Modem-Side Configuration (Remote Edge)

MAPS can integrate directly with ST2100 / IDP / OGx modems via serial.
This setup is best suited for remote or disconnected deployments where the modem is the only uplink.

On the modem side, MAPS primarily acts as a link endpoint: it bridges local MAPS namespaces to a remote satellite transport.

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Modem-Side Message Routing Overview

On the modem side, MAPS handles two distinct classes of traffic:

Traffic Type	Description
Raw satellite messages	SIN/MIN-addressed payloads sent to or received from the modem without MAPS application framing
MAPS messages	Application-level payloads routed via MAPS namespaces, schemas, and selectors

Routing is determined by configuration, not payload inspection:

• Raw messages use modemRawRequest and modemRawResponse
• MAPS messages use links (namespace integrations)

This separation is intentional and enforced.

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Raw Satellite Message Topics (Non-MAPS Traffic)

Raw satellite messages bypass MAPS namespace routing and schema handling.

modemRawRequest

Defines the topic template where inbound raw satellite messages are published after reception from the modem.

Default

/incoming/{sin}/{min}

Behaviour

• Applies to all non-MAPS messages
• {sin} and {min} are extracted from the modem frame
• Payload is published as raw byte[]
• No schema, selector, or namespace processing is applied

Typical uses include modem control responses, GNSS data, and provider-specific payloads.

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modemRawResponse

Defines the topic MAPS monitors for outbound raw satellite messages to send directly to the modem.

Default

/outbound

Behaviour

• Any message published here is sent directly to the modem
• No MAPS packaging, schema, or selector logic is applied
• SIN/MIN must be supplied by the publishing client

This is a direct pipe to the modem.

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MAPS Message Handling via Links (Application Traffic)

MAPS application messages are routed using links, the same integration mechanism used by MAPS servers.

A modem configuration is therefore a specialised link endpoint, not a separate routing system.

MAPS SIN Configuration

All MAPS messages sent via the modem use:

sinNumber (default: 147)

• Applies only to MAPS messages routed via links
• Ignored for raw satellite traffic
• Must be greater than 128

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Links: Namespace-Based Routing

The links section defines how local MAPS namespaces are bridged to remote namespaces over the satellite link.

Each link represents a directional integration.

Link Fields

Field	Description
direction	Message flow direction (push or pull)
local_namespace	Local MAPS namespace to monitor
remote_namespace	Namespace used on the remote side
include_schema	Include schema information with messages
selector	Expression used to filter messages
namespaceFilters	Optional per-sub-namespace filtering rules

Links support the full MAPS selector and schema system.

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Namespace Filters

namespaceFilters allow fine-grained control within a link by applying additional rules to sub-namespaces.

Each filter supports:

Field	Description
namespace	Namespace prefix the filter applies to
selector	Optional condition applied under this namespace
depth	Topic depth under the namespace to evaluate

Evaluation Order

1. The link-level selector is evaluated first.
2. If it passes, matching namespaceFilters are evaluated.
3. Both must evaluate to true for the message to be forwarded.

Use selector: "TRUE" at the link level to delegate all filtering to namespace filters.

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Relationship to Server Integrations

The modem-side links configuration is identical in concept to server-side integrations:

• Same selector language
• Same schema handling
• Same namespace semantics

The only difference is the transport:

• Server integrations route over TCP/REST/messaging protocols
• Modem integrations route over a serial satellite link

This allows modem deployments to behave consistently with central MAPS servers.

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Example Configuration

- name: "ST2100 Modem"
  url: serial://localhost:0/
  protocol: stogi

  initialSetup: ""
  incomingMessagePollInterval: 1
  outgoingMessagePollInterval: 20
  sharedSecret: "This is a shared secret to use"

  modemResponseTimeout: 20000
  locationPollInterval: 60

  maxBufferSize: 4000
  compressionCutoffSize: 128

  modemStatsTopic: "/modem/stats"
  modemRawRequest: "/incoming/{sin}/{min}"
  modemRawResponse: "/outbound"

  links:
    - direction: push
      local_namespace: "/vessel/+/engine/rpm"
      remote_namespace: "/satellite/engine/rpm"
      include_schema: true
      selector: "rpm > 5000"

    - direction: push
      local_namespace: "/sensors/+/temperature"
      remote_namespace: "/satellite/anomalies"
      include_schema: false
      selector: "random_forest(is_anomaly, model_rf.arff, temperature, humidity, pressure) = 1"
      namespaceFilters:
        - namespace: /sensors/mess/
          selector: temperature > 30 OR temperature < 17
          depth: 1
        - namespace: /sensors/engineroom/
          depth: 10

  serial:
    port: ttyusb0
    baudRate: 9600
    dataBits: 8
    stopBits: 1
    parity: n
    flowControl: 0

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Complete Configuration Reference

Base Satellite Fields

Field	Description
incomingMessagePollInterval	Poll interval (seconds) for inbound modem messages
outgoingMessagePollInterval	Flush interval (seconds) for outbound messages
maxBufferSize	Maximum payload size before chunking
compressionCutoffSize	Payload size threshold for compression
messageLifeTimeInMinutes	Message TTL before expiry
sharedSecret	Optional lightweight authentication
sendHighPriorityMessages	Bypass queueing for urgent messages
sinNumber	SIN used for MAPS messages (default 147)

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Modem-Specific Fields

Field	Description
serial	Serial port configuration
modemResponseTimeout	Time to wait for modem responses (ms)
initialSetup	Optional modem initialisation string
locationPollInterval	GNSS/visibility polling interval (seconds)
modemStatsTopic	Topic for publishing modem statistics
modemRawRequest	Inbound topic template for raw satellite messages
modemRawResponse	Outbound topic for raw satellite messages