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Ati 3 Intended status: Experimental Avinta Communications, Inc. 4 Expires: June 2017 5 December 14, 2016 7 Adaptive IPv4 Address Space 8 draft-chen-ati-adaptive-ipv4-address-space-00.txt 10 Status of this Memo 12 This Internet-Draft is submitted in full conformance with the 13 provisions of BCP 78 and BCP 79. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as Internet- 18 Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html 31 This Internet-Draft will expire on June 14, 2017. 33 Copyright Notice 35 Copyright (c) 2016 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents 40 (http://trustee.ietf.org/license-info) in effect on the date of 41 publication of this document. Please review these documents 42 carefully, as they describe your rights and restrictions with respect 43 to this document. Code Components extracted from this document must 44 include Simplified BSD License text as described in Section 4.e of 45 the Trust Legal Provisions and are provided without warranty as 46 described in the Simplified BSD License. 48 Abstract 50 This document describes a solution to the Internet address depletion 51 issue through the use of an existing Option mechanism that is part of 52 the original IPv4 protocol. This proposal, named EzIP (phonetic for 53 Easy IPv4), discusses the IPv4 public address pool expansion and the 54 Internet system architecture enhancement aspects. It was originated 55 by a study called ExIP (Extended IPv4) analyzing the use of the first 56 available octet (eight bits) in the reserved private network pools 57 (10/8, 172.16/12 and 192.168/16) to achieve a moderate address space 58 expansion factor of 256 by each, while maintaining their familiar 59 operation characteristics. Along the way, a parallel yet similar 60 effort, called EnIP (Enhanced IPv4), was discovered. EnIP fully 61 utilizes the same private network pools to increase the address space 62 by a factor of 17.1M with end-to-end connectivity. EzIP is a superset 63 that proposes one unified format for not only encompassing the 64 considerations of both, but also identifying additional capabilities 65 and flexibilities. For example, EzIP may expand an IPv4 address at 66 least by a factor of 256 to as high as 256M without affecting the 67 existing IPv4 public address assignments, while still keeping intact 68 the current private networks for the 256M case if desired. The EzIP 69 is in full conformance with the IPv4 protocol, and supports not only 70 both categories of connectivity, but also their interoperability. The 71 traditional Internet traffic and the IoT operations may coexist 72 simultaneously without perturbing their existing setups, while 73 offering end-users the freedom to choose one or the other. If the 74 IPv4 public pool were reorganized, the assignable pool could be 75 multiplied by 512M or even up to 2B times with end-to-end 76 connectivity. EzIP may be deployed as a firmware enhancement to the 77 Internet edge routers or private network gateways wherever needed, or 78 simply installed as an inline adjunct module between the two, 79 enabling a seamless introduction. The 256M case establishes a 80 spherical layer of routers providing a complete interconnection 81 between the Internet and end-users. This configuration enables the 82 entire current Internet and private networks characteristics to 83 remain intact. These proposed interim facilities would afford IPv6 84 more time to orderly reach the maturity and the availability levels 85 required for delivering a long-term general service. 87 Table of Contents 89 1. Introduction...................................................4 90 1.1. Contents of this Draft....................................5 91 2. EzIP Overview..................................................6 92 2.1. EzIP Numbering Plan.......................................6 93 2.2. EzIP System Architecture.................................10 94 2.3. IP Header with Option Word...............................13 95 2.4. Examples of Option Mechanism.............................13 96 2.5. Basic EzIP Header........................................14 97 2.6. EzIP Operation...........................................16 98 2.7. Generalizing EzIP Header.................................17 99 3. EzIP Deployment Strategy......................................18 100 4. Updating Servers to Support EzIP..............................19 101 5. EzIP Enhancements.............................................20 102 6. Security Considerations.......................................24 103 7. IANA Considerations...........................................24 104 8. Conclusions...................................................24 105 9. References....................................................25 106 9.1. Normative References.....................................25 107 9.2. Informative References...................................25 108 10. Acknowledgments..............................................26 109 Appendix A EzIP System Architecture.............................27 110 A.1. EzIP System Part A.......................................27 111 A.2. EzIP System Part B.......................................27 112 A.3. EzIP System Part C.......................................28 113 A.4. EzIP System Part D.......................................29 114 Appendix B EzIP Operation.......................................31 115 B.1. Connection between EzIP-unaware IoTs.....................31 116 B.1.1. T1a Initiates a Session Request towards T4a.........31 117 B.1.2. RG1 Forwards the Packet to SPR1.....................32 118 B.1.3. SPR1 Sends the Packet to SPR4 through the Internet..33 119 B.1.4. SPR4 Sends the Packet to T4a........................34 120 B.1.5. T4a Replies to SPR4.................................35 121 B.2. Connection Between EzIP-capable IoTs..................39 122 B.2.1. T1z Initiates a Session Request towards T4z.........39 123 B.2.2. RG1 Forwards the Packet to SPR1.....................40 124 B.2.3. SPR1 Sends the Packet to SPR4 through the Internet..41 125 B.2.4. SPR4 Sends the Packet towards T4z to RG2............42 126 B.2.5. T4z Replies to SPR4.................................43 127 B.2.6. SPR4 Sends the Packet to SPR1 through the Internet..44 128 B.2.7. SPR1 Sends the Packet to RG1........................45 129 B.2.8. RG1 Forwards the Packet to T1z......................46 130 B.2.9. T1z Sends a Follow-up Packet to RG1.................47 131 B.3. Connection Between EzIP-unaware and EzIP-capable IoTs....47 132 B.3.1. T1a initiates a request to T4z......................47 133 B.3.2. T1z initiates a request to T4a......................48 134 Appendix C Internet Transition Considerations...................49 135 C.1. EzIP Implementation......................................49 136 C.2. SPR Operation Logic......................................50 137 C.3. RG Enhancement...........................................51 139 1. Introduction 141 For various reasons, there is a large demand for IP addresses. It 142 would be useful to have a unique address for each Internet device, 143 such that if desired, any device may call any other. The Internet of 144 Things (IoT) would also be able to make use of more routable 145 addresses if they were available. Currently, these are not possible 146 with the existing IPv4 facility. 148 By Year 2020, the population and number of IoTs are expected to reach 149 7.6 billion and 50 billion respectively, according to a recent Cisco 150 online paper [1]. 152 The IPv4 dot-decimal address format, consisting of four octets each 153 made of 8 binary bits, results in the maximum number of assignable 154 public addresses of 4.295 billion (calculated by 256 x 256 x 256 x 155 256, to be 4,294,967,296 - decimal exact). Using the binary / 156 shorthand notation of 64K representing 256 x 256 (decimal 65,536), 157 the full IPv4 address pool of 64K x 64K may be expressed as 4,096M, 158 or 4.096B. Clearly, the demand is more than 13 times over the 159 inherent capability available from the supply. 161 IPv6 with 128-bit hexadecimal address format offers a potential 162 solution to this problem, but its global adoption appears to face 163 certain challenges [2], [3]. Network Address and Port Translation 164 (NAPT - commonly known simply as NAT) on private networks together 165 with Carrier Grade NAT (CGNAT) over the Internet have been providing 166 the interim solutions thus far. However, NAT modules slow down 167 routers due to the state-table look-up process. As well, they only 168 allow an Internet session be initiated by their respective own 169 clients, impeding the end-to-end setup requests from remote devices 170 that certain IoT operations desire. 172 If the IPv4 capacity could be expanded to eliminate this address pool 173 deficiency while maintaining the familiar established operation 174 conventions, and perhaps even offers reasonable reserve, the urgency 175 will be relaxed long enough for the IPv6 to mature on its own pace. 177 To increase the Internet public address pool, there have been various 178 proposals in the past. Among them, two recent efforts in particular 179 are referenced by this draft, namely ExIP and EnIP. The ExIP [4] 180 study focuses on reclaiming part of a reserved private network 181 address block, for example the third octet of 192.168/16, to be 182 publicly routable at the edge of the Internet. By making use of this 183 octet as semi-public address, the number of assignable public 184 addresses is increased by a factor of 256 to become 1049B which is 185 more than 20 times of the expected IoTs. This address expansion could 186 be implemented in an inline module called Semi-Public Router (SPR) 187 collocated with the Internet Edge Router (ER). Of course, the size of 188 the resultant private networks will be reduced accordingly. 190 The Enhanced IP (EnIP) [5] project proposes to increase the available 191 IPv4 public address space by a factor of 17.1M. Like IPv6, EnIP 192 results in full end-to-end connectivity among the enhanced addresses. 193 The EnIP implementation module, "NAT and EnIPNAT/translator", 194 replacing existing private network gateway, is very similar to the 195 SPR. 197 EzIP merges these two schemes into one uniform solution. Neither 198 Internet Core (/ backbone) Router (CR), nor private network Routing 199 Gateway (RG) needs to handle the Options added to the resultant IP 200 header, since their designs recognize and preserve this Option 201 mechanism, yet are not programmed to process the specific EzIP 202 information. Even the Edge Routers (ER) may stay unchanged, if the 203 SPR is deployed with the adjunct configuration during the 204 introductory phase. 206 The assignable IPv4 compatible public address pool may be expanded 207 significantly more upon incorporating other available IPv4 resources 208 by the EzIP technique, as discussed in the latter part of this 209 document. 211 1.1. Contents of this Draft 213 The rest of this draft begins with outlining the EzIP numbering plan. 214 A modified IP header called EzIP header is introduced for carrying 215 the EzIP address data in the Option words. The overview of the 216 Internet architecture as the result of being expanded by the EzIP 217 scheme, the EzIP header transitions through various routers and the 218 operation considerations are discussed next, with details presented 219 in Appendices A, B and C, respectively. Utilizing the EzIP approach, 220 a range of possibilities of expanding the publicly assignable IPv4 221 address pool as well as enhancing the Internet operation flexibility 222 are then described. 