From 4bfd864f10b68b71482b35c818559068ef8d5797 Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Wed, 27 Nov 2024 20:54:24 +0100 Subject: doc: Add RFC documents --- doc/rfc/rfc3513.txt | 1459 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1459 insertions(+) create mode 100644 doc/rfc/rfc3513.txt (limited to 'doc/rfc/rfc3513.txt') diff --git a/doc/rfc/rfc3513.txt b/doc/rfc/rfc3513.txt new file mode 100644 index 0000000..49c0fa4 --- /dev/null +++ b/doc/rfc/rfc3513.txt @@ -0,0 +1,1459 @@ + + + + + + +Network Working Group R. Hinden +Request for Comments: 3513 Nokia +Obsoletes: 2373 S. Deering +Category: Standards Track Cisco Systems + April 2003 + + + Internet Protocol Version 6 (IPv6) Addressing Architecture + +Status of this Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (2003). All Rights Reserved. + +Abstract + + This specification defines the addressing architecture of the IP + Version 6 (IPv6) protocol. The document includes the IPv6 addressing + model, text representations of IPv6 addresses, definition of IPv6 + unicast addresses, anycast addresses, and multicast addresses, and an + IPv6 node's required addresses. + + + + + + + + + + + + + + + + + + + + + + + +Hinden & Deering Standards Track [Page 1] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +Table of Contents + + 1. Introduction.................................................3 + 2. IPv6 Addressing..............................................3 + 2.1 Addressing Model.........................................4 + 2.2 Text Representation of Addresses.........................4 + 2.3 Text Representation of Address Prefixes..................5 + 2.4 Address Type Identification..............................6 + 2.5 Unicast Addresses........................................7 + 2.5.1 Interface Identifiers..............................8 + 2.5.2 The Unspecified Address............................9 + 2.5.3 The Loopback Address...............................9 + 2.5.4 Global Unicast Addresses..........................10 + 2.5.5 IPv6 Addresses with Embedded IPv4 Addresses.......10 + 2.5.6 Local-use IPv6 Unicast Addresses..................11 + 2.6 Anycast Addresses.......................................12 + 2.6.1 Required Anycast Address..........................13 + 2.7 Multicast Addresses.....................................13 + 2.7.1 Pre-Defined Multicast Addresses...................15 + 2.8 A Node's Required Addresses.............................17 + 3. Security Considerations.....................................17 + 4. IANA Considerations.........................................18 + 5. References..................................................19 + 5.1 Normative References....................................19 + 5.2 Informative References..................................19 + APPENDIX A: Creating Modified EUI-64 format Interface IDs......21 + APPENDIX B: Changes from RFC-2373..............................24 + Authors' Addresses.............................................25 + Full Copyright Statement.......................................26 + + + + + + + + + + + + + + + + + + + + + + +Hinden & Deering Standards Track [Page 2] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +1. Introduction + + This specification defines the addressing architecture of the IP + Version 6 (IPv6) protocol. It includes the basic formats for the + various types of IPv6 addresses (unicast, anycast, and multicast). + + The authors would like to acknowledge the contributions of Paul + Francis, Scott Bradner, Jim Bound, Brian Carpenter, Matt Crawford, + Deborah Estrin, Roger Fajman, Bob Fink, Peter Ford, Bob Gilligan, + Dimitry Haskin, Tom Harsch, Christian Huitema, Tony Li, Greg + Minshall, Thomas Narten, Erik Nordmark, Yakov Rekhter, Bill Simpson, + Sue Thomson, Markku Savela, and Larry Masinter. + +2. IPv6 Addressing + + IPv6 addresses are 128-bit identifiers for interfaces and sets of + interfaces (where "interface" is as defined in section 2 of [IPV6]). + There are three types of addresses: + + Unicast: An identifier for a single interface. A packet sent to a + unicast address is delivered to the interface identified + by that address. + + Anycast: An identifier for a set of interfaces (typically belonging + to different nodes). A packet sent to an anycast address + is delivered to one of the interfaces identified by that + address (the "nearest" one, according to the routing + protocols' measure of distance). + + Multicast: An identifier for a set of interfaces (typically belonging + to different nodes). A packet sent to a multicast address + is delivered to all interfaces identified by that 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 "subnet". When this name is used with the term "ID" for + identifier after the name (e.g., "subnet ID"), it refers to the + contents of the named field. When it is used with the term "prefix" + (e.g., "subnet prefix") it refers to all of the address from the left + 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, or + end with, zero-valued fields. + + + + + +Hinden & Deering Standards Track [Page 3] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +2.1 Addressing Model + + IPv6 addresses of all types are assigned to interfaces, not nodes. + An IPv6 unicast address refers to a single interface. 