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diff --git a/doc/rfc/rfc2497.txt b/doc/rfc/rfc2497.txt new file mode 100644 index 0000000..9321879 --- /dev/null +++ b/doc/rfc/rfc2497.txt @@ -0,0 +1,339 @@ + + + + + + +Network Working Group I. Souvatzis +Request for Comments: 2497 The NetBSD Project +See Also: 1201 January 1999 +Category: Standards Track + + + Transmission of IPv6 Packets over ARCnet Networks + +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 (1999). All Rights Reserved. + +1. Introduction + + This memo specifies a frame format for transmission of IPv6 [IPV6] + packets and the method of forming IPv6 link-local and statelessly + autoconfigured addresses on ARCnet networks. It also specifies the + content of the Source/Target Link-layer Address option used by the + Router Solicitation, Router Advertisement, Neighbor Solicitation, + Neighbor Advertisement and Redirect messages described in [DISC], + when those messages are transmitted on an ARCnet. + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL + NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" + in this document are to be interpreted as described in RFC 2119 + [KWORD]. + +2. Frame Format + + IPv6 packets are link layer fragmented and reassembled according to + [PHDS]. A brief but sufficient discussion of this fragmentation + method can be found in [ARCIPV4]. + + The protocol ID (System Code in ARCnet terminology) assigned to IPv6 + is C4 hexadecimal. + + + + + + + + +Souvatzis Standards Track [Page 1] + +RFC 2497 IPv6 Datagrams on ARCnet January 1999 + + +3. Maximum Transmission Unit + + The maximum IPv6 packet length possible using this encapsulation + method is 60480 octets. Since this length is impractical because of + its worst case transmission time of several seconds, all ARCnet + implementations on a given ARCnet network should agree on a smaller + value. + + The default MTU for IPv6 [IPV6] packets on an ARCnet is 9072 octets. + + In the presence of a router, this size MAY be changed by a Router + Advertisement [DISC] containing an MTU option. If a Router + Advertisement is received with an MTU option specifying an MTU larger + than 60480, or larger than a manually configured value less than + 60480, that MTU option may be logged to system management but MUST be + otherwise ignored. + + If no router is available, the local MTU MUST be left at 9072 or MUST + be manually configured to the same different value on all connected + stations. + + Implementations MAY accept arriving IPv6 datagrams which are larger + than their configured maximum transmission unit. They are not + required to discard such datagrams. If they can not handle larger + datagrams, they MAY log the event to the system administration, but + MUST otherwise silently discard them. + +4. Stateless Auto-configuration + + If a node has an EUI-64 which is not used to form the Interface + Identifier for any other interface, it SHOULD use that EUI-64 to form + the Interface Identifier for its ARCnet interface. If that EUI-64 is + in use for another interface attached to a different link, it MAY be + used for the ARCnet interface as well. + + The Interface Identifier is then formed from the EUI-64 by + complementing the "Universal/Local" (U/L) bit, which is the next- + to-lowest order bit of the first octet of the EUI-64. + + When a node has no EUI-64 available for forming its ARCnet Interface + Identifer, it MUST form that identifier as specified in [AARCH], + Appendix A, section "Links with Non-Global Identifier". That is, the + 8 bit manually configured ARCnet address is appended to the 56 zero + bits. + + For example, for an ARCnet interface with the configured address of + 49 hexadecimal this results in the following identifier: + + + + +Souvatzis Standards Track [Page 2] + +RFC 2497 IPv6 Datagrams on ARCnet January 1999 + + + |0 1|1 3|3 4|4 6| + |0 5|6 1|2 7|8 3| + +----------------+----------------+----------------+----------------+ + |0000000000000000|0000000000000000|0000000000000000|0000000001001001| + +----------------+----------------+----------------+----------------+ + + Note that this results in the universal/local bit set to "0" to + indicate local scope. + + An IPv6 address prefix used for stateless auto-configuration [ACONF] + of an ARCnet interface MUST have a length of 64 bits. + +5. Link-Local Addresses + + The IPv6 link-local address [AARCH] for an ARCnet interface is formed + by appending the Interface Identifier, as defined above, to the + prefix FE80::/64. + + 10 bits 54 bits 64 bits + +----------+-----------------------+----------------------------+ + |1111111010| (zeros) | Interface Identifier | + +----------+-----------------------+----------------------------+ + +6. Address Mapping -- Unicast + + The procedure for mapping IPv6 addresses into ARCnet link-layer + addresses is described in [DISC]. The Source/Target link layer + Address option has the following form when the link layer is ARCnet. + + 0 1 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |ARCnet address | | + +---------------+ -+ + | | + +- 5 octets of padding -+ + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Option fields: + + Type 1 for Source Link-layer address. + 2 for Target Link-layer address. + Length 1 (in units of 8 octets). + + ARCnet address The 8 bit ARCnet address, in canonical bit order. + + + +Souvatzis Standards Track [Page 3] + +RFC 2497 IPv6 Datagrams on ARCnet January 1999 + + +7. Address Mapping -- Multicast + + As ARCnet only provides 1 multicast address (00 hexadecimal), all + IPv6 multicast addresses MUST be mapped to this address. + +8. Security Considerations + + The method of derivation of Interface Identifiers from ARCnet + addresses is intended to preserve local uniqueness when possible. + However, there is no protection from duplication through accident or + forgery. + +9. Acknowledgements + + Big parts of the new version of this memo are either based on + [ETHIPV6] or on Matt Crawford's review of an earlier version. + +10. References + + [AARCH] Hinden, R. and S. Deering, "IP Version 6 Addressing + Architecture", RFC 2373, July 1998. + + [ACONF] Thomson, S. and T. Narten, "IPv6 Stateless Address + Autoconfiguration", RFC 2462, December 1998. + + [ARCIPV4] Provan, D., "Transmitting IP Traffic over ARCNET Networks", + RFC1201, Novell, Inc., February 1991. + + [DISC] Narten, T., Nordmark, E. and W. Simpson, "Neighbor + Discovery for IP Version 6 (IPv6)", RFC 2461, December + 1998. + + [ETHIPV6] Crawford, M., "Transmission of IPv6 Packets over Ethernet + Networks", RFC 2464, December 1998. + + [EUI64] "64-Bit Global Identifier Format Tutorial", http://stan + dards.ieee.org/db/oui/tutorials/EUI64.html. + + [IPV6] Deering, S. and R. Hinden, "Internet Protocol, Version 6 + (IPv6) Specification", RFC 2460, December 1998. + + [KWORD] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [PHDS] Novell, Inc., "ARCNET Packet Header Definition Standard", + Novell Part Number 100-00721-001, November 1989. + + + + + +Souvatzis Standards Track [Page 4] + +RFC 2497 IPv6 Datagrams on ARCnet January 1999 + + +11. Author's Address + + Ignatios Souvatzis + The NetBSD Project + Stationenweg 29 + D-53332 Bornheim + Germany + + Phone (work): +49 (228) 734316 + EMail: is@netbsd.org + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Souvatzis Standards Track [Page 5] + +RFC 2497 IPv6 Datagrams on ARCnet January 1999 + + +12. Full Copyright Statement + + Copyright (C) The Internet Society (1999). 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. + + + + + + + + + + + + + + + + + + + + + + + + +Souvatzis Standards Track [Page 6] + |