Internet Engineering Task Force (IETF) O. Troan Request for Comments: 8425 Cisco Systems Updates: 4861 July 2018 Category: Standards Track ISSN: 2070-1721IANA Considerations for IPv6 Neighbor Discovery Prefix Information Option Flags
Troan Standards Track [Page 1]
RFC 8425 IANA Considerations for PIO Flags July 2018
Table of Contents
1. Introduction
The Prefix Information Option (PIO) in the IPv6 Neighbor Discovery Router Advertisement message defines an 8-bit flag field; this field has two flags defined and the remaining 6 bits are reserved (Reserved1). RFC 6275 defines a flag from this field without creating an IANA registry or updating RFC 4861. The purpose of this document is to create a new registry for the PIO flags.
2. Current Prefix Information Option Flags
Currently, the Neighbor Discovery Protocol Prefix Information Option [RFC4861] contains the following one-bit flags defined in published RFCs:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|L|A|R|Reserved1|
+-+-+-+-+-+-+-+-+
Figure 1: PIO Flags
Troan Standards Track [Page 2]
RFC 8425 IANA Considerations for PIO Flags July 2018 3. Updates to RFC 4861This document updates Section 4.6.2 "Prefix Information" of [RFC4861] to point to the IANA registry that is created in this document (see Section 4).
4. IANA Considerations
IANA has created a new registry for IPv6 Neighbor Discovery Prefix Information Option flags. This registry includes the current flags in the PIO. The initial contents of the registry are as follows:
+----------------+---------------------------------+-----------+
| PIO 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 | Reserved | |
+----------------+---------------------------------+-----------+
Figure 2: IPv6 Neighbor Discovery Prefix Information Option Flags
5. Security Considerations
This document has no security considerations.
Troan Standards Track [Page 3]
RFC 8425 IANA Considerations for PIO Flags July 2018 6. Normative References[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,