Network Working Group Y. Cui
Internet-Draft M. Xu
Intended status: Standards Track S. Wang
Expires: January 8, 2010 J. Wu
X. Li
Tsinghua University
C. Metz
Cisco Systems, Inc.
July 7, 2009
IPv4/IPv6 Coexistence Framework (PET)
draft-cui-softwire-pet-00
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. This document may contain material
from IETF Documents or IETF Contributions published or made publicly
available before November 10, 2008. The person(s) controlling the
copyright in some of this material may not have granted the IETF
Trust the right to allow modifications of such material outside the
IETF Standards Process. Without obtaining an adequate license from
the person(s) controlling the copyright in such materials, this
document may not be modified outside the IETF Standards Process, and
derivative works of it may not be created outside the IETF Standards
Process, except to format it for publication as an RFC or to
translate it into languages other than English.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 8, 2010.
Copyright Notice
Cui, et al. Expires January 8, 2010 [Page 1]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Cui, et al. Expires January 8, 2010 [Page 2]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
Abstract
IPv6 offers significant advantages over IPv4. However IPv4 and IPv6
protocols are expected to coexist during a long period. Currently,
there are many IPv4/IPv6 transition/coexistence technologies, which
can be generally devided into two kinds: translation and tunneling.
In some typical transition scenarios, both tunneling and translation
are needed. However, either translation or tunneling has limitation
and application scope. In addition to the IP versions of source
networks and destination networks, the IP version of transport
network (the middle part along end-to-end path) also plays an
important role during IPv4/IPv6 transition/coexistence.
Therefore, we need to decide which transition methods should be used
in different typical transition scenarios and how transition and
tunneling collaborate for solving transition/coexistence problems.
This draft presents an IPv4-IPv6 transition/coexistence framework
named PET (short for Prefixing, Encapsulation and Translation), which
is a network side solution. PET includes fundamental elements needed
in transition scenarios, which provides the flexibility for network
operators to decide the proper transition technology. In addition,
this draft also addresses how to deploy PETs and analyze the
advantages and disadvantages of typical transition technologies that
PET may adopt.
Cui, et al. Expires January 8, 2010 [Page 3]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Fundamental requirements of IPv4-IPv6 transition methods . . . 7
4. Descriptions of PET . . . . . . . . . . . . . . . . . . . . . 8
5. PET Framework . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. IPv4->IPv6->IPv4 . . . . . . . . . . . . . . . . . . . . . 10
5.2. IPv4->IPv6->IPv6 . . . . . . . . . . . . . . . . . . . . . 11
5.3. IPv6->IPv6->IPv4 . . . . . . . . . . . . . . . . . . . . . 13
5.4. IPv6->IPv4->IPv6 . . . . . . . . . . . . . . . . . . . . . 14
5.5. IPv4->IPv4->IPv6 . . . . . . . . . . . . . . . . . . . . . 14
5.6. IPv6->IPv4->IPv6 . . . . . . . . . . . . . . . . . . . . . 15
6. Implementation issues . . . . . . . . . . . . . . . . . . . . 16
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.1. Normative References . . . . . . . . . . . . . . . . . . . 18
8.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
Cui, et al. Expires January 8, 2010 [Page 4]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
1. Introduction
Recently more and more IPv6 networks have been deployed, especially
IPv6 backbone networks, while the existing IPv4 networks still carry
the major network traffic and hold the major network services and
applications, though facing serious address space problem and other
problems. It has been agreed that IPv4 and IPv6 networks will co-
exist for a long term. This leads to the need of IPv4-IPv6
transition methods.
There are many methods for IPv4-IPv6 transition, which can be roughly
classified into two groups: translation and tunneling. Translation
is a technology that translates semantic between IPv4 and IPv6.
