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... architecture of the IP
Version 6 protocol. It includes the basic formats for the various
types of IPv6 addresses (unicast, anycast, and multicast ...
... interface" is as defined in Section 2 of [IPV6]).
There are three types of addresses:
Unicast ...
... identifier for a single interface. A packet sent to a
unicast address is delivered to the interface identified
by that address ...
... belonging to different nodes). A packet sent to an
anycast address is delivered to one of the interfaces
identified by that address ...
... anycast address is delivered to one of the interfaces
identified by that address (the "nearest" one, according
to the routing protocols' measure of distance).
...
... belonging to different nodes). A packet sent to a
multicast address is delivered to all interfaces
identified by that address ...
... multicast address is delivered to all interfaces
identified by that address.
There are no broadcast ...
...
There are no broadcast addresses in IPv6, their function being
superseded by multicast addresses ...
... addresses in IPv6, their function being
superseded by multicast addresses.
In this document, fields in addresses ...
... multicast addresses.
In this document, fields in addresses are given a specific name, for
example, "subnet". When this name is used with the term "ID" for
...
... prefix"
(e.g., "subnet prefix"), it refers to all of the address from the
left up to and including this field.
...
... All interfaces are required to have at least one Link-Local unicast
address (see Section 2.8 for additional required addresses). A
single interface ...
... interfaces are required to have at least one Link-Local unicast
address (see Section 2.8 for additional required addresses). A
single interface may also have multiple IPv6 addresses ...
... addresses). A
single interface may also have multiple IPv6 addresses of any type
(unicast, anycast ...
... unicast, anycast, and multicast) or scope. Unicast addresses with a
scope greater than link-scope are not needed for interfaces ...
... addressing model:
A unicast address or a set of unicast addresses may be assigned to
multiple physical interfaces ...
...
A unicast address or a set of unicast addresses may be assigned to
multiple physical interfaces if the implementation treats the
...
... 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 one to
four hexadecimal digits of the eight 16-bit pieces of the address.
Examples:
...
...
2. Due to some methods of allocating certain styles of IPv6
addresses, it will be common for addresses to contain long strings
of zero bits ...
... 2. Due to some methods of allocating certain styles of IPv6
addresses, it will be common for addresses to contain long strings
of zero bits. In order to make writing addresses ...
... addresses to contain long strings
of zero bits. In order to make writing addresses containing zero
bits easier, a special syntax is available to compress the zeros.
...
... groups of 16 bits of zeros.
The "::" can only appear once in an address. The "::" can also be
used to compress leading or trailing zeros in an address.
...
... The "::" can only appear once in an address. The "::" can also be
used to compress leading or trailing zeros in an address.
For example, the following addresses ...
... address.
For example, the following addresses
2001:DB8:0:0:8:800:200C:417A a unicast address ...
... addresses
2001:DB8:0:0:8:800:200C:417A a unicast address
FF01:0:0:0:0:0:0:101 a multicast address
...
... 2001:DB8:0:0:8:800:200C:417A a unicast address
FF01:0:0:0:0:0:0:101 a multicast address
0:0:0:0:0:0:0:1 the loopback address ...
... multicast address
0:0:0:0:0:0:0:1 the loopback address
0:0:0:0:0:0:0:0 the unspecified address
...
... may be represented as
2001:DB8::8:800:200C:417A a unicast address
FF01::101 a multicast address
...
... 2001:DB8::8:800:200C:417A a unicast address
FF01::101 a multicast address
::1 the loopback address ...
... loopback address
:: the unspecified address
3. An alternative form that is sometimes more convenient when dealing
...
... 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 ...
... the decimal values of the four low-order 8-bit pieces of the
address (standard IPv4 representation). Examples:
...
... Text Representation of Address Prefixes ...
... IPv6 address prefixes is similar to the
way IPv4 address prefixes are written in Classless Inter-Domain
Routing (CIDR ...
... Classless Inter-Domain
Routing (CIDR) notation [CIDR]. An IPv6 address prefix is
represented by the notation:
...
... represented by the notation:
ipv6-address/prefix-length
...
... where
ipv6-address is an IPv6 address in any of the notations listed
in Section 2.2.
...
...
ipv6-address is an IPv6 address in any of the notations listed
in Section 2.2.
...
... prefix-length is a decimal value specifying how many of the
leftmost contiguous bits of the address comprise
the prefix.
...
... 2001:0DB8:0:CD3/60 may drop leading zeros, but not trailing
zeros, within any 16-bit chunk of the address
2001:0DB8::CD30/60 address ...
