Internet DRAFT - draft-augustyn-intarea-ipref
draft-augustyn-intarea-ipref
Internet Engineering Task Force W. Augustyn, Ed.
Internet-Draft 25 September 2023
Intended status: Standards Track
Expires: 28 March 2024
IP Addressing with References (IPREF)
draft-augustyn-intarea-ipref-02
Abstract
IP addressing with references, or IPREF for short, is a method for
end-to-end communication across different address spaces normally not
reachable through native means. IPREF uses references to addresses
instead of real addresses. It allows to reach across NAT/NAT6 and
across protocols IPv4/IPv6. It is a pure layer 3 addressing feature
that works with existing network protocols.
IPREF forms addresses made of context addresses and references.
These addresses are publishable in Domain Name System (DNS). Any
host in any address space, including behind NAT/NAT6 or employing
different protocol IPv4/IPv6, may publish its services in DNS. These
services will be reachable from any address space, including those
running different protocol IPv4/IPv6 or behind NAT/NAT6, provided
both ends support IPREF.
IPREF is especially useful for transitioning to IPv6.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 28 March 2024.
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Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
1.2. IPREF Terminology . . . . . . . . . . . . . . . . . . . . 5
2. IPREF Overview . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. References . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. IPREF Addresses . . . . . . . . . . . . . . . . . . . . . 6
2.3. Gateways and Encoding Networks . . . . . . . . . . . . . 7
2.4. Traversing Address Spaces . . . . . . . . . . . . . . . . 7
2.5. Traversing Address Spaces in Detail . . . . . . . . . . . 9
2.6. Embedding References in IP Packets . . . . . . . . . . . 12
2.6.1. IPv4 Option . . . . . . . . . . . . . . . . . . . . . 12
2.6.2. IPv6 Extension Header . . . . . . . . . . . . . . . . 12
2.6.3. UDP Tunnel . . . . . . . . . . . . . . . . . . . . . 13
2.7. Name Resolution Support . . . . . . . . . . . . . . . . . 13
3. DNS with IPREF . . . . . . . . . . . . . . . . . . . . . . . 13
3.1. DNS Records . . . . . . . . . . . . . . . . . . . . . . . 14
3.2. Local Network Resolvers . . . . . . . . . . . . . . . . . 15
3.3. Detecting Published IPREF Addresses . . . . . . . . . . . 15
3.4. DNSSEC compatibility . . . . . . . . . . . . . . . . . . 15
3.5. IPREF Address Literals . . . . . . . . . . . . . . . . . 15
4. Using IPREF for Transitioning to IPv6 . . . . . . . . . . . . 15
4.1. Transitioning Process . . . . . . . . . . . . . . . . . . 17
5. Related Technologies . . . . . . . . . . . . . . . . . . . . 20
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
7. Security Considerations . . . . . . . . . . . . . . . . . . . 21
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
8.1. Normative References . . . . . . . . . . . . . . . . . . 21
8.2. Informative References . . . . . . . . . . . . . . . . . 22
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 22
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1. Introduction
Some 25 years ago, it became clear that the 32 bit address space of
the IP protocol was too small for the growing Internet. An effort to
avert the impending 'shortage of IP addressees', as the problem was
referred to at the time, led to development of a new IP protocol
named version 6. That protocol, referred to as IPv6, had a larger
address space thus instantaneously solving the problem.
Unfortunately, it created another problem. It operated in a
different, incompatible address space than the existing IP protocol,
referred to since as IPv4. In this way, two different address
spaces, inaccessible to each other, have been created.
Meanwhile, a grass roots effort led to development of another
solution to the 'shortage of IP addresses' problem that was
compatible with existing IPv4 protocol. IPv4 address space was
extended by rewriting network addresses. That technique, since
widely known as NAT, effectively created an address space hierarchy.
At the top of the hierarchy, there was the original 32 bit address
space. These addresses, at the edge of hierarchy, were translated
into and from another set of addresses belonging to so called
'private ranges'. These addresses formed new address spaces. They
were 32 bit wide but only 24 bit subsets were used in practice.
Together with the top hierarchy, they produced a 56 bit address space
for IPv4. Another variant, known as 'carrier grade NAT', added
another level of hierarchy which extend total address space to 72
bits. This approach averted the shortage of IP addresses, but it
achieved it at a cost of creating another problem. Namely, it
created millions of address spaces inaccessible to one another.
These new address spaces were not equal value, they were mostly
useful for clients accessing servers within their own address spaces
or within the space at the top of the hierarchy, commonly referred to
as 'global IP addresses'.
