< draft-ietf-ipv6-unique-local-addr-08.txt   draft-ietf-ipv6-unique-local-addr-09.txt >
INTERNET-DRAFT R. Hinden, Nokia INTERNET-DRAFT R. Hinden, Nokia
November 16, 2004 B. Haberman, JHU-APL January 21, 2005 B. Haberman, JHU-APL
Unique Local IPv6 Unicast Addresses Unique Local IPv6 Unicast Addresses
<draft-ietf-ipv6-unique-local-addr-08.txt> <draft-ietf-ipv6-unique-local-addr-09.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is subject to all provisions This document is an Internet-Draft and is subject to all provisions
of section 3 of RFC 3667. By submitting this Internet-Draft, each of section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of author represents that any 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 is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with which he or she become aware will be disclosed, in accordance with
RFC 3668. RFC 3668.
skipping to change at page 1, line 34 skipping to change at page 1, line 35
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 expires on May 21, 2005. This internet draft expires on July 26, 2005.
Abstract Abstract
This document defines an IPv6 unicast address format that is globally This document defines an IPv6 unicast address format that is globally
unique and is intended for local communications, usually inside of a unique and is intended for local communications, usually inside of a
site. They are not expected to be routable on the global Internet. site. They are not expected to be routable on the global Internet.
Table of Contents Table of Contents
1.0 Introduction....................................................2 1.0 Introduction....................................................2
2.0 Acknowledgments.................................................3 2.0 Acknowledgments.................................................3
3.0 Local IPv6 Unicast Addresses....................................3 3.0 Local IPv6 Unicast Addresses....................................3
3.1 Format..........................................................3 3.1 Format..........................................................3
3.1.1 Background....................................................4 3.1.1 Background....................................................4
3.2 Global ID.......................................................5 3.2 Global ID.......................................................5
3.2.1 Locally Assigned Global IDs...................................5 3.2.1 Locally Assigned Global IDs...................................5
3.2.2 Sample Code for Pseudo-Random Global ID Algorithm.............6 3.2.2 Sample Code for Pseudo-Random Global ID Algorithm.............5
3.2.3 Analysis of the Uniqueness of Global IDs......................6 3.2.3 Analysis of the Uniqueness of Global IDs......................6
3.3 Scope Definition................................................7 3.3 Scope Definition................................................7
4.0 Operational Guidelines..........................................7 4.0 Operational Guidelines..........................................7
4.1 Routing.........................................................7 4.1 Routing.........................................................7
4.2 Renumbering and Site Merging....................................8 4.2 Renumbering and Site Merging....................................8
4.3 Site Border Router and Firewall Packet Filtering................8 4.3 Site Border Router and Firewall Packet Filtering................8
4.4 DNS Issues......................................................9 4.4 DNS Issues......................................................9
4.5 Application and Higher Level Protocol Issues....................9 4.5 Application and Higher Level Protocol Issues....................9
4.6 Use of Local IPv6 Addresses for Local Communications...........10 4.6 Use of Local IPv6 Addresses for Local Communications...........10
4.7 Use of Local IPv6 Addresses with VPNs..........................11 4.7 Use of Local IPv6 Addresses with VPNs..........................11
5.0 Advantages and Disadvantages...................................11 5.0 Global Routing Considerations..................................11
6.0 Security Considerations........................................12 5.1 From the Standpoint of the Internet............................11
7.0 IANA Considerations............................................12 5.2 From the Standpoint of a Site..................................12
8.0 References.....................................................12 6.0 Advantages and Disadvantages...................................12
8.1 Normative References...........................................12 7.0 Security Considerations........................................13
8.2 Informative References.........................................13 8.0 IANA Considerations............................................13
9.0 Authors' Addresses.............................................13 9.0 References.....................................................13
10.0 Change Log....................................................15 9.1 Normative References...........................................13
11.0 Disclaimer of Validity........................................17 9.2 Informative References.........................................14
12.0 Copyright Statement...........................................17 10.0 Authors' Addresses............................................15
11.0 Change Log....................................................16
12.0 Intellectual Property.........................................18
13.0 Disclaimer of Validity........................................19
14.0 Copyright Statement...........................................19
1.0 Introduction 1.0 Introduction
This document defines an IPv6 unicast address format that is globally This document defines an IPv6 unicast address format that is globally
unique and is intended for local communications [IPV6]. These unique and is intended for local communications [IPV6]. These
addresses are called Unique Local IPv6 Unicast Addresses and are addresses are called Unique Local IPv6 Unicast Addresses and are
abbreviated in this document as Local IPv6 addresses. They are not abbreviated in this document as Local IPv6 addresses. They are not
expected to be routable on the global Internet. They are routable expected to be routable on the global Internet. They are routable
inside of a more limited area such as a site. They may also be inside of a more limited area such as a site. They may also be
routed between a limited set of sites. routed between a limited set of sites.
Local IPv6 unicast addresses have the following characteristics: Local IPv6 unicast addresses have the following characteristics:
- Globally unique prefix. - Globally unique prefix (with high probability of uniqueness).
- Well known prefix to allow for easy filtering at site - Well known prefix to allow for easy filtering at site
boundaries. boundaries.
- Allows sites to be combined or privately interconnected without - Allows sites to be combined or privately interconnected without
creating any address conflicts or requiring renumbering of creating any address conflicts or requiring renumbering of
interfaces using these prefixes. interfaces using these prefixes.
- Internet Service Provider independent and can be used for - Internet Service Provider independent and can be used for
communications inside of a site without having any permanent or communications inside of a site without having any permanent or
intermittent Internet connectivity. intermittent Internet connectivity.
- If accidentally leaked outside of a site via routing or DNS, - If accidentally leaked outside of a site via routing or DNS,
there is no conflict with any other addresses. there is no conflict with any other addresses.
skipping to change at page 3, line 26 skipping to change at page 3, line 33
border routers, DNS, application support, VPN usage, and guidelines border routers, DNS, application support, VPN usage, and guidelines
for how to use for local communication inside a site. for how to use for local communication inside a site.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC 2119]. document are to be interpreted as described in [RFC 2119].
