Network Working Group S. Jiang
Internet Draft B. Liu
Intended status: Informational Huawei Technologies Co., Ltd
Expires: August 9, 2012 B. Carpenter
University of Auckland
February 6, 2012
IPv6 Enterprise Network Renumbering Scenarios and Guidelines
draft-ietf-6renum-enterprise-00.txt
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Abstract
This document analyzes enterprise renumbering events and describes
the best current practice among the existing renumbering mechanisms.
According to the different stages of renumbering events,
considerations and best current practices are described in three
categories: during network design, for preparation of renumbering,
and during a renumbering operation. A gap inventory is listed at the
end of this document.
Table of Contents
1. Introduction ................................................. 3
2. Enterprise Network Illustration for Renumbering .............. 3
3. Enterprise Network Renumbering Scenario Categories ........... 4
3.1. Renumbering caused by External Network Factors........... 5
3.2. Renumbering caused by Internal Network Factors........... 5
4. Network Renumbering Considerations and Best Current Practise . 5
4.1. Considerations and Best Current Practice during Network
Design ...................................................... .6
4.2. Considerations and Best Current Practice for the Preparation
of Renumbering ............................................... 9
4.3. Considerations and Best Current Practice during Renumbering
Operation ................................................... 10
5. Gap Inventory ............................................... 12
6. Security Considerations ..................................... 13
7. IANA Considerations ......................................... 13
8. Acknowledgements ............................................ 13
9. Change Log [RFC Editor please remove] ....................... 14
10. References ................................................. 14
10.1. Normative References .................................. 14
10.2. Informative References ................................ 15
Author's Addresses ............................................. 17
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1. Introduction
IPv6 site renumbering is considered difficult. Network managers
currently prefer to use Provider Independent (PI) addressing for IPv6
to attempt to minimize the need for future renumbering. However,
widespread use of PI may create very serious BGP4 scaling problems
and PI space is not always available for enterprise according to the
RIR (Regional Internet Registry) policies. It is thus desirable to
develop tools and practices that may make renumbering a simpler
process to reduce demand for IPv6 PI space. In any case, renumbering
may be necessary for other reasons.
This document undertakes scenario descriptions, including
documentation of current capabilities and existing BCPs, for
enterprise networks. It takes [RFC5887] and other relevant documents
as the primary input.
The IPv4 and IPv6 are logically separated from the perspective of
renumbering, regardless of overlapping of the IPv4/IPv6 networks or
devices. This document focuses on IPv6 only, by leaving IPv4 out of
scope. Dual-stack network or IPv4/IPv6 transition scenarios are out
of scope, too.
This document focuses on enterprise network renumbering, though most
of the analysis is also applicable to ISP network renumbering.
Renumbering in home networks is considered out of scope, though it
may also benefit from the analysis in this document.
The concept of enterprise network and a typical network illustration
are introduced first. Then, according to the different stages of
renumbering events, considerations and best current practices are
described in three categories: during network design, for preparation
of renumbering, and during renumbering operation. A gap inventory is
listed at the end of this document.
2. Enterprise Network Illustration for Renumbering
An Enterprise Network as defined in [RFC4057] is: a network that has
multiple internal links, one or more router connections to one or
more Providers, and is actively managed by a network operations
entity.
The enterprise network architecture is illustrated in the figure
below. Those entities relevant to renumbering are highlighted.
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Address reconfiguration is fulfilled either by DHCPv6 or ND
protocols. During the renumbering event, the DNS records need to be
synchronized while routing tables, ACLs and IP filtering tables in
various gateways also need to be updated, too.
Static address issue is described in a dedicated draft [I-
D.carpenter-6renum-static-problem]. (Editor's note: some major
conclusions would be included in this document if we can get
consensus on the discussion of the static address problem.)
