Internet DRAFT - draft-templin-intarea-parcels
draft-templin-intarea-parcels
Network Working Group F. L. Templin, Ed.
Internet-Draft Boeing Research & Technology
Intended status: Standards Track 12 February 2024
Expires: 15 August 2024
IPv4 Parcels and Advanced Jumbos (AJs)
draft-templin-intarea-parcels-99
Abstract
IPv6 Parcels and Advanced Jumbos (AJs) present new data packaging
constructs and a new link model for Internetworking. As is often the
case, technologies developed in the IPv6 space can also be applied in
IPv4 and vice-versa. This document presents the adaptations
necessary to support Parcels and AJs in IPv4.
Status of This Memo
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This Internet-Draft will expire on 15 August 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 2
3. IPv4 Parcels and Advanced Jumbos (AJs) . . . . . . . . . . . 3
3.1. IPv4 Total Length . . . . . . . . . . . . . . . . . . . . 3
3.2. IPv4 Time To Live (TTL) . . . . . . . . . . . . . . . . . 3
3.3. IPv4 Parcel/Jumbo Payload Length . . . . . . . . . . . . 4
3.4. IPv4-Compatible IPv6 Addresses . . . . . . . . . . . . . 4
3.5. IPv4 Parcel Packetization/Restoration . . . . . . . . . . 4
3.6. Parcel Probing . . . . . . . . . . . . . . . . . . . . . 4
3.7. Parcel/Jumbo Replys . . . . . . . . . . . . . . . . . . . 5
3.8. Advanced Jumbos (AJs) . . . . . . . . . . . . . . . . . . 5
3.9. Jumbo-in-Jumbo Encapsulation . . . . . . . . . . . . . . 5
3.10. Integrity . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Implementation Status . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
IPv6 Parcels and Advanced Jumbos (AJs) [I-D.templin-6man-parcels]
present new data packaging constructs and a new link model for
Internetworking. As is often the case, technologies developed in the
IPv6 space [RFC8200] can also be applied in IPv4 [RFC0791] and vice-
versa. This document presents the differences that need to be
addressed to adapt IPv6 Parcels and AJs to IPv4.
All aspects of IPv6 Parcels and AJs, including the use of IPv6
extension headers and control messaging, apply also to IPv4. Only
differences in the IP header format and some control option
encapsulations need to be accounted for as discussed below. This
document therefore specifies IPv4 parcels and AJs.
2. Requirements
IPv4 parcels and AJs observe all requirements established for IPv6
[I-D.templin-6man-parcels] including the use of IPv6 Hop-by-Hop
Options headers. This means that nodes that recognize IPv4 parcels/
AJs MUST recognize and correctly process IP protocol 0 (Hop-by-Hop)
extension headers the same as for IPv6 when they occur in an
extension header chain following the IPv4 header but before the upper
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layer payload.
When an IPv4 router or destination end system processes a parcel/AJ
probe for which the IPv4 Protocol field encodes an unrecognized value
(such as 0 for Hop-by-Hop Options), it drops the probe and returns an
ICMPv4 "Destination Unreachable - Protocol Unreachable" message
[RFC0792]. The source should regard any such messages as an advisory
indication that OMNI protocol UDP encapsulation may be necessary in
future probes.
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. IPv4 Parcels and Advanced Jumbos (AJs)
All aspects of [I-D.templin-6man-parcels] are imported as normative
specifications for IPv4 parcels and AJs, with the exception of the
following differences:
3.1. IPv4 Total Length
The IPv6 header includes a "Payload Length" field defined as the:
"Length of the IPv6 payload, i.e., the rest of the packet following
this IPv6 header, in octets". The IPv4 header instead includes a
"Total Length" field defined as: "the length of the datagram,
measured in octets, including internet header and data".
IPv6 parcels/AJs always set the Payload Length field to 0; thus, a
node that does not understand the parcel/AJ format may truncate the
message and send only the IPv6 header forward.
