Network Working Group F. Templin Internet-Draft Nokia Expires: April 14, 2004 T. Gleeson Cisco Systems K.K. M. Talwar D. Thaler Microsoft Corporation October 15, 2003 Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) draft-ietf-ngtrans-isatap-16.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 14, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document specifies an Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) that connects IPv6 hosts and routers within IPv4 sites. ISATAP treats the site's IPv4 unicast infrastructure as a Non-Broadcast, Multiple Access (NBMA) link layer for IPv6 with no requirement for IPv4 multicast. ISATAP enables automatic IPv6-in-IPv4 tunneling whether globally assigned or private IPv4 addresses are used. Templin, et al. Expires April 14, 2004 [Page 1] Internet-Draft ISATAP October 2003 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Basic IPv6 Operation . . . . . . . . . . . . . . . . . . . . . 4 5. Automatic Tunneling . . . . . . . . . . . . . . . . . . . . . 6 6. Neighbor Discovery . . . . . . . . . . . . . . . . . . . . . . 8 7. Address Autoconfiguration . . . . . . . . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 9. Security considerations . . . . . . . . . . . . . . . . . . . 12 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 Normative References . . . . . . . . . . . . . . . . . . . . . 13 Informative References . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 15 A. Major Changes . . . . . . . . . . . . . . . . . . . . . . . . 15 B. Interface Identifier Construction . . . . . . . . . . . . . . 16 Intellectual Property and Copyright Statements . . . . . . . . 18 Templin, et al. Expires April 14, 2004 [Page 2] Internet-Draft ISATAP October 2003 1. Introduction This document specifies a simple mechanism called the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) that enables incremental deployment of IPv6 [RFC2460] within IPv4 [RFC0791] sites. ISATAP allows dual-stack nodes that do not share a link with an IPv6 router to automatically tunnel packets to the IPv6 next-hop address through IPv4, i.e., the site's IPv4 infrastructure is treated as a link layer for IPv6. The main objectives of this document are to: 1) specify operational details for automatic tunneling of IPv6 over IPv4 using ISATAP, 2) specify the format of IPv6 interface identifiers using an embedded IPv4 address, 3) specify the operation of Neighbor Discovery and Address Autoconfiguration, and 4) discuss security considerations. The specification in this document is very similar to [RFC2529], with the primary distinction that ISATAP does not require IPv4 multicast support within the site. 2. Requirements The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this document, are to be interpreted as described in [RFC2119]. This document also makes use of internal conceptual variables to describe protocol behavior and external variables that an implementation must allow system administrators to change. The specific variable names, how their values change, and how their settings influence protocol behavior are provided to demonstrate protocol behavior. An implementation is not required to have them in the exact form described here, so long as its external behavior is consistent with that described in this document. 3. Terminology The terminology of [RFC2460][RFC2461][RFC2462] applies to this document. The following additional terms are defined: site: same as defined in [RFC3582], which is intended to be equivalent to "enterprise" as defined in [RFC1918]. ISATAP interface: an interface used for automatic IPv6-in-IPv4 tunneling and configured over one or more IPv4 addresses assigned to one or more of the node's IPv4 interfaces that belong to the same site. Templin, et al. Expires April 14, 2004 [Page 3] Internet-Draft ISATAP October 2003 advertising ISATAP interface: same meaning as advertising interface in ([RFC2461], section 6.2.2). ISATAP address: an address with an on-link prefix assigned on an ISATAP interface and with an interface identifier constructed as specified in Section 4.1. 