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Versions: 00

<Network Working Group>                                      A. Y. Chen
Internet Draft                                                 R. R. Ati
Intended status: Experimental               Avinta Communications, Inc.
Expires: June 2017
                                                      December 13, 2016


                     IPv4 with Adaptive Address Space
                        draft-chen-ati-ezipd-00.txt


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   Abstract

   This document describes a solution to the Internet address depletion
   issue through the use of an existing Option mechanism that is part of
   the original IPv4 protocol. This proposal, named EzIP (phonetic for
   Easy IPv4), discusses the IPv4 public address pool expansion and the
   Internet system architecture enhancement aspects. It was originated
   by a study called ExIP (Extended IPv4) analyzing the use of the first
   available octet (eight bits) in the reserved private network pools
   (10/8, 172.16/12 and 192.168/16) to achieve a moderate address space
   expansion factor of 256 by each, while maintaining their familiar
   operation characteristics. Along the way, a parallel yet similar
   effort, called EnIP (Enhanced IPv4), was discovered. EnIP fully
   utilizes the same private network pools to increase the address space
   by a factor of 17.1M with end-to-end connectivity. EzIP is a superset
   that proposes one unified format for not only encompassing the
   considerations of both, but also identifying additional capabilities
   and flexibilities. For example, EzIP may expand an IPv4 address at
   least by a factor of 256 to as high as 256M without affecting the
   existing IPv4 public address assignments, while still keeping intact
   the current private networks for the 256M case if desired. The EzIP
   is in full conformance with the IPv4 protocol, and supports not only
   both categories of connectivity, but also their interoperability. The
   traditional Internet traffic and the IoT operations may coexist
   simultaneously without perturbing their existing setups, while
   offering end-users the freedom to choose one or the other. If the
   IPv4 public pool were reorganized, the assignable pool could be
   multiplied by 512M or even up to 2B times with end-to-end
   connectivity. EzIP may be deployed as a firmware enhancement to the
   Internet edge routers or private network gateways wherever needed, or
   simply installed as an inline adjunct module between the two,
   enabling a seamless introduction. The 256M case establishes a
   spherical layer of routers providing a complete interconnection
   between the Internet and end-users. This configuration enables the
   entire current Internet and private networks characteristics to
   remain intact. These proposed interim facilities would afford IPv6
   more time to orderly reach the maturity and the availability levels
   required for delivering a long-term general service.











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   Table of Contents


   1. Introduction...................................................4
      1.1. Contents of this Draft....................................5
   2. EzIP Overview..................................................6
      2.1. EzIP Numbering Plan.......................................6
      2.2. EzIP System Architecture.................................10
      2.3. IP Header with Option Word...............................13
      2.4. Examples of Option Mechanism.............................13
      2.5. Basic EzIP Header........................................14
      2.6. EzIP Operation...........................................16
      2.7. Generalizing EzIP Header.................................17
   3. EzIP Deployment Strategy......................................18
   4. Updating Servers to Support EzIP..............................19
   5. EzIP Enhancements.............................................20
   6. Security Considerations.......................................24
   7. IANA Considerations...........................................24
   8. Conclusions...................................................24
   9. References....................................................25
      9.1. Normative References.....................................25
      9.2. Informative References...................................25
   10. Acknowledgments..............................................26
   Appendix A  EzIP System Architecture.............................27
      A.1. EzIP System Part A.......................................27
      A.2. EzIP System Part B.......................................27
      A.3. EzIP System Part C.......................................28
      A.4. EzIP System Part D.......................................29
   Appendix B  EzIP Operation.......................................31
      B.1. Connection between EzIP-unaware IoTs.....................31
         B.1.1. T1a Initiates a Session Request towards T4a.........31
         B.1.2. RG1 Forwards the Packet to SPR1.....................32
         B.1.3. SPR1 Sends the Packet to SPR4 through the Internet..33
         B.1.4. SPR4 Sends the Packet to T4a........................34
         B.1.5. T4a Replies to SPR4.................................35
         B.2. Connection Between EzIP-capable IoTs..................39
         B.2.1. T1z Initiates a Session Request towards T4z.........39
         B.2.2. RG1 Forwards the Packet to SPR1.....................40
         B.2.3. SPR1 Sends the Packet to SPR4 through the Internet..41
         B.2.4. SPR4 Sends the Packet towards T4z to RG2............42
         B.2.5. T4z Replies to SPR4.................................43
         B.2.6. SPR4 Sends the Packet to SPR1 through the Internet..44
         B.2.7. SPR1 Sends the Packet to RG1........................45
         B.2.8. RG1 Forwards the Packet to T1z......................46
         B.2.9. T1z Sends a Follow-up Packet to RG1.................47
      B.3. Connection Between EzIP-unaware and EzIP-capable IoTs....47
         B.3.1. T1a initiates a request to T4z......................47


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         B.3.2. T1z initiates a request to T4a......................48
   Appendix C  Internet Transition Considerations...................49
      C.1. EzIP Implementation......................................49
      C.2. SPR Operation Logic......................................50
      C.3. RG Enhancement...........................................51


   1. Introduction

   For various reasons, there is a large demand for IP addresses. It
   would be useful to have a unique address for each Internet device,
   such that if desired, any device may call any other. The Internet of
   Things (IoT) would also be able to make use of more routable
   addresses if they were available. Currently, these are not possible
   with the existing IPv4 facility.

   By Year 2020, the population and number of IoTs are expected to reach
   7.6 billion and 50 billion respectively, according to a recent Cisco
   online paper [1].

   The IPv4 dot-decimal address format, consisting of four octets each
   made of 8 binary bits, results in the maximum number of assignable
   public addresses of 4.295 billion (calculated by 256 x 256 x 256 x
   256, to be 4,294,967,296 - decimal exact). Using the binary /
   shorthand notation of 64K representing 256 x 256 (decimal 65,536),
   the full IPv4 address pool of 64K x 64K may be expressed as 4,096M,
   or 4.096B. Clearly, the demand is more than 13 times over the
   inherent capability available from the supply.

   IPv6 with 128-bit hexadecimal address format offers a potential
   solution to this problem, but its global adoption appears to face
   certain challenges [2], [3]. Network Address and Port Translation
   (NAPT - commonly known simply as NAT) on private networks together
   with Carrier Grade NAT (CGNAT) over the Internet have been providing
   the interim solutions thus far. However, NAT modules slow down
   routers due to the state-table look-up process. As well, they only
   allow an Internet session be initiated by their respective own
   clients, impeding the end-to-end setup requests from remote devices
   that certain IoT operations desire.

   If the IPv4 capacity could be expanded to eliminate this address pool
   deficiency while maintaining the familiar established operation
   conventions, and perhaps even offers reasonable reserve, the urgency
   will be relaxed long enough for the IPv6 to mature on its own pace.

   To increase the Internet public address pool, there have been various
   proposals in the past. Among them, two recent efforts in particular


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   are referenced by this draft, namely ExIP and EnIP. The ExIP [4]
   study focuses on reclaiming part of a reserved private network
   address block, for example the third octet of 192.168/16, to be
   publicly routable at the edge of the Internet. By making use of this
   octet as semi-public address, the number of assignable public
   addresses is increased by a factor of 256 to become 1049B which is
   more than 20 times of the expected IoTs. This address expansion could
   be implemented in an inline module called Semi-Public Router (SPR)
   collocated with the Internet Edge Router (ER). Of course, the size of
   the resultant private networks will be reduced accordingly.

   The Enhanced IP (EnIP) [5] project proposes to increase the available
   IPv4 public address space by a factor of 17.1M. Like IPv6, EnIP
   results in full end-to-end connectivity among the enhanced addresses.
   The EnIP implementation module, "NAT and EnIPNAT/translator",
   replacing existing private network gateway, is very similar to the
   SPR.

   EzIP merges these two schemes into one uniform solution. Neither
   Internet Core (/ backbone) Router (CR), nor private network Routing
   Gateway (RG) needs to handle the Options added to the resultant IP
   header, since their designs recognize and preserve this Option
   mechanism, yet are not programmed to process the specific EzIP
   information. Even the Edge Routers (ER) may stay unchanged, if the
   SPR is deployed with the adjunct configuration during the
   introductory phase.

   The assignable IPv4 compatible public address pool may be expanded
   significantly more upon incorporating other available IPv4 resources
   by the EzIP technique, as discussed in the latter part of this
   document.

        1.1. Contents of this Draft

   The rest of this draft begins with outlining the EzIP numbering plan.
   A modified IP header called EzIP header is introduced for carrying
   the EzIP address data in the Option words. The overview of the
   Internet architecture as the result of being expanded by the EzIP
   scheme, the EzIP header transitions through various routers and the
   operation considerations are discussed next, with details presented
   in Appendices A, B and C, respectively. Utilizing the EzIP approach,
   a range of possibilities of expanding the publicly assignable IPv4
   address pool as well as enhancing the Internet operation flexibility
   are then described.