There are many translation methods, such as SIIT [RFC 2765], NAT-PT
[RFC 2766], BIS [RFC 2767], SOCKS64 [RFC 3089], BIA [RFC 3338], IVI
[draft-ietf-xli-behave-ivi-02] and so on. Translation technology can
realize interworking between IPv4 and IPv6 directly, however, it will
lead to information loss.
Tunneling is a technology to encapsulate packets from a different
protocol within the protocol of the route that delivers it to the
target network. There are many tunneling methods, such as IP-in-IP
tunnel [RFC 2893, RFC 4213], GRE tunnel [RFC 1702], 6to4 tunnel [RFC
2893], 6over4 tunnel [RFC 2529], softwire transition technology [RFC
5565] and so on. Tunneling technology can not realize the
interworking between IPv4 and IPv6 directly. It can only deal with
the scenario where two IPv4 (IPv6) nodes want to communicate with
each other through IPv6 (IPv4) network. However, tunneling
technology has several advantages, besides no information loss, it
can be realized easily by hardware, and does not introduce routing
information into a network with different address family.
In some typical transition scenarios, both tunneling and translation
are needed. However, as described above, either translation or
tunneling has limitation and application scope. In addition, besides
IP version of source, middle and destination network, the network
property (a regular edge network or a backbone) has key impact on
system performance. Therefore, we need to decide which transition
method should be used in some typical transition scenarios and how
transition and tunneling collaborate for solving transition problems.
This draft presents an IPv4-IPv6 transition framework, which is a
network side transition solution. It introduces a toolbox named PET
(short for Prefixing, encapsulation and translation) to solve IPv4-
IPv6 transition. PET includes fundamental elements needed in
transition scenarios, which provides the flexibility for network to
decide the proper transition methods. In addition, this draft also
addresses how to deploy PETs and analyze the advantages and
disadvantages of all transition methods that PET may adopt.
Cui, et al. Expires January 8, 2010 [Page 5]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
2. Terminology
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 [RFC2119].
Cui, et al. Expires January 8, 2010 [Page 6]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
3. Fundamental requirements of IPv4-IPv6 transition methods
There are two main IPv4-IPv6 transition scenarios. One is to connect
several edge networks with the same address family across a transit
core network with another address family; the other scenario is to
make hosts with one address family capable of directly communicating
with hosts with the other address family. We call the first scenario
heterogeneous crossing. The scenario where two IPv4 (IPv6) nodes
want to communicate with each other through IPv6 (IPv4) network
belongs to heterogeneous crossing. We call the second scenario
heterogeneous direct-connection. The scenario where an IPv4 (IPv6)
node wants to directly communicate with an IPv6 (IPv4) node belongs
to heterogeneous direct-connection.
In fact, most IPv4-IPv6 transition scenarios can be viewed as the
combination of heterogeneous crossing and direct-connection. Hence,
the fundamental transition elements needed in heterogeneous crossing
and direct-connection are those needed in most IPv4-IPv6 transition
scenarios.
In heterogeneous crossing scenario, tunneling technology can be used
to transmit IPv4 (IPv6) packets through IPv6 (IPv4) networks. In
addition, through twice translations, IPv4 (IPv6) packets can also be
transmitted through IPv6 (IPv4) networks in heterogeneous crossing
scenario. In heterogeneous direct-connection scenario, when IPv4
(IPv6) nodes want to communicate with IPv6 (IPv4) nodes directly, it
can only use translation technology.
In addition, when adopting tunneling for supporting IPv4/IPv6
interworking, some control operations involved with subnet prefix
should be done beforehand. These operations include prefix
announcement, tunnel endpoint discovery, the selection of tunnel
endpoint and tunnel belonging to the same tunnel endpoint, tunnel
configuration, and so on. Similarly, when adopting translation
method for supporting IPv4/IPv6 interworking, some control operations
involved with subnet prefix also should be done in advance. These
operations include the establishment of address mapping mechanism,
prefix configuration and so on. We call these control operations
involved with subnet prefix prefixing.