IPv4 parcels/AJs instead always set the Total Length to the length of
the IPv4 header to ensure the same truncation behavior.
3.2. IPv4 Time To Live (TTL)
The IPv4 "Time To Live (TTL)" and IPv6 "Hop Limit" values are treated
in exactly the same way in both protocol versions. In particular,
the source sets the TTL/Hop Limit to an initial value and each router
in the path to the destination decrements the TTL/Hop Limit by 1 when
it forwards a parcel/AJ/probe. (Note that this represents a parcel/
AJ-specific requirement for IPv4 routers, since [RFC1812] permits
routers to decrement TTL by values other than 1.)
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3.3. IPv4 Parcel/Jumbo Payload Length
The same as for IPv6, the Parcel Payload Length field in the Parcel
Payload Option and the Jumbo Payload Length field in the Jumbo
Payload Option of IPv4 parcels/AJs encode the length of the IPv6
extension headers plus the length of the {TCP,UDP} header plus the
combined length of all concatenated segments with their per-segment
headers/trailers.
Therefore, the length of the IPv4 header itself is not included in
the Parcel/Jumbo Payload Length field the same as for IPv6. The IPv4
header length for IPv4 parcels and AJs is instead available in both
the IPv4 Total Length and Internet Header Length (IHL) fields.
3.4. IPv4-Compatible IPv6 Addresses
Whenever an IPv4 address needs to be coded in an IPv6 address field,
the address is coded as an IPv4-compatible IPv6 address as specified
in [RFC4291].
3.5. IPv4 Parcel Packetization/Restoration
When a node performs packetization on a {TCP,UDP}/IPv4 parcel, it
inserts a Parcel Parameters {TCP,UDP} option the same as for IPv6
[I-D.templin-6man-parcels].
The IPv4 destination then performs restoration by gathering up IPv4
packets that arrive with the same upper layer 5-tuple and with Parcel
Parameters information including the same Identification. The Parcel
Parameters Index then determines the ordinal position of each packet
segment to be concatenated into the restoration buffer, i.e., the
same as for IPv6. (Note: if the IPv4 destination does not recognize
the {TCP,UDP} Parcel Parameters option, it simply processes the
packet as a singleton IPv4 packet. This would result in correct
behavior, but with Generic Receive Offload (GRO) disabled.)
3.6. Parcel Probing
When an IPv4 router or destination receives an intact parcel probe,
it processes the probe the same as specified for IPv6
[I-D.templin-6man-parcels].
When an IPv4 router forwards the parcel probe, it MUST decrement the
TTL by exactly 1 the same as specified for the IPv6 Hop Limit.
When an IPv4 destination receives a parcel probe, it should return a
Parcel Parameters option in any {TCP,UDP}/IPv4 packet to be returned
to the source the same as for IPv6.
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When the IPv4 source receives a {TCP,UDP} packet that includes a
Parcel Parameters option it matches the Identification value with its
recently-transmitted probes. If there is a match, the source accepts
the MTU and Parcel Limit values found in the Parcel Parameters
option.
The same as for IPv6, if the source or destination is located outside
of a controlled environment / limited domain [RFC8799] the source
should send probes including the IPv4 header followed by an OMNI UDP
encapsulation header followed by the Hop-by-Hop Options header and
finally followed by the {TCP,UDP} header plus protocol data.
3.7. Parcel/Jumbo Replys
When an IPv4 router returns a Parcel/Jumbo Reply, it prepares the
message in exactly the same way as for IPv6 (i.e., including the
ICMPv6 message body and optional Encapsulating Security Payload (ESP)
encapsulation) then wraps the message in UDP/IPv4 headers for
transmission to the source according to the OMNI protocol
specification.
3.8. Advanced Jumbos (AJs)
All aspects of IPv4 Advanced Jumbos (AJ) are processed the same as
for IPv6 AJs.