... address
2001:0DB8::CD30/60 address to left of "/" expands to
2001:0DB8:0000:0000:0000:0000:0000:CD30
...
... 2001:0DB8:0000:0000:0000:0000:0000:CD30
2001:0DB8::CD3/60 address to left of "/" expands to
2001:0DB8:0000:0000:0000:0000:0000:0CD3
...
...
the node address 2001:0DB8:0:CD30:123:4567:89AB:CDEF
and its subnet number 2001:0DB8:0:CD30::/60
...
... Address Type Identification ...
... Global Unicast (everything else)
Anycast addresses are taken from the unicast address spaces (of any
scope) and are not syntactically distinguishable from unicast
addresses ...
...
Anycast addresses are taken from the unicast address spaces (of any
scope) and are not syntactically distinguishable from unicast
addresses.
...
... Anycast addresses are taken from the unicast address spaces (of any
scope) and are not syntactically distinguishable from unicast
addresses.
The general format ...
... The general format of Global Unicast addresses is described in
Section 2.5.4. Some special-purpose subtypes of Global Unicast
...
... Section 2.5.4. Some special-purpose subtypes of Global Unicast
addresses that contain embedded IPv4 addresses (for the purposes of
IPv4 ...
... Global Unicast
addresses that contain embedded IPv4 addresses (for the purposes of
IPv4-IPv6 ...
... Global Unicast space for other purposes, but unless and until that
happens, implementations must treat all addresses that do not start
with any of the above-listed prefixes ...
... Unicast Addresses ...
... prefixes of arbitrary
bit-length, similar to IPv4 addresses under Classless Inter-Domain
Routing.
...
... Classless Inter-Domain
Routing.
There are several types of unicast addresses in IPv6, in particular,
Global Unicast ...
... unicast. There are also some special-purpose subtypes
of Global Unicast, such as IPv6 addresses with embedded IPv4
addresses. Additional address types or subtypes can be defined in
...
... of Global Unicast, such as IPv6 addresses with embedded IPv4
addresses. Additional address types or subtypes can be defined in
the future.
...
... Global Unicast, such as IPv6 addresses with embedded IPv4
addresses. Additional address types or subtypes 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
...
... router). At a minimum, a node may
consider that unicast addresses (including its own) have no internal
structure:
...
... +-----------------------------------------------------------------+
| node address |
+-----------------------------------------------------------------+
...
... subnet prefix(es) for the link(s) it is
attached to, where different addresses may have different values for
n:
...
... 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
...
... previous paragraphs, nodes should not make any assumptions about the
structure of an IPv6 address.
...
... identifier will be
derived directly from that interface's link-layer address. The same
interface identifier may be used on multiple interfaces ...
... Note that the uniqueness of interface identifiers is independent of
the uniqueness of IPv6 addresses. For example, a Global Unicast
address ...
... IPv6 addresses. For example, a Global Unicast
address may be created with a local scope interface identifier and a
...
... created with a local scope interface identifier and a
Link-Local address may be created with a universal scope interface
identifier.
...
... interface
identifier.
For all unicast addresses, except those that start with the binary
value 000, Interface ...
... 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 ...
...
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
...
... must never be assigned to any node. It indicates the absence of an
address. One example of its use is in the Source Address field of
any IPv6 packets ...
... node. It indicates the absence of an
address. One example of its use is in the Source Address field of
any IPv6 packets sent by an initializing host ...
... IPv6 packets sent by an initializing host before it has learned
its own address.
The unspecified address ...
... address.
The unspecified address must not be used as the destination address
of IPv6 packets ...
...
The unspecified address must not be used as the destination address
of IPv6 packets or in IPv6 Routing ...
... headers. An IPv6 packet with a
source address of unspecified must never be forwarded by an IPv6
router ...
... 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 an IPv6 packet ...
... Link-Local scope, and may be thought of as the Link-Local unicast
address of a virtual interface (typically called the "loopback
interface") to an imaginary link ...
...
The loopback address must not be used as the source address in IPv6
packets that are sent outside of a single node ...
... The loopback address must not be used as the source address in IPv6
packets that are sent outside of a single node. An IPv6 packet ...
... node. An IPv6 packet with
a destination address of loopback must never be sent outside of a
single node ...
... router. A packet
received on an interface with a destination address of loopback must
be dropped.
...
... Global Unicast Addresses ...