As a result, the Internet evolved into a collection of a large number
of generally inaccessible address spaces with two incompatible
network protocols.
There were attempts at improving the situation which went in two
directions. There were attempts aiming to solve access across
address spaces within the same protocol, typically referred to as
'NAT traversal solutions', and there were attempts aiming to bridge
IPv4/IPv6 divide. All of these attempts resulted in partial
solutions with substantial limitations. We could call them nicely
'focused'. The ones dealing with IPv4/IPv6, like NAT64/SIIT, were
asymmetrical, worked differently in one direction than the other,
didn't scale well, required global IPv4 addresses, couldn't traverse
NAT. The ones dealing with NAT traversal, like STUN or NAT-T
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collection, didn't work across protocols IPv4/IPv6, were very
limited, dealing mostly with port manipulation, never truly solving
NAT traversal.
The result of these attempts was a hodgepodge of limited, mostly
lacking, poorly scaling, half measures which left these millions of
different address spaces still generally inaccessible to one another.
A closer analysis of these different solutions reveals they suffer
great difficulties primarily because they try to render necessary
address transformations too early. IPREF takes a different approach.
It is based on the observation that the originating hosts do not have
to know what the destination addresses are, or what protocol they
belong to. Thus, IPREF uses references to addresses rather than real
addresses. This approach works for both NAT traversal as well as for
protocol traversal since both problems are substantially the same.
The one difference being having to repackage packets on the IPv4/IPv6
boundary. Such repackaging requires sufficient compatibility between
the protocols which fortunately exists.
With this approach, IPREF does not need to negotiate anything. It
does not need any external devices, any shared configurations. It
does not require allocating of any global IP addresses. The result
is a highly scalable solution that works over NAT, NAT6, filters, and
across IPv4/IPv6. All of the millions of different address spaces,
whether behind NAT/NAT6, or across IPv4/IPv6 may now communicate with
one another using IPREF.
In the background to all the above, there is an ongoing effort to
covert every IPv4 network out there to IPv6. The idea is to run only
one protocol everywhere which would simplify many issues including
address space accessibility. This is a long term effort, decades
away. IPREF does not conflict with it. Rather, it provides an
excellent tool in achieving the objective. It does this in a least
expensive, least risky manner which also shortens the conversion time
substantially. Compared to traditional strategies, which use dual
stacks and translator devices all requiring allocation of IPv4
addresses, IPREF allows very clean strategies without IPv4 pollution.
It relies only on pure IPv6 Internet, allows to drop IPv4 Internet
early, and transitions to pure IPv6 networks in a single step.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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1.2. IPREF Terminology
IPREF - short name referring to technology described in this
document, pronounced I-P-REF
context address - a native address component of an IPREF address
reference - an unsigned integer component of an IPREF address
IPREF address - addressing unit used with IPREF, a combination of a
context address and a reference
encoding network - network representing IPREF addresses in native
form
IPREF gateway - a device, or software component, that performs IPREF
address rewriting
2. IPREF Overview
IPREF is a method for communication across different address spaces,
that is those that cannot be reached through native means of a
network protocol. Examples of such address spaces are networks
behind NAT, NAT6, or filters, as well as networks employing different
network protocols such as IPv4/IPv6.
Key characteristics of IPREF:
* massively scalable
* cross protocol, cross address space (such as NAT/NAT6)
* strictly layer 3 (no port manipulation, all ports available)
* addresses publishable in DNS
* no need for external translators or shared configurations
* no need for global IPv4 addresses
2.1. References
A common problem with cross address space communication is to decide
how to deal with addressing. Communicating peers cannot interpret
each other's addresses therefore some other method of directing
packets to proper destinations must be devised.
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IPREF solves this problem by using references to addresses rather
than actual addresses. The references are then evaluated within each
address space to render proper native addresses suitable for
forwarding. The evaluation is performed at each address space
independently. As a result the same references render different
addresses at different address spaces.
References are unsigned integers meaningful only in the context of
the address space they pertain to. Local administrators allocate
values to references and assign their meaning. They may divide a
reference into fields for any purpose believed useful. For example,
the fields may reflect different sources of allocations, or provide
extra security bits, or provide load balancing hints, etc. Peers are
unaware of these fields and treat references as opaque values.
2.2. IPREF Addresses
IPREF uses references to addresses in lieu of actual addresses. Such
references need context to be meaningful, therefore IPREF uses
addressing units that combine a context address, which MUST be a
native address, and a reference. These addressing units are called
IPREF addresses.
