Internet DRAFT - draft-ietf-intarea-schc-ip-protocol-number
draft-ietf-intarea-schc-ip-protocol-number
INTAREA R. Moskowitz
Internet-Draft HTT Consulting
Intended status: Standards Track S. Card
Expires: 9 April 2023 A. Wiethuechter
AX Enterprize, LLC
6 October 2022
Internet Protocol Number for SCHC
draft-ietf-intarea-schc-ip-protocol-number-00
Abstract
This document requests an Internet Protocol Number assignment for
SCHC so that SCHC can be used for IP independent SCHC of other
transports such as UDP and ESP.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Basic use case for SCHC as an Internet Protocol Number . 3
2. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Terminology . . . . . . . . . . . . . . . . 3
3. Internet Protocol Number for SCHC . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4.1. IANA Internet Protocol Number Registry Update . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
LPWAN Static Context Header Compression (SCHC) Architecture
[lpwan-architecture] originally envisioned SCHC used at the Network
layer, encompassing IP and Transport, by the network provider. Then
SCHC would be used by the application; this would include any
security envelope.
This approach brakes down when dealing with Diet ESP [diet-esp].
When Next Header is ESP, it is challenging for the ESP process to
determine if an incoming ESP payload is regular ESP [RFC4303] or a
diet ESP payload. Careful allocation of the incoming SPI
[ikev2-diet-esp] can mitigate this and have an implicit SCHC header,
but it is not sound protocol design. If the Next Header in the IP
header were SCHC, not ESP, a clear segregation of incoming traffic is
directly supportable.
Additionally, SCHC can then be the Next Header within the ESP header
with 'regular' SCHC rules for processing this content. This approach
will greatly simplify [diet-esp].
DTLS 1.3 [RFC9147] adds further complications. DTLS 1.3 headers
themselves are typically already very compressed and SCHC would not
provide much value. But the UDP header in front of DTLS would
benefit of a separate compression from the IP Header compression.
Where it is possible with ESP's SPI to mitigate inbound packet
processing challenges implicit SCHC would generate, DTLS header does
not safely even provide this and a SCHC IP number is necessary to
separate traffic.
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1.1. Basic use case for SCHC as an Internet Protocol Number
A mobile node, or network, may use different links over a period of
time. In some cases the node has the multiple interfaces and, in
theory, could tune the compression to each interface. In other
cases, it is the whole network that is mobile and individual nodes
have no "knowledge" of which link with what characteristics is
actively handling the traffic. In either case, the node
administrator is aware that some links are constrained and use of
SCHC compression is highly recommended.
One example is an UA that uses different links over the duration of
an operation (i.e. flight).
* Operation starts using Veriport's WiFi service.
* On gaining altitude, UA transitions to a Cellular service.
* On gaining more altitude, UA transitions to a constrained 700MHz
UHF service.
* On approach to destination vertiport, link transition is reversed.
The UA could use SCHC compression only on the UHF link, but this may
complicate the implementation.
A more complex example is an Unmanned Cargo Aircraft that has
multiple avionics systems, all Ethernet connected to an onboard
router that has the multiple interfaces. Here the nodes each manage
their own secure path to their ground-based server, but have no
knowledge of which link is in use to intelligently use compression.
2. Terms and Definitions
2.1. Requirements Terminology
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. Internet Protocol Number for SCHC
SCHC as the IP payload SHOULD be indicated in the IPv4 "Protocol"
field or the IPv6 "Next Header" field with a value of TBD1
(recommended: 145) as shown below:
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+=========+=========+================+================+===========+
| Decimal | Keyword | Protocol | IPv6 Extension | Reference |
| | | | Header | |
+=========+=========+================+================+===========+
| TBD1 | SCHC | Static Context | | This RFC |
| (145) | | Header | | |
| | | Compression | | |
+---------+---------+----------------+----------------+-----------+
Table 1: Internet Protocol Numbers
The SCHC compressed header with payload is shown below. The size of
the SCHC RuleID is variable as described in [RFC8724]. An
implementation should have a table of source IP address and RuleID
size. The addresses should be represented in prefix format to allow
for groups of addresses having the same RuleID size.
|------- Compressed Header -------|
+---------------------------------+--------------------+
| RuleID | Compression Residue | Payload |
+---------------------------------+--------------------+
Figure 1: SCHC Packet
The RuleID may be statically configured per [RFC8724], or may be
negotiated within a protocol as in IKE [ikev2-diet-esp].
4. IANA Considerations
4.1. IANA Internet Protocol Number Registry Update
This document requests IANA to make the following change to the
"Assigned Internet Protocol Numbers" [IANA-IPN] registry:
Internet Protocol Number:
This document defines the new Internet Protocol Number value TBD1
(suggested: 145) (Section 3) in the "Assigned Internet Protocol
Numbers" registry.
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+=========+=========+================+================+===========+
| Decimal | Keyword | Protocol | IPv6 Extension | Reference |
| | | | Header | |
+=========+=========+================+================+===========+
| TBD1 | SCHC | Static Context | | This RFC |
| (145) | | Header | | |
| | | Compression | | |
+---------+---------+----------------+----------------+-----------+
Table 2
5. Security Considerations
TBD
6. References
6.1. 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/info/rfc2119>.
[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/info/rfc8174>.
6.2. Informative References
[diet-esp] Migault, D., Guggemos, T., Bormann, C., and D. Schinazi,
"ESP Header Compression and Diet-ESP", Work in Progress,
Internet-Draft, draft-mglt-ipsecme-diet-esp-08, 13 May
2022, <https://datatracker.ietf.org/doc/html/draft-mglt-
ipsecme-diet-esp-08>.
[IANA-IPN] IANA, "Assigned Internet Protocol Numbers",
<https://www.iana.org/assignments/protocol-numbers/
protocol-numbers.xhtml>.
[ikev2-diet-esp]
Migault, D., Guggemos, T., and D. Schinazi, "Internet Key
Exchange version 2 (IKEv2) extension for the ESP Header
Compression (EHC) Strategy", Work in Progress, Internet-
Draft, draft-mglt-ipsecme-ikev2-diet-esp-extension-02, 13
May 2022, <https://datatracker.ietf.org/doc/html/draft-
mglt-ipsecme-ikev2-diet-esp-extension-02>.
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[lpwan-architecture]
Pelov, A., Thubert, P., and A. Minaburo, "LPWAN Static
Context Header Compression (SCHC) Architecture", Work in
Progress, Internet-Draft, draft-ietf-lpwan-architecture-
02, 30 June 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-lpwan-architecture-02>.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, DOI 10.17487/RFC4303, December 2005,
<https://www.rfc-editor.org/info/rfc4303>.
[RFC8724] Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and JC.
Zuniga, "SCHC: Generic Framework for Static Context Header
Compression and Fragmentation", RFC 8724,
DOI 10.17487/RFC8724, April 2020,
<https://www.rfc-editor.org/info/rfc8724>.
[RFC9147] Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
<https://www.rfc-editor.org/info/rfc9147>.
Acknowledgments
Discussions with Pascal Thubert, lpwan co-chair, helped develop this
approach of using SCHC E2E below the current Transport Layers.
Authors' Addresses
Robert Moskowitz
HTT Consulting
Oak Park, MI 48237
United States of America
Email: rgm@labs.htt-consult.com
Stuart W. Card
AX Enterprize, LLC
4947 Commercial Drive
Yorkville, NY 13495
United States of America
Email: stu.card@axenterprize.com
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Adam Wiethuechter
AX Enterprize, LLC
4947 Commercial Drive
Yorkville, NY 13495
United States of America
Email: adam.wiethuechter@axenterprize.com
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