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   2. EzIP Overview

       2.1. EzIP Numbering Plan

   The ExIP technique which is the foundation of the EzIP plan began
   with making use of the reserved private network address pools in very
   much the same manner as Private Automatic Branch eXchange (PABX)
   telephone switching machines utilizing locally assigned "extension
   numbers" to expand the Public Switched Telephone Network (PSTN)
   capacity by replicating a public telephone line to multitudes of
   reusable private telephone numbers, each to identify a local
   instrument. At the first sight, this may seem odd, because the
   extension numbers of a PABX belong to a separate set from that of the
   public telephone numbers, while private network IP address is a
   specific subset reserved from the overall IPv4 pool that is otherwise
   all public. However, recognizing that neither of the latter two is
   allowed to operate in the other's domain suggests that the proposed
   EzIP numbering system indeed may mirror the telephony case. In fact,
   the very basic form of the EzIP numbering is to make explicit the
   familiar subnetting process of 192.168/16 that has been performed
   routinely by consumer RGs (Residential / Routing Gateways) on
   residential premises for a long time.

   2.1.1.   To facilitate the following discussions, the 32 bits in a
   private network address notation are divided into three parts, namely
   Network, Extension and IoT No.'s as shown in Figure 1 below.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     Network No.    -     Extension No.     :      IoT No.     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 1 EzIP Address Notation (Generic)

   The number of bits in the Extension No. part determines the
   multiplication factor to be applied by the EzIP process. The trailing
   IoT No. bits determine the size of the resultant private network. The
   Network No. part is the specific binary value of the remaining
   leading bits (the prefix) identifying an address block that will be
   reserved from the public IPv4 pool.

   2.1.2.   Following the general concept of subnetting, the unit for
   expanding an address does not need to be restricted to the boundary
   of an octet. This allows potentially finer grain resolution.




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   2.1.3.   How to utilize the 32 bits leads to tradeoffs among EzIP
   operation characteristics. For example, maintaining the private
   network properties or establishing the end-to-end connectivity is
   just a matter of whether there are bits reserved for the IoT No.

   2.1.4.   This notation may be used to present two general categories
   of EzIP address types:

      A. To retain the private network characteristics, the EzIP
   subnetting makes use of only the first available octet. For the
   common three private network address pools, we will have the
   following:

   In Figure 2, 8 bits are available for IoT No., resulting in private
   networks each capable of 256 IoTs.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            192.168            - Extension No. :    IoT No.    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Figure 2  EzIP-1 (8 bits of 192.168/16 semi-publicly addressable)

   In Figure 3, 12 bits are available for IoT No., resulting in private
   networks each capable of 4K IoTs.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           172.16      - Extension No. :        IoT No.        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Figure 3  EzIP-2 (8 bits of 172.16/12 semi-publicly addressable)















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   In Figure 4, 16 bits are available for IoT No., resulting in private
   networks each capable of 64K IoTs.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |       10      - Extension No. :            IoT No.            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

        Figure 4  EzIP-3 (8 bits of 10/8 semi-publicly addressable)



      B. To allow direct access from the Internet, EzIP makes use of all
   available bits in a reserved private network address as Extension
   No., leaving no bit for the IoT No. The resultant private network
   will have no RG, but only one IoT that is directly connected to the
   Internet:

   In Figure 5, 16 bits are assigned for Extension No., resulting in 64K
   IoTs directly addressable from the Internet.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            192.168            -          Extension No.        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Figure 5  EzIP-4 (16 bits of 192.168/16 semi-publicly addressable)

       In Figure 6, 20 bits are assigned for Extension No., resulting in
   1M IoTs directly addressable from the Internet.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            172.16     -             Extension No.             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Figure 6  EzIP-5 (20 bits of 172.16/12 semi-publicly addressable)









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   In Figure 7, 24 bits are assigned for Extension No., resulting in 16M
   IoTs directly addressable from the Internet.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |       10      -                 Extension No.                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 7  EzIP-6 (24 bits of 10/8 semi-publicly addressable)

   For cross reference purpose, EzIP-1 through EzIP-3 are the same
   numbering types used by the ExIP study, while EzIP-4 through EzIP-6
   are used by the EnIP project.

   Figure 8 summarizes the number of possible publicly and privately
   assignable addresses for each original IPv4 public address under
   different configurations.

                    |   192.168/16  |   172.16/12    |     10/8     |
      ==============+===============+================+==============+
        Basic IPv4  |               |                |              |
      --------------+---------------+----------------+--------------+
      Address Bits* |      32       |      32        |     32       |
      --------------+---------------+----------------+--------------+
         Public     |       1       |       1        |      1       |
         Private    |      64K      |       1M       |     16M      |
      ==============+===============+================+==============+
          (ExIP)    |    EzIP-1     |    EzIP-2      |    EzIP-3    |
      --------------+---------------+----------------+--------------+
      Address Bits* |      40       |      40        |     40       |
      --------------+---------------+----------------+--------------+
       Semi-Public  |     256       |     256        |    256       |
         Private    |     256       |       4K       |     64K      |
      ==============+===============+================+==============+
          (EnIP)    |    EzIP-4     |    EzIP-5      |    EzIP-6    |
      --------------+---------------+----------------+--------------+
      Address Bits* |      48       |      52        |     56       |
      --------------+---------------+----------------+--------------+
         Public     |      64K      |       1M       |     16M      |
         Private    |       1       |       1        |      1       |
      ==============+===============+================+==============+
   Notes:

   a. * -- Effective Overall Public Address Length




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   b. For each Public-Private pair, the numbers of addresses are
   multiplicative, not additive.

           Figure 8 Basic IPv4 Address Expansion Configurations

       2.2. EzIP System Architecture

   With six basic EzIP expansion types, it is difficult to include them
   all in one single system architecture diagram. A complete set of
   system architectural diagrams is presented in Appendix A. To
   facilitate the presentation, a partial system diagram covering only
   the 192.168/16 (EzIP-1 and EzIP-4) portion as presented in Figure 9
   below will be utilized for the discussions that follow.




































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                                       +------+
                        Web Server     | WS0z |
                                       +--+---+
                                          |69.41.190.145
                                          |
                                          |  +-----+
                                          +--+ ER0 |
                                             +--+--+
                                                |
                                         +------+-------+
                                 +-------+   Internet   +--------+
                                 |       |(Core Routers)|        |
                              +--+--+    +--------------+     +--+--+
                        +-----+ ER1 |                   +-----+ ER4 |
                        |     +-----+                   |     +-----+
                        |                               |
             EzIP-1     |69.41.190.110       EzIP-4     |69.41.190.148
                     +--+--+                         +--+--+
         +-----------+     +-------+       +---------+     +------+
         |     +-----+ SPR1|       |       |   +-----+ SPR4+--+   |
         |     |     +-----+       |       |   |     +-----+  |   |
         |   192.168.2.0 ... 192.168.255.0 |   |              |   |
         +-----+                           |...|              |...|
               |192.168.1.0                |   |    +---------+   |
            +--+--+                        |   |    |             |
        +---+ RG1 +--+            192.168.0.1  |    |  192.168.255.255
        |   +-----+  |                         |    |
        | Premises 1 |              +----------+    |
        |            |              |    Premises 4 |
        |192.168.1.3 |192.168.1.9   |192.168.4.10   |192.168.4.40
     +--+--+      +--+--+        +--+--+         +--+--+
     | T1a | .... | T1z |        | T4a | ....... | T4z |
     +-----+      +-----+        +-----+         +-----+


         Figure 9  EzIP System Architecture-A (192.168/16 Portion)













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   +--------------------------+-----------------+----------------+
   |                          |   Basic IPv4    |  EzIP-capable  |
   +--------------------------+-----------------+----------------+
   | Internet Edge Router (ER)|  ER0, ER1, ER4  |  ------------  |
   +--------------------------+-----------------+----------------+
   | Internet of Things (IoT) |    T1a, T4a     |    T1z, T4z    |
   +--------------------------+-----------------+----------------+
   | Routing Gateway (RG)     |       RG1       |  ------------  |
   +--------------------------+-----------------+----------------+
   | Semi-Public Router (SPR) |  -------------  |   SPR1, SPR4   |
   +--------------------------+-----------------+----------------+
   | Web Server (WS)          |  -------------  |      WS0z      |
   +--------------------------+-----------------+----------------+

                   Figure 10 EzIP-1 & EzIP-4 Components

   2.2.1.   Referring to the left portion labeled EzIP-1 of Figure 9,
   instead of assigning each premises a public IPv4 address as in the
   current practice, an SPR like SPR1, is inserted between an Internet
   Edge Router (ER1) and its connections to private network Routing
   Gateways like RG1, for utilizing the third octet, such as
   192.168.nnn/24 (nnn = 0 through 255) to identify respective entities.
   The RG1 serves either a LAN or a HAN. On each LAN / HAN, the fourth
   octet "mmm" of 192.168.nnn.mmm/32 continues to be used by the RG1 to
   identify the IoTs it serves. This is how common RGs are being
   configured today anyway (Factory default values of nnn are usually 0,
   1, 2, 10, etc.)

   2.2.2.   The right portion of Figure 9 is labeled EzIP-4. Here SPR4
   assigns the full range of the available 192.168/16 IP addresses (the
   third and fourth octets) individually to T4a through T4z.
   Consequently, these IoTs are directly accessible from any remote
   device on the Internet.

