WDIFF

draft-ietf-ipngwg-addr-arch-00.txt --> draft-ietf-ipngwg-addr-arch-01.txt

IP Version 6 Addressing Architecture
<draft-ietf-ipngwg-addr-arch-00.txt>

<draft-ietf-ipngwg-addr-arch-01.txt>

Status of this Memo

This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet- Drafts as reference
material or to cite them other than as ``work in progress.''

To learn the current status of any Internet-Draft, please check the
``1id-abstracts.txt'' listing contained in the Internet- Drafts
Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net
(Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific
Rim).

This Internet Draft expires October 1, 1995.

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1.0 INTRODUCTION

This specification defines the addressing architecture of the IP Version
6 protocol. It includes a detailed description of the address formats
for IPv6 [IPV6].

The document editor editors would like to acknowledge the contributions of Paul Francis, Steve Deering,
Jim Bound, Brian Carpenter, Deborah Estrin, Peter Ford, Bob Gilligan,
Christian Huitema, Tony Li, Greg Minshall, Erik Nordmark, Yakov Rekhtor,
Bill Simpson, and Sue Thomson. Special mention is also given to Yakov Rekhtor, Tony Li,
Deborah Estrin, and Peter Ford for the current definition of region
addresses.

2.0 IPv6 ADDRESSING

IPv6 addresses are 128-bit identifiers for interfaces and sets of
interfaces. There are three types of addresses:

Unicast: Identifier An identifier for a single interface. Packets A packet sent to a
unicast address are is delivered to the interface identified
by that address.

Region: Identifier

Anycast: An identifier for a set of interfaces on the border of a
region. Packets (typically
belonging to different nodes). A packet sent to a region an
anycast address are is delivered to one interface in of the interfaces
identified by that region. address (the "nearest" one, according
to the routing protocols' measure of distance).

Multicast: Identifier An identifier for a set of interfaces (typically
belonging to different nodes). Packets A packet sent to a
multicast address
are is delivered to all interfaces
identified by that
multicast address.

There are no broadcast addresses in IPv6, their function being
superseded by multicast addresses.

In this document, fields in addresses are given a specific name, for
example "subscriber". When this name is used with the term "ID" for
identifier after the name (e.g., "subscriber ID"), it refers to the
contents of the named field. When it is used with the term "prefix"
(e.g. "subscriber prefix") it refers to all of the address up to and
including this field.

In IPv6, all zeros and all ones are legal values for any field, unless
specifically excluded. Specifically, prefixes may contain zero-valued

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fields or end in zeros.

2.1 Addressing Model

IPv6 Addresses of all types are assigned to interfaces, not nodes.
Since each interface belongs to a single node, any of that node's
interfaces' unicast addresses may be used as an identifier for the node.

An IPv6 unicast address refers to a single interface. A single
interface may be assigned multiple IPv6 addresses of any type (unicast,
region,
anycast, and multicast). There are two exceptions to this model. These
are:

1) A single address may be assigned to multiple physical interfaces if
the implementation treats the multiple physical interfaces as one
interface when presenting it to the internet layer. This is useful
for load-sharing over multiple physical interfaces.

2) Routers may have unnumbered interfaces (i.e., no IPv6 address
assigned to the interface) on point-to-point links to eliminate the
necessity to manually configure and advertise the addresses.
Addresses are not need for point-to-point interfaces on routers if
those interfaces are not to be used as the origins or destinations
of any IPv6 datagrams.

IPv6 continues the IPv4 model that a subnet is associated with one link.
Multiple subnets may be assigned to the same link.

2.2 Text Representation of Addresses

There are three conventional forms for representing IPv6 addresses as
text strings:

1. The preferred form is x:x:x:x:x:x:x:x, where the 'x's are the
hexadecimal values of the eight 16-bit pieces of the address.
Examples:

FEDC:BA98:7654:3210:FEDC:BA98:7654:3210

1080:0:0:8:800:200C:417A

1080:0:0:0:8:800:200C:417A

Note that it is not necessary to write the leading zeros in an
individual field, but there must be at least one numeral in every
field (except for the case described in 2.).