224 2. EzIP Overview 226 2.1. EzIP Numbering Plan 228 The ExIP technique which is the foundation of the EzIP plan began 229 with making use of the reserved private network address pools in very 230 much the same manner as Private Automatic Branch eXchange (PABX) 231 telephone switching machines utilizing locally assigned "extension 232 numbers" to expand the Public Switched Telephone Network (PSTN) 233 capacity by replicating a public telephone line to multitudes of 234 reusable private telephone numbers, each to identify a local 235 instrument. At the first sight, this may seem odd, because the 236 extension numbers of a PABX belong to a separate set from that of the 237 public telephone numbers, while private network IP address is a 238 specific subset reserved from the overall IPv4 pool that is otherwise 239 all public. However, recognizing that neither of the latter two is 240 allowed to operate in the other's domain suggests that the proposed 241 EzIP numbering system indeed may mirror the telephony case. In fact, 242 the very basic form of the EzIP numbering is to make explicit the 243 familiar subnetting process of 192.168/16 that has been performed 244 routinely by consumer RGs (Residential / Routing Gateways) on 245 residential premises for a long time. 247 2.1.1. To facilitate the following discussions, the 32 bits in a 248 private network address notation are divided into three parts, namely 249 Network, Extension and IoT No.'s as shown in Figure 1 below. 251 0 1 2 3 252 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 1 253 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 | Network No. - Extension No. : IoT No. | 255 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 257 Figure 1 EzIP Address Notation (Generic) 259 The number of bits in the Extension No. part determines the 260 multiplication factor to be applied by the EzIP process. The trailing 261 IoT No. bits determine the size of the resultant private network. The 262 Network No. part is the specific binary value of the remaining 263 leading bits (the prefix) identifying an address block that will be 264 reserved from the public IPv4 pool. 266 2.1.2. Following the general concept of subnetting, the unit for 267 expanding an address does not need to be restricted to the boundary 268 of an octet. This allows potentially finer grain resolution. 270 2.1.3. How to utilize the 32 bits leads to tradeoffs among EzIP 271 operation characteristics. For example, maintaining the private 272 network properties or establishing the end-to-end connectivity is 273 just a matter of whether there are bits reserved for the IoT No. 275 2.1.4. This notation may be used to present two general categories 276 of EzIP address types: 278 A. To retain the private network characteristics, the EzIP 279 subnetting makes use of only the first available octet. For the 280 common three private network address pools, we will have the 281 following: 283 In Figure 2, 8 bits are available for IoT No., resulting in private 284 networks each capable of 256 IoTs. 286 0 1 2 3 287 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 1 288 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 289 | 192.168 - Extension No. : IoT No. | 290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 292 Figure 2 EzIP-1 (8 bits of 192.168/16 semi-publicly addressable) 294 In Figure 3, 12 bits are available for IoT No., resulting in private 295 networks each capable of 4K IoTs. 297 0 1 2 3 298 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 1 299 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 300 | 172.16 - Extension No. : IoT No. | 301 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 303 Figure 3 EzIP-2 (8 bits of 172.16/12 semi-publicly addressable) 305 In Figure 4, 16 bits are available for IoT No., resulting in private 306 networks each capable of 64K IoTs. 308 0 1 2 3 309 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 1 310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 311 | 10 - Extension No. : IoT No. | 312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 314 Figure 4 EzIP-3 (8 bits of 10/8 semi-publicly addressable) 316 B. To allow direct access from the Internet, EzIP makes use of all 317 available bits in a reserved private network address as Extension 318 No., leaving no bit for the IoT No. The resultant private network 319 will have no RG, but only one IoT that is directly connected to the 320 Internet: 322 In Figure 5, 16 bits are assigned for Extension No., resulting in 64K 323 IoTs directly addressable from the Internet. 325 0 1 2 3 326 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 1 327 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 328 | 192.168 - Extension No. | 329 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 331 Figure 5 EzIP-4 (16 bits of 192.168/16 semi-publicly addressable) 333 In Figure 6, 20 bits are assigned for Extension No., resulting in 334 1M IoTs directly addressable from the Internet. 336 0 1 2 3 337 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 1 338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 339 | 172.16 - Extension No. | 340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 342 Figure 6 EzIP-5 (20 bits of 172.16/12 semi-publicly addressable) 344 In Figure 7, 24 bits are assigned for Extension No., resulting in 16M 345 IoTs directly addressable from the Internet. 347 0 1 2 3 348 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 1 349 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 350 | 10 - Extension No. | 351 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 353 Figure 7 EzIP-6 (24 bits of 10/8 semi-publicly addressable) 355 For cross reference purpose, EzIP-1 through EzIP-3 are the same 356 numbering types used by the ExIP study, while EzIP-4 through EzIP-6 357 are used by the EnIP project. 359 Figure 8 summarizes the number of possible publicly and privately 360 assignable addresses for each original IPv4 public address under 361 different configurations. 363 | 192.168/16 | 172.16/12 | 10/8 | 364 ==============+===============+================+==============+ 365 Basic IPv4 | | | | 366 --------------+---------------+----------------+--------------+ 367 Address Bits* | 32 | 32 | 32 | 368 --------------+---------------+----------------+--------------+ 369 Public | 1 | 1 | 1 | 370 Private | 64K | 1M | 16M | 371 ==============+===============+================+==============+ 372 (ExIP) | EzIP-1 | EzIP-2 | EzIP-3 | 373 --------------+---------------+----------------+--------------+ 374 Address Bits* | 40 | 40 | 40 | 375 --------------+---------------+----------------+--------------+ 376 Semi-Public | 256 | 256 | 256 | 377 Private | 256 | 4K | 64K | 378 ==============+===============+================+==============+ 379 (EnIP) | EzIP-4 | EzIP-5 | EzIP-6 | 380 --------------+---------------+----------------+--------------+ 381 Address Bits* | 48 | 52 | 56 | 382 --------------+---------------+----------------+--------------+ 383 Public | 64K | 1M | 16M | 384 Private | 1 | 1 | 1 | 385 ==============+===============+================+==============+ 386 Notes: 388 a. * -- Effective Overall Public Address Length 389 b. For each Public-Private pair, the numbers of addresses are 390 multiplicative, not additive. 392 Figure 8 Basic IPv4 Address Expansion Configurations 394 2.2. EzIP System Architecture 396 With six basic EzIP expansion types, it is difficult to include them 397 all in one single system architecture diagram. A complete set of 398 system architectural diagrams is presented in Appendix A. To 399 facilitate the presentation, a partial system diagram covering only 400 the 192.168/16 (EzIP-1 and EzIP-4) portion as presented in Figure 9 401 below will be utilized for the discussions that follow. 403 +------+ 404 Web Server | WS0z | 405 +--+---+ 406 |69.41.190.145 407 | 408 | +-----+ 409 +--+ ER0 | 410 +--+--+ 411 | 412 +------+-------+ 413 +-------+ Internet +--------+ 414 | |(Core Routers)| | 415 +--+--+ +--------------+ +--+--+ 416 +-----+ ER1 | +-----+ ER4 | 417 | +-----+ | +-----+ 418 | | 419 EzIP-1 |69.41.190.110 EzIP-4 |69.41.190.148 420 +--+--+ +--+--+ 421 +-----------+ +-------+ +---------+ +------+ 422 | +-----+ SPR1| | | +-----+ SPR4+--+ | 423 | | +-----+ | | | +-----+ | | 424 | 192.168.2.0 ... 192.168.255.0 | | | | 425 +-----+ |...| |...| 426 |192.168.1.0 | | +---------+ | 427 +--+--+ | | | | 428 +---+ RG1 +--+ 192.168.0.1 | | 192.168.255.255 429 | +-----+ | | | 430 | Premises 1 | +----------+ | 431 | | | Premises 4 | 432 |192.168.1.3 |192.168.1.9 |192.168.4.10 |192.168.4.40 433 +--+--+ +--+--+ +--+--+ +--+--+ 434 | T1a | .... | T1z | | T4a | ....... | T4z | 435 +-----+ +-----+ +-----+ +-----+ 437 Figure 9 EzIP System Architecture-A (192.168/16 Portion) 439 +--------------------------+-----------------+----------------+ 440 | | Basic IPv4 | EzIP-capable | 441 +--------------------------+-----------------+----------------+ 442 | Internet Edge Router (ER)| ER0, ER1, ER4 | ------------ | 443 +--------------------------+-----------------+----------------+ 444 | Internet of Things (IoT) | T1a, T4a | T1z, T4z | 445 +--------------------------+-----------------+----------------+ 446 | Routing Gateway (RG) | RG1 | ------------ | 447 +--------------------------+-----------------+----------------+ 448 | Semi-Public Router (SPR) | ------------- | SPR1, SPR4 | 449 +--------------------------+-----------------+----------------+ 450 | Web Server (WS) | ------------- | WS0z | 451 +--------------------------+-----------------+----------------+ 453 Figure 10 EzIP-1 & EzIP-4 Components 455 2.2.1. Referring to the left portion labeled EzIP-1 of Figure 9, 456 instead of assigning each premises a public IPv4 address as in the 457 current practice, an SPR like SPR1, is inserted between an Internet 458 Edge Router (ER1) and its connections to private network Routing 459 Gateways like RG1, for utilizing the third octet, such as 460 192.168.nnn/24 (nnn = 0 through 255) to identify respective entities. 461 The RG1 serves either a LAN or a HAN. On each LAN / HAN, the fourth 462 octet "mmm" of 192.168.nnn.mmm/32 continues to be used by the RG1 to 463 identify the IoTs it serves. This is how common RGs are being 464 configured today anyway (Factory default values of nnn are usually 0, 465 1, 2, 10, etc.) 467 2.2.2. The right portion of Figure 9 is labeled EzIP-4. Here SPR4 468 assigns the full range of the available 192.168/16 IP addresses (the 469 third and fourth octets) individually to T4a through T4z. 470 Consequently, these IoTs are directly accessible from any remote 471 device on the Internet. 473 2.2.3. Since the existing physical connections to subscriber's 474 premises do appear at the ER, it is natural to have SPRs be 475 collocated with their ER. It follows that the simple routing function 476 provided by the new SPR modules may be absorbed into the ER through a 477 straightforward operational firmware enhancement. Consequently, the 478 public - private demarcation line will remain at the RG where 479 currently all utility services enter a subscriber's premises. 481 2.2.4. To identify each of these devices, we may use a three part 482 address format "IPv4 - Semi-Public: TCP Port No.". The following is 483 how each of the IoTs in Figure 9 may be identified. 485 RG1: 69.41.190.110-192.168.1.0 487 T1a: 69.41.190.110-192.168.1.0:3 489 T1z: 69.41.190.110-192.168.1.0:9 491 T4a: 69.41.190.148-192.168.4.10 493 T4z: 69.41.190.148-192.168.4.40 495 Note that to simplify the presentation, it is assumed at this 496 juncture that the conventional TCP (Transmission Control Protocol) 497 [6] Port Number, normally assigned to T1a and T1z by RG1's NAT module 498 upon initiating a session, equals to the fourth octet of that IoT's 499 private IP address that is assigned by the RG1's DHCP (Dynamic Host 500 Configuration Protocol) [7] module as ":3" and ":9", respectively. 