Adaptive IPv4 Address Space
draft-chen-ati-adaptive-ipv4-address-space-10
<Network Working Group> A. Y. Chen
Internet Draft R. R. Ati
Intended status: Experimental Avinta Communications, Inc.
Expires: June 2022 A. Karandikar
India Institute of Technology
D. R. Crowe
Wireless Telcom Consultant
December 8, 2021
Adaptive IPv4 Address Space
draft-chen-ati-adaptive-ipv4-address-space-10.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), outlines the IPv4 public address pool expansion and the
Internet system architecture enhancement considerations. EzIP may
expand an IPv4 address by a factor of 256M without affecting the
existing IPv4 based Internet, or the current private networks. It is
in full conformance with the IPv4 protocol, and supports not only
both direct and private network connectivity, but also their
interoperability. EzIP deployments may coexist with existing Internet
traffic and IoTs (Internet of Things) operations without perturbing
their setups, while offering end-users the freedom to indepdently
choose which service. EzIP may be implemented as a software or
firmware enhancement to Internet edge routers or private network
routing gateways, wherever needed, or simply installed as an inline
adjunct hardware module between the two, enabling a seamless
introduction. The 256M case detailed here establishes a complete
spherical layer of an overlay of routers for interfacing between the
Internet fabic (core plus edge routers) and the end user premises or
IoTs. Incorporating caching proxy technology in the gateway, a fairly
large geographical region may enjoy address expansion based on as few
as one ordinary IPv4 public address utilizing IP packets with
degenerated EzIP header. If IPv4 public pool allocations were
reorganized, the assignable pool could be multiplied 512M fold or
even more. Enabling hierarchical address architecture which
facilitates both hierarchical and mesh routing, EzIP can provide
nearly the same order of magnitude of address pool resources as IPv6
while streamlining the administrative aspects of it. The basic EzIP
will immediately resolve the local IPv4 address shortage, while being
transparent to the rest of the Internet as a new parallel facility.
Under the Dual-Stack environment, these proposed interim facilities
will relieve the IPv4 address shortage issue, while affording IPv6
more time to reach maturity for providing the availability levels
required for delivering a long-term general service.
Table of Contents
1. Introduction...................................................4
1.1. Contents of this Draft....................................6
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2. EzIP Overview..................................................6
2.1. EzIP Numbering Plan.......................................6
2.2. Analogy with NAT..........................................8
2.3. EzIP System Architecture..................................9
2.4. IP Header with Option Word...............................11
2.5. Examples of Option Mechanism.............................12
2.6. EzIP Header..............................................13
2.7. EzIP Operation...........................................14
3. EzIP Deployment Strategy......................................14
4. Updating Servers to Support EzIP..............................17
5. EzIP Enhancement and Application..............................18
6. Security Considerations.......................................22
7. IANA Considerations...........................................22
8. Conclusions...................................................22
9. References....................................................23
9.1. Normative References.....................................23
9.2. Informative References...................................23
10. Acknowledgments..............................................24
Appendix A EzIP Operation.......................................25
A.1. Connection between EzIP-unaware IoTs.....................25
A.1.1. T1a Initiates a Session Request towards T4a.........25
A.1.2. RG1 Forwards the Packet to SPR1.....................26
A.1.3. SPR1 Sends the Packet to SPR4 through the Internet..27
A.1.4. SPR4 Sends the Packet to T4a........................28
A.1.5. T4a Replies to SPR4.................................29
A.1.6. SPR4 Sends the Packet to SPR1 through the Internet..30
A.1.7. SPR1 Sends the Packet to RG1........................31
A.1.8. RG1 Forwards the Packet to T1a......................32
A.1.9. T1a Sends a Follow-up Packet to RG1.................32
A.2. Connection Between EzIP-capable IoTs.....................33
A.2.1. T1z Initiates a Session Request towards T4z.........33
A.2.2. RG1 Forwards the Packet to SPR1.....................34
A.2.3. SPR1 Sends the Packet to SPR4 through the Internet..35
A.2.4. SPR4 Sends the Packet to T4z........................36
A.2.5. T4z Replies to SPR4.................................37
A.2.6. SPR4 Sends the Packet to SPR1 through the Internet..38
A.2.7. SPR1 Sends the Packet to RG1........................39
A.2.8. RG1 Forwards the Packet to T1z......................40
A.2.9. T1z Sends a Follow-up Packet to RG1.................41
A.3. Connection Between EzIP-unaware and EzIP-capable IoTs....42
A.3.1. T1a Initiates a Request to T4z......................42
A.3.2. T1z Initiates a Request to T4a......................42
Appendix B Internet Transition Considerations...................43
B.1. EzIP Implementation......................................43
B.2. SPR Operation Logic......................................44
B.3. RG Enhancement...........................................45
Appendix C EzIP Realizability...................................47
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C.1. 240/4 Netblock Capable IoTs..............................47
C.2. 240/4 Netblock Capable Routers...........................47
C.3. Enhancing an RG..........................................48
C.4. SPR Reference Design.....................................49
C.5. RAN Deployment Model.....................................49
Appendix D Enhancement of a Commercial RG.......................51
D.1. Candidate Code for Modification..........................51
D.2. Proposed Modification....................................51
D.3. Performance Verification.................................52
Appendix E Utilizing Open Source Router Code....................53
E.1. EzIP Realizability Test Bed..............................53
E.2. RAN Architecture Demonstration...........................53
E.3. EzIP Compatible Routers..................................54
Appendix F Sub-Internet.........................................55
F.1. Gateway Configuration....................................55
F.2. Gateway Setup............................................55
F.3. Sub-Internet Operation...................................55
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 upon any other directly.
IP addresses are needed while client devices, such as mobile phones,
are attached to the internet, which is a rapidly increasing demand.
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 configuration.
By Year 2020, the world population and number of IoTs are expected to
reach 7.6B (Billion) and 50B respectively, according to a 2011 Cisco
online white paper [3].
The IPv4 dot-decimal address format, consisting of four octets each
made of 8 binary bits, provides a little over 4 billion unique
addresses (256 x 256 x 256 x 256 equals 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 (Million), or 4.096B (or, further rounded down
to 4B for quick estimate calculations). Clearly, the predicted demand
is more than 12 times over the inherent capacity available from the
supply.
IPv6, with its 128-bit hexadecimal address format, is four times as
long as the IPv4, has 256BBBB (4B x 4B x 4B x 4B) unique addresses.
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It offers a promising solution to the address shortage. However, its
global adoption appears to be facing significant challenges [4], [5].
Interim relief to the IPv4 address shortage has been provided by
Network Address and Port Translation (NAPT - commonly known simply as
NAT) on private networks together with Carrier Grade NAT (CG-NAT or
abbreviated further to CGN) [RFC6598] [6] over the public Internet.
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 own clients, impeding the end-to-end setup requests initiated
from remote devices that a fully functional communication system
should be capable of. Since port numbers are used to effectively
increase the size of the address pool, they introduce complex and
suboptimal port management requirements. For example, being dynamic,
the state-table used by CG-NAT increases CyberSecurity vulnerability
by imposing extra efforts to forensic tracing of perpetrators. On the
other hand, private network NAT as part of a Routing / Residential
Gateway (RG) does provide a rudimentary defense against intrusion. To
minimize the confusion, we will explicitly label this latter
(although implemented first) NAT as RG-NAT in this document to
distinguish from the CG-NAT.
If IPv4 capacity could be expanded without the CG-NAT limitations,
such as size, speed and outgoing-only, the urgency due to address
shortage will be relaxed long enough for the IPv6 to mature on its
own pace.
There have been several proposals to increase the effective Internet
public address pool in the past. They all introduced new techniques
or protocols that ran into certain handicaps or compatibility issues,
preventing a smooth transition.
EzIP utilizes a long-reserved network address block (netblock) 240/4
[7] that all of the existing Internet Core (/ backbone) Router (CR),
Edge Router (ER) and private network Routing (/ Residential) Gateway
(RG) as well as terminal hosts such as PCs and IoTs are not allowed
to utilize. The Option mechanism defined in [RFC791] [1] is used for
transporting such information as the IP header payload so that an IP
packet is transparent to all of these routers, except a newly defined
category named Semi-Public Router (SPR). By inserting an SPR between
an ER and a private premises that it serves, each publicly assignable
address can be expanded 256M fold.
EzIP introduces minimal perturbation by being compatible to the
current Internet system architecture. Its deployment will start with
an SPR providing public CG-NAT functions to unload the burden from
the current CG-NAT facility. With the basic routing as an integral
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part of the SPR, directly connected individual IoTs and private
networks will be encouraged to migrate toward the full EzIP service
for enjoying the end-to-end connectivity between and among them.
1.1. Contents of this Draft
This draft outlines the EzIP numbering plan. An enhanced IP header,
called EzIP header, is introduced to carry the EzIP address as
payload using the Option word. How the Internet architecture will
change as the result of being extended by the EzIP scheme is
explained. How the EzIP header flows through various routers, and
Internet update considerations are described, with details presented
in Appendices A and B, respectively. Utilizing the EzIP approach,
several ways to expand the publicly assignable IPv4 address pool, as
well as enhance Internet operations are then discussed. Appendix C
outlines the experimental effort to demonstrate the feasibility of
EzIP by configuring a regional area network model based on current
networking equipment upon finite enhancements. Appendix D is a Work-
In-Progress report about the enhancement of a specific commercial RG.