Uplink 1 Uplink 2
| |
+---+---+ +---+---+
+---- |Gateway| --------- |Gateway| -----+
| +-------+ +-------+ |
| Enterprise Network |
| +------+ +------+ +------+ |
| | APP | |DHCPv6| | DNS | |
| |Server| |Server| +Server+ |
| +---+--+ +---+--+ +--+---+ |
| | | | |
| ---+--+---------+------+---+- |
| | | |
| +--+---+ +---+--+ |
| |Router| |Router| |
| +--+---+ +---+--+ |
| | | |
| -+---+----+-------+---+--+- |
| | | | | |
| +-+--+ +--+-+ +--+-+ +-+--+ |
| |Host| |Host| |Host| |Host| |
| +----+ +----+ +----+ +----+ |
+----------------------------------------+
Figure 1 Enterprise network illustration
It is assumed that IPv6 enterprise networks are IPv6-only, or dual-
stack in which a logical IPv6 plane is independent from IPv4. The
complicated IPv4/IPv6 co-existence scenarios are out of scope.
This document focuses on the unicast addresses; site-local, link-
local, multicast and anycast addresses are out of scope.
3. Enterprise Network Renumbering Scenario Categories
In this section, we divide enterprise network renumbering scenarios
into two categories defined by external and internal network factors,
which require renumbering for different reasons.
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3.1. Renumbering caused by External Network Factors
The most influential external network factor is the uplink ISP.
o The enterprise network switches to a new ISP. Of course, the
prefixes received from different ISPs are different. This is the
most common scenario.
Whether there is an overlap time between the old and new ISPs
would also influence the possibility whether the enterprise can
fulfill renumbering without a flag day [RFC4192].
o The renumbering event may be initiated by receiving new prefixes
from the same uplink. This might happen if the enterprise network
is switched to a different location within the network topology of
the same ISP due to various considerations, such as commercial,
performance or services reasons, etc. Alternatively, the ISP
itself might be renumbered due to topology changes or migration to
a different or additional prefix. These ISP renumbering events
would initiate enterprise network renumbering events, of course.
o The enterprise network adds new uplink(s) for multihoming
purposes. This may not a typical renumbering because the original
addresses will not be changed. However, initial numbering may be
considered as a special renumbering event. The enterprise network
removes uplink(s) or old prefixes.
3.2. Renumbering caused by Internal Network Factors
o As companies split, merge, grow, relocate or reorganize, the
enterprise network architectures may need to be re-built. This
will trigger the internal renumbering.
o The enterprise network may proactively adopt a new address scheme,
for example by switching to a new transition mechanism or stage of
a transition plan.
o The enterprise network may reorganize its topology or subnets.
4. Network Renumbering Considerations and Best Current Practices
In order to carry out renumbering in an enterprise network,
systematic planning and administrative preparation are needed.
Carefully planning and preparation could make the renumbering process
smoother.
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This section tries to give the recommended solutions or strategies
for the enterprise renumbering, chosen among existing mechanisms.
There are known gaps analyzed by [I-D.liu-6renum-gap-analysis]. If
these gaps are filled in the future, the enterprise renumbering may
be processed more automatically, with fewer issues.
4.1. Considerations and Best Current Practices during Network Design
This section describes the consideration or issues relevant to
renumbering that a network architect should carefully plan when
building or designing a new network.
- Prefix Delegation
In a large or a multi-site enterprise network, the prefix should
be carefully managed, particularly during renumbering events.
Prefix information needs to be delegated from router to router.
The DHCPv6 Prefix Delegation options [RFC3633] [I-D.ietf-dhc-pd-
exclude] provide a mechanism for automated delegation of IPv6
prefixes. DHCPv6 PD options may also be used between the
enterprise routers and their upstream ISPs.
- Usage of FQDN
In general, Fully-Qualified Domain Names (FQDNs) are recommended
to be used to configure network connectivity, such as tunnels,
whenever possible. The capability to use FQDNs as endpoint names
has been standardized in several RFCs, such as [RFC5996], although
many system/network administrators do not realize that it is there
and works well as a way to avoid manual modification during
renumbering.
Service Location Protocol [RFC2608] and multicast DNS with SRV
records for service discovery can reduce the number of places that
IP addresses need to be configured. But it should be noted that
multicast DNS is link-local only.
- Address Types
This document focuses on the dynamically-configured global unicast
addresses in enterprise networks. They are the targets of
renumbering events.
Manual-configured addresses are not scalable in medium to large
sites, hence are out of scope. Manual-configured addresses/hosts
should be avoided as much as possible.
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Unique Local Addresses (ULA, [RFC4193]) may be used for local
communications, usually inside of enterprise networks. They can be
sufficient for any host that is accessible only inside the
enterprise network and has no need for external communication
[RFC4864]. Normally, they do not need to be changed during a
global prefix renumbering event. However, they may need to be
renumbered in some rare scenarios, quite separate from the global
prefix renumbering.