2. Due to the method of allocating certain styles of IPv6 addresses,

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it will be common for addresses to contain long strings of zero
bits. In order to make writing address containing zero bits easier
a special syntax is available to compress the zeros. The use of

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two "::" indicate multiple groups of 16-bits of zeros. For example
the multicast address:

FF01:0:0:0:0:0:0:43

may be represented as:

FF01::43

The "::" can only appear once in an address. The "::" can also be
used to compress the leading or trailing zeros in an address.

3. An alternative form that is sometimes more convenient when dealing
with a mixed environment of IPv4 and IPv6 nodes is
x:x:x:x:x:x:d.d.d.d, where the 'x's are the hexadecimal values of
the six high-order 16-bit pieces of the address, and the 'd's are
the decimal values of the four low-order 8-bit pieces of the
address (standard IPv4 representation). Examples:

0:0:0:0:0:0:0:13.1.68.3

0:0:0:0:0:0:FFFF:129.144.52.38

0:0:0:0:0:0:13.1.68.3

0:0:0:0:0:FFFF:129.144.52.38

or in compressed form:

::13.1.68.3

::FFFF:129.144.52.38

2.3 Address Type Representation

The specific type of an IPv6 address is indicated by the leading bits in
the address. The variable-length field comprising these leading bits is
called the Format Prefix (FP). The initial allocation of these prefixes
is as follows:

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Allocation Prefix Fraction of
(binary) Address Space
------------------------------- -------- -------------
Reserved 0000 0000 1/256
Reserved
Unassigned 0000 0001 1/256

Reserved for NSAP Allocation 0000 001 1/128
Reserved for IPX Allocation 0000 010 1/128

Reserved

Unassigned 0000 011 1/128
Reserved
Unassigned 0000 1 1/32
Reserved
Unassigned 0001 1/16
Reserved
Unassigned 001 1/8

Provider-Based Unicast Address 010 1/8

Reserved

Unassigned 011 1/8

Reserved for Neutral-Interconnect-
Based Unicast Addresses 100 1/8

Reserved

Unassigned 101 1/8
Reserved
Unassigned 110 1/8
Reserved
Unassigned 1110 1/16
Reserved
Unassigned 1111 0 1/32
Reserved
Unassigned 1111 10 1/64
Reserved
Unassigned 1111 110 1/128

Reserved

Unassigned 1111 1110 0 1/512

Link Local Use Addresses 1111 1110 10 1/1024
Site Local Use Addresses 1111 1110 11 1/1024

Multicast Addresses 1111 1111 1/256

Note: IPv6 Addresses with Embedded IPv4 Addresses (see section
2.4.7), the The "unspecified address" (see section 2.4.5), and 2.4.2), the loopback
address (see section 2.4.6), 2.4.3), and the IPv6 Addresses with Embedded
IPv4 Addresses (see section 2.4.4), are assigned out of the 0000
0000 format prefix space.

This allocation supports the direct allocation of provider addresses,
NSAP addresses, IPX addresses,
local use addresses, and multicast addresses. Space is reserved for
NSAP addresses, IPX addresses, and neutral-interconnect addresses. The
remainder of the address space is reserved unassigned for future use. This can
be used for expansion of existing use (e.g., additional provider
addresses,
IPX addresses, etc.) or new uses (e.g., separate locators and identifiers).
Fifteen percent of the address space is initially

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allocated. The

remaining 85% is reserved for future use.

Unicast addresses are distinguished from multicast addresses by the
value of the high-order octet of the addresses: a value of FF (11111111)
identifies an address as a multicast address; any other value identifies
an address as a unicast address. Region Anycast addresses are taken from the
unicast address space, and are not syntactically distinguishable from
unicast addresses.

2.4 Unicast Addresses

The IPv6 unicast address is contiguous bit-wise maskable, similar to
IPv4 addresses under Class-less Interdomain Routing [CIDR].

