Internet DRAFT - draft-iurman-6man-carry-identifier
draft-iurman-6man-carry-identifier
IPv6 Maintenance J. Iurman
Internet-Draft ULiege
Intended status: Standards Track 8 February 2023
Expires: 12 August 2023
Carrying an Identifier in IPv6 packets
draft-iurman-6man-carry-identifier-00
Abstract
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.
About This Document
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/.
Discussion of this document takes place on the IPv6 Maintenance
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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.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Solution 1: Generic Identifier . . . . . . . . . . . . . . . 3
3.1. Pros and Cons . . . . . . . . . . . . . . . . . . . . . . 4
4. Solution 2: Identifier with Context . . . . . . . . . . . . . 4
4.1. Pros and Cons . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5.1. Generic Identifier (Solution 1) . . . . . . . . . . . . . 5
5.2. Identifier with Context (Solution 2) . . . . . . . . . . 5
5.2.1. Context-ID . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 7
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
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.
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. Solution 1: Generic Identifier
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:
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* Option Type: 8-bit option type as defined in Section 5.1.
* Opt Data Len: 8-bit unsigned integer. Length of the Identifier
field, in octets.
* Identifier: variable length field representing the carried
identifier.
3.1. Pros and Cons
(+) 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.
4. Solution 2: Identifier with Context
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:
* Option Type: 8-bit option type as defined in Section 5.2.
* Opt Data Len: 8-bit unsigned integer. Length of this option, in
octets, not including the first 2 octets.
* Context-ID: 16-bit field as defined in Section 5.2.1.
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* Reserved: 16-bit field MUST be set to zero upon transmission and
ignored upon reception.
* Context-Data: variable length field representing a data structure
which depends on the Context-ID field.
4.1. Pros and Cons
(+) Allows for a context.
(+) Allows for multiple identifiers.
(+) Allows for additional fields.
(+) IETF review process for new Context-ID code points.
(-) Not hardware friendly.
5. IANA Considerations
5.1. Generic Identifier (Solution 1)
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]
5.2. Identifier with Context (Solution 2)
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.
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5.2.1. Context-ID
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:
* Code point: requested code point for the new Context-ID.
* Description: name of the new Context-ID.
* Reference: reference to the document that defines the new Context-
ID.
6. 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 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.
7. References
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7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/rfc/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/rfc/rfc8200>.
[RFC8250] Elkins, N., Hamilton, R., and M. Ackermann, "IPv6
Performance and Diagnostic Metrics (PDM) Destination
Option", RFC 8250, DOI 10.17487/RFC8250, September 2017,
<https://www.rfc-editor.org/rfc/rfc8250>.
7.2. Informative References
[I-D.draft-ietf-6man-enhanced-vpn-vtn-id]
Dong, J., Li, Z., Xie, C., Ma, C., and G. S. Mishra,
"Carrying Virtual Transport Network (VTN) Information in
IPv6 Extension Header", Work in Progress, Internet-Draft,
draft-ietf-6man-enhanced-vpn-vtn-id-02, 24 October 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-6man-
enhanced-vpn-vtn-id-02>.
[I-D.draft-li-6man-topology-id]
Li, Z., Hu, Z., and J. Dong, "Topology Identifier in IPv6
Extension Header", Work in Progress, Internet-Draft,
draft-li-6man-topology-id-00, 20 March 2022,
<https://datatracker.ietf.org/doc/html/draft-li-6man-
topology-id-00>.
Acknowledgments
Author's Address
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Justin Iurman
ULiege
Institut Montefiore B28
Allée de la Découverte 10
4000 Liège
Belgium
Email: justin.iurman@uliege.be
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