Appendix E is an EzIP scheme feasibility demonstration by utilizing
publicly available hardware and software. Appendix F describes a
networking configuration called Sub-Internet that is based on one
single IPv4 address. A sub-Internet is a self-content module that can
provide Internet-like services to a stand-alone region with upto 256M
IoTs or private premises.
2. EzIP Overview
2.1. EzIP Numbering Plan
EzIP uses the reserved private network address pools in very much the
same way that Private Automatic Branch eXchange (PABX) switching
machines utilize 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 correlation may seem odd, because the PABX
extension numbers belong to a reusable private set separate from that
of the public telephone numbers and both are independently
expandable, while private network IP address is a specific subset
parsed from the overall IPv4 pool that is otherwise all public and
finite. However, the fact that neither of the latter two is allowed
to operate in the other's domain, the same as in the telephony
practice, suggests that the proposed EzIP numbering plan indeed may
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mirror the PABX. For example, extension 123 or 1234 may exist in
thousands of different PABX switches without ambiguity. Similarly,
the IPv4 private network address blocks (10/8, 172.16/12 and
192.168/16) may also be re-used in many networks without ambiguity.
The key EzIP concept is the partitioning of a finite public address
pool to put aside a block of special (called "Semi-Public" in the
presentation below) addresses that extends each remaining public
address to multitudes of sub-addresses, resulting in an effectively
much larger assignable public address resource.
In fact, the initial EzIP analysis identified the untold two-stage
subnetting process of 192.168/16 that has been practiced routinely
for a long time. End-users are commonly accustomed to an RG choosing
one out of 256 values from the fourth octet of the 192.168.K/24
address block for identifying an IoT on a private premises. They
mostly are, however, unaware of the preceeding stage of selecting the
value "K" from the third octet of the 192.168/16 block, as the
factory default RG identification assigned by a manufacturer, is
implicitly capable of expanding it by 256 fold for supporting a
corresponding number of private premises. A key EzIP concept is to
use the elusive IPv4 240/4 netblock (240/8 - 255/8), that has been
"RESERVED" for "Future use" since 1981-09, as the result of the
historical address assignment evolution. It was proposed to be
redesignated to "Private Use" over a decade ago [2]. However, as
pointed out by its own authors in Section 2, Caveats of Use, "Many
implementations of the TCP/IP protocol stack have the 240.0.0.0/4
address block marked as experimental, and prevent the host from
forwarding IP packets with addresses drawn from this address block."
That proposal did not get advanced. Consequently, to this date, the
240/4 netblock remains practically unused.
Substituting the function of the third octet of 192.168.K/24 with
addresses from the 240/4 netblock in the first stage RG and
redefining it as a new category of router, called SPR, the EzIP
scheme circumvents the earlier hurdles to achieve the address
multiplication factor of 256M without involving any existing router.
This is because the 240/4 addresses are only used by the SPR and
within the Option word header extension. They are not recognized as
IPv4 addresses anywhere within the current Internet, while the Option
word mechanism can carry them through the network as part of the IP
header payload.
Since the 240/4 netblock cannot be used by existing routers, the size
of the maximum assignable IPv4 pool has actually been only 3.84B
(4.096B - 256M). So, the overall assignable pool resulted from the
EzIP approach is about 983MB (3.84B x 256M), which is over 19M times
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of the expected Year 2020 IoTs. This size certainly has the potential
to support the short- to mid-term public IP address needs.
2.2. Analogy with NAT
NAT generally works by temporarily assigning a port number to
outgoing communications originated from a local / private address, by
converting it into a public IPv4 address shared with other local IoTs
for external transmission. When responses are received, the port
number is converted back into the local / private IPv4 address.
EzIP possesses similarities to CG-NAT, but also has some important
differences.
There are a number of limitations of NAT that are not present with
EzIP. (1) There are only 65,536 port numbers but 256M 240/4 EzIP
addresses; (2) Due to the limited number of ports, assignments are
only temporary and will be reclaimed after a period of inactivity,
but there are so many EzIP addresses that assignments will be made
permanent; (3) Port numbers are used for other purposes than NAT,
further reducing the pool, but EzIP uses 240/4 addresses solely for
one purpose; (4) Due to the limited time during which a port number
is assigned, the NAT port numbers cannot be used for incoming
communications, but the EzIP address assignments will be long term
and can be used for direct communications between EzIP-aware devices.
(5) Intriguingly, while RG-NAT provides rudimental defense agaist
intrusion, the dynamic nature of CG-NAT opens up the Internet
vulnerability to cyber attacks, due to its inherent lack of forensic
traceability. SPR will eventually replace CG-NAT for a more efficient
and robust path.
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2.3. EzIP System Architecture
+------+
Web Server | WS0z |
+--+---+
|69.41.190.145
|
| +-----+
+--+ ER0 |
+--+--+
|
+------+-------+
+-------+ Core Routers +--------+
| | (CR/Internet)| |
+--+--+ +--------------+ +--+--+
+-----+ ER1 | +-----+ ER4 |
| +-----+ | +-----+
| |
|69.41.190.110 |69.41.190.148
240.0.0.0 +--+--+ +--+--+
+-----------+ +-------+ +---------+ +------+
| +-----+ SPR1| | | +-----+ SPR4+--+ |
| | +-----+ | |...| +-----+ |...|
| 240.0.0.1 ... 255.255.255.255 | | +---------+ |
+-----+ | | | |
Public | 240.0.0.0 | | 255.255.255.255
Demarc. ----+-------------------------------+----+-------------------
Private |Premises 1 +----------+ |
+--+--+ | Premises 4 |
+---+ RG1 +--+ | |
| +-----+ | | |
| | | |
|192.168.1.3 |192.168.1.9 |240.0.0.10 |246.1.6.40
+--+--+ +--+--+ +--+--+ +--+--+
| T1a | .... | T1z | | T4a | ....... | T4z |
+-----+ +-----+ +-----+ +-----+
Figure 1 EzIP System Architecture
The new category of router, SPR is to be positoned inline between an
ER and the customer premises that it serves. After the original path
is re-established, the remaining addresses in the 240/4 netblock will
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be used by the SPR to serve additional premises. Figure 1 shows a
general view of the enhanced Internet system architecture with two
SPRs, SPR1 and SPR4, deployed. Note that the "69.41.190.x" are static
addresses. In particular, the "69.41.190.145" is the permanent public
Internet address assigned to Avinta.com.
2.3.1. Referring to the lefthand portion labeled "Premises 1" of
Figure 1, instead of assigning each premises a public IPv4 address as
in the current practice, an SPR like SPR1, is inserted between an ER
(ER1) and its connections to private network Routing Gateways like
RG1, for utilizing 240.0.0.0 through 255.255.255.255 of the 240/4
netblock to identify respective premises. The RG1, serving either a
business LAN (Local Area Network) or a residential HAN (Home Area
Network), uses addresses from one of the three private network
[RFC1918] [8] blocks, 10/8, 172.16/12 and 192.168/16, such as
192.168.1.3 and 192.168.1.9 to identify the IoTs, T1a and T1z,
respectively.
2.3.2. Part of the righthand portion of Figure 1 is labeled
"Premises 4". Here SPR4 directly assigns addresses 240.0.0.10 and
246.1.6.40 from the 240/4 netblock to T4a and T4z, respectively.
Consequently, these IoTs are accessible through SPR4 from any other
IoT in the Internet.
2.3.3. Since the existing physical connections to subscriber's
premises terminate at the ER, it would be natural to have SPRs
collocated with their ER for streamlining the interconnections. 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 (Demarc.) line will remain at the RG where currently all
utility services enter a subscriber's premises.
2.3.4. To fully tag each of these devices, we may use a
concatenated three-part address notation: "Public - Semi-Public: TCP
Port". The following is how each of the IoTs in Figure 1 may be
uniquely identified in the Internet.
RG1: 69.41.190.110-240.0.0.0
T1a: 69.41.190.110-240.0.0.0:3
T1z: 69.41.190.110-240.0.0.0:9
T4a: 69.41.190.148-240.0.0.10
T4z: 69.41.190.148-246.1.6.40
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Note that to simplify the presentation, it is assumed at this
juncture that the conventional TCP (Transmission Control Protocol)
[RFC793] [9] Port Number, normally assigned to T1a and T1z by RG1's
RG-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) [RFC2123] [10] subsystem as
":3" and ":9", respectively. Such numbers are unique within each
respective /24 private network such as the 192.168.1/24 here. They
are adequate for the discussion purpose in this document. However,
considering security, as well as allowing each IoT to have multiple
simultaneous sessions, etc., this direct and singular correlation
shall be avoided in actual practice by following the RG-NAT operation
conventions as depicted by the examples in Appendix A.
Figure 2 groups IoTs, routers and servers into two separate columns,
EzIP-unaware or EzIP-capable, to facilitate discussions that are to
follow.
