Internet DRAFT - draft-ietf-6renum-enterprise
draft-ietf-6renum-enterprise
Network Working Group S. Jiang
Internet Draft B. Liu
Intended status: Informational Huawei Technologies Co., Ltd
Expires: July 18, 2013 B. Carpenter
University of Auckland
January 15, 2013
IPv6 Enterprise Network Renumbering Scenarios,
Considerations and Methods
draft-ietf-6renum-enterprise-06.txt
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Abstract
This document analyzes events that cause renumbering and describes
the current renumbering methods. These are described in three
categories: those applicable during network design, those applicable
during preparation for renumbering, and those applicable during the
renumbering operation.
Table of Contents
1. Introduction ................................................. 3
2. Enterprise Network Illustration for Renumbering .............. 3
3. Enterprise Network Renumbering Scenario Categories ........... 5
3.1. Renumbering Caused by External Network Factors .......... 5
3.2. Renumbering caused by Internal Network Factors .......... 6
4. Network Renumbering Considerations and Current Methods ....... 6
4.1. Considerations and Current Methods during Network Design. 6
4.2. Considerations and Current Methods for the Preparation of
Renumbering ................................................. 10
4.3. Considerations and Current Methods during Renumbering
Operation ................................................... 12
5. Security Considerations ..................................... 14
6. IANA Considerations ......................................... 14
7. Acknowledgements ............................................ 14
8. References .................................................. 15
8.1. Normative References .................................. 15
8.2. Informative References ................................. 16
Author's Addresses ............................................. 18
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1. Introduction
Site renumbering is difficult. Network managers frequently attempt
to avoid future renumbering by numbering their network resources
from Provider Independent (PI) address space. However, widespread
use of PI would aggravate BGP4 scaling problems [RFC4116] and,
depending on Regional Internet Registry (RIR) policies, PI space is
not always available for enterprises of all sizes. Therefore, it is
desirable to develop mechanisms that simplify IPv6 renumbering for
enterprises.
This document is an analysis of IPv6 site renumbering for enterprise
networks. It undertakes scenario descriptions, including
documentation of current capabilities and existing practices. The
reader is assumed to be familiar with [RFC4192] and [RFC5887].
Proposals for new technology and methods are out of scope.
Since IPv4 and IPv6 are logically separate from the perspective of
renumbering, regardless of overlapping of the IPv4/IPv6 networks or
devices, this document focuses on IPv6 only, 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; however,
most of the analysis is also applicable to ISP network renumbering.
Renumbering in home networks is out of scope, but it can also
benefit from the analysis in this document.
The concept of an enterprise network and a typical network
illustration are introduced first. Then, current renumbering methods
are introduced according to the following categories: those
applicable during network design, those applicable during
preparation for renumbering, and those applicable during the
renumbering operation.
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.
Figure 1 provides a sample enterprise network architecture for a
simple case. Those entities mainly affected by renumbering are
illustrated:
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* Gateway: Border router, firewall, web cache, etc.
* Application server (for internal or external users)
* DNS and DHCP servers
* Routers
* Hosts (desktops etc.)
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
Address reconfiguration is fulfilled either by the Dynamic Host
configuration Protocol for IPv6 (DHCPv6) or Neighbor Discovery for
IPv6 (ND) protocols. During a renumbering event, the Domain Name
Service (DNS) records need to be synchronized while routing tables,
Access Control Lists (ACLs) and IP filtering tables in various
devices also need to be updated. It is taken for granted that
applications will work entirely on the basis of DNS names, but any
direct dependencies on IP addresses in application layer entities
must also be updated.
The issue of static addresses is described in a dedicated draft
[I-D.ietf-6renum-static-problem].
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The emerging cloud-based enterprise network architecture might be
different with Figure 1. But it is out of the scope of this document
since the it is far from mature and has not been widely deployed yet.
It is assumed that IPv6 enterprise networks are IPv6-only, or dual-
stack in which a logical IPv6 plane is independent from IPv4. As
mentioned above, IPv4/IPv6 co-existence scenarios are out of scope.
This document focuses on routable unicast addresses; link-local,
multicast and anycast addresses are also 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.
3.1. Renumbering Caused by External Network Factors
The following ISP uplink-related events can cause renumbering:
o The enterprise network switches to a new ISP. When this occurs,
the enterprise stop numbering its resources from the prefix
allocated by the old ISP and renumbers its resources from the
prefix allocated by the new ISP.
When the enterprise switches ISPs, a "flag day" renumbering event
[RFC4192] may be averted if, during a transitional period, the
enterprise network may number its resources from either prefix.
One way to facilitate such a transitional period is for the
enterprise to contract for service from both ISPs during the
transition.
o The renumbering event can 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 might not be a typical renumbering case 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.