4. Basic IPv6 Operation ISATAP interfaces automatically tunnel IPv6 packets in IPv4 using the site's IPv4 infrastructure as a link layer, i.e., IPv6 treats the site's IPv4 infrastructure as a Non-Broadcast, Multiple Access (NBMA) link layer with properties similar to [RFC2491]. The following sections specify details for basic IPv6 operation on ISATAP interfaces: 4.1 Interface Identifiers and Unicast Addresses Interface identifiers for ISATAP are constructed in Modified EUI-64 format as specified in ([ADDR-ARCH], section 2.5.1). They are formed by appending a 32-bit IPv4 address to the 32-bit leading token '0000:5EFE', then setting the universal/local ("u") bit as follows: When the IPv4 address is globally unique (i.e., provider-assigned), the "u" bit is set to 1 and the leading token becomes '0200:5EFE'. When the IPv4 address is from a private allocation [RFC1918], the "u" bit is set to 0 and the leading token remains as '0000:5EFE'. Global and link-local IPv6 unicast addresses ([ADDR-ARCH], sections 2.5.4, 2.5.6) for ISATAP are constructed as follows: | 64 bits | 32 bits | 32 bits | +------------------------------+---------------+----------------+ | global/link-local prefix | 000[0/2]:5EFE | IPv4 Address | +------------------------------+---------------+----------------+ (Appendix B provides additional non-normative details.) 4.2 ISATAP Interface Management The IP Tunnel MIB [MIB] is used, with the following additions for ISATAP interfaces: o For each IPv4 address an ISATAP interface is configured over, a tuple consisting of the IPv4 address and ifIndex for the Templin, et al. Expires April 14, 2004 [Page 4] Internet-Draft ISATAP October 2003 corresponding IPv4 interface ([RFC2863], section 3.1.5) is added to ifRcvAddressTable ([MIB], section 3.1.2). o tunnelIfRemoteInetAddress in the tunnelIfEntry object ([MIB], section 4) is set to 0.0.0.0 for ISATAP interfaces. When an IPv4 address over which an ISATAP interface is configured is removed from its IPv4 interface, the corresponding (IPv4 addres, ifIndex)-tuple MUST be removed from the ISATAP interface ifRcvAddressTable. If the IPv4 address is also used as tunnelIfLocalInetAddress ([MIB], section 5) in the ISATAP interface tunnelIfEntry, the interface MUST either set tunnelIfLocalInetAddress to a different IPv4 address or be disabled. When a new IPv4 address is added to an IPv4 interface an ISATAP interface is configured over, a new (IPv4 address, ifIndex)-tuple MAY be added to ifRcvAddressTable and tunnelIfLocalInetAddress MAY be set to the new address. 4.3 Multicast and Anycast ISATAP interfaces recognize an IPv6 node's required addresses ([ADDR-ARCH], section 2.8). The following multicast mappings are defined for packets sent on ISATAP interfaces: o When the IPv6 destination address is the 'All-Routers' ([ADDR-ARCH], section 2.7.1) or 'All_DHCP_Relay_Agents_and_Servers' ([RFC3315], section 1.2) multicast address, it is mapped to V4ADDR(i) for one or more PRL(i)'s (see: Section 6.1). The manner of selecting PRL(i)'s is up to the implementation. Other multicast mappings, and mechanisms for general-purpose multicast/anycast emulation on ISATAP interfaces are beyond the scope of this document. 4.4 Source/Target Link Layer Address Options Source/Target Link Layer Address Options ([RFC2461], section 4.6.1) for ISATAP have the following format: +-------+-------+-------+-------+-------+-------+-------+--------+ | Type |Length | 0 | 0 | IPv4 Address | +-------+-------+-------+-------+-------+-------+-------+--------+ Templin, et al. Expires April 14, 2004 [Page 5] Internet-Draft ISATAP October 2003 Type: 1 for Source Link-layer address. 2 for Target Link-layer address. Length: 1 (in units of 8 octets). IPv4 Address: The 32 bit IPv4 address, in network byte order. 5. Automatic Tunneling ISATAP interfaces use the basic transition mechanisms specified in [MECH] with the following exceptions: 5.1 Tunnel MTU and Fragmentation The specification in ([MECH], section 3.2) is not used; the specification in this section is used instead. The minimum MTU for IPv6 interfaces is 1280 bytes ([RFC2460], Section 5), but the following operational considerations are noted: o Nearly all IPv4 nodes connect to physical links with MTUs of 1500 bytes or larger (e.g., Ethernet) o Sub-IPv4 layer encapsulations (e.g., VPN) may occur on some paths o Commonly-deployed VPN interfaces use an MTU of 1400 bytes To maximize efficiency and minimize IPv4 fragmentation for the predominant deployment case, LinkMTU for ISATAP interfaces SHOULD be set to no more than 1380 bytes (1400 minus 20 bytes for IPv4 encapsulation). LinkMTU MAY be set to larger values when a dynamic link layer (IPv4) MTU discovery mechanism is used, or when a static MTU assignment is used and the anticipated/measured level of fragmentation in the site's IPv4 network is deemed acceptable. When a dynamic link layer MTU discovery mechanism is not used, the Don't Fragment (DF) bit MUST NOT be set in the encapsulating IPv4 header of packets sent on the ISATAP interface. In this case, black holes may in rare instances occur along some paths even when the tunnel interface uses the IPv6 minimum MTU of 1280 bytes. (This concern is not specific to ISATAP interfaces, but applies to all tunnels for which nested levels of sub link-layer encapsulation may Templin, et al. Expires April 14, 2004 [Page 6] Internet-Draft ISATAP October 2003 occur.) 