There are several forms of unicast address assignment in IPv6, including
the global provider based unicast address, the neutral-interconnect
unicast address, the NSAP address, the IPX hierarchical address, the
site-local-use address, the link-local-use address, and the IPv4-capable
host address. Additional addresses types can be defined in the future.

IPv6 nodes may have considerable or little knowledge of the internal
structure of the IPv6 address, depending on the role the node plays (for
instance, host versus router). At a minimum, a node may consider that
unicast addresses (including its own) have no internal structure:

| 128 bits |
+-----------------------------------------------------------------+
| node address |
+-----------------------------------------------------------------+

A slightly sophisticated host (but still rather simple) may additionally
be aware of subnet prefix(es) for the link(s) it is attached to, where
different addresses may have different values for n:

Still more sophisticated hosts may be aware of other hierarchical
boundaries in the unicast address. Though a very simple router may have
no knowledge of the internal structure of IPv6 unicast addresses,
routers will more generally have knowledge of one or more of the
hierarchical boundaries for the operation of routing protocols. The
known boundaries will differ from router to router, depending on what

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positions the router holds in the routing hierarchy.

2.4.1 Unicast Address Examples

An example of a Unicast address format which will likely to be common on
LANs and other environments where IEEE 802 MAC addresses are available
is:

Where the 48-bit Interface ID is an IEEE-802 MAC address. The use of
IEEE 802 MAC addresses as a interface ID is expected to be very common
in environments where nodes have an IEEE 802 MAC address. In other
environments, where IEEE 802 MAC addresses are not available, other
types of link layer addresses can be used, such as E.164 addresses, for
the interface ID.

The inclusion of a unique global interface identifier, such as an IEEE
MAC address, makes possible a very simple form of auto-configuration of
addresses. A node may discover a subnet ID by listening to General
Advertisement messages send by a router on its attached link(s), and
then fabricating a IPv6 address for itself by using its IEEE MAC address
as the interface ID on that subnet. The details of host auto-
configuration are described in [AUTO] and [DISC].

Another unicast address format example is where a site or organization
requires additional layers of internal hierarchy. In this example the
subnet ID is divided into an area ID and a subnet ID. Its format is:

This technique can be continued to allow a site or organization to add
additional layers of internal hierarchy. It may be desirable to use a an
interface ID smaller than a 48-bit IEEE 802 MAC address to allow more
space for the additional layers of internal hierarchy. These could be
interface IDs which are administratively created by the site or
organization.

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2.4.2 Provider-Based Global Unicast Addresses The global provider-based unicast Unspecified Address

The address 0:0:0:0:0:0:0:0 is called the unspecified address. It must
never be assigned as described in
[ASSN]. This assignment strategy is similar to assignment any node. It indicates the absence of IPv4
addresses under an address.
One example of its use is in the CIDR scheme [CIDR]. The Source Address field of any IPv6 global provider-based
unicast
datagrams sent by an initializing host before it has learned its own
address.

The unspecified address format is as follows:

The high-order part of the address is assigned to registries, who then
assign portions of the address space to providers, who then assign
portions of the address space to subscribers, etc.

The registry ID identifies the registry which assigns the provider
portion of the address. The term "registry prefix" refers to the high-
order part of the address up to and including the registry ID.

The provider ID identifies a specific provider which assigns the
subscriber portion of the address. The term "provider prefix" refers to
the high-order part of the address up to and including the provider ID.

The subscriber ID distinguishes among multiple subscribers attached to
the provider identified by the provider ID. The term "subscriber
prefix" refers to the high-order part of the address up to and including
the subscriber ID.

The subnet ID identifies a specific physical link. There can be
multiple subnets on the same physical link. A specific subnet can not
span multiple physical links. The term "subnet prefix" refers to the
high-order part of the address up to and including the subnet ID. The
group of nodes identified by the subnet ID must be attached to the same
link.

