| Internet-Draft | Generic Identifier | August 2022 |
| Iurman | Expires 7 February 2023 | [Page] |
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 note is to be removed before publishing as an RFC.¶
The latest revision of this draft can be found at https://IurmanJ.github.io/draft-iurman-6man-generic-id/draft-iurman-6man-generic-id.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-iurman-6man-generic-id/.¶
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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.¶
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.¶
For simple use cases where an ID is carried without extra fields and without any specific context, a new option type "Generic ID" is defined to carry such ID generically in IPv6 packets, as defined below:¶
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
¶
where:¶
Note: as an example, both [I-D.draft-ietf-6man-enhanced-vpn-vtn-id-00] and [I-D.draft-li-6man-topology-id] should use this option to carry IDs they define respectively.¶
For other use cases where an ID is carried with extra fields or when a context is required, a new option type "Generic Context-ID" is defined to carry such ID generically in IPv6 packets, as defined below:¶
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
¶
where:¶
Note: as an example, [I-D.draft-ietf-6man-enhanced-vpn-vtn-id] should use this option to carry the 16-bit ID and flags it defines.¶
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:¶
The subsequent subsections detail the registries therein contained.¶
This registry defines 65535 code points for the Context-Type field to identify the type of context. The following code points are defined in this document:¶
Other code points are available for assignment via the "IETF Review" process, as per [RFC8126].¶
New registration requests MUST use the following template:¶
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.¶