2.0 Acknowledgments 2.0 Acknowledgments
The underlying idea of creating Local IPv6 addresses described in The underlying idea of creating Local IPv6 addresses described in
this document been proposed a number of times by a variety of people. this document has been proposed a number of times by a variety of
The authors of this draft do not claim exclusive credit. Credit goes people. The authors of this draft do not claim exclusive credit.
to Brian Carpenter, Christian Huitema, Aidan Williams, Andrew White, Credit goes to Brian Carpenter, Christian Huitema, Aidan Williams,
Charlie Perkins, and many others. The authors would also like to Andrew White, Charlie Perkins, and many others. The authors would
thank Brian Carpenter, Charlie Perkins, Harald Alvestrand, Keith also like to thank Brian Carpenter, Charlie Perkins, Harald
Moore, Margaret Wasserman, Shannon Behrens, Alan Beard, Hans Kruse, Alvestrand, Keith Moore, Margaret Wasserman, Shannon Behrens, Alan
Geoff Huston, Pekka Savola, Christian Huitema, Tim Chown, Steve Beard, Hans Kruse, Geoff Huston, Pekka Savola, Christian Huitema, Tim
Bellovin, Alex Zinin, Tony Hain, and Bill Fenner for their comments Chown, Steve Bellovin, Alex Zinin, Tony Hain, Bill Fenner, Sam
and suggestions on this document. Hartman, and Elwyn Davies for their comments and suggestions on this
document.
3.0 Local IPv6 Unicast Addresses 3.0 Local IPv6 Unicast Addresses
3.1 Format 3.1 Format
The Local IPv6 addresses are created using a pseudo-randomly The Local IPv6 addresses are created using a pseudo-randomly
allocated global ID. They have the following format: allocated global ID. They have the following format:
| 7 bits |1| 40 bits | 16 bits | 64 bits | | 7 bits |1| 40 bits | 16 bits | 64 bits |
+--------+-+------------+-----------+-----------------------------+ +--------+-+------------+-----------+-----------------------------+
| prefix |L| global ID | subnet ID | interface ID | | Prefix |L| Global ID | Subnet ID | Interface ID |
+--------+-+------------+-----------+-----------------------------+ +--------+-+------------+-----------+-----------------------------+
Where: Where:
prefix FC00::/7 prefix to identify Local IPv6 unicast Prefix FC00::/7 prefix to identify Local IPv6 unicast
addresses. addresses.
L Set to 1 if the prefix is locally assigned, L Set to 1 if the prefix is locally assigned.
Set to 0 if it is centrally assigned. See Set to 0 may be defined in the future. See
section 3.2 for additional information. section 3.2 for additional information.
global ID 40-bit global identifier used to create a Global ID 40-bit global identifier used to create a
globally unique prefix. See section 3.2 for globally unique prefix. See section 3.2 for
additional information. additional information.
subnet ID 16-bit subnet ID is an identifier of a subnet Subnet ID 16-bit Subnet ID is an identifier of a subnet
within the site. within the site.
interface ID 64-bit interface ID as defined in [ADDARCH]. Interface ID 64-bit Interface ID as defined in [ADDARCH].
3.1.1 Background 3.1.1 Background
There were a range of choices available when choosing the size of the There were a range of choices available when choosing the size of the
prefix and global ID field length. There is a direct tradeoff prefix and Global ID field length. There is a direct tradeoff
between having a global ID field large enough to support foreseeable between having a Global ID field large enough to support foreseeable
future growth and not using too much of the IPv6 address space future growth and not using too much of the IPv6 address space
needlessly. A reasonable way of evaluating a specific field length needlessly. A reasonable way of evaluating a specific field length
is to compare it to a projected 2050 world population of 9.3 billion is to compare it to a projected 2050 world population of 9.3 billion
[POPUL] and the number of resulting /48 prefixes per person. A range [POPUL] and the number of resulting /48 prefixes per person. A range
of prefix choices is shown in the following table: of prefix choices is shown in the following table:
Prefix Global ID Number of Prefixes % of IPv6 Prefix Global ID Number of Prefixes % of IPv6
Length /48 Prefixes per Person Address Space Length /48 Prefixes per Person Address Space
/11 37 137,438,953,472 15 0.049% /11 37 137,438,953,472 15 0.049%
/10 38 274,877,906,944 30 0.098% /10 38 274,877,906,944 30 0.098%
/9 39 549,755,813,888 59 0.195% /9 39 549,755,813,888 59 0.195%
/8 40 1,099,511,627,776 118 0.391% /8 40 1,099,511,627,776 118 0.391%
/7 41 2,199,023,255,552 236 0.781% /7 41 2,199,023,255,552 236 0.781%
/6 42 4,398,046,511,104 473 1.563% /6 42 4,398,046,511,104 473 1.563%
A very high utilization ratio of these allocations can be assumed A very high utilization ratio of these allocations can be assumed
because the global ID field does not require internal structure, and because the Global ID field does not require internal structure, and
there is no reason to be able to aggregate the prefixes. there is no reason to be able to aggregate the prefixes.
The authors believe that a /7 prefix resulting in a 40 bit global ID The authors believe that a /7 prefix resulting in a 41 bit Global ID
is a good choice. It provides for a large number of assignments space (including the L bit) is a good choice. It provides for a
(i.e., 2.2 trillion) and at the same time uses less than .8% of the large number of assignments (i.e., 2.2 trillion) and at the same time
total IPv6 address space. It is unlikely that this space will be uses less than .8% of the total IPv6 address space. It is unlikely
exhausted. If more than this were to be needed, then additional IPv6 that this space will be exhausted. If more than this were to be
address space could be allocated for this purpose. needed, then additional IPv6 address space could be allocated for
this purpose.