The interface ID identifies a single interface among the group of
interfaces identified by the subnet prefix.

2.4.3 NSAP Addresses

This mapping of NSAP address into IPv6 addresses is as follows:

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| 7 |1| 4 | 12 | 32 bits | 16 bits| 48 bits |
+-------+-+-----+-------+------------+--------+-------------------+
|0000001|G| AFC | IDI | Prefix | Area | ID |
+-------+-+-----+-------+------------+--------+-------------------+

The complete definition, motivation, and usage can be found in [NSAP].

2.4.4 Local-use IPv6 Unicast Addresses

There are two types of local-use unicast addresses defined. These are
Link-Local and Site-Local. The Link-Local is for use on a single link
and the Site-Local is for use in a single site. Link-Local addresses
have the following format:

| 10 |
| bits | n bits | 118-n bits |
+----------+-------------------------+----------------------------+
|1111111010| 0 | interface ID |
+----------+-------------------------+----------------------------+

Link-Local addresses are designed to be used for addressing on a single
link for purposes such as auto-address configuration or when no routers
are present.

Site-Local addresses have the following format:

| 10 |
| bits | n bits | m bits | 118-n-m bits |
+----------+---------+---------------+----------------------------+
|1111111011| 0 | subnet ID | interface ID |
+----------+---------+---------------+----------------------------+

Site-Local addresses may be used for sites or organizations that are not
(yet) connected to the global Internet. They do not need to request or
"steal" an address prefix from the global Internet address space. IPv6
site-local addresses can be used instead. When the organization
connects to the global Internet, it can then form global addresses by
replacing the site-local prefix with a subscriber prefix.

2.4.5 The Unspecified Address

The address 0:0:0:0:0:0:0:0 is called the unspecified address. It must
never be assigned to any node. It indicates the absence of an address.

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One example of its use is in the Source Address field of any IPv6
datagrams sent by an initializing host before it has learned its own
address.

The unspecified address must not be used must not be used as the destination address of
IPv6 datagrams or in IPv6 Routing Headers.

2.4.6

2.4.3 The Loopback Address

The unicast address 0:0:0:0:0:0:0:1 is called the loopback address. It
may be used by a node to send a IPv6 datagram to itself. It may never
be assigned to any interface.

The loopback address must not be used as the source address in IPv6
datagrams that are sent outside of a single node.

2.4.7

2.4.4 IPv6 Addresses with Embedded IPv4 Addresses

The IPv6 transition mechanisms [TMV6] include a technique for hosts and routers
to dynamically tunnel IPv6 packets over IPv4 routing infrastructure.
IPv6 nodes that utilize this technique are assigned special IPv6 unicast
addresses that carry an IPv4 address in the low-
order low-order 32-bits. This
type of address is termed an "IPv4-compatible IPv6 address" and has the
format:

| 80 bits | 16 | 32 bits |
+--------------------------------------+--------------------------+
|0000..............................0000|0000| IPv4 address |
+--------------------------------------+----+---------------------+

A second type of IPv6 address which holds an embedded IPv4 address is
also defined. This address is used to represent the addresses of IPv4-
only nodes (those that *do not* support IPv6) as IPv6 addresses. This
type of address is termed an "IPv4-mapped IPv6 address" and has the
format:

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| 80 bits | 16 | 32 bits |
+--------------------------------------+--------------------------+
|0000..............................0000|FFFF| IPv4 address |
+--------------------------------------+----+---------------------+

2.4.5 NSAP Addresses

This mapping of NSAP address into IPv6 addresses is as follows:

| 7 | 121 bits |
+-------+---------------------------------------------------------+
|0000001| to be defined |
+-------+---------------------------------------------------------+

The draft definition, motivation, and usage are under study [NSAP].

2.4.6 IPX Addresses

This mapping of IPX address into IPv6 addresses is as follows:

| 7 | 121 bits |
+-------+---------------------------------------------------------+
|0000010| to be defined |
+-------+---------------------------------------------------------+

The draft definition, motivation, and usage are under study.