- Address configuration models
In IPv6 networks, there are two auto-configuration models for
address assignment: Stateless Address Auto-Configuration (SLAAC)
by Neighbor Discovery (ND, [RFC4861, RFC4862]) and stateful
address configuration by Dynamic Host Configuration Protocol for
IPv6 (DHCPv6, [RFC3315]). In the latest work, DHCPv6 can also
support host-generated address model by assigning a prefix through
DHCPv6 messages [I-D.ietf-dhc-host-gen-id].
ND is considered easier to renumber by broadcasting a Router
Advertisement message with a new prefix. DHCPv6 can also trigger
the renumbering process by sending unicast RECONFIGURE messages,
though it may cause a large number of interactions between hosts
and DHCPv6 server.
This document has no preference between ND and DHCPv6 address
configuration models. It is network architects' job to decide
which configuration model is employed. But it should be noticed
that using DHCPv6 and ND together within one network, especially
in one subnet, may cause operational issues. For example, some
hosts use DHCPv6 as the default configuration model while some use
ND. Then the hosts' address configuration model depends on the
policies of operating systems and cannot be controlled by the
network. Section 5.1 of [I-D.liu-6renum-gap-analysis] discusses
more details on this topic. So, in general, this document
recommends using DHCPv6/SLAAC independently in different subnets.
However, since DHCPv6 is also used to configure many other network
parameters, there are ND and DHCPv6 co-existence scenarios.
Combinations of address configuration models may coexist within a
single enterprise network. [I-D.ietf-savi-mix] provides
recommendations to avoid collisions and to review collision
handling in such scenarios.
- DNS
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It is recommended that the site have an automatic and systematic
procedure for updating/synchronising its DNS records, including
both forward and reverse mapping [RFC2874]. A manual on-demand
updating model does not scale, and increases the chance of errors.
Although the A6 DNS record model [RFC2874] was designed for easier
renumbering, it has a lot of unsolved technical issues [RFC3364].
Therefore, it has been moved to experimental status [RFC3363], and
will move to historic status by [I-D.jiang-dnsext-a6-to-historic]
(It is currently in RFC Editor Queue already). So A6 is not
recommended.
In order to simplify the operation procedure, the network
architect should combine the forward and reverse DNS updates in a
single procedure.
Often, a small site depends on its ISP's DNS system rather than
maintaining its own. When renumbering, this requires
administrative coordination between the site and its ISP.
The DNS synchronization may be completed through the Secure DNS
Dynamic Update [RFC3007]. Normally, the dynamic DNS update is
achieved by DHCPv6 server on behalf of individual hosts. [RFC4704]
defined a DHCPv6 option to be used by DHCPv6 clients and servers
to exchange information about the client's FQDN and about who has
the responsibility for updating the DNS with the associated AAAA
and PTR RRs. For example, if a client wants the server to update
the FQDN-address mapping in the DNS server, it can include the
Client FQDN option with proper settings in the SOLICIT with Rapid
Commit, REQUEST, RENEW, and REBIND message originated by the
client. When DHCPv6 server gets this option, it can use the
dynamic DNS update on behalf of the client. In this document, we
promote to support this FQDN option. But since it's a DHCPv6
option, it implies that only the DHCP-managed networks are
suitable for this operation. In a model including SLAAC, host
addresses may be registered on an address registration server,
which could in fact be a DHCPv6 server; then the server would
update corresponding DNS records.
- Security
Any automatic renumbering scheme has a potential exposure to
hijacking. Malicious entity in the network can forge prefixes to
renumber the hosts. So proper network security mechanisms are
needed.
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For ND, Secure Neighbor Discovery (SEND, [RFC3971]) is a possible
solution, but it is complex and there's almost no real deployment
so far. Comparing the non-trivial deployment of SEND, RA guard
[RFC6105] is a light-weight alternative, however, it also hasn't
been widely deployed since it hasn't been published for long.
For DHCPv6, there are built-in secure mechanisms (like Secure
DHCPv6 [I-D.ietf-dhc-secure-dhcpv6]), and authentication of DHCPv6
messages [RFC3315] could be utilized. But these security
mechanisms also haven't been verified by wide real deployment.