In conclusion, there are three fundamental elements needed in IPv4-
IPv6 transition scenarios, i.e. prefixing, encapsulation and
translation. To realize a framework in network side for IPv4/IPv6
translation, this draft introduces a toolbox named PET which includes
the above fundamental elements. The detailed descriptions are given
in section 4.
Cui, et al. Expires January 8, 2010 [Page 7]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
4. Descriptions of PET
PET is a smart transition toolbox supporting IPv4/IPv6 inter-working.
It can deal with the heterogeneous crossing and direct-connection
scenarios. Because all IPv4-IPv6 transition scenarios can be viewed
as the combination of the heterogeneous crossing and direct-
connection, the PET-based transition method is a generic solution for
IPv4/IPv6 transition. PET toolbox has the following functions:
P: representing prefixing. Prefixing includes all transition
operations of control plane involved with subnet prefix.
In detail, in tunneling technology, prefixing includes prefix
announcement, tunnel endpoint discovery, the selection of tunnel
endpoint and tunnel belonging to the same tunnel endpoint, and so on.
For example, in softwire transition technology, the IPv6 prefix and
IPv4 next-hop mapping information should be announced out through
extended MP-BGP (Multi-protocol BGP) signaling beforehand. Based on
this prefixing operation, the automatic 4over6 tunnels can be
established. In translation technology, prefixing includes the
establishment of address mapping mechanism, prefix configuration and
so on. For example, in IVI-based translation scheme, the global IPv6
prefix should be configured in an autonomous domain (AS) beforehand,
to form the global IVI address, thus realizing the stateless
translation.
E: representing encapsulation. E includes all tunneling operations
of data plane, such as encapsulation, decapsulation and maximum
transmission unit (MTU) processing and so on. Through this
operation, packets from IPv6 (IPv4) network are encapsulated on the
PET toolbox and sent across IPv4 (IPv6) backbone to another IPv6
(IPv4) network according to the mappings stored on the PET box.
T: representing translation. It includes all translation operations
of data plane, such as address mapping and protocol translation, MTU
processing.
Address mapping is to map IPv4 addresses to IPv6 addresses, and vice
versa. Based on address mapping, packets can be translated from one
address family to another. IPv4 and IPv6 are not directly
compatible, so programs and systems designed on one standard can not
communicate with those designed to the other. Hence we need protocol
translation. Here, protocol translation includes IP layer
translation and application layer translation. Through protocol
translation, the semantic of IP layer and application layer of an
IPv4 packet is equivalent with that of the translated IPv6 packet and
vice versa. In addition, to implement translation, PET may
collaborate with the domain name system (DNS).
Cui, et al. Expires January 8, 2010 [Page 8]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
The basic idea of our solution is to deploy several PET toolboxes
between backbone network and customer networks. The following
section will discuss how PET deals with different IPv4/IPv6
translation scenarios in detail.
Cui, et al. Expires January 8, 2010 [Page 9]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
5. PET Framework
Figure 1 shows the overall topology of PET framework, which uses PET
boxes between IPv6 backbone and IPv4 customer networks. In this
topology, an IPv6 backbone is connected with several customer
networks including IPv4 backbone, IPv4 virtual private networks
(VPNs), IPv6 network and dual stack networks.
+------------------+
| IPv4 backbone |
| |
+------------------+
| |
| |
+--------+ +--------+
| PET | | PET |
+--| |---| |--+
| +--------+ +--------+ |
| |
+--------+ +--------+ +--------+ +-------+
| IPv4 | | PET | IPv6 backbone | PET | | IPv4 |
|network |___| | | |__|network|
+--------+ +--------+ +--------+ +-------+
| |
| +--------+ +--------+ |
+--| PET |---| PET |--+
| | | |
+--------+ +--------+
| \ / |
| X |
| / \ |
+--------+ +--------+
| IPv6 | | IPv4/ |
| | | IPv6 |
| Network| | Network|
+--------+ +--------+
Figure 1 Topology of PET Framework
For different transition scenarios, PET can provide different
functionalities to ensure the inter-working of IPv4/IPv6 network. We
will analyze how PET works in some typical scenarios in the following
subsections.
