Carrying a Generic Identifier in IPv6 packets

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Table of Contents

1. Introduction

Some recent use cases seem to have a need for carrying IDs within packets. Two examples are [I-D.draft-ietf-6man-enhanced-vpn-vtn-id] and [I-D.draft-li-6man-topology-id]. While they might perfectly make sense on their own, each document requires IANA to allocate a new code point for a new option, which could quickly exhaust the allocation space if similar designs are proposed in the future. As an example, one might need an 8-bit ID, while another one might need a 24-bit, 32-bit, or 64-bit ID. Or, even worse, one might need a 32-bit ID in a specific context, while someone else might also need a 32-bit ID in another context. Therefore, allocating a new code point for each similar option is probably not the way to go.¶

This document proposes a solution to carry IDs generically to avoid the problem mentioned previously. Two new Hop-by-Hop and Destination options are defined, called "Generic ID Option" and "Generic Context-ID Option". Both are defined and explained in this document.¶

2. Conventions and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

3. New IPv6 Destination and Hop-by-Hop Options

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
                                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                    |  Option Type  |  Opt Data Len |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    ~                  Generic ID (variable length)                 ~
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 1. Generic ID Option

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
                                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                    |  Option Type  |  Opt Data Len |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |         Context-Type          |           Reserved            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    ~                Context Data (variable length)                 ~
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                   Figure 2. Generic Context-ID Option

4. IANA Considerations

This document requests the following IPv6 Option Type assignments from the Destination Options and Hop-by-Hop Options sub-registry of Internet Protocol Version 6 (IPv6) Parameters.¶

http://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2¶

    Binary Value     Description                   Reference
    act chg rest
    --------------------------------------------------------------
    00   0  TBD      Generic ID Option             [This document]
    00   0  TBD      Generic Context-ID Option     [This document]

This document also requests IANA to define a registry group named "Generic Context-ID".¶

This group includes the following registries:¶

• Context-Type¶

The subsequent subsections detail the registries therein contained.¶

5. Security Considerations

As this document describes new options for IPv6, these are similar to the security considerations of [RFC8200] and the weakness documented in [RFC8250].¶

This document does not define the data contents of custom Generic Context-ID options. These custom options will have security considerations corresponding to their defined data contents that need to be described where those formats are defined.¶

Acknowledgments

Author's Address