3.2 Global ID 3.2 Global ID
The allocation of global IDs should be pseudo-random [RANDOM]. They The allocation of Global IDs is pseudo-random [RANDOM]. They MUST
should not be assigned sequentially or with well known numbers. This NOT be assigned sequentially or with well known numbers. This is to
is to ensure that there is not any relationship between allocations ensure that there is not any relationship between allocations and to
and to help clarify that these prefixes are not intended to be routed help clarify that these prefixes are not intended to be routed
globally. Specifically, these prefixes are not designed to globally. Specifically, these prefixes are not designed to
aggregate. aggregate.
There are two ways to allocate Global IDs. These are centrally by a This document defines a specific local method to allocate Global IDs,
allocation authority and locally by the site. The type of allocation indicated by setting the L bit to 1. Another method, indicated by
is distinguished by the L bit. clearing the L bit, may be defined later. Apart from the allocation
method, all Local IPv6 addresses behave and are treated identically.
Two assignment methods are included because they have different
properties. The centrally assigned global IDs are uniquely assigned.
The local assignments are self generated and do not need any central The local assignments are self generated and do not need any central
coordination or assignment, but have a lower (but still adequate) coordination or assignment, but have an extremely high probability of
probability of being unique. It is expected that large managed sites being unique.
will prefer central assignments and small or disconnected sites will
prefer local assignments. It is recommended that sites planning to
use Local IPv6 addresses for extensive inter-site communication,
initially or as a future possibility, use a centrally assigned prefix
as there is no possibility of assignment conflicts. Sites are free
to choose either approach.
This document only defines the allocation procedure for creating
global-IDs for locally assigned local IPv6 addresses (i.e., L=1).
The allocation procedure for centrally assigned local IPv6 addresses
(i.e., L=0) will be defined in a separate document.
3.2.1 Locally Assigned Global IDs 3.2.1 Locally Assigned Global IDs
Global IDs can be generated locally by an individual site. This Locally assigned Global IDs MUST be generated with a pseudo-random
makes it easy to get a prefix without the need to contact an
assignment authority or internet service provider. There is not as
high a degree of assurance that the prefix will not conflict with
another locally generated prefix, but the likelihood of conflict is
small. Sites that are not comfortable with this degree of
uncertainty should use a centrally assigned global ID.
Locally assigned global IDs MUST be generated with a pseudo-random
algorithm consistent with [RANDOM]. Section 3.2.2 describes a algorithm consistent with [RANDOM]. Section 3.2.2 describes a
suggested algorithm. It is important to ensure a reasonable suggested algorithm. It is important that all sites generating
likelihood uniqueness that all sites generating a Global IDs use a Global IDs use a functionally similar algorithm to ensure there is a
functionally similar algorithm. high probability of uniqueness.
The use of a pseudo-random algorithm to generate global IDs in the The use of a pseudo-random algorithm to generate Global IDs in the
locally assigned prefix gives an assurance that any network numbered locally assigned prefix gives an assurance that any network numbered
using such a prefix is highly unlikely to have that address space using such a prefix is highly unlikely to have that address space
clash with any other network that has another locally assigned prefix clash with any other network that has another locally assigned prefix
allocated to it. This is a particularly useful property when allocated to it. This is a particularly useful property when
considering a number of scenarios including networks that merge, considering a number of scenarios including networks that merge,
overlapping VPN address space, or hosts mobile between such networks. overlapping VPN address space, or hosts mobile between such networks.
3.2.2 Sample Code for Pseudo-Random Global ID Algorithm 3.2.2 Sample Code for Pseudo-Random Global ID Algorithm
The algorithm described below is intended to be used for locally The algorithm described below is intended to be used for locally
skipping to change at page 6, line 35 skipping to change at page 6, line 25
cannot be obtained or created, a suitably unique identifier, cannot be obtained or created, a suitably unique identifier,
local to the node, should be used (e.g. system serial number). local to the node, should be used (e.g. system serial number).
3) Concatenate the time of day with the system-specific identifier 3) Concatenate the time of day with the system-specific identifier
creating a key. creating a key.
4) Compute an SHA-1 digest on the key as specified in [FIPS, SHA1]; 4) Compute an SHA-1 digest on the key as specified in [FIPS, SHA1];
the resulting value is 160 bits. the resulting value is 160 bits.
5) Use the least significant 40 bits as the Global ID. 5) Use the least significant 40 bits as the Global ID.
6) Concatenate FC00::/7, the L bit set to 1, and the 40 bit Global 6) Concatenate FC00::/7, the L bit set to 1, and the 40 bit Global
ID to create a Local IPv6 address prefix. ID to create a Local IPv6 address prefix.
This algorithm will result in a global ID that is reasonably unique This algorithm will result in a Global ID that is reasonably unique
and can be used to create a locally assigned local IPv6 address and can be used to create a locally assigned Local IPv6 address
prefix. prefix.
3.2.3 Analysis of the Uniqueness of Global IDs 3.2.3 Analysis of the Uniqueness of Global IDs
The selection of a pseudo random global ID is similar to the The selection of a pseudo random Global ID is similar to the
selection of an SSRC identifier in RTP/RTCP defined in section 8.1 of selection of an SSRC identifier in RTP/RTCP defined in section 8.1 of
[RTP]. This analysis is adapted from that document. [RTP]. This analysis is adapted from that document.
Since global IDs are chosen randomly (and independently), it is Since Global IDs are chosen randomly (and independently), it is
possible that separate networks have chosen the same global ID. For possible that separate networks have chosen the same Global ID. For
any given network with one or more random global IDs that has inter- any given network with one or more random Global IDs that has inter-
connections to other such networks, having a total of N such IDs, the connections to other such networks, having a total of N such IDs, the
probability of that two or more of these IDs will collide can be probability that two or more of these IDs will collide can be
approximated using the formula: approximated using the formula:
P = 1 - exp(-N**2 / 2**(L+1)) P = 1 - exp(-N**2 / 2**(L+1))
approximates the probability of collision (where N is the number where P is the probability of collision, N is the number of
connections and L is the length of the global ID). interconnected Global IDs, and L is the length of the Global ID.