5.1. IPv4->IPv6->IPv4
This is the scenario where an IPv4 network wants to talk with another
IPv4 network across IPv6 backbone. There are two methods for PET to
Cui, et al. Expires January 8, 2010 [Page 10]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
handle this scenario. One is translation and the other is tunneling.
If PET adopts translation method, we need twice translations. In
detail, an IPv4 packet need be translated by PET into an IPv6 packet
for being delivered through IPv6 backbone. When this packet arrives
at another PET, it will be translated into an IPv4 packet again for
being delivered through IPv4 network.
The other method for IPv4-IPv6-IPv4 scenario is tunneling. This
requires a PET to encapsulate the packets and send them to the tunnel
endpoint PET across IPv6 backbone. When these packets arrive at the
tunnel endpoint PET, they are de-capsulated and sent to IPv4 customer
networks.
Because translation method will incur information loss, PET prefers
to use tunneling technology to handle IPv4-IPv6-IPv4 scenario. Its
operations are shown in Figure 2.
+-------------+ +-------------+ +-------------+ +-------------+
|IPv4 customer| | PET | | PET | |IPv4 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|---forwarding--->| | |
| encapsulation | |
| | | |
| |-------tunneling--->| |
| | | |
| | decapsulation |
| | |------forwarding->|
| | | |
Figure 2 PET operations in IPv4-IPv6-IPv4 scenario
5.2. IPv4->IPv6->IPv6
This is the scenario where an IPv4 customer network wants to talk
with an IPv6 customer network across IPv6 backbone. There are two
methods to deal with this scenario. One is translation plus
forwarding. The other is tunneling plus translation.
In the first method, when an IPv4 packet arrives at PET, it will be
translated into an IPv6 packet and then sent to the IPv6 network
through IPv6 backbone. In the second method, when an IPv4 packet
arrives at PET, it will be encapsulated as an IPv6 packet for being
delivered through IPv6 backbone. Once this packet arrives at the
tunnel endpoint PET, it will be de-capsulated to the original IPv4
packet and then be translated as an IPv6 packet to be delivered to
the IPv6 customer network.
Cui, et al. Expires January 8, 2010 [Page 11]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
If the IPv4 customer network is not an IPv4 backbone, PET prefers to
adopt the first method because the complexity of second method is
higher than that of the first method. Its operation is shown in
Figure 3.
+-------------+ +-------------+ +-------------+ +-------------+
|IPv4 customer| | PET | | PET | |IPv6 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|-----forwarding->| | |
| translation | |
| | | |
| |------forwarding--->| |
| | | |
| | | |
| | | |
| | |-----forwarding-->|
| | | |
Figure 3 PET operations in IPv4-IPv6-IPv6 scenario (IPv4 customer
network is not a backbone)
if the IPv4 customer network is a backbone, PET prefers to adopt the
second method for the following reasons:
i) Translation mechanism usually needs application level gateway
(ALG), which is an application specific agent that allows an IPv6
node to communicate with an IPv4 node and vice versa. Backbone
network requires hardware forwarding for high speed transmission.
However, it is hard to use hardware to do the work of ALG.
ii) To avoid single point of failure, several PETs usually be
deployed among networks. They improve performance and robustness
using dynamic routing mechanism. However, translation is a static
process. It is hard to use dynamic routing mechanism.
iii) At last, some translation mechanisms, such as IVI-based scheme,
require IPv4 routing information to be introduced into IPv6 backbone,
which will increase the routing base size. Based on the above
analyses, PET refers to adopt the second method to deal with this
scenario. Its operations are shown in Figure 4.