501 Such numbers are unique within each respective private network. They 502 are adequate for the discussion purpose here. However, considering 503 security, as well as allowing each IoT to have multiple simultaneous 504 sessions, etc., this direct correlation shall be avoided in actual 505 practices by following the NAT operation conventions as depicted by 506 the examples in Error! Reference source not found.. 508 2.3. IP Header with Option Word 510 To transport the EzIP Extension No., we will make use of the Option 511 word in the IP header as defined in Figure 9 of [RFC791] [8]. This 512 mechanism has been used for various cases in the past. Since they 513 were mostly for utility or experimental purposes, however, their 514 formats may be remote from the incident discussion. 516 2.4. Examples of Option Mechanism 518 The following two cases specifically deal with the address pool 519 issues. They are referenced here to facilitate the appreciation of 520 the Option mechanism. 522 A. EIP (Extended Internet Protocol) - [RFC1385] [9] (Assigned but 523 now deprecated Option Number = 17) by Z. Wang: This approach 524 attempted to add a new network layer on top of the existing Internet 525 for increasing the addressable space. Although equipment near the 526 end-user would stay unchanged, equipments around the Internet Core 527 Routers (CR) apparently had to go through rather involved upgrade 528 procedures. 530 B. EnIP (Enhanced IPv4) - Internet Draft [5] (temporarily 531 utilizing Option Number = 26) by W. Chimiak: This work makes use of 532 the reserved private network addresses to extend the public pool by 533 trading the private network operation for end-to-end connectivity. 534 The EnIP and ExIP approaches closely resemble each other. 536 2.5. Basic EzIP Header 538 The basic EzIP header format uses the Option ID field to convey the 539 value of the "Network No." as well as the length of the "Extension 540 No.". This header has the capacity to handle up to two octets of the 541 "Extension No." on either end of a connection. 543 0 1 2 3 544 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 1 545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 546 1 |Version|IHL (7)|Type of Service| Total Length (28) | 547 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 548 2 | Identification |Flags| Fragment Offset | 549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 550 3 | Time to Live | Protocol | Header Checksum | 551 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 552 4 | Source Host Number | 553 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 554 5 | Destination Host Number | 555 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 556 | EzIP ID | EzIP | Extended | Extended | 557 6 | (Source) | Option Length | Source | Source | 558 | (------) | (4) | No.-1 | No.-2 | 559 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 560 | EzIP ID | EzIP | Extended | Extended | 561 7 | (Destination) | Option Length | Destination | Destination | 562 | (------) | (4) | No.-1 | No.-2 | 563 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 565 Figure 11 Basic EzIP Header (Two Octet) 567 To transport an IP header for T4z at the Source end and RG1 at the 568 Destination end, Figure 12 depicts an EzIP header example: 570 0 1 2 3 571 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 1 572 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 573 1 |Version|IHL (7)|Type of Service| Total Length (28) | 574 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 575 2 | Identification |Flags| Fragment Offset | 576 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 577 3 | Time to Live | Protocol | Header Checksum | 578 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 579 4 | Source Host Number (69.41.190.148) | 580 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 581 5 | Destination Host Number (69.41.190.110) | 582 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 583 | EzIP-4 | EzIP | Extended | Extended | 584 6 | (Source) | Option Length | Source | Source | 585 | (0X9A) | (4) | No. (4) | No. (40) | 586 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 587 | EzIP-1 | EzIP | Extended | End of | 588 7 | (Destination) | Option Length | Destination | Option List | 589 | (0x9B) | (3) | No. (1) | (00000000) | 590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 592 Figure 12 EzIP Header Example 1 594 Note that the Option IDs 0x9A (Option Number = 26) and 0x9B (Option 595 Number = 27), both representing Network No. 192.168/16 while 596 conveying the Extension No.'s being two and one octet, respectively, 597 in the above figure, are arbitrarily chosen from the currently 598 available Option Numbers list [10]. Since RG1 extension No. has only 599 one octet, the "End of Option list" Option is used to fill up word 7. 601 If the transmission direction is reversed, types of EzIP extension 602 used by the Source and the Destination will be interchanged as well. 603 The unused octet will now be at the end of word 6. The "No Operation" 604 Option should be used as the filler shown in Figure 13: 606 0 1 2 3 607 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 1 608 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 609 1 |Version|IHL (7)|Type of Service| Total Length (28) | 610 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 611 2 | Identification |Flags| Fragment Offset | 612 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 613 3 | Time to Live | Protocol | Header Checksum | 614 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 615 4 | Source Host Number 69.41.190.110) | 616 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 617 5 | Destination Host Number (69.41.190.148) | 618 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 619 | EzIP ID | EzIP | Extended | No | 620 6 | (Source) | Option Length | Source | Operation | 621 | (0X9B) | (3) | No. (1) | (00000001) | 622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 623 | EzIP ID | EzIP | Extended | Extended | 624 7 | (Destination) | Option Length | Destination | Destination | 625 | (0x9A) | (4) | No. (4) | No. (40) | 626 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 628 Figure 13 EzIP Header Example 2 630 2.6. EzIP Operation 632 With half a dozen of EzIP types, it would be very tedious and 633 distracting to go through all combinations of IP header 634 configurations and their transitions through the network. To convey 635 the general scheme, Error! Reference source not found. presents 636 examples of EzIP header transitions through routers among IoTs having 637 EzIP-1 and EzIP-4 types of addresses, with and without EzIP 638 capability. 640 To introduce the EzIP approach into an environment where EzIP-unaware 641 IoTs like T1a and T4a will be numerous for a long time to come, a SPR 642 must be able to follow certain decision rules to determine which type 643 of service to provide for achieving a smooth transition. Appendix C 644 outlines such logic and related considerations. 646 2.7. Generalizing EzIP Header 648 2.7.1. The basic EzIP header shown in Figure 11 with up to two 649 octet Extension No. format is not capable of EzIP-5 and EzIP-6 types 650 with 20 and 24 bit, respectively. One extra octet is needed on each 651 end of such a connection. An additional word in the header, however, 652 will have two octets unused. To take advantage of this spare 653 resource, we might as well consider a header format shown in Figure 654 14 that can transport the full 4 octet (32 bit) extension addresses 655 of both ends. This is similar as the EnIP header [5], except more 656 flexible by allowing EzIP type being independent of that at the other 657 end. 659 0 1 2 3 660 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 1 661 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 662 1 |Version|IHL (8)|Type of Service| Total Length (32) | 663 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 664 2 | Identification |Flags| Fragment Offset | 665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 666 3 | Time to Live | Protocol | Header Checksum | 667 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 668 4 | Source Host Number | 669 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 670 5 | Destination Host Number | 671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 672 | EzIP ID | EzIP | Extended | Extended | 673 6 | (Source) | Option Length | Source | Source | 674 | (0X9A) | (6) | No.-1 | No.-2 | 675 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 676 | Extended | Extended | EzIP ID | EzIP | 677 7 | Source | Source | (Destination) | Option Length | 678 | No.-3 | No.-4 | (0X9A) | (6) | 679 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 680 | Extended | Extended | Extended | Extended | 681 8 | Destination | Destination | Destination | Destination | 682 | No.-1 | No.-2 | No.-3 | No.-4 | 683 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 685 Figure 14 Full EzIP Header (Four octet) 687 2.7.2. In brief, Figure 12 or Figure 13 with seven words (40% 688 overhead) having two octet capacity is suitable to transport EzIP-1 689 through EzIP-4 types consisting of one or two octet Extension No. 690 EzIP-5 and EzIP-6 require the next IP header size which is eight 691 words (60% overhead) as shown in Figure 14. 693 2.7.3. Being a superset, utilizing "No Operation" or "End of Option 694 List" type of fillers, Figure 14 is capable of handling information 695 for EzIP-1 through EzIP-4 just as well. The question then becomes; 696 whether the extra 20% overhead when handling EzIP-1 through EzIP-4 697 headers is tolerable? If so, the single Figure 14 format may be used 698 for all EzIP cases. 700 2.7.4. With the "Network No." prefixes of the well-know private 701 network addresses all explicitly carried by the IP header of every 702 packet as shown in Figure 14, the Option Number only needs to 703 identify the length of the "Extended No.". Consequently, one Option 704 Number is sufficient to represent EzIP-1 through EzIP-3 that only the 705 first available octet is used for the Extension No. Similarly, one 706 single Option Number representing EzIP-4 through EzIP-6 conveys the 707 condition that all available bits are to be used for Extension No. 709 2.7.5. One potential drawback of the full four octet EzIP header is 710 that it may cause Internet routers to intercept a packet for 711 containing a disallowed (private network) IP address, although 712 positioned at a location of the header normally not designated for 713 address information. 715 2.7.6. By harmonizing EzIP-4 to -6 (EnIP) with EzIP-1 to -3 (ExIP) 716 into one common (EzIP) format, enjoying which operating 717 characteristics will simply be the result of a user subscribing to an 718 EzIP address type appropriate for how he wishes to use his IoT. 720 3. EzIP Deployment Strategy 722 Although the eventual goal of the SPR is to support both web server 723 access by IoTs from behind private networks and direct end-to-end 724 connectivity between IoTs, the former application should be addressed 725 first to immediately relieve the basic address shortage issue. Once 726 the IoTs on both ends of an intended connection are served by SPRs, 727 it will be natural to realize the latter. 729 A. Architecturally 731 Since the design philosophy of the SPR is an inline module between 732 the Internet ER (Edge Router) and the private network RG (Routing 733 Gateway), SPR introduction process may be flexible. 735 A.1. SPRs may be collocated with ERs to begin providing the CGNAT 736 equivalent function. This may be done immediately without affecting 737 the existing Internet (edge and core) routers. EzIP-capable IoTs 738 will then take advantage of the faster bi-directional routing 739 services through the SPRs by initiating a communication session with 740 an EzIP header. 