2.4.7 Provider-Based Global Unicast Addresses

The global provider-based unicast address is assigned as described in
[ALLOC] and [ADDRF]. This assignment strategy is similar to assignment
of IPv4 addresses under the CIDR scheme [CIDR]. The IPv6 global
provider-based unicast address format is as follows:

| 80 125-m-n- |
| 3 | n bits | 16 m bits | 32 o bits |
+--------------------------------------+--------------------------+
|0000..............................0000|FFFF| IPv4 address p bits |
+--------------------------------------+----+---------------------+

The high-order part of the address is assigned to registries, who then

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2.5 Region Addresses

Region Addresses provide information abstraction for

assign portions of the purpose address space to providers, who then assign
portions of
network layer routing. A subgraph the address space to subscribers, etc.

The registry ID identifies the registry which assigns the provider
portion of an internet forms a "Region" with
an identifier called a "Region-ID" if all the following conditions are
satisfied.

1. Associated with each Region is a globally unique identifier called
a Region-ID. Syntactically, a Region-ID is a 128-bit IPv6 unicast address.

2. There is an address administration (at least one, but maybe
several) that is responsible for unicast The term "registry prefix" refers to the high-
order part of the address allocation for all up to and including the nodes within registry ID.

The provider ID identifies a specific provider which assigns the subgraph. A Region-ID is assigned by one such
administration out
subscriber portion of the address. The term "provider prefix" refers to
the high-order part of the unicast address block used up to and including the provider ID.

The subscriber ID distinguishes among multiple subscribers attached to
the provider identified by the
administration for unicast provider ID. The term "subscriber
prefix" refers to the high-order part of the address allocation within up to and including
the subgraph.

3. All subscriber ID.

The subnet ID identifies a specific physical link. There can be
multiple subnets on the routers in same physical link. A specific subnet can not
span multiple physical links. The term "subnet prefix" refers to the Region that connect
high-order part of the subgraph (or its
connected components) with address up to and including the rest subnet ID. The
group of nodes identified by the internet are called
"Border Routers". These Region Border Routers (or just Border
Routers) are preconfigured with subnet ID must be attached to the Region-ID. same
link.

The configuration
procedures are outside interface ID identifies a single interface among the scope group of
interfaces identified by the definition.

4. At least some subnet prefix.

2.4.8 Local-use IPv6 Unicast Addresses

There are two types of local-use unicast addresses defined. These are
Link-Local and Site-Local. The Link-Local is for use on a Region's Border Routers advertise into single link
and the
Region's routing system Site-Local is for use in a prefix that matches (in the sense of the
"longest match" algorithm) single site. Link-Local addresses
have the Region's Region-ID. In addition, following format:

Link-Local addresses are designed to be used for addressing on a
Region's Border Router single
link for purposes such as auto-address configuration or when no routers
are present.

Site-Local addresses have the following format:

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Site-Local addresses may advertise into be used for sites or organizations that are not
(yet) connected to the routing system a global Internet. They do not need to request or
"steal" an address prefix equal from the global Internet address space. IPv6
site-local addresses can be used instead. When the organization
connects to the Region-ID only (i.e., global Internet, it can then form global addresses by
replacing the site-local prefix with a host route).

5. If Region-IDs are used subscriber prefix.

2.5 Anycast Addresses

An IPv6 anycast address is an address that is assigned to specify transit policies (i.e., specify more than one
interface (typically belonging to different nodes), with the property
that a packet should pass through at least one node in a Region
identified by a particular Region Identifier), in order sent to an anycast address is routed to enforce
strict source routes, the Region Border Router must know the
Region-IDs of all other routers nearest
interface having that share a common link with address, according to the
router

Region routing protocols'
measure of distance.

Anycast addresses MUST NOT be used as a source are allocated from the unicast address in space, using
any IPv6
datagrams.