- Miscellaneous
A site or network should also avoid embedding addresses from other
sites or networks in its own configuration data. Instead, the
Fully-Qualified Domain Names should be used. Thus, these
connections can survive after renumbering events at other sites.
This also applies to host-based connectivities.
4.2. Considerations and Best Current Practices for the Preparation of
Renumbering
In ND, it is not possible to reduce a prefix's lifetime to below two
hours. So, renumbering should not be an unplanned sudden event. This
issue could only be avoided by early planning and preparation.
This section describes several recommendations for the preparation of
enterprise renumbering event. By adopting these recommendations, a
site could be renumbered more easily. However, these recommendations
are not cost free. They might increase the daily burden of network
operation. Therefore, only those networks that are expected to be
renumbered soon or very frequently should adopt these recommendations,
with balanced consideration between daily cost and renumbering cost.
- Reduce the address preferred time or valid time or both.
Long-lifetime addresses may cause issues for renumbering events.
Particularly, some offline hosts may reconnect using these
addresses after renumbering events. Shorter preferred lifetimes
with relatively long valid lifetimes may allow short transition
periods for renumbering events and avoid frequent address
renewals.
- Reduce the DNS record TTL on the local DNS server.
The DNS AAAA resource record TTL on the local DNS server should be
manipulated to ensure that stale addresses are not cached.
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- Reduce the DNS configuration lifetime on the hosts.
Since the DNS server could be renumbered as well, the DNS
configuration lifetime on the hosts should also be reduced if
renumbering events are expected. The DNS configuration can be done
through either ND [RFC6106] or DHCPv6 [RFC3646].
- Identify long-living sessions
Any applications which maintain very long transport connections
(hours or days) should be identified in advance, if possible. Such
applications will need special handling during renumbering, so it
is important to know that they exist.
4.3. Considerations and Best Current Practices during Renumbering
Operation
Renumbering events are not instantaneous events. Normally, there is a
transition period, in which both the old prefix and the new prefix
are used in the site. Better network design and management, better
pre-preparation and longer transition period are helpful to reduce
the issues during renumbering operation.
- Within/without a flag day
As is described in [RFC4192], "a 'flag day' is a procedure in
which the network, or a part of it, is changed during a planned
outage, or suddenly, causing an outage while the network
recovers."
If renumbering event is processed within a flag day, the network
service/connectivity will be unavailable for a period until the
renumbering event is completed. It is efficient and provides
convenience for network operation and management. But network
outage is usually unacceptable for end users and enterprises. A
renumbering procedure without a flag day provides smooth address
switching, but much more operational complexity and difficulty is
introduced.
- Transition period
If renumbering transition period is longer than all address
lifetimes, after which the address leases expire, each host will
automatically pick up its new IP address. In this case, it would
be the DHCPv6 server or Router Advertisement itself that
automatically accomplishes client renumbering.
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Address deprecation should be associated with the deprecation of
associated DNS records. The DNS records should be deprecated as
early as possible, before the addresses themselves.
- Network initiative enforced renumbering
If the network has to enforce renumbering before address leases
expire, the network should initiate enforcement messages, either
in Router Advertisement messages or DHCPv6 RECONFIGURE messages.
- Impact to branch/main sites
Renumbering in main/branch site may cause impact on branch/main
site communication. The routes, ingress filtering of site's
gateways, and DNS may need to be updated. This needs careful
planning and organizing.
- DNS record update and DNS configuration on hosts
DNS records on the local DNS server should be updated if hosts are
renumbered. If the site depends on ISP's DNS system, it should
report the new host's DNS records to its ISP. During the
transition period, both old and new DNS records are valid. If the
TTLs of DNS records are shorter than the transition period, an
administrative operation may not be necessary.
DNS configuration on hosts should be updated if local recursive
DNS servers are renumbered. During the transition period, both old
and new DNS server addresses may co-exist on the hosts. If the
lifetime of DNS configuration is shorter than the transition
period, name resolving failure may be reduced to minimum. A
notification mechanism may be needed to indicate to the hosts that
a renumbering event of local recursive DNS happens or is going to
take place.
- Router awareness
In a site with multiple border routers, all border routers should
be aware of partial renumbering in order to correctly handle
inbound packets. Internal forwarding tables need to be updated.