+--------------------------+-----------------+----------------+
| | EzIP-unaware | EzIP-capable |
+--------------------------+-----------------+----------------+
| Internet Core Router (CR)| CR | ------------ |
+--------------------------+-----------------+----------------+
| 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 2 EzIP System Components
2.4. IP Header with Option Word
To transport the EzIP Extension Addresses through existing devices
without being recognized as such and consequently acted upon, the IP
Header Option mechanism defined by Figure 9 in Appendix A of [RFC791]
is utilized to carry it as the payload. One specific aspect of its
format deserves some attention. The meanings of the leading eight
bits of each Option word, called "Opt. Code" or "Option-type octet",
are summarized on Page 15 of [RFC791]. They are somewhat confusing
because the multiple names used in the literature, and how the octet
is parsed into functional bit groups. For example, a two digit
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hexadecimal number, "0x9A", is conventionaly written in the binary
bit string form as "1001 1010". As Opt. Code, however, the eight bits
here are parsed into three groups of 1, 2 and 5 bits as "1 00 11010"
with meanings described in Figure 3.
+--------------------------------------------------------------+
| Meaning of EzIP ID = 0x9A (Example) |
+--------------+------------------+----------------------------+
| Copy Bit | Class | Option Value / Number |
+--------------+------------------+----------------------------+
| 1 (Set) | 00 (Control) | 11010 (26 - base 10) |
+--------------+------------------+----------------------------+
Figure 3 Option Type Octet
A value of "1" for the first bit instructs all routers that this
Option word is to be copied upon packet fragmentation. This preserves
the Option word through such a process, if it is performed.
The value of "00" for the next two bits indicates that this Option
word is for "Control" purpose.
The decimal "Option Value" of the last five bits, equaling to "26" is
defined as the "Option Number" that is listed in the "Number" column
of the Internet Protocol Version 4 (IPv4) Parameters list [11]. As
can be seen there, "26" has not been assigned. Thus, it is
temporarily used in this document to facilitate the EzIP
presentation. The next unassigned Option Code, "0x9B" or Number "27"
will also be tentatively utilized in this document.
2.5. Examples of Option Mechanism
The Option mechanism has been used for various cases. Since they were
mostly for utility or experimental purposes, however, their formats
may be remote from the incident topic. There were two cases
specifically dealt with the address pool issues. They are referenced
here to assist the appreciation of the Option mechanism.
A. EIP (Extended Internet Protocol) - Figure 1 of [RFC1385] [12]
(Assigned but now deprecated Option Number = 17) by Z. Wang: This
approach proposed 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, those among the CRs
apparently had to go through rather extensive upgrading procedures,
perhaps due to the flexible length of the extended address (could be
much longer than that of the IPv6).
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B. EnIP (Enhanced IPv4) - Figure 1 of Internet Draft [13]
(temporarily utilizing Option Number = 26) by W. Chimiak: This work
made use of the three existing private network blocks to extend the
public pool by trading the private network operation for end-to-end
connectivity. The fully deployed EnIP will eliminate the current
private networks which may be against the intuitive preference of
end-users who have found the private network configuration quite
desirable. For example, the RG-NAT serves as a rudimentary deterrent
against intrusion. In addition, the coexistence of private RG-NAT and
public EnIP router functions in the same EnIP devices (N1 & N2),
could lead to certain logistic inconsistency concerns.
2.6. EzIP 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 (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 | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 | No.-2 | No.-3 | No.-4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 Full EzIP Header
The proposed EzIP header format shown in Figure 4 can transport the
full 4 octet (32 bit) extension addresses of both ends of an Internet
link. The extension address in the 240/4 netblock utilized in the
EzIP scheme described herein has 28 significant bits. It is possible
for EzIP to use addresses having other lengths of significant bits
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for different multiplication factors. To prepare for such variations,
two separate EzIP ID codes, "0x9A" and "0x9B" are proposed to
distinguish between Source and Destination Option words,
respectively, as basic examples.
2.7. EzIP Operation
To convey the general scheme, Appendix A presents examples of IP
header transitions through routers, between IoTs with or 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, an
SPR must be able to follow certain decision branches to determine how
to provide the appropriate routing service for a smooth transition to
the long term operation. Appendix B outlines such logic and related
considerations.
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 should be dealt with first to
immediately mitigate the address shortage induced daily issues. In
the process, the latter would be built up naturally.
A. Architecturally
Since the design philosophy of the SPR is an inline module between an
ER and the private premises (RG or directly connected IoTs) that it
serves, SPR introduction process can be flexible.
A.1. An SPR may be deployed as an inline module right after an ER
to begin providing the CG-NAT equivalent function. This could be done
immediately without affecting any of the existing Internet
components, CR, ER and RG. EzIP-capable IoTs will then take advantage
of the faster bi-directional routing service through the SPRs by
initiating communication sessions utilizing EzIP headers to contact
other EzIP-capable IoTs.
A.2. Alternatively, an SPR may be deployed as an adjunct module
just before an existing RG or a directly connected IoT to realize the
same EzIP functions on the private premises, even if the serving
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Internet Access Provider (IAP) has not enhanced its ERs with the EzIP
capability.
This approach will empower individual communities to enjoy the new
EzIP capability on their own by upgrading all Internet subscribers
within a good sized region to have publicly accessible EzIP addresses
for intra-community peer-to-peer communication, starting from just
using one existing public IPv4 address to identify the entire region
through a gateway to the rest of the world. See sub-section C. below
for more specific considerations.
B. Functionally
B.1. First, an IAP 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 if businesses on their own deploy
new web servers with the SPR capability built-in.
B.2. On the subscriber side, SPRs should be deployed to
disseminate static addresses to the public, and to facilitate the
access to new web servers.
C. Regional Area Network
C.1. Since the size of the 240/4 netblock is significant, a
region mentioned in sub-section A.2. above could actually be fairly
large. Based on the assumption that each person, on the average, may
have 6.6 IoTs by Year 2020 [3], a 240/4 netblock is capable of
serving nearly 39M (256M / 6.6) individual devices, even before
utilizing any private netblocks to manage private prmises. This
exceeds the population of the largest city on earth (38M - Tokyo
Metro.) and 75% of the countries around the world (i. e., most of the
233 countries other than the top 35). Therefore, any finite sized
region can immediately begin to enjoy EzIP addressing by deploying a
Regional Area Network (RAN) utilizing SPRs operating with one 240/4
netblock of addresses from one IPv4 public address. With the gateway
for a region configured in such a way that the entire region appears
to be one ordinary IPv4 IoT to the rest of the Internet, a self-
contained RAN may be deployed anywhere there is the need or desire,
with no perturbation to the current Internet operations whatsoever.
C.2. This gateway may be constructed with a matured networking
technology called Caching Proxy [14], popularized by data-intensive
web services such as Google, Amazon, Yahoo, as well as gateways for
corporate LANs, VPN (Virtual Private Network), etc. Developed for
speeding up response to repetitive queries from a group of
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subscribers on the same topic, while storing data from the central
data bank, caching proxies are placed at strategic locations close to
potential high activities, essentially cloning the central data bank
into distributed copies (not necessarily a full set, but containing
all relevant subsets pertaining to the local community). This
architecture meshs with the EzIP-based RAN very well, because the
address translation between the IPv4 in the Internet and the EzIP in
the RAN can be accomplished transparently through the two ports of a
caching proxy (For such matter, even could be between the IPv6 and
the EzIP if desired!). Consequently, existing Internet routers, such
as CR and ER may not see any IP packet with EzIP header at all,
during the initial phase of the RAN deployment which will primarily
consist of basic intra-regional messaging and web service access in a
primarily local operation mode. Ongoing study of this possibility is
reported in Appendix F.
C.3. This configuration actually mimicks the PABX environment
almost exactly. Since the entire region is only accessible through
the gateway that performs the address translation, degenerated EzIP
header (conventional IP header with words 4 and 5 using 240/4
netblock addresses) will be suffice for the intra RAN traffic. This
mirrors the dialing procedure of using only extension numbers among
stations served by the same PABX, circumventing the unnecessary and
wasteful overhead of including the dialing of the common public
telephone number prefix whose only purpose is to identify the PABX to
the PSTN which is not involved in such intra-PABX communications.
C.4. The full EzIP header format will only be used when an EzIP-
capable IoT intends to directly interact with an EzIP-capable IoT in
another RAN. The last part is equivalent to the IDDD (International
Direct Distance Dialing) conventions when a call is made through the
PSTN to a station outside of a PABX.
C.5. The RAN would streamline the CIR (Country-based Internet
Registry) model proposed by ITU-T [18] as well. Instead of allocating
a block of public IPv6 addresses to an ITU-T authorized entity
(essentially the sixth RIR - Regional Internet Registry) to
administrate on behalf of individual countries, the EzIP RAN
configuration enables each member state to start her own CIR with up
to 256M IoTs, based on just one of the IPv4 public address already
allocated to that country from the responsible RIR. Consequently,
each CIR is coordinated by its parent RIR, yet its operation can
conform to local preferences. This configuration will establish a
second Internet service parallel to the existing one for
demonstrating their respective merits independently, offering
subscribers true options to choose from.
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D. Permanently
In the long run, it would be best if SPRs are integrated into their
host ER by upgrading the latter's firmware to minimize the hardware
and to streamline the equipment interconnections.
Appendix B 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 [RFC791] [1],
it has not been used much in daily traffic. Compatibility with
current Internet facilities and conventions may need be reviewed.