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3.2. Renumbering caused by Internal Network Factors
o As companies split, merge, grow, relocate or reorganize, the
enterprise network architectures might need to be re-built. This
will trigger partial or total internal renumbering.
o The enterprise network might 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 might reorganize its topology or subnets.
4. Network Renumbering Considerations and Current Methods
In order to carry out renumbering in an enterprise network,
systematic planning and administrative preparation are needed.
Careful planning and preparation could make the renumbering process
smoother.
This section describes current solutions or strategies for
enterprise renumbering, chosen among existing mechanisms. There are
known gaps analyzed by [I-D.ietf-6renum-gap-analysis] and
[I-D.ietf-6renum-static-problem]. If these gaps are filled in the
future, enterprise renumbering can be processed more automatically,
with fewer issues.
4.1. Considerations and Current Methods 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] and [RFC6603]
provide a mechanism for automated delegation of IPv6 prefixes.
Normally, DHCPv6 Prefix Delegation (PD) options are used between
the internal enterprise routers, for example, a router receives
prefix(es) from its upstream router (a border gateway or edge
router etc.) through DHCPv6 PD options and then advertises it
(them) to the local hosts through Router Advertisement (RA)
messages.
- Usage of FQDN
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In general, Fully-Qualified Domain Names (FQDNs) are recommended
to be used to configure network connectivity, such as tunnels,
servers etc. The capability to use FQDNs as endpoint names has
been standardized in several RFCs, for example for IPsec
[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.
Note that using FQDN would rely on DNS systems. For a link local
network that does not have a DNS system, multicast DNS
[I-D.cheshire-dnsext-multicastdns] could be utilized. For some
specific circumstances, using FQDN might not be chosen if adding
DNS service in the node/network would cause undesired complexity
or issues.
Service discovery protocols such as Service Location Protocol
[RFC2608], multicast DNS with SRV records and DNS Service
Discovery [I-D.cheshire-dnsext-dns-sd] use names and can reduce
the number of places that IP addresses need to be configured. But
it should be noted that these protocols are normally used link-
local only.
Network designers generally have little control over the design of
application software. However, it is important to avoid any
software that has built-in dependency on IP addresses instead of
FQDNs [I-D.ietf-6renum-static-problem].
- Usage of Parameterized Address Configuration
Besides DNS records, IP addresses might also be configured in many
other places such as ACLs, various IP filters, various kinds of
text-based configuration files, etc.
In some cases, one IP address can be defined as a value once, and
then the administrators can use either keywords or variables to
call the value in other places such as a sort of internal
inheritance in CLI (command line interface) or other local
configurations. Among the real current devices, some routers
support defining multiple loopback interfaces which can be called
in other configurations. For example, when defining a tunnel, it
can call the defined loopback interface to use its address as the
local address of the tunnel.
This kind of parameterized address configuration is recommended,
since it makes managing a renumbering event easier by reducing the
number of places where a device's configuration must be updated.
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- Usage of ULA
Unique Local Addresses (ULAs) are defined in [RFC4193] as
provider-independent prefixes. Since there is a 40 bits pseudo
random field in the ULA prefix, there is no practical risk of
collision (please refer to section 3.2.3 in [RFC4193] for more
detail). For enterprise networks, using ULA simultaneously with
Provider Aggregated (PA) addresses can provide a logically local
routing plane separated from the global routing plane. The benefit
is to ensure stable and specific local communication regardless of
any ISP uplink failure. This benefit is especially meaningful for
renumbering. It mainly includes three use cases described below.
During the transition period, it is desirable to isolate local
communication changes in the global routing plane. If we use
ULA for the local communication, this isolation is achieved.
Enterprise administrators might want to avoid the need to
renumber their internal-only, private nodes when they have to
renumber the PA addresses of the whole network because of
changing ISPs, ISPs restructuring their address allocation, or
any other reasons. In these situations, ULA is an effective
tool for the internal-only nodes.
ULA can be a way of avoiding renumbering from having an impact
on multicast. In most deployments multicast is only used
internally (intra-domain), and the addresses used for
multicast sources and Rendezvous-Points need not be reachable
nor routable externally. Hence one may at least internally
make use of ULA for multicast specific infrastructure.
- Address Types
This document focuses on the dynamically-configured global unicast
addresses in enterprise networks. They are the targets of
renumbering events.
Manually-configured addresses are not scalable in medium to large
sites, hence should be avoided for both network elements and
application servers [I-D.ietf-6renum-static-problem].
