RFC 8425

IANA Considerations for IPv6 Neighbor Discovery Prefix Information Option Flags

📅 published July 2018, from ietf

RFC 8425: IANA Considerations for IPv6 Neighbor Discovery Prefix Information Option Flags 🎀

Okay bestie, let's start with the title block 💅 This is RFC 8425 from the Internet Engineering Task Force (IETF), written by O. Troan at Cisco Systems. It's dated July 2018 and it's a Standards Track document (ISSN 2070-1721). The big deal is that it updates RFC 4861 🔥 It doesn't list anything it obsoletes.

Abstract ✨

Okay so the Prefix Information Option (PIO) in the IPv6 Neighbor Discovery Router Advertisement message has an 8-bit flag field 🦋 Only two flags are defined in it, and the other 6 bits are reserved (Reserved1). RFC 6275 defines a flag in this field without making an IANA registry or updating RFC 4861, which is lowkey messy. So this doc makes an IANA registry for the PIO flags 🧚 It also updates RFC 4861.

Status of This Memo 📜

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It got public review and was approved for publication by the Internet Engineering Steering Group (IESG). If you want more on Internet Standards, check out Section 2 of RFC 7841.

Info about the current status of this document, any errata, and how to give feedback on it lives at https://www.rfc-editor.org/info/rfc8425 🌸

Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) as they stand on the publication date. Read these carefully, because they spell out your rights and restrictions for this doc. Code Components taken from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions, and they come without warranty as described in the Simplified BSD License 🫶

Table of Contents 🗂️

1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
2.  Current Prefix Information Option Flags . . . . . . . . . . .   2
3.  Updates to RFC 4861 . . . . . . . . . . . . . . . . . . . . .   3
4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
5.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
6.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1. Introduction 🌈

Okay so the PIO in the IPv6 Neighbor Discovery Router Advertisement message has an 8-bit flag field. Two flags are defined and the remaining 6 bits are reserved (Reserved1) 🙈 RFC 6275 defines a flag from this field without making an IANA registry or updating RFC 4861. The whole point of this doc is to make a new registry for the PIO flags, so the list has a home ✨

2. Current Prefix Information Option Flags 🦋

Right now, the Neighbor Discovery Protocol Prefix Information Option [RFC4861] has these one-bit flags in published RFCs, and this is the layout bestie 👑

                             0 1 2 3 4 5 6 7
                            +-+-+-+-+-+-+-+-+
                            |L|A|R|Reserved1|
                            +-+-+-+-+-+-+-+-+

                          Figure 1: PIO Flags
  • L - On-link Flag [RFC4861] 🍓
  • A - Autonomous Address Configuration Flag [RFC4861] 🌸
  • R - Router Address Flag [RFC6275] 💖
  • Reserved1 - Reserved 🫧

3. Updates to RFC 4861 💅

This doc updates Section 4.6.2 "Prefix Information" of [RFC4861] so it points to the IANA registry this doc creates (see Section 4). It's giving cross-referencing energy 🔥

To be specific, the current list of flags in the Prefix Information Option is found in the "IPv6 Neighbor Discovery Prefix Information Option Flags" registry 🧚

4. IANA Considerations 📚

IANA made a brand new registry for IPv6 Neighbor Discovery Prefix Information Option flags 🎀 It includes the current PIO flags. Here's what's in it at the start:

    +----------------+---------------------------------+-----------+
    | 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

Adding a new flag to the PIO option header needs Standards Action [RFC8126] 👑 Ngl, that's the gatekeeping we love to see 💀

The registry for these flags is at <http://www.iana.org/assignments/icmpv6-parameters> 🌈

5. Security Considerations 🙈

This document has no security considerations. Not a single one 🫶

6. Normative References 📖

Author's Address 💌

Ole Troan
Cisco Systems
Philip Pedersens vei 1
Lysaker  1366
Norway

Email: ot@cisco.com

That's the whole RFC, bestie 🌈💖✨

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