The following table shows the probability of a collision for a range The following table shows the probability of a collision for a range
of connections using a 40 bit global ID field. of connections using a 40 bit Global ID field.
Connections Probability of Collision Connections Probability of Collision
2 1.81*10^-12 2 1.81*10^-12
10 4.54*10^-11 10 4.54*10^-11
100 4.54*10^-09 100 4.54*10^-09
1000 4.54*10^-07 1000 4.54*10^-07
10000 4.54*10^-05 10000 4.54*10^-05
Based on this analysis the uniqueness of locally generated global IDs Based on this analysis the uniqueness of locally generated Global IDs
is adequate for sites planning a small to moderate amount of inter- is adequate for sites planning a small to moderate amount of inter-
site communication using locally generated global IDs. Sites site communication using locally generated Global IDs.
planning more extensive inter-site communication should consider
using the centrally assigned global ID.
3.3 Scope Definition 3.3 Scope Definition
By default, the scope of these addresses is global. That is, they By default, the scope of these addresses is global. That is, they
are not limited by ambiguity like the site-local addresses defined in are not limited by ambiguity like the site-local addresses defined in
[ADDARCH]. Rather, these prefixes are globally unique, and as such, [ADDARCH]. Rather, these prefixes are globally unique, and as such,
their applicability is greater than site-local addresses. Their their applicability is greater than site-local addresses. Their
limitation is in the routability of the prefixes, which is limited to limitation is in the routability of the prefixes, which is limited to
a site and any explicit routing agreements with other sites to a site and any explicit routing agreements with other sites to
propagate them. Also, unlike site-locals, a site may have more than propagate them (also see section 4.1). Also, unlike site-locals, a
one of these prefixes and use them at the same time. site may have more than one of these prefixes and use them at the
same time.
4.0 Operational Guidelines 4.0 Operational Guidelines
The guidelines in this section do not require any change to the The guidelines in this section do not require any change to the
normal routing and forwarding functionality in an IPv6 host or normal routing and forwarding functionality in an IPv6 host or
router. These are configuration and operational usage guidelines. router. These are configuration and operational usage guidelines.
4.1 Routing 4.1 Routing
Local IPv6 addresses are designed to be routed inside of a site in Local IPv6 addresses are designed to be routed inside of a site in
the same manner as other types of unicast addresses. They can be the same manner as other types of unicast addresses. They can be
carried in any IPv6 routing protocol without any change. carried in any IPv6 routing protocol without any change.
It is expected that they would share the same subnet IDs with It is expected that they would share the same Subnet IDs with
provider based global unicast addresses if they were being used provider based global unicast addresses if they were being used
concurrently [GLOBAL]. concurrently [GLOBAL].
The default behavior of exterior routing protocol sessions between The default behavior of exterior routing protocol sessions between
administrative routing regions must be to ignore receipt of and not administrative routing regions must be to ignore receipt of and not
advertise prefixes in the FC00::/7 block. A network operator may advertise prefixes in the FC00::/7 block. A network operator may
specifically configure prefixes longer than FC00::/7 for inter-site specifically configure prefixes longer than FC00::/7 for inter-site
communication. communication.
If BGP is being used at the site border with an ISP, the default BGP If BGP is being used at the site border with an ISP, the default BGP
configuration must filter out any Local IPv6 address prefixes, both configuration must filter out any Local IPv6 address prefixes, both
incoming and outgoing. It must be set both to keep any Local IPv6 incoming and outgoing. It must be set both to keep any Local IPv6
address prefixes from being advertised outside of the site as well as address prefixes from being advertised outside of the site as well as
to keep these prefixes from being learned from another site. The to keep these prefixes from being learned from another site. The
exception to this is if there are specific /48 or longer routes exception to this is if there are specific /48 or longer routes
created for one or more Local IPv6 prefixes. created for one or more Local IPv6 prefixes.
For link-state IGPs, it is suggested that a site utilizing ULA For link-state IGPs, it is suggested that a site utilizing IPv6 local
prefixes be contained either within one IGP domain or area. By addresses prefixes be contained either within one IGP domain or area.
containing a ULA prefix to a single link-state area or domain, the By containing an IPv6 local address prefix to a single link-state
distribution of prefixes can be controlled. area or domain, the distribution of prefixes can be controlled.
4.2 Renumbering and Site Merging 4.2 Renumbering and Site Merging
The use of Local IPv6 addresses in a site results in making The use of Local IPv6 addresses in a site results in making
communication using these addresses independent of renumbering a communication using these addresses independent of renumbering a
site's provider based global addresses. site's provider based global addresses.
When merging multiple sites the addresses created with these prefixes When merging multiple sites the addresses created with these prefixes
are unlikely to need to be renumbered because all of the addresses are unlikely to need to be renumbered because all of the addresses
have a high probability of being unique. Routes for each specific have a high probability of being unique. Routes for each specific
prefix would have to be configured to allow routing to work correctly prefix would have to be configured to allow routing to work correctly
between the formerly separate sites. between the formerly separate sites.
4.3 Site Border Router and Firewall Packet Filtering 4.3 Site Border Router and Firewall Packet Filtering
While no serious harm will be done if packets with these addresses While no serious harm will be done if packets with these addresses
are sent outside of a site via a default route, it is recommended are sent outside of a site via a default route, it is recommended
that routers be configured by default to keep any packets with Local that routers be configured by default to keep any packets with Local
IPv6 destination addresses from leaking outside of the site and to IPv6 addresses from leaking outside of the site and to keep any site
keep any site prefixes from being advertised outside of their site. prefixes from being advertised outside of their site.