742 A.2. Alternatively, a SPR may be deployed as an adjunct module 743 before an existing RG to realize the same EzIP functions on private 744 premises, even if the serving Internet Service Provider (ISP) has not 745 enhanced ERs with the EzIP capability. This empowers individual 746 subscribers to enjoy the new EzIP capability on their own. 748 B. Functionally 750 B.1. First, an ISP should install SPRs in front of business web 751 servers so that new routing branches may be added to support the 752 additional web servers for expanding business activities. 753 Alternatively, this may be achieved by deploying new web servers with 754 the SPR function built-in. 756 B.2. On the subscriber side, SPRs should be deployed to relieve 757 the public address shortage issue, and to facilitate the access to 758 new web servers. 760 C. Permanently 762 In the long run, it would be best if SPRs are integrated into ERs by 763 upgrading the latter's firmware to minimize the hardware. 765 Appendix C details the considerations in implementing these outlines. 767 4. Updating Servers to Support EzIP 769 Although the IP header Option mechanism utilized by EzIP was defined 770 a long time ago as part of the original IPv4 protocol, it has not 771 been used much in daily traffic. Certain current Internet facilities 772 were thus optimized without considering the Option mechanism. They 773 need be adjusted to provide the same performance to EzIP packets. 774 There are also utility type of servers need be updated to support the 775 longer EzIP address. For example; 777 A. Fast Path 779 Internet Core Routers (CRs) are currently optimized to only provide 780 the "fast-path" (through hardware line card) routing service to 781 packets without Option word in the IP header [11]. This puts EzIP 782 packets in a disadvantage, because EzIP packets would be put through 783 the "slow path" (processed by CPU's software before giving to the 784 correct hardware line card to forward), resulting in a slower 785 throughput. Since the immediate goal of the EzIP is to ease the 786 address pool exhaustion issue, subscribers not demanding for high 787 performance traffic may be assigned with the facility provided 788 through EzIP. This gives time for Internet routers to update so that 789 EzIP packets with authorized Option numbers will eventually be 790 recognized for receiving the "fast-path" service. 792 B. Connectivity Verification 794 One frequently used utility for verifying baseline connectivity, 795 commonly referred to as the "PING" function in PC terminology, needs 796 be able to transport the full EzIP address that is longer than the 797 standard 32 bit IPv4 address. There is an example of an upgraded TCP 798 echo server in [RFC862] [12]. 800 C. Domain Name Server (DNS) 802 Similarly, the DNS needs to expand its data format to transport the 803 longer IP address created by EzIP. This already can be done under 804 IPv6. Utilizing the experimental IPv6 prefix 2001:0101 defined by 805 [RFC2928] [13], EzIP addresses may be transported as standardized 806 AAAA records. 808 These topics are discussed in more detail under the IETF Draft RFC, 809 Enhanced IPv4 - V.03 [5]. 811 5. EzIP Enhancements 813 To minimize disturbing any assigned addresses, deployed equipment and 814 current operation procedures, etc., the EzIP derivations so far are 815 conducted under the constraint of utilizing only the existing three 816 reserved private network address blocks. Beyond such, there are other 817 possibilities. In the long run, EzIP may significantly expand the 818 current IPv4 public address pool through the employment of such 819 additional resources outlined below. 821 A. In reviewing the IP Option Number assignments [10], it is 822 discovered that more than a dozen of them are currently available. 823 That is, besides five numbers, 26, 27, 28, 29 & 31 that have never 824 been assigned, there are eleven numbers assigned earlier but have 825 been deprecated due to the end of associated experiments. If we take 826 six such numbers, one to represent each of the six EzIP extension 827 types, the EzIP-1 to EzIP-3 cases will multiply the IPv4 public 828 address pool by a factor of 256, individually, or a combined factor 829 of 768, resulting in 3,145.728B, or 3.146KB publicly assignable 830 addresses. Similarly, we can use one Option Number for each of the 831 EzIP-4, -5 and -6 cases to multiply IPv4 pool by 64K, 1M and 16M (a 832 total of 17.1M) fold, respectively, to the combined total of 69.894MB 833 addresses. These capacities are over 63 and 1.4M times of the 834 expected Year 2020 IoTs, respectively. 836 B. EzIP-8: If all Option numbers were made available, each 837 representing one EzIP Network No. prefix, up to 32 private network 838 address blocks, like the 10/8 could be utilized by EzIP. To determine 839 the upper limit of this scenario, let's assume that we could employ 840 31 additional 10/8 type address blocks, say by re-designating 11/8 841 through 41/8 as private network blocks. These enable us to expand 842 each existing IPv4 public address by 32 x 16M or 512M fold. Since 843 this block of 512M addresses have to be removed from the basic public 844 pool, the resulting total addresses will be (4.096B - 512M) x 512M, 845 or 1,835MB. This is over 35M times of the predicted number of IoTs 846 (50B) by Year 2020. It certainly has the capacity to deal with the 847 short- to mid- term public IP address needs. 849 C. The above may be condensed for a more efficient operation. For 850 example, a single 224/3 block contains the same amount of 512M 851 addresses may be chosen upon re-allocation of currently assigned IPv4 852 public addresses so that just one Option Number may represent it. Now 853 that we have freed up 31 Option numbers, we could allocate up to 31 854 more /3 address blocks for EzIP operation that provides even more 855 extension address resource. However, this last step will exceed the 856 total capacity of the IPv4 pool. On the other hand, this line of 857 reasoning leads to the next observation. 859 D. EzIP-9: One interesting consequence of the EzIP header in Figure 860 144 capable of transporting the full 32 bit private network address 861 is that the Extension No. may be as long as practical. That is, we 862 can go to the extreme of reserving only one bit for the Network No., 863 and leaving nothing for the IoT No. With these criteria, the current 864 IPv4 pool may be divided into two halves, reserving one half of it 865 (about 2B addresses) as a private network with prefix equal to "1" as 866 the Network No., and all trailing 31 bits designated as Extension No. 867 Each of the remaining 2B addresses (with prefix equals to "0") of the 868 basic IPv4 pool may then be expanded 2B times through the EzIP 869 process, resulting in a total of 4BB addresses that are IPv4 870 compatible and capable of full end-to-end connectivity. This is 871 roughly 80M times of the Year 2020 IoTs. 873 E. EzIP-7: On the other hand, this full 32 bit EzIP addresses 874 transport facility may be applied to the elusive IPv4 240/4 block 875 (240/8 - 255/8) consisting of 256M addresses that has become 876 "RESERVED for Future use" [14] as the result of the historical 877 address assignment evolution. Since this block is not suitable for 878 being used as public address, it might as well be re-classified as an 879 additional (the fourth) reusable private network pool. Then, the SPR 880 may use this block as the extension address pool in the EzIP process. 881 Following this approach, each current IPv4 public address may be 882 multiplied by 256M times based on only one Option Number. Since the 883 240/4 block could not be used for public addressing, the size of the 884 publicly assignable IPv4 pool has actually been only 3.84B (4.096B - 885 256M). So, the net public addressable pool created from this approach 886 is 983MB (3.84B x 256M), which is over 19.6M times of the expected 887 Year 2020 IoTs. This scheme is very close to EzIP-8. Although half of 888 the capacity, this manifestation has the advantage of circumventing 889 reassignment of public IPv4 addresses. 891 The following compares various IPv4 public address pool expansion 892 configurations. 894 | Extension |Option|Effect. |Expansion|Assignable| SUP/|Connect- | 895 | Scheme | Used | AddBits| Factor | Pub Add | DMD | ivity | 896 +=============+======+========+=========+==========+=====+=========+ 897 | IPv4 Public Address Block Assignments Unchanged | 898 +---+---------+------+--------+---------+----------+-----+---------+ 899 | E | EzIP-1 | 1 | 40 | 256 | 978.69B | 19.6| PrivNet | 900 | x +---------+------+--------+---------+----------+-----+---------+ 901 | I | EzIP-2 | 1 | 40 | 256 | 978.69B | 19.6| PrivNet | 902 | P +---------+------+--------+---------+----------+-----+---------+ 903 | | EzIP-3 | 1 | 40 | 256 | 978.69B | 19.6| PrivNet | 904 +---+---------+------+--------+---------+----------+-----+---------+ 905 | E | EzIP-4 | 1 | 48 | 64K | 244.67KB | 5K |EndToEnd | 906 | n +---------+------+--------+---------+----------+-----+---------+ 907 | I | EzIP-5 | 1 | 52 | 1M | 3.82MB | 77K |EndToEnd | 908 | P +---------+------+--------+---------+----------+-----+---------+ 909 | | EzIP-6 | 1 | 56 | 16M | 61.17MB | 1M |EndToEnd | 910 +---+---------+------+--------+---------+----------+-----+---------+ 911 |EzIP-7(240/4)| 1 | 60 | 256M | 978.69MB | 20M |EndToEnd | 912 +=============+======+========+=========+==========+=====+=========+ 913 | IPv4 Public Address Block Assignments Adjusted | 914 +-------------+------+--------+---------+----------+-----+---------+ 915 | EzIP-8 | | | | | | | 916 | (224/3) | 1 | 61 | 512M | 1.84BB | 37M |EndToEnd | 917 +-------------+------+--------+---------+----------+-----+---------+ 918 | EzIP-9 | | | | | | | 919 | (Half of | 1 | 63 | 2B | 4BB | 80M |EndToEnd | 920 | IPv4 Pool) | | | | | | | 921 +=============+======+========+=========+==========+=====+=========+ 923 Notes: 925 a. EzIP-1 through EzIP-7 Assignable Public Addresses calculated with 926 the net basic IPv4 public address pool of 3.823B after removed the 927 240/4, 10/8, 172.16/12 and 192.168/16 blocks from the basic 4.096B 929 b. EzIP-8 and EzIP-9 Assignable Public Addresses calculation started 930 from scratch based on the full IPv4 pool of 4.096B minus only the 931 specific portion used for extension purpose 933 c. "SUP/DMD": Ratio of EzIP SUPplied publicly assignable addresses to 934 IoT DeManD by Year 2020 936 d. Each group of EzIP-1 to -3 and EzIP-4 to -6 may use only one 937 Option number if "four octet" EzIP headers are used. 939 Figure 15 IPv4 Address Multiplication Possibilities 941 F. It is important to note that schemes summarized in Figure 15 are 942 not mutually exclusive but mostly complementary. Except the last two 943 cases (EzIP-8 and EzIP-9) that are intend to demonstrate the 944 potential public address sizes by starting from the full 4.096B IPv4 945 pool ignoring the current assignments and reservations, EzIP-1 946 through EzIP-7 may be applied to the same public IPv4 address since 947 they are distinguished from one another by the Option Numbers 948 representing the network prefix and the number of Extension No. bits. 949 These enable an ISP to offer a rich mixture of addresses for the 950 subscribers to choose from. 952 G. An address extended by EzIP-4 through EzIP-7 directly connecting 953 an IoT to the Internet could nevertheless be replaced by a private 954 network established through an RG as described at the end of Appendix 955 B. The EzIP-7 can best take advantage of this approach, because the 956 240/4 address block is totally segregated from the three conventional 957 private network pools, thus avoiding confusing the Internet routers. 