- Address configuration models
In IPv6 networks, there are two auto-configuration models for
address assignment after each host obtains a link-local address:
Stateless Address Auto-Configuration (SLAAC, [RFC4862]) by
Neighbor Discovery (ND, [RFC4861]) and stateful address
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configuration by Dynamic Host Configuration Protocol for IPv6
(DHCPv6, [RFC3315]). In the latest work, DHCPv6 may also support
the host-generated address model by assigning a prefix through
DHCPv6 messages [I-D.ietf-dhc-host-gen-id].
SLAAC is considered to support easy renumbering by broadcasting a
Router Advertisement message with a new prefix. DHCPv6 can also
trigger the renumbering process by sending unicast RECONFIGURE
messages, though it might cause a large number of interactions
between hosts and the DHCPv6 server.
This document has no preference between the SLAAC and DHCPv6
address configuration models. It is the network architects' job to
decide which configuration model is employed. But it should be
noticed that using DHCPv6 and SLAAC together within one network,
especially in one subnet, might 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.ietf-6renum-gap-analysis] discusses more details on this
topic. So, in general, this document recommends using DHCPv6 or
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 might 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
Although the A6 DNS record model [RFC2874] was designed for easier
renumbering, it left many unsolved technical issues [RFC3364].
Therefore, it has been moved to historic status [RFC6563] and
should not be used.
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.
It is recommended that the site have an automatic and systematic
procedure for updating/synchronizing its DNS records, including
both forward and reverse mapping. In order to simplify the
operational procedure, the network architect should combine the
forward and reverse DNS updates in a single procedure. A manual
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on-demand updating model does not scale, and increases the chance
of errors. Either a database-driven mechanism, or Secure Dynamic
DNS Update [RFC3007], or both, could be used.
Dynamic DNS update can be provided by the DHCPv6 client or by the
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 (Pointer Record) RRs (Resource Records). 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 Secure Dynamic DNS update on behalf of the
client. This document suggests use of this FQDN option. However,
since it is a DHCPv6 option, only the DHCP-managed hosts can make
use of it. In SLAAC mode, hosts need either to use Secure Dynamic
DNS Update directly, or to register addresses on a registration
server. This could in fact be a DHCPv6 server (as described in
[I-D.ietf-dhc-addr-registration]); then the server would update
corresponding DNS records.
- Security
Any automatic renumbering scheme has a potential exposure to
hijacking. A malicious entity in the network could forge prefixes
to renumber the hosts, so proper network security mechanisms are
needed. Further details are in the Security Considerations below.
- 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, connections can
be restored after renumbering events at other sites. This also
applies to host-based connectivity.
4.2. Considerations and Current Methods 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,
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a site could be renumbered more easily. However, these
recommendations might increase the daily traffic, server load, or
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 might cause issues for renumbering events.
Particularly, some offline hosts might 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.
Recent research [BA2011] [JSBM2002] indicates that it is both
practical and reasonable for A, AAAA, and PTR records that belong
to leaf nodes of the DNS (i.e. not including the DNS root or DNS
top-level domains) to be configured with very short DNS TTL
values, not only during renumbering events, but also for longer-
term operation.
- 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. In ND, the DNS configuration can
be done through reducing the lifetime value in RDNSS option
[RFC6106]. In DHCPv6, the DNS configuration option specified in
[RFC3646] doesn't provide a lifetime attribute, but we can reduce
the DHCPv6 client lease time to achieve similar effect.
- 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.
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4.3. Considerations and Current Methods 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.
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 DHCPv6 RECONFIGURE messages.
For some operating systems such as Windows 7, if the hosts receive
RA messages with ManagedFlag=0, they'll release the DHCPv6
addresses and do SLAAC according to the prefix information in the
RA messages, so this could be another enforcement method for some
specific scenarios.
- Impact to branch/main sites
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Renumbering in main/branch site might cause impact on branch/main
site communication. The routes, ingress filtering of site's
gateways, and DNS might 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 might 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 might 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.
- 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.
For IPSec, IKEv2 [RFC5996] defines the ID_FQDN Identification
Type, which could be used to identify an IPsec VPN concentrator
associated with a site's domain name. For current practice, the
community needs to change its bad habit of using IPsec in an
address-oriented way, and renumbering is one of the main reasons
for that.
- 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 can survive by
using session survivability technologies, such as SHIM6 [RFC5533].
As mentioned above, some long-living applications may need to be
handled specially.
- Verification of success
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The renumbering operation should end with a thorough check that
all network elements and hosts are using only the new prefixes and
that network management and monitoring systems themselves are
still operating correctly. A database clean-up may also be needed.
5. Security Considerations
Any automatic renumbering scheme has a potential exposure to
hijacking by an insider attack. For attacks on ND, Secure Neighbor
Discovery (SEND) [RFC3971] is a possible solution, but it is complex
and there is almost no real deployment at the time of writing.
