Network Working Group N. Matsuhira
Internet-Draft Fujitsu Limited
Intended status: Informational K. Horiba
Expires: November 11, 2012 Y. Ueno
O. Nakamura
Keio Univ.
May 10, 2012
SA46T Address Translator
draft-matsuhira-sa46t-at-00
Abstract
This document specifies SA46T Address Translator (SA46T-AT)
specification. SA46T-AT enable access to IPv4 only host from IPv6
host. IPv4 host is identified as SA46T global address in IPv6
address space. The address assigned to IPv4 host may be global IPv4
address or private IPv4 address. SA46T-AT does not support access to
IPv6 host from IPv4 only host.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo
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provisions of BCP 78 and BCP 79.
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Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SA46T-AT Architecture . . . . . . . . . . . . . . . . . . . . . 3
2.1. SA46T address . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Mapping IPv4 address and IPv6 address . . . . . . . . . . . 4
2.3. AddressTranslation Table . . . . . . . . . . . . . . . . . 4
2.4. DNS mapping of IPv4 only host . . . . . . . . . . . . . . . 4
3. Sample Configuration . . . . . . . . . . . . . . . . . . . . . 4
3.1. SA46T address and IPv4 network plane ID . . . . . . . . . . 4
3.2. Network Configuration . . . . . . . . . . . . . . . . . . . 5
3.3. Routing . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Processing of SA46T-AT . . . . . . . . . . . . . . . . . . . . 6
4.1. Configuration of SA46T-AT . . . . . . . . . . . . . . . . . 6
4.2. Processing from IPv6 to IPv4 . . . . . . . . . . . . . . . 7
4.3. Processing from IPv6 to IPv4 . . . . . . . . . . . . . . . 7
4.4. Other processing . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
The IPv4 address exhaution already became the real.
In 03-Feb-2011, IANA Unallocated Address Pool was exhausted. And in
19-Apr-2011, APNIC unallocated address pool was exhaused. Other
RIRs, unallocated address pool does not exhaused now, however, it
should be a matter of time. For more details, please refer to IPv4
address report , http://www.potaroo.net/tools/ipv4/.
After IPv4 address running out, IPv6 only network service should be
provided. SA46T [I-D.matsuhira-sa46t-spec] provide IPv4 network
service over IPv6 only network environments. And SA46T grobal
address [I-D.matsuhira-sa46t-gaddr]is proposed for The Internet
scale.
On the other side, to maintain the continuance of service by the
server, shifting to IPv6 is also needed. However, there should be a
service which has difficulty to quick shift to the IPv6. That mean
IPv4 service continuance is still important.
There are two approaches which use IPv4 address effectively. One is
address sharing approach such as Address plus port (A+P) Approach
[RFC6346], and the other is address re-use approach such as IPv4
private address [RFC1918].
SA46T-AS [I-D.matsuhira-sa46t-as] is also address sharing approch.
SA46T-AT is equivalent to address reuse approach.
2. SA46T-AT Architecture
2.1. SA46T address
Figure 1 show SA46T address[I-D.matsuhira-sa46t-spec]. SA46T global
address is same format with SA46T address, and "SA46T address prefix"
part should allocate for this usage. And "IPv4 network plane ID"
value MUST unique.
| 96 - m bits | m bits | 32 bits |
+-----------------------+--------------------------+--------------+
| SA46T address prefix | IPv4 network plane ID | IPv4 address |
+-----------------------+--------------------------+--------------+
Figure 1
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2.2. Mapping IPv4 address and IPv6 address
SA46T address contain IPv4 address. Mapping IPv4 host address to
IPv6 address space is already done with SA46T address. Address
translation for IPv4 address is same as resolving SA46T address.
IPv6 host address and corresponding IPv4 address should manage.
2.3. AddressTranslation Table
Figure 2 shows translation table for SA46T-AT. Translation table
contain three value, IPv6 adddress ot IPv6 host, mapped IPv4 address
for the IPv6 host, and extry expire timer for remove the entry.
+----------------------+----------------------+--------------------+
| Address of IPv6 host | mapped IPv4 address | entry expire timer |
| | for IPv6 host | |
+----------------------+----------------------+--------------------+
| : | : | : |
~ : ~ : ~ : ~
| : | : | : |
+----------------------+----------------------+--------------------+
| Address of IPv6 host | mapped IPv4 address | entry expire timer |
| | for IPv6 host | |
+----------------------+----------------------+--------------------+
Figure 2
2.4. DNS mapping of IPv4 only host
In the Domain Name System, hostnames are mapped to IPv6 addresses by
AAAA resource records. SA46T address can be mapped to IPv4 only host
name.
3. Sample Configuration
3.1. SA46T address and IPv4 network plane ID
In this example, SA46T address prefix length is 64bits, and IPv4
network plane ID length is 32 bits. SA46T prefix value is 2001:0DB8:
0:46, and IPv4 network plane ID value is 0:46. Figure 3 shows these
value.
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| 64 bits | 32 bits | 32 bits |
+-----------------------+--------------------------+--------------+
| SA46T address prefix | IPv4 network plane ID | IPv4 address |
| (2001:0DB8:0:46) | (0:46) | |
+-----------------------+--------------------------+--------------+
Figure 3
3.2. Network Configuration
Figure 4 shows sample network configuration. IPv6 network have 2001:
0DB8:1:0/64 network prefix and IPv4 network have 10.0.0.0/24 network
prefix.