   2.2.3.   Since the existing physical connections to subscriber's
   premises do appear at the ER, it is natural to have SPRs be
   collocated with their ER. It follows that the simple routing function
   provided by the new SPR modules may be absorbed into the ER through a
   straightforward operational firmware enhancement. Consequently, the
   public - private demarcation line will remain at the RG where
   currently all utility services enter a subscriber's premises.

   2.2.4.   To identify each of these devices, we may use a three part
   address format "IPv4 - Semi-Public: TCP Port No.". The following is
   how each of the IoTs in Figure 9 may be identified.




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            RG1: 69.41.190.110-192.168.1.0

            T1a: 69.41.190.110-192.168.1.0:3

            T1z: 69.41.190.110-192.168.1.0:9

            T4a: 69.41.190.148-192.168.4.10

            T4z: 69.41.190.148-192.168.4.40

   Note that to simplify the presentation, it is assumed at this
   juncture that the conventional TCP (Transmission Control Protocol)
   [6] Port Number, normally assigned to T1a and T1z by RG1's NAT module
   upon initiating a session, equals to the fourth octet of that IoT's
   private IP address that is assigned by the RG1's DHCP (Dynamic Host
   Configuration Protocol) [7] module as ":3" and ":9", respectively.
   Such numbers are unique within each respective private network. They
   are adequate for the discussion purpose here. However, considering
   security, as well as allowing each IoT to have multiple simultaneous
   sessions, etc., this direct correlation shall be avoided in actual
   practices by following the NAT operation conventions as depicted by
   the examples in Error! Reference source not found..

       2.3. IP Header with Option Word

   To transport the EzIP Extension No., we will make use of the Option
   word in the IP header as defined in Figure 9 of [RFC791] [8]. This
   mechanism has been used for various cases in the past. Since they
   were mostly for utility or experimental purposes, however, their
   formats may be remote from the incident discussion.

       2.4. Examples of Option Mechanism

   The following two cases specifically deal with the address pool
   issues. They are referenced here to facilitate the appreciation of
   the Option mechanism.

      A. EIP (Extended Internet Protocol) - [RFC1385] [9] (Assigned but
   now deprecated Option Number = 17) by Z. Wang: This approach
   attempted to add a new network layer on top of the existing Internet
   for increasing the addressable space. Although equipment near the
   end-user would stay unchanged, equipments around the Internet Core
   Routers (CR) apparently had to go through rather involved upgrade
   procedures.

      B. EnIP (Enhanced IPv4) - Internet Draft [5] (temporarily
   utilizing Option Number = 26) by W. Chimiak: This work makes use of


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   the reserved private network addresses to extend the public pool by
   trading the private network operation for end-to-end connectivity.
   The EnIP and ExIP approaches closely resemble each other.

       2.5. Basic EzIP Header

   The basic EzIP header format uses the Option ID field to convey the
   value of the "Network No." as well as the length of the "Extension
   No.". This header has the capacity to handle up to two octets of the
   "Extension No." on either end of a connection.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|      Total Length (28)        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |                       Source Host Number                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |                  Destination Host Number                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |     EzIP      |   Extended    |   Extended    |
     6 |   (Source)    | Option Length |    Source     |    Source     |
       |   (------)    |      (4)      |     No.-1     |     No.-2     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |     EzIP      |   Extended    |   Extended    |
     7 | (Destination) | Option Length |  Destination  |  Destination  |
       |   (------)    |      (4)      |     No.-1     |     No.-2     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 11 Basic EzIP Header (Two Octet)















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   To transport an IP header for T4z at the Source end and RG1 at the
   Destination end, Figure 12 depicts an EzIP header example:

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|      Total Length (28)        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |               Source Host Number (69.41.190.148)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |            Destination Host Number (69.41.190.110)            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP-4     |     EzIP      |   Extended    |   Extended    |
     6 |   (Source)    | Option Length |    Source     |    Source     |
       |    (0X9A)     |      (4)      |    No. (4)    |    No. (40)   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP-1     |     EzIP      |   Extended    |    End of     |
     7 | (Destination) | Option Length |  Destination  |  Option List  |
       |    (0x9B)     |      (3)      |    No. (1)    |   (00000000)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 12 EzIP Header Example 1

   Note that the Option IDs 0x9A (Option Number = 26) and 0x9B (Option
   Number = 27), both representing Network No. 192.168/16 while
   conveying the Extension No.'s being two and one octet, respectively,
   in the above figure, are arbitrarily chosen from the currently
   available Option Numbers list [10]. Since RG1 extension No. has only
   one octet, the "End of Option list" Option is used to fill up word 7.
















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   If the transmission direction is reversed, types of EzIP extension
   used by the Source and the Destination will be interchanged as well.
   The unused octet will now be at the end of word 6. The "No Operation"
   Option should be used as the filler shown in Figure 13:

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|      Total Length (28)        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |               Source Host Number 69.41.190.110)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |            Destination Host Number (69.41.190.148)            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |     EzIP      |   Extended    |       No      |
     6 |   (Source)    | Option Length |    Source     |   Operation   |
       |    (0X9B)     |      (3)      |    No. (1)    |   (00000001)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |     EzIP      |   Extended    |   Extended    |
     7 | (Destination) | Option Length |  Destination  |  Destination  |
       |    (0x9A)     |      (4)      |     No. (4)   |    No. (40)   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 13 EzIP Header Example 2

       2.6. EzIP Operation

   With half a dozen of EzIP types, it would be very tedious and
   distracting to go through all combinations of IP header
   configurations and their transitions through the network. To convey
   the general scheme, Error! Reference source not found. presents
   examples of EzIP header transitions through routers among IoTs having
   EzIP-1 and EzIP-4 types of addresses, with and without EzIP
   capability.

   To introduce the EzIP approach into an environment where EzIP-unaware
   IoTs like T1a and T4a will be numerous for a long time to come, a SPR
   must be able to follow certain decision rules to determine which type
   of service to provide for achieving a smooth transition. Appendix C
   outlines such logic and related considerations.





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       2.7. Generalizing EzIP Header

   2.7.1.   The basic EzIP header shown in Figure 11 with up to two
   octet Extension No. format is not capable of EzIP-5 and EzIP-6 types
   with 20 and 24 bit, respectively. One extra octet is needed on each
   end of such a connection. An additional word in the header, however,
   will have two octets unused. To take advantage of this spare
   resource, we might as well consider a header format shown in Figure
   14 that can transport the full 4 octet (32 bit) extension addresses
   of both ends. This is similar as the EnIP header [5], except more
   flexible by allowing EzIP type being independent of that at the other
   end.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (8)|Type of Service|      Total Length (32)        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |                      Source Host Number                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |                    Destination Host Number                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |     EzIP      |   Extended    |   Extended    |
     6 |   (Source)    | Option Length |    Source     |    Source     |
       |    (0X9A)     |      (6)      |     No.-1     |     No.-2     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Extended    |   Extended    |    EzIP ID    |     EzIP      |
     7 |    Source     |    Source     | (Destination) | Option Length |
       |     No.-3     |     No.-4     |     (0X9A)    |      (6)      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Extended    |   Extended    |   Extended    |   Extended    |
     8 |  Destination  |  Destination  |  Destination  |  Destination  |
       |     No.-1     |     No.-2     |     No.-3     |     No.-4     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 14 Full EzIP Header (Four octet)

   2.7.2.   In brief, Figure 12 or Figure 13 with seven words (40%
   overhead) having two octet capacity is suitable to transport EzIP-1
   through EzIP-4 types consisting of one or two octet Extension No.
   EzIP-5 and EzIP-6 require the next IP header size which is eight
   words (60% overhead) as shown in Figure 14.



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   2.7.3.   Being a superset, utilizing "No Operation" or "End of Option
   List" type of fillers, Figure 14 is capable of handling information
   for EzIP-1 through EzIP-4 just as well. The question then becomes;
   whether the extra 20% overhead when handling EzIP-1 through EzIP-4
   headers is tolerable? If so, the single Figure 14 format may be used
   for all EzIP cases.

   2.7.4.   With the "Network No." prefixes of the well-know private
   network addresses all explicitly carried by the IP header of every
   packet as shown in Figure 14, the Option Number only needs to
   identify the length of the "Extended No.". Consequently, one Option
   Number is sufficient to represent EzIP-1 through EzIP-3 that only the
   first available octet is used for the Extension No. Similarly, one
   single Option Number representing EzIP-4 through EzIP-6 conveys the
   condition that all available bits are to be used for Extension No.

   2.7.5.   One potential drawback of the full four octet EzIP header is
   that it may cause Internet routers to intercept a packet for
   containing a disallowed (private network) IP address, although
   positioned at a location of the header normally not designated for
   address information.

   2.7.6.   By harmonizing EzIP-4 to -6 (EnIP) with EzIP-1 to -3 (ExIP)
   into one common (EzIP) format, enjoying which operating
   characteristics will simply be the result of a user subscribing to an
   EzIP address type appropriate for how he wishes to use his IoT.