┌───────────────────┬───────────────────┐
│ context address │ reference │
└───────────────────┴───────────────────┘
198.51.100.11 + 700
2001:db8::abc:11 + 700
Figure 1: IPREF address
The context address portion of an IPREF address is an address within
adjacent address space. Typically, this is the Internet, so this is
usually an Internet address of an edge router of the source or
destination network. Other addresses known to the network may also
be used.
References are allocated by administrators of respective address
spaces. The references may only refer to hosts from these address
spaces. Thus, the destination references are allocated by the
administrators of the destination networks while the source
references are allocated by the administrators of the source
networks. There are no conflicts and there is no need for
negotiations. Each peer defines their own references and accepts
peer references as opaque values.
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Figure 1 shows two examples of IPREF addresses. In the notation, a
plus sign '+' separates context address from the reference. A packet
carries two IPREF addresses: a source IPREF address and a destination
IPREF address.
IPREF addresses are publishable in DNS.
2.3. Gateways and Encoding Networks
IPREF addresses are placed in packets by gateways. The gateways must
be installed at each address space participating in IPREF
communication. Intermediate address spaces, such as the Internet,
don't need gateways.
The gateways inject and remove IPREF addresses as packets leave and
enter local networks. They also encode IPREF addresses for internal
use as local network protocols only understand native addresses. The
encoding networks are local private networks to which the gateways
map IPREF addresses. For example, IPv4 networks could use a 10/8
network while IPv6 networks could use an fd::/64 network for the
purpose. For local hosts, these encoded addresses represent peers
they communicate with. The peers appear as if on the local network.
This is common with cross protocol communication or more generally
with cross address space communication. The gateways replace these
encoded addresses with IPREF addresses when sending packets outside
local networks.
2.4. Traversing Address Spaces
Conceptually, packets travel through address spaces based on source
and destination IPREF addresses. This is analogous to IP protocols.
The IPREF addresses are interpreted at each address space to render
native addresses for forwarding.
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Network A │ Internet │ Network B
src: 2001:db8::9 + 1579 2001:db8::9 + 1579 2001:db8::9 + 1579
dst: 2001:db8::8 + 2466 2001:db8::8 + 2466 2001:db8::8 + 2466
🡳 🡳 🡳
src: 172.17.1.75 2001:db8::9 fdee:eeee::5951
dst: 10.128.48.62 2001:db8::8 2001:db8:b::28
┌──────┐ IPv4 │ IPv6 │ IPv6 ┌──────┐
│ host │.75┃ ┃ │ host │
│ A1 ├───┨ ┏━━━━━━━┓ │ │ ┏━━━━━━━┓ ┠───┤ B4 │
└──────┘ ┃ ┃ IPREF ┃:9 :8┃ IPREF ┃ ┃ └──────┘
┠──┨ g-way ┠───── Internet ─────┨ g-way ┠──┨
┌──────┐ ┃ ┃ GWA ┃ ┃ GWB ┃ ┃:28┌──────┐
│ host ├───┨ ┗━━━━━━━┛ │ │ ┗━━━━━━━┛ ┠───┤ host │
│ A3 │ ┃ ┃ │ B6 │
└──────┘ │ │ └──────┘
Figure 2: traversing address spaces
For example, in Figure 2, if host A1 wanted to send a packet outside
of its own address space to host B6, it would need a source IPREF
address for itself and a destination IPREF address for B6.
The destination IPREF address of host B6, presumably a server, would
be allocated by the admin of network B where B6 resides. It would
normally be advertised in DNS. The source IPREF address of A1,
presumably a client, would normally be allocated dynamically by the
local IPREF gateway.
As packets travel from source to destination, the following takes
place:
* At network A, the IPREF source address is interpreted as a native
address of host A1. The destination IPREF address is interpreted
as some local private address on the encoding network. The
encoding allows host A1 to place native addresses in the packet.
The IPREF gateway will replace both source and destination
addresses with their IPREF equivalents. It will also repackage
IPv4 packets into IPv6 since the next address space is IPv6.
* In the transient address space, the Internet, IPREF addresses are
interpreted as well even though the network is unaware of that.
In the transient networks only context addresses are used while
the references are ignored. This is accomplished by placing
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context addresses (which must be native) in the respective source
and destination fields of the native network protocol. In this
way, transient networks, such as the Internet, don't need to know
anything about IPREF.
* At network B, the IPREF source address is interpreted as some
local private address on the encoding network. The IPREF
destination address is interpreted as the native address of host
B6. In this way, a packet originating at an IPv4 host A1 reaches
an IPv6 host B6.