... interface ID field (i.e., n + m = 64), formatted as
described in Section 2.5.1. Global Unicast addresses that start with
binary 000 have no such constraint ...
... addresses that start with binary 000 are
the IPv6 address with embedded IPv4 addresses described in Section
2.5.5. An example of global addresses ...
... start with binary 000 are
the IPv6 address with embedded IPv4 addresses described in Section
2.5.5. An example of global addresses starting ...
... IPv6 address with embedded IPv4 addresses described in Section
2.5.5. An example of global addresses starting with a binary value
other than 000 (and therefore having a 64-bit ...
... IPv6 Addresses with Embedded IPv4 Addresses ...
... IPv6 Addresses with Embedded IPv4 Addresses ...
...
Two types of IPv6 addresses are defined that carry an IPv4 address in
the low-order 32 bits of the address ...
... IPv4 address in
the low-order 32 bits of the address. These are the "IPv4-Compatible
IPv6 address ...
... IPv4-Compatible IPv6 Address ...
...
The "IPv4-Compatible IPv6 address" was defined to assist in the IPv6
transition. The format of the "IPv4-Compatible IPv6 address ...
... IPv6 address" was defined to assist in the IPv6
transition. The format of the "IPv4-Compatible IPv6 address" is as
follows:
...
... 32 bits |
+--------------------------------------+--------------------------+
|0000..............................0000|0000| IPv4 address |
+--------------------------------------+----+---------------------+
...
... +--------------------------------------+----+---------------------+
Note: The IPv4 address used in the "IPv4-Compatible IPv6 address"
...
... Note: The IPv4 address used in the "IPv4-Compatible IPv6 address"
must be a globally-unique IPv4 unicast address ...
...
The "IPv4-Compatible IPv6 address" is now deprecated because the
current IPv6 transition mechanisms no longer use these addresses ...
... IPv6 address" is now deprecated because the
current IPv6 transition mechanisms no longer use these addresses.
New or updated implementations are not required to support this
address type ...
... addresses.
New or updated implementations are not required to support this
address type.
...
... IPv4-Mapped IPv6 Address ...
...
A second type of IPv6 address that holds an embedded IPv4 address is
defined. This address type ...
...
A second type of IPv6 address that holds an embedded IPv4 address is
defined. This address type is used to represent the addresses ...
... IPv6 address that holds an embedded IPv4 address is
defined. This address type is used to represent the addresses of
IPv4 nodes ...
... IPv4 address is
defined. This address type is used to represent the addresses of
IPv4 nodes as IPv6 addresses ...
... addresses of
IPv4 nodes as IPv6 addresses. The format of the "IPv4-mapped IPv6
address" is as follows:
...
... IPv4 nodes as IPv6 addresses. The format of the "IPv4-mapped IPv6
address" is as follows:
| 80 bits ...
... 32 bits |
+--------------------------------------+--------------------------+
|0000..............................0000|FFFF| IPv4 address |
+--------------------------------------+----+---------------------+
...
...
Link-Local addresses are for use on a single link. Link-Local
addresses have the following format:
...
... Link-Local addresses are for use on a single link. Link-Local
addresses have the following format:
| 10 |
...
... +----------+-------------------------+----------------------------+
Link-Local addresses are designed to be used for addressing on a
single link ...
... addressing on a
single link for purposes such as automatic address configuration,
neighbor discovery, or when no routers ...
... Routers must not forward any packets with Link-Local source or
destination addresses to other links.
...
...
Site-Local addresses were originally designed to be used for
addressing inside of a site without the need for a global prefix ...
... addressing inside of a site without the need for a global prefix.
Site-local addresses are now deprecated as defined in [SLDEP].
...
... SLDEP].
Site-Local addresses have the following format:
| 10 |
...
... Anycast Addresses ...
... An IPv6 anycast address is an address that is assigned to more than
one interface (typically belonging to different nodes ...
... interface (typically belonging to different nodes), with the
property that a packet sent to an anycast address is routed to the
"nearest" interface having that address ...
... anycast address is routed to the
"nearest" interface having that address, according to the routing
protocols' measure of distance.
...
... routing
protocols' measure of distance.
Anycast addresses are allocated from the unicast address space, using
any of the defined unicast address ...
...
Anycast addresses are allocated from the unicast address space, using
any of the defined unicast address formats. Thus, anycast addresses ...
... Anycast addresses are allocated from the unicast address space, using
any of the defined unicast address formats. Thus, anycast addresses
are syntactically indistinguishable from unicast addresses ...
