IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) Selective Fragment Recovery
RFC 8931
Document | Type |
RFC - Proposed Standard
(November 2020; No errata)
Updates RFC 4944
|
|
---|---|---|---|
Author | Pascal Thubert | ||
Last updated | 2020-11-23 | ||
Replaces | draft-thubert-6lo-fragment-recovery | ||
Stream | IETF | ||
Formats | plain text html xml pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Carles Gomez | ||
Shepherd write-up | Show (last changed 2019-10-23) | ||
IESG | IESG state | RFC 8931 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Suresh Krishnan | ||
Send notices to | Carles Gomez <carlesgo@entel.upc.edu> | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack | ||
IANA expert review state | Expert Reviews OK | ||
IANA expert review comments | The expert approved the registrations, but wrote, "One slight concern is that it registers not 1 or 2 codes, but 4. However, rfc8025 was created precisely because of this problem, as these registrations are limited to page 0 only." |
Internet Engineering Task Force (IETF) P. Thubert, Ed. Request for Comments: 8931 Cisco Systems Updates: 4944 November 2020 Category: Standards Track ISSN: 2070-1721 IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) Selective Fragment Recovery Abstract This document updates RFC 4944 with a protocol that forwards individual fragments across a route-over mesh and recovers them end to end, with congestion control capabilities to protect the network. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8931. Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction 2. Terminology 2.1. Requirements Language 2.2. Background 2.3. Other Terms 3. Updating RFC 4944 4. Extending RFC 8930 4.1. Slack in the First Fragment 4.2. Gap between Frames 4.3. Congestion Control 4.4. Modifying the First Fragment 5. New Dispatch Types and Headers 5.1. Recoverable Fragment Dispatch Type and Header 5.2. RFRAG Acknowledgment Dispatch Type and Header 6. Fragment Recovery 6.1. Forwarding Fragments 6.1.1. Receiving the First Fragment 6.1.2. Receiving the Next Fragments 6.2. Receiving RFRAG Acknowledgments 6.3. Aborting the Transmission of a Fragmented Packet 6.4. Applying Recoverable Fragmentation along a Diverse Path 7. Management Considerations 7.1. Protocol Parameters 7.2. Observing the Network 8. Security Considerations 9. IANA Considerations 10. References 10.1. Normative References 10.2. Informative References Appendix A. Rationale Appendix B. Requirements Appendix C. Considerations on Congestion Control Acknowledgments Author's Address 1. Introduction In most Low-Power and Lossy Network (LLN) applications, the bulk of the traffic consists of small chunks of data (on the order of a few bytes to a few tens of bytes) at a time. Given that an IEEE Std 802.15.4 [IEEE.802.15.4] frame can carry a payload of 74 bytes or more, fragmentation is usually not required. However, and though this happens only occasionally, a number of mission-critical applications do require the capability to transfer larger chunks of data, for instance, to support the firmware upgrade of the LLN nodes or the extraction of logs from LLN nodes. In the former case, the large chunk of data is transferred to the LLN node, whereas in the latter case, the large chunk flows away from the LLN node. In both cases, the size can be on the order of 10 KB or more, and an end-to-end reliable transport is required. "Transmission of IPv6 Packets over IEEE 802.15.4 Networks" [RFC4944] defines the original IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) datagram fragmentation mechanism for LLNs. One critical issue with this original design is that routing an IPv6 [RFC8200] packet across a route-over mesh requires the reassembly of the packet at each hop. "An Architecture for IPv6 over the TSCH mode of IEEE 802.15.4" [6TiSCH] indicates that this may cause latency along a path and impact critical resources such as memory and battery; to alleviate those undesirable effects, it recommends using a 6LoWPAN Fragment Forwarding (6LFF) technique. "On Forwarding 6LoWPAN Fragments over a Multihop IPv6 Network" [RFC8930] specifies the generic behavior that all 6LFF techniques including this specification follow, and it presents the associated caveats. In particular, the routing information is fully indicated in the first fragment, which is always forwarded first. With thisShow full document text