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. + + All 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 of any type + (unicast, anycast, and multicast) or scope. Unicast addresses with + scope greater than link-scope are not needed for interfaces that are + not used as the origin or destination of any IPv6 packets to or from + non-neighbors. This is sometimes convenient for point-to-point + interfaces. There is one exception to this addressing model: + + A unicast address or a set of unicast addresses 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. + + Currently IPv6 continues the IPv4 model that a subnet prefix is + associated with one link. Multiple subnet prefixes 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 + + 1080:0:0:0:8:800:200C: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 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 containing zero + bits easier a special syntax is available to compress the zeros. + + + +Hinden & Deering Standards Track [Page 4] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + The use of "::" indicates one or more 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. + + For example, the following addresses: + + 1080:0:0:0:8:800:200C: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 + 0:0:0:0:0:0:0:0 the unspecified addresses + + may be represented as: + + 1080::8:800:200C:417A a unicast address + FF01::101 a multicast address + ::1 the loopback address + :: the unspecified addresses + + 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: + + 0:0:0:0:0:0:13.1.68.3 + + 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 Text Representation of Address Prefixes + + The text representation of IPv6 address prefixes is similar to the + way IPv4 addresses prefixes are written in CIDR notation [CIDR]. An + IPv6 address prefix is 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. + + + + +Hinden & Deering Standards Track [Page 5] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + prefix-length is a decimal value specifying how many of the + leftmost contiguous bits of the address comprise + the prefix. + + For example, the following are legal representations of the 60-bit + prefix 12AB00000000CD3 (hexadecimal): + + 12AB:0000:0000:CD30:0000:0000:0000:0000/60 + 12AB::CD30:0:0:0:0/60 + 12AB:0:0:CD30::/60 + + The following are NOT legal representations of the above prefix: + + 12AB:0:0:CD3/60 may drop leading zeros, but not trailing zeros, + within any 16-bit chunk of the address + + 12AB::CD30/60 address to left of "/" expands to + 12AB:0000:0000:0000:0000:000:0000:CD30 + + 12AB::CD3/60 address to left of "/" expands to + 12AB:0000:0000:0000:0000:000:0000:0CD3 + + When writing both a node address and a prefix of that node address + (e.g., the node's subnet prefix), the two can combined as follows: + + the node address 12AB:0:0:CD30:123:4567:89AB:CDEF + and its subnet number 12AB:0:0:CD30::/60 + + can be abbreviated as 12AB:0:0:CD30:123:4567:89AB:CDEF/60 + +2.4 Address Type Identification + + The type of an IPv6 address is identified by the high-order bits of + the address, as follows: + + Address type Binary prefix IPv6 notation Section + ------------ ------------- ------------- ------- + Unspecified 00...0 (128 bits) ::/128 2.5.2 + Loopback 00...1 (128 bits) ::1/128 2.5.3 + Multicast 11111111 FF00::/8 2.7 + Link-local unicast 1111111010 FE80::/10 2.5.6 + Site-local unicast 1111111011 FEC0::/10 2.5.6 + Global unicast (everything else) + + Anycast addresses are taken from the unicast address spaces (of any + scope) and are not syntactically distinguishable from unicast + addresses. + + + + +Hinden & Deering Standards Track [Page 6] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + The general format of global unicast addresses is described in + section 2.5.4. Some special-purpose subtypes of global unicast + addresses which contain embedded IPv4 addresses (for the purposes of + IPv4-IPv6 interoperation) are described in section 2.5.5. + + Future specifications may redefine one or more sub-ranges of the + 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 as global unicast addresses. + +2.5 Unicast Addresses + + IPv6 unicast addresses are aggregable with prefixes of arbitrary + bit-length similar to IPv4 addresses under Classless Interdomain + Routing. + + There are several types of unicast addresses in IPv6, in particular + global unicast, site-local unicast, and link-local unicast. There + are also some special-purpose subtypes of global unicast, such as + IPv6 addresses with embedded IPv4 addresses or encoded NSAP + 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 + (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: + + | n bits | 128-n bits | + +------------------------------------------------+----------------+ + | subnet prefix | interface ID | + +------------------------------------------------+----------------+ + + 