| Internet-Draft | Carrying an Identifier in IPv6 packets | February 2023 |
| Iurman | Expires 12 August 2023 | [Page] |
Some recent use cases have a need for carrying an identifier in IPv6 packets. While those drafts might perfectly make sense on their own, each document requires IANA to allocate a new code point for a new option, and so for very similar situations, 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 32-bit, 64-bit or 128-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-carry-identifier/draft-iurman-6man-carry-identifier.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-iurman-6man-carry-identifier/.¶
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Source for this draft and an issue tracker can be found at https://github.com/IurmanJ/draft-iurman-6man-carry-identifier.¶
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Some recent use cases have a need for carrying an identifier in IPv6 packets. Two examples are [I-D.draft-ietf-6man-enhanced-vpn-vtn-id] and [I-D.draft-li-6man-topology-id]. While those drafts might perfectly make sense on their own, each document requires IANA to allocate a new code point for a new option, and so for very similar situations, 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 32-bit, 64-bit or 128-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 two different solutions to carry an identifier in IPv6 packets, in order to avoid the aforementioned issue. Each solution defines a new option in the Destination Options and Hop-by-Hop Options sub-registry. Both are 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 such as a single identifier carried without additional fields and without specific context, a new Option Type named "Generic Identifier" is defined as follows:¶
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Identifier (variable length) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1. Generic Identifier Option
¶
where:¶
(+) Totally generic solution, similar to an Identifier container.¶
(-) Too generic, as it could be used to carry all and nothing.
(-) No context for the carried identifier, which might disturb the receiver.
(-) No multiple identifiers, where some use cases might need to carry more than
one.
(-) No additional fields, where some use cases might need that.¶
For use cases where one or several identifiers are carried with additional fields, or when a context is required, a new Option Type named "Identifier with Context" is defined as follows:¶
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-ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Context-Data (variable length) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2. Identifier with Context Option
¶
where:¶
(+) Allows for a context.
(+) Allows for multiple identifiers.
(+) Allows for additional fields.
(+) IETF review process for new Context-ID code points.¶
(-) Not hardware friendly.¶
If the solution is adopted, this document requests IANA to allocate the following IPv6 Option Type in the Destination Options and Hop-by-Hop Options sub-registry of Internet Protocol Version 6 (IPv6) Parameters:¶
Binary Value Description Reference
act chg rest
--------------------------------------------------------------
00 0 TBD Generic Identifier Option [This document]
¶
If the solution is adopted, this document requests IANA to allocate the following IPv6 Option Type in the Destination Options and Hop-by-Hop Options sub-registry of Internet Protocol Version 6 (IPv6) Parameters:¶
Binary Value Description Reference
act chg rest
--------------------------------------------------------------
00 0 TBD Identifier with Context Option [This document]
¶
This document also requests IANA to define a registry group named "Identifier with Context". The following subsections detail the registries therein contained.¶
This registry defines 65536 code points for the Context-ID field, in order to know the context. The following code points are defined in this document:¶
Code point Description Reference
+--------+--------------------------+-----------------+
| 0x0000 | Reserved | This document |
+--------+--------------------------+-----------------+
| 0x0001 | | |
| .... | Unassigned | |
| 0xffef | | |
+--------+--------------------------+-----------------+
| 0xfff0 | | |
| .... | RFC3692-style Experiment | [RFC8126] |
| 0xfffe | | |
+--------+--------------------------+-----------------+
| 0xffff | Reserved | This document |
+--------+--------------------------+-----------------+
¶
Unassigned code points are available for assignment via the "IETF Review" process, as per [RFC8126]. For a new registration request to be accepted, its main purpose MUST be to carry an identifier. The aforementioned identifier MUST be the centerpiece of the new context.¶
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 security considerations for the Context-Data field of the Identifier with Context Option, which varies based on the Context-ID. These custom data structures will have security considerations in their own documents that define the new formats.¶