5.2 Handling IPv4 ICMP Errors ARP failures and persistent ICMPv4 errors SHOULD be processed as link-specific information indicating that a path to a neighbor has failed ([RFC2461], section 7.3.3). 5.3 Link-Local Addresses The specification in ([MECH], section 3.7) is not used; the specification in Section 4.1 of this document is used instead. 5.4 Neighbor Discovery over Tunnels The specification in ([MECH], section 3.8) is not used; the specifications in Section 6 and Section 7 of this document are used instead. 5.5 Decapsulation/Filtering The specifications in ([MECH], sections 3.6, 3.9 and 4.1) are used. In addition, the decapsulator MUST determine the correct tunnel interface to receive each IPv4 protocol-41 packet via a table lookup for the tuple consisting of the packet's IPv4 source and destination address, and ifIndex for the receiving IPv4 interface. (Note that ISATAP interfaces match all IPv4 source addresses by default; if a tunnel interface with a more-specific match on the IPv4 source address exists, it is selected to receive the packet as for longest-prefix-match.) Packets for which the correct tunnel interface cannot be determined are discarded; in this case, the decapsulator MAY also send an ICMPv4 Destination Unreachable message with code 3 (Port Unreachable) ([RFC1122], section 3.2.2.1) to the IPv4 source address in the packet's outer header. After determining the correct tunnel interface, the decapsulator MUST also verify that the packet's link-layer (IPv4) source address is correct for the network-layer (IPv6) source address. For ISATAP interfaces, the packet's link-layer source address is correct if one (or more) of the following are true: o the network-layer source address is an ISATAP address that embeds the link-layer source address in its interface identifier. o the network-layer source address is an IPv6 neighbor within the same site as the receiving ISATAP interface, and the link-layer source address matches the link layer address in the neighbor Templin, et al. Expires April 14, 2004 [Page 7] Internet-Draft ISATAP October 2003 cache. o the link-layer source address is a member of the Potential Router List for the site (see: Section 6.1). Packets for which the link-layer source address is incorrect are discarded, and an ICMPv6 Destination Unreachable message ([ICMPV6], section 3.1) SHOULD be sent to the IPv6 source in the inner header of the encapsulated packet (subject to rate limiting as in [ICMPV6], section 2.4, paragraph f). 6. Neighbor Discovery ISATAP interfaces use the neighbor discovery mechanisms specified in [RFC2461] with the following exceptions: 6.1 Conceptual Model Of A Host To the list of Conceptual Data Structures ([RFC2461], section 5.1), ISATAP interfaces add: Potential Router List A set of entries about potential routers for the site; used to support the mechanisms specified in Section 6.2.3. Each entry ("PRL(i)") has an associated timer ("TIMER(i)"), and an IPv4 address ("V4ADDR(i)") that represents a router's advertising ISATAP interface. 6.2 Router and Prefix Discovery 6.2.1 Message Validation 6.2.1.1 Validation of Router Solicitation Messages To the list of validity checks for Router Soliciation messages ([RFC2461], section 6.1.1), ISATAP interfaces add: o If the message includes a Source Link Layer Address Option, the message also includes an IP authentication Header. 6.2.1.2 Validation of Router Advertisement Messages To the list of validity checks for Router Advertisement messages ([RFC2461], section 6.1.1), ISATAP interfaces add: Templin, et al. Expires April 14, 2004 [Page 8] Internet-Draft ISATAP October 2003 o IP Source Address is an ISATAP link-local address that embeds V4ADDR(i) for some PRL(i). o If the message includes a Source Link Layer Address Option, the message also includes an IP authentication Header. 6.2.2 Router Specification As permitted by ([RFC2461], section 6.2.6), advertising ISATAP interfaces SHOULD unicast Router Advertisement messages to the soliciting host's address when the solicitation's source address is not the unspecified address. 