Cloud Protocol Reference

Introduction

This page provides the complete protocol reference for the AosEdge Unit-Cloud communication protocol version 7. The protocol defines how Units exchange structured JSON messages with the AosCloud backend over a persistent WebSocket connection secured by mTLS.

The protocol is defined in code rather than a standalone specification document. The authoritative source is the Python Pydantic models at cloud-common/cloud_common/protocols/unit/v7/ (cloud side) and the C++ serialization code at aos_core_cpp/src/common/cloudprotocol/ (Unit side). This reference documents the protocol as implemented in those sources.

Protocol Overview

Property	Value
Protocol version	7
Transport	WebSocket (binary frames)
Serialization	JSON
Endpoint	/ws/v7/
Authentication	Mutual TLS (mTLS) with online certificate
Service discovery	HTTP POST to /sd/v7/

Message Envelope

Every message exchanged over the WebSocket uses a two-part envelope structure: a header and a data payload.

{
  "header": {
    "version": 7,
    "systemId": "unit-abc-123",
    "createdAt": "2025-01-15T10:30:00Z",
    "txn": "550e8400-e29b-41d4-a716-446655440000"
  },
  "data": {
    "messageType": "unitStatus",
    ...
  }
}

Header Fields

Field	Type	Required	Description
version	integer	Yes	Protocol version. Always 7 for this protocol version.
systemId	string	Yes	Unique identifier of the Unit sending or receiving the message.
createdAt	string (ISO 8601)	Yes	Timestamp when the message was created.
txn	string (UUID)	Yes	Transaction ID used for acknowledgment correlation and tracing.

Data Payload

The data object contains the message body. The messageType field acts as a discriminator that determines the schema of the remaining fields. An optional correlationId field links request/response pairs.

Field	Type	Required	Description
messageType	string	Yes	Discriminator identifying the message type.
correlationId	string	No	Links a response to its originating request.

Acknowledgment Protocol

Every message sent over the WebSocket must be acknowledged by the receiver:

• ack — confirms the message was received and accepted for processing
• nack — indicates the message could not be processed; includes a retryAfter hint

ack

Direction: Both (Unit→Cloud and Cloud→Unit)

{
  "messageType": "ack",
  "correlationId": "<txn of acknowledged message>"
}

nack

Direction: Cloud → Unit

{
  "messageType": "nack",
  "correlationId": "<txn of rejected message>",
  "retryAfter": 500
}

Field	Type	Description
retryAfter	integer	Suggested retry delay in milliseconds. Default: 500.

The CM implementation retries unacknowledged messages up to 3 times. If no acknowledgment is received within the timeout period, the connection is considered broken and reconnection is initiated.

Common Data Structures

Several data structures are shared across multiple message types.

AosIdentity

A flexible identifier used for nodes, items, subjects, and other objects throughout the protocol.

Field	Type	Required	Description
id	string (UUID)	No	Unique UUID identifier.
type	string	No	Object type (e.g., AosService, AosComponent).
codename	string	No	Human-readable codename.
title	string	No	Display title.
description	string	No	Description text.
urn	string	No	Globally unique URN.

ErrorInfo

Error details attached to status reports when an operation fails.

Field	Type	Required	Description
code	integer	Yes	Error code.
message	string	Yes	Human-readable error description.

Desired Status (Cloud → Unit)

The desiredStatus message is the primary control message from cloud to Unit. It declares the target state — which Deployable Items should be installed, which service instances should be running, and the desired node states.

Message type: desiredStatus

{
  "messageType": "desiredStatus",
  "nodes": [...],
  "unitConfig": {...},
  "items": [...],
  "instances": [...],
  "subjects": [...],
  "certificates": [...],
  "certificateChains": [...]
}

Top-Level Fields

Field	Type	Required	Description
nodes	array of NodeDesiredState	No	Desired state for each node (provisioned or paused).
unitConfig	UnitConfig	No	Unit configuration to apply.
items	array of DesiredUpdateItemInfo	No	Deployable Items that should be installed.
instances	array of DesiredInstanceInfo	No	Service instances that should be running.
subjects	array of AosSubject	No	Subject definitions used for access control.
certificates	array of CertificateInfo	No	Certificates for Verification of Deployable Items.
certificateChains	array of CertificateChainInfo	No	Certificate chains for signature Verification.