... unicast address space, using
any of the defined unicast address formats. Thus, anycast addresses
are syntactically indistinguishable from unicast addresses. When a
...
... unicast address formats. Thus, anycast addresses
are syntactically indistinguishable from unicast addresses. When a
unicast address is assigned to more than one interface ...
... are syntactically indistinguishable from unicast addresses. When a
unicast address is assigned to more than one interface, thus turning
it into an anycast address ...
... unicast address is assigned to more than one interface, thus turning
it into an anycast address, the nodes to which the address is
...
... it into an anycast address, the nodes to which the address is
assigned must be explicitly configured to know that it is an anycast
address.
...
... nodes to which the address is
assigned must be explicitly configured to know that it is an anycast
address.
For any assigned anycast address ...
... anycast
address.
For any assigned anycast address, there is a longest prefix P of that
address ...
... anycast address, there is a longest prefix P of that
address that identifies the topological region in which all
interfaces belonging to that anycast address ...
... address that identifies the topological region in which all
interfaces belonging to that anycast address reside. Within the
region identified by P, the anycast address must be maintained as a
...
... interfaces belonging to that anycast address reside. Within the
region identified by P, the anycast address must be maintained as a
separate entry in the routing system (commonly referred to as a "host ...
... host
route"); outside the region identified by P, the anycast address may
be aggregated into the routing entry for prefix ...
... the null prefix, i.e., the members of the set may have no topological
locality. In that case, the anycast address must be maintained as a
separate routing entry throughout the entire Internet ...
... unavailable or very restricted.
One expected use of anycast addresses is to identify the set of
routers belonging to an organization providing Internet service ...
... routers belonging to an organization providing Internet service.
Such addresses could be used as intermediate addresses in an IPv6
Routing header ...
... Internet service.
Such addresses could be used as intermediate addresses in an IPv6
Routing header, to cause a packet to be delivered via a particular
...
... Required Anycast Address ...
... prefix that
identifies a specific link. This anycast address is syntactically
the same as a unicast address for an interface ...
... link. This anycast address is syntactically
the same as a unicast address for an interface on the link with the
...
... Packets sent to the Subnet-Router anycast address will be delivered
to one router on the subnet ...
... The Subnet-Router anycast address is intended to be used for
applications where a node needs to communicate with any one of the
...
... Multicast Addresses ...
... interface may belong to any
number of multicast groups. Multicast addresses have the following
format:
...
...
binary 11111111 at the start of the address identifies the address
as being a multicast address ...
... binary 11111111 at the start of the address identifies the address
as being a multicast address.
...
...
T = 0 indicates a permanently-assigned ("well-known") multicast
address, assigned by the Internet Assigned Numbers Authority
(IANA ...
...
T = 1 indicates a non-permanently-assigned ("transient" or
"dynamically" assigned) multicast address.
The P flag's definition and usage can be found in [RFC3306 ...
... RFC3306].
The "meaning" of a permanently-assigned multicast address is
independent of the scope value. For example, if the "NTP servers
...
... NTP servers
group" is assigned a permanent multicast address with a group ID of
101 (hex), then
...
... Internet.
Non-permanently-assigned multicast addresses are meaningful only
within a given scope. For example, a group identified by the non-
...
... group identified by the non-
permanent, site-local multicast address FF15:0:0:0:0:0:0:101 at one
site bears no relationship to a group using the same address ...
... multicast address FF15:0:0:0:0:0:0:101 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.
Multicast addresses must not be used as source addresses in IPv6
packets or appear in any Routing header ...
...
Multicast addresses must not be used as source addresses in IPv6
packets or appear in any Routing header.
...
... multicast packets beyond of the scope
indicated by the scop field in the destination multicast address.
Nodes ...
...
Nodes must not originate a packet to a multicast address whose scop
field contains the reserved value 0; if such a packet is received, it
must be silently dropped. Nodes ...
... must be silently dropped. Nodes should not originate a packet to a
multicast address whose scop field contains the reserved value F; if
such a packet is sent or received, it must be treated the same as
packets destined to a global (scop E) multicast address ...
... multicast address whose scop field contains the reserved value F; if
such a packet is sent or received, it must be treated the same as
packets destined to a global (scop E) multicast address.
...
... Pre-Defined Multicast Addresses ...
...
The following well-known multicast addresses are pre-defined. The
group IDs defined in this section are defined for explicit scope
...
... equal to 0, is not allowed.
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
...
... FF0F:0:0:0:0:0:0:0
The above multicast addresses are reserved and shall never be
assigned to any multicast group.