Site border routers should be configured to install a "reject" route
for the Local IPv6 prefix FC00::/7. This will ensure that packets
with Local IPv6 destination addresses will not be forwarded outside
of the site via a default route. Site border routers should respond
with the appropriate ICMPv6 Destination Unreachable message to inform
the source that the packet was not forwarded [ICMPV6]. This feedback
is important to avoid transport protocol timeouts.
Site border routers and firewalls should be configured to not forward Site border routers and firewalls should be configured to not forward
any packets with Local IPv6 source or destination addresses outside any packets with Local IPv6 source or destination addresses outside
of the site unless they have been explicitly configured with routing of the site unless they have been explicitly configured with routing
information about specific /48 or longer Local IPv6 prefixes. The information about specific /48 or longer Local IPv6 prefixes. This
will ensure that packets with Local IPv6 destination addresses will
not be forwarded outside of the site via a default route. The
default behavior of these devices should be to install a "reject" default behavior of these devices should be to install a "reject"
route for these prefixes. Site border routers should respond with route for these prefixes. Site border routers should respond with
the appropriate ICMPv6 Destination Unreachable message to inform the the appropriate ICMPv6 Destination Unreachable message to inform the
source that the packet was not forwarded. source that the packet was not forwarded. [ICMPV6]. This feedback is
important to avoid transport protocol timeouts.
Routers that maintain peering arrangements between Autonomous Systems Routers that maintain peering arrangements between Autonomous Systems
throughout the Internet should obey the recommendations for site throughout the Internet should obey the recommendations for site
border routers unless configured otherwise. border routers unless configured otherwise.
4.4 DNS Issues 4.4 DNS Issues
At the present time AAAA and PTR records for locally assigned local At the present time AAAA and PTR records for locally assigned local
IPv6 addresses are not recommended to be installed in the global DNS. IPv6 addresses are not recommended to be installed in the global DNS.
The operational issues relating to this are beyond the scope of this The operational issues relating to this are beyond the scope of this
document. document.
For background on this recommendation, the concern about adding AAAA For background on this recommendation, the concern about adding AAAA
and PTR records to the global DNS for locally assigned local IPv6 and PTR records to the global DNS for locally assigned Local IPv6
addresses stems from the lack of complete assurance that the prefixes addresses stems from the lack of complete assurance that the prefixes
are unique. There is a small possibility that the same PTR record are unique. There is a small possibility that the same PTR record
might be registered by two different organizations. Due to this might be registered by two different organizations. Due to this
concern, adding AAAA records is thought to be unwise because matching concern, adding AAAA records is thought to be unwise because matching
PTR records can not be registered PTR records can not be registered
4.5 Application and Higher Level Protocol Issues 4.5 Application and Higher Level Protocol Issues
Application and other higher level protocols can treat Local IPv6 Application and other higher level protocols can treat Local IPv6
addresses in the same manner as other types of global unicast addresses in the same manner as other types of global unicast
addresses. No special handling is required. This type of addresses addresses. No special handling is required. This type of address
may not be reachable, but that is no different from other types of may not be reachable, but that is no different from other types of
IPv6 global unicast addresses. Applications need to be able to IPv6 global unicast address. Applications need to be able to handle
handle multiple addresses that may or may not be reachable any point multiple addresses that may or may not be reachable at any point in
in time. In most cases this complexity should be hidden in APIs. time. In most cases this complexity should be hidden in APIs.
From a host's perspective this difference shows up as different From a host's perspective this difference shows up as different
reachability than global unicast and could be handled by default that reachability than global unicast and could be handled by default that
way. In some cases it is better for nodes and applications to treat way. In some cases it is better for nodes and applications to treat
them differently from global unicast addresses. A starting point them differently from global unicast addresses. A starting point
might be to give them preference over global unicast, but fall back might be to give them preference over global unicast, but fall back
to global unicast if a particular destination is found to be to global unicast if a particular destination is found to be
unreachable. Much of this behavior can be controlled by how they are unreachable. Much of this behavior can be controlled by how they are
allocated to nodes and put into the DNS. However it is useful if a allocated to nodes and put into the DNS. However it is useful if a
host can have both types of addresses and use them appropriately. host can have both types of addresses and use them appropriately.
skipping to change at page 10, line 23 skipping to change at page 10, line 10
Note that the address selection mechanisms of [ADDSEL], and in Note that the address selection mechanisms of [ADDSEL], and in
particular the policy override mechanism replacing default address particular the policy override mechanism replacing default address
selection, are expected to be used on a site where Local IPv6 selection, are expected to be used on a site where Local IPv6
addresses are configured. addresses are configured.
4.6 Use of Local IPv6 Addresses for Local Communication 4.6 Use of Local IPv6 Addresses for Local Communication
Local IPv6 addresses, like global scope unicast addresses, are only Local IPv6 addresses, like global scope unicast addresses, are only
assigned to nodes if their use has been enabled (via IPv6 address assigned to nodes if their use has been enabled (via IPv6 address
autoconfiguration [ADDAUTO], DHCPv6 [DHCP6], or manually). They are autoconfiguration [ADDAUTO], DHCPv6 [DHCP6], or manually). They are
not created automatically the way that IPv6 link-local addresses are not created automatically in the way that IPv6 link-local addresses
and will not appear or be used unless they are purposely configured. are and will not appear or be used unless they are purposely
configured.
In order for hosts to autoconfigure Local IPv6 addresses, routers In order for hosts to autoconfigure Local IPv6 addresses, routers
have to be configured to advertise Local IPv6 /64 prefixes in router have to be configured to advertise Local IPv6 /64 prefixes in router
advertisements, or a DHCPv6 server must have been configured to advertisements, or a DHCPv6 server must have been configured to
assign them. In order for a node to learn the Local IPv6 address of assign them. In order for a node to learn the Local IPv6 address of
another node, the Local IPv6 address must have been installed in the another node, the Local IPv6 address must have been installed in a
DNS or another naming system. For these reasons, it is straight naming system (e.g., DNS, proprietary naming system, etc.) For these
forward to control their usage in a site. reasons, it is straight forward to control their usage in a site.