- Border filtering
In a multihomed site, an egress router to ISP A could normally
filter packets with source addresses from other ISPs. The egress
router connecting to ISP A should be notified if the egress router
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connecting to ISP B initiates a renumbering event in order to
properly update its filter function.
- Tunnel concentrator renumbering
A tunnel concentrator itself might be renumbered. This change
should be reconfigured in relevant hosts or routers, unless the
configuration of tunnel concentrator was based on FQDN.
- Connectivity session survivability
During the renumbering operations, connectivity sessions in IP
layer would break if the old address is deprecated before the
session ends. However, the upper layer sessions may survive by
using session survivability technologies, such as SHIM6 [RFC5533].
As mentioned above, some long-living applications may need to be
handled specially.
5. Gap Inventory
This section lists a few issues that still appear to remain
unsolvable (also see [I-D.liu-6renum-gap-analysis]). Some of them may
be inherently unsolvable.
- Some environments like embedded systems might not use DHCPv6 or
SLAAC and even configuration scripts might not be an option.
This creates special problems that no general-purpose solution
is likely to address.
- TCP and UDP flows can't survive a renumbering event at either
end.
- The embedding of IPv6 unicast addresses into multicast
addresses and the embedded-RP (Rendezvous Point) [RFC3956] will
cause issues when renumbering.
- Changing the unicast source address of a multicast sender might
also be an issue for receivers.
- When a renumbering event takes place, entries in the state
table of tunnel concentrator that happen to contain the old
addresses will become invalid and will eventually time out.
However, this can be considered as harmless though it takes
resources on these devices for a while.
- A site that is listed in an IP black list can escape that list
by renumbering itself. The site itself of course will not
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report its renumbering and the black list may not be able to
monitor or discover the renumbering event.
- Multihomed sites, using SLAAC for one address prefix and DHCPv6
for another, would clearly create a risk of inconsistent host
behaviour and operational confusion.
6. Security Considerations
As noted, a site that is listed by IP address in a black list can
escape that list by renumbering itself.
Any automatic renumbering scheme has a potential exposure to
hijacking. Proper network security mechanisms are needed. Although
there are existing security mechanisms such as SEND, RA guard, secure
DHCPv6 etc., they haven't been widely deployed and haven't been
verified whether they are suitable for ensuring security while not
bringing too much operational complexity and cost.
Dynamic DNS update may bring risk of DoS attack to the DNS server. So
along with the update authentication, session filtering/limitation
may also be needed.
The "make-before-break" approach of [RFC4192] requires the routers
keep advertising the old prefixes for some time. But if the ISP
changes the prefixes very frequently, the co-existence of old and new
prefixes may cause potential risk to the enterprise routing system.
However, enterprise scenarios may not involve the extreme situation;
this issue needs to be identified in the future.
The security configuration updates will need to be made in two stages
(immediately before and immediately after the event).
7. IANA Considerations
This draft does not request any IANA action.
8. Acknowledgements
This work is illuminated by RFC 5887, so thank for RFC 5887 authors,
Randall Atkinson and Hannu Flinck. Useful ideas were also presented
in by documents from Tim Chown and Fred Baker. The authors also want
to thank Wesley George, Olivier Bonaventure and other 6renum members
for valuable comments.
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9. Change Log [RFC Editor please remove]
draft-jiang-6renum-enterprise-00, original version, 2011-07-01
draft-jiang-6renum-enterprise-01, Update according to IETF81 and mail
list discussions, 2011-10-09
draft-jiang-6renum-enterprise-02, Update according to IETF82
discussions, 2011-12-06
draft-ietf-6renum-enterprise-00, Update according to mail list
discussions, 2012-02-06
10. References
10.1. Normative References
[RFC2608] Guttman, E., Perkins, C., Veizades, J., and M. Day "Service
Location Protocol, Version 2", RFC 2608, June 1999.
[RFC3007] B. Wellington, "Secure Domain Name System (DNS) Dynamic
Update", RFC 3007, November 2000.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and
M. Carney, "Dynamic Host Configuration Protocol for IPv6
(DHCPv6)", RFC 3315, July 2003.
[RFC3633] Troan, O., and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC3646] R. Droms, "DNS Configuration options for Dynamic Host
Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
December 2003.