958 Essentially, the subscribers, appearing as private networks and 959 directly connected IoTs, will interface with a complete spherical 960 layer of secondary ERs (made of the SPRs) that wraps the entire 961 existing Internet within by utilizing a never assigned address pool. 963 H. In summary, the EzIP technique may expand the current IPv4 public 964 address pool with a wide range of multiplication factors. It may be 965 256 folds while maintaining the current private network properties 966 except with reduced size, and from 64K to 256M folds while offering 967 direct end-to-end connectivity. In addition, multiplication factor of 968 512M may be achieved with some re-assignments of the IPv4 blocks. 969 Lastly, the address capacity could even become 1B times of the 970 current 4B pool with fully direct end-to-end connectivity. However, 971 these last two EzIP manifestations rely on significant realignments 972 of the current address blocks. In between, we could have an IPv4 973 based Internet that can simultaneously support private networks along 974 with directly accessible IoTs for interconnectivity and 975 interoperability. 977 I. Overall, EzIP-7 may be the optimum choice. It utilizes a block of 978 IPv4 addresses that could not be assigned as public identifiers 979 anyway. It needs only one Option Number. Furthermore, existing 980 private network setups may remain intact. Essentially, EzIP-7 981 introduces a new layer of routers (made of the SPRs) that expands the 982 Internet address capacity by 256M fold uniformly, with minimum 983 disturbance to the current Internet operations. 985 6. Security Considerations 987 The EzIP solution is based on an inline module called SPR that 988 intends to be as transparent to the Internet traffic as possible. 989 Thus, no overall system security degradation is expected. 991 7. IANA Considerations 993 This draft does not create a new registry nor does it register any 994 values in existing registries; no IANA action is required. 996 8. Conclusions 998 This draft RFC describes an enhancement to IPv4 operation utilizing 999 IP header Option mechanism. Because the design criterion is to 1000 enhance IPv4 by extending instead of altering it, the impact on 1001 already in-place routers and security mechanisms is minimized. 1003 To resolve the IPv4 public address pool exhaustion issue, a technique 1004 called EzIP (phonetic for Easy IPv4) making use of the reserved 1005 private network address blocks is proposed. 1007 The basic EzIP intention is to maintain the existing private network 1008 configuration. If an Extension No. for EzIP is chosen from the very 1009 end of the 32 bit reserved private network address, leading to no 1010 address bit available to assign on the resultant network, the IoT 1011 being served is directly accessible from any remote device in the 1012 Internet. An IoT may communicate through the Internet with either 1013 type of the connectivity, depending on which type of extension 1014 address its owner wishes to subscribe and to utilize with. 1016 The basic EzIP header uses two added words (or 40% overhead) to the 1017 IP header for transporting two octets of an Extension No. To carry 1018 the full four octet EzIP extension address, a third added word is 1019 needed resulting in a 60% overhead. The latter, being a superset of 1020 the former, may be used for all EzIP cases if the extra 20% overhead 1021 is tolerable for cases when the larger capacity is not necessary. 1023 At the extreme end of the spectrum, the EzIP scheme could be 1024 configured to support an IPv4 compatible pool of up to 4BB addresses 1025 with full direct end-to-end connectivity. 1027 Last but not the least, the "RESERVED for Future use" 240/4 block may 1028 be re-classified as the fourth reusable private network pool, so that 1029 the SPR may use it as the EzIP extension address. This pool can 1030 multiply each current IPv4 public address by 256M times based on only 1031 one Option Number, while all existing subscriber premises setups 1032 (private networks and directly connected IoTs) may remain unchanged. 1033 This manifestation of EzIP technique may be the optimal solution to 1034 our needs. 1036 9. References 1038 9.1. Normative References 1040 (None) 1042 9.2. Informative References 1044 [1] https://nishithsblog.files.wordpress.com/2014/04/internet-of- 1045 things-market-forecast.jpg 1047 [2] http://stats.labs.apnic.net/ipv6 1049 [3] https://ams-ix.net/technical/statistics/sflow-stats/ether-type 1051 [4] http://www.avinta.com/phoenix-1/home/IETF-Draft-ExIP.pdf 1053 [5] https://tools.ietf.org/html/draft-chimiak-enhanced-ipv4-03 1055 [6] https://tools.ietf.org/html/rfc793 1057 [7] https://www.ietf.org/rfc/rfc2131.txt 1059 [8] https://tools.ietf.org/html/rfc791 1061 [9] https://tools.ietf.org/html/rfc1385 1063 [10] http://www.iana.org/assignments/ip-parameters/ip- 1064 parameters.xhtml 1066 [11] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.477.19 1067 42&rep=rep1&type=pdf 1069 [12] https://tools.ietf.org/html/rfc862 1071 [13] https://tools.ietf.org/html/rfc2928 1073 [14] http://www.iana.org/assignments/ipv4-address-space/ipv4- 1074 address-space.xhtml 1076 10. Acknowledgments 1078 The authors would express their deep appreciation to Dr. W. Chimiak 1079 for the enlightening discussions about his team's efforts and 1080 experiences through the EnIP development. 1082 This document was prepared using 2-Word-v2.0.template.dot. 1084 Appendix A EzIP System Architecture 1086 A.1. EzIP System Part A 1088 The EzIP-1 and EzIP-4 portions of the EzIP system has already been 1089 shown as Figure 9 in the main body of this Draft document. 1091 A.2. EzIP System Part B 1093 The EzIP-2 portion maintains private network operation 1094 characteristics, while EzIP-5 portion delivers end-to-end 1095 connectivity. 1097 +------+ 1098 Web Server | WS0z | 1099 +--+---+ 1100 |69.41.190.145 1101 | 1102 | +-----+ 1103 +--+ ER0 | 1104 +--+--+ 1105 | 1106 +------+-------+ 1107 +-------+ Internet +--------+ 1108 | |(Core Routers)| | 1109 +--+--+ +--------------+ +--+--+ 1110 +-----+ ER2 | +-----+ ER5 | 1111 | +-----+ | +-----+ 1112 EzIP-2 |69.41.190.120 EzIP-5 |69.41.190.158 1113 +--+--+ +--+--+ 1114 +-----------+ +-------+ +---------+ +------+ 1115 | +-----+ SPR2| | | +-----+ SPR5+--+ | 1116 | | +-----+ | | | +-----+ | | 1117 | | ................. | |...| |...| 1118 172.16.1.0 |172.16.2.0 172.31.240.0 | | +---------+ | 1119 +--+--+ | | | | 1120 +---+ RG2 +--+ 172.16.1.0 | | 172.31.255.255 1121 | +-----+ | | | 1122 | Premises 2 | +----------+ | 1123 | | | Premises 5 | 1124 |172.16.2.3 |172.16.2.9 |172.16.5.10 |172.16.5.40 1125 +--+--+ +--+--+ +--+--+ +--+--+ 1126 | T2a | .... | T2z | | T5a | ....... | T5z | 1127 +-----+ +-----+ +-----+ +-----+ 1129 Figure 16 EzIP System Architecture-B (172.16/12 Portion) 1131 A.3. EzIP System Part C 1133 The EzIP-3 portion maintains private network operation 1134 characteristics, while EzIP-6 portion delivers end-to-end 1135 connectivity. 1137 +------+ 1138 Web Server | WS0z | 1139 +--+---+ 1140 |69.41.190.145 1141 | 1142 | +-----+ 1143 +--+ ER0 | 1144 +--+--+ 1145 | 1146 +------+-------+ 1147 +-------+ Internet +--------+ 1148 | |(Core Routers)| | 1149 +--+--+ +--------------+ +--+--+ 1150 +-----+ ER3 | +-----+ ER6 | 1151 | +-----+ | +-----+ 1152 | | 1153 EzIP-3 |69.41.190.130 EzIP-6 |69.41.190.160 1154 +--+--+ +--+--+ 1155 +-----------+ +-------+ +---------+ +------+ 1156 | +-----+ SPR3| | | +-----+ SPR6+--+ | 1157 | | +-----+ | | | +-----+ | | 1158 | ... | ................. | | | | | 1159 | | | |...| |...| 1160 10.1.0.0 |10.3.0.0 10.255.0.0 | | +---------+ | 1161 +--+--+ | | | | 1162 +---+ RG3 +--+ 10.1.0.0 | | 10.255.255.255 1163 | +-----+ | | | 1164 | Premises 3 | +----------+ | 1165 | | | Premises 6 | 1166 |10.3.0.3 |10.3.255.9 |10.6.0.10 |10.6.0.40 1167 +--+--+ +--+--+ +--+--+ +--+--+ 1168 | T3a | .... | T3z | | T6a | ....... | T6z | 1169 +-----+ +-----+ +-----+ +-----+ 1171 Figure 17 EzIP System Architecture-C (10/8 Portion) 1173 A.4. EzIP System Part D 1175 Utilizing 240/4, the EzIP provides a "spherical shell" of routable 1176 addresses wrapped around the entire current Internet (CRs and ERs), 1177 separating it from the subscribers' IoTs that are either directly 1178 addressable from the Internet such as T7z, T8z, or behind existing 1179 private networks like RG7, RG8. 1181 +------+ 1182 Web Server | WS0z | 1183 +--+---+ 1184 |69.41.190.145 1185 | 1186 | +-----+ 1187 +--+ ER0 | 1188 +--+--+ 1189 | 1190 +------+-------+ 1191 ER1 ------+ +----- ER4 1192 Interconnect | | 1193 with ER2 ------+ Internet +----- ER5 1194 Preceding | | 1195 Figures ER3 ------+(Core Routers)+----- ER6 1196 | | 1197 +-------+ +--------+ 1198 | | | | 1199 +--+--+ +--------------+ +--+--+ 1200 +-----+ ER7 | +-----+ ER8 | 1201 | +-----+ | +-----+ 1202 | | 1203 |69.41.190.170 |69.41.190.180 1204 +--+--+ +--+--+ 1205 +-----------+ +-------+ +---------+ +------+ 1206 | +-----+ SPR7+--+ |EzIP-7 | +-----+ SPR8+--+ | 1207 | ... | +-----+ |... | | | +-----+ | | 1208 | | +--------+ | |...| |...| 1209 240.0.0.1 | | 255.255.255.255 | | +---------+ | 1210 | | | | | | 1211 +------+ | 240.0.0.1 | | 255.255.255.255 1212 | Premises 7 | +----------+ | 1213 | | | Premises 8 | 1214 |247.0.0.3 |247.0.0.9 |248.0.0.10 |248.0.0.40 1215 +--+--+ +--+--+ +--+--+ +--+--+ 1216 | RG7 | .... | T7z | | T8z | ....... | RG8 | 1217 +-----+ +-----+ +-----+ +-----+ 1219 Figure 18 EzIP System Architecture-D (240/4 Portion) 1221 +--------------------------+-----------------+----------------+ 1222 | | Basic IPv4 | EzIP-capable | 1223 +--------------------------+-----------------+----------------+ 1224 | | ER0, ER1, ER2, | ------------ | 1225 | Internet Edge Router (ER)| ER3, ER4, ER5, | | 1226 | | ER6, ER7, ER8 | | 1227 +--------------------------+-----------------+----------------+ 1228 | | T1a, T2a, T3a, | T1z, T2z, T3z, | 1229 | Internet of Things (IoT) | T4a, T5a, T6a, | T4z, T5z, T6z, | 1230 | | | T7z, T8z | 1231 +--------------------------+-----------------+----------------+ 1232 | | RG1, RG2, RG3 | | 1233 | Routing Gateway (RG) | RG7, RG8 | ------------ | 1234 +--------------------------+-----------------+----------------+ 1235 | | ------------- | SPR1, SPR2, | 1236 | Semi-Public Router (SPR) | | SPR3, SPR4, | 1237 | | | SPR5, SPR6, | 1238 | | | SPR7, SPR8 | 1239 +--------------------------+-----------------+----------------+ 1240 | Web Server (WS) | ------------- | WS0z | 1241 +--------------------------+-----------------+----------------+ 1243 Note: WS0z could be either a collection of conventional web servers 1244 connected to the Internet via a SPR, with message transfer capability 1245 among themselves, or a new web sever with multiple modules that 1246 recognize and re-direct packets depending on its header (conventional 1247 IP or EzIP) type. The main path functions the same as existing web 1248 servers. The secondary servers are on EzIP extension addresses that 1249 may be directly accessed by packets with EzIP header, or receive 1250 packets forwarded through the main module upon being qualified. 1252 Figure 19 EzIP System Components 1254 Appendix B EzIP Operation 1256 To demonstrate how EzIP could support and enhance the Internet 1257 operations, the following are three connection examples that involve 1258 SPRs as shown in Figure 9. These present a general perspective of how 1259 IP header transitions through the routers may look like. 1261 A. The first example is between EzIP-unaware IoTs, T1a and T4a. This 1262 operation is very much like the conventional TCP/IP packet 1263 transmission except with SPRs acting as an extra pair of routers 1264 supported by CGNAT. In addition, SPR4 may be viewed as a full-fledged 1265 RG minus DHCP and NAT support, because it assigns its IoTs with 1266 static addresses from the entire range of reserved 192.168/16, 1267 instead of the common much smaller pool of 192.168.nnn/24. 