PROTAP — EDIFACT Project Tasks Planning Message (D.21B)

The PROTAP message carries the planning of project tasks between a project owner and a contractor: WBS breakdown, dependencies, milestones, resources, workload and associated costs. It is a vehicle for structured project-plan exchange, rarely used in practice. This page summarises the segment structure as published by UN/CEFACT for directory D.21B.

Purpose

The PROTAP message carries the planning of project tasks between a project owner and a contractor: WBS breakdown, dependencies, milestones, resources, workload and associated costs. It is a vehicle for structured project-plan exchange, rarely used in practice.

This page focuses on the structure published by UN/CEFACT for directory D.21B. The segments listed, their status (M / C), position and repetition factor are extracted from the official file protap_c.htm hosted on service.unece.org.

Segment structure

The PROTAP D.21B message has 51 header entries, 49 detail entries and 2 summary entries (segments and groups combined). Groups are shown in bold and their members are indented by actual nesting depth.

Header

Detail

Summary

Changes vs D.96A

The PROTAP message is not published in directory D.96A. No "D.96A → D.21B" comparison line can therefore be produced — see the block below for details.

This message is not published in directory D.96A: it was introduced into the standard after that release and therefore has no historical baseline for comparison. The first directory indexed on ediverse.io sets the reference; later changes are then documented from one release to the next in subsequent directories.

Structural example

Minimal example of an PROTAP D.21B message with mandatory segments only. The goal is to show the exact version declared in UNH (PROTAP:D:21B:UN) — not to replicate a full business case.

UNB+UNOC:3+5410000000123:14+5410000000456:14+260514:1430+CTRL021001'
UNH+1+PROTAP:D:21B:UN'
BGM+39+PROTAP-2026-0007+9'
DTM+137:20260514:102'
RFF+AGA:PROJ-2026-MIG-ERP'
NAD+BY+5410000000123::9'
NAD+SU+5410000000456::9'
LIN+1+++WBS-1.1:ZZZ'
IMD+F++:::Discovery and assessment workshop'
DTM+264:20260601:102'
DTM+265:20260615:102'
UNT+10+1'
UNZ+1+CTRL021001'

Common errors

• Misaligned UNH tokens — The UNH+...+PROTAP:D:21B:UN token must reflect exactly the directory in use — a mismatch between the UNH release and the release agreed with the partner is rejected by every strict validator.
• Wrong UNT segment count — The value after UNT+ must include UNH and UNT themselves. By far the most common sender-side error, regardless of the directory in use.
• Stale code lists — Between D.96A and D.21B, several code lists received new qualifiers (DTM status, RFF qualifier, NAD codes…). Reusing an older directory’s code tables triggers warnings or even rejections depending on the partner’s strict-conformance mode.

Related messages

Other versions of this message available on ediverse.io: PROTAP D.01B, PROTAP D.10A, PROTAP D.16B, PROTAP D.24A, PROTAP D.99B, PROTAP D.00B, PROTAP D.02B, PROTAP D.05A, PROTAP D.08A, PROTAP D.13B, PROTAP D.18B, PROTAP D.20B.

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