   3. EzIP Deployment Strategy

   Although the eventual goal of the SPR is to support both web server
   access by IoTs from behind private networks and direct end-to-end
   connectivity between IoTs, the former application should be addressed
   first to immediately relieve the basic address shortage issue. Once
   the IoTs on both ends of an intended connection are served by SPRs,
   it will be natural to realize the latter.

   A. Architecturally

   Since the design philosophy of the SPR is an inline module between
   the Internet ER (Edge Router) and the private network RG (Routing
   Gateway), SPR introduction process may be flexible.

      A.1.  SPRs may be collocated with ERs to begin providing the CGNAT
   equivalent function. This may be done immediately without affecting
   the existing Internet (edge and core) routers.  EzIP-capable IoTs
   will then take advantage of the faster bi-directional routing



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   services through the SPRs by initiating a communication session with
   an EzIP header.

      A.2.  Alternatively, a SPR may be deployed as an adjunct module
   before an existing RG to realize the same EzIP functions on private
   premises, even if the serving Internet Service Provider (ISP) has not
   enhanced ERs with the EzIP capability. This empowers individual
   subscribers to enjoy the new EzIP capability on their own.

   B. Functionally

      B.1.  First, an ISP should install SPRs in front of business web
   servers so that new routing branches may be added to support the
   additional web servers for expanding business activities.
   Alternatively, this may be achieved by deploying new web servers with
   the SPR function built-in.

      B.2.  On the subscriber side, SPRs should be deployed to relieve
   the public address shortage issue, and to facilitate the access to
   new web servers.

   C. Permanently

   In the long run, it would be best if SPRs are integrated into ERs by
   upgrading the latter's firmware to minimize the hardware.

   Appendix C details the considerations in implementing these outlines.

   4. Updating Servers to Support EzIP

   Although the IP header Option mechanism utilized by EzIP was defined
   a long time ago as part of the original IPv4 protocol, it has not
   been used much in daily traffic. Certain current Internet facilities
   were thus optimized without considering the Option mechanism. They
   need be adjusted to provide the same performance to EzIP packets.
   There are also utility type of servers need be updated to support the
   longer EzIP address. For example;

   A. Fast Path

   Internet Core Routers (CRs) are currently optimized to only provide
   the "fast-path" (through hardware line card) routing service to
   packets without Option word in the IP header [11]. This puts EzIP
   packets in a disadvantage, because EzIP packets would be put through
   the "slow path" (processed by CPU's software before giving to the
   correct hardware line card to forward), resulting in a slower
   throughput. Since the immediate goal of the EzIP is to ease the


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   address pool exhaustion issue, subscribers not demanding for high
   performance traffic may be assigned with the facility provided
   through EzIP. This gives time for Internet routers to update so that
   EzIP packets with authorized Option numbers will eventually be
   recognized for receiving the "fast-path" service.

   B. Connectivity Verification

   One frequently used utility for verifying baseline connectivity,
   commonly referred to as the "PING" function in PC terminology, needs
   be able to transport the full EzIP address that is longer than the
   standard 32 bit IPv4 address. There is an example of an upgraded TCP
   echo server in [RFC862] [12].

   C. Domain Name Server (DNS)

   Similarly, the DNS needs to expand its data format to transport the
   longer IP address created by EzIP. This already can be done under
   IPv6. Utilizing the experimental IPv6 prefix 2001:0101 defined by
   [RFC2928] [13], EzIP addresses may be transported as standardized
   AAAA records.

   These topics are discussed in more detail under the IETF Draft RFC,
   Enhanced IPv4 - V.03 [5].

   5. EzIP Enhancements

   To minimize disturbing any assigned addresses, deployed equipment and
   current operation procedures, etc., the EzIP derivations so far are
   conducted under the constraint of utilizing only the existing three
   reserved private network address blocks. Beyond such, there are other
   possibilities. In the long run, EzIP may significantly expand the
   current IPv4 public address pool through the employment of such
   additional resources outlined below.

   A. In reviewing the IP Option Number assignments [10], it is
   discovered that more than a dozen of them are currently available.
   That is, besides five numbers, 26, 27, 28, 29 & 31 that have never
   been assigned, there are eleven numbers assigned earlier but have
   been deprecated due to the end of associated experiments. If we take
   six such numbers, one to represent each of the six EzIP extension
   types, the EzIP-1 to EzIP-3 cases will multiply the IPv4 public
   address pool by a factor of 256, individually, or a combined factor
   of 768, resulting in 3,145.728B, or 3.146KB publicly assignable
   addresses. Similarly, we can use one Option Number for each of the
   EzIP-4, -5 and -6 cases to multiply IPv4 pool by 64K, 1M and 16M (a
   total of 17.1M) fold, respectively, to the combined total of 69.894MB


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   addresses. These capacities are over 63 and 1.4M times of the
   expected Year 2020 IoTs, respectively.

   B. EzIP-8:  If all Option numbers were made available, each
   representing one EzIP Network No. prefix, up to 32 private network
   address blocks, like the 10/8 could be utilized by EzIP. To determine
   the upper limit of this scenario, let's assume that we could employ
   31 additional 10/8 type address blocks, say by re-designating 11/8
   through 41/8 as private network blocks. These enable us to expand
   each existing IPv4 public address by 32 x 16M or 512M fold. Since
   this block of 512M addresses have to be removed from the basic public
   pool, the resulting total addresses will be (4.096B - 512M) x 512M,
   or 1,835MB. This is over 35M times of the predicted number of IoTs
   (50B) by Year 2020. It certainly has the capacity to deal with the
   short- to mid- term public IP address needs.

   C. The above may be condensed for a more efficient operation. For
   example, a single 224/3 block contains the same amount of 512M
   addresses may be chosen upon re-allocation of currently assigned IPv4
   public addresses so that just one Option Number may represent it. Now
   that we have freed up 31 Option numbers, we could allocate up to 31
   more /3 address blocks for EzIP operation that provides even more
   extension address resource. However, this last step will exceed the
   total capacity of the IPv4 pool. On the other hand, this line of
   reasoning leads to the next observation.

   D. EzIP-9:  One interesting consequence of the EzIP header in Figure
   144 capable of transporting the full 32 bit private network address
   is that the Extension No. may be as long as practical. That is, we
   can go to the extreme of reserving only one bit for the Network No.,
   and leaving nothing for the IoT No. With these criteria, the current
   IPv4 pool may be divided into two halves, reserving one half of it
   (about 2B addresses) as a private network with prefix equal to "1" as
   the Network No., and all trailing 31 bits designated as Extension No.
   Each of the remaining 2B addresses (with prefix equals to "0") of the
   basic IPv4 pool may then be expanded 2B times through the EzIP
   process, resulting in a total of 4BB addresses that are IPv4
   compatible and capable of full end-to-end connectivity. This is
   roughly 80M times of the Year 2020 IoTs.

   E. EzIP-7:  On the other hand, this full 32 bit EzIP addresses
   transport facility may be applied to the elusive IPv4 240/4 block
   (240/8 - 255/8) consisting of 256M addresses that has become
   "RESERVED for Future use" [14] as the result of the historical
   address assignment evolution. Since this block is not suitable for
   being used as public address, it might as well be re-classified as an
   additional (the fourth) reusable private network pool. Then, the SPR


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   may use this block as the extension address pool in the EzIP process.
   Following this approach, each current IPv4 public address may be
   multiplied by 256M times based on only one Option Number. Since the
   240/4 block could not be used for public addressing, the size of the
   publicly assignable IPv4 pool has actually been only 3.84B (4.096B -
   256M). So, the net public addressable pool created from this approach
   is 983MB (3.84B x 256M), which is over 19.6M times of the expected
   Year 2020 IoTs. This scheme is very close to EzIP-8. Although half of
   the capacity, this manifestation has the advantage of circumventing
   reassignment of public IPv4 addresses.

   The following compares various IPv4 public address pool expansion
   configurations.

    | Extension   |Option|Effect. |Expansion|Assignable| SUP/|Connect- |
    |   Scheme    | Used | AddBits| Factor  | Pub Add  | DMD |  ivity  |
    +=============+======+========+=========+==========+=====+=========+
    |         IPv4 Public Address Block Assignments Unchanged          |
    +---+---------+------+--------+---------+----------+-----+---------+
    | E | EzIP-1  |   1  |   40   |   256   |  978.69B | 19.6| PrivNet |
    | x +---------+------+--------+---------+----------+-----+---------+
    | I | EzIP-2  |   1  |   40   |   256   |  978.69B | 19.6| PrivNet |
    | P +---------+------+--------+---------+----------+-----+---------+
    |   | EzIP-3  |   1  |   40   |   256   |  978.69B | 19.6| PrivNet |
    +---+---------+------+--------+---------+----------+-----+---------+
    | E | EzIP-4  |   1  |   48   |    64K  | 244.67KB |  5K |EndToEnd |
    | n +---------+------+--------+---------+----------+-----+---------+
    | I | EzIP-5  |   1  |   52   |     1M  |   3.82MB | 77K |EndToEnd |
    | P +---------+------+--------+---------+----------+-----+---------+
    |   | EzIP-6  |   1  |   56   |    16M  |  61.17MB |  1M |EndToEnd |
    +---+---------+------+--------+---------+----------+-----+---------+
    |EzIP-7(240/4)|   1  |   60   |   256M  | 978.69MB | 20M |EndToEnd |
    +=============+======+========+=========+==========+=====+=========+
    |          IPv4 Public Address Block Assignments Adjusted          |
    +-------------+------+--------+---------+----------+-----+---------+
    |   EzIP-8    |      |        |         |          |     |         |
    |  (224/3)    |   1  |   61   |   512M  |   1.84BB | 37M |EndToEnd |
    +-------------+------+--------+---------+----------+-----+---------+
    |   EzIP-9    |      |        |         |          |     |         |
    |  (Half of   |   1  |   63   |     2B  |      4BB | 80M |EndToEnd |
    |  IPv4 Pool) |      |        |         |          |     |         |
    +=============+======+========+=========+==========+=====+=========+