NodeDesiredState

Field	Type	Description
item	AosIdentity	Node identifier.
state	string	Desired state: provisioned or paused.

DesiredUpdateItemInfo

Describes a Deployable Item that should be present on the Unit.

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
version	string (SemVer)	Target version.
owner	AosIdentity	Owner identity (OEM or service provider).
indexDigest	string	Digest of the OCI index.json for the item.

DesiredInstanceInfo

Describes a service instance that should be running.

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject (tenant) for the instance.
priority	integer (0–999999)	Scheduling priority. Default: 0.
numInstances	integer (≥0)	Number of instances to run. Default: 1.
labels	array of string	Optional labels for placement constraints.

UnitConfig

Delivered as part of desiredStatus to configure node-level parameters.

Field	Type	Description
version	string	Configuration version (auto-incremented).
formatVersion	string	Format version of the configuration structure.
nodes	array of NodeConfig	Per-node configuration entries.

NodeConfig

Field	Type	Description
nodeGroupSubject	AosIdentity	Node group subject (identifies the node type).
node	AosIdentity	Optional specific node identifier.
alertRules	AlertRules	Threshold rules for CPU, RAM, disk, and network alerts.
resourceRatios	ResourceRatiosInfo	Default resource allocation ratios (cpu, ram, storage, state as percentages).
labels	array of string	Labels for this node.
priority	integer (≥0)	Node priority for service placement.

Unit Status (Unit → Cloud)

The unitStatus message reports the current state of the Unit — its nodes, installed Deployable Items, running instances, and configuration status.

Message type: unitStatus

{
  "messageType": "unitStatus",
  "isDeltaInfo": false,
  "unitConfig": [...],
  "nodes": [...],
  "items": [...],
  "instances": [...],
  "subjects": [...]
}

Top-Level Fields

Field	Type	Required	Description
isDeltaInfo	boolean	No	If true, this is a delta update (only changed fields). If false or absent, this is a full status report.
unitConfig	array of UnitConfigStatus	No	Status of the installed unit configuration.
nodes	array of UnitNodeInfo	No	Information about all nodes attached to the Unit.
items	array of UpdateItemInfo	No	Status of installed Deployable Items.
instances	array of InstancesInfo	No	Status of running service instances.
subjects	array of AosIdentity	No	Active subjects on the Unit.

UnitConfigStatus

Field	Type	Description
version	string	Installed configuration version.
state	string	State: absent, installed, or failed.
errorInfo	ErrorInfo	Error details if state is failed.

UnitNodeInfo

Reports comprehensive information about a node attached to the Unit.

Field	Type	Description
identity	AosIdentity	Node identifier.
nodeGroupSubject	AosIdentity	Node group subject (node type).
maxDmips	integer	Maximum DMIPS capacity.
physicalRam	integer	Physical RAM in bytes.
totalRam	integer	Total RAM (physical + swap) in bytes.
osInfo	OsInfo	Operating system information (os, version, features).
cpus	array of NodeCPUInfo	CPU details (model, cores, threads, architecture).
attrs	object	Key-value attributes (e.g., dynamic, cloud_connection).
partitions	array of NodePartitionInfo	Disk partition information (name, types, totalSize).
runtimes	array of RuntimeInfo	Supported container runtimes.
resources	array of ResourceInfo	Available shared resources.
isConnected	boolean	Whether the node is connected to the main node.
state	string	Node state: unprovisioned, provisioned, error, or paused.
errorInfo	ErrorInfo	Error details if state is error.

UpdateItemInfo

Reports the status of an installed Deployable Item.

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
version	string (SemVer)	Installed version.
state	string	Item state (see below).
errorInfo	ErrorInfo	Error details if state is failed.

Deployable Item states: unknown, downloading, pending, installing, installed, removing, removed, failed

InstancesInfo

Reports the status of running service instances for a specific Deployable Item.

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject (tenant) identifier.
version	string (SemVer)	Item version.
instances	array of InstanceInfo	Per-instance status.