To limit the use of Local IPv6 addresses the following guidelines To limit the use of Local IPv6 addresses the following guidelines
apply: apply:
- Nodes that are to only be reachable inside of a site: The local - Nodes that are to only be reachable inside of a site: The local
DNS should be configured to only include the Local IPv6 DNS should be configured to only include the Local IPv6
addresses of these nodes. Nodes with only Local IPv6 addresses addresses of these nodes. Nodes with only Local IPv6 addresses
must not be installed in the global DNS. must not be installed in the global DNS.
- Nodes that are to be limited to only communicate with other - Nodes that are to be limited to only communicate with other
skipping to change at page 11, line 24 skipping to change at page 11, line 14
4.7 Use of Local IPv6 Addresses with VPNs 4.7 Use of Local IPv6 Addresses with VPNs
Local IPv6 addresses can be used for inter-site Virtual Private Local IPv6 addresses can be used for inter-site Virtual Private
Networks (VPN) if appropriate routes are set up. Because the Networks (VPN) if appropriate routes are set up. Because the
addresses are unique these VPNs will work reliably and without the addresses are unique these VPNs will work reliably and without the
need for translation. They have the additional property that they need for translation. They have the additional property that they
will continue to work if the individual sites are renumbered or will continue to work if the individual sites are renumbered or
merged. merged.
5.0 Advantages and Disadvantages 5.0 Global Routing Considerations
5.1 Advantages Section 4.1 provides operational guidelines that forbid default
routing of local addresses between sites. Concerns were raised to
the IPv6 working group and to the IETF as a whole that sites may
attempt to use local addresses as globally routed provider-
independent addresses. This section describes why using local
addresses as globally-routed provider-independent addresses is
unadvisable.
5.1 From the Standpoint of the Internet
There is a mismatch between the structure of IPv6 local addresses and
the normal IPv6 wide area routing model. The /48 prefix of an IPv6
local addresses fits nowhere in the normal hierarchy of IPv6 unicast
addresses. Normal IPv6 unicast addresses can be routed
hierarchically down to physical subnet (link) level and only have to
be flat-routed on the physical subnet. IPv6 local addresses would
have to be flat-routed even over the wide area Internet.
Thus, packets whose destination address is an IPv6 local address
could be routed over the wide area only if the corresponding /48
prefix were carried by the wide area routing protocol in use, such as
BGP. This contravenes the operational assumption that long prefixes
will be aggregated into many fewer short prefixes, to limit the table
size and convergence time of the routing protocol. If a network uses
both normal IPv6 addresses [ADDARCH] and IPv6 local addresses, these
types of address will certainly not aggregate with each other, since
they differ from the most significant bit onwards. Neither will IPv6
local addresses aggregate with each other, due to their random bit
patterns. This means that there would be a very significant
operational penalty for attempting to use IPv6 local address prefixes
generically with currently known wide area routing technology.
5.2 From the Standpoint of a Site
There are a number of design factors in IPv6 local addresses that
reduce the likelihood that IPv6 local addresses will be used as
arbitrary global unicast addresses. These include:
- The default rules to filter packets and routes make it very
difficult to use IPv6 local addresses for arbitrary use across
the Internet. For a site to use them as general purpose unicast
addresses, they would have to make sure that the default rules
were not being used by all other sites and intermediate ISPs
used for their current and future communication.
- They are not mathematically guaranteed to be unique and are not
registered in public databases. Collisions, while highly
unlikely, are possible and a collision can compromise the
integrity of the communications. The lack of public
registration creates operational problems.
- The addresses are allocated randomly. If a site had multiple
prefixes that they wanted to be used globally the cost of
advertising them would be very high as they could not be
aggregated.
- They have a long prefix (i.e, /48) so a single local address
prefix doesn't provide enough address space to be used
exclusively by the largest organizations.
6.0 Advantages and Disadvantages
6.1 Advantages
This approach has the following advantages: This approach has the following advantages:
- Provides Local IPv6 prefixes that can be used independently of - Provides Local IPv6 prefixes that can be used independently of
any provider based IPv6 unicast address allocations. This is any provider based IPv6 unicast address allocations. This is
useful for sites not always connected to the Internet or sites useful for sites not always connected to the Internet or sites
that wish to have a distinct prefix that can be used to localize that wish to have a distinct prefix that can be used to localize
traffic inside of the site. traffic inside of the site.
- Applications can treat these addresses in an identical manner as - Applications can treat these addresses in an identical manner as
any other type of global IPv6 unicast addresses. any other type of global IPv6 unicast addresses.
skipping to change at page 11, line 43 skipping to change at page 13, line 4
that wish to have a distinct prefix that can be used to localize that wish to have a distinct prefix that can be used to localize
traffic inside of the site. traffic inside of the site.
- Applications can treat these addresses in an identical manner as - Applications can treat these addresses in an identical manner as
any other type of global IPv6 unicast addresses. any other type of global IPv6 unicast addresses.
- Sites can be merged without any renumbering of the Local IPv6 - Sites can be merged without any renumbering of the Local IPv6
addresses. addresses.
- Sites can change their provider based IPv6 unicast address - Sites can change their provider based IPv6 unicast address
without disrupting any communication using Local IPv6 addresses. without disrupting any communication using Local IPv6 addresses.
- Well known prefix that allows for easy filtering at site - Well known prefix that allows for easy filtering at site
boundary. boundary.
- Can be used for inter-site VPNs. - Can be used for inter-site VPNs.
- If accidently leaked outside of a site via routing or DNS, there - If accidently leaked outside of a site via routing or DNS, there
is no conflict with any other addresses. is no conflict with any other addresses.