3.9. Jumbo-in-Jumbo Encapsulation
Original IPv4 parcels/AJs can follow the "e(X)treme" forwarding paths
across successive OMNI links in the path using "jumbo-in-jumbo"
encapsulation the same as for IPv6. The OMNI link ingress
encapsulates each IPv4 parcel/AJ in an OMNI IPv6 header plus any
outer L2 encapsulations which may include an IPv4 header with an
Advanced Jumbo option Hop-By-Hop extension header. All aspects of
this "jumbo-in-jumbo" encapsulation are the same as for IPv6.
3.10. Integrity
To support the IPv4 parcel/AJ header checksum calculation, the
network layer uses modified versions of the {TCP,UDP}/IPv4 pseudo-
header found in [RFC9293]. Note that while the contents of the two
IP protocol version-specific pseudo-headers beyond the address fields
are the same, the order in which the contents are arranged differs
and must be honored according to the specific IP protocol version.
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The IPv6 pseudo-header is found in [I-D.templin-6man-parcels], while
the IPv4 pseudo-header is shown in Figure 1. The similarities
between the two pseudo-headers allows for maximal reuse of widely
deployed code while ensuring interoperability.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Source Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Destination Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| zero | Next Header | Segment Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index |C|S|D|X| Parcel Payload Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: {TCP,UDP}/IPv4 Parcel/AJ Pseudo-Header Format
Note: The same as for IPv6, the "Index/C/S/D/X" and Parcel Payload
Length fields in the IPv4 parcel pseudo-header are replaced by the
single 4-octet Jumbo Payload Length field in the IPv4 AJ pseudo-
header.
4. Implementation Status
An early prototype of UDP/IPv4 parcels (draft version -15) has been
implemented relative to the linux-5.10.67 kernel and ION-DTN ion-
open-source-4.1.0 source distributions. Patch distribution found at:
"https://github.com/fltemplin/ip-parcels.git".
5. IANA Considerations
This document does not include any IANA instructions.
6. Security Considerations
Security Considerations are the same as for IPv6 as found in
[I-D.templin-6man-parcels].
7. Acknowledgements
This work was inspired by ongoing AERO/OMNI/DTN investigations. The
concepts were further motivated through discussions with colleagues.
Honoring life, liberty and the pursuit of happiness.
8. References
8.1. Normative References
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[I-D.templin-6man-parcels]
Templin, F., "IPv6 Parcels and Advanced Jumbos (AJs)",
Work in Progress, Internet-Draft, draft-templin-6man-
parcels-18, 26 January 2024,
<https://datatracker.ietf.org/doc/html/draft-templin-6man-
parcels-18>.
[I-D.templin-intarea-omni]
Templin, F., "Transmission of IP Packets over Overlay
Multilink Network (OMNI) Interfaces", Work in Progress,
Internet-Draft, draft-templin-intarea-omni-64, 26 January
2024, <https://datatracker.ietf.org/doc/html/draft-
templin-intarea-omni-64>.
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/info/rfc768>.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, DOI 10.17487/RFC0792, September 1981,
<https://www.rfc-editor.org/info/rfc792>.
[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>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/info/rfc4291>.
[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>.
[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/info/rfc8200>.
[RFC9293] Eddy, W., Ed., "Transmission Control Protocol (TCP)",
STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
<https://www.rfc-editor.org/info/rfc9293>.
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8.2. Informative References
[RFC1812] Baker, F., Ed., "Requirements for IP Version 4 Routers",
RFC 1812, DOI 10.17487/RFC1812, June 1995,
<https://www.rfc-editor.org/info/rfc1812>.
[RFC8799] Carpenter, B. and B. Liu, "Limited Domains and Internet
Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
<https://www.rfc-editor.org/info/rfc8799>.
Appendix A. Change Log
<< RFC Editor - remove prior to publication >>
Changes from earlier versions:
* Submit for review.
Author's Address
Fred L. Templin (editor)
Boeing Research & Technology
P.O. Box 3707
Seattle, WA 98124
United States of America
Email: fltemplin@acm.org
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