Internet Engineering Task Force G. Chen
Internet-Draft B. Zhou
Intended status: Informational China Mobile
Expires: January 7, 2010 July 6, 2009
Host-based Translation Problem Statement
draft-chen-host-ipv6-ps-00
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Internet-Draft Host-IPv6-PS July 2009
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Abstract
When operators start to customize user terminals, host-based IPv6
translation will be feasible. Host-based translation should overcome
single-point failure problems and support various connections between
two IP families networks simultaneously. In addition, legacy IPv4
applications should not be modified. This document will discuss
host-based translation applicable scenarios and corresponding issues.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Host-based translation scenarios and problems . . . . . . . . . 3
2.1. Host-based translation scenarios . . . . . . . . . . . . . 3
2.2. Problems . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. Normative References . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5
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1. Introduction
Current network is mostly depending on IPv4. And, several
sophisticated technologies have been proposed to prolong the IPv4
lifetime, such as NAPT, A+P[A+P] . Although these solutions could
alleviate IPv4 depletion pressure in a short term, the transition
from IPv4 to IPv6 is still a steady trend of network development.
Technical solutions of IPv6 transition could be divided into three
categories, namely dual-stack, tunneling and translation technology.
Dual-stack hosts can communicate with both the IPv4 and IPv6 hosts,
but it can not help to resolve the IPv4 address exhaustion problems.
The tunneling technology can connect IPv4 networks across IPv6-only
networks and IPv6 networks across IPv4-only networks, thus one IP
family communication is transparent with another IP family.
The translation technology can help the communications between two
address families. With regard to whether deploy translator on hosts
or networks, the majority solutions would like to choose the latter
since modifications on a numerous hosts were treated as not easy
works. However, host-based translation schemes would progress more
easily in recent time, since more and more operators start to
customize hosts for their subscribers.
In this document, host-based translation scenarios and underlying
problems have been described.
2. Host-based translation scenarios and problems
2.1. Host-based translation scenarios
Figure 1 shows host-based translation scenarios. Translator modules
have been deployed on H1 and H3 located in IPv6 only network. And,
both conventional IPv4 applications and IPv6 applications have been
installed. H2 is legacy IPv4 host located in IPv4 site.
With regard to this scenario, H1 and H3 might maintain following
service connections simultaneously.
o case 1: H1 and H4 initiate a service call with H2 using a IPv4
application
o case 2: H1 initiates a service all with the IPv6 application of H3
using a IPv4 application
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o case 3: H3 initiates a service call with H2 using a IPv6
application
o case 4: H1 initiates a service call with the IPv4 application of
H3 using a IPv4 application
+-----------------------------+ +--------------------+
|IPv6 site 4/6 | | IPv4 site |
| +--------+ | | |
| | H1 | | | |
| +--------+ | | |
| | | | |
| 4/6 +--------+ | | |
|+-------+ | Access | +--------+ |+----------+ +----+|
|| H3 |--| Router |-- | NAT |---|| Internet |--| H2 ||
|+-------+ +--------+ +--------+ |+----------+ +----+|
| | | | | 4 |
| +--------+ | | +--------+ |
| | DNS1 | | | | DNS2 | |
| +--------+ | | +--------+ |
| AAAA | | A |
+-----------------------------+ +--------------------+
Figure 1
2.2. Problems
From individual case point-of-view, dual-stack-lite[DS-Lite] can
support case 1, and BIA [RFC3338] or BIS [RFC2767] can support the
case 2, and NAT64[NAT64] can support case 3. There are no solutions
to perform case 4.
According to the analysis, According to the analysis, existing
solution can!_t satisfy the demands of maintaining above all
potential communications in the 4/6 host at one time. Furthermore,
following problems should be considered.
o It is hard to modify numerous conventional IPv4 applications, when
the hosts only have an IPv6 connection
o The hosts located in IPv6 site usually do not initiate query to
DNS4 server, where IPv4 peer record is stored
o The hosts usually do not identify peer application type, thus
translation handling can not be performed correctly
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3. IANA Considerations
This memo includes no request to IANA.
4. Security Considerations
It needs to be further identified.
5. Normative References
[A+P] Bush, R., "The A+P Approach to the IPv4 Address Shortage",
draft-ymbk-aplusp-03 (work in progress), March 2009.
[DS-Lite] Durand, A., "Dual-stack lite broadband deployments post
IPv4 exhaustion", draft-ietf-softwire-dual-stack-lite-00
(work in progress), March 2009.
[NAT64] Bagnulo, M., "NAT64: Network Address and Protocol
Translation from IPv6 Clients to IPv4 Servers",
draft-bagnulo-behave-nat64-03.txt (work in progress),
March 2009.
[RFC2767] Tsuchiya, K., HIGUCHI, H., and Y. Atarashi, "Dual Stack
Hosts using the "Bump-In-the-Stack" Technique (BIS)",
RFC 2767, February 2000.
[RFC3338] Lee, S., Shin, M-K., Kim, Y-J., Nordmark, E., and A.
Durand, "Dual Stack Hosts Using "Bump-in-the-API" (BIA)",
RFC 3338, October 2002.
Authors' Addresses
Gang Chen
China Mobile
53A,Xibianmennei Ave.,
Xuanwu District,
Beijing 100053
China
Email: phdgang@gmail.com
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Bo Zhou
China Mobile
53A,Xibianmennei Ave.,
Xuanwu District,
Beijing 100053
China
Email: zhouboyj@chinamobile.com
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