Running Multiple PLATs in 464XLAT
draft-sun-v6ops-xlat-multi-00
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| Document | Type |
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|---|---|---|---|
| Authors | Qiong Sun , Zhirong Zhang , Qin Zhao | ||
| Last updated | 2014-07-04 | ||
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draft-sun-v6ops-xlat-multi-00
Network Working Group Q. Sun
Internet-Draft Z. Zhang
Intended status: Standards Track China Telecom
Expires: January 5, 2015 Q. Zhao
BUPT
July 4, 2014
Running Multiple PLATs in 464XLAT
draft-sun-v6ops-xlat-multi-00
Abstract
The IPv6 transition has been an ongoing process throughout the world
due to the exhaustion of the IPv4 address space. The
464XLAT[RFC6877] provides a solution with limited IPv4 connectivity
across an IPv6-only network, and the android system (version 2.3 and
above) has already implemented the 464XLAT[RFC6877] and the the
Prefix discovery solution [RFC7050]. However, the current 464XLAT
architecture can only deal with the scenario with single PLAT in the
network. When operator deploys multiple PLATs with different Pref64
prefixes, 464XLAT cannot cope with multiple prefixes for different
destination addresses.
This document describes the architecture with multiple PLATs and also
the deployment considerations.
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 5, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirement of Multiple PLATs in 464XLAT . . . . . . . . . . . 3
4. Overall Architecture of multiPLATs in 464XLAT . . . . . . . . . 4
4.1. Prefix Management Server . . . . . . . . . . . . . . . . . 4
4.2. Enhanced CLAT for multiPLAT . . . . . . . . . . . . . . . . 5
5. Deployment Considerations . . . . . . . . . . . . . . . . . . . 6
5.1. Prefix Management . . . . . . . . . . . . . . . . . . . . . 6
5.2. DNS64 Consistency . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
The exhaustion of the IPv4 address space has been a practical problem
that providers are facing today. Network address migration to IPv6
is ongoing or upcoming throughout the world. The 464XLAT
architecture uses IPv4/IPv6 translation standardized in [RFC6145] and
[RFC6146]. It encourages the IPv6 transition by making IPv4 service
reachable across IPv6-only networks and providing IPv6 and IPv4
connectivity to single-stack IPv4 or IPv6 servers and peers. The
android system (version 4.3 and above) has already implemented the
464XLAT[RFC6877] and the Prefix discovery method in [RFC7050].
However, as described in section 6.3 [RFC6877], the CLAT will use the
PLAT-side translation IPv6 prefix as the destination of all
translation packets that require stageful translation to the IPv4
Internet. The Prefix Discovery method [RFC7050] cannot deal with the
scenario when different PLATs are using with different Pref64
prefixes.
This document describes the 464XLAT architecture with multiple PLATs
by combining with the existing solutions.
2. Terminology
This document use the terminologies defined in RFC6877 and RFC7050.
3. Requirement of Multiple PLATs in 464XLAT
As defined in RFC6147 [RFC6147], it allows DNS64 implementations to
be able to map specific IPv4 address ranges to separate Pref64::/n
prefixes. That allows handling of special use IPv4 addresses
[RFC6890]. Therefore, operator may deploy multiple NAT64s (PLATs in
464XLAT) for different ranges of IPv4 servers. For example, one PLAT
"A" is used when accessing IPv4-only servers in the data center, and
a different PLAT "B" is used for Internet access. These two PLATs
may have implmented different ALG types and different QoS treatment.
PLAT "A" ----- IPv4-only servers in a data center
/
IPv6-only node---<
\
PLAT "B" ----- IPv4 Internet
Figure 1: Use case of MultiPLAT
In this use case, one end user would use multiple Pref64 prefixes for
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different destinations.
Another use case to deploy multiple PLATs is for load balancing. For
example, PLAT "A" would serve approximately half of the subscribers
in one network, while PLAT "B" would serve the other half.
PLAT "A" ----- half of the subscribers
/
IPv6-only node---<
\
PLAT "B" ----- the other half of the subscribers
Figure 2: Use case of MultiPLAT
In this use case, one end user would still get one Pref64 for all
destinations, but it still needs a management system to allocate
different Pref64 prefixes for different users.
4. Overall Architecture of multiPLATs in 464XLAT
The overall architecture of multiPLATs in 464XLAT is depicted as
following. It consists of a Prefix Management Server, enhanced CLAT,
and multipe PLATs. The PLAT in this architecture has no difference
between 464XLAT in RFC[RFC6877].
