Internet DRAFT - draft-matsuhira-sa46t-pr-spec
draft-matsuhira-sa46t-pr-spec
Network Working Group N. Matsuhira
Internet-Draft Fujitsu Limited
Intended status: Standards Track July 23, 2015
Expires: January 24, 2016
SA46T Prefix Resolution (SA46T-PR)
draft-matsuhira-sa46t-pr-spec-05
Abstract
This document specifies SA46T Prefix Resolution (SA46T-PR)
specification. SA46T-PR is almost same as SA46T, however method of
generation of outer IPv6 address is different. SA46T is backbone
network based approach, however SA46T-PR is stub network based
approch.
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
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 24, 2016.
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document authors. All rights reserved.
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Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Basic Network Configuration . . . . . . . . . . . . . . . . . 3
3. Basic Function of SA46T-PR . . . . . . . . . . . . . . . . . . 4
3.1. IPv4 over IPv6 Encapsulation / Decapsulation . . . . . . . 4
3.2. SA46T-PR Address Format . . . . . . . . . . . . . . . . . 5
3.3. Resolving SA46T-PR address . . . . . . . . . . . . . . . . 6
4. Mode of SA46T-PR . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Router mode . . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Host mode . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Sample configuration . . . . . . . . . . . . . . . . . . . . . 7
6. Comparison with SA46T . . . . . . . . . . . . . . . . . . . . 9
6.1. difference with SA46T . . . . . . . . . . . . . . . . . . 9
6.2. Compatibility with SA46T . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
This document provide SA46T Prefix Resolution (SA46T-PR)
specification.
The basic strategy for IPv6 deployment is dual stack. However,
because of exhaustion of IPv4 address, there will be no IPv4
addresses for configuring dual stack in near future. That means
there will be IPv6 only networks automatically.
However, there are many IPv4 only networks still exist and those
seems continuous use in near future. That means methods continuous
use of IPv4 network over IPv6 only network will be required.
SA46T [I-D.draft-matsuhira-sa46t-spec] provide such methods. In
addition, SA46T-PR also provide such methots. SA46T is backbone
network based approach, on the other hand, SA46T-PR is stub network
based approach.
2. Basic Network Configuration
Figure 1 shows network configuration with SA46T-PR. The network
consists of three parts, backbone network, stub network, and
SA46T-PR.
Backbone network can be operated with IPv6 only. Stub network has
three cases, IPv4 only, Dual Stack (both IPv4 and IPv6), and IPv6
only.
SA46T connects backbone network and stub network in case IPv4 still
works in that stub network. If stub network is IPv6 only, SA46T-PR
is not needed.
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/---------------------------------------------------\
| |
| Backbone Network |
| (IPv6 only) |
| |
\---------------------------------------------------/
| | |
| | |
| | |
+----------+ +----------+ |
/-| SA46T-PR |-\ /-| SA46T-PR |-\ /--------------\
| +----------+ | | +----------+ | | |
| | | | | |
| Stub Network | | Stub Network | | Stub Network |
| (IPv4 only) | | (Dual Stack) | | (IPv6 only) |
| | | | | |
\--------------/ \--------------/ \--------------/
Figure 1
3. Basic Function of SA46T-PR
SA46T-PR has mainly two function. One is IPv4 over IPv6
Encapsulation / Decapsulation, and another is generate a table where
IPv4 stub network belong to IPv6 network.
3.1. IPv4 over IPv6 Encapsulation / Decapsulation
SA46T-PR excapsulates IPv4 packet to IPv6 from stub network to
backbone network, and decapsulates IPv6 packet to IPv4 from backbone
network to stub network. Figure 2 shows packet format on both
backbone network and stub network.
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+--------+------------+ +----------+--------+------------+
|IPv4 Hdr| Data | --> | IPv6 Hdr |IPv4 Hdr| Data |
+--------+------------+ +----------+--------+------------+
+--------+------------+ +----------+--------+------------+
|IPv4 Hdr| Data | <-- | IPv6 Hdr |IPv4 Hdr| Data |
+--------+------------+ +----------+--------+------------+
/-------------------\ +----------+ /-----------------------------\
| Stub Network |--| SA46T-PR |--| Backbone Network |
| (IPv4) | +----------+ | (IPv6 only) |
\-------------------/ \-----------------------------/
Figure 2
3.2. SA46T-PR Address Format
SA46T-PR address is a IPv6 address used in outer IPv6 header which
encapsulate IPv4 packet by SA46T-PR. Figure 3 shows SA46T-PR address
format.
| 96 - m bits | m bits | 32 bits |
+--------------------------+------------------------+--------------+
| SA46T-PR address prefix | IPv4 network plane ID | IPv4 address |
+--------------------------+------------------------+--------------+
Figure 3
SA46T address consists of three parts as follows.
SA46T-PR address prefix
SA46T-PR address prefix is the IPv6 network prefix of stub network
which contain IPv4 network of the IPv4 network plane.
IPv4 network plane ID
IPv4 network plane ID is an identifier of IPv4 network stack over
IPv6 backbone network.
IPv4 address
IPv4 address in inner IPv4 packet.
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3.3. Resolving SA46T-PR address
SA46T-PR resolve SA46T-PR address using SA46T Prefix Resolution Table
(SA46T-PR Table). SA46T-PR generate SA46T-PR address resolving
SA46T-PR prefix from IPv4 network plane ID and IPv4 address.
