RFC 9171, "Bundle Protocol Version 7", January 2022

Note: This RFC has been updated by RFC 9713, RFC 9758

Errata ID: 8377
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT, PDF, HTML
Reported By: Ed Birrane
Date Reported: 2025-04-07
Held for Document Update by: Erik Kline
Date Held: 2025-08-11

Section 5.7 says:

If the received bundle is a fragment, the ADU 
Reassembly procedure described in Section 5.9 MUST 
be followed. If this procedure results in reassembly 
of the entire original ADU, processing of the 
fragmentary bundle whose payload has been replaced 
by the reassembled ADU (whether this bundle or a 
previously received fragment) proceeds from Step 2; 

It should say:

If the received bundle is a fragment, the ADU 
Reassembly procedure described in Section 5.9 MUST 
be followed. If this procedure results in reassembly 
of the entire original ADU, 

then the original primary block of the fragmented 
bundle whose ADU has been reassembled must replace 
the primary block of the fragmentary bundle whose
payload has been replaced by the reassembled ADU.

Processing of this fragmentary bundle proceeds 
from Step 2; 

Notes:

When performing bundle fragmentation, the original bundle is never fully reconstituted because the original bundle primary block is never recreated upon reassembly. This means that any extension blocks that require the original bundle primary block to be intact (such as security blocks) cannot verify the reassembled bundle.

A solution to bundle reassembly that allows for the original bundle to be secured and then verified/decrypted upon reassembly needs to be put in place as the text in 9171 currently cannot support this.

--- AD notes ---

RFC 9171 ADU Fragmentation has issues with extension blocks and fragmented bundle size. It requires a thorough and consistent update via a separate document (too large for an erratum).

For more context see:
* https://mailarchive.ietf.org/arch/msg/dtn/2lY2RE_onIXCbO-IAPdylsf819s/
* other discussion ongoing on the mailing list

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