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 + + + +Hinden & Deering Standards Track [Page 7] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + from router to router, depending on what positions the router holds + in the routing hierarchy. + +2.5.1 Interface Identifiers + + Interface identifiers in IPv6 unicast addresses are used to identify + interfaces on a link. They are required to be unique within a subnet + prefix. It is recommended that the same interface identifier not be + assigned to different nodes on a link. They may also be unique over + a broader scope. In some cases an interface's identifier will be + derived directly from that interface's link-layer address. The same + interface identifier may be used on multiple interfaces on a single + node, as long as they are attached to different subnets. + + Note that the uniqueness of interface identifiers is independent of + the uniqueness of IPv6 addresses. For example, a global unicast + address may be created with a non-global scope interface identifier + and a site-local address may be created with a global scope interface + identifier. + + For all unicast addresses, except those that start with binary value + 000, Interface IDs are required to be 64 bits long and to be + constructed in Modified EUI-64 format. + + Modified EUI-64 format based Interface identifiers may have global + scope when derived from a global token (e.g., IEEE 802 48-bit MAC or + IEEE EUI-64 identifiers [EUI64]) or may have local scope where a + global token is not available (e.g., serial links, tunnel end-points, + etc.) or where global tokens are undesirable (e.g., temporary tokens + for privacy [PRIV]). + + Modified EUI-64 format interface identifiers are formed by inverting + the "u" bit (universal/local bit in IEEE EUI-64 terminology) when + forming the interface identifier from IEEE EUI-64 identifiers. In + the resulting Modified EUI-64 format the "u" bit is set to one (1) to + indicate global scope, and it is set to zero (0) to indicate local + scope. The first three octets in binary of an IEEE EUI-64 identifier + are as follows: + + 0 0 0 1 1 2 + |0 7 8 5 6 3| + +----+----+----+----+----+----+ + |cccc|ccug|cccc|cccc|cccc|cccc| + +----+----+----+----+----+----+ + + written in Internet standard bit-order , where "u" is the + universal/local bit, "g" is the individual/group bit, and "c" are the + bits of the company_id. Appendix A: "Creating Modified EUI-64 format + + + +Hinden & Deering Standards Track [Page 8] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + Interface Identifiers" provides examples on the creation of Modified + EUI-64 format based interface identifiers. + + The motivation for inverting the "u" bit when forming an interface + identifier is to make it easy for system administrators to hand + configure non-global identifiers when hardware tokens are not + available. This is expected to be case for serial links, tunnel end- + points, etc. The alternative would have been for these to be of the + form 0200:0:0:1, 0200:0:0:2, etc., instead of the much simpler 1, 2, + etc. + + The use of the universal/local bit in the Modified EUI-64 format + identifier is to allow development of future technology that can take + advantage of interface identifiers with global scope. + + The details of forming interface identifiers are defined in the + appropriate "IPv6 over " specification such as "IPv6 over + Ethernet" [ETHER], "IPv6 over FDDI" [FDDI], etc. + +2.5.2 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. One example of its use is in the Source Address field of + any IPv6 packets sent by an initializing host before it has learned + its own address. + + 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. + +2.5.3 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 an IPv6 packet to itself. It may + never be assigned to any physical interface. It is treated as + having 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 that goes nowhere. + + 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 with + a destination address of loopback must never be sent outside of a + single node and must never be forwarded by an IPv6 router. A packet + received on an interface with destination address of loopback must be + dropped. + + + + +Hinden & Deering Standards Track [Page 9] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +2.5.4 Global Unicast Addresses + + The general format for IPv6 global unicast addresses is as follows: + + | n bits | m bits | 128-n-m bits | + +------------------------+-----------+----------------------------+ + | global routing prefix | subnet ID | interface ID | + +------------------------+-----------+----------------------------+ + + where the global routing prefix is a (typically hierarchically- + structured) value assigned to a site (a cluster of subnets/links), + the subnet ID is an identifier of a link within the site, and the + interface ID is as defined in section 2.5.1. + + All global unicast addresses other than those that start with binary + 000 have a 64-bit 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 on the size or structure of the + interface ID field. + + Examples of global unicast addresses that start with binary 000 are + the IPv6 address with embedded IPv4 addresses described in section + 2.5.5 and the IPv6 address containing encoded NSAP addresses + specified in [NSAP]. An example of global addresses starting with a + binary value other than 000 (and therefore having a 64-bit interface + ID field) can be found in [AGGR]. + +2.5.5 IPv6 Addresses with Embedded IPv4 Addresses + + The IPv6 transition mechanisms [TRAN] include a technique for hosts + and routers to dynamically tunnel IPv6 packets over IPv4 routing + infrastructure. IPv6 nodes that use this technique are assigned + special IPv6 unicast addresses that carry a global IPv4 address in + the 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 | + +--------------------------------------+----+---------------------+ + + Note: The IPv4 address used in the "IPv4-compatible IPv6 address" + must be a globally-unique IPv4 unicast address. + + A second type of IPv6 address which holds an embedded IPv4 address is + also defined. This address type is used to represent the addresses + of IPv4 nodes as IPv6 addresses. This type of address is termed an + "IPv4-mapped IPv6 address" and has the format: + + + +Hinden & Deering Standards Track [Page 10] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + | 80 bits | 16 | 32 bits | + +--------------------------------------+--------------------------+ + |0000..............................0000|FFFF| IPv4 address | + +--------------------------------------+----+---------------------+ + +2.5.6 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 | 54 bits | 64 bits | + +----------+-------------------------+----------------------------+ + |1111111010| 0 | interface ID | + +----------+-------------------------+----------------------------+ + + Link-Local addresses are designed to be used for addressing on a + single link for purposes such as automatic address configuration, + neighbor discovery, or when no routers are present. + + Routers must not forward any packets with link-local source or + destination addresses to other links. + + Site-Local addresses have the following format: + + | 10 | + | bits | 54 bits | 64 bits | + +----------+-------------------------+----------------------------+ + |1111111011| subnet ID | interface ID | + +----------+-------------------------+----------------------------+ + + Site-local addresses are designed to be used for addressing inside of + a site without the need for a global prefix. Although a subnet ID + may be up to 54-bits long, it is expected that globally-connected + sites will use the same subnet IDs for site-local and global + prefixes. + + Routers must not forward any packets with site-local source or + destination addresses outside of the site. + + + + + + + + + + +Hinden & Deering Standards Track [Page 11] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +2.6 Anycast Addresses + + An IPv6 anycast address is an address that is assigned to more than + one 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, according to the routing + protocols' measure of distance. + + 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. When a + unicast address is assigned to more than one interface, thus turning + 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. + + For any assigned 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 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 + route"); outside the region identified by P, the anycast address may + be aggregated into the routing entry for prefix P. + + Note that in the worst case, the prefix P of an anycast set may be + 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, which presents + a severe scaling limit on how many such "global" anycast sets may be + supported. Therefore, it is expected that support for global anycast + sets may be unavailable or very restricted. + + One expected use of anycast addresses is to identify the set of + routers belonging to an organization providing 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 + service provider or sequence of service providers. + + Some other possible uses are to identify the set of routers attached + to a particular subnet, or the set of routers providing entry into a + 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 are specified, the following + restrictions are imposed on IPv6 anycast addresses: + + + + +Hinden & Deering Standards Track [Page 12] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + o An anycast address must not be used as the source address of an + IPv6 packet. + + o An anycast address must not be assigned to an IPv6 host, that is, + it may be assigned to an IPv6 router only. + +2.6.1 Required Anycast Address + + The Subnet-Router anycast address is predefined. Its format is as + follows: + + | n bits | 128-n bits | + +------------------------------------------------+----------------+ + | subnet prefix | 00000000000000 | + +------------------------------------------------+----------------+ + + The "subnet prefix" in an anycast address is the prefix which + identifies a specific link. This anycast address is syntactically + the same as a unicast address for an interface on the link with the + interface identifier set to zero. + + Packets sent to the Subnet-Router anycast address will be delivered + to one router on the subnet. All routers are required to support the + Subnet-Router anycast addresses for the subnets to which they have + interfaces. + + The subnet-router anycast address is intended to be used for + applications where a node needs to communicate with any one of the + set of routers. + +2.7 Multicast Addresses + + An IPv6 multicast address is an identifier for a group of interfaces + (typically on different nodes). An interface may belong to any + number of multicast groups. Multicast addresses have the following + format: + + | 8 | 4 | 4 | 112 bits | + +------ -+----+----+---------------------------------------------+ + |11111111|flgs|scop| group ID | + +--------+----+----+---------------------------------------------+ + + binary 11111111 at the start of the address identifies the + address as being a multicast address. + + +-+-+-+-+ + flgs is a set of 4 flags: |0|0|0|T| + +-+-+-+-+ + + + +Hinden & Deering Standards Track [Page 13] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + 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 Internet Assigned Number + Authority (IANA). + + T = 1 indicates a non-permanently-assigned ("transient") + multicast address. + + scop is a 4-bit multicast scope value used to limit the scope + of the multicast group. The values are: + + 0 reserved + 1 interface-local scope + 2 link-local scope + 3 reserved + 4 admin-local scope + 5 site-local scope + 6 (unassigned) + 7 (unassigned) + 8 organization-local scope + 9 (unassigned) + A (unassigned) + B (unassigned) + C (unassigned) + D (unassigned) + E global scope + F reserved + + interface-local scope spans only a single interface on a + node, and is useful only for loopback transmission of + multicast. + + link-local and site-local multicast scopes span the same + topological regions as the corresponding unicast scopes. + + admin-local scope is the smallest scope that must be + administratively configured, i.e., not automatically derived + from physical connectivity or other, non- multicast-related + configuration. + + organization-local scope is intended to span multiple sites + belonging to a single organization. + + scopes labeled "(unassigned)" are available for + administrators to define additional multicast regions. + + + + +Hinden & Deering Standards Track [Page 14] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + 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 + 101 (hex), then: + + FF01:0:0:0:0:0:0:101 means all NTP servers on the same interface + (i.e., the same node) as the sender. + + FF02:0:0:0:0:0:0:101 means all NTP servers on the same link as the + sender. + + FF05:0:0:0:0:0:0:101 means all NTP servers in the same site as the + sender. + + FF0E:0:0:0:0:0:0:101 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 FF15:0:0:0:0:0:0:101 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 + with different scope, nor to a permanent group with the same group + ID. + + Multicast addresses must not be used as source addresses in IPv6 + packets or appear in any Routing header. + + Routers must not forward any multicast packets beyond of the scope + indicated by the scop field in the destination multicast address. + + 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 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. + +2.7.1 Pre-Defined Multicast Addresses + + The following well-known multicast addresses are pre-defined. The + group ID's defined in this section are defined for explicit scope + values. + + Use of these group IDs for any other scope values, with the T flag + equal to 0, is not allowed. + + + +Hinden & Deering Standards Track [Page 15] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + 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 (interface-local) or 2 (link-local). + + All Routers Addresses: FF01:0:0:0:0:0:0:2 + FF02:0:0:0:0:0:0:2 + FF05:0:0:0:0:0:0:2 + + The above multicast addresses identify the group of all IPv6 routers, + within scope 1 (interface-local), 2 (link-local), or 5 (site-local). + + Solicited-Node Address: FF02:0:0:0:0:1:FFXX:XXXX + + Solicited-node multicast address are computed as a function of a + node's unicast and anycast addresses. A solicited-node multicast + address is formed by taking the low-order 24 bits of an address + (unicast or anycast) and appending those bits to the prefix + FF02:0:0:0:0:1:FF00::/104 resulting in a multicast address in the + range + + FF02:0:0:0:0:1:FF00:0000 + + to + + FF02:0:0:0:0:1:FFFF:FFFF + + + + +Hinden & Deering Standards Track [Page 16] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + For example, the solicited 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 + multiple high-order prefixes associated with different aggregations, + will map to the same solicited-node address thereby, reducing the + number of multicast addresses a node must join. + + A