+----------------+
| IPv6 host |
| 2001:0DB8:1.0::10
+----------------+
|
| 2001:0DB8:1:0/64
|
+----------------+
| 2001:0DB8:1:0::1
| |
| SA46T-AT |
| address pool for IPv6 host mapping
| 192.168.0.0/24
| |
| 10.0.0.1
+----------------+
|
| 10.0.0.0/24
|
+----------------+
| IPv4 only host |
| |
| ipv4onlyhost10.example.com
| 10.0.0.10 |
| (2001:0DB8:0:46:0:64:10.0.0.10)
| |
+----------------+
Figure 4
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IPv6 host address is 2001:0DB8:1:0::10. IPv4 only host address is
10.0.0.10. SA46T address for IPv4 only host is 2001:0DB8:0:46:0:64:
10.0.0.10. FQDN of IPv4 only host is ipv6onlyhost10.example.com.
Figure 5 shows DNS entry in IPv4 address space, and Figure 6 shows
DNS entry in IPv6 space.
ipv6onlyhost10.example.com IN A 10.0.0.10
Figure 5
ipv6onlyhost10.example.com IN AAAA 2001:0DB8:0:46:0:64:10.0.0.10
Figure 6
The address of IPv4 interface of SA46T-AT is 10.0.0.1, and the
address of IPv6 interface of SA46T-AT is 2001:0DB8:1:0::1. SA46T-AT
have also IPv4 address pool for IPv6 host mapping. This example, the
IPv4 address pool is 192.168.0.0/24.
The default router for IPv4 only host is SA46T-AT's IPv4 interface
address, 10.0.0.1.
3.3. Routing
SA46T-AT advertise SA46T address prefix for IPv4 only host, 2001:
0DB8:0:46:0:64:10.0.0.0/120. This manner is same as SA46T.
4. Processing of SA46T-AT
4.1. Configuration of SA46T-AT
1. SA46T address prefix for route advertisement (2001:0DB8:0:46:0:
64:10.0.0.0/120)
2. IPv4 address pool for IPv6 hosts
3. entry expire default time (TBD)
SA46T address contain IPv4 network plane ID, so SA46T-AT know IPv4
network plane ID from SA46T address prefix.
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4.2. Processing from IPv6 to IPv4
1. SA46T-AT examine the exists of the entry for IPv6 host, that is
source IPv6 address of IPv6 packet.
2. If there is no entry, get IPv4 address for mapping of IPv6 host
from IPv4 address pool, and make entry to the translation table.
3. IF there is the entry, resove mapped IPv4 address for IPv6 host.
4. Make IPv4 header, source address is mapped IPv4 address, and
destination address is from SA46T address.
5. Translate IPv6 packet to IPv4 packet, and send it, and reset
entry expire timer.
The example addess translation table is shown in Figure 7. In this
example, IPv6 host address is mapped to 192.168.0.200.
+----------------------+----------------------+--------------------+
| Address of IPv6 host | mapped IPv4 address | entry expire timer |
| | for IPv6 host | |
+----------------------+----------------------+--------------------+
| 2001:0DB8:1.0::10 | 192.168.0.200 | TBD |
+----------------------+----------------------+--------------------+
Figure 7
4.3. Processing from IPv6 to IPv4
1. Search address translation table with key destination IPv4
address, and resolve corrensponding IPv6 address.
2. Resolve source IPv6 address from sourve IPv4 address with SA46T
address generation rule.
3. Translate IPv4 packet to IPv6 packet, and sent it, and reset
extry expire timer.
4.4. Other processing
1. Remove the entry of address translation table if expire.
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5. IANA Considerations
This document may requests IANA to assign IPv6 prefix for SA46T
Global address.
6. Security Considerations
Security consideration does not discussed in this memo, at this time.
7. Acknowledgements
8. References
8.1. Normative References
[I-D.matsuhira-sa46t-as]
Matsuhira, N., "Stateless Automatic IPv4 over IPv6
Tunneling with IPv4 Address Sharing",
draft-matsuhira-sa46t-as-03 (work in progress),
April 2012.
[I-D.matsuhira-sa46t-gaddr]
Matsuhira, N., "Stateless Automatic IPv4 over IPv6
Encapsulation / Decapsulation Technology: Global SA46T
Address Format", draft-matsuhira-sa46t-gaddr-04 (work in
progress), January 2012.
[I-D.matsuhira-sa46t-spec]
Matsuhira, N., "Stateless Automatic IPv4 over IPv6
Encapsulation / Decapsulation Technology: Specification",
draft-matsuhira-sa46t-spec-04 (work in progress),
January 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, February 1996.
[RFC3849] Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
Reserved for Documentation", RFC 3849, July 2004.
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[RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the
IPv4 Address Shortage", RFC 6346, August 2011.
Authors' Addresses
Naoki Matsuhira
Fujitsu Limited
1-1, Kamikodanaka 4-chome, Nakahara-ku
Kawasaki, 211-8588
Japan
Phone: +81-44-754-3466
Fax:
Email: matsuhira@jp.fujitsu.com
Katsuhiro Horiba
Keio Univ.
5322 Endo
Fujisawa, 252-8520
Japan
Phone:
Fax:
Email: qoo@sfc.wide.ad.jp
URI:
Yukito Ueno
Keio Univ.
5322 Endo
Fujisawa, 252-8520
Japan
Phone:
Fax:
Email: eden@sfc.wide.ad.jp
URI:
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Osamu Nakamura
Keio Univ.
5322 Endo
Fujisawa, 252-8520
Japan
Phone:
Fax:
Email: osamu@wide.ad.jp
URI:
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