The Border Routers of the Region consider the Region-ID to be one of
their addresses, and will accept packets with defined unicast address formats. Thus, anycast addresses are
syntactically indistinguishable from unicast addresses. When a destination unicast
address
equal is assigned to the Region-ID. All more than one interface, thus turning it into an
anycast address, the nodes within each connected component to which the address is assigned must be
explicitly configured to know that forms it is an anycast address.

For any assigned anycast address, there is a Region, including Region Border Routers, are said longest address prefix P
that identifies the topological region in which all interfaces belonging
to be
"members that anycast address reside. Within the region identified by P, each
member of the region".

Region-IDs can anycast set must be used to represent Routing Domains, Routing Domain
Confederations, OSPF areas, Subnets, as well advertised as generic anycast
addresses. This is described a separate entry in the
routing system (commonly referred to as follows:

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1. A Routing Domain is a Region. The domain is "host route"); outside the
region identified by a
Routing Domain Identifier (RDI), which is simply P, the Region-
Identifier anycast address may be aggregated into the
routing advertisement for prefix P.

Note that in, the domain. Any Border Router worst case, the prefix P of a domain is a
Region Border Router.

2. A Routing Domain Confederation is a Region. The confederation is
identified by a Routing Domain Confederation Identifier (RDCI),
which is an anycast set may be the Region Identifier for
null prefix, i.e., the confederation. A Border
Router members of a domain within a confederation that peers with a Border
Router in a domain that is not in the confederation is a Region
Border Router. set may have no topological
locality. In the case of confederations, note that all Border
Routers of domains nested within a confederation case, the anycast address must be configured
with the Region-IDs of advertised as a
separate routing entry throughout the confederation(s) in entire internet, which they are
nested.

3. An OSPF area is presents a Region. The Region Identifier of
severe scaling limit on how many such a Region "global" anycast sets may be any unicast address that matches address prefixes within the
area. Note
supported. Therefore, it is expected that OSPF area Border Routers do not need to support for global anycast
sets may be
configured with unavailable or very restricted.

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One expected use of anycast addresses is to identify the Region-ID set of their containing domain.

4. An routers
belonging to an internet service provider. Such addresses could be used
as intermediate addresses in an IPv6 subnet is Routing header, to cause a Region. The Region includes all the nodes
attached packet
to be delivered via a particular provider or sequence of providers.
Some other possible uses are to identify the subnet. Any router set of routers attached to the subnet is
a
Region Border Router. The Region-ID is an address out of particular subnet, or the
subnet.

5. A set of nodes that wish to share an anycast address can be
represented by routers providing entry into a Region-ID where each element
particular routing domain.

There is little experience with widespread, arbitrary use of internet
anycast addresses, and some known complications and hazards when using
them in their full generality [ANYCST]. Until more experience has been
gained and solutions agreed upon for those problems, the following
restrictions are imposed on IPv6 anycast group
is configured addresses:

o An anycast address MUST NOT be used as a Border Router for that Region. Note that
unconstrained usage the source address of an
IPv6 packet.

o An anycast addresses can lead address MUST NOT be assigned to scaling
problems. an IPv6 host, that is,
it may be assigned to an IPv6 router only.

2.6 Multicast Addresses

A IPv6 multicast address is an identifier for a group of nodes. A node
may belong to any number of multicast groups. Multicast addresses have
the following format:

| 8 | 4 | 4 | 112 bits |
+------ -+----+----+---------------------------------------------+
|11111111|flgs|scop| group ID |
+--------+----+----+---------------------------------------------+

11111111 at the start of the address identifies the address as
being a multicast address.

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+-+-+-+-+
flgs is a set of 4 flags: |0|0|0|T|
+-+-+-+-+

The high-order 3 flags are reserved, and must be initialized
to 0.

T = 0 indicates a permanently-assigned ("well-known")
multicast address, assigned by the global internet numbering
authority.

T = 1 indicates a non-permanently-assigned ("transient")
multicast address.