...
... node's unicast and anycast addresses. A Solicited-Node multicast
address is formed by taking the low-order 24 bits ...
... unicast and anycast addresses. A Solicited-Node multicast
address is formed by taking the low-order 24 bits of an address
...
... Node multicast
address is formed by taking the low-order 24 bits of an address
(unicast or anycast ...
...
For example, the Solicited-Node multicast address corresponding to
the IPv6 address 4037::01:800:200E:8C6C is FF02::1:FF0E:8C6C. IPv6
addresses ...
... Node multicast address corresponding to
the IPv6 address 4037::01:800:200E:8C6C is FF02::1:FF0E:8C6C. IPv6
addresses that differ only in the high-order bits (e.g., due to
...
... multicast address corresponding to
the IPv6 address 4037::01:800:200E:8C6C is FF02::1:FF0E:8C6C. IPv6
addresses that differ only in the high-order bits (e.g., due to
multiple high-order prefixes ...
... aggregations)
will map to the same Solicited-Node address, thereby reducing the
number of multicast addresses a node ...
... interface)
the associated Solicited-Node multicast addresses for all unicast and
anycast addresses ...
... multicast addresses for all unicast and
anycast addresses that have been configured for the node's interfaces
...
... identifying itself:
o Its required Link-Local address for each interface.
...
...
o Any additional Unicast and Anycast addresses that have been
configured for the node's interfaces ...
...
A router is required to recognize all addresses that a host is
required to recognize, plus the following addresses ...
... addresses that a host is
required to recognize, plus the following addresses as identifying
itself:
...
... o The Subnet-Router Anycast addresses for all interfaces for which
it is configured to act as a router ...
...
o The All-Routers multicast addresses defined in Section 2.7.1.
...
...
The "IPv4-Compatible IPv6 address" is deprecated by this document.
The IANA should continue to list the address ...
... IPv6 address" is deprecated by this document.
The IANA should continue to list the address block containing these
addresses at http://www.iana.org/assignments/ipv6-address ...
... IANA should continue to list the address block containing these
addresses at http://www.iana.org/assignments/ipv6-address-space as
"Reserved by IETF ...
... address block containing these
addresses at http://www.iana.org/assignments/ipv6-address-space as
"Reserved by IETF" and not reassign it for any other purpose. For
...
... The IANA has added the following note and link to this address block.
[5] 0000::/96 was previously defined as the "IPv4 ...
...
[5] 0000::/96 was previously defined as the "IPv4-Compatible IPv6
address" prefix. This definition has been deprecated by RFC
4291draft ...
...
The IANA has updated the references for the IPv6 Address Architecture
in the IANA registries ...
... Fuller, V., Li, T., Yu, J., and K. Varadhan, "Classless Inter-Domain Routing (CIDR): an Address Assignment and Aggregation Strategy", RFC 1519(-> 4632), September 1993. ...
... Hinden, R., Deering, S., and E. Nordmark, "IPv6 Global Unicast Address Format", RFC 3587, August 2003. ...
... Narten, T. and R. Draves, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 3041prop, January 2001. ...
... Savola, P. and B. Haberman, "Embedding the Rendezvous Point (RP) Address in an IPv6 Multicast Address", RFC 3956prop ...
... Huitema, C. and B. Carpenter, "Deprecating Site Local Addresses", RFC 3879prop, September 2004. ...
...
o The restrictions on using IPv6 anycast addresses were removed
because there is now sufficient experience with the use of anycast
addresses ...
... anycast addresses were removed
because there is now sufficient experience with the use of anycast
addresses, the issues are not specific to IPv6, and the GROW
...
...
- Split section titled "Local-use IPv6 Unicast Addresses" into
two sections, "Link-Local IPv6 ...
... Unicast Addresses" and "Site-
Local IPv6 Unicast Addresses".
- Added text to new section describing Site-Local ...
... - Added clarification to Section 2.5 that nodes should make no
assumptions about the structure of an IPv6 address.
- Changed the text in Section 2.5.1 and Appendix A to refer to
...
...
o Removed mention of NSAP addresses in examples.
o Clarified that the "x" in the textual representation can be one to
...
...
o Deprecated the "IPv6 Compatible Address" because it is not being
used in the IPv6 transition mechanisms.
...
... IPv6 transition mechanisms.
o Added the "R" and "P" flags to Section 2.7 on multicast addresses,
and pointers to the documents that define them.
...
... Authors' Addresses ...
... 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.
...