draft-ietf-v6ops-addr-select-req-01.txt   draft-ietf-v6ops-addr-select-req-02.txt 
IPv6 Operations Working Group A. Matsumoto IPv6 Operations Working Group A. Matsumoto
Internet-Draft T. Fujisaki Internet-Draft T. Fujisaki
Intended status: Standards Track NTT Intended status: Informational NTT
Expires: August 5, 2007 R. Hiromi Expires: November 16, 2007 R. Hiromi
K. Kanayama K. Kanayama
Intec Netcore Intec Netcore
Requirements for the address selection mechanisms May 15, 2007
draft-ietf-v6ops-addr-select-req-01.txt
Requirements for address selection mechanisms
draft-ietf-v6ops-addr-select-req-02.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 1, line 35 skipping to change at page 1, line 37
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 5, 2007. This Internet-Draft will expire on November 16, 2007.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
RFC3484 defines source and destination address selection algorithms In a multi-prefix environment, nodes could have multiple addresses on
that are commonly deployed in current popular OSs. Meanwhile, there one network interface. RFC 3484 defines source and destination
is a possibility to provide multiple addresses in one physical address-selection algorithm, which is commonly deployed in current
network. In such a multi-prefix environment, end-hosts could popular OSs. However, nodes could encounter some difficulties in
encounter some troubles in the communication because of default use network communication when they use default address selection rules
of the RFC3484 mechanism. Some mechanism for the address selection defined in RFC 3484. Some mechanisms for solving address selection
problems are proposed including RFC3484 policy table distribution and problems are proposed including the RFC 3484 policy table
RFC3484-update. This document describes the requirements for these distribution and ICMP error-based mechanisms. This document
address selection mechanisms. describes the requirements for these address selection mechanisms.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Scope of this document . . . . . . . . . . . . . . . . . . 3 2. Requirements of Address Selection . . . . . . . . . . . . . . . 3
2. Requirements of Address Selection . . . . . . . . . . . . . . 3 2.1. Effectiveness . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Contents of Policy Table . . . . . . . . . . . . . . . . . 3 2.2. Timing . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Timing . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3. Dynamic Behavior Update . . . . . . . . . . . . . . . . . . 4
2.3. Redistribution of changed Policy Table . . . . . . . . . . 4 2.4. Node-Specific Behavior . . . . . . . . . . . . . . . . . . 4
2.4. Sections . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.5. Application-Specific Behavior . . . . . . . . . . . . . . . 4
2.5. Generating Policy Table per CPE/Node . . . . . . . . . . . 4 2.6. Multiple Interface . . . . . . . . . . . . . . . . . . . . 4
2.6. Security . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.7. Central Control . . . . . . . . . . . . . . . . . . . . . . 4
3. Possible Solutions for Address Selection Problem . . . . . . . 4 2.8. Next-hop Selection . . . . . . . . . . . . . . . . . . . . 4
3.1. Routing System Assistance for Address Selection by 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
Fred Baker . . . . . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
3.2. 3484-update . . . . . . . . . . . . . . . . . . . . . . . 5 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. shim6 . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5.1. Normative References . . . . . . . . . . . . . . . . . . . 5
3.4. policy distribution mechanism . . . . . . . . . . . . . . 6 5.2. Informative References . . . . . . . . . . . . . . . . . . 5
4. Discussion at 67th IETF . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
Appendix A. Solutions for RFC3484 policy distribution . . . . . . 9
A.1. Policy distribution with router advertisement (RA)
message option . . . . . . . . . . . . . . . . . . . . . . 10
A.2. Policy distribution in DHCPv6 . . . . . . . . . . . . . . 10
A.3. Using other protocols . . . . . . . . . . . . . . . . . . 11
A.4. Defining a new protocol . . . . . . . . . . . . . . . . . 11
A.5. Converting routing information to policy table . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
7.2. Informative References . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
Intellectual Property and Copyright Statements . . . . . . . . . . 14
1. Introduction 1. Introduction
One physical network can have multiple logical networks. In that One physical network can have multiple logical networks. In that
case, an end-host has multiple IP addresses. In the IPv4-IPv6 dual case, an end-host has multiple IP addresses. ( e.g. In the IPv4-IPv6
stack environment or in a site connected to both ULA [RFC4193] and dual-stack environment, in a site that uses both ULA [RFC4193] and
global scope networks, an end-host has multiple IP addresses. These global scope addresses or in a site connected to multiple upstream
are examples of the networks that we focus on in this document. In IPv6 networks) For such a host, RFC 3484 [RFC3484] defines default
such an environment, an end-host will encounter some communication address-selection rules for the source and destination addresses.
trouble documented in PS. [I-D.arifumi-v6ops-addr-select-ps]
RFC 3484 [RFC3484] defines both source and destination address
selection algorithms. RFC 3484 defines a default address table, and
enables adding other entries to this table. Flexible address
selection can be carried out.