      Notes:





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   a. EzIP-1 through EzIP-7 Assignable Public Addresses calculated with
   the net basic IPv4 public address pool of 3.823B after removed the
   240/4, 10/8, 172.16/12 and 192.168/16 blocks from the basic 4.096B

   b. EzIP-8 and EzIP-9 Assignable Public Addresses calculation started
   from scratch based on the full IPv4 pool of 4.096B minus only the
   specific portion used for extension purpose

   c. "SUP/DMD": Ratio of EzIP SUPplied publicly assignable addresses to
   IoT DeManD by Year 2020

   d. Each group of EzIP-1 to -3 and EzIP-4 to -6 may use only one
   Option number if "four octet" EzIP headers are used.

            Figure 15 IPv4 Address Multiplication Possibilities

   F. It is important to note that schemes summarized in Figure 15 are
   not mutually exclusive but mostly complementary. Except the last two
   cases (EzIP-8 and EzIP-9) that are intend to demonstrate the
   potential public address sizes by starting from the full 4.096B IPv4
   pool ignoring the current assignments and reservations, EzIP-1
   through EzIP-7 may be applied to the same public IPv4 address since
   they are distinguished from one another by the Option Numbers
   representing the network prefix and the number of Extension No. bits.
   These enable an ISP to offer a rich mixture of addresses for the
   subscribers to choose from.

   G. An address extended by EzIP-4 through EzIP-7 directly connecting
   an IoT to the Internet could nevertheless be replaced by a private
   network established through an RG as described at the end of Appendix
   B. The EzIP-7 can best take advantage of this approach, because the
   240/4 address block is totally segregated from the three conventional
   private network pools, thus avoiding confusing the Internet routers.
   Essentially, the subscribers, appearing as private networks and
   directly connected IoTs, will interface with a complete spherical
   layer of secondary ERs (made of the SPRs) that wraps the entire
   existing Internet within by utilizing a never assigned address pool.

   H. In summary, the EzIP technique may expand the current IPv4 public
   address pool with a wide range of multiplication factors. It may be
   256 folds while maintaining the current private network properties
   except with reduced size, and from 64K to 256M folds while offering
   direct end-to-end connectivity. In addition, multiplication factor of
   512M may be achieved with some re-assignments of the IPv4 blocks.
   Lastly, the address capacity could even become 1B times of the
   current 4B pool with fully direct end-to-end connectivity. However,
   these last two EzIP manifestations rely on significant realignments


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   of the current address blocks. In between, we could have an IPv4
   based Internet that can simultaneously support private networks along
   with directly accessible IoTs for interconnectivity and
   interoperability.

   I. Overall, EzIP-7 may be the optimum choice. It utilizes a block of
   IPv4 addresses that could not be assigned as public identifiers
   anyway. It needs only one Option Number. Furthermore, existing
   private network setups may remain intact. Essentially, EzIP-7
   introduces a new layer of routers (made of the SPRs) that expands the
   Internet address capacity by 256M fold uniformly, with minimum
   disturbance to the current Internet operations.

   6. Security Considerations

   The EzIP solution is based on an inline module called SPR that
   intends to be as transparent to the Internet traffic as possible.
   Thus, no overall system security degradation is expected.

   7. IANA Considerations

   This draft does not create a new registry nor does it register any
   values in existing registries; no IANA action is required.

   8. Conclusions

   This draft RFC describes an enhancement to IPv4 operation utilizing
   IP header Option mechanism. Because the design criterion is to
   enhance IPv4 by extending instead of altering it, the impact on
   already in-place routers and security mechanisms is minimized.

   To resolve the IPv4 public address pool exhaustion issue, a technique
   called EzIP (phonetic for Easy IPv4) making use of the reserved
   private network address blocks is proposed.

   The basic EzIP intention is to maintain the existing private network
   configuration. If an Extension No. for EzIP is chosen from the very
   end of the 32 bit reserved private network address, leading to no
   address bit available to assign on the resultant network, the IoT
   being served is directly accessible from any remote device in the
   Internet. An IoT may communicate through the Internet with either
   type of the connectivity, depending on which type of extension
   address its owner wishes to subscribe and to utilize with.

   The basic EzIP header uses two added words (or 40% overhead) to the
   IP header for transporting two octets of an Extension No. To carry
   the full four octet EzIP extension address, a third added word is


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   needed resulting in a 60% overhead. The latter, being a superset of
   the former, may be used for all EzIP cases if the extra 20% overhead
   is tolerable for cases when the larger capacity is not necessary.

   At the extreme end of the spectrum, the EzIP scheme could be
   configured to support an IPv4 compatible pool of up to 4BB addresses
   with full direct end-to-end connectivity.

   Last but not the least, the "RESERVED for Future use" 240/4 block may
   be re-classified as the fourth reusable private network pool, so that
   the SPR may use it as the EzIP extension address. This pool can
   multiply each current IPv4 public address by 256M times based on only
   one Option Number, while all existing subscriber premises setups
   (private networks and directly connected IoTs) may remain unchanged.
   This manifestation of EzIP technique may be the optimal solution to
   our needs.

   9. References

   9.1. Normative References

    (None)

   9.2. Informative References

   [1]   https://nishithsblog.files.wordpress.com/2014/04/internet-of-
         things-market-forecast.jpg

   [2]   http://stats.labs.apnic.net/ipv6

   [3]   https://ams-ix.net/technical/statistics/sflow-stats/ether-type

   [4]   http://www.avinta.com/phoenix-1/home/IETF-Draft-ExIP.pdf

   [5]   https://tools.ietf.org/html/draft-chimiak-enhanced-ipv4-03

   [6]   https://tools.ietf.org/html/rfc793

   [7]   https://www.ietf.org/rfc/rfc2131.txt

   [8]   https://tools.ietf.org/html/rfc791

   [9]   https://tools.ietf.org/html/rfc1385

   [10]  http://www.iana.org/assignments/ip-parameters/ip-
         parameters.xhtml



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   [11]  http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.477.19
         42&rep=rep1&type=pdf

   [12]  https://tools.ietf.org/html/rfc862

   [13]  https://tools.ietf.org/html/rfc2928

   [14]  http://www.iana.org/assignments/ipv4-address-space/ipv4-
         address-space.xhtml


   10. Acknowledgments

   The authors would express their deep appreciation to Dr. W. Chimiak
   for the enlightening discussions about his team's efforts and
   experiences through the EnIP development.



   This document was prepared using 2-Word-v2.0.template.dot.





























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Appendix A  EzIP System Architecture

A.1. EzIP System Part A

   The EzIP-1 and EzIP-4 portions of the EzIP system has already been
   shown as Figure 9 in the main body of this Draft document.

A.2. EzIP System Part B

   The EzIP-2 portion maintains private network operation
   characteristics, while EzIP-5 portion delivers end-to-end
   connectivity.

                                       +------+
                        Web Server     | WS0z |
                                       +--+---+
                                          |69.41.190.145
                                          |
                                          |  +-----+
                                          +--+ ER0 |
                                             +--+--+
                                                |
                                         +------+-------+
                                 +-------+   Internet   +--------+
                                 |       |(Core Routers)|        |
                              +--+--+    +--------------+     +--+--+
                        +-----+ ER2 |                   +-----+ ER5 |
                        |     +-----+                   |     +-----+
             EzIP-2     |69.41.190.120       EzIP-5     |69.41.190.158
                     +--+--+                         +--+--+
         +-----------+     +-------+       +---------+     +------+
         |     +-----+ SPR2|       |       |   +-----+ SPR5+--+   |
         |     |     +-----+       |       |   |     +-----+  |   |
         |     | ................. |       |...|              |...|
   172.16.1.0  |172.16.2.0  172.31.240.0   |   |    +---------+   |
            +--+--+                        |   |    |             |
        +---+ RG2 +--+            172.16.1.0   |    |  172.31.255.255
        |   +-----+  |                         |    |
        | Premises 2 |              +----------+    |
        |            |              |    Premises 5 |
        |172.16.2.3  |172.16.2.9    |172.16.5.10    |172.16.5.40
     +--+--+      +--+--+        +--+--+         +--+--+
     | T2a | .... | T2z |        | T5a | ....... | T5z |
     +-----+      +-----+        +-----+         +-----+

         Figure 16 EzIP System Architecture-B (172.16/12 Portion)



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A.3. EzIP System Part C

   The EzIP-3 portion maintains private network operation
   characteristics, while EzIP-6 portion delivers end-to-end
   connectivity.