Since the EzIP data is transported as part of the IP header payload,
it is not expected to affect higher layer protocols. However, certain
facilities may have been 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 that 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 [15]. This puts EzIP
packets at a disadvantage, because EzIP packets will have to go
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
address pool exhaustion affecting web server access, subscribers not
demanding high throughput performance may be migrated to the EzIP
supported facility first. This gives CRs the time to update so that
EzIP packets with authorized Option numbers will eventually be
recognized for receiving the "fast-path" service. On the other hand,
an alternative logic may be applied for the CR. That is, it should by
default ignore any Option word in an IP header so that all IP packets
will be processed through the "fast-path", unless a recognizable
Option word requiring action is detected. This approach would
mitigate the security issues caused by the "source routing" attack,
as well.
B. Connectivity Verification
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One frequently used probing 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
64 bits long instead of the current 32 bit IPv4 address. There is an
example of an upgraded TCP echo server in [RFC862] [16].
C. Domain Name Server (DNS)
Similarly, the DNS needs to expand its data format to transport the
longer IP address created by the EzIP. This already can be done under
IPv6. Utilizing the experimental IPv6 prefix 2001:0101 defined by
[RFC2928] [17], EzIP addresses may be transported as standardized
AAAA records.
These topics are discussed in more detail under an IETF Draft RFC,
Enhanced IPv4 - V.03 [13].
5. EzIP Enhancement and Application
To avoid disturbing any assigned address, deployed equipment and
current operation, etc., the EzIP scheme is derived under the
constraint of utilizing only the reserved 240/4 address block. If
such restriction were removed by allowing the entire IPv4 address
pool be flexibly re-allocatable, the assignable public address pool
could be expanded significantly more, as outlined below.
A. If the 240/4 netblock were doubled to 224/3, each existing IPv4
public address would be expanded by 512M fold. Since this block of
512M addresses have to be first reserved from the basic public pool,
the resultant total addresses will be (4.096B - 512M) x 512M, or
1,835MB. This is over 36M times of the predicted number of IoTs (50B)
by Year 2020. This calculation leads to additional possibilities.
B. The EzIP header in Figure 4, capable of transporting the full 32
bit IPv4 address, allows the extension number to be as long as
practical. That is, we can go to the extreme of reserving only one
bit for the network number, and using all the rest of bits for the
extension address. With this criterion, the basic IPv4 pool may be
divided into two halves, reserving one half of it (about 2B
addresses) as a semi-public network with the network number prefix
equal to "1". Each of the remaining 2B public addresses (with prefix
equal to "0") of the basic IPv4 pool may then be extended 2B fold
through the EzIP process, resulting in a 4BB address pool. This is
roughly 80M times of the Year 2020 IoT needs.
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C. If the EzIP technique were applied through several layers of SPRs
in succession, the address expansion could be even more. For example,
let's divide the IPv4 pool equally into four blocks, each with about
1B addresses. Apply the first 1B address block to the public routers.
Set up three layers of SPRs, each makes use of one of the remaining
three 1B address blocks. The resultant assignable pool will have
1BBBB addresses. Under this configuration, the full length of an
IoT's identification code will be the concatenation of four segments
of 32 bit IPv4 address, totalling 128 bits, the same as that of the
IPv6. The first two bits of each segment, however, being used to
distinguish from the other three address blocks, are not significant
bits. This 8-bits difference makes the IPv6 pool 256 times larger.
This ratio is immaterial, because even the 1BBBB address pool is
alreaby 20MBB times of the foreseeable need. It is the hierarchical
addressing characteristics, made possible by the EzIP scheme, that
will enhance the Internet, such as truncating out the common address
prefix for communicating within a local community, and associating an
address with the geographical position, thus mitigating the
GeoLocation related issues.
D. Along this line of reasoning, we could combine two 1B address
blocks togther to be the basic public address. The overall assignable
pool becomes 2BBB which is still 40MB times of the expected IoT
need(50B). With this pool, we can divide the entire globe into 2B
regions, each served by one public router. Each region can then be
divided into 1B sections, identified by the first group of SPRs.
Next, each section will have the second group of SPRs to manage upto
1B RGs and IoTs. Since the basic 2B public addresses are already more
than half of the current total assignable IPv4 public addresses
(3.84B), their potential GeoLocation resolution capabilities are
comparable. With additional two layers of SPR routing, 1B for each,
the address grid granuality will be so refined that locating the
source of an IP packet becomes a finite task, leaving perpetrators
little room to hide.
E. The following outlines a possible procedure for optimizing the use
of the EzIP address resource by transforming the current Internet to
be a GeoLocation-capable address system while maintaining the
existing IPv4 addressing and operation conventions:
a. Quantitative Reference: IETF [RFC6598] [6] reserved the
100.64/10 block with 4M addresses for supporting IAP's CG-NAT
service. Applying all of these to the entire IPv4 pool of 4B
addresses, the maximum effective CG-NAT supported IPv4 address pool
could be 16MB. This is 0.32M times of the expected number (50B) of
IoTs by Year 2020.
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b. Employing the 240/4 netblock with 256M addresses in the EzIP
extension scheme, a /6 block with 64M addresses from the IPv4 basic
public pool is sufficient to replicate the above 16MB capacity. This
frees up the majority of the IPv4 public pool.
c. Since this will be a temporary holding pool to release the
current addresses for new assignments, it should occupy as few public
addresses as possible to leave the maximum number of addresses for
facilitating the long term planning. To just support the expected 50B
IoTs need, only 200 IPv4 public addresses are required (200 x 256M =
50B). Thus, a /24 block with 256 addresses is more than enough to
accommodate this entire migration process. This frees up even more
IPv4 public addresses.
d. Although a single /24 public address block is sufficient for
migrating all currently perceived IPv4 address needs into one compact
temporary EzIP pool, world-wide coordination of new address
assignments and routing table updates will be required. It will be
more expeditious to carry out this preparatory phase on an individual
country or geographical region basis utilizing public IPv4 addresses
already assigned to that area and actively served by existing CR
routing tables. Since 200 public addresses are enough to port the
entire IoT addresses, most of the 233 countries other than the top 35
(about 75%) countries should be able to port all of their respective
predicted IoTs to be under one 240/4 netblock, each represented by
one gateway to the Internet. If this is managed according to
geographical disciplines, each participating region will begin to
enjoy the benefits of the EzIP approach, such as plentiful assignable
public addresses, robust security due to inherent GeoLocation ability
to spot hackers from within, so that efforts may be focused on only
screening suspicious packets originated from without.
e. As IoTs are getting migrated to the temporary pool, the IPv4
addresses they originally occupy shall be released to re-populate the
public address pool for establishing full scale EzIP operation.
f. Upon the completion of the EzIP based world-wide public address
allocation map, each country can simply give up the few temporary
public addresses in exchange for the permanent assignments. Since the
latter is likely more than the former, addresses in one 240/4
netblock will be served by two (or more) 240/4 netblocks. Then, each
of such 240/4 netblock will have more than half of its capacity
available to serve the growth of additional IoTs.
g. This last step is very much the same as the traditional PSTN
"Area Code Split" practice, whereby telephone numbers of a service
area are split into two (or more) blocks, upon introducing one (or
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more) new area code(s) into the area. All subscribers will continue
to use their original local telephone numbers for calling among
neighbors daily, except some may be assigned with a new area code
prefix. Upon the split, each area code will have more than half of
its assignable telephone numbers availabe to support the future
subscriber growth within its service area. Mimicking the PSTN, the
EzIP based Internet will have similar GeoLocation capability as the
former's caller identification based services, such as the 911
emergency caller location system in US, mitigating the root cause to
the cybersecurity vulnerability.
F. With the IPv4 address shortage issue resolved, potential system
configurations utilizing the EzIP enhanced address pool may be
explored.
a. Although the entire predicted number (50B) of IoTs by Year 2020
may be served by just one /24 IPv4 public address block utilizing the
EzIP scheme with a 240/4 netblock, let's replace it with a /8 block
(16M addresses), resulting in about 4MB (16M x 256M) assignable
addresses. This is 80K times of the expected 50B IoTs. Or, each and
every person (of predicted 2020 population) would have to own over
500K IoTs to use up this address pool. It is apparent that the spares
in this allocation should be sufficient to support the growth of the
IoTs for some years to come.
b. Next, the IPv4 pool originally has 256 blocks of /8 addresses.
After the above allocation, there are still 239 blocks of /8
addresses available to support additional digital communication
systems, each having the same size of address pool as the allocation
above. Consequently, many world-wide communication networks may
coexist under the same IPv4 protocol framework in the form of groups
of RANs as described earlier, with arm's-length links among them.
c. For example, a satellite based Internet that is being proposed
[19], such as StarLink can start fresh as one EzIP RAN served by one
SPR having the capacity of 256M IoTs, under one ER capable of
managing one /8 block of IPv4 public address. Utilizing a caching
proxy as the gateway to handle the data exchange with other RAN, this
satellite based Internet with 256M hosts can operate pretty much as
an isolated system by using 240/4 addresses in the basic IP headers
for intra-RAN communications, most of the time. Only when direct
communication with another RAN (such as the one for the existing
Internet) is needed, will the full EzIP header be required. As users
grow, additional RANs (each with 256M IoTs capacity), may be
incrementally added to support the expansion.
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G. In summary, utilizing the 240/4 netblock, the EzIP scheme may
expand the IPv4 based Internet to be a collection of up to 240 groups
of 16M RANs each managed by one SPR with 256M IoTs capacity that are
inter-operable digital communication systems, normally operate at
arm's-lenghth to one another. Each of these groups has the address
capacity of at least 80K times of the number of predicted (50B) IoTs
by Year 2020.