On the way back, source and destination addresses are reversed and
their interpretation follows the same pattern, thus a reply packet
originating at an IPv6 host B6 reaches an IPv4 host A1.
In the example, network A may be IPv4 or IPv6, the Internet may be
IPv4 or IPv6, and network B may be IPv4 or IPv6. In any combination,
a packet traveling through these address spaces would be processed in
the same manner and it would reach its destination in the same way.
2.5. Traversing Address Spaces in Detail
Network A │ Internet │ Network B
┌──────┐ IPv4 │ IPv6 │ IPv6 ┌──────┐
│ host │.75┃ ┃ │ host │
│ A1 ├───┨ ┏━━━━━━━┓ │ │ ┏━━━━━━━┓ ┠───┤ B4 │
└──────┘ ┃ ┃ IPREF ┃:9 :8┃ IPREF ┃ ┃ └──────┘
┠──┨ g-way ┠───── Internet ─────┨ g-way ┠──┨
┌──────┐ ┃ ┃ GWA ┃ ┃ GWB ┃ ┃:28┌──────┐
│ host ├───┨ ┗━━━━━━━┛ │ │ ┗━━━━━━━┛ ┠───┤ host │
│ A3 │ ┃ ┃ │ B6 │
└──────┘ │ │ └──────┘
Internet ifc: 2001:db8::9 Internet ifc: 2001:db8::8
Local net A: 172.17.1.0/24 Local net B: 2001:db8:b::/64
Encoding net: 10.128.0.0/10 Encoding net: fdee:eeee::/64
Host A1: 172.17.1.75 Host B6: 2001:db8:b:28
DNS A1: (none) DNS B6: 2001:db8::8 + 2466
Figure 3: traversing address spaces in detail
Let's say an IPv4 host A1 wants to send a packet to an IPv6 host B6:
1. Host A1 finds out the address of host B6
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Host A1 issues a DNS query for host B6. The query goes through
the local resolver. Local resolver receives a response:
B6 has address: 2001:db8::8 + 2466
Since local hosts don't understand IPREF addresses, the resolver
asks gateway GWA to allocate an encoded address for it. The
gateway responds:
map: 2001:db8::8 + 2466 = 10.128.48.62
The resolver returns the encoded result of the DNS query to host
A1:
B6 has address: 10.128.48.62
2. Host A1 sends a packet out to B6
Host A1 places its own address as source and the address of host
B6 returned by the local resolver as destination.
packet out: | 172.17.1.75 | 10.128.48.62 | payload |
3. Packet arrives at gateway GWA
packet in: | 172.17.1.75 | 10.128.48.62 | payload |
The gateway notices that it does not have mapping for the source
address, so it creates one on the fly:
map: 172.17.1.75 = 2001:db8::9 + 1579
It replaces source address with the just created corresponding
IPREF address. It replaces encoded destination address with the
original IPREF address returned by the DNS query. It also
repackages IPv4 packet into IPv6 since the Internet is IPv6.
packet out: | 2001:db8::9 + 1579 | 2001:db8::8 + 2466 | payload |
4. Packet arrives at gateway GWB
packet in: | 2001:db8::9 + 1579 | 2001:db8::8 + 2466 | payload |
The gateway notices that it does not have encoding for the source
IPREF address, so it creates one on the fly:
map: 2001:db8::9 + 1579 = fdee:eeee::5951
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It replaces source IPREF address with the just created local
encoded address. It replaces destination IPREF address with the
local address of host B6.
packet out: | fdee:eeee::5951 | 2001:db8:b::28 | payload |
5. Packet arrives at host B6
packet in: | fdee:eeee::5951 | 2001:db8:b::28 | payload |
Host B6 recognizes destination address as its own and consumes
the packet. OS passes the packet to an application implied by
layer 4.
6. Host B6 sends a reply back to A1
Host B6 gets a reply payload from the application, swaps source
and destination addresses, and sends the packet back to A1.
packet out: | 2001:db8:b::28 | fdee:eeee::5951 | payload |
7. Packet arrives at gateway GWB
packet in: | 2001:db8:b::28 | fdee:eeee::5951 | payload |
The gateway replaces local source address with corresponding
IPREF address previously allocated and advertised in DNS. It
replaces destination local encoded address with the corresponding
IPREF address from mapping created earlier.
packet out: | 2001:db8::8 + 2466 | 2001:db8::9 + 1579 | payload |
8. Packet arrives at gateway GWA
packet in: | 2001:db8::8 + 2466 | 2001:db8::9 + 1579 | payload |
The gateway replaces source IPREF address with the corresponding
local encoded address from mapping created earlier. It replaces
destination IPREF address with the local address of host A1. It
also realizes that the local network is IPv4, so it repackages
the packet into IPv4.
packet out: | 10.128.48.62 | 172.17.1.75 | payload |
9. Packet arrives at host A1
packet in: | 10.128.48.62 | 172.17.1.75 | payload |
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Host A1 recognizes destination address as its own and consumes
the packet. OS passes the packet to the application that sent
the original packet.