+-----------------+
+----|Pref Mangt Server|
| +-----------------+
| +------+
+------+ | +-----+ / \
| CLAT |------+------+PLAT1+----| network1 |
+------+ | +-----+ \ /
| +------+
| +------+
| +-----+ / \
+------+PLAT2+----| network2 |
+-----+ \ /
+------+
Figure 1: Architecture of IPTM
4.1. Prefix Management Server
The Prefix Management Server includes the following modulars as in
Figure2.
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+---------------------------------------------+
| +---------------+ +-----------------+ |
| |Pref64 Magt | |v4addrRange Magt | |
| +---------------+ +-----------------+ |
| +---------------+ +-----------------+ |
| |IPv6Pref Magt | | Prefix Discovery| |
| +---------------+ +-----------------+ |
| +----------------------+ |
| |Policy Configuration | |
| +----------------------+ |
+---------------------------------------------+
Figure 2: Prefix Management Server Implementation Modular
It would be configured with the policy to allocate multiple Pref64s.
There are be different policies to apply. For example, it may map
specific IPv4 destination address ranges to separate Pref64 prefixes,
or map specific IPv6 source address ranges to separate Pref64
prefixes, or map both destination IPv4 address and source IPv6
address to Pref64 prefixes. The policy in Prefix Management Server
should be consistent with PLAT deployment policy.
The prefix discovery method should be able to cope with multiple
Pref64 prefixes. It may implement PCP based prefix discovery
method[RFC7225] to allcate multiple Pref64 prefixes.
4.2. Enhanced CLAT for multiPLAT
In addition to existing CLAT, the enhanced CLAT for multiPLAT should
also implement the following modulars:
+---------------------------------------------+
| +---------------+ +-----------------+ |
| |Pref64 Magt | |v4addrRange Magt | |
| +---------------+ +-----------------+ |
| +-----------------+ |
| | Prefix Discovery| |
| +-----------------+ |
+---------------------------------------------+
Figure 3: Enhanced CLAT
The prefix discovery method should be consistent with the one in the
Prefix Management Server. The Prefix Management modular will extract
the Pref64 from the prefix discovery procedure multiple Pref64
prefixes and the v4addrRange Management modular will store the
corresponding IPv4 address ranges. The prefix discovery method will
get multiple Pref64 prefixes after the authentication and IPv6
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address allcation process. Then, the CLAT will use the prefix as the
destination for specific IPv4 address ranges.
The translation and DNS modular is the same with the traditional XLAT
in [RFC6877].
5. Deployment Considerations
5.1. Prefix Management
The prefix management modular is important for multiPLATs 464XLAT.
However, since it should compare the destination address range with
each packet in CLAT, it might have effect on the performance
efficiency in the client. So, operators should limit the number of
address ranges, and aggregate the addresses into a larger address
range.
Besides, there might also be a maximum configuration limit in CLAT on
the number of Pref64 prefixes and the number of address ranges. When
the number of address ranges exceeds the limit, the CLAT may ignore
the following Pref64 prefixes and use a default prefix for the rest
of destinations. However, this may cause issues for unexpected
results.
5.2. DNS64 Consistency
464XLAT does not require DNS64 [RFC6147] when IPv4 host sends IPv4
packets to reach IPv4 servers. But 464XLAT networks may use DNS64 to
enable single stateful translation [RFC6146]. In this case, the
configuration policy in DNS64 should be consistent with Prefix
Management Server. For example, how to map different IPv4 address
ranges to Pref64 prefixes and IPv6 prefixes to Pref prefixes.
6. Security Considerations
TO BE COMPLETED
7. IANA Considerations
This document has no IANA actions.
8. Acknowledgements
The authors would like to thank the following individuals who have
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participated in the drafting, review, and discussion of this memo: TO
BE COMPLETED
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
9.2. Informative References
[RFC5571] Storer, B., Pignataro, C., Dos Santos, M., Stevant, B.,
Toutain, L., and J. Tremblay, "Softwire Hub and Spoke
Deployment Framework with Layer Two Tunneling Protocol
Version 2 (L2TPv2)", RFC 5571, June 2009.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, August 2011.
Authors' Addresses
Qiong Sun
China Telecom
No.118 Xizhimennei street, Xicheng District
Beijing 100035
P.R. China
Email: sunqiong@ctbri.com.cn
Zhirong Zhang
China Telecom
No.118 Xizhimennei street, Xicheng District
Beijing 100035
P.R. China
Email: zhangzhr@ctbri.com.cn
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Qin Zhao
BUPT
No.118 Xizhimennei street, Xicheng District
Beijing 100035
P.R. China
Email: zhaoq@bupt.edu.cn
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