6. Security Considerations
The EzIP solution is based on an inline module called SPR that is
intended to be as transparent to Internet traffic as possible. The
proposed address assignment rule is deterministic and systematic.
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
To resolve the IPv4 public address pool exhaustion issue, a technique
called EzIP (phonetic for Easy IPv4) making use of a long reserved
address block 240/4, is proposed.
This draft RFC describes an enhancement to IPv4 operation utilizing
the IP header Option mechanism defined in [RFC791]. Since 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.
The basic EzIP philosophy includes maintaining the existing public
and private network structure. Upon reclassifying the "RESERVED for
Future use" 240/4 netblock to be the Semi-Public address pool, it
will only be usable by the new SPR (Semi-Public Router) as the EzIP
extension address. This pool can multiply each current IPv4 public
address by 256M fold, while all existing public network and
subscriber premises setups (private networks as well as directly
connected IoTs) may remain unchanged. A subscriber is encouraged to
upgrade his IoT(s) to be EzIP-capable so as to fully enjoy the
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enhanced router service by EzIP for end-to-end communication. This
particular manifestation of the EzIP scheme appears to be the optimal
solution to our needs.
The 240/4 netblock based EzIP scheme will not only relieve the IPv4
address shortage, but also improve the defense against cybersecurity
intrusion by virtue of systematic and deterministic address
management. The EzIP RAN (Regional Area Network) configuration will
also support the desire to establish CIR (Country-based Internet
Registry) operation expressed by ITU-T, as a parallel local facility
providing services equivalent to the current global Internet.
Furthermore, EzIP will help the IPv4 based Internet to become the
common backbone for multiple world-wide digital communication systems
such as satellite based systems like StarLink that normally would
operate in arm's-length from one another.
These last two possible applications turn out to be a generic
architectural feature that is also suitable for establishing test
beds at arm's-length to one another for developing new protocols and
products. This particular manifestation of the EzIP empowers end-
users to participate in the evaluation, and the smooth transition
from testing to the eventual use, of new services in a realistic, not
simulated, parallel environment.
9. References
9.1. Normative References
[1] https://tools.ietf.org/html/rfc791
[2] https://tools.ietf.org/html/draft-wilson-class-e-02
9.2. Informative References
[3] https://www.cisco.com/c/dam/en_us/about/ac79/docs/innov/IoT_IBS
G_0411FINAL.pdf
[4] http://stats.labs.apnic.net/ipv6
[5] https://stats.ams-ix.net/sflow/ether_type.html
[6] https://tools.ietf.org/html/rfc6598
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[7] http://www.iana.org/assignments/ipv4-address-space/ipv4-
address-space.xhtml
[8] https://tools.ietf.org/html/rfc1918
[9] https://tools.ietf.org/html/rfc793
[10] https://www.ietf.org/rfc/rfc2131.txt
[11] http://www.iana.org/assignments/ip-parameters/ip-
parameters.xhtml
[12] https://tools.ietf.org/html/rfc1385
[13] https://tools.ietf.org/html/draft-chimiak-enhanced-ipv4-03
[14] https://en.wikipedia.org/wiki/Proxy_server#Improving_performanc
e
[15] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.477.19
42&rep=rep1&type=pdf
[16] https://tools.ietf.org/html/rfc862
[17] https://tools.ietf.org/html/rfc2928
[18] https://www.nro.net/wp-content/uploads/nro-response-to-ls-5.pdf
[19] https://www.commerce.senate.gov/public/index.cfm/2017/10/the-
commercial-satellite-industry-what-s-up-and-what-s-on-the-
horizon
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 their EnIP development.
This document was prepared using 2-Word-v2.0.template.dot.
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Appendix A EzIP Operation
To demonstrate how EzIP could support and enhance the Internet
operations, the following are three sets of examples that involve
SPRs as shown in Figure 1. These present a general perspective of how
IP header transitions through the routers may look like.
1. The first example is between EzIP-unaware IoTs, T1a and T4a. This
operation is very much the same as the conventional TCP/IP packet
transmission except with SPRs acting as an extra pair of routers
providing the CG-NAT service.
2. The second one is between EzIP-capable IoTs, T1z and T4z. Here,
the SPRs process the extended semi-public IP addresses in router
mode, avoiding the drawbacks due to the CG-NAT type of table look-up
operations above.
3. The last one is between EzIP-unaware and EzIP-capable IoTs. By
initiating and responding with a conventional IP header, EzIP-capable
IoTs behave like EzIP-unaware IoTs. Thus, all packet exchanges use
the conventional IP headers, just like case 1. above.
A.1. Connection between EzIP-unaware IoTs
A.1.1. T1a Initiates a Session Request towards T4a
T1a sends a session request to SPR4 that serves T4a by a plain IP
packet with header as in Figure 5, 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 5 IP Header: From T1a to RG1
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A.1.2. RG1 Forwards the Packet to SPR1
RG1, allowing be masqueraded by T1a, relays the packet toward SPR1
by assigning the TCP Source port number, 3N, to T1a, with a header as
in Figure 6,. Note that the suffix "N" denotes the actual TCP port
number assigned by the RG1's RG-NAT. This could assume multiple
values, each represents a separate communications session that T1a is
engaged in. A corresponding entry is created in the RG1 state table
for handling the reply 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 (240.0.0.0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5 | Destination Host Number (69.41.190.148) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6 | Source Port (3N) | Destination Port (All 1's) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6 TCP/IP Header: From RG1 to SPR1
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A.1.3. SPR1 Sends the Packet to SPR4 through the Internet
SPR1, detecting no EzIP Option word, acts like a CG-NAT. It allows
being masqueraded by RG1 (with the Source Host Number changed to be
SPR1's own and the TCP port number changed to 0C, where "0" is the
last octet of RG1's IP address, and "C" stands for CG-NAT) and sends
the packet as in Figure 7 out through the Internet towards SPR4. The
packet traverses through the Internet (ER1, CR and ER4) utilizing
only the Destination Host Number (word 5) in the 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 (69.41.190.110) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5 | Destination Host Number (69.41.190.148) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6 | Source Port (0C) | Destination Port (All 1's) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7 TCP/IP Header: From SPR1 to SPR4
Note that although schematically shown in Figure 1 as one public IPv4
address serving one SPR capable of a full 240/4 address block, the
PCP port number has a theoretical limit of 64K (256 x 256) because it
consists of 16 bits. This is much smaller than a full 240/4 pool.
Even with dynamic assignments, it will take quite a few public
address to serve the CG-NAT need if many IoTs are EzIP-unaware. So,
IoTs are encouraged to become EzIP-capable as soon as possible to
avoid straining the SPR's CG-NAT capability. This should not be an
issue for emerging regions currently having very little facility and
IoTs. As new ones are deployed, they should be enabled as EzIP-
capable by factory default. For the rural area of developed countries
with existing EzIP-unaware IoTs, the need for CG-NAT service will be
greater. Multiple IPv4 public addresses would be needed initially to
support smaller sub- 240/4 netblocks. This is probably workable
because the latter does have more public IPv4 addresses. The CG-NAT
techniques developed under [RFC6598] [6] may be incorporated here to
facilitate the transition.
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A.1.4. SPR4 Sends the Packet to T4a
Since the packet has a conventional TCP/IP header without Destination
TCP port number, SPR4 would ordinarily drop it due to the CG-NAT
function. However, for this example, let's assume that there exists a
state-table that was set up by a DMZ (De-Militaried Zone) process for
redirecting this packet to T4a with a CG-NAT TCP port number 10C
(Here, "10" is the fourth octet of T4a's Extension address, and "C"
stands for CG-NAT.). After constructing the Destination Host Number
accordingly, SPR4 sends the packet to T4a with a header as in Figure
8.
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 (240.0.0.10) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6 | Source Port (0C) | Destination Port (10C) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8 TCP/IP Header: From SPR4 to T4a
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A.1.5. T4a Replies to SPR4
T4a interchanges the Source and Destination identifications in the
incoming TCP/IP packet to create a header as in Figure 9, for the
reply packet to SPR4.
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 (240.0.0.10) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5 | Destination Host Number (69.41.190.110) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6 | Source Port (10C) | Destination Port (0C) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9 TCP/IP Header: From T4a to SPR4
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A.1.6. SPR4 Sends the Packet to SPR1 through the Internet
SPR4, allowing being masqueraded by T4a, sends the packet toward SPR1
with the header in Figure 10, 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 (10C) | Destination Port (0C) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10 TCP/IP Header: From SPR4 to SPR1
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A.1.7. SPR1 Sends the Packet to RG1
Using the stored data in the CG-NAT state-table, SPR1 reconstructes a
header as in Figure 11, for sending the packet to RG1.
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 (240.0.0.0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6 | Source Port (10C) | Destination Port (3N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11 TCP/IP Header: From SPR1 to RG1
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A.1.8. RG1 Forwards the Packet to T1a
From the state-table in RG1's RG-NAT, T1a address is reconstructed
based on Destination Port (3N), as in Figure 12.
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 (10C) | Destination Port (3N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12 TCP/IP Header: From RG1 to T1a
A.1.9. T1a Sends a Follow-up Packet to RG1
To carry on the communication, T1a constructs a full TCP/IP header as
in Figure 13 for sending the follow-up packet to RG1.