At this point any missing mappings have been allocated. Subsequent
packet exchange continues without additional allocations.
2.6. Embedding References in IP Packets
References are network layer entities therefore the most natural
place for embedding them would be network layer headers, such as IPv4
options or IPv6 extension headers.
Unfortunately, many Internet Service Providers drop options and
extension headers for various reasons. Even if they don't, routers
tend to put them on a slow processing path resulting in poor
performance. For that reason, the most reliable way to embed
references is to place them in the payload. One common technique of
accomplishing this is tunneling where references could be made a part
of the payload.
2.6.1. IPv4 Option
With IPv4, references may be embedded in an IPv4 header option
[RFC791]. It would be a new option type. It would contain an octet
with option type and option number, an octet with length, and two
octets reserved for possible future use while padding to four octet
boundary. The source and destination references would then follow.
A new option number would be registered with IANA. Until then,
experimental option, 30, could be used.
2.6.2. IPv6 Extension Header
With IPv6, references may be embedded in an IPv6 extension header
[RFC8200]. It would be a new header type. It would contain an octet
with next header type value, an octet with length, and two octets
reserved for possible future use. This would be followed by four
octets of padding to 8 octet boundary. Padding octets would not be
intended for any future use. The source and destination references
would then follow.
A new protocol type would be registered with IANA. Until then,
experimental protocol, 254, could be used.
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2.6.3. UDP Tunnel
Placing references in a UDP tunnel works for both IPv4 and IPv6. In
both cases, the references are embedded in the form of respective
options or extension headers. In addition, a tunnel encapsulation
record is added. The order of items is as follows:
UDP header
Tunnel encapsulation record
IPREF option
Packet payload
The encapsulation record would consist of four octets. First octet
would contain the value of TTL copied from the original IP header.
The second octet would contain protocol number copied from the
original IPv4 header or next header value form an IPv6 extension
header. The third octet would report number of hops detected for
incoming packets. The fourth octet would be reserved for possible
future use while padding to 4 octet boundary. The IPREF option would
follow in the format matching respective IP protocol, IPv4 or IPv6.
The tunnel would operate at port 1045. This value would be
registered with IANA.
2.7. Name Resolution Support
IPREF gateways provide mapping support for name resolution services
such as DNS. When resolving queries on behalf of local hosts, all
returned IPREF addresses must be mapped to native addresses of the
local network protocol. Typically, a subnet on a private network is
dedicated for the purpose. That subnet is used just for encoding,
there are no real hosts with these addresses. There may be a need to
standardize on how resolvers communicate with gateways to obtain such
mappings.
3. DNS with IPREF
IPREF takes full advantage of DNS [RFC1035]. Local networks may
publish IPREF addresses of any services hosted on local networks.
Standard DNS servers may be used for the purpose.
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Network A │
╔═══════╗
┌──────┐ │ ║ publc ║
│ host │.75┃ ┌────────────╢ DNS ║ A3 AA 2001:db8::9 + 1733
│ A1 ├───┨ ┏━━━┷━━━┓ │ ║ servr ║ ────────>
└──────┘ ┃ ┃ IPREF ┃:9 ╚═══════╝
┠──┨ g-way ┠─────
┌──────┐ ┃ ┃ GWA ┃
│ host ├───┨ ┗━━━┯━━━┛ │ Internet
│ A3 │ ┃ │ ╔═══════╗
└──────┘ │ │ ║ other ║
│ ║ ╔═══════╗
▲ ╔═══╧═══╗ │ ║ ║ other ║
│ ║ local ║ <─────── ╚═║ ╔═══════╗
╰──── ║ DNS ║ B6 AA 2001:db8::8 + 2466 ║ ║ other ║
║ rslvr ║ ╚═║ DNS ║
╚═══════╝ │ ║ servr ║
╚═══════╝
Figure 4: DNS with IPREF
For resolution of DNS names, a modified recursive resolver is
required because IPREF addresses are different from IPv4 and IPv6
addresses. The resolver must recognize them in addition to native IP
addresses.
