IPv6 ND PIO Flags IANA considerations draft-ietf-6man-ndpioiana-02 Reviewer: Al Morton Review Result: Almost Ready/Has Nits I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review. Document editors and WG chairs should treat these comments just like any other last call comments. Summary: Mobile IPv6 extends Neighbor Discovery to allow a router to advertise its global address, by the addition of a single flag bit in the format of a Prefix Information option for use in Router Advertisement messages. RFC6275 modified the original RFC4861 Neighbor Discovery (ND) Prefix Information Option format, allocating a "Reserved1" bit to "R" for this purpose, but did not establish an IANA registry to track such extensions (and did not indicate this as an update of RFC4681, possibly creating issues for further allocation of the "Reserved1" bits (note that there are two Reserved fields in the Prefix Information Option, the other is denoted "Reserved2"). This memo requests IANA to create a new registry that brings the extension of "Reserved1" bits under control, and therefore solves a potential future Operations problem. Suggestions in Section 4, IANA Considerations: Usually, the reserved bits are indicated in the Registry: +---------------+---------------------------------+-----------+ | RA Option Bit | Description | Reference | +---------------+---------------------------------+-----------+ | 0 | L - On-link Flag | [RFC4861] | | 1 | A - Autonomous Address | [RFC4861] | | | Configuration Flag | | | 2 | R - Router Address Flag | [RFC6275] | +---------------+---------------------------------+-----------+ | | 3-7 | Reserved1 | [RFC6275] | +---------------+---------------------------------+-----------+ Figure 2 Also, it is useful to indicate the Registration Procedure in this section, such as: Registration Procedure(s) Standards Action or IESG Approval (IANA will ask for this, and may ask for the explicit registry name, too) Nits: Updates: 4861 (and also 6275, by establishing the ND PIO Flag registry, right?) Introduction: two explicit section references would have been helpful, such as https://tools.ietf.org/html/rfc4861#section-4.6.2 https://tools.ietf.org/html/rfc6275#section-7.2 as both are long RFCs. regards, Al