                                       +------+
                        Web Server     | WS0z |
                                       +--+---+
                                          |69.41.190.145
                                          |
                                          |  +-----+
                                          +--+ ER0 |
                                             +--+--+
                                                |
                                         +------+-------+
                                 +-------+   Internet   +--------+
                                 |       |(Core Routers)|        |
                              +--+--+    +--------------+     +--+--+
                        +-----+ ER3 |                   +-----+ ER6 |
                        |     +-----+                   |     +-----+
                        |                               |
             EzIP-3     |69.41.190.130       EzIP-6     |69.41.190.160
                     +--+--+                         +--+--+
         +-----------+     +-------+       +---------+     +------+
         |     +-----+ SPR3|       |       |   +-----+ SPR6+--+   |
         |     |     +-----+       |       |   |     +-----+  |   |
         | ... | ................. |       |   |              |   |
         |     |                   |       |...|              |...|
   10.1.0.0    |10.3.0.0      10.255.0.0   |   |    +---------+   |
            +--+--+                        |   |    |             |
        +---+ RG3 +--+              10.1.0.0   |    |    10.255.255.255
        |   +-----+  |                         |    |
        | Premises 3 |              +----------+    |
        |            |              |    Premises 6 |
        |10.3.0.3    |10.3.255.9    |10.6.0.10      |10.6.0.40
     +--+--+      +--+--+        +--+--+         +--+--+
     | T3a | .... | T3z |        | T6a | ....... | T6z |
     +-----+      +-----+        +-----+         +-----+




            Figure 17 EzIP System Architecture-C (10/8 Portion)




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A.4. EzIP System Part D

   Utilizing 240/4, the EzIP provides a "spherical shell" of routable
   addresses wrapped around the entire current Internet (CRs and ERs),
   separating it from the subscribers' IoTs that are either directly
   addressable from the Internet such as T7z, T8z, or behind existing
   private networks like RG7, RG8.

                                       +------+
                        Web Server     | WS0z |
                                       +--+---+
                                          |69.41.190.145
                                          |
                                          |  +-----+
                                          +--+ ER0 |
                                             +--+--+
                                                |
                                         +------+-------+
                              ER1  ------+              +-----  ER4
             Interconnect                |              |
                 with         ER2  ------+   Internet   +-----  ER5
              Preceding                  |              |
               Figures        ER3  ------+(Core Routers)+-----  ER6
                                         |              |
                                 +-------+              +--------+
                                 |       |              |        |
                              +--+--+    +--------------+     +--+--+
                        +-----+ ER7 |                   +-----+ ER8 |
                        |     +-----+                   |     +-----+
                        |                               |
                        |69.41.190.170                  |69.41.190.180
                     +--+--+                         +--+--+
         +-----------+     +-------+       +---------+     +------+
         |     +-----+ SPR7+--+    |EzIP-7 |   +-----+ SPR8+--+   |
         | ... |     +-----+  |... |       |   |     +-----+  |   |
         |     |     +--------+    |       |...|              |...|
   240.0.0.1   |     |     255.255.255.255 |   |    +---------+   |
               |     |                     |   |    |             |
        +------+     |               240.0.0.1 |    |   255.255.255.255
        | Premises 7 |              +----------+    |
        |            |              |    Premises 8 |
        |247.0.0.3   |247.0.0.9     |248.0.0.10     |248.0.0.40
     +--+--+      +--+--+        +--+--+         +--+--+
     | RG7 | .... | T7z |        | T8z | ....... | RG8 |
     +-----+      +-----+        +-----+         +-----+

           Figure 18 EzIP System Architecture-D (240/4 Portion)


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   +--------------------------+-----------------+----------------+
   |                          |   Basic IPv4    |  EzIP-capable  |
   +--------------------------+-----------------+----------------+
   |                          |  ER0, ER1, ER2, |  ------------  |
   | Internet Edge Router (ER)|  ER3, ER4, ER5, |                |
   |                          |  ER6, ER7, ER8  |                |
   +--------------------------+-----------------+----------------+
   |                          |  T1a, T2a, T3a, | T1z, T2z, T3z, |
   | Internet of Things (IoT) |  T4a, T5a, T6a, | T4z, T5z, T6z, |
   |                          |                 | T7z, T8z       |
   +--------------------------+-----------------+----------------+
   |                          |  RG1, RG2, RG3  |                |
   | Routing Gateway (RG)     |  RG7, RG8       |  ------------  |
   +--------------------------+-----------------+----------------+
   |                          |  -------------  |   SPR1, SPR2,  |
   | Semi-Public Router (SPR) |                 |   SPR3, SPR4,  |
   |                          |                 |   SPR5, SPR6,  |
   |                          |                 |   SPR7, SPR8   |
   +--------------------------+-----------------+----------------+
   | Web Server (WS)          |  -------------  |      WS0z      |
   +--------------------------+-----------------+----------------+



   Note: WS0z could be either a collection of conventional web servers
   connected to the Internet via a SPR, with message transfer capability
   among themselves, or a new web sever with multiple modules that
   recognize and re-direct packets depending on its header (conventional
   IP or EzIP) type. The main path functions the same as existing web
   servers. The secondary servers are on EzIP extension addresses that
   may be directly accessed by packets with EzIP header, or receive
   packets forwarded through the main module upon being qualified.



                     Figure 19 EzIP System Components













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Appendix B  EzIP Operation

   To demonstrate how EzIP could support and enhance the Internet
   operations, the following are three connection examples that involve
   SPRs as shown in Figure 9. These present a general perspective of how
   IP header transitions through the routers may look like.

   A. The first example is between EzIP-unaware IoTs, T1a and T4a. This
   operation is very much like the conventional TCP/IP packet
   transmission except with SPRs acting as an extra pair of routers
   supported by CGNAT. In addition, SPR4 may be viewed as a full-fledged
   RG minus DHCP and NAT support, because it assigns its IoTs with
   static addresses from the entire range of reserved 192.168/16,
   instead of the common much smaller pool of 192.168.nnn/24.

   B. The second one is between EzIP-capable IoTs, T1z and T4z. Here,
   the SPRs process the extended public IP addresses in router mode,
   avoiding the delays due to the NAT type of operations.

   C. The last one is between EzIP-unaware and EzIP-capable IoTs. By
   initiating and responding with a conventional IP header, T1z and T4z
   behave like an EzIP-unaware IoT. Thus, all packet exchanges use the
   conventional IP headers, just like case A. above.

B.1. Connection between EzIP-unaware IoTs

B.1.1. T1a Initiates a Session Request towards T4a

   In Figure 20, T1a initiates a session request to SPR4 that serves T4a
   by sending an IP packet to RG1. There is no TCP port number in this
   IP header yet.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (5)|Type of Service|       Total Length (20)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (192.168.1.3)                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.148)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                   Figure 20 IP Header: From T1a to RG1


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B.1.2. RG1 Forwards the Packet to SPR1

     In Figure 21, RG1, allowing be masqueraded by T1a, relays the
   packet toward SPR1 by assigning the TCP Source port number, 3N, to
   T1a. Note that the suffix "N" denotes the actual TCP port number
   assigned by the RG1's NAT. This could assume multiple values, each
   represents a separate communications session that T1a is engaged in.
   A corresponding entry is created in the state table for handling the
   responding packet from the Destination site. Since T4a's TCP port
   number is not known yet, it is filled with all 1's.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (192.168.1.0)                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.148)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |       Source Port (3N)        |   Destination Port (All 1's)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 21 TCP/IP Header: From RG1 to SPR1





















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B.1.3. SPR1 Sends the Packet to SPR4 through the Internet

   In Figure 22, SPR1 allowing masqueraded by RG1 (with the Source Host
   Number changed to be its own and the TCP port number changed to 1C,
   where "C" stands for CGNAT) sends the packet out through the Internet
   towards SPR4. The packet traverses through the Internet (ER1, CR and
   ER4) utilizing only the basic IP header portion of address
   information (words 4 & 5).

