Agree with Carsten here. The referenced RFC 2464 complements the U/L bit when an EUI-64 is converted into an interface identifier. So the meaning of the U/L bit is also reversed in the interface identifier so it differs from the values as written in the IEEE "Guidelines for EUI-64" document.
Just noting that the naming in RFC 4944 may confuse some readers: both bits are now named "U/L bit". The complemented bit could have been named "L/U bit" instead; or "the bit in the U/L bit position". Also the RFC 2464 reference URL to the "Guidelines for EUI-64" document is not valid anymore. There's a 2017 version located at: https://standards.ieee.org/wp-content/uploads/import/documents/tutorials/eui.pdf Esko -----Original Message----- From: 6lo <[email protected]> On Behalf Of Carsten Bormann Sent: Tuesday, April 23, 2024 21:22 To: Eric Vyncke (evyncke) <[email protected]> Cc: [email protected] Subject: Re: [6lo] Processing old erratum 6194 on RFC 4944, "Transmission of IPv6 Packets over IEEE 802.15.4 Networks" RFC 4944 does what (AFAIK) all 802-derived IP-over-foos do when creating IP addresses from MAC addresses/EUIs: The Interface Identifier is then formed from the EUI-64 by complementing the "Universal/Local" (U/L) bit, (Section 4 of RFC 2464). The text cited from IEEE talks about EUIs. EUIs need to have the bit complemented to build the Interface Identifier. So the U/L bit in the IID is inverted from that sense, i.e., 0 for local and 1 for universal. This semantics also applies to IIDs built from 16-bit addresses, which are never globally unique, and therefore always have the bit set to 0 (local). The text in RFC 4944 is as intended. Grüße, Carsten > On 23. Apr 2024, at 15:40, Eric Vyncke (evyncke) > <[email protected]> wrote: > > As the new shepherding AD for 6LO, I just found a reported (i.e., neither > verified nor closed) erratum on RFC 4944, "Transmission of IPv6 Packets over > IEEE 802.15.4 Networks". > https://www.rfc-editor.org/errata_search.php?eid=6194This erratum was never > posted to the 6LO list probably due to a technical issue. > What is the WG view on this erratum ? > Thank you in advance for the discussion. > Regards > -éric > The reported errata is: > Reported By: Tommaso Pecorella > Date Reported: 2020-05-30 > Section 6 says: > However, in the > resultant interface identifier, the "Universal/Local" (U/L) bit SHALL > be set to zero in keeping with the fact that this is not a globally > unique value. > It should say: > However, in the > resultant interface identifier, the "Universal/Local" (U/L) bit SHALL > be set to one in keeping with the fact that this is not a globally > unique value. > Notes: > IEEE (see > https://standards.ieee.org/content/dam/ieee-standards/standards/web/documents/tutorials/eui.pdf) > states that: > "the second least significant bit of Octet 0 (the U/L bit) indicates > universal (U/L=0) or local (U/L=1) administration of the address." > Thus, the U/L bit in the "pseudo 48-bit address" shall have its U/L bit set > to one, not to zero. > _______________________________________________ > 6lo mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6lo _______________________________________________ 6lo mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lo _______________________________________________ 6lo mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lo