[RFC3956] Savola, P., and B. Haberman, "Embedding the Rendezvous
Point (RP) Address in an IPv6 Multicast Address", RFC 3956,
November 2004
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander
"SEcure Neighbor Discovery (SEND)", RFC 3971, March 2005
[RFC4193] Hinden, R., and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, October 2005.
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[RFC4704] B. Volz, "The Dynamic Host Configuration Protocol for IPv6
(DHCPv6) Client Fully Qualified Domain Name (FQDN) Option",
RFC 4706, October 2006.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007.
[RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, "Internet
Key Exchange Protocol Version 2 (IKEv2)", RFC 5996,
September 2010.
[RFC6106] Jeong, J., Ed., Park, S., Beloeil, L., and S. Madanapalli
"IPv6 Router Advertisement Option for DNS Configuration",
RFC 6106, November 2011.
10.2. Informative References
[RFC2874] Crawford, M., and C. Huitema, "DNS Extensions to Support
IPv6 Address Aggregation and Renumbering", RFC 2874, July
2000.
[RFC3363] R. Bush, A. Durand, B. Fink, O. Gudmundsson, T. Hain,
"Representing Internet Protocol version 6 (IPv6) Addresses
in the Domain Name System (DNS)", RFC 3363, August 2002.
[RFC3364] R. Austein, "Tradeoffs in Domain Name System (DNS) Support
for Internet Protocol version 6 (IPv6)", RFC 3364, August
2002.
[RFC4057] J. Bound, Ed. "IPv6 Enterprise Network Scenarios", RFC
4057, June 2005.
[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
Renumbering an IPv6 Network without a Flag Day", RFC 4192,
September 2005.
[RFC4864] Van de Velde, G., T. Hain, R. Droms, B. Carpenter, E. Klein,
Local Network Protection for IPv6", RFC 4864, May 2007.
[RFC5533] Nordmark, E., and Bagnulo, M., "Shim6: Level 3 Multihoming
Shim Protocol for IPv6", RFC 5533, June 2009.
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[RFC5887] Carpenter, B., Atkinson, R., and H. Flinck, "Renumbering
Still Needs Work", RFC 5887, May 2010.
[RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J.
Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105,
February 2011.
[I-D.ietf-dhc-secure-dhcpv6]
Jiang, S., and S. Shen, "Secure DHCPv6 Using CGAs", working
in progress.
[I-D.ietf-dhc-host-gen-id]
S. Jiang, F. Xia, and B. Sarikaya, "Prefix Assignment in
DHCPv6", draft-ietf-dhc-host-gen-id (work in progress),
April, 2011.
[I-D.ietf-savi-mix]
Bi, J., Yao, G., Halpern, J., and Levy-Abegnoli, E., "SAVI
for Mixed Address Assignment Methods Scenario", working in
progress.
[I-D.ietf-dhc-pd-exclude]
J. Korhonen, T. Savolainen, S. Krishnan, O. Troan, "Prefix
Exclude Option for DHCPv6-based Prefix Delegation", working
in progress.
[I-D.ietf-6renum-gap-analysis]
Liu, B., and Jiang, S., "IPv6 Site Renumbering Gap
Analysis", working in progress.
[I-D.jiang-dnsext-a6-to-historic]
Jiang, S., Conrad, D. and Carpenter, B., "Moving A6 to
Historic Status", working in progress.
[I-D.carpenter-6renum-static-problem]
Carpenter, B. and S. Jiang., "Problem Statement for
Renumbering IPv6 Hosts with Static Addresses", working in
progress.
Jiang, et al. Expires August 10, 2012 [Page 16]
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Author's Addresses
Sheng Jiang
Huawei Technologies Co., Ltd
Huawei Q14 Building, No.156 Beiqing Rd.,
Zhong-Guan-Cun Environmental Protection Park, Hai-Dian District
EMail: jiangsheng@huawei.com
Bing Liu
Huawei Technologies Co., Ltd
Huawei Q14 Building, No.156 Beiqing Rd.,
Zhong-Guan-Cun Environmental Protection Park, Hai-Dian District
EMail: leo.liubing@huawei.com
Brian Carpenter
Department of Computer Science
University of Auckland
PB 92019
Auckland, 1142
New Zealand
EMail: brian.e.carpenter@gmail.com