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 (10C) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13 TCP/IP Header: Follow-up Packets From T1a to RG1
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A.2. Connection Between EzIP-capable IoTs
The following is an example of EzIP operation between T1z and T4z
shown in Figure 1, with full "Public - EzIP : Private" network
addresses, "69.41.190.110-240.0.0.0:9" and "69.41.190.148-
246.1.6.40", respectively. Note that T4z, without the private portion
(TCP port number) in the concatenated address, is directly
addressable from the Internet. For T1z to initiate a session, it
needs to know the full address of T4z, but only it's own private
address.
A.2.1. T1z Initiates a Session Request towards T4z
T1z sends an EzIP packet, as in Figure 14, to RG1. There is no TCP
port number word, because T4z does not have such while that for T1z
is waiting for assignment from the RG1's RG-NAT. Also, the Extended
Source No. is filled with all "1's", waiting for being specified by
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 (8)|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 | Extended |
6 | (Source) | Option Length | Source | Source |
| (0X9A) | (6) | No.-1 (255) | No.-2 (255) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (255) | No.-4 (255) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (246) | No.-2 (1) | No.-3 (6) | No.-4 (40) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 14 EzIP Header: From T1z to RG1
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A.2.2. RG1 Forwards the Packet to SPR1
RG1, allowing to be masqueraded by T1z, relays a packet as in
Figure 15, toward SPR1 by assigning the TCP Source port number, 9N,
to T1z. Not knowing whether T4z is behind an RG, "All 1's" is used to
fill the Destination Port part 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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2 | Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3 | Time to Live | Protocol | Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4 | Source Host Number (240.0.0.0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5 | Destination Host Number (69.41.190.148) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EzIP ID | EzIP | Extended | Extended |
6 | (Source) | Option Length | Source | Source |
| (0X9A) | (6) | No.-1 (255) | No.-2 (255) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (255) | No.-4 (255) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (246) | No.-2 (1) | No.-3 (6) | No.-4 (40) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (9N) | Destination Port (All 1's) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 15 TCP/EzIP Header: From RG1 to SPR1
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A.2.3. SPR1 Sends the Packet to SPR4 through the Internet
SPR1 replaces the Source Host Number with its own as well as fills in
the Extended Source No. information, and then sends the packet, with
a header as in Figure 166, out into the Internet towards SPR4. The
packet traverses through ER1, CR and ER4, utilizing only the
Destination Host Number (Word 5) in the 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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 | Extended |
6 | (Source) | Option Length | Source | Source |
| (0X9A) | (6) | No.-1 (240) | No.-2 (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (0) | No.-4 (0) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (246) | No.-2 (1) | No.-3 (6) | No.-4 (40) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (9N) | Destination Port (All 1's) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 16 TCP/EzIP Header: From SPR1 to SPR4
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A.2.4. SPR4 Sends the Packet to T4z
SPR4 reconstructs T4z address from the Option number 0X9B and the
Extended Destination No. then sends the packet, with the header as in
Figure 17, to 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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2 | Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3 | Time to Live | Protocol | Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4 | Source Host Number (69.41.190.110) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5 | Destination Host Number (246.1.6.40) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EzIP ID | EzIP | Extended | Extended |
6 | (Source) | Option Length | Source | Source |
| (0X9A) | (6) | No.-1 (240) | No.-2 (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (0) | No.-4 (0) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (246) | No.-2 (1) | No.-3 (6) | No.-4 (40) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (9N) | Destination Port (All 1's) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 17 TCP/EzIP Header: From SPR4 to T4z
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A.2.5. T4z Replies to SPR4
Making use of the information in the incoming TCP/EzIP header, T4z
replies to SPR4 with a full header, as in Figure 18.
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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2 | Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3 | Time to Live | Protocol | Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4 | Source Host Number (246.1.6.40) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5 | Destination Host Number (69.41.190.110) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EzIP ID | EzIP | Extended | Extended |
6 | (Source) | Option Length | Source | Source |
| (0X9A) | (6) | No.-1 (246) | No.-2 (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (6) | No.-4 (40) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (240) | No.-2 (0) | No.-3 (0) | No.-4 (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (All 1's) | Destination Port (9N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 18 TCP/EzIP Header: From T4z to SPR4
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A.2.6. SPR4 Sends the Packet to SPR1 through the Internet
SPR4 replaces the Source Host Number with its own, and sends the
packet with the header, as in Figure 19, towards SPR1. The Internet
(ER4, CR, and ER1) simply relays the packet according to the TCP/EzIP
header 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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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) | (6) | No.-1 (246) | No.-2 (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (6) | No.-4 (40) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (240) | No.-2 (0) | No.-3 (0) | No.-4 (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (All 1's) | Destination Port (9N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 19 TCP/EzIP Header: From SPR4 to SPR1
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A.2.7. SPR1 Sends the Packet to RG1
SPR1 reconstructs RG1 address from the Option number 0X9B and the
Extended Destination No. Then, sends packet with a header as in
Figure 20 toward RG1.
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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2 | Identification |Flags| Fragment Offset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3 | Time to Live | Protocol | Header Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4 | Source Host Number (69.41.190.148) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5 | Destination Host Number (240.0.0.0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EzIP ID | EzIP | Extended | Extended |
6 | (Source) | Option Length | Source | Source |
| (0X9A) | (6) | No.-1 (246) | No.-2 (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (6) | No.-4 (40) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (240) | No.-2 (0) | No.-3 (0) | No.-4 (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (All 1's) | Destination Port (9N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 20 TCP/EzIP Header: From SPR1 to RG1
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A.2.8. RG1 Forwards the Packet to T1z
RG1 reconstructs T1z address from RG1's RG-NAT state-table based on
Destination Port (9N), then sends the packet to T1z with a header as
in Figure 21.
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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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) | (6) | No.-1 (246) | No.-2 (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (6) | No.-4 (40) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (240) | No.-2 (0) | No.-3 (0) | No.-4 (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (All 1's) | Destination Port (9N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 21 TCP/EzIP Header: From RG1 to T1z
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A.2.9. T1z Sends a Follow-up Packet to RG1
With all fields filled with needed information from the incoming
TCP/EzIP header, T1z sends a follow-up packet to RG1 as in Figure 22.
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 (9)|Type of Service| Total Length (36) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 | Extended |
6 | (Source) | Option Length | Source | Source |
| (0X9A) | (6) | No.-1 (240) | No.-2 (0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | EzIP ID | EzIP |
7 | Source | Source | (Destination) | Option Length |
| No.-3 (0) | No.-4 (0) | (0X9B) | (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended | Extended | Extended | Extended |
8 | Destination | Destination | Destination | Destination |
| No.-1 (246) | No.-2 (1) | No.-3 (6) | No.-4 (40) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 | Source Port (9N) | Destination Port (All 1's) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 22 TCP/EzIP Header: Follow-up Packets from T1z to RG1
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A.3. Connection Between EzIP-unaware and EzIP-capable IoTs
A.3.1. T1a Initiates a Request to T4z
Since T1a can create only conventional format IP header, the SPRs
will provide CG-NAT type of services to the TCP/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 with conventional TCP/IP header, T4z should respond
with the same so that the session will be conducted with conventional
TCP/IP headers. The interaction will follow the same behavior as in
Appedix A.1.
A.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 as in Appedix
A.1. so that the packet will be recognizable by T4a.
Note that to maximize the combination in the EzIP System Architecture
diagram (Figure 1) for demonstrating the possible variations, there is
no RG on Premises 4. IoTs, such as T4a and T4z, are thus directly
connected to a SPR, like SPR4 and there is no corresponding TCP port
number in word 9 of the above TCP/EzIP headers. This spare facility in
the header suggests that an RG may be installed if desired, to establish
the similar private network environment as that on Premises 1.
In brief, the steps outlined above are very much the same as the
conventional TCP/IP header transitions through the Internet with the SPR
providing the CG-NAT service. Except, when a TCP/EzIP header is
detected, the SPR switches to the router mode for forwarding the packet
to improve the performance.
In essence, with the EzIP system architecture very much the same as
today's Internet, the SPR starts with assuming the current CG-NAT duty,
while ready to perform the new EzIP routing function for EzIP-aware
IoTs. This strategy offers a simple transition path for the Internet to
evolve toward the future.
It is important to note that both SPR and CG-NAT are inline devices with
respect to ER. However, since CG-NAT provides soft / ephemeral TCP
ports, it is positioned between a CR and ERs, while SPR is located
between an ER and RGs to assign hard / static physical addresses.
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Appendix B 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 required modification. The basic EzIP plan is to
confine all actionable enhancements within the new SPR module(s). The
following outlines the considerations for supporting the transition
from the current Internet to the one enhanced by the EzIP technique.
B.1. EzIP Implementation
B.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. This
configuration is commonly referred to as a reverse proxy. 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.,
242.0.0.0, used by the SPR should be reserved as a DMZ channel
directing the initial incoming service requesting packets to the
existing web server. This will maintain the same current operation
behavior projected to the general public.
. The additional addresses, up to 255.255.255.255 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
accessible through its own EzIP address.
B. Insert an SPR in front of a group of subscribers who are to be
served with the EzIP capability. The basic service provided by this
SPR will be the CG-NAT equivalent function. This will maintain the
same current 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 through existing DNS). The server
should respond with the basic IPv4 format as well. Essentially, this
maintains the existing user experience between a customer 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
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today's common practice utilizing CG-NAT assisted connectivity. See
Appendix A.1. for an example.