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |             Source Host Number (69.41.190.110)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.148)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |       Source Port (1C)        |   Destination Port (All 1's)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 22 TCP/IP Header: From SPR1 to SPR4





















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B.1.4. SPR4 Sends the Packet to T4a

   Since the packet has a conventional IP header without Destination TCP
   port number, SPR4 would ordinarily drop it due to the CGNAT function.
   However, for this example, let's assume that there exists a state-
   table that was set up by a DMZ process for redirecting this packet to
   T4a with a CGNAT TCP port number 410C (the composite of the third and
   the fourth octets, "4.10" of T4a's Extension No.). In Figure 23, SPR4
   sends the packet to T4a by constructing the destination address
   accordingly.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |             Source Host Number (69.41.190.110)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (192.168.4.10)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |       Source Port (1C)        |      Destination Port (410C)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 23 TCP/IP Header: From SPR4 to T4a



















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B.1.5. T4a Replies to SPR4

   In Figure 24, when T4a replies to SPR4, it interchanges the Source
   and Destination identifications to create an IP header for the reply
   packet.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (192.168.4.10)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.110)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |      Source Port (410C)       |     Destination Port (1C)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 24 TCP/IP Header: From T4a to SPR4
























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B.1.6. SPR4 Sends the Packet to SPR1 through the Internet

   In Figure 25, SPR4 sends the packet toward SPR1 with the following
   header through the Internet (ER4, CR and ER1) who will simply relay
   the packet according to the information in word 5 (Destination Host
   Number):

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (69.41.190.148)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.110)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |      Source Port (410C)       |     Destination Port (1C)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 25 TCP/IP Header: From SPR4 to SPR1























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B.1.7. SPR1 Sends the Packet to RG1

   In Figure 26, RG1 address is reconstructed by using the information
   in the CGNAT state-table stored in SPR1.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (69.41.190.148)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |            Destination Host Number (192.168.1.0)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |       Source Port (410C)      |     Destination Port (3N)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 26 TCP/IP Header: From SPR1 to RG1

























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B.1.8. RG1 Forwards the Packet to T1a

   In Figure 27, T1a address is reconstructed from that of RG1 and the
   state-table in the NAT based on Destination Port (3N).

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (69.41.190.148)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |            Destination Host Number (192.168.1.3)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |      Source Port (410C)       |     Destination Port (3N)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 27 TCP/IP Header: From RG1 to T1a

B.1.9. T1a Sends a Follow-up Packet to RG1

   To carry on the communication, T1a in Figure 28 sends the follow-up
   packet to RG1 with a full TCP/IP header.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (6)|Type of Service|       Total Length (24)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |                Source Host Number (192.168.1.3)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |            Destination Host Number (69.41.190.148)            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     6 |       Source Port (3N)        |    Destination Port (410C)    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

        Figure 28 TCP/IP Header: Follow-up Packets From T1a to RG1


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B.2. Connection Between EzIP-capable IoTs

   The following is an example of EzIP operation between T1z and T4z
   shown in Figure 9. Each knows its own full "Public - EzIP : Private"
   network addresses, "69.41.190.110-192.168.1.0:9" and "69.41.190.148-
   192.168.4.40", respectively, as well as the other's. Note that T4z
   full address does not have the IoT No. portion. It is directly
   addressable from the Internet.

B.2.1. T1z Initiates a Session Request towards T4z

   T1z initiates a session request to T4z by sending an EzIP packet to
   RG1. There is no TCP port number word, because T4z does not have such
   and that for T1z has not been assigned by the RG1's NAT.

       0                   1                   2                   3
       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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (28)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (192.168.1.9)                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.148)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |       No      |
     6 |   (Source)    | Option Length |    Source     |   Operation   |
       |    (0X9B)     |      (3)      |     No. (1)   |   (00000001)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     7 | (Destination) | Option Length |  Destination  |  Destination  |
       |    (0X9A)     |      (4)      |     No. (4)   |     No. (40)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 29 EzIP Header: From T1z to RG1

   Note that 0X9A and 0X9B are temporarily selected from the available
   "IP Option Numbers" [10]. They were employed by prior efforts to
   facilitate the presentation of, EnIP and ExIP, respectively. These
   convey the concepts of transporting the value of the "Network No." as
   well as the number of octets needed in the "Extension No.". That is,
   both Option Numbers represent 192.168/16 as the EzIP Network No.
   prefix, while individually conveys two or one octets used in the
   Extension No., respectively.


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B.2.2. RG1 Forwards the Packet to SPR1

     In Figure 30, RG1, allowing to be masqueraded by T1z, relays the
   packet toward SPR1 by assigning the TCP Source port number, 9N, to
   T1z. Since T4z is directly connected to the Internet, there is no
   private network information to fill the Destination portion of the
   TCP word.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (192.168.1.0)                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.148)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |       No      |
     6 |   (Source)    | Option Length |    Source     |   Operation   |
       |    (0X9B)     |      (3)      |     No. (1)   |   (00000001)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     7 | (Destination) | Option Length |  Destination  |  Destination  |
       |    (0X9A)     |      (4)      |     No. (4)   |     No. (40)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |       Source Port (9N)        |   Destination Port (All 1's)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 30 TCP/EzIP Header: From RG1 to SPR1
















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B.2.3. SPR1 Sends the Packet to SPR4 through the Internet

   In Figure 31, SPR1 sends the packet out into the Internet towards
   SPR4. The packet traverses through the Internet (ER1, CR and ER4),
   utilizing only the basic IP header portion of address information.
   Note that the third octet of word 6 plus the first two octets of word
   8 make up the subnet address of T1z. And, the last two octets of word
   7 represent the extended address of T4z.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |             Source Host Number (69.41.190.110)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.148)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |       No      |
     6 |   (Source)    | Option Length |    Source     |   Operation   |
       |    (0X9B)     |      (3)      |     No. (1)   |   (00000001)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     7 | (Destination) | Option Length |  Destination  |  Destination  |
       |    (0X9A)     |      (4)      |     No. (4)   |     No. (40)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |       Source Port (9N)        |   Destination Port (All 1's)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 31 TCP/EzIP Header: From SPR1 to SPR4













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B.2.4. SPR4 Sends the Packet towards T4z to RG2

   In Figure 32, SPR4 sends the packet to RG2 by reconstructing its
   address from the Option number and the Extended Destination No.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |             Source Host Number (69.41.190.110)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (192.168.4.40)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |       No      |
     6 |   (Source)    | Option Length |    Source     |   Operation   |
       |    (0X9B)     |      (3)      |     No. (1)   |   (00000001)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     7 | (Destination) | Option Length |  Destination  |  Destination  |
       |    (0X9A)     |      (4)      |     No. (4)   |     No. (40)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |       Source Port (9N)        |   Destination Port (All 1's)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 32 TCP/EzIP Header: From SPR4 to T4z

















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B.2.5. T4z Replies to SPR4

   In Figure 33, T4z replies to SPR4 with the full T1z identification
   (69.41.190.110-192.68.1.0:192.168.1.9N conveyed by Option ID 0X9B
   together with the compact address string 69.41.190.110-1:9N) to
   create an EzIP header for the reply packet.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (192.168.4.40)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.110)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     6 |   (Source)    | Option Length |    Source     |    Source     |
       |    (0X9A)     |      (4)      |     No. (4)   |     No. (40)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |     End of    |
     7 | (Destination) | Option Length |  Destination  |     Option    |
       |    (0X9B)     |      (3)      |    No. (1)    |   (00000000)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |      Source Port (All 1's)    |     Destination Port (9N)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 33 TCP/EzIP Header: From T4z to SPR4















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B.2.6. SPR4 Sends the Packet to SPR1 through the Internet

   In Figure 34, SPR4 sends the packet toward SPR1 with the following
   header through the Internet (ER2, CR, and ER1) who will simply relay
   the packet according to the information in word 5 (Destination Host
   Number):

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (69.41.190.148)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |           Destination Host Number (69.41.190.110)             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     6 |   (Source)    | Option Length |    Source     |    Source     |
       |    (0X9A)     |      (4)      |     No. (4)   |     No. (40)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |    End of     |
     7 | (Destination) | Option Length |  Destination  |    Option     |
       |    (0X9B)     |      (3)      |     No. (1)   |   (00000000)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |      Source Port (All 1's)    |     Destination Port (9N)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 34 TCP/EzIP Header: From SPR4 to SPR1















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B.2.7. SPR1 Sends the Packet to RG1

   In Figure 35, RG1 address is reconstructed from the Option number and
   the Extended Destination No.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (69.41.190.148)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |            Destination Host Number (192.168.1.0)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     6 |   (Source)    | Option Length |    Source     |    Source     |
       |    (0X9A)     |      (4)      |     No. (4)   |    No. (40)   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |    End of     |
     7 | (Destination) | Option Length |  Destination  |    Option     |
       |    (0X9B)     |      (3)      |     No. (1)   |   (00000000)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |      Source Port (All 1's)    |     Destination Port (9N)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 35 TCP/EzIP Header: From SPR1 to RG1

















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B.2.8. RG1 Forwards the Packet to T1z

   In Figure 36, T1z address is reconstructed from that of RG1 and the
   NAT state-table based on Destination Port (9N).

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (69.41.190.148)               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |            Destination Host Number (192.168.1.9)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     6 |   (Source)    | Option Length |    Source     |    Source     |
       |    (0X9A)     |      (4)      |     No. (4)   |    No. (40)   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |    End of     |
     7 | (Destination) | Option Length |  Destination  |    Option     |
       |    (0X9B)     |      (3)      |     No. (1)   |   (00000000)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |      Source Port (All 1's)    |     Destination Port (9N)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 36 TCP/EzIP Header: From RG1 to T1z

















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B.2.9. T1z Sends a Follow-up Packet to RG1

      In Figure 37, T1z sends a follow-up packet to RG1 with all fields
   filled with needed information.