In addition, the distribution of an address policy table is an
important matter. RFC 3484 describes all the algorithms for setting
the address policy table, but it makes no mention of
autoconfiguration.
To make a smooth connection with the appropriate source and
destination address selection inside a multi-prefix environment,
nodes must be informed about routing policies of their upstream
networks and possible source address selection policies. Then, those
nodes must put those policies into individual policy tables.
On the other hand, the RFC3484 mechanism is commonly deployed.
However, manual configuration of the policy table is not a feasible
idea and some automatic mechanism is needed.
In this document, requirements for distribution of the address Today, the RFC 3484 mechanism is widely implemented in major OSs.
selection policy are described for promotional use of the RFC3484 However, we and others have found that in many sites the default
mechanism. address-selection rules are not appropriate for the network
structure. PS [I-D.ietf-v6ops-addr-select-ps] lists problematic
cases that resulted from incorrect address selection.
1.1. Scope of this document Though RFC 3484 made the address-selection behavior of a host
configurable, typical users cannot make use of that because of the
complexity of the mechanism and lack of knowledge about their network
topologies. Therefore, an address-selection autoconfiguration
mechanism is necessary, especially for unmanaged hosts of typical
users.
The routing information from an upstream network is necessary, but in This document contains requirements for address-selection mechanisms
this document, we are focused on how to select source and destination that enable hosts to perform appropriate address selection
addresses at the RFC3484 address policy table of the end-host. automatically.
2. Requirements of Address Selection 2. Requirements of Address Selection
2.1. Contents of Policy Table Address-selection mechanisms have to fulfill the following seven
requirements.
A Policy Table is a set of Policies described in RFC 3484. Each
Policy consists of four elements: prefix value, precedence value,
label value, and zone index value. The Policy distribution mechanism
should be able to distribute a Policy Table that has one or more
Policies to Nodes.
2.2. Timing
The Policy Table should be distributed to Nodes by a Policy broker at
any time when Nodes send a request for the Policy.
2.3. Redistribution of changed Policy Table
When a Policy broker has any change in a Policy Table that is
distributed to Nodes, the Policy broker should redistribute the
latest Policy Table to Nodes.
2.4. Sections
The Policy distribution mechanism should support being performed in
two kinds of sections: from PE to CPE and from CPE to Node. Policy
distribution mechanisms provided in each section may or many not be
the same.
2.5. Generating Policy Table per CPE/Node
The Policy distribution mechanism should allow for generating an
appropriate Policy Table per Node. For example, in some cases, each
Node may have a different set of assigned prefixes. In such a case,
the appropriate Policy Table for each Node may also be different, and
a Policy broker may be needed to generate the Policy Table according
to the identity of the Node.
2.6. Security
The Policy distribution mechanism should provide for reliable, secure
distribution of the Policy distribution from a Policy broker to
Nodes.
3. Possible Solutions for Address Selection Problem
A few mechanisms for address selection problems are proposed. This
section quickly reviews each proposal including a policy distribution
mechanism.
3.1. Routing System Assistance for Address Selection by Fred Baker
Fred Baker proposed to us about this mechanism. A host asks the DMZ
routers or the local router which is the best pair of source and
destination addresses when the host has a set of addresses A and
destination host has a set of addresses B. And then, the host uses
the policy provided by the server/routing system as a guide in
applying the response. He also proposed a mechanism that utilizes
ICMP error message to change the source address of the existing
session. This point resembles 5.2 3484-update mechanism, so the
following evaluation is based only on the first part of his proposal.
Advantages:
- A host can choose the best address pair that reflects the dynamic
changing routing status.
- The destination address selection can be handled in this
mechanisim as well as source address selection.
Disadvantages:
- A host can choose the best address pair that reflects the dynamic
- A host has to consult the routing system every time it starts a
connection if the host doesn't have address selection information
for the destination host or the information lifetime is expired.
This could be a possible scalability problem.
- A host has to wait until the response is received from the routing
system.
- The existing host/router OS implementation has to be changed a
lot. In the existing TCP/IP protocol stack implementation,
destination address selection is mainly the role of the
application and not that of the kernel unlike source address
selection. Therefore, implementing this model without causing any
affects on applications is not so easy.