6.2.3 Host Specification 6.2.3.1 Host Variables To the list of host variables ([RFC2461], section 6.3.2), ISATAP interfaces add: PrlRefreshInterval Time in seconds between successive refreshments of the PRL after initialization. It SHOULD be no less than 3600 seconds. The designated value of all 1's (0xffffffff) represents infinity. Default: 3600 seconds MinRouterSolicitInterval Minimum time in seconds between successive solicitations of the same advertising ISATAP interface. It SHOULD be no less than 900 seconds. The designated value of alll 1's (0xffffffff) represents infinity. Default: 900 seconds 6.2.3.2 Interface Initialization The host joins the all-nodes multicast address on ISATAP interfaces, as for multicast-capable interfaces ([RFC2461], section 6.3.3). Additionally, the host provisions the ISATAP interface's PRL with IPv4 addresses it discovers via manual configuration, a DNS fully-qualified domain name (FQDN) [RFC1035], a DHCPv4 option for ISATAP [ISDHCP], a DHCPv4 vendor-specific option, or an unspecified alternate method. (Support for manual configuration is REQUIRED; other methods are OPTIONAL.) Templin, et al. Expires April 14, 2004 [Page 9] Internet-Draft ISATAP October 2003 When FQDNs are used, the host establishes the FQDN via manual configuration or an unspecified alternate method. (Support for manual configuration is REQUIRED; other methods are OPTIONAL.) The host resolves the FQDN into IPv4 addresses through lookup in a static host file, a site-specific name service, querying the site's DNS service, or an unspecified alternate method. When DNS is used, client resolvers use the IPv4 transport. After the host provisions the ISATAP interface's PRL with IPv4 addresses, it sets PrlRefreshIntervalTimer to PrlRefreshInterval seconds. The host re-initializes the PRL (i.e., as specified above) when PrlRefreshIntervalTimer expires, or when an asynchronous re-initialization event occurs. When the host re-initializes the PRL, it resets PrlRefreshIntervalTimer to PrlRefreshInterval seconds. 6.2.3.3 Processing Received Router Advertisements Router Advertisements (RAs) are processed exactly as specified in ([RFC2461], section 6.3.4) except that, if the MTU option is present, the option's value SHOULD be stored in a per-neighbor cache entry for the source of the RA; it MUST NOT be copied into LinkMTU for the ISATAP interface. Additionally, hosts reset TIMER(i) to schedule the next solicitation event (see: Section 6.2.3.4). Let "MIN_LIFETIME" be the minimum value in the Router Lifetime or the lifetime(s) encoded in options included in the RA message. Then, TIMER(i) is reset as follows: TIMER(i) = MAX((0.5 * MIN_LIFETIME), MinRouterSolicitInterval) 6.2.3.4 Sending Router Solicitations To the list of events after which RSs may be sent ([RFC2461], section 6.3.2), ISATAP interfaces add: o TIMER(i) for some PRL(i) expires. Additionally, hosts MAY send Router Solicitations to an ISATAP link-local address that embeds V4ADDR(i) for some PRL(i) instead of the All-Routers multicast address. 6.3 Address Resolution and Neighbor Unreachability Detection 6.3.1 Message Validation Templin, et al. Expires April 14, 2004 [Page 10] Internet-Draft ISATAP October 2003 6.3.1.1 Validation of Neighbor Solicitations To the list of validity checks for Neighbor Solicitation (NS) messages ([RFC2461], section 7.1.1), ISATAP interfaces add: o If the message includes a Source Link Layer Address Option, the message also includes an IP authentication Header. 6.3.1.2 Validation of Neighbor Solicitations To the list of validity checks for Neighbor Advertisement (NA) messages ([RFC2461], section 7.1.2), ISATAP interfaces add: o If the message includes a Target Link Layer Address Option, the message also includes an IP authentication Header. 6.3.2 Address Resolution The specification in ([RFC2461], section 7.2) is used. NS and NA messages MAY omit the source/target link layer address option when the source/target is an ISATAP address. ISATAP addresses for which the neighbor's link-layer address cannot otherwise be determined (i.e., from the neighbor cache or a link layer address option in a received packet) are resolved to link-layer addresses by a static computation, i.e., the last four octets are treated as an IPv4 address. Hosts SHOULD perform an initial reachability confirmation by sending NS message(s) and receiving a NA message; NS messages are sent to the target's unicast address. Routers MAY perform an initial reachability confirmation, but this might not scale in all environments. As specified in ([RFC2461], section 7.2.4), all nodes MUST send solicited neighbor advertisements on ISATAP interfaces. 