FigureFigure 4 show this processing.
| 96 - m bits | m bits | 32 bits |
+--------------------------+------------------------+--------------+
| SA46T-PR address prefix | IPv4 network plane ID | IPv4 address |
+--------------------------+------------------------+--------------+
\--------------------------/\--------------------------------------/
^ |
| |
| v
+------------------------------------------------------------------+
| |
| SA46T Prefix Resolution Table (SA46T-PR Table) |
| |
+------------------------------------------------------------------+
Figure 4
Figure Figure 5show SA46T-PR Table. This table consists four parts,
IPv4 network plane ID, IPv4 address, netmask, and SA46T-PR address
prefix.
+---------------------+------------+-------++-----------------------+
|IPv4 network plane ID|IPv4 address|netmask||SA46T-PR address prefix|
+---------------------+------------+-------++-----------------------+
|IPv4 network plane ID|IPv4 address|netmask||SA46T-PR address prefix|
+---------------------+------------+-------++-----------------------+
|IPv4 network plane ID|IPv4 address|netmask||SA46T-PR address prefix|
+---------------------+------------+-------++-----------------------+
|IPv4 network plane ID|IPv4 address|netmask||SA46T-PR address prefix|
+---------------------+------------+-------++-----------------------+
: : :
+---------------------+------------+-------++-----------------------+
|IPv4 network plane ID|IPv4 address|netmask||SA46T-PR address prefix|
+---------------------+------------+-------++-----------------------+
Figure 5
SA46T-PR configured IPv4 network plane ID, so SA46T-PR know IPv4
network plane ID value the interface belongs.
Resolving destination address, SA46T-PR use pre-configured IPv4
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network plane ID valude, and destination address of IPv4 packets, and
serch the SA46T-PR table. SA46T-PR table return the SA46T-PR address
prefix value correspoiding IPv4 network plane ID and IPv4 destination
address. Then SA46T-PR generate whole SA46T-PR address.
Resolving source address, SA46T-PR already know IPv4 network plane ID
value and IPv6 address prefix as SA46T-PR prefix. So, searching the
SA46T-PR table does not require for resolving source address.
4. Mode of SA46T-PR
SA46T-PR has two working mode, one is router mode, another is host
mode.
4.1. Router mode
In router mode, SA46T-PR act as a IPv6 router. SA46T-PR occupy IPv6
subnet, and SA46T-PR advertise route for SA46T-PR.
4.2. Host mode
In host mode, SA46T-PR act as a IPv6 host. SA46T-PR share IPv4
subnet, that mean, SA46T-PR and IPv6 hosts exists on same IPv6
subnet. SA46T-PR do proxy NDP function for IPv4 host.
5. Sample configuration
Figure Figure 6shows sample confiuration of SA46T-PR. In this
example, there are three IPv4 stub network with the same IPv4 network
plane.
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/------------\ /--------------------------------------/
| | | Stub Network #1 |
| | | 2001:0db8:0:1::/64 |
| | | +--------+ /----------------------\ |
| |--| |SA46T-PR|--|10.1.1.0/24(plane 1) | |
| | | +--------+ | | |
| | | \----------------------/ |
| <--[2001:0db8:0:1::/64] |
| | /--------------------------------------/
| |
| | /--------------------------------------/
| | | Stub Network #2 |
| | | 2001:0db8:0:2::/64 |
| Backbone | | +--------+ /----------------------\ |
| Network |--| |SA46T-PR|--|10.1.2.0/24(plane 1) | |
| | | +--------+ | | |
| | | \----------------------/ |
| <--[2001:0db8:0:2::/64] |
| | /--------------------------------------/
| |
| | /--------------------------------------/
| | | Stub Network #3 |
| | | 2001:0db8:0:3::/64 |
| | | +--------+ /----------------------\ |
| |--| |SA46T-PR|--|10.1.3.0/24(plane 1) | |
| | | +--------+ | | |
| | | \----------------------/ |
| <--[2001:0db8:0:3::/64] |
| | /--------------------------------------/
| |
\------------/
Figure 6
Figure Figure 7 shows SA46T-PR table for sample network.
+---------------------+------------+-------++-----------------------+
|IPv4 network plane ID|IPv4 address|netmask||SA46T-PR address prefix|
+---------------------+------------+-------++-----------------------+
| 1 | 10.1.1.0 | /120 || 2001:0db8:0:1 |
| 1 | 10.1.2.0 | /120 || 2001:0db8:0:2 |
| 1 | 10.1.3.0 | /120 || 2001:0db8:0:3 |
+---------------------+------------+-------++-----------------------+
Figure 7
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6. Comparison with SA46T
SA46T is backbone network based approach, and SA46T-PR is stub
network based approach.
6.1. difference with SA46T
SA46T require route advertisement of SA46T prefix, so additional
route are require, however configuration is few. On the other hand,
SA46T-PR does not require additional route, however SA46T-PR table is
require.
There are such trade-off between SA46T and SA46T-PR.
6.2. Compatibility with SA46T
If configure SA46t-PR table with default prefix as SA46T prefix,
SA46T-PR acts as SA46T. In this case, netmask value of SA46T-PR table
is /0, that mean any IPv4 network plane ID and IPv4 address pair
match this entry.
7. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
8. Security Considerations
Security Considerations does not discussed in this memo.
9. Acknowledgements
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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10.2. Informative References
[I-D.draft-matsuhira-sa46t-spec]
Matsuhira, N., "Stateless Automatic IPv4 over IPv6
Encapsulation / Decapsulation Technology: Specification",
January 2014.
Author's Address
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
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