3.2. 3484-update
M. Bagnulo proposed a new method of address selection in his draft.
[I-D.bagnulo-rfc3484-update] When the host notices that a network
failure occurs or packets are dropped somewhere in the network by for
example, an ingress filter, the host changes the source address of
the connection to another source address. The host stores a cache of
address selection information so that the host can select an
appropriate source address for new connections.
Advantages:
- A host can choose the best address that reflects the dynamic
changing routing status.
Disadvantages:
- A host has to learn address selection information per destination
host. The number of cache entries can be too big.
- The existing host/router OS implementation has to be changed a
lot. In particular, changing the source address of the existing
connection is not so easy and has a big impact on the existing
TCP/IP protocol stack implementation.
- There is not so much experience with this kind of address
selection cache mechanism.
- The host tries every address one-by-one, so the user has to wait
for a long time before the appropriate address pair is found.
3.3. shim6
shim6 is designed for site-multihoming. This mechanism introduces a
new method of address selection for session initiation and session
survivability, which is documented in
[I-D.ietf-shim6-locator-pair-selection] and
[I-D.ietf-shim6-failure-detection].
The shim6 host detects connection failures and changes the source
address during the session.
Advantages:
- The shim6 host performs address selection that reflects network
failures in the source and destination end-to-end link. Moreover,
network failure avoidance can be achieved by end hosts themselves.
Disadvantages:
- A host has to learn address selection information per destination
host. The number of cache entry can be too big.
- The existing host/router OS implementation has to be changed
significantly.
- The host tries every address one-by-one, so the user has to wait
for a long time before the appropriate address pair is found.
3.4. policy distribution mechanism
This mechanism takes advantages of RFC 3484 Policy Table that is
widely deployed already. By distributing policies for Policy Table,
you can auto-configure a host's address selection policy.
Advantages:
- A host can receive and understand address selection information
before the host starts a connection. Therefore, the amount of
traffic and connection overhead time can be minimized.
- A host does not need any other address-selection-related
information once that host receives the address selection policy
set. This can also reduce the amount of traffic.
- The existing OS implementation does not need to be changed
significantly on the OS that implements the RFC 3484 policy table.
Only the delivery mechanism to the table has to be prepared.
- Destination address selection can also be controlled by this
mechanism.
Disadvantages:
- No other address selection rule that is beyond the RFC 3484 policy
table framework can be implemented.
- The OS implementation has to be changed, and the policy
distribution server, such as a gateway router, has to be prepared.
- When DHCP or RA is used for transport mechanism of policy table,
frequently changing policy cannot be delivered to hosts quickly
because of the nature of these protocols.
4. Discussion at 67th IETF
Here listed some points that was raised at San Diego and comments
below. These points are classified into 3 classes from the aspect of
RFC3484. It seems to be better to settle the basis for this
discussion. That is, we can assume RFC3484 as it is now, we should
modify RFC3484 or we should start from nothing.
1) Issues that don't need RFC3484 modification">
- The ability to deliver specific set of policies to a specific host 2.1. Effectiveness
This issue is already in the requiremnt draft. The mechanism can modify RFC 3484 default address-selection behavior
at nodes. As documented in PS [I-D.ietf-v6ops-addr-select-ps], the
default rules defined in RFC 3484 do not work properly in some
environment. Therefore, the mechanism has to be able to modify
address-selection behavior of a host.
2) Issues that may need slight RFC3484 change. 2.2. Timing
- The address type dependent preference. Nodes can obtain address selection information when necessary. If
nodes need to have address-selection information before performing
address selection, then the mechanism has to provide a way for nodes
to obtain necessary information beforehand. The mechanism should not
degrade userbility. The mechanism should not enforce long address-
selection processing time upon users.
There was a thread "address selection and DHCPv6" by James Carlson 2.3. Dynamic Behavior Update
at IPv6 ML about address type dependent preference, such as
DHCPv6, RA, manual and also privacy extension(RFC3041) address.
http://www1.ietf.org/mail-archive/web/ipv6/current/msg06910.html
It is hard to define default preferences for these address types, Address-selection behavior of nodes can be dynamically updated. When
because it depends on the usage of these addresses, but not on the network structure changes and address-selection behavior has to
address types themselves. It is the policy table where you can be changed accordingly, a network administrator can modify the
control host's address selection behavior. At this time, however, address-selection behavior of nodes.
I cannot say policy table is the perfect way to fulfill this
requirement.