3.1. DNS Records
IPREF addresses are unlike well known IPv4 addresses or IPv6
addresses. These addresses consist of two components which must be
considered as a single address entity. It is not possible to
separate references from their companion context addresses. For that
reason, there is a need for a new resource record type. The new
record type is tentatively called AA. This record type has not been
registered yet. Until such time, a TXT record may be used instead.
The TXT record simply holds a textual representation of an AA record.
Here are some examples of what the records might look like:
Host-B4 AA 198.51.100.22 + 400
Host-A5 AA net-A + 500
Host-A5 AA 2001:db8::abc:11 + 700
Host-A5 TXT "AA net-A + 500"
The IP portion may be provided numerically or as a domain name. The
format for the reference would allow unsigned decimal integers as
well as unsigned hex integers. Other formats may be defined as well.
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3.2. Local Network Resolvers
Local network resolvers must recognize IPREF addresses returned by
DNS queries. They must also be capable of encoding them into native
IP addresses in consultation with IPREF gateways. This is shown in
Figure 4 as a line connecting local DNS resolver with IPREF gateway
GWA. Encoding is needed because local hosts do not understand IPREF
addresses. Instead, local hosts use encoded equivalents which are
then replaced with the actual IPREF addresses by the gateways. There
may be a need to standardize on how resolvers communicate with
gateways.
3.3. Detecting Published IPREF Addresses
All published IPREF addresses must be communicated to local IPREF
gateways so that they can properly map destination addresses of
incoming packets. This is reflected in Figure 4 by a line connecting
public DNS server with IPREF gateway GWA. There is a number of ways
to accomplish this. There may be a need to standardize on how this
should be done to allow interoperability between different gateways
and different DNS servers.
3.4. DNSSEC compatibility
IPREF address records may be protected by DNSSEC. Packets leaving
local networks contain the exact addresses returned from DNS.
Internally, local hosts use encoded versions of these addresses which
complicates things a little but the gateways replace them with the
original IPREF addresses listed in DNS before sending packets out of
the local network.
3.5. IPREF Address Literals
DNS is immensely useful and it is considered a necessary component of
IP networking. But IP networking does not relay on DNS. It works
just fine with IP address literals entered and distributed manually.
Similarly, IPREF does not rely on DNS. It is possible to use IPREF
address literals in a manner similar to IP. The addresses would
still need to be encoded by the gateways. They would be entered
manually at gateways first, then their encoded equivalents would be
distributed to hosts, possibly as entries in /etc/hosts files.
4. Using IPREF for Transitioning to IPv6
Transitioning to IPv6 with IPREF offers significant benefits to both
the transitioning organizations as well as to the Internet service
providers, carriers, and operators.
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* needs only pure IPv6 Internet (no need for IPv4 services or
translators)
* transitions directly to pure IPv6 (no dual stacks, no two-step
transition)
* no need for global IPv4 addresses
* eliminates NAT/NAT6 (all hosts reachable, all ports available)
* plays nicely with DNSSEC
* allows to drop IPv4 Internet early
* allows to transition at own pace
* massively scalable
* dramatically speeds up adoption of IPv6 Internet
* huge cost savings
The ability to drop IPv4 Internet early is the key to speeding up
adoption of IPv6 Internet.
Relying on only pure IPv6 Internet and transitioning to pure IPv6
greatly simplifies network designs and operations. Transition based
on IPREF produces cleaner, simpler networks and a cleaner, simpler
Internet.
The ability to transition at own pace, service by service, subnet by
subnet results in huge reduction in costs and risks.
Traditional transition strategies have a structural deficiency. They
perpetuate IPv4 addressing. Thus they extend the life of IPv4
Internet endlessly, to the point it may not be possible to take it
down. This is caused by the use of dual stacks and a collection of
translation devices such as NAT64/SIIT/464XLAT which all require
allocation of IPv4 addresses. They are set up first, before
transition takes place, and cannot be taken down until AFTER all
networks out there transition to IPv6. This may take decades to
happen if ever.
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IPREF does not have such deficiencies. It does not use dual stacks
and it does not use any translator devices that rely on IPv4
addresses. IPREF gateways are set up first which makes it possible
to drop IPv4 Internet very early. The actual transition of the local
networks takes place after the Internet has been switched to IPv6.
In this way, the life of the IPv4 Internet is never extended by the
transitioning effort.