Cui, et al. Expires January 8, 2010 [Page 12]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
+-------------+ +-------------+ +-------------+ +-------------+
|IPv4 customer| | PET | | PET | |IPv6 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|----forwarding-->| | |
| | | |
| encapsulation | |
| |------tunneling---->| |
| | | |
| | decapsulation |
| | translation |
| | |------forwarding->|
| | | |
Figure 4 PET operations in IPv4-IPv6-IPv6 scenario (IPv4 customer
network is a backbone)
5.3. IPv6->IPv6->IPv4
This is the scenario where an IPv6 customer network wants to talk
with an IPv4 customer network across IPv6 backbone. In this
scenario, when an IPv6 packet arrives at PET, it will be translated
as an IPv4 packet and then the PET encapsulates it and sends it to
the tunnel endpoint PET. When the translated IPv4 packet arrives at
the tunnel endpoint PET, it will be de-capsulated and sent to the
IPv4 customer network. The operations are shown in Figure 5.
+-------------+ +-------------+ +-------------+ +-------------+
|IPv6 customer| | PET | | PET | |IPv4 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|---forwarding--->| | |
| translation | |
| encapsulation | |
| |------tunneling---->| |
| | | |
| | | |
| | decapsulation |
| | |--forwarding----->|
| | | |
Figure 5 PET operations in IPv6-IPv6-IPv4 scenario
Cui, et al. Expires January 8, 2010 [Page 13]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
5.4. IPv6->IPv4->IPv6
This is the scenario where an IPv6 network wants to talk with another
IPv6 network across IPv4 backbone. This scenario is similar to IPv4-
IPv6-IPv4 scenario. Hence, PET prefers to use tunneling technology
to handle this scenario. Its operations are shown in Figure 6.
+-------------+ +-------------+ +-------------+ +-------------+
|IPv6 customer| | PET | | PET | |IPv6 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|---forwarding--->| | |
| encapsulation | |
| |------tunneling---->| |
| | | |
| | | |
| | decapsulation |
| | | |
| | |--forwarding----->|
| | | |
Figure 6 PET operations in IPv6-IPv4-IPv6 scenario
5.5. IPv4->IPv4->IPv6
This is the scenario where an IPv4 customer network wants to talk
with an IPv6 customer network across IPv4 backbone. This scenario is
similar to IPv6-IPv6-IPv4 scenario. Hence, PET adopts the similar
method to deal with this scenario. Its operations are shown in
Figure 7.
+-------------+ +-------------+ +-------------+ +-------------+
|IPv4 customer| | PET | | PET | |IPv6 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|---forwarding--->| | |
| translation | |
| encapsulation | |
| |------tunneling---->| |
| | | |
| | decapsulation |
| | |---forwarding---->|
| | | |
Figure 7 PET operations in IPv4-IPv4-IPv6 scenario
Cui, et al. Expires January 8, 2010 [Page 14]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
5.6. IPv6->IPv4->IPv6
This is the scenario where an IPv6 customer network wants to talk
with an IPv4 customer network across IPv4 backbone. This scenario is
similar to IPv4-IPv6-IPv6 scenario. Hence, PET adopts the similar
method to deal with this scenario. Its operations are shown in
Figures 8 and 9.
+-------------+ +-------------+ +-------------+ +-------------+
|IPv6 customer| | PET | | PET | |IPv4 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|--forwarding---->| | |
| translation | |
| | | |
| |------forwarding--->| |
| | | |
| | | |
| | | |
| | |----forwarding--->|
| | | |
Figure 8 PET operations in IPv6-IPv4-IPv4 scenario (IPv6 customer
network is not a backbone)
+-------------+ +-------------+ +-------------+ +-------------+
|IPv6 customer| | PET | | PET | |IPv4 customer|
| network | | | | | | network |
+-------------+ +-------------+ +-------------+ +-------------+
| | | |
|----forwarding-->| | |
| | | |
| encapsulation | |
| |------tunneling---->| |
| | | |
| | | |
| | decapsulation |
| | translation |
| | |---forwarding---->|
| | | |
Figure 9 PET operations in IPv6-IPv4-IPv4 scenario (IPv6 customer
network is a backbone)
Cui, et al. Expires January 8, 2010 [Page 15]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
6. Implementation issues
In this draft, we recommend how to use tunneling and translation
method in each scenario using PETs. However, we do not restrict the
specific tunneling and translation technology that PET adopts. It
can be any transition technology, such as SIIT [RFC 2765], NAT-PT
[RFC2766], BIS [RFC 2767], SOCKS64 [RFC 3089], BIA [RFC 3338],
IVI[draft-ietf-xli-behave-ivi-02], iP-in-IP tunnel [RFC 2893, RFC
4213],GRE tunnel [RFC 1702], 6to4 tunnel [RFC 2893], 6over4 tunnel
[RFC2529], softwire transition technology [RFC 5565] and so on.
