Interface control document

1. Identification

2. Scope

This document defines the UDP transport and header-level acceptance rules the Open DIS module applies to incoming DIS-7 traffic, and how that traffic maps onto session start/stop and published data. It does not define the DIS-7 PDU format itself - that is IEEE’s published standard, not a VRAI interface - only the subset of the header this module inspects, and what it does with a PDU once accepted.

This module is peer-to-product only: it never transmits a PDU onto the network. It publishes every accepted PDU’s raw bytes unmodified; it does not decode, validate, or otherwise interpret any DIS PDU content beyond the header fields in Section 4.4.

3. Interface inventory

4. IF-CMOPENDIS-01 DIS-7 PDU feed

4.1 Transport and addressing

4.2 Session and connection lifecycle

The receiver is not connection-oriented and has no lifecycle of its own beyond the module’s: it binds when HEAT Capture starts (this module runs continuously, independent of capture sessions - see Overview) and stays bound until HEAT Capture exits. Changing UdpPort, NetworkMode or NetworkGroupAddress tears down and recreates the socket in place, without restarting the module or losing packets sent before the rebuild completes beyond what UDP itself may drop.

A peer needs no handshake or session negotiation with this module; it sends UDP datagrams to the bound port or joined multicast group. This module never acknowledges receipt.

4.3 Authentication

None. Any sender able to reach the bound port or joined multicast group is accepted, subject only to the LocalCaptureOnly filter (4.4).

4.4 Header acceptance rules

Every received datagram is checked before being published; a datagram failing any check is dropped (see error behaviour, 4.7).

This module reads no other part of the DIS-7 header or body.

4.5 Message set

There is no message set beyond “a DIS-7 PDU” - this module treats every accepted datagram identically regardless of PDU type, except for the session-trigger types named in Section 4.6. See PduType for the type enumeration used only for that triggering, not for filtering.

4.6 Session triggering and timing

Received as datagrams arrive; there is no polling. Whether a PDU also starts or stops a capture session depends on StartOnAnyPDU, StartOnSpecificPDU/StartPduTypes, StopOnSpecificPDU/StopPduTypes and StopOnSilence/SilenceThreshold - see Configure. A PDU that triggers a session stop is still published before the module acts on the trigger.

4.7 Error behaviour

5. Data model reference

Output is a HEAT ProtoLib PDU message - a single payload field carrying the DIS-7 datagram’s raw bytes. See HEAT ProtoLib’s message reference. This module populates no other ProtoLib message and decodes no DIS-7 content.

6. Units, frames and conventions

7. Configuration affecting the interface

See Configure for the full settings reference.

8. Compatibility and versioning

Built against HEAT.Capture.ModuleSDK 2.0.5. This module does not identify or negotiate a DIS protocol version with the peer beyond the wide, deliberately permissive version-byte range in 4.4; a peer sending a structurally valid but semantically newer or vendor-extended DIS-7 variant is accepted and republished unmodified, since this module never interprets PDU content.

9. Security considerations

There is no authentication and no transport encryption: any sender reaching the bound port or joined multicast group is accepted (subject only to LocalCaptureOnly), and its datagram becomes recorded data.

This module declares the network.listen capability for udp/3000 specifically. HEAT Capture’s host-side firewall scoping is built from that declaration - changing UdpPort without a matching firewall change moves the listener outside its granted scope. Treat the network this module listens on as the security boundary; do not expose it beyond an isolated simulation network.

10. Conformance

1. Start HEAT Capture with this module enabled. Confirm the module’s debug view reports receiverActive: true and the configured udpPort.
2. Send a well-formed DIS-7 PDU (any type) to the configured port/mode. Confirm receivedPackets and publishedPackets both increment, and lastPduType shows the sent type.
3. With StartOnSpecificPDU enabled and default StartPduTypes, send a Start/Resume PDU. Confirm sessionStarted flips to true.
4. Send a datagram shorter than 12 bytes. Confirm droppedPackets increments and publishedPackets does not.
5. Enable LocalCaptureOnly and send from a non-local sender. Confirm droppedPackets increments with no corresponding warning in the log.

11. Revision history

HEAT Capture team. Last updated 2 October 2026.