5.2 Disadvantages 6.2 Disadvantages
This approach has the following disadvantages: This approach has the following disadvantages:
- Not possible to route Local IPv6 prefixes on the global Internet - Not possible to route Local IPv6 prefixes on the global Internet
with current routing technology. Consequentially, it is with current routing technology. Consequentially, it is
necessary to have the default behavior of site border routers to necessary to have the default behavior of site border routers to
filter these addresses. filter these addresses.
- There is a very low probability of non-unique locally assigned - There is a very low probability of non-unique locally assigned
global IDs being generated by the algorithm in section 3.2.3. Global IDs being generated by the algorithm in section 3.2.3.
This risk can be ignored for all practical purposes, but it This risk can be ignored for all practical purposes, but it
leads to a theoretical risk of clashing address prefixes. leads to a theoretical risk of clashing address prefixes.
6.0 Security Considerations 7.0 Security Considerations
Local IPv6 addresses do not provide any inherent security to the Local IPv6 addresses do not provide any inherent security to the
nodes that use them. They may be used with filters at site nodes that use them. They may be used with filters at site
boundaries to keep Local IPv6 traffic inside of the site, but this is boundaries to keep Local IPv6 traffic inside of the site, but this is
no more or less secure than filtering any other type of global IPv6 no more or less secure than filtering any other type of global IPv6
unicast addresses. unicast addresses.
Local IPv6 addresses do allow for address-based security mechanisms, Local IPv6 addresses do allow for address-based security mechanisms,
including IPsec, across end to end VPN connections. including IPsec, across end to end VPN connections.
7.0 IANA Considerations 8.0 IANA Considerations
The IANA is instructed to assign the FC00::/7 prefix for Unique Local The IANA is instructed to assign the FC00::/7 prefix for Unique Local
IPv6 unicast addresses. IPv6 unicast addresses.
8.0 References 9.0 References
8.1 Normative References 9.1 Normative References
[ADDARCH] Hinden, R., S. Deering, S., "IP Version 6 Addressing [ADDARCH] Hinden, R., S. Deering, S., "IP Version 6 Addressing
Architecture", RFC 3513, April 2003. Architecture", RFC 3513, April 2003.
[FIPS] "Federal Information Processing Standards Publication", [FIPS] "Federal Information Processing Standards Publication",
(FIPS PUB) 180-1, Secure Hash Standard, 17 April 1995. (FIPS PUB) 180-1, Secure Hash Standard, 17 April 1995.
[GLOBAL] Hinden, R., S. Deering, E. Nordmark, "IPv6 Global Unicast [GLOBAL] Hinden, R., S. Deering, E. Nordmark, "IPv6 Global Unicast
Address Format", RFC 3587, August 2003. Address Format", RFC 3587, August 2003.
skipping to change at page 13, line 21 skipping to change at page 14, line 28
[RANDOM] Eastlake, D. 3rd, S. Crocker, J. Schiller, "Randomness [RANDOM] Eastlake, D. 3rd, S. Crocker, J. Schiller, "Randomness
Recommendations for Security", RFC 1750, December 1994. Recommendations for Security", RFC 1750, December 1994.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, BCP14, March 1997. Requirement Levels", RFC 2119, BCP14, March 1997.
[SHA1] D. Eastlake 3rd, P. Jones, "US Secure Hash Algorithm 1 [SHA1] D. Eastlake 3rd, P. Jones, "US Secure Hash Algorithm 1
(SHA1)", RFC 3174, September 2001. (SHA1)", RFC 3174, September 2001.
8.2 Informative References 9.2 Informative References
[ADDAUTO] Thomson, S., T. Narten, "IPv6 Stateless Address [ADDAUTO] Thomson, S., T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 2462, December 1998. Autoconfiguration", RFC 2462, December 1998.
[ADDSEL] Draves, R., "Default Address Selection for Internet [ADDSEL] Draves, R., "Default Address Selection for Internet
Protocol version 6 (IPv6)", RFC 3484, February 2003. Protocol version 6 (IPv6)", RFC 3484, February 2003.
[DHCP6] Droms, R., et. al., "Dynamic Host Configuration Protocol [DHCP6] Droms, R., et. al., "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC3315, July 2003. for IPv6 (DHCPv6)", RFC3315, July 2003.
[POPUL] Population Reference Bureau, "World Population Data Sheet [POPUL] Population Reference Bureau, "World Population Data Sheet
of the Population Reference Bureau 2002", August 2002. of the Population Reference Bureau 2002", August 2002.
[RTP] Schulzrinne, H., S. Casner, R. Frederick, V. Jacobson, [RTP] Schulzrinne, H., S. Casner, R. Frederick, V. Jacobson,
"RTP: A Transport Protocol for Real-Time Applications" "RTP: A Transport Protocol for Real-Time Applications"
RFC3550, July 2003. RFC3550, July 2003.
9.0 Authors' Addresses 10.0 Authors' Addresses
Robert M. Hinden Robert M. Hinden
Nokia Nokia
313 Fairchild Drive 313 Fairchild Drive
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
phone: +1 650 625-2004 phone: +1 650 625-2004
email: bob.hinden@nokia.com email: bob.hinden@nokia.com
Brian Haberman Brian Haberman
Johns Hopkins University Johns Hopkins University
Applied Physics Lab Applied Physics Lab
11100 Johns Hopkins Road 11100 Johns Hopkins Road
Laurel, MD 20723 Laurel, MD 20723
USA USA
phone: +1 443 778 1319 phone: +1 443 778 1319
email: brian@innovationslab.net email: brian@innovationslab.net
10.0 Change Log 11.0 Change Log
Draft <draft-ietf-ipv6-unique-local-addr-09.txt>
o Removed all mention of centrally assigned IPv6 local address
addresses based on IESG comments. L=0 is left to be defined in
the future.
o Added new section titled "Global Routing Considerations" that
discusses the issues relating to why using these addresses for
general purpose unicast address on the global internet is not a
good idea.
o Several editorial changes.
