ISO 4891:2024

International
Standard
ISO 4891
First edition
Ships and marine technology —
2024-11
Interoperability of smart
applications for ships
Navires et technologie maritime — Interopérabilité des
applications intelligentes pour les navires
Reference number
© ISO 2024
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Published in Switzerland
ii
Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 4
5 Smart application network . 5
5.1 Overview .5
5.2 4891-components .8
5.2.1 General .8
5.2.2 4891-message broker .9
5.2.3 4891-service discovery.9
5.2.4 4891-unit registry .10
5.2.5 4891-units .10
5.3 4891-messages .11
5.3.1 General .11
5.3.2 Message structure.11
5.3.3 Header values . 12
5.3.4 Data part encoding . 13
5.3.5 Message type .14
5.3.6 Standard message types .14
5.4 Handling of outdated messages . 15
5.5 Direct messaging . 15
5.6 Message relaying . 15
5.7 Trust and encryption . 15
6 Compatibility implementation .16
6.1 General .16
6.2 JSON-encoding for value types .16
6.2.1 General .16
6.2.2 Common types .16
6.2.3 Dictionary type .17
6.2.4 Message type .18
6.3 HTTP-APIs .21
6.3.1 General .21
6.3.2 HTTP-requests .21
6.3.3 HTTP-request query parameters .21
6.3.4 HTTP-responses. 22
6.3.5 HTTP-error responses . 23
6.3.6 4891-unit authentication . 23
6.4 UDP broadcasts . 26
6.4.1 Sending UDP broadcasts. 26
6.4.2 Listening to UDP broadcasts .27
6.5 4891-message broker . 28
6.5.1 General . 28
6.5.2 Client authentication. 28
6.5.3 Connecting to MQTT-server . 28
6.5.4 Message encoding . 28
6.5.5 Publishing a 4891-message via MQTT . 28
6.5.6 Subscribe to 4891-messages via MQTT . 29
6.6 4891-service discovery . 30
6.6.1 General . 30
6.6.2 Service connectors .31
6.6.3 Service discovery API clients .32

iii
6.6.4 Service discovery API server .32
6.6.5 Service discovery API discovery packet . 33
6.6.6 Service discovery API examples . 33
6.7 4891-unit registry . 34
6.7.1 General . 34
6.7.2 Tracking of unit information . 35
6.7.3 Unit registry API clients . 35
6.7.4 Unit registry API server . 35
6.7.5 Unit registry API examples . 38
6.8 4891-unit . 40
6.9 Direct messaging API .41
6.9.1 General .41
6.9.2 Direct messaging API clients .41
6.9.3 Direct messaging API server.42
6.9.4 Direct messaging API discovery packet .43
6.9.5 Direct messaging API examples .43
6.10 Trust
...