Network Working Group N. Matsuhira
Internet-Draft Fujitsu Limited
Intended status: Experimental October 17, 2010
Expires: April 20, 2011
Stateless Automatic IPv4 over IPv6 Tunneling with IPv4 Address Sharing
draft-matsuhira-sa46t-as-00
Abstract
This document specifies Stateless Automatic IPv4 over IPv6 Tunneling
with IPv4 Address Sharing (SA46T-AS) base specification. SA46T-AS is
basically the same technology with SA46T, however that have IPv4
address sharing capability. SA46T-SA is gateway technology, not
protocol.
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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This Internet-Draft will expire on April 20, 2011.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Architecture of SA46T-AS . . . . . . . . . . . . . . . . . . . 3
3. SA46T-AS address format . . . . . . . . . . . . . . . . . . . . 5
4. Using SA46T-AS in client server environments . . . . . . . . . 5
4.1. Client environments . . . . . . . . . . . . . . . . . . . . 5
4.2. Server environments . . . . . . . . . . . . . . . . . . . . 6
5. Characteristic . . . . . . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . . 8
8.2. References . . . . . . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
This document provides Stateless Automatic IPv4 over IPv6 Tunneling
with IPv4 Address Sharing (SA46T-AS) base specification.
SA46T-AS is basically the same technology with
SA46T[I-D.draft-matsuhira-sa46t-spec] , however that have IPv4
address sharing capability.
The basic architecture of the SA46T-AS is the same with SA46T, so
SA46T-AS can provide all of SA46T function, such as making bachbone
network IPv6 only , or provide many IPv4 network planes over single
IPv6 backbone network.
SA46T-AS add IPv4 address sharing function to SA46T. So, SA46T-AS
enable many host to share single IPv4 global address.
SA46T is gateway technology, not protocol.
2. Architecture of SA46T-AS
Figure 1 shows SA46T address architecture. SA46T map IPv4 address to
SA46T address keeping locator - identifier relation. The n bits
identifier part of IPv4 address and n bits identifier part of IPv6
address is the same value, and the 32-n bits locator part in IPv4
address and 128 - n bits locator part in IPv6 address is the same
meaning. So, the meaning of routing information is the same between
IPv4 space and IPv6 space.
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|<------------------------ 128 bits ----------------------------->|
|<-------------------- 96 bits ------------------->|<-- 32 bits ->|
| : |
| +-------:------+
| | IPv4 address |
| +-------:------+
| |<-Loc->:<-ID->|
| | 32-n : n |
| | bits : bits |
| | : |
| | : |
| | : |
| 96 - m bits | m bits | 32 bits |
+-----------------------+--------------------------+-------:------+
| SA46T address prefix | IPv4 network plane ID | IPv4 address |
+-----------------------+--------------------------+-------:------+
|<------------- Locator (128 - n bits ) ------------------>:<-ID->|
| : n |
| : bits |
Figure 1
Figure 2 shows SA46T-AS address architecture. SA46T-AS address
consists four parts, SA46T-AS prefix, IPv4 network plane ID, IPv4
address, and Port number. That mean SA46T-AS address consists SA46T
address and port number.
| | | | |
| 80 - m bits | m bits | 32 bits | 16 bits |
+----------------------+----------------+----------------+----:----+
| SA46T-AS prefix | IPv4 network | IPv4 address | port |
| | plane ID | | number |
+----------------------+----------------+----------------+----:----+
|<--------------- Locator (128 -n bits )-------------------->:<-->|
| : ID |
| : (n bits)
Figure 2
In SA46T, boundary of locator and identifier is in IPv4 address part,
however in SA46T-AS, boundary of locator and identifier is in port
number part, that mean, SA46T-AS use upper part of port number as
locator, and lower part of port number as identifier.
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3. SA46T-AS address format
Figure 3 show a example of SA46T-AS address format. In this example,
16bits IPv4 network plane ID is used, that provide 65535 IPv4 network
plane.
| 3 | 45bits | 16bits | 16 bits| 32bits | 16 bits |
+---+---------------------+---------+---------+------------+---------+
|001|Global routing prefix|subnet id| plane ID|IPv4 address| Port # |
+---+---------------------+---------+----------------------+---------+
<---SA46T address prefix----------->
Figure 3
4. Using SA46T-AS in client server environments
4.1. Client environments
Figure 4 shows a example of SA46T-AS usage in client environments.
In this document, NAPT is IPv4 - IPv4 Netowrk address and port number
translator. Coopetation with NAPT, SA46T-AS provide IPv4 address
sharing with different users.
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+--------------+
| | +---------+ +--------+ +---------+
| +----|SA46T-AS |--| NAPT |--+--| Clients |
| | +---------+ +--------+ | +---------+
| | | +---------+
| | +--| Clients |
| Backbone | | +---------+
| | :
| | | +---------+
| Network | +--| Clients |
| | +---------+
| |
| | +---------+ +--------+ +---------+
| +----|SA46T-AS |--| NAPT |--+--| Clients |
| | +---------+ +--------+ | +---------+
| | | +---------+
| | +--| Clients |
| | | +---------+
| | :
| | | +---------+
| | +--| Clients |
| | +---------+
: : : : :
| | +---------+ +--------+ +---------+
| +----|SA46T-AS |--| NAPT |--+--| Clients |
| | +---------+ +--------+ | +---------+
| | | +---------+
| | +--| Clients |
| | | +---------+
| | :
| | | +---------+
| | +--| Clients |
| | +---------+
+--------------+
Figure 4
4.2. Server environments
Figure 5 shows an example of SA46T-AS usage in server environments.
In this example, server terminate SA46T-AS tunnel. This case, Server
require at least one port number per server, that mean, 128bits host
route advertise for server access via IPv4. This case, full access
is provided via IPv6.
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+--------------+
| | +------------+
| +----|Server with |
| | |SA46T-AS |
| Backbone | |function |
| | +------------+
| | +------------+
| Network +----|Server with |
| | |SA46T-AS |
| | |function |
| | +------------+
: : :
| | +------------+
| +----|Server with |
| | |SA46T-AS |
| | |function |
| | +------------+
+--------------+
Figure 5
5. Characteristic
SA46T has following useful characteristics.
o Reduce backbone network operation cost with IPv6 single stack ( at
least less than Dual Stack)
o Can allocate IPv4 address to stub networks, which used in backbone
network before installing SA46T
o Less configuration
o No need for special protocol
o No dependent Layer 2 network
o Can Stack IPv4 Private networks
o Easy stop IPv4 operation in stub network for future ( just remove
SA46T)
o Provide redundancy
Moreover, SA46T-AS add following characteristsics to SA46T.
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o Provide IPv4 address sharig function
6. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
7. Security Considerations
SA46T-AS use automatic tunneling technologies. Security
consideration related tunneling technologies are discussed in
RFC2893[RFC2893], RFC2267[RFC2267], etc.
8. References
8.1. Normative References
[I-D.draft-matsuhira-sa46t-spec]
Matsuhira, N., "Stateless Automatic IPv4 over IPv6
Tunneling: Specification".
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. References
[RFC2267] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", RFC 2267, January 1998.
[RFC2893] Gilligan, R. and E. Nordmark, "Transition Mechanisms for
IPv6 Hosts and Routers", RFC 2893, August 2000.
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Author's Address
Naoki Matsuhira
Fujitsu Limited
17-25, Shinkamata 1-chome, Ota-ku
Tokyo, 144-8588
Japan
Phone: +81-3-6424-6270
Fax:
Email: matsuhira@jp.fujitsu.com
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