4.1. Transitioning Process
Transitioning process with IPREF takes advantage of IPREF's
flexibility to operate in all combinations of address spaces:
network A Internet Network B
1 IPv4 IPv4 IPv4 -- starting point
2 IPv4 IPv4 IPv6 (possible but rare)
3 IPv4 IPv6 IPv4 -- after dropping IPv4 Internet
4 IPv4 IPv6 IPv6 -- common during transition
5 IPv6 IPv4 IPv4 (same as 2)
6 IPv6 IPv4 IPv6 (possible but rare)
7 IPv6 IPv6 IPv4 (same as 4)
8 IPv6 IPv6 IPv6 -- completed transition
Because different address spaces - network A, Internet, and network B
- are processed independently by IPREF, it decouples transitioning
process at local networks from transitioning efforts at peer
networks. It also decouples the process from the Internet protocol
thus allowing dropping of IPv4 Internet early.
1. Starting point
Network A │ Internet │ Network B
┏━━━━━━━┓ │ IPv6 │ ┏━━━━━━━┓
┫ IPREF ┣ ┫ IPREF ┣
IPv4 ┃ g-way ┃ │ IPv4 │ ┃ g-way ┃ IPv4
════════╗ ┫ GWA ┣ ╔════════════════════╗ ┫ GWB ┣ ╔════════
║ ┗━━━━━━━┛ ║ │ │ ║ ┗━━━━━━━┛ ║
╚═════════════╝ ╚═════════════╝
│ │
IPREF gateways are installed but not used. All connectivity is
pure IPv4.
2. Switching traffic to IPREF
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Network A │ Internet │ Network B
IPv6 ┏━━━━━━━┓ │ IPv6 │ ┏━━━━━━━┓
╌ ╌ ╌ ╌ ╌ ╌┫ IPREF ┣ ┫ IPREF ┣
IPv4 ┃ g-way ┃ │ IPv4 │ ┃ g-way ┃ IPv4
═══════════┫ GWA ┣══════════════════════════┫ GWB ┣═══════════
┗━━━━━━━┛ │ │ ┗━━━━━━━┛
│ │
IPREF gateways are configured. References are assigned. Traffic
goes through the gateways. All services subject to transition
are now accessed via IPREF. Some local IPv6 networks may be set
up but not used yet.
Transition process at local networks is decoupled from any
transition effort taking place at peer networks. It is also
decoupled from the type of Internet connection. Traffic between
gateways remains over IPv4 Internet until both ends connect to
IPv6 Internet. This does not affect transitioning of local
networks to IPv6.
3. Connecting to IPv6 Internet
Network A │ Internet │ Network B
IPv6 ┏━━━━━━━┓ │ IPv6 │ ┏━━━━━━━┓
═══════════┫ IPREF ┣╌ ╌ ╌ ╌ ┫ IPREF ┣
IPv4 ┃ g-way ┃ │ IPv4 │ ┃ g-way ┃ IPv4
═══════════┫ GWA ┣══════════════════════════┫ GWB ┣═══════════
┗━━━━━━━┛ │ │ ┗━━━━━━━┛
│ │
Each side connects to IPv6 Internet at their own pace. Local
IPv6 networks may start to appear. These are pure IPv6 networks,
no dual stacks. Connectivity between local IPv4/IPv6 networks is
provided by the same IPREF gateway that connects to remote peers.
Clients located on local IPv6 networks can reach servers located
on local IPv4 networks or remote networks (IPv4 or IPv6).
Similarly, servers on local IPv6 network can be reached from
clients located on local IPv4 networks as well as from remote
networks (IPv4 or IPv6).
4. Switching gateway traffic to IPv6
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Network A │ Internet │ Network B
IPv6 ┏━━━━━━━┓ │ IPv6 │ ┏━━━━━━━┓ IPv6
═══════════┫ IPREF ┣══════════════════════════┫ IPREF ┣╌ ╌ ╌ ╌ ╌ ╌
IPv4 ┃ g-way ┃ │ IPv4 │ ┃ g-way ┃ IPv4
═══════════┫ GWA ┣╌ ╌ ╌ ╌ ╌ ╌ ╌ ╌ ╌ ╌ ╌ ╌ ╌ ┫ GWB ┣═══════════
┗━━━━━━━┛ │ │ ┗━━━━━━━┛
│ │
After both ends connect to IPv6 Internet, IPREF addresses may be
changed to switch traffic to go over the IPv6 Internet.
Transition process at local networks is not affected by this
change.