Draft <draft-ietf-ipv6-unique-local-addr-08.txt> Draft <draft-ietf-ipv6-unique-local-addr-08.txt>
o Moved sections 4-10, into one new section 4.0 titled o Moved sections 4-10, into one new section 4.0 titled
"operational guidelines" to clarify the their scope. "operational guidelines" to clarify the their scope.
o Clarified routing requirements to make it clearer that these o Clarified routing requirements to make it clearer that these
prefixes should not be routed on the global Internet. prefixes should not be routed on the global Internet.
o Various editorial changes. o Various editorial changes.
Draft <draft-ietf-ipv6-unique-local-addr-07.txt> Draft <draft-ietf-ipv6-unique-local-addr-07.txt>
o Changed the format in section 3.1 in add a "L" (local/central) o Changed the format in section 3.1 in add a "L" (local/central)
skipping to change at page 15, line 28 skipping to change at page 16, line 38
document clearer. document clearer.
o Changed pseudo-random algorithm to use SHA-1 instead of MD5. o Changed pseudo-random algorithm to use SHA-1 instead of MD5.
o Moved [POPUL] to be an informative reference. o Moved [POPUL] to be an informative reference.
o Added paragraph in Routing section to discuss the use of IGPs. o Added paragraph in Routing section to discuss the use of IGPs.
o Various editorial changes. o Various editorial changes.
Draft <draft-ietf-ipv6-unique-local-addr-06.txt> Draft <draft-ietf-ipv6-unique-local-addr-06.txt>
o Clarify text to permit prefixes longer than /48 to be o Clarify text to permit prefixes longer than /48 to be
configured. configured.
o Changed text in section 7.0 to recommend that locally assigned o Changed text in section 7.0 to recommend that locally assigned
ULA addresses are not installed in the global DNS and removed IPv6 local addresses are not installed in the global DNS and
text about consequences of if they were installed in the global removed text about consequences of if they were installed in the
DNS. global DNS.
o Clarify the text in section 5.1 to state that there is a high o Clarify the text in section 5.1 to state that there is a high
probability that there will be no address conflict when probability that there will be no address conflict when
renumbering. renumbering.
o Several minor editorial changes. o Several minor editorial changes.
Draft <draft-ietf-ipv6-unique-local-addr-05.txt> Draft <draft-ietf-ipv6-unique-local-addr-05.txt>
o Removed the definition and technical requirements for centrally o Removed the definition and technical requirements for centrally
assigned local address. The Centrally assigned local addresses assigned local address. The Centrally assigned local addresses
will be defined in a separate document. This document defines will be defined in a separate document. This document defines
the specific prefixes to be used for centrally and locally the specific prefixes to be used for centrally and locally
assigned IPv6 local addresses, but only the locally assigned assigned IPv6 local addresses, but only the locally assigned
local addresses are defined here. local addresses are defined here.
Draft <draft-ietf-ipv6-unique-local-addr-04.txt> Draft <draft-ietf-ipv6-unique-local-addr-04.txt>
o Clarified text in section 3.2.1 that central assigned prefixes o Clarified text in section 3.2.1 that central assigned prefixes
should be assigned under the authority of a single allocation should be assigned under the authority of a single allocation
organization. organization.
o Added step to suggested pseudo-random algorithm that in the case o Added step to suggested pseudo-random algorithm that in the case
of centrally assigned prefixes the computed global IDs should be of centrally assigned prefixes the computed Global IDs should be
verified against the escrow. verified against the escrow.
o Added new text to section 3.2.2 that explains in more detail the o Added new text to section 3.2.2 that explains in more detail the
need for pseudo-random global IDs (i.e., avoid duplicate need for pseudo-random Global IDs (i.e., avoid duplicate
allocations). allocations).
o Rewrote section 7.0 to describe DNS AAAA and PTR records, and o Rewrote section 7.0 to describe DNS AAAA and PTR records, and
clarify when they might be installed in the global DNS. clarify when they might be installed in the global DNS.
o Various editorial changes. o Various editorial changes.
Draft <draft-ietf-ipv6-unique-local-addr-03.txt> Draft <draft-ietf-ipv6-unique-local-addr-03.txt>
o Removed requirement of a fee per central allocation and updated o Removed requirement of a fee per central allocation and updated
IANA considerations to reflect this. Rewrote text to focus on IANA considerations to reflect this. Rewrote text to focus on
the requirement to avoid hoarding of allocations. the requirement to avoid hoarding of allocations.
skipping to change at page 17, line 25 skipping to change at page 18, line 33
"Local IPv6 addresses". "Local IPv6 addresses".
o Several editorial changes. o Several editorial changes.
Draft <draft-hinden-ipv6-global-local-addr-01.txt> Draft <draft-hinden-ipv6-global-local-addr-01.txt>
o Added section on scope definition and updated application o Added section on scope definition and updated application
requirement section. requirement section.
o Clarified that, by default, the scope of these addresses is o Clarified that, by default, the scope of these addresses is
global. global.
o Renumbered sections and general text improvements o Renumbered sections and general text improvements
o Removed reserved global ID values o Removed reserved Global ID values
o Added pseudo code for local allocation submitted by Brian o Added pseudo code for local allocation submitted by Brian
Haberman and added him as an author. Haberman and added him as an author.
o Split Global ID values into centrally assigned and local o Split Global ID values into centrally assigned and local
assignments and added text to describe local assignments assignments and added text to describe local assignments
Draft <draft-hinden-ipv6-global-local-addr-00.txt> Draft <draft-hinden-ipv6-global-local-addr-00.txt>
o Initial Draft o Initial Draft
11. Disclaimer of Validity 12.0 Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
13.0 Disclaimer of Validity
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
12. Copyright Statement 14.0 Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
 End of changes. 62 change blocks. 
137 lines changed or deleted 217 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/