1269 B. The second one is between EzIP-capable IoTs, T1z and T4z. Here, 1270 the SPRs process the extended public IP addresses in router mode, 1271 avoiding the delays due to the NAT type of operations. 1273 C. The last one is between EzIP-unaware and EzIP-capable IoTs. By 1274 initiating and responding with a conventional IP header, T1z and T4z 1275 behave like an EzIP-unaware IoT. Thus, all packet exchanges use the 1276 conventional IP headers, just like case A. above. 1278 B.1. Connection between EzIP-unaware IoTs 1280 B.1.1. T1a Initiates a Session Request towards T4a 1282 In Figure 20, T1a initiates a session request to SPR4 that serves T4a 1283 by sending an IP packet to RG1. There is no TCP port number in this 1284 IP header yet. 1286 0 1 2 3 1287 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 1288 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1289 1 |Version|IHL (5)|Type of Service| Total Length (20) | 1290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1291 2 | Identification |Flags| Fragment Offset | 1292 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1293 3 | Time to Live | Protocol | Header Checksum | 1294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1295 4 | Source Host Number (192.168.1.3) | 1296 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1297 5 | Destination Host Number (69.41.190.148) | 1298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1300 Figure 20 IP Header: From T1a to RG1 1302 B.1.2. RG1 Forwards the Packet to SPR1 1304 In Figure 21, RG1, allowing be masqueraded by T1a, relays the 1305 packet toward SPR1 by assigning the TCP Source port number, 3N, to 1306 T1a. Note that the suffix "N" denotes the actual TCP port number 1307 assigned by the RG1's NAT. This could assume multiple values, each 1308 represents a separate communications session that T1a is engaged in. 1309 A corresponding entry is created in the state table for handling the 1310 responding packet from the Destination site. Since T4a's TCP port 1311 number is not known yet, it is filled with all 1's. 1313 0 1 2 3 1314 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 1315 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1316 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1317 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1318 2 | Identification |Flags| Fragment Offset | 1319 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1320 3 | Time to Live | Protocol | Header Checksum | 1321 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1322 4 | Source Host Number (192.168.1.0) | 1323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1324 5 | Destination Host Number (69.41.190.148) | 1325 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1326 6 | Source Port (3N) | Destination Port (All 1's) | 1327 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1329 Figure 21 TCP/IP Header: From RG1 to SPR1 1331 B.1.3. SPR1 Sends the Packet to SPR4 through the Internet 1333 In Figure 22, SPR1 allowing masqueraded by RG1 (with the Source Host 1334 Number changed to be its own and the TCP port number changed to 1C, 1335 where "C" stands for CGNAT) sends the packet out through the Internet 1336 towards SPR4. The packet traverses through the Internet (ER1, CR and 1337 ER4) utilizing only the basic IP header portion of address 1338 information (words 4 & 5). 1340 0 1 2 3 1341 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 1342 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1343 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1344 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1345 2 | Identification |Flags| Fragment Offset | 1346 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1347 3 | Time to Live | Protocol | Header Checksum | 1348 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1349 4 | Source Host Number (69.41.190.110) | 1350 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1351 5 | Destination Host Number (69.41.190.148) | 1352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1353 6 | Source Port (1C) | Destination Port (All 1's) | 1354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1356 Figure 22 TCP/IP Header: From SPR1 to SPR4 1358 B.1.4. SPR4 Sends the Packet to T4a 1360 Since the packet has a conventional IP header without Destination TCP 1361 port number, SPR4 would ordinarily drop it due to the CGNAT function. 1362 However, for this example, let's assume that there exists a state- 1363 table that was set up by a DMZ process for redirecting this packet to 1364 T4a with a CGNAT TCP port number 410C (the composite of the third and 1365 the fourth octets, "4.10" of T4a's Extension No.). In Figure 23, SPR4 1366 sends the packet to T4a by constructing the destination address 1367 accordingly. 1369 0 1 2 3 1370 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 1371 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1372 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1373 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1374 2 | Identification |Flags| Fragment Offset | 1375 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1376 3 | Time to Live | Protocol | Header Checksum | 1377 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1378 4 | Source Host Number (69.41.190.110) | 1379 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1380 5 | Destination Host Number (192.168.4.10) | 1381 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1382 6 | Source Port (1C) | Destination Port (410C) | 1383 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1385 Figure 23 TCP/IP Header: From SPR4 to T4a 1387 B.1.5. T4a Replies to SPR4 1389 In Figure 24, when T4a replies to SPR4, it interchanges the Source 1390 and Destination identifications to create an IP header for the reply 1391 packet. 1393 0 1 2 3 1394 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 1395 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1396 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1397 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1398 2 | Identification |Flags| Fragment Offset | 1399 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1400 3 | Time to Live | Protocol | Header Checksum | 1401 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1402 4 | Source Host Number (192.168.4.10) | 1403 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1404 5 | Destination Host Number (69.41.190.110) | 1405 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1406 6 | Source Port (410C) | Destination Port (1C) | 1407 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1409 Figure 24 TCP/IP Header: From T4a to SPR4 1411 B.1.6. SPR4 Sends the Packet to SPR1 through the Internet 1413 In Figure 25, SPR4 sends the packet toward SPR1 with the following 1414 header through the Internet (ER4, CR and ER1) who will simply relay 1415 the packet according to the information in word 5 (Destination Host 1416 Number): 1418 0 1 2 3 1419 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 1420 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1421 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1422 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1423 2 | Identification |Flags| Fragment Offset | 1424 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1425 3 | Time to Live | Protocol | Header Checksum | 1426 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1427 4 | Source Host Number (69.41.190.148) | 1428 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1429 5 | Destination Host Number (69.41.190.110) | 1430 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1431 6 | Source Port (410C) | Destination Port (1C) | 1432 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1434 Figure 25 TCP/IP Header: From SPR4 to SPR1 1436 B.1.7. SPR1 Sends the Packet to RG1 1438 In Figure 26, RG1 address is reconstructed by using the information 1439 in the CGNAT state-table stored in SPR1. 1441 0 1 2 3 1442 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 1443 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1444 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1445 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1446 2 | Identification |Flags| Fragment Offset | 1447 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1448 3 | Time to Live | Protocol | Header Checksum | 1449 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1450 4 | Source Host Number (69.41.190.148) | 1451 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1452 5 | Destination Host Number (192.168.1.0) | 1453 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1454 6 | Source Port (410C) | Destination Port (3N) | 1455 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1457 Figure 26 TCP/IP Header: From SPR1 to RG1 1459 B.1.8. RG1 Forwards the Packet to T1a 1461 In Figure 27, T1a address is reconstructed from that of RG1 and the 1462 state-table in the NAT based on Destination Port (3N). 1464 0 1 2 3 1465 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 1466 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1467 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1468 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1469 2 | Identification |Flags| Fragment Offset | 1470 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1471 3 | Time to Live | Protocol | Header Checksum | 1472 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1473 4 | Source Host Number (69.41.190.148) | 1474 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1475 5 | Destination Host Number (192.168.1.3) | 1476 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1477 6 | Source Port (410C) | Destination Port (3N) | 1478 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1480 Figure 27 TCP/IP Header: From RG1 to T1a 1482 B.1.9. T1a Sends a Follow-up Packet to RG1 1484 To carry on the communication, T1a in Figure 28 sends the follow-up 1485 packet to RG1 with a full TCP/IP header. 1487 0 1 2 3 1488 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 1489 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1490 1 |Version|IHL (6)|Type of Service| Total Length (24) | 1491 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1492 2 | Identification |Flags| Fragment Offset | 1493 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1494 3 | Time to Live | Protocol | Header Checksum | 1495 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1496 4 | Source Host Number (192.168.1.3) | 1497 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1498 5 | Destination Host Number (69.41.190.148) | 1499 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1500 6 | Source Port (3N) | Destination Port (410C) | 1501 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1503 Figure 28 TCP/IP Header: Follow-up Packets From T1a to RG1 1505 B.2. Connection Between EzIP-capable IoTs 1507 The following is an example of EzIP operation between T1z and T4z 1508 shown in Figure 9. Each knows its own full "Public - EzIP : Private" 1509 network addresses, "69.41.190.110-192.168.1.0:9" and "69.41.190.148- 1510 192.168.4.40", respectively, as well as the other's. Note that T4z 1511 full address does not have the IoT No. portion. It is directly 1512 addressable from the Internet. 