Compared to the non-trivial deployment of SEND, RA Guard [RFC6105]
is a lightweight alternative, which focuses on preventing rogue
router advertisements in a network. However, it was also not widely
deployed at the time when this memo was published.
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 have
not been verified by widespread deployment at the time of writing.
A site that is listed by IP address in a black list can escape that
list by renumbering itself. However, the new prefix might be back on
a black list rather soon, if the root cause for being added to such
a list is not corrected. In practice, the cost of renumbering will
be typically much larger than the cost of getting off the black list.
Dynamic DNS update might bring risk of DoS attack to the DNS server.
So along with the update authentication, session
filtering/limitation might 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 might cause potential risk to the enterprise routing
system, since the old address relevant route path might already
invalid and the routing system just doesn't know it. However,
normally enterprise scenarios don't involve the extreme situation.
6. IANA Considerations
This draft does not request any IANA action.
7. Acknowledgements
This work is inspired by RFC5887, so thank for RFC 5887 authors,
Randall Atkinson and Hannu Flinck. Useful ideas were also presented
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in by documents from Tim Chown and Fred Baker. The authors also want
to thank Wesley George, Olivier Bonaventure, Lee Howard, Ronald
Bonica, other 6renum members, and several reviewers for valuable
comments.
8. References
8.1. 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.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander
"SEcure Neighbor Discovery (SEND)", RFC 3971, March 2005
[RFC4057] J. Bound, Ed. "IPv6 Enterprise Network Scenarios",
RFC 4057, June 2005.
[RFC4193] Hinden, R., and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, October 2005.
[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.
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[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.
8.2. Informative References
[RFC2874] Crawford, M., and C. Huitema, "DNS Extensions to Support
IPv6 Address Aggregation and Renumbering", RFC 2874, July
2000.
[RFC3364] R. Austein, "Tradeoffs in Domain Name System (DNS) Support
for Internet Protocol version 6 (IPv6)", RFC 3364, August
2002.
[RFC4116] J. Abley, K. Lindqvist, E. Davies, B. Black, and V. Gill,
"IPv4 Multihoming Practices and Limitations", RFC 4116,
July 2005.
[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
Renumbering an IPv6 Network without a Flag Day", RFC 4192,
September 2005.
[RFC5533] Nordmark, E., and Bagnulo, M., "Shim6: Level 3 Multihoming
Shim Protocol for IPv6", RFC 5533, June 2009.
[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.
[RFC6563] Jiang, S., Conrad, D. and Carpenter, B., "Moving A6 to
Historic Status", RFC 6563, May 2012.
[RFC6603] J. Korhonen, T. Savolainen, S. Krishnan, O. Troan, "Prefix
Exclude Option for DHCPv6-based Prefix Delegation", RFC
6603, May 2012.
[I-D.ietf-dhc-secure-dhcpv6]
Jiang, S., and S. Shen, "Secure DHCPv6 Using CGAs",
working in progress, March 2012.
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[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),
August, 2012.
[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, April 2012.
[I-D.ietf-dhc-addr-registration]
Jiang, S., Chen, G., "A Generic IPv6 Addresses
Registration Solution Using DHCPv6", working in progress,
May 2012.
[I-D.ietf-6renum-gap-analysis]
Liu, B., and Jiang, S., "IPv6 Site Renumbering Gap
Analysis", working in progress, August 2012.
[I-D.ietf-6renum-static-problem]
Carpenter, B. and S. Jiang., "Problem Statement for
Renumbering IPv6 Hosts with Static Addresses", working in
progress, August 2012.
[I-D.cheshire-dnsext-dns-sd]
Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", draft-cheshire-dnsext-dns-sd-11 (work in
progress), December 2011.
[I-D.cheshire-dnsext-multicastdns]
Cheshire, S. and M. Krochmal, "Multicast DNS", draft-
cheshire-dnsext-multicastdns-15 (work in progress),
December 2011.
[BA2011] Bhatti, S. and R. Atkinson, "Reducing DNS Caching", Proc.
14th IEEE Global Internet Symposium (GI2011), Shanghai,
China. 15 April 2011.
[JSBM2002] J. Jung, E. Sit, H. Balakrishnan, & R. Morris, "DNS
Performance and the Effectiveness of Caching", IEEE/ACM
Transactions on Networking, 10(5):589-603, 2002.
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Author's Addresses
Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus
No.156 Beiqing Rd.
Hai-Dian District, Beijing 100095
P.R. China
EMail: jiangsheng@huawei.com
Bing Liu
Huawei Technologies Co., Ltd
Q14, Huawei Campus
No.156 Beiqing Rd.
Hai-Dian District, Beijing 100095
P.R. China
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
Jiang, et al. July 18, 2013 [Page 18]