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scop is a 4-bit multicast scope value used to limit the scope of
the multicast group. The values are:

0 reserved
1 node-local scope
2 link-local scope
3 (unassigned)
4 (unassigned)
5 site-local scope
6 (unassigned)
7 (unassigned)
8 organization-local scope
9 (unassigned)
A (unassigned)
B community-local scope
C (unassigned)
D (unassigned)
E global scope
F reserved

group ID identifies the multicast group, either permanent or
transient, within the given scope.

The "meaning" of a permanently-assigned multicast address is independent
of the scope value. For example, if the "NTP servers group" is assigned
a permanent multicast address with a group ID of 43 (hex), then:

FF01:0:0:0:0:0:0:43 means all NTP servers on the same node as the
sender.

FF02:0:0:0:0:0:0:43 means all NTP servers on the same link as the
sender.

FF05:0:0:0:0:0:0:43 means all NTP servers at the same site as the

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INTERNET-DRAFT IPv6 Addressing Architecture March 1995
sender.

FF0E:0:0:0:0:0:0:43 means all NTP servers in the internet.

Non-permanently-assigned multicast addresses are meaningful only within
a given scope. For example, a group identified by the non-permanent,
site-local multicast address FF15:0:0:0:0:0:0:43 at one site bears no
relationship to a group using the same address at a different site, nor
to a non-permanent group using the same group ID with different scope,
nor to a permanent group with the same group ID.

Multicast addresses must not be used as source addresses in IPv6
datagrams or appear in any routing header.

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2.6.1 Pre-Defined Multicast Addresses

The following well-known multicast addresses are pre-defined:

Reserved Multicast Addresses: FF00:0:0:0:0:0:0:0
FF01:0:0:0:0:0:0:0
FF02:0:0:0:0:0:0:0
FF03:0:0:0:0:0:0:0
FF04:0:0:0:0:0:0:0
FF05:0:0:0:0:0:0:0
FF06:0:0:0:0:0:0:0
FF07:0:0:0:0:0:0:0
FF08:0:0:0:0:0:0:0
FF09:0:0:0:0:0:0:0
FF0A:0:0:0:0:0:0:0
FF0B:0:0:0:0:0:0:0
FF0C:0:0:0:0:0:0:0
FF0D:0:0:0:0:0:0:0
FF0E:0:0:0:0:0:0:0
FF0F:0:0:0:0:0:0:0

The above multicast addresses are reserved and shall never be assigned
to any multicast group.

All Nodes Addresses: FF01:0:0:0:0:0:0:1
FF02:0:0:0:0:0:0:1

The above multicast addresses identify the group of all IPv6 nodes,
within scope 1 (node-local) or 2 (link-local).

All Hosts Routers Addresses: FF01:0:0:0:0:0:0:2
FF02:0:0:0:0:0:0:2

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INTERNET-DRAFT IPv6 Addressing Architecture March 1995

The above multicast addresses identify the group of all IPv6 hosts, routers,
within scope 1 (node-local) or 2 (link-local).

All Routers Hosts Addresses: FF01:0:0:0:0:0:0:3
FF02:0:0:0:0:0:0:3

The above multicast addresses identify the group of all IPv6 routers, hosts,
within scope 1 (node-local) or 2 (link-local).

2.7 A Node's Required Addresses

A host is required to recognize the following addresses as identifying
itself:

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INTERNET-DRAFT IPv6 Addressing Architecture March 1995

o Assigned Unicast Addresses
o Loopback Address
o All Nodes Multicast Address
o All Hosts Multicast Address
o All other Multicast Addresses to which the host belongs.

A router is required to recognize the following addresses as identifying
itself:

o Assigned Unicast Addresses
o Region Addresses of all configured regions for Loopback Address
o All anycast addresses with which the router is
a boundary router
o Loopback Address has been configured.
o All Nodes Multicast Address
o All Router Multicast Address
o All other Multicast Addresses to which the router belongs.