For example, You can set priority on 3041 address by putting a 2.4. Node-Specific Behavior
line in policy table specifying 3041 address by 128-bit prefixlen
and continuing to update policy table according to 3041 address
changes. But, this is surely troublesome for users and
implementers.
One idea is to update RFC3484 policy table definition so that it The mechanism can support node-specific address-selection behavior.
can handle alias addresses like privacy, DHCPv6 generated, RA Even when multiple nodes are on the same subnet, the mechanism should
generated, manually generated (and even Home Address ?) be able to provide a method for the network administrator to make
nodes behave differently. For example, each node may have a
different set of assigned prefixes. In such a case, the appropriate
address-selection behavior may be different.
To prefer privacy address by default, and to prefer RA-generated 2.5. Application-Specific Behavior
address for site internal, the policy table will look like this.
Prefix Pref Label The mechanism can support application-specific address-selection
2001:db8:1234::(PRIVACY)/128 30 2 behavior or combined use with an application-specific address-
::/0 10 2 selection mechanism such as address-selection APIs.
2001:db8:1234::(RA):/128 30 1
2001:db8::/48 20 1
3) Issues that need big RFC 3484 change. 2.6. Multiple Interface
- Multiple Interfaces Issues
Dave Thaler gave us comments that multiple-interface hosts may The mechanism can support those nodes equipped with multiple
face policy collision and distribution of dst address selection interfaces. The mechanism has to assume that nodes have multiple
policy and src address selection policy should be separated. interfaces and makes address selection of those nodes work
Also, per-interface policy table was proposed. appropriately.
After all, this is a policy collision problem. To make a host 2.7. Central Control
have one policy table per network interface doesn't solve policy
collision issue. Source address selection is performed after
output interface is selected, but destination address selection is
before output interface selection. In this case, destination
address selection uses all the policy tables a host has, so here
collision can happen.
Separating destination address selection and source address The address selection behavior of nodes can be centrally controlled.
selection will have a big change on RFC3484 policy table A site administrator or a service provider can determine or have
definition. Though it may be a good idea to avoid source address effect on address-selection behavior at their users' hosts.
selection policy collision.
- application specific address selection should be considered. 2.8. Next-hop Selection
Also, XML was proposed for the right format to describe those
policies.
This issue is so much application dependent. Even if policy table The mechanism can control next-hop-selection behavior at hosts or
supports application specific policies, the application doesn't cooperate with other routing mechanisms, such as routing protocols
necessarily follow the policy table. It seems to me a better idea and RFC 4191 [RFC4191]. If the address-selection mechanism is used
to use address selection APIs or application specific with a routing mechanism, the two mechanisms has to be able to work
configuration file for it. synchronousely.
5. Security Considerations 3. Security Considerations
Address false-selection can lead to serious security problem, such as Incorrect address-selection can lead to serious security problems,
session hijack. However, it should be noted that address selection such as session hijack. However, we should note that address-
is eventually up to end-hosts. We have no means to enforce one selection is ultimately decided by nodes and their users. There are
specific address selection policy to every end-host. So, a network no means to enforce a specific address-selection behavior upon every
end-host from outside of the host. Therefore, a network
administrator has to take countermeasures for unexpected address administrator has to take countermeasures for unexpected address
selection. selection.
6. IANA Considerations 4. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
Appendix A. Solutions for RFC3484 policy distribution 5. References
In this section, several mechanisms for distributing RFC3484 policy
are compared and evaluated. The reason why this section is in
appendix is that these discussions should be after address selection
mechanism selection is finished and policy distribution mechanism is
selected. solution.
As described in section 3.1, the address selection policy table
consists of four elements: prefix value, precedence, label, and zone-
index. The policy distribution mechanism will deliver lists of these
elements.
A.1. Policy distribution with router advertisement (RA) message option
The RA message can be used to deliver a policy table by adding a new
ND option. Existing ND transport mechanisms (i.e., advertisements
and solicitations) are used. Advantages and disadvantages are almost
the same as those described in [DNS configuration RFC, RA section].
In addition, an advantage and disadvantages of distributing a policy
table are as follows.
Advantages:
- The RA message is used to deliver IPv6 address prefixes.
Therefore, delivering policies for selecting addresses with the
address attached to the host would be natural.
Disadvantages:
- The RA message is limited in size, and the RA may not be
sufficient to deliver full policies. The same compression
techniques, which were adopted in RFC4191 [RFC4191] can be used to
increase the number of policies delivered by RA messages.