node is required to compute and join (on the appropriate interface) + the associated Solicited-Node multicast addresses for every unicast + and anycast address it is assigned. + +2.8 A Node's Required Addresses + + A host is required to recognize the following addresses as + 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 (manually or + automatically). + o The loopback address. + o The All-Nodes Multicast Addresses defined in section 2.7.1. + o The Solicited-Node Multicast Address for each of its unicast + and anycast addresses. + o Multicast Addresses of all other groups to which the node + belongs. + + A router is required to recognize all 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 All other Anycast Addresses with which the router has been + configured. + o The All-Routers Multicast Addresses defined in section 2.7.1. + +3. Security Considerations + + IPv6 addressing documents do not have any direct impact on Internet + infrastructure security. Authentication of IPv6 packets is defined + in [AUTH]. + + + + + + + + + +Hinden & Deering Standards Track [Page 17] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +4. IANA Considerations + + The table and notes at http://www.isi.edu/in- + notes/iana/assignments/ipv6-address-space.txt should be replaced with + the following: + + INTERNET PROTOCOL VERSION 6 ADDRESS SPACE + + The initial assignment of IPv6 address space is as follows: + + Allocation Prefix Fraction of + (binary) Address Space + ----------------------------------- -------- ------------- + Unassigned (see Note 1 below) 0000 0000 1/256 + Unassigned 0000 0001 1/256 + Reserved for NSAP Allocation 0000 001 1/128 [RFC1888] + Unassigned 0000 01 1/64 + Unassigned 0000 1 1/32 + Unassigned 0001 1/16 + Global Unicast 001 1/8 [RFC2374] + Unassigned 010 1/8 + Unassigned 011 1/8 + Unassigned 100 1/8 + Unassigned 101 1/8 + Unassigned 110 1/8 + Unassigned 1110 1/16 + Unassigned 1111 0 1/32 + Unassigned 1111 10 1/64 + Unassigned 1111 110 1/128 + Unassigned 1111 1110 0 1/512 + Link-Local Unicast Addresses 1111 1110 10 1/1024 + Site-Local Unicast Addresses 1111 1110 11 1/1024 + Multicast Addresses 1111 1111 1/256 + + Notes: + + 1. The "unspecified address", the "loopback address", and the IPv6 + Addresses with Embedded IPv4 Addresses are assigned out of the + 0000 0000 binary prefix space. + + 2. For now, IANA should limit its allocation of IPv6 unicast address + space to the range of addresses that start with binary value 001. + The rest of the global unicast address space (approximately 85% of + the IPv6 address space) is reserved for future definition and use, + and is not to be assigned by IANA at this time. + + + + + + +Hinden & Deering Standards Track [Page 18] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +5. References + +5.1 Normative References + + [IPV6] Deering, S. and R. Hinden, "Internet Protocol, Version 6 + (IPv6) Specification", RFC 2460, December 1998. + + [RFC2026] Bradner, S., "The Internet Standards Process -- Revision + 3", BCP 9 , RFC 2026, October 1996. + +5.2 Informative References + + [ANYCST] Partridge, C., Mendez, T. and W. Milliken, "Host Anycasting + Service", RFC 1546, November 1993. + + [AUTH] Kent, S. and R. Atkinson, "IP Authentication Header", RFC + 2402, November 1998. + + [AGGR] Hinden, R., O'Dell, M. and S. Deering, "An Aggregatable + Global Unicast Address Format", RFC 2374, July 1998. + + [CIDR] Fuller, V., Li, T., Yu, J. and K. Varadhan, "Classless + Inter-Domain Routing (CIDR): An Address Assignment and + Aggregation Strategy", RFC 1519, September 1993. + + [ETHER] Crawford, M., "Transmission of IPv6 Packets over Ethernet + Networks", RFC 2464, December 1998. + + [EUI64] IEEE, "Guidelines for 64-bit Global Identifier (EUI-64) + Registration Authority", + http://standards.ieee.org/regauth/oui/tutorials/EUI64.html, + March 1997. + + [FDDI] Crawford, M., "Transmission of IPv6 Packets over FDDI + Networks", RFC 2467, December 1998. + + [MASGN] Hinden, R. and S. Deering, "IPv6 Multicast Address + Assignments", RFC 2375, July 1998. + + [NSAP] Bound, J., Carpenter, B., Harrington, D., Houldsworth, J. + and A. Lloyd, "OSI NSAPs and IPv6", RFC 1888, August 1996. + + [PRIV] Narten, T. and R. Draves, "Privacy Extensions for Stateless + Address Autoconfiguration in IPv6", RFC 3041, January 2001. + + [TOKEN] Crawford, M., Narten, T. and S. Thomas, "Transmission of + IPv6 Packets over Token Ring Networks", RFC 2470, December + 1998. + + + +Hinden & Deering Standards Track [Page 19] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + [TRAN] Gilligan, R. and E. Nordmark, "Transition Mechanisms for + IPv6 Hosts and Routers", RFC 2893, August 2000. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Hinden & Deering Standards Track [Page 20] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +APPENDIX A: Creating Modified EUI-64 format Interface Identifiers + + Depending on the characteristics of a specific link or node there are + a number of approaches for creating Modified EUI-64 format interface + identifiers. This appendix describes some of these approaches. + +Links or Nodes with IEEE EUI-64 Identifiers + + The only change needed to transform an IEEE EUI-64 identifier to an + interface identifier is to invert the "u" (universal/local) bit. For + example, a globally unique IEEE EUI-64 identifier of the form: + + |0 1|1 3|3 4|4 6| + |0 5|6 1|2 7|8 3| + +----------------+----------------+----------------+----------------+ + |cccccc0gcccccccc|ccccccccmmmmmmmm|mmmmmmmmmmmmmmmm|mmmmmmmmmmmmmmmm| + +----------------+----------------+----------------+----------------+ + + where "c" are the bits of the assigned company_id, "0" is the value + of the universal/local bit to indicate global scope, "g" is + individual/group bit, and "m" are the bits of the manufacturer- + selected extension identifier. The IPv6 interface identifier would + be of the form: + + |0 1|1 3|3 4|4 6| + |0 5|6 1|2 7|8 3| + +----------------+----------------+----------------+----------------+ + |cccccc1gcccccccc|ccccccccmmmmmmmm|mmmmmmmmmmmmmmmm|mmmmmmmmmmmmmmmm| + +----------------+----------------+----------------+----------------+ + + The only change is inverting the value of the universal/local bit. + +Links or Nodes with IEEE 802 48 bit MAC's + + [EUI64] defines a method to create a IEEE EUI-64 identifier from an + IEEE 48bit MAC identifier. This is to insert two octets, with + hexadecimal values of 0xFF and 0xFE, in the middle of the 48 bit MAC + (between the company_id and vendor supplied id). For example, the 48 + bit IEEE MAC with global scope: + + + + + + + + + + + + +Hinden & Deering Standards Track [Page 21] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + |0 1|1 3|3 4| + |0 5|6 1|2 7| + +----------------+----------------+----------------+ + |cccccc0gcccccccc|ccccccccmmmmmmmm|mmmmmmmmmmmmmmmm| + +----------------+----------------+----------------+ + + where "c" are the bits of the assigned company_id, "0" is the value + of the universal/local bit to indicate global scope, "g" is + individual/group bit, and "m" are the bits of the manufacturer- + selected extension identifier. The interface identifier would be of + the form: + + |0 1|1 3|3 4|4 6| + |0 5|6 1|2 7|8 3| + +----------------+----------------+----------------+----------------+ + |cccccc1gcccccccc|cccccccc11111111|11111110mmmmmmmm|mmmmmmmmmmmmmmmm| + +----------------+----------------+----------------+----------------+ + + When IEEE 802 48bit MAC addresses are available (on an interface or a + node), an implementation may use them to create interface identifiers + due to their availability and uniqueness properties. + +Links with Other Kinds of Identifiers + + There are a number of types of links that have link-layer interface + identifiers other than IEEE EIU-64 or IEEE 802 48-bit MACs. Examples + include LocalTalk and Arcnet. The method to create an Modified EUI- + 64 format identifier is to take the link identifier (e.g., the + LocalTalk 8 bit node identifier) and zero fill it to the left. For + example, a LocalTalk 8 bit node identifier of hexadecimal value 0x4F + results in the following interface identifier: + + |0 1|1 3|3 4|4 6| + |0 5|6 1|2 7|8 3| + +----------------+----------------+----------------+----------------+ + |0000000000000000|0000000000000000|0000000000000000|0000000001001111| + +----------------+----------------+----------------+----------------+ + + Note that this results in the universal/local bit set to "0" to + indicate local scope. + +Links without Identifiers + + There are a number of links that do not have any type of built-in + identifier. The most common of these are serial links and configured + tunnels. Interface identifiers must be chosen that are unique within + a subnet-prefix. + + + + +Hinden & Deering Standards Track [Page 22] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + When no built-in identifier is available on a link the preferred + approach is to use a global interface identifier from another + interface or one which is assigned to the node itself. When using + this approach no other interface connecting the same node to the same + subnet-prefix may use the same identifier. + + If there is no global interface identifier available for use on the + link the implementation needs to create a local-scope interface + identifier. The only requirement is that it be unique within a + subnet prefix. There are many possible approaches to select a + subnet-prefix-unique interface identifier. These include: + + Manual Configuration + Node Serial Number + Other node-specific token + + The subnet-prefix-unique interface identifier should be generated in + a manner that it does not change after a reboot of a node or if + interfaces are added or deleted from the node. + + The selection of the appropriate algorithm is link and implementation + dependent. The details on forming interface identifiers are defined + in the appropriate "IPv6 over " specification. It is strongly + recommended that a collision detection algorithm be implemented as + part of any automatic algorithm. + + + + + + + + + + + + + + + + + + + + + + + + + + +Hinden & Deering Standards Track [Page 23] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +APPENDIX