D. Upon connection to the main web server, if a customer
intentionally selects one of the new services, the main web server
should 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 session via an EzIP
address.
. The SPR on the customer side, recognizing the EzIP header from
the branch web-server, replaces the CG-NAT service with the EzIP
routing.
. For all subsequent packets exchanged, the EzIP headers will be
used in both directions. This will speed up the transmission
throughput performance for the rest of the session. See Appendix A.2.
for an example.
B.1.2. New IoT Operation Modes:
A. EzIP-capable IoT will create EzIP header in initiating a session,
to directly reach a specific EzIP-capable web-server, instead of the
manual interaction steps of going through the DMZ port then making
the selection from the main web server. This will speed up the
initial handshake process. See Appendix A.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 the CG-NAT type of connection
service. See Appendix A.1. for an example.
B.1.3. End-to-End Operation:
Once EzIP-capable IoTs become wide spread among 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 SPRs to provide EzIP service, bypassing the CG-NAT process.
See Appendix A.2. for an example.
B.2. SPR Operation Logic
To support the above scenarios, the SPR should be designed with the
following decision process:
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B.2.1. Sending an IP packet out for an IoT or a RG
If the IP header contains EzIP Option word, SPR will route it forward
by using the EzIP mechanism (replacing Source Host Number by SPR's
own and filling in Extended Source No. if not already there).
Otherwise, the SPR provides the CG-NAT service (assigning TCP Source
Port number and allowing the packet to masquerade with the SPR's own
IP address, plus creating an entry to the state (port-forward / look-
up / hash) table in anticipation of the reply packet).
B.2.2. Receiving an IP packet from the ER
If a received IP packet includes a valid EzIP Option word, SPR will
provide the EzIP routing service (utilizing the Extended Destination
No. as the Destination Host Number). If only Destination Port number
is present, CG-NAT service will be provided. For a packet with plain
IP header (with neither EzIP nor CG-NAT information), it will be
dropped.
B.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 from the Internet. On the other hand, 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.
B.3.1. Initiating Session request for an IoT
Without regard to whether the IP header is a conventional type or an
EzIP one, 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 the current RG-NAT practice.
B.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 forwarded to the corresponding address. This is the same as
the normal RG-NAT processes in a conventional RG.
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B. If it matches with the IP 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 either of the above two lists could happen by chance. To
address this issue, the following proactive mechanism should be
incorporated in parallel:
C. If the "Destination Port" number is null or matches with
neither of the above two lists, 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
predetermined 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 RG-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 an equivalent means)
knowing the extension number of the destination party. Such process
effectively screens out most of the unwanted callers while serving
the acquaintance expeditiously.
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Appendix C EzIP Realizability
The EzIP scheme proposes a new type of network router, called SPR,
capable of utilizing 240/4 address transported via the Option word
mechanism in the EzIP Header. In particular, EzIP may optimally be
first deployed in the form of a Regional Area Network (RAN) wherever
desired. Each RAN starts from one IPv4 public address to serve up to
256M IoTs. For such a configuration, an SPR will operate with the
degenerated EzIP Header which is identical to the basic IPv4 Header,
except the addresses are from the 240/4 netblock. Since this can be
accomplished by simply expanding the scope of the accessible address
pool within the IPv4 protocol, there is hardly any need to modify the
design of existing routers.
Having been "Reserved for Future Use" for so long (since 1981-09),
however, it is a challenge to identify current equipments that may be
conducive to the use of the 240/4 netblock. Un-documented behaviors,
observed through extensive research and testing of products in-use
and on-the-market as well as public domain firmware, confirm that
certain pairs of router and IoT / PC OS are already partially
supporting this mode of operation. This unexpected discovery sets the
baseline for the following interim report.
C.1. 240/4 Netblock Capable IoTs
A. Open source Xubuntu OS (V.18.04.1) enables a PC to assume both
dynamic and static IP addresses, through the same physical Ethernet
port, simultaneously. The former operates in the default DHCP client
mode with conventional three private netblocks, while the latter
accepts manually set static addresses including those from the 240/4
netblock. Making use of this "dual personality", connectivity between
two similarly equipped PCs can be established first through a
compatible router (described in the next subsection) by "ping"ing
each other with the dynamic address. Using the static 240/4
addresses, the additional networking channel through the same router
can then be confirmed.
B. Several other PC OSs, such as Chrome (V.74.0.3729.125), LinuxMint
V.19 tara (Ubuntu V.4.15.0), Mojave (OSX 10.14.1) and Ubuntu 19.04
(Ubuntu 5.0.0), have been found to behave similarly, although
partially and not as conveniently.
C.2. 240/4 Netblock Capable Routers
A. Open source router firmware OpenWrt (V18.06.1) currently does not
utilize the 240/4 netblock in its DHCP operation, while it would not
reject the process of specifying such but would not function properly
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afterwards. Yet, it transports, in its native configuration, 240/4
addressed "ping" packets between two 240/4 capable PCs anyway.
B. Also, a common RG, TP-Link Archer C20 AC750 (F/W V4_170222 /
0.9.13.16 v0348.0) rejects setting its DHCP pool to use the 240/4
netblock, but transports 240/4 addressed "ping" packets, nonetheless.
C. Similarly, Verizon FiOS-G1100 RG (H/W: 1.03, F/W: 02.02.00.14 UI
Ver: v1.0.388) will not allow its DHCP server to utilize the 240/4
netblock, but transports the 240/4 addressed "ping" packets, just
fine.
D. Other routers, such as LinkSys E3000 (DD-WRT v24-sp2 (05/27/13)
mini (SVN Rev. 21676), have been found to exhibit similar behavior.
E. Furthermore, test data suggest that 240/4 addressed "ping" and
"traceroute" packets from some of the above setups could have
propagated through an IAP's ER (108.30.229.xxx, Verizon's Edge
Router) into the Internet. The addresses (130.81.171.xxx) that they
arrrived at appear to be Verizon's internal routers. If these are not
CRs (Core Routers), at least they are ARs (Aggregate Routers).
C.3. Enhancing an RG
The above observations suggest that Xubuntu OS based PCs are likely
ready to network as 240/4 addressed DHCP clients. To complement this
capability, we need a router that can function as a 240/4 DHCP
server. Although the OpenWrt firmware appears to be closer to this
desired functionality than the TP-Link Router, the source code of the
latter being hardware specific would better facilitate the firmware
enhancement efforts. Accordingly, the following outlines the steps
being planned to bring TP-Link Router and Xubuntu OS based PCs up to
a state for performing the essential SPR functions:
C.3.1. Enhance the TP-Link Router firmware to include the 240/4
netblock in its DHCP pool.
C.3.2. Verify that Xubuntu OS based PCs will accept 240/4 based
DHCP assignment from the enhanced Router above. With this, deactivate
the static address settings in the PCs.
C.3.3. Send 240/4 destined traffic between two Xubuntu PCs to be
sure that it is transported through the Router. Three tests will be
conducted; sending "ping" and "traceroute" packets to confirm the
basic connectivity as well as file transfer to verify TCP/IP
capability.
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C.3.4. A separate second TP-Link Router will then be plugged into
this first Router as a client IoT to verify that it would accept a
240/4 address as its WAN port designation. Based on this, the second
Router will serve as an RG providing the conventional private network
environment (10/8, 172.16/12 and 192.168/16 netblocks) to common
IoTs, allowing them to continue their current operations without
modification, at all.
C.4. SPR Reference Design
The above pair of enhanced Routers can be used as the SPR model for
enahancing industrial grade routers that are capable of the daily
traffic level expected by a RAN.
Note that including 240/4 netblock in the DHCP pool for the LAN of
the first Router and accepting the 240/4 address assignment on the
WAN port of the second Router are two orthogonal capabilities. They
can be implemented in the same physical Router, consolidating both
modifications into one single SPR module.
C.5. RAN Deployment Model
The above SPR reference design is essentially an existing common IPv4
RG with two simple enhancements:
I. Upstream (WAN) port capable of being a DHCP client accepting 240/4
address assignment, in addition to the ordinary IPv4 public address.
II. Downstream (LAN) port providing DHCP service to client IoTs
using the 240/4 netblock, in addition to the three conventional
private netblocks.
By selectively activating these capabilities, three versions of SPRs
can be derived for completing a functional RAN model:
C.5.1. Root / Gateway SPR: This is the first SPR for starting a
RAN from an IPv4 public address. As such, the upstream port of this
SPR should accept a public IPv4 address. And, its downstream port
will use the 240/4 netblock in its DHCP pool.
Note that this particular type of SPR is only needed for a RAN
demonstration setup. In an actual RAN deployment, a proxy gateway
that caches the Internet traffic for improving the operation
efficiency will naturally perform the same function of this Root SPR,
by virtue of being a more capable two-port device.
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C.5.2. Intermediate SPRs: To optimize the performance
requirements on the routing processor, a practical SPR is not
expected to handle all 256M IoTs in a single module. A RAN should
have several layers of SPRs in a tree structure, each handles a
subset of the 240/4 netblock. This architecture enables processing
local traffic locally. Only communications with distance parties need
be consoliated by going through the higher layers of SPRs for
delivery. For this type of SPRs, both their upstream DHCP client port
and downstream DHCP Server pool will operate on sub-240/4 netblocks,
segregated according to the numbering plan in the RAN system design.