1514 B.2.1. T1z Initiates a Session Request towards T4z 1516 T1z initiates a session request to T4z by sending an EzIP packet to 1517 RG1. There is no TCP port number word, because T4z does not have such 1518 and that for T1z has not been assigned by the RG1's NAT. 1520 0 1 2 3 1521 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 1522 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1523 1 |Version|IHL (7)|Type of Service| Total Length (28) | 1524 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1525 2 | Identification |Flags| Fragment Offset | 1526 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1527 3 | Time to Live | Protocol | Header Checksum | 1528 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1529 4 | Source Host Number (192.168.1.9) | 1530 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1531 5 | Destination Host Number (69.41.190.148) | 1532 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1533 | EzIP ID | EzIP | Extended | No | 1534 6 | (Source) | Option Length | Source | Operation | 1535 | (0X9B) | (3) | No. (1) | (00000001) | 1536 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1537 | EzIP ID | EzIP | Extended | Extended | 1538 7 | (Destination) | Option Length | Destination | Destination | 1539 | (0X9A) | (4) | No. (4) | No. (40) | 1540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1542 Figure 29 EzIP Header: From T1z to RG1 1544 Note that 0X9A and 0X9B are temporarily selected from the available 1545 "IP Option Numbers" [10]. They were employed by prior efforts to 1546 facilitate the presentation of, EnIP and ExIP, respectively. These 1547 convey the concepts of transporting the value of the "Network No." as 1548 well as the number of octets needed in the "Extension No.". That is, 1549 both Option Numbers represent 192.168/16 as the EzIP Network No. 1550 prefix, while individually conveys two or one octets used in the 1551 Extension No., respectively. 1553 B.2.2. RG1 Forwards the Packet to SPR1 1555 In Figure 30, RG1, allowing to be masqueraded by T1z, relays the 1556 packet toward SPR1 by assigning the TCP Source port number, 9N, to 1557 T1z. Since T4z is directly connected to the Internet, there is no 1558 private network information to fill the Destination portion of the 1559 TCP word. 1561 0 1 2 3 1562 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 1563 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1564 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1565 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1566 2 | Identification |Flags| Fragment Offset | 1567 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1568 3 | Time to Live | Protocol | Header Checksum | 1569 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1570 4 | Source Host Number (192.168.1.0) | 1571 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1572 5 | Destination Host Number (69.41.190.148) | 1573 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1574 | EzIP ID | EzIP | Extended | No | 1575 6 | (Source) | Option Length | Source | Operation | 1576 | (0X9B) | (3) | No. (1) | (00000001) | 1577 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1578 | EzIP ID | EzIP | Extended | Extended | 1579 7 | (Destination) | Option Length | Destination | Destination | 1580 | (0X9A) | (4) | No. (4) | No. (40) | 1581 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1582 8 | Source Port (9N) | Destination Port (All 1's) | 1583 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1585 Figure 30 TCP/EzIP Header: From RG1 to SPR1 1587 B.2.3. SPR1 Sends the Packet to SPR4 through the Internet 1589 In Figure 31, SPR1 sends the packet out into the Internet towards 1590 SPR4. The packet traverses through the Internet (ER1, CR and ER4), 1591 utilizing only the basic IP header portion of address information. 1592 Note that the third octet of word 6 plus the first two octets of word 1593 8 make up the subnet address of T1z. And, the last two octets of word 1594 7 represent the extended address of T4z. 1596 0 1 2 3 1597 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 1598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1599 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1600 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1601 2 | Identification |Flags| Fragment Offset | 1602 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1603 3 | Time to Live | Protocol | Header Checksum | 1604 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1605 4 | Source Host Number (69.41.190.110) | 1606 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1607 5 | Destination Host Number (69.41.190.148) | 1608 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1609 | EzIP ID | EzIP | Extended | No | 1610 6 | (Source) | Option Length | Source | Operation | 1611 | (0X9B) | (3) | No. (1) | (00000001) | 1612 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1613 | EzIP ID | EzIP | Extended | Extended | 1614 7 | (Destination) | Option Length | Destination | Destination | 1615 | (0X9A) | (4) | No. (4) | No. (40) | 1616 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1617 8 | Source Port (9N) | Destination Port (All 1's) | 1618 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1620 Figure 31 TCP/EzIP Header: From SPR1 to SPR4 1622 B.2.4. SPR4 Sends the Packet towards T4z to RG2 1624 In Figure 32, SPR4 sends the packet to RG2 by reconstructing its 1625 address from the Option number and the Extended Destination No. 1627 0 1 2 3 1628 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 1629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1630 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 2 | Identification |Flags| Fragment Offset | 1633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1634 3 | Time to Live | Protocol | Header Checksum | 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1636 4 | Source Host Number (69.41.190.110) | 1637 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1638 5 | Destination Host Number (192.168.4.40) | 1639 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1640 | EzIP ID | EzIP | Extended | No | 1641 6 | (Source) | Option Length | Source | Operation | 1642 | (0X9B) | (3) | No. (1) | (00000001) | 1643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1644 | EzIP ID | EzIP | Extended | Extended | 1645 7 | (Destination) | Option Length | Destination | Destination | 1646 | (0X9A) | (4) | No. (4) | No. (40) | 1647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1648 8 | Source Port (9N) | Destination Port (All 1's) | 1649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1651 Figure 32 TCP/EzIP Header: From SPR4 to T4z 1653 B.2.5. T4z Replies to SPR4 1655 In Figure 33, T4z replies to SPR4 with the full T1z identification 1656 (69.41.190.110-192.68.1.0:192.168.1.9N conveyed by Option ID 0X9B 1657 together with the compact address string 69.41.190.110-1:9N) to 1658 create an EzIP header for the reply packet. 1660 0 1 2 3 1661 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 1662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1665 2 | Identification |Flags| Fragment Offset | 1666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1667 3 | Time to Live | Protocol | Header Checksum | 1668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1669 4 | Source Host Number (192.168.4.40) | 1670 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1671 5 | Destination Host Number (69.41.190.110) | 1672 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1673 | EzIP ID | EzIP | Extended | Extended | 1674 6 | (Source) | Option Length | Source | Source | 1675 | (0X9A) | (4) | No. (4) | No. (40) | 1676 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1677 | EzIP ID | EzIP | Extended | End of | 1678 7 | (Destination) | Option Length | Destination | Option | 1679 | (0X9B) | (3) | No. (1) | (00000000) | 1680 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1681 8 | Source Port (All 1's) | Destination Port (9N) | 1682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1684 Figure 33 TCP/EzIP Header: From T4z to SPR4 1686 B.2.6. SPR4 Sends the Packet to SPR1 through the Internet 1688 In Figure 34, SPR4 sends the packet toward SPR1 with the following 1689 header through the Internet (ER2, CR, and ER1) who will simply relay 1690 the packet according to the information in word 5 (Destination Host 1691 Number): 1693 0 1 2 3 1694 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 1695 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1696 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1697 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1698 2 | Identification |Flags| Fragment Offset | 1699 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1700 3 | Time to Live | Protocol | Header Checksum | 1701 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1702 4 | Source Host Number (69.41.190.148) | 1703 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1704 5 | Destination Host Number (69.41.190.110) | 1705 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1706 | EzIP ID | EzIP | Extended | Extended | 1707 6 | (Source) | Option Length | Source | Source | 1708 | (0X9A) | (4) | No. (4) | No. (40) | 1709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1710 | EzIP ID | EzIP | Extended | End of | 1711 7 | (Destination) | Option Length | Destination | Option | 1712 | (0X9B) | (3) | No. (1) | (00000000) | 1713 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1714 8 | Source Port (All 1's) | Destination Port (9N) | 1715 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1717 Figure 34 TCP/EzIP Header: From SPR4 to SPR1 1719 B.2.7. SPR1 Sends the Packet to RG1 1721 In Figure 35, RG1 address is reconstructed from the Option number and 1722 the Extended Destination No. 1724 0 1 2 3 1725 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 1726 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1727 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1728 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1729 2 | Identification |Flags| Fragment Offset | 1730 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1731 3 | Time to Live | Protocol | Header Checksum | 1732 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1733 4 | Source Host Number (69.41.190.148) | 1734 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1735 5 | Destination Host Number (192.168.1.0) | 1736 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1737 | EzIP ID | EzIP | Extended | Extended | 1738 6 | (Source) | Option Length | Source | Source | 1739 | (0X9A) | (4) | No. (4) | No. (40) | 1740 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1741 | EzIP ID | EzIP | Extended | End of | 1742 7 | (Destination) | Option Length | Destination | Option | 1743 | (0X9B) | (3) | No. (1) | (00000000) | 1744 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1745 8 | Source Port (All 1's) | Destination Port (9N) | 1746 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1748 Figure 35 TCP/EzIP Header: From SPR1 to RG1 1750 B.2.8. RG1 Forwards the Packet to T1z 1752 In Figure 36, T1z address is reconstructed from that of RG1 and the 1753 NAT state-table based on Destination Port (9N). 1755 0 1 2 3 1756 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 1757 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1758 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1759 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1760 2 | Identification |Flags| Fragment Offset | 1761 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1762 3 | Time to Live | Protocol | Header Checksum | 1763 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1764 4 | Source Host Number (69.41.190.148) | 1765 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1766 5 | Destination Host Number (192.168.1.9) | 1767 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1768 | EzIP ID | EzIP | Extended | Extended | 1769 6 | (Source) | Option Length | Source | Source | 1770 | (0X9A) | (4) | No. (4) | No. (40) | 1771 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1772 | EzIP ID | EzIP | Extended | End of | 1773 7 | (Destination) | Option Length | Destination | Option | 1774 | (0X9B) | (3) | No. (1) | (00000000) | 1775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1776 8 | Source Port (All 1's) | Destination Port (9N) | 1777 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1779 Figure 36 TCP/EzIP Header: From RG1 to T1z 1781 B.2.9. T1z Sends a Follow-up Packet to RG1 1783 In Figure 37, T1z sends a follow-up packet to RG1 with all fields 1784 filled with needed information. 