [10.1.1.0/24] --> [<#2>:10.1.1.0/120] --> [10.1.1.0/24] 552 [10.1.2.0/24] <-- [<#2>:10.1.2.0/120] <-- [10.1.2.0/24] 554 +---------+----+ +---------+----+----+ +---------+----+ 555 | data |IPv4| --> | data |IPv4|IPv6| --> | data |IPv4| 556 +---------+----+ +---------+----+----+ +---------+----+ 557 src: 10.1.1.1 src: <#2>:10.1.1.1 src: 10.1.1.1 558 dst: 10.1.2.1 dst: <#2>:10.1.2.1 dst: 10.1.2.1 560 Figure 11 562 Figure 12shows the example using default route with IPv4 network 563 plane. In this case, default M46E-FP may configure different by each 564 IPv4 network plane. 566 /------------\ 567 ...................|............|............................ 568 : /-------------\ +-----+ | | +-----+ /-------------\ : 569 : | Backbone | | | | | | | | Stub Network| : 570 : | Network |--|M46E |--| Access |--|M46E |--|(10.1.1.0/24)| : 571 : | | | -FP | | Network | | -FP | | | : 572 : \-------------/ +-----+ |(IPv6 only) | +-----+ \-------------/ : 573 : (default) | <--[<#1>:10.1.1.0/120] : 574 : [<#1>/96] --> | : 575 : | | : 576 : | | : 577 : | | +-----+ /-------------\ : 578 : | | | | | Stub Network| : 579 : | |--|M46E |--|(10.1.2.0/24)| : 580 : | | | -FP | | | : 581 : | | +-----+ \-------------/ : 582 : | <--[<#1>:10.1.2.0/120] : 583 :...........................|............|...........................: 584 | | 585 ...................|............|............................ 586 : /-------------\ +-----+ | | +-----+ /-------------\ : 587 : | Backbone | | | | | | | | Stub Network| : 588 : | Network |--|M46E |--| |--|M46E |--|(10.1.1.0/24)| : 589 : | | | -FP | | | | -FP | | | : 590 : \-------------/ +-----+ | | +-----+ \-------------/ : 591 : (default) | <--[<#2>:10.1.1.0/120] : 592 : [<#2>/96] --> | : 593 : | | : 594 : | | : 595 : | | +-----+ /-------------\ : 596 : | | | | | Stub Network| : 597 : | |--|M46E |--|(10.1.2.0/24)| : 598 : | | | -FP | | | : 599 : | | +-----+ \-------------/ : 600 : | <--[<#2>:10.1.2.0/120] : 601 :...........................|............|...........................: 602 | | 603 \------------/ 605 Figure 12 607 8. Characteristic 609 M46E-FP has following useful characteristics. 611 o Reduce backbone network operation cost with IPv6 single stack ( at 612 least less than Dual Stack) 614 o Can allocate IPv4 address to stub networks, which used in backbone 615 network before installing M46E-FP 617 o Less configuration 619 o No need for special protocol 621 o No dependent Layer 2 network 623 o Can Stack IPv4 Private networks 625 o Easy stop IPv4 operation in stub network for future ( just remove 626 M46E-FP) 628 o Provide redundancy 630 9. IANA Considerations 632 This document makes no request of IANA. 634 Note to RFC Editor: this section may be removed on publication as an 635 RFC. 637 10. Security Considerations 639 M46E-FP use automatic Encapsulation / Decapsulation technologies. 640 Security consideration related tunneling technologies are discussed 641 in RFC2893[RFC2893], RFC2267[RFC2267], etc. 643 11. References 645 11.1. Normative References 647 [I-D.draft-matsuhira-m46a] 648 Matsuhira, N., "Multiple IPv4 - IPv6 mapped IPv6 address", 649 June 2019. 651 [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, 652 RFC 792, DOI 10.17487/RFC0792, September 1981, 653 . 655 [RFC1853] Simpson, W., "IP in IP Tunneling", RFC 1853, 656 DOI 10.17487/RFC1853, October 1995, 657 . 659 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 660 Requirement Levels", BCP 14, RFC 2119, 661 DOI 10.17487/RFC2119, March 1997, 662 . 664 11.2. References 666 [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and 667 dual environments", RFC 1195, DOI 10.17487/RFC1195, 668 December 1990, . 670 [RFC2080] Malkin, G. and R. Minnear, "RIPng for IPv6", RFC 2080, 671 DOI 10.17487/RFC2080, January 1997, 672 . 674 [RFC2267] Ferguson, P. and D. Senie, "Network Ingress Filtering: 675 Defeating Denial of Service Attacks which employ IP Source 676 Address Spoofing", RFC 2267, DOI 10.17487/RFC2267, January 677 1998, . 679 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 680 DOI 10.17487/RFC2328, April 1998, 681 . 683 [RFC2453] Malkin, G., "RIP Version 2", STD 56, RFC 2453, 684 DOI 10.17487/RFC2453, November 1998, 685 . 687 [RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", 688 RFC 2740, DOI 10.17487/RFC2740, December 1999, 689 . 691 [RFC2893] Gilligan, R. and E. Nordmark, "Transition Mechanisms for 692 IPv6 Hosts and Routers", RFC 2893, DOI 10.17487/RFC2893, 693 August 2000, . 695 [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, 696 DOI 10.17487/RFC5308, October 2008, 697 . 699 Author's Address 700 Naoki Matsuhira 701 Fujitsu Limited 702 17-25, Shinkamata 1-chome, Ota-ku 703 Tokyo 144-8588 704 Japan 706 Phone: +81-3-3735-1111 707 Email: matsuhira@fujitsu.com