- Currently, RA messages are not used between a PE and CPE. Other
protocols may be necessary to deliver a policy table.
- Configuring a policy table in each router that advertises RA
messages with an address prefix is necessary, so if a site has a
lot of routers, there will be a higher management cost.
- Delivering a specific policy table to one node is impossible
because RA messages are multicast.
A.2. Policy distribution in DHCPv6
By defining a new DHCPv6 option like
[I-D.fujisaki-dhc-addr-select-opt], a policy table can be delivered.
The advantages and disadvantages are almost the same as those
described in [DNS configuration RFC, DHCPv6 section].
In addition, there are the following advantages and disadvantages.
Advantages:
- Currently, DHCPv6 prefix delegation is mainly used between a PE
and CPE. Delivering a policy table with prefixes is possible.
- A DHCPv6 server can deliver a host-specific policy table.
- By using a DHCPv6 relay mechanism, managing a policy table from a
central server is possible.
Disadvantages:
- The DHCPv6 message size is limited to the maximum UDP transmission
size, so delivering complex policies by DHCPv6 may be impossible.
A.3. Using other protocols
Using other protocols (i.e., http and ftp) to deliver the policy
table is possible.
Advantages:
- No new transport mechanisms are necessary.
Disadvantages:
- Other service discovery mechanisms will be necessary.
- The procedure to distribute information should be defined (e.g.,
when to distribute and where the information is stored).
- Existing protocols may not have a mechanism to inform clients
about policy changes.
A.4. Defining a new protocol
Defining a new protocol to deliver a policy table will have the
following advantages and disadvantages.
Advantages:
- Defining a protocol suitable for policy distribution may be
possible.
Disadvantages:
- In addition to the disadvantages of 4.3, a new transport mechanism
needs to be defined.
A.5. Converting routing information to policy table
In an environment in which routing information and network links are
separated (e.g., between PE and CPE), converting routing information
to a policy table is possible. However, when intermediate routers
and nodes receive next-hop information, that is aggregated as a
default route or neighbor router, and cannot generate policy table [a
policy table cannot be generated].
Advantages:
- No new distribution mechanism is necessary.
Disadvantages:
- This mechanism can be used only in a limited environment.
7. References
7.1. Normative References 5.1. Normative References
[I-D.arifumi-v6ops-addr-select-ps] [I-D.ietf-v6ops-addr-select-ps]
Matsumoto, A., "Problem Statement of Default Address Matsumoto, A., "Problem Statement of Default Address
Selection in Multi-prefix Environment: Operational Issues Selection in Multi-prefix Environment: Operational Issues
of RFC3484 Default Rules", of RFC3484 Default Rules",
draft-arifumi-v6ops-addr-select-ps-01 (work in progress), draft-ietf-v6ops-addr-select-ps-01 (work in progress),
October 2006. April 2007.
[RFC3484] Draves, R., "Default Address Selection for Internet [RFC3484] Draves, R., "Default Address Selection for Internet
Protocol version 6 (IPv6)", RFC 3484, February 2003. Protocol version 6 (IPv6)", RFC 3484, February 2003.
7.2. Informative References 5.2. Informative References
[I-D.bagnulo-rfc3484-update]
Bagnulo, M., "Updating RFC 3484 for multihoming support",
draft-bagnulo-rfc3484-update-00 (work in progress),
June 2006.
[I-D.fujisaki-dhc-addr-select-opt]
Fujisaki, T., "Distributing Default Address Selection
Policy using DHCPv6",
draft-fujisaki-dhc-addr-select-opt-03 (work in progress),
January 2007.
[I-D.ietf-shim6-failure-detection]
Arkko, J. and I. Beijnum, "Failure Detection and Locator
Pair Exploration Protocol for IPv6 Multihoming",
draft-ietf-shim6-failure-detection-07 (work in progress),
December 2006.
[I-D.ietf-shim6-locator-pair-selection]
Bagnulo, M., "Default Locator-pair selection algorithm for
the SHIM6 protocol",
draft-ietf-shim6-locator-pair-selection-01 (work in
progress), October 2006.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, November 2005. More-Specific Routes", RFC 4191, November 2005.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, October 2005. Addresses", RFC 4193, October 2005.
Authors' Addresses Authors' Addresses
Arifumi Matsumoto Arifumi Matsumoto
 End of changes. 34 change blocks. 
459 lines changed or deleted 110 lines changed or added

This html diff was produced by rfcdiff 1.33. The latest version is available from http://tools.ietf.org/tools/rfcdiff/