The only address-prefixes which should be predefined in an
implementation are the:

o Unspecified Address
o Loopback Address
o Multicast prefix (FF)
o Pre-Defined Multicast Addresses
o IPv4 Compatible Prefixes

Implementations should assume all other addresses are unicast unless
specifically configured (e.g., region anycast addresses).

3.0 ROUTING ALGORITHMS

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INTERNET-DRAFT IPv6 Addressing Architecture March 1995

IPv6 routing algorithms are identical to those used with the CIDR
version of IP, except that the address used is 128 bits rather than 32
(for instance [OSPF], [RIP_]).

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INTERNET-DRAFT IPv6 Addressing Architecture March 1995

REFERENCES

[ASSN] Yakov

[ADDRF] Rekhter, "IPv6 Provider Y., Lothberg, P., "An IPv6 Global Unicast Address Assignment",
Format", Internet Draft.

[AUTO] S. Thomson, "Automatic Host Draft

[ALLOC] Rekhter, Y., Li, T., "An Architecture for IPv6 Unicast Address Assignment in IPv6",
Allocation", Internet Draft. Draft

[ANYCST]C. Partridge, T. Mendez, and W. Milliken, "Host Anycasting
Service", RFC-1546, November 1993.

[CIDR] V. Fuller, T. Li, K. Varadhan, J. Yu, "Supernetting: an
Address Assignment and Aggregation Strategy", RFC 1338.

[DISC] W. Simpson, "IPv6 Neighbor Discovery -- ICMP Message Formats",
Internet Draft.

[ICMP]

[IPV6] S. Deering, A. Conta, "ICMP and IGMP for the Internet Protocol
Version 6 (IPv6)" Internet-Draft.

[IPV6] R. Hinden, Editor, Editors, "Internet Protocol, Version 6
(IPv6) Specification", Internet Draft.

[MULT] S. Deering, "Host Extensions for IP multicasting", RFC 1112.

[NSAP] B. Carpenter, J. Bound, "Recommendations B.Carpenter, Editor, "Mechanisms for OSI NSAP usage in NSAPs, CLNP and TP
over IPv6", Internet Draft.

[OSPF] "OSPF for IPv6", Internet Draft, In preparation.

[RIP_] "RIPv2 for IPv6, Internet Draft, In preparation.

[TMV6] R. Gilligan, E. Nordmark, "Transition Mechanisms for IPv6
Hosts and Routers," Internet-Draft.

DOCUMENT EDITOR'S ADDRESS

Robert M. Hinden Stephen E. Deering
Ipsilon Network, Networks, Inc. Xerox Palo Alto Research Center
2465 Latham Street Street, Suite 100 3333 Coyote Hill Road
Mt. View, CA 94040 Palo Alto, CA 94304
USA

Phone: (415) 528-4604
FAX: (415) 854-4653
Email: USA

phone: +1 415 528 4604 phone: +1 415 812 4839
fax: +1 415 528 4653 fax: +1 415 812 4471
email: hinden@ipsilon.com

draft-ietf-ipngwg-ipv6-addr-arch-00.txt email: deering@parc.xerox.com

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APPENDIX

Changes from Previous Version

This version of the "IPv6 Addressing Architecture" includes the
following changes made since the previous version:

o Added "Addressing Model" section.

o Changed "Node ID" to "Interface ID" to reflect the current
Addressing Model.

o Cluster Address replaced by Region Address.

o Geographic Addresses changed to be Neutral-Interconnect
Addresses. addresses replace by Anycast addresses.

o Changed multicast scope names from inter-*** Reduced references to ***-local
style.

o Added mention that address subfields can be assigned a zero or
ones value. other documents.

o Reduced Reordered the amount address space assigned to local use and
divided unicast sections of the local use address space into link-local and site-
local unicast. document.

o Swapped prefixes for IPv4-compatible Changed Multicast All Routers and All Hosts to be consistent
with IPv4 mapped
addresses.

o Changed definition of loopback address.

o Added wording about wired in knowledge of address prefixes. multicast assignment.

o Minor clarification's, corrections, and typos fixed.

o New typos likely added.

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