5. Dropping IPv4 Internet
Network A │ Internet │ Network B
IPv6 ┏━━━━━━━┓ │ IPv6 │ ┏━━━━━━━┓ IPv6
═══════════┫ IPREF ┣══════════════════════════┫ IPREF ┣╌ ╌ ╌ ╌ ╌ ╌
IPv4 ┃ g-way ┃ │ │ ┃ g-way ┃ IPv4
═══════════┫ GWA ┣ ┫ GWB ┣═══════════
┗━━━━━━━┛ │ │ ┗━━━━━━━┛
│ │
IPv4 Internet may now be dropped. It takes place early in the
process. From the Internet's point of view, transition to IPv6
has completed. The Internet does not have to wait until every
local networks transitions to IPv6. As sites keep dropping their
IPv4 Internet connections, the entire IPv4 Internet may be taken
down well before every network out there completes its
transition. This is possible thanks to decoupling of the
transitioning at local networks from the Internet protocol.
From local networks point of view, the disappearance of IPv4
Internet is invisible. It does not affect local transitioning
process.
6. Switching to IPv6 independently
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Network A │ Internet │ Network B
IPv6 ┏━━━━━━━┓ │ IPv6 │ ┏━━━━━━━┓ IPv6
═══════════┫ IPREF ┣══════════════════════════┫ IPREF ┣═══════════
IPv4 ┃ g-way ┃ │ │ ┃ g-way ┃
═══════════┫ GWA ┣ ┫ GWB ┣
┗━━━━━━━┛ │ │ ┗━━━━━━━┛
│ │
Each respective local network switches to IPv6 independently and
may progress at its own pace. It may elect to stay with a mix
IPv4/IPv6 for as long as necessary or convenient. This does not
affect other networks.
7. Completing transition
Network A │ Internet │ Network B
IPv6 ┏━━━━━━━┓ │ IPv6 │ ┏━━━━━━━┓ IPv6
═══════════┫ IPREF ┣══════════════════════════┫ IPREF ┣═══════════
┃ g-way ┃ │ │ ┃ g-way ┃
┫ GWA ┣ ┫ GWB ┣
┗━━━━━━━┛ │ │ ┗━━━━━━━┛
│ │
Transition is completed when each side switches its internal
network to IPv6. All internal networks are pure IPv6. The
Internet is also pure IPv6. IPREF gateways may be removed, or
they may remain in place to allow communication with third party
sites that have not transitioned.
5. Related Technologies
IPREF works well with related technologies. It does not create
conflicts and it does not attempt to step on their functionality.
* IPv4 - IPREF does not replace IPv4, it is an optional add-on to
enhance IPv4 capabilities in the area of address rewriting. It
relies on IPv4 in all other functions of a network protocol.
* IPv6 - IPREF does not replace IPv6, it is an optional add-on to
enhance IPv6 capabilities in the area of address rewriting. It
relies on IPv6 in all other functions of a network protocol.
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* NAT - IPREF is an address rewriting technology but operates
differently than NAT. It operates exclusively at the network
layer. It does not reach to upper layer protocols or lower layer
protocols. For example, there is no manipulation of TCP/UDP
ports. All layer 4 ports are carried transparently as-is. IPREF
does not conflict with NAT. In a common configuration, a NAT
gateway connects to the Internet without any changes. IPREF may
operate in parallel to NAT on the same gateway, or it may operate
on another gateway within the local network 'behind NAT'.
* VPN - IPREF deals mostly with addressing. It does not perform
typical functions of a VPN and it does not replace it. It behaves
differently. A typical VPN makes hosts of a local network appear
as if members of some other local network. Hosts subjected to a
VPN are managed by that other private networks. This involves a
substantial level of trust between the two private networks.
IPREF does not do any of that. Hosts reachable through IPREF are
firmly in their respective private networks and remain managed by
their respective administrators. There may be cases where IPREF
may be deemed sufficient for a particular purpose but in general
IPREF is not a substitute for a VPN. IPREF does not conflict with
VPNs. A VPN might use IPREF to establish a VPN connection.
* Firewall - IPREF is not a firewall. While allocation or lack of
allocation of references has the effect of blocking or allowing
access, blocking policy is best vested with firewalls. IPREF
mappers deal with address rewriting, they are not packet filters.
There is no conflict between firewalls and IPREF. Firewalls might
benefit from IPREF specific features to simplify management and
configuration.
6. IANA Considerations
This memo includes no requests to IANA.
7. Security Considerations
This document should not affect the security of the Internet.
Documents describing particular pieces of IPREF might. Proper
security consideration statements would be included in those
documents.
8. References
8.1. Normative References
[RFC791] Postel, J., "Internet Protocol", RFC 791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
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[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <https://www.rfc-editor.org/info/rfc1035>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
8.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
Author's Address
Waldemar Augustyn (editor)
Email: waldemar@wdmsys.com
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