1786 0 1 2 3 1787 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 1788 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1789 1 |Version|IHL (7)|Type of Service| Total Length (32) | 1790 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1791 2 | Identification |Flags| Fragment Offset | 1792 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1793 3 | Time to Live | Protocol | Header Checksum | 1794 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1795 4 | Source Host Number (192.168.1.9) | 1796 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1797 5 | Destination Host Number (69.41.190.148) | 1798 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1799 | EzIP ID | EzIP | Extended | No Op | 1800 6 | (Source) | Option Length | Source | Option | 1801 | (0X9B) | (3) | No. (1) | (00000001) | 1802 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1803 | EzIP ID | EzIP | Extended | Extended | 1804 7 | (Destination) | Option Length | Destination | Destination | 1805 | (0X9A) | (4) | No. (4) | No. (40) | 1806 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1807 8 | Source Port (9N) | Destination Port (All 1's) | 1808 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1810 Figure 37 TCP/EzIP Header: Follow-up Packets from T1z to RG1 1812 B.3. Connection Between EzIP-unaware and EzIP-capable IoTs 1814 B.3.1. T1a initiates a request to T4z 1816 Since T1a can create only IP header with conventional format, the 1817 SPRs will provide CGNAT type of services to the IP packets. And, 1818 assuming SPR4 has a state-table set up by DMZ for forwarding the 1819 request to T4z, the packet will be delivered to T4z. Seeing the 1820 incoming packet using conventional IP header, T4z should respond with 1821 the same so that the session will be conducted with conventional 1822 TCP/IP headers. 1824 B.3.2. T1z initiates a request to T4a 1826 Knowing T4a is not capable of EzIP header, T1z purposely initiates 1827 the request packet using conventional IP header. It will be treated 1828 by SPRs in the same manner as the T1a initiated case above and 1829 recognizable by T4a. 1831 In brief, the steps outlined above are very much the same as the 1832 conventional TCP/IP header transitions between routers, except two 1833 extra steps in each direction are inserted to encode and decode the 1834 additional SPR provided EzIP routing process. 1836 Note that when an IoT, such as T4a or T4z, is directly connected to a 1837 SPR, like SPR4, there is no RG in-between. There is no corresponding 1838 TCP port number in word 8 of the above TCP/EzIP headers. This spare 1839 facility in the header allows an RG be inserted if desired, thus re- 1840 establishing the private network environment. 1842 When only its Extension No. portion of an EzIP extension address is 1843 transported in the EzIP header, the conventional private network 1844 address may be reused in this kind of added private networks. When 1845 extension address is transported by a full TCP/EzIP header with four 1846 octet format, proper precaution must be exercised to avoid confusing 1847 the routers along the way due to the appearance of a full private 1848 network address although at a location in the IP header not intended 1849 for ordinary IP address. When EzIP-7 is used, this is not of concern 1850 because the 240/4 block does not belong to the three conventional 1851 private network address blocks. 1853 Appendix C Internet Transition Considerations 1855 To enhance a large communication system like the Internet, it is 1856 important to minimize the disturbance to the existing equipments and 1857 processes due to any needed modification. The basic EzIP plan is to 1858 confine all actionable enhancements within the new SPR module. The 1859 following outlines the considerations for supporting the transition 1860 from the current Internet to the one enhanced by the EzIP technique. 1862 C.1. EzIP Implementation 1864 C.1.1. Introductory Phase: 1866 A. Insert an SPR in front of a web-server that desires to have 1867 additional subnet addresses for offering diversified activities. For 1868 the long term, a new web server may be designed with these two 1869 functional modules combined. 1871 . The first address of a private network address pool, e.g., 1872 192.168.0.0, used by the SPR should be reserved as a DMZ (De- 1873 Militarized Zone) channel directing the initial incoming service 1874 requesting packets to the existing web server. This will maintain the 1875 same operation behavior projected to the general public. 1877 . The additional addresses, up to 192.168.255.255 may be used for 1878 EzIP address extension purposes. Each may be assigned to an 1879 additional web server representing one of the business's new 1880 activities. Each of these new servers will then respond with EzIP 1881 header to messages forwarded from the main server, or be directly 1882 accessed through its EzIP address. 1884 B. Insert an SPR in front of a group of subscribers who are to be 1885 served with the EzIP function. The basic service provided by this SPR 1886 will be the CGNAT equivalent function. This will maintain the same 1887 baseline user experience in accessing the Internet. 1889 C. Session initiating packets with basic IPv4 header will be routed 1890 by SPRs to a business's existing server at the currently published 1891 IPv4 public address (discoverable by existing DNS). The server should 1892 respond with the basic IPv4 format as well. Essentially, this 1893 maintains the existing interaction between a user and a web server 1894 within an EzIP-unaware environment. 1896 So far, neither the web-server nor any subscriber's IoTs needs to 1897 be enhanced, because the operations remain pretty much the same as 1898 today's common practice utilizing CGNAT assisted connectivity. See 1899 Appendix B.1. for an example. 1901 D. Upon connected to the main web server, if a customer intentionally 1902 selects one of the new services offered by the primary web-server, 1903 the web-server will ask the customer to confirm the selection. 1905 . If confirmed, implying that the customer is aware of the fact 1906 that his IoT is being served by an SPR, the web server forwards the 1907 request to a branch server for carrying on the communication via an 1908 EzIP address. 1910 . The SPR at the originating side, recognizing the EzIP header 1911 from the web-server, replaces the CGNAT service with EzIP routing. 1913 . For all subsequent packets exchanged, the EzIP headers will be 1914 used in either direction. See Appendix B.2. for an example. This will 1915 speed up the transmission throughput performance for the rest of the 1916 session. 1918 C.1.2. New IoT Operation Modes: 1920 A. EzIP-capable IoT will create EzIP header in initiating a session, 1921 to directly reach a specific web-server, instead of the lengthy steps 1922 of going through the DMZ port followed by manually making the 1923 selection from the main web server. This will speed up the initial 1924 handshake process. See Appendix B.2. for an example. 1926 B. To communicate with an EzIP-unaware IoT, an EzIP-capable IoT 1927 should purposely initiate a session with conventional IP header. This 1928 will signal the SPRs to provide just CGNAT type of connection 1929 service. See Appendix B.3. for an example. 1931 C.1.3. End-to-End Operation: 1933 Once EzIP-capable IoTs become common for the general public, direct 1934 communication between any pair of such IoTs will be achievable. An 1935 EzIP-capable IoT, knowing the other IoT's full EzIP address, may 1936 initiate a session by creating an EzIP header that directs the SPRs 1937 to provide EzIP services, bypassing the CGNAT process. See Appendix 1938 B.2. for an example. 1940 C.2. SPR Operation Logic 1942 To support the above scenarios, the SPR should be designed with the 1943 following decision process: 1945 C.2.1. Initiating a Session Request for an IoT or via a RG 1946 If a session request IP packet contains EzIP Option word, it will be 1947 routed forward by SPR accordingly. Otherwise, the SPR provides CGNAT 1948 service by assigning a TCP port number to the packet and allowing the 1949 packet to masquerade with the SPR's own IP address while an entry to 1950 the state (port forward / look-up / hash) table is created in 1951 anticipation of the reply packet. 1953 C.2.2. Receiving a Session Request from the ER 1955 If a received IP packet includes a valid EzIP Option word or port 1956 number, SPR will utilize it to route the packet to an RG or an IoT. 1957 For a packet with plain IP header, it will be routed according to the 1958 Destination Host Number (IP header word 5). 1960 C.3. RG Enhancement 1962 With IPv4 address pool expanded by the EzIP schemes, there will be 1963 sufficient publicly assignable addresses for IoTs wishing to be 1964 directly accessible. The existing private networks may continue their 1965 current behavior of blocking session request packets from the 1966 Internet. In-between, another connection mode is possible. The 1967 following describes such an option in the context of the existing RG 1968 operation conventions. 1970 C.3.1. Initiating Session request for an IoT 1972 Without regard to whether the IP header is a conventional one or an 1973 EzIP type, a RG allows a packet to masquerade with the RG's own IP 1974 address by assigning a TCP port number to the packet and creating an 1975 entry to the state (port forward / look-up / hash) table. This is the 1976 same as current NAT practice. 1978 C.3.2. Receiving a packet from the SPR 1980 The "Destination Port" value in the packet is examined: 1982 A. If it matches with an entry in the RG NAT's state-table, the 1983 packet is forward to the corresponding address. This is the same as 1984 the normal NAT processes in a conventional RG. 1986 B. If it matches with the address of an active IoT on the private 1987 network, the packet is assigned with a TCP port number and then 1988 forwarded to that IoT. 1990 Note that there is certain amount of increased security risk with 1991 this added last step, because a match between a guessed destination 1992 identity and the above two lists could happen by chance. To address 1993 this issue, the following proactive mechanism may be incorporated in 1994 parallel: 1996 If the "Destination Port" number is null or does not match with 1997 either of the above cases, the packet is dropped and an alarm state 1998 is activated to monitor for possible ill-intended follow-up attempts. 1999 A defensive mechanism should be triggered when the number of failed 2000 attempts has exceeded the preset threshold within a finite time 2001 interval. 2003 In brief, if the IP header of a session requesting packet indicates 2004 that the sender knows the identity of the desired destination IoT on 2005 a private network, the common RG screening process will be bypassed. 2006 This facilitates the direct end-to-end connection, even in the 2007 presence of the NAT. Note that this process is very much the same as 2008 the AA (Automated Attendant) capability in a PABX telephone switching 2009 system that automatically makes the connection for a caller who 2010 indicates (via proper secondary dialing or the equivalent) knowing 2011 the extension number of the destination party. Such process can 2012 effectively screen out most of the unwanted callers. 2014 Authors' Addresses 2016 Abraham Y. Chen 2017 Avinta Communications, Inc. 2018 142 N. Milpitas Blvd., #148, Milpitas, CA 95035-4401 US 2020 Phone: _+1(408)942-1485 2021 Email: AYChen@Avinta.com 2023 Ramamurthy R. Ati 2024 Avinta Communications, Inc. 2025 142 N. Milpitas Blvd., #148, Milpitas, CA 95035-4401 US 2027 Phone: _+1(408)458-7109 2028 Email: rama_ati@outlook.com