6.3.3 Neighbor Unreachability Detection Hosts SHOULD perform Neighbor Unreachability Detection as specified in ([RFC2461], section 7.3). Routers MAY perform neighbor unreachability detection, but this might not scale in all environments. 6.4 Redirect Function To the list of validity checks for Redirect messages (([RFC2461], section 8.1), ISATAP interfaces add: Templin, et al. Expires April 14, 2004 [Page 11] Internet-Draft ISATAP October 2003 o If the message includes a Target Link Layer Address Option, the message also includes an IP authentication Header. 7. Address Autoconfiguration ISATAP interfaces use the address autoconfiguration mechanisms specified in [RFC2462] with the following exceptions: 7.1 Address Lifetime Expiry The specification in ([RFC2462], section 5.5.4) is used, except that an ISATAP address also becomes deprecated when the IPv4 address embedded in its interface identifier is removed from an IPv4 interface over which the ISATAP interface is configured. (This deprecation rule applies to all ISATAP addresses, including link-local addresses.) 7.2 Stateful Address Autoconfiguration When the site uses DHCPv6 [RFC3315] as the stateful address autoconfiguration mechanism, the server/relay function MUST be deployed equally on each router that is a member of the PRL. 8. IANA Considerations The IANA is advised to specify construction rules for IEEE EUI-64 addresses formed from the Organizationally Unique Identifier (OUI) "00-00-5E" in the IANA "ethernet-numbers" registry. The non-normative text in Appendix B is offered as an example specification. 9. Security considerations The security considerations in [RFC2461][RFC2462][MECH] apply. Additionally, site administrators MUST ensure that lists of IPv4 addresses representing the advertising ISATAP interfaces of PRL members are well maintained. 10. Acknowledgments Most of the basic ideas in this document are not original; the authors acknowledge the original architects of those ideas. Portions of this work were sponsored through SRI International internal projects and government contracts. Government sponsors include Monica Farah-Stapleton and Russell Langan (U.S. Army CECOM ASEO), and Dr. Allen Moshfegh (U.S. Office of Naval Research). SRI International sponsors include Dr. Mike Frankel, J. Peter Marcotullio, Lou Templin, et al. Expires April 14, 2004 [Page 12] Internet-Draft ISATAP October 2003 Rodriguez, and Dr. Ambatipudi Sastry. The following are acknowledged for providing peer review input: Jim Bound, Rich Draves, Cyndi Jung, Ambatipudi Sastry, Aaron Schrader, Ole Troan, Vlad Yasevich. The following are acknowledged for their significant contributions: Alain Durand, Hannu Flinck, Jason Goldschmidt, Nathan Lutchansky, Karen Nielsen, Mohan Parthasarathy, Chirayu Patel, Art Shelest, Pekka Savola, Margaret Wasserman, Brian Zill. The authors acknowledge the work of Quang Nguyen [VET] under the guidance of Dr. Lixia Zhang that proposed very similar ideas to those that appear in this document. This work was first brought to the authors' attention on September 20, 2002. Normative References [ADDR-ARCH] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", draft-ietf-ipv6-addr-arch-v4-00 (work in progress), October 2003. [ICMPV6] Conta, A. and S. Deering, "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification", draft-ietf-ipngwg-icmp-v3 (work in progress), November 2001. [MECH] Gilligan, R. and E. Nordmark, "Basic Transition Mechanisms for IPv6 Hosts and Routers", draft-ietf-v6ops-mech-v2-00 (work in progress), February 2003. [MIB] Thaler, D., "IP Tunnel MIB", draft-thaler-inet-tunnel-mib (work in progress), September 2003. [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998. [RFC2461] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. Templin, et al. Expires April 14, 2004 [Page 13] Internet-Draft ISATAP October 2003 [RFC2462] Thomson, S. and T. Narten, "IPv6 Stateless Address Autoconfiguration", RFC 2462, December 1998. Informative References [ISDHCP] Templin, F., "Dynamic Host Configuration Protocol (DHCPv4) Option for the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)", draft-templin-isatap-dhcp (work in progress), October 2003. [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC1122] Braden, R., "Requirements for Internet Hosts - Communication Layers", STD 3, RFC 1122, October 1989. [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G. and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996. [RFC2491] Armitage, G., Schulter, P., Jork, M. and G. Harter, "IPv6 over Non-Broadcast Multiple Access (NBMA) networks", RFC 2491, January 1999. [RFC2529] Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4 Domains without Explicit Tunnels", RFC 2529, March 1999. [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: Defeating Denial of Service Attacks which employ IP Source Address Spoofing", BCP 38, RFC 2827, May 2000. [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB", RFC 2863, June 2000. [RFC3041] Narten, T. and R. Draves, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 3041, January 2001. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [RFC3582] Abley, J., Black, B. and V. Gill, "Goals for IPv6 Site-Multihoming Architectures", RFC 3582, August 2003. [VET] Nguyen, Q., "http://irl.cs.ucla.edu/vet/report.ps", spring 1998. Templin, et al. Expires April 14, 2004 [Page 14] Internet-Draft ISATAP October 2003 Authors' Addresses Fred L. Templin Nokia 313 Fairchild Drive Mountain View, CA 94110 US Phone: +1 650 625 2331 EMail: ftemplin@iprg.nokia.com Tim Gleeson Cisco Systems K.K. Shinjuku Mitsu Building 2-1-1 Nishishinjuku, Shinjuku-ku Tokyo 163-0409 Japan EMail: tgleeson@cisco.com Mohit Talwar Microsoft Corporation One Microsoft Way Redmond, WA> 98052-6399 US Phone: +1 425 705 3131 EMail: mohitt@microsoft.com Dave Thaler Microsoft Corporation One Microsoft Way Redmond, WA 98052-6399 US Phone: +1 425 703 8835 EMail: dthaler@microsoft.com Appendix A. Major Changes Major changes from earlier versions to version 16: o dropped "underlying link" from terminology. o specified multicast mappings. Templin, et al. Expires April 14, 2004 [Page 15] Internet-Draft ISATAP October 2003 o specified layer address option format. o specified setting of "u" bit in interface id's. o removed obsoleted appendix sections. o re-organized major sections to match normative references. o revised neighbor discovery, address autoconfiguration, security considerations sections. Added new subsections on interface management, decapsulation/filtering, address lifetime expiry. Appendix B. Interface Identifier Construction This section provides an example specification for constructing EUI64 addresses from the Organizationally-Unique Identifier (OUI) owned by the Internet Assigned Numbers Authority (IANA). It can be used to construct both modified EUI-64 format interface identifiers for IPv6 unicast addresses ([ADDR-ARCH], section 2.5.1) and "native" EUI64 addresses for future use: |0 2|2 3|3 3|4 6| |0 3|4 1|2 9|0 3| +------------------------+--------+--------+------------------------+ | OUI ("00-00-5E"+u+g) | TYPE | TSE | TSD | +------------------------+--------+--------+------------------------+ Where the fields are: OUI IANA's OUI: 00-00-5E with "u" and "g" bits (3 octets) TYPE Type field; specifies use of (TSE, TSD) (1 octet) TSE Type-Specific Extension (1 octet) TSD Type-Specific Data (3 octets) And the following interpretations are specified based on TYPE: TYPE (TSE, TSD) Interpretation ---- ------------------------- 0x00-0xFD RESERVED for future IANA use 0xFE (TSE, TSD) together contain an IPv4 address 0xFF TSD is interpreted based on TSE as follows: TSE TSD Interpretation --- ------------------ Templin, et al. Expires April 14, 2004 [Page 16] Internet-Draft ISATAP October 2003 0x00-0xFD RESERVED for future IANA use 0xFE TSD contains 24-bit EUI-48 intf id 0xFF RESERVED by IEEE/RAC Using this example specification, if TYPE=0xFE, then TSE is an extension of TSD. If TYPE=0xFF, then TSE is an extension of TYPE. (Other values for TYPE, and other interpretations of TSE, TSD are reserved for future IANA use.) When TYPE='0xFE' the EUI64 address embeds an IPv4 address, encoded in network byte order. For Modified EUI64 format interface identifiers in IPv6 unicast addresses ([ADDR-ARCH], Appendix A) using IANA's OUI, when TYPE=0xFE and the IPv4 address is a globally unique (i.e., provider-assigned) unicast address, the "u" bit is set to 1 to indicate universal scope. When TYPE=0xFE and the IPv4 address is from a private allocation, the "u" bit is set to 0 to indicate local scope. Thus, when the first four octets of the interface identifier in an IPv6 unicast address are either: '02-00-5E-FE' or: '00-00-5E-FE', the next four octets embed an IPv4 address and the interface identifier is said to be in "ISATAP format". Templin, et al. Expires April 14, 2004 [Page 17] Internet-Draft ISATAP October 2003 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. 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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 assignees. Templin, et al. Expires April 14, 2004 [Page 18] Internet-Draft ISATAP October 2003 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Templin, et al. Expires April 14, 2004 [Page 19]