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     1 |Version|IHL (7)|Type of Service|       Total Length (32)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     2 |        Identification         |Flags|     Fragment Offset     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     3 | Time to Live  |    Protocol   |        Header Checksum        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     4 |              Source Host Number (192.168.1.9)                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     5 |          Destination Host Number (69.41.190.148)              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |     No Op     |
     6 |   (Source)    | Option Length |    Source     |     Option    |
       |    (0X9B)     |      (3)      |    No. (1)    |   (00000001)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    EzIP ID    |      EzIP     |   Extended    |   Extended    |
     7 | (Destination) | Option Length |  Destination  |  Destination  |
       |    (0X9A)     |      (4)      |     No. (4)   |    No. (40)   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     8 |      Source Port (9N)         |   Destination Port (All 1's)  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 37 TCP/EzIP Header: Follow-up Packets from T1z to RG1

B.3. Connection Between EzIP-unaware and EzIP-capable IoTs

B.3.1. T1a initiates a request to T4z

   Since T1a can create only IP header with conventional format, the
   SPRs will provide CGNAT type of services to the IP packets. And,
   assuming SPR4 has a state-table set up by DMZ for forwarding the
   request to T4z, the packet will be delivered to T4z. Seeing the
   incoming packet using conventional IP header, T4z should respond with
   the same so that the session will be conducted with conventional
   TCP/IP headers.





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B.3.2. T1z initiates a request to T4a

   Knowing T4a is not capable of EzIP header, T1z purposely initiates
   the request packet using conventional IP header. It will be treated
   by SPRs in the same manner as the T1a initiated case above and
   recognizable by T4a.

   In brief, the steps outlined above are very much the same as the
   conventional TCP/IP header transitions between routers, except two
   extra steps in each direction are inserted to encode and decode the
   additional SPR provided EzIP routing process.

   Note that when an IoT, such as T4a or T4z, is directly connected to a
   SPR, like SPR4, there is no RG in-between. There is no corresponding
   TCP port number in word 8 of the above TCP/EzIP headers. This spare
   facility in the header allows an RG be inserted if desired, thus re-
   establishing the private network environment.

   When only its Extension No. portion of an EzIP extension address is
   transported in the EzIP header, the conventional private network
   address may be reused in this kind of added private networks. When
   extension address is transported by a full TCP/EzIP header with four
   octet format, proper precaution must be exercised to avoid confusing
   the routers along the way due to the appearance of a full private
   network address although at a location in the IP header not intended
   for ordinary IP address. When EzIP-7 is used, this is not of concern
   because the 240/4 block does not belong to the three conventional
   private network address blocks.





















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Appendix C  Internet Transition Considerations

   To enhance a large communication system like the Internet, it is
   important to minimize the disturbance to the existing equipments and
   processes due to any needed modification. The basic EzIP plan is to
   confine all actionable enhancements within the new SPR module. The
   following outlines the considerations for supporting the transition
   from the current Internet to the one enhanced by the EzIP technique.

C.1. EzIP Implementation

   C.1.1.   Introductory Phase:

   A. Insert an SPR in front of a web-server that desires to have
   additional subnet addresses for offering diversified activities. For
   the long term, a new web server may be designed with these two
   functional modules combined.

      .  The first address of a private network address pool, e.g.,
   192.168.0.0, used by the SPR should be reserved as a DMZ (De-
   Militarized Zone) channel directing the initial incoming service
   requesting packets to the existing web server. This will maintain the
   same operation behavior projected to the general public.

      .  The additional addresses, up to 192.168.255.255 may be used for
   EzIP address extension purposes. Each may be assigned to an
   additional web server representing one of the business's new
   activities. Each of these new servers will then respond with EzIP
   header to messages forwarded from the main server, or be directly
   accessed through its EzIP address.

   B. Insert an SPR in front of a group of subscribers who are to be
   served with the EzIP function. The basic service provided by this SPR
   will be the CGNAT equivalent function. This will maintain the same
   baseline user experience in accessing the Internet.

   C. Session initiating packets with basic IPv4 header will be routed
   by SPRs to a business's existing server at the currently published
   IPv4 public address (discoverable by existing DNS). The server should
   respond with the basic IPv4 format as well. Essentially, this
   maintains the existing interaction between a user and a web server
   within an EzIP-unaware environment.

      So far, neither the web-server nor any subscriber's IoTs needs to
   be enhanced, because the operations remain pretty much the same as
   today's common practice utilizing CGNAT assisted connectivity. See
   Appendix B.1. for an example.


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   D. Upon connected to the main web server, if a customer intentionally
   selects one of the new services offered by the primary web-server,
   the web-server will ask the customer to confirm the selection.

      .  If confirmed, implying that the customer is aware of the fact
   that his IoT is being served by an SPR, the web server forwards the
   request to a branch server for carrying on the communication via an
   EzIP address.

      .  The SPR at the originating side, recognizing the EzIP header
   from the web-server, replaces the CGNAT service with EzIP routing.

      .  For all subsequent packets exchanged, the EzIP headers will be
   used in either direction. See Appendix B.2. for an example. This will
   speed up the transmission throughput performance for the rest of the
   session.

   C.1.2.   New IoT Operation Modes:

   A. EzIP-capable IoT will create EzIP header in initiating a session,
   to directly reach a specific web-server, instead of the lengthy steps
   of going through the DMZ port followed by manually making the
   selection from the main web server. This will speed up the initial
   handshake process. See Appendix B.2. for an example.

   B. To communicate with an EzIP-unaware IoT, an EzIP-capable IoT
   should purposely initiate a session with conventional IP header. This
   will signal the SPRs to provide just CGNAT type of connection
   service. See Appendix B.3. for an example.

   C.1.3.   End-to-End Operation:

   Once EzIP-capable IoTs become common for the general public, direct
   communication between any pair of such IoTs will be achievable. An
   EzIP-capable IoT, knowing the other IoT's full EzIP address, may
   initiate a session by creating an EzIP header that directs the SPRs
   to provide EzIP services, bypassing the CGNAT process. See Appendix
   B.2. for an example.

C.2. SPR Operation Logic

   To support the above scenarios, the SPR should be designed with the
   following decision process:

   C.2.1. Initiating a Session Request for an IoT or via a RG




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   If a session request IP packet contains EzIP Option word, it will be
   routed forward by SPR accordingly. Otherwise, the SPR provides CGNAT
   service by assigning a TCP port number to the packet and allowing the
   packet to masquerade with the SPR's own IP address while an entry to
   the state (port forward / look-up / hash) table is created in
   anticipation of the reply packet.

   C.2.2.   Receiving a Session Request from the ER

   If a received IP packet includes a valid EzIP Option word or port
   number, SPR will utilize it to route the packet to an RG or an IoT.
   For a packet with plain IP header, it will be routed according to the
   Destination Host Number (IP header word 5).

C.3. RG Enhancement

   With IPv4 address pool expanded by the EzIP schemes, there will be
   sufficient publicly assignable addresses for IoTs wishing to be
   directly accessible. The existing private networks may continue their
   current behavior of blocking session request packets from the
   Internet. In-between, another connection mode is possible. The
   following describes such an option in the context of the existing RG
   operation conventions.

   C.3.1.   Initiating Session request for an IoT

   Without regard to whether the IP header is a conventional one or an
   EzIP type, a RG allows a packet to masquerade with the RG's own IP
   address by assigning a TCP port number to the packet and creating an
   entry to the state (port forward / look-up / hash) table. This is the
   same as current NAT practice.

   C.3.2.   Receiving a packet from the SPR

   The "Destination Port" value in the packet is examined:

      A. If it matches with an entry in the RG NAT's state-table, the
   packet is forward to the corresponding address. This is the same as
   the normal NAT processes in a conventional RG.

      B. If it matches with the address of an active IoT on the private
   network, the packet is assigned with a TCP port number and then
   forwarded to that IoT.

   Note that there is certain amount of increased security risk with
   this added last step, because a match between a guessed destination
   identity and the above two lists could happen by chance. To address


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   this issue, the following proactive mechanism may be incorporated in
   parallel:

   If the "Destination Port" number is null or does not match with
   either of the above cases, the packet is dropped and an alarm state
   is activated to monitor for possible ill-intended follow-up attempts.
   A defensive mechanism should be triggered when the number of failed
   attempts has exceeded the preset threshold within a finite time
   interval.

   In brief, if the IP header of a session requesting packet indicates
   that the sender knows the identity of the desired destination IoT on
   a private network, the common RG screening process will be bypassed.
   This facilitates the direct end-to-end connection, even in the
   presence of the NAT. Note that this process is very much the same as
   the AA (Automated Attendant) capability in a PABX telephone switching
   system that automatically makes the connection for a caller who
   indicates (via proper secondary dialing or the equivalent) knowing
   the extension number of the destination party. Such process can
   effectively screen out most of the unwanted callers.







Authors' Addresses

   Abraham Y. Chen
   Avinta Communications, Inc.
   142 N. Milpitas Blvd., #148, Milpitas, CA 95035-4401 US

   Phone: _+1(408)942-1485
   Email: AYChen@Avinta.com


   Ramamurthy R. Ati
   Avinta Communications, Inc.
   142 N. Milpitas Blvd., #148, Milpitas, CA 95035-4401 US

   Phone: _+1(408)458-7109
   Email: ramaati18@gmail.com






Chen, Ati               Expires June 13, 2017                 [Page 52]


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