B: Changes from RFC-2373 + + The following changes were made from RFC-2373 "IP Version 6 + Addressing Architecture": + + - Clarified text in section 2.2 to allow "::" to represent one or + more groups of 16 bits of zeros. + - Changed uniqueness requirement of Interface Identifiers from + unique on a link to unique within a subnet prefix. Also added a + recommendation that the same interface identifier not be assigned + to different machines on a link. + - Change site-local format to make the subnet ID field 54-bit long + and remove the 38-bit zero's field. + - Added description of multicast scop values and rules to handle the + reserved scop value 0. + - Revised sections 2.4 and 2.5.6 to simplify and clarify how + different address types are identified. This was done to insure + that implementations do not build in any knowledge about global + unicast format prefixes. Changes include: + o Removed Format Prefix (FP) terminology + o Revised list of address types to only include exceptions to + global unicast and a singe entry that identifies everything + else as Global Unicast. + o Removed list of defined prefix exceptions from section 2.5.6 + as it is now the main part of section 2.4. + - Clarified text relating to EUI-64 identifiers to distinguish + between IPv6's "Modified EUI-64 format" identifiers and IEEE EUI- + 64 identifiers. + - Combined the sections on the Global Unicast Addresses and NSAP + Addresses into a single section on Global Unicast Addresses, + generalized the Global Unicast format, and cited [AGGR] and [NSAP] + as examples. + - Reordered sections 2.5.4 and 2.5.5. + - Removed section 2.7.2 Assignment of New IPv6 Multicast Addresses + because this is being redefined elsewhere. + - Added an IANA considerations section that updates the IANA IPv6 + address allocations and documents the NSAP and AGGR allocations. + - Added clarification that the "IPv4-compatible IPv6 address" must + use global IPv4 unicast addresses. + - Divided references in to normative and non-normative sections. + - Added reference to [PRIV] in section 2.5.1 + - Added clarification that routers must not forward multicast + packets outside of the scope indicated in the multicast address. + - Added clarification that routers must not forward packets with + source address of the unspecified address. + - Added clarification that routers must drop packets received on an + interface with destination address of loopback. + - Clarified the definition of IPv4-mapped addresses. + + + +Hinden & Deering Standards Track [Page 24] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + + - Removed the ABNF Description of Text Representations Appendix. + - Removed the address block reserved for IPX addresses. + - Multicast scope changes: + o Changed name of scope value 1 from "node-local" to + "interface-local" + o Defined scope value 4 as "admin-local" + - Corrected reference to RFC1933 and updated references. + - Many small changes to clarify and make the text more consistent. + +Authors' Addresses + + Robert M. Hinden + Nokia + 313 Fairchild Drive + Mountain View, CA 94043 + USA + + Phone: +1 650 625-2004 + EMail: hinden@iprg.nokia.com + + + Stephen E. Deering + Cisco Systems, Inc. + 170 West Tasman Drive + San Jose, CA 95134-1706 + USA + + Phone: +1 408 527-8213 + EMail: deering@cisco.com + + + + + + + + + + + + + + + + + + + + + + +Hinden & Deering Standards Track [Page 25] + +RFC 3513 IPv6 Addressing Architecture April 2003 + + +Full Copyright Statement + + Copyright (C) The Internet Society (2003). All Rights Reserved. + + This document and translations of it may be copied and furnished to + others, and derivative works that comment on or otherwise explain it + or assist in its implementation may be prepared, copied, published + and distributed, in whole or in part, without restriction of any + kind, provided that the above copyright notice and this paragraph are + included on all such copies and derivative works. However, this + document itself may not be modified in any way, such as by removing + the copyright notice or references to the Internet Society or other + Internet organizations, except as needed for the purpose of + developing Internet standards in which case the procedures for + copyrights defined in the Internet Standards process must be + followed, or as required to translate it into languages other than + English. + + The limited permissions granted above are perpetual and will not be + revoked by the Internet Society or its successors or assigns. + + This document and the information contained herein is provided on an + "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING + TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING + BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION + HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF + MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + +Acknowledgement + + Funding for the RFC Editor function is currently provided by the + Internet Society. + + + + + + + + + + + + + + + + + + + +Hinden & Deering Standards Track [Page 26] + -- cgit v1.2.3