C.5.3. RG SPR: To serve existing IoTs on customer premises, this
SPR will be configured to accept a 240/4 address on its upstream
port, while the downstream port assigns addresses from the three
conventional private netblocks to its DHCP client IoTs.
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Appendix D Enhancement of a Commercial RG
Since the 240/4 netblock is just one part of the full IPv4 address
pool, there is nothing special about it. In principle, all we need to
do to utilize it is to include it within the usable ranges of a
router's addresses. However, perhaps because it has been reserved for
so long, hardly anyone has been paying attention to how the 240/4
netblock has been treated in current router programs. An intuitive
assumption is that there may be a database that lists all acceptable
address ranges or netblocks. If so, the EzIP enhancement would entail
adding the 240/4 netblock to the list. On the other hand, the current
approach maybe is based on singling out specific unusable IP
addresses. Then, eliminationg such process is sufficient. It turns
out that a commercial RG product appears to be operating with the
latter approach. From such, the task would become simply commenting
out the program statements that are rejecting the 240/4 netblock.
D.1. Candidate Code for Modification
The following short JavaScript function named "ifip" in the TP-Link
Archer C20 V4 source code has been shown to selectively reject
specific ranges of IP addresses. In particular, Line 1047 uses a "2's
Complement" technique to identify the 240/4 netblock as "PRESERVED",
thus rejecting it. A quick scan of the firmware code in the router
indicates that this function is a popular utility because there are
numerous processes calling for it. So, this should be the best
candidate to start testing our concept.
lib.js:1040:ifip: function(ip, unalert) {
lib.js-1041-if ((ip = $.ip2num(ip)) === false) return $.alert(ERR_IP_FORMAT, unalert);
lib.js-1042-if (ip == -1) return $.alert(ERR_IP_BROADCAST, unalert);
lib.js-1043-var net = ip >> 24;
lib.js-1044-if (net == 0) return $.alert(ERR_IP_SUBNETA_NET_0, unalert);
lib.js-1045-if (net == 127) return $.alert(ERR_IP_LOOPBACK, unalert);
lib.js-1046-if (net >= -32 && net < -16) return $.alert(ERR_IP_MULTICAST, unalert);
lib.js-1047-if (net >= -16 && net < 0) return $.alert(ERR_IP_PRESERVED, unalert);
lib.js-1048-return 0;
lib.js-1049-},
D.2. Proposed Modification
To stop rejecting the 240/4 netblock addressed packets, below is a
modification that comments out Line 1047, a modification that has
been shown to eliminate javascript pre-validation of 240/4 IP
addresses, allowing them to be sent within the router, where a second
layer of validation rejects them in a different way.
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lib.js:1040: ifip: function(ip, unalert) {
lib.js-1041- if ((ip = $.ip2num(ip)) === false) return $.alert(ERR_IP_FORMAT, unalert);
lib.js-1042- if (ip == -1) return $.alert(ERR_IP_BROADCAST, unalert);
lib.js-1043- var net = ip >> 24;
lib.js-1044- if (net == 0) return $.alert(ERR_IP_SUBNETA_NET_0, unalert);
lib.js-1045- if (net == 127) return $.alert(ERR_IP_LOOPBACK, unalert);
lib.js-1046- if (net >= -32 && net < -16) return $.alert(ERR_IP_MULTICAST, unalert);
lib.js-1047- //if (net >= -16 && net < 0) return $.alert(ERR_IP_PRESERVED, unalert);
lib.js-1048- return 0;
lib.js-1049-},
D.3. Performance Verification
Initially, the TP-Link Archer C20 router's GPL source code package
from the manufacturer would not go through compilation process. A
revised version allowed us to build a firmware file. Yet, it failed
in loading into the hardware. Interactions continue with the
manufacturer hoping to resolve this basic issue soon. Unfortunately,
this issue remains pending to this day.
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Appendix E Utilizing Open Source Router Code
An alternative to the above is to make use of open source router
codes for the EzIP implementation. The advantage of this approach is
that once it is verified in one commercial router, interested parties
may then load the same vintage of open source codes to their own
preferred routers for replicating the operation. The challenge to
this approach, however, is that open source codes are "generic" for
supporting a wide range of brands and models. Customization must be
made to adapt it for a specific router model to generate an
executable binary file for the target device as its firmware. As
well, this configuration information will be needed each time the
source code is modified for a new application, such as the EzIP.
Interestingly, such knowledge appeared to be not in an "open"
document. In the process of studying such, we discovered that OpenWrt
was planning to enhance its Linux core which included the removal of
the current restriction on using 240/4. Although their intention was
to be able to use the 240/4 pool as the fourth private netblock, such
capability suited our EzIP scheme just fine. So, we waited for the
release of the OpenWrt 19.07 and further for its more stable OpenWrt
19.07.2 version, before attempting the EzIP application. Below is a
WIP report of our test results based on OpenWrt 19.07.3.
E.1. EzIP Realizability Test Bed
The first step is to create a LAN environment served by a router
utilizing the 240/4 netblock. Upon loaded OpenWrt 19.07.3 into a
commercial TP-Link Archer C20 V4 Router, it operated with 240/4
address pool as if it was the fourth private netblock. IoTs capable
of utilizing 240/4 netblock operated fine under this environment.
Specifics of this effort is reported on Page 2 of the following
whitepaper:
https://www.avinta.com/phoenix-
1/home/RegionalAreaNetworkArchitecture.pdf
E.2. RAN Architecture Demonstration
The goal of a RAN Demo is to transport a conventional IPv4 (public)
netblock addressed IP packet though a 240/4 environment and then back
to an IPv4 private network operating with one of the three
conventional netblocks (10/8, 172.16/12 or 192.168/16). This process
will increase the assignable addresses, while allowing all IoTs to
retain their existing operation characteristics. To simuate such a
RAN, we need a RG that can operate as a client in the 240/4
environment established by Apppendix E.1. above, while maintaining
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its DHCP LAN service to a conventional private network. It has been
identified that besides OpenWrt 19.07.3 supported routers, at least
one RG (Sagemcom RAC2V1S) provided by Spectrum cable service delivers
this function. Page 4 of the above whiitepaper details the
configuration and operation of such a RAN. In addition, during past
experiments, RG for Verizon's FiOS service was found to be already
transporting 240/4 addressed packets, as well. Combined, this means
that most of existing private networks may continue normal operations
under the inserted RAN environment while the latter provides
assignable 240/4 addresses to additional premises for expanding the
system capacity.
E.3. EzIP Compatible Routers
At the last count, there were 1091 branded router models supported by
OpenWrt 21.02.1. In fact, it turns out that for an existing IPv4
router to become an SPR for supporting the EzIP operation, all needs
be done is "disabling the existing program code that has been
disabling the use of the 240/4 netblock". Such effort is expected to
be rather minimal for parties having control of the relevant program
source codes. Consequently, most existing IPv4 routers should be able
to support EzIP through finite enhancement processes, even if they
are currently not supported by OpenWrt 19.07.3 (or newer).
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Appendix F Sub-Internet
Since each RAN serving up to 256M IoTs can be operated with just one
IPv4 address for interacting with the Internet, it follows that if a
buffering device is inserted inline between the two for relaying
requests to the Internet and caching the responses from the Internet,
a RAN could behave like a pseudo (although miniature) Internet from
its clients' perspective for practical purposes. Such buffering
function may be provided by a Gateway module which is commonly used
by institutions for serving their respective LANs. Terminology wise,
this Gateway is called Transparent / Intercepting Proxy as compared
to other forms of cache proxies such as Peer Proxy, Reverse Proxy,
etc. Combining a RAN with a Gateway, a Sub-Internet is formed that
can operate as a stand-alone module to provide Internet services.
Below is a brief description of a Gateway for serving a RAN.
F.1. Gateway Configuration
Besides the above mentioned caching functions, a Gateway, being a two
port device, can also bridge two different netblocks together. This
is convenient because the Gateway's upstream port uses the
conventional public IPv4 address while the downstream port supports
the RAN that runs on 240/4 netblock. However, this is not a
necessity, because the root SPR in the RAN is configured, by default,
as a DHCP client so that it can work from either netblock, anyway.
F.2. Gateway Setup
A Raspberry Pi4 single board computer loaded with Raspaian Buster
Linux for Pi4 OS is used as the base for running a cache proxy
(squid/oldstable,now 4.6-1+deb10u6 armhf) to serve as a Transparent
Proxy.
F.3. Sub-Internet Operation
Several basic functions, such as web access, file transfer, eMial,
etc. are being tested. Initial results are encouraging. The WIP (Work
In Progress) file posted at the following URL has been updated to
report the latest results of the ongoing efforts.
https://www.avinta.com/phoenix-1/home/SubInternet_RJC.pdf
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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
Abhay Karandikar
Director, India Institute of Technology Kanpur
Kanpur - 208 016, U.P., India
Phone: _(+91)512 256 7220
Email: Director@IITK.ac.in
Ramamurthy R. Ati
Avinta Communications, Inc.
142 N. Milpitas Blvd., #148, Milpitas, CA 95035-4401 US
Phone: _+1(408)458-7109
Email: rama_ati@outlook.com
David R. Crowe
Wireless Telecom Consultant and Forensic Expert Witness
102 Point Drive NW, Calgary, Alberta, T3B 5B3, Canada
Phone: _+1(403)289-6609__
Email: David.Crowe@CNP-wireless.com
Chen, et al. Expires June 8, 2022 [Page 56]