In addition, this draft does not address how PET collaborates with
DNS, ALG and other transition devices, as well as inter domain
transition problems, which will discuss in the next version.
Cui, et al. Expires January 8, 2010 [Page 16]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
7. Acknowledgements
The authors would like to thank Lixia Zhang for her valuable comments
on this draft.
Cui, et al. Expires January 8, 2010 [Page 17]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
8. References
8.1. Normative References
[RFC1702] Hanks, S., Li, T., Farinacci, D., and P. Traina, "Generic
Routing Encapsulation over IPv4 networks", RFC 1702,
October 1994.
[RFC2529] Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4
Domains without Explicit Tunnels", RFC 2529, March 1999.
[RFC2765] Nordmark, E., "Stateless IP/ICMP Translation Algorithm
(SIIT)", RFC 2765, February 2000.
[RFC2766] Tsirtsis, G. and P. Srisuresh, "Network Address
Translation - Protocol Translation (NAT-PT)", RFC 2766,
February 2000.
[RFC2767] Tsuchiya, K., HIGUCHI, H., and Y. Atarashi, "Dual Stack
Hosts using the "Bump-In-the-Stack" Technique (BIS)",
RFC 2767, February 2000.
[RFC2893] Gilligan, R. and E. Nordmark, "Transition Mechanisms for
IPv6 Hosts and Routers", RFC 2893, August 2000.
[RFC3089] Kitamura, H., "A SOCKS-based IPv6/IPv4 Gateway Mechanism",
RFC 3089, April 2001.
[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.
[RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
for IPv6 Hosts and Routers", RFC 4213, October 2005.
[RFC5565] Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh
Framework", RFC 5565, June 2009.
8.2. Informative References
[I-D.xli-behave-ivi]
Li, X., Bao, C., Chen, M., Zhang, H., and J. Wu, "The
CERNET IVI Translation Design and Deployment for the IPv4/
IPv6 Coexistence and Transition", draft-xli-behave-ivi-02
(work in progress), June 2009.
Cui, et al. Expires January 8, 2010 [Page 18]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
Authors' Addresses
Yong Cui
Tsinghua University
Department of Computer Science, Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5822
Email: cy@csnet1.cs.tsinghua.edu.cn
Mingwei Xu
Tsinghua University
Department of Computer Science, Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5822
Email: xmw@csnet1.cs.tsinghua.edu.cn
Shengling Wang
Tsinghua University
Department of Computer Science, Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5822
Email: slwang@csnet1.cs.tsinghua.edu.cn
Jianping Wu
Tsinghua University
Department of Computer Science, Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5983
Email: jianping@cernet.edu.cn
Cui, et al. Expires January 8, 2010 [Page 19]
Internet-Draft PET for IPv4/IPv6 Coexistence July 2009
Xing Li
Tsinghua University
Department of Electronic Engineering, Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5983
Email: xing@cernet.edu.cn
Chris Metz
Cisco Systems, Inc.
3700 Cisco Way
San Jose, Ca. 95134
USA
Email: chmetz@cisco.com
Cui, et al. Expires January 8, 2010 [Page 20]