InstanceInfo

Field	Type	Description
node	AosIdentity	Node where the instance runs.
runtime	AosIdentity	Runtime used for the instance.
instance	integer	Instance number (starting from 0).
stateChecksum	string (Base64)	SHA-256 checksum of the instance state.
state	string	Instance state: activating, active, inactive, or failed.
errorInfo	ErrorInfo	Error details if state is failed.

Alerts (Unit → Cloud)

The alerts message carries a batch of alert items from the Unit to the cloud. Alerts are discriminated by a tag field.

Message type: alerts

{
  "messageType": "alerts",
  "items": [
    { "tag": "systemAlert", ... },
    { "tag": "coreAlert", ... }
  ]
}

Alert Types

Tag	Description
systemAlert	System-level error on a node.
coreAlert	Error in an AosCore component (CM, SM, IAM, MP).
deviceAllocateAlert	Resource allocation failure for a service instance.
systemQuotaAlert	System resource threshold exceeded on a node.
instanceQuotaAlert	Service instance resource threshold exceeded.
downloadProgressAlert	Download progress or failure notification.
updateItemInstanceAlert	Service instance lifecycle event.

systemAlert

Field	Type	Description
tag	"systemAlert"	Alert type discriminator.
timestamp	string (ISO 8601)	When the alert was triggered.
node	AosIdentity	Node where the alert occurred.
message	string	Error description.

coreAlert

Field	Type	Description
tag	"coreAlert"	Alert type discriminator.
timestamp	string (ISO 8601)	When the alert was triggered.
node	AosIdentity	Node where the alert occurred.
coreComponent	string	Component ID (e.g., cm, sm, iam).
message	string	Error description.

systemQuotaAlert

Field	Type	Description
tag	"systemQuotaAlert"	Alert type discriminator.
timestamp	string (ISO 8601)	When the alert was triggered.
node	AosIdentity	Node where the threshold was exceeded.
parameter	string	Resource parameter name (e.g., cpu, ram).
value	integer	Triggered value of the parameter.

instanceQuotaAlert

Field	Type	Description
tag	"instanceQuotaAlert"	Alert type discriminator.
timestamp	string (ISO 8601)	When the alert was triggered.
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject identifier.
instance	integer	Instance number.
parameter	string	Resource parameter name.
value	integer	Triggered value.

downloadProgressAlert

Field	Type	Description
tag	"downloadProgressAlert"	Alert type discriminator.
timestamp	string (ISO 8601)	When the alert was triggered.
digest	string	Blob digest (OCI format, e.g., sha256:3c3a...).
url	string	Download URL (optional).
downloadedBytes	integer	Bytes downloaded so far.
totalBytes	integer	Total file size in bytes.
state	string	Download state: started, paused, interrupted, or finished.
reason	string	Reason for the current state (optional).
errorInfo	ErrorInfo	Error details if download failed.

deviceAllocateAlert

Field	Type	Description
tag	"deviceAllocateAlert"	Alert type discriminator.
timestamp	string (ISO 8601)	When the alert was triggered.
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject identifier.
instance	integer	Instance number.
node	AosIdentity	Node where allocation failed.
deviceId	string	Resource name that could not be allocated.
message	string	Error description.

updateItemInstanceAlert

Field	Type	Description
tag	"updateItemInstanceAlert"	Alert type discriminator.
timestamp	string (ISO 8601)	When the alert was triggered.
item	AosIdentity	Deployable Item identifier.
subjectId	AosIdentity	Subject identifier.
instance	integer	Instance number.
version	string (SemVer)	Item version.
message	string	Alert description.

Monitoring Data (Unit → Cloud)

The monitoringData message sends resource usage metrics from the Unit to the cloud, covering both node-level and per-instance metrics.

Message type: monitoringData

{
  "messageType": "monitoringData",
  "nodes": [...],
  "instances": [...]
}

Top-Level Fields

Field	Type	Required	Description
nodes	array of NodeMonitoringData	Yes	Per-node resource usage data.
instances	array of InstanceMonitoringData	No	Per-instance resource usage data.

NodeMonitoringData

Field	Type	Description
node	AosIdentity	Node identifier.
nodeStates	array of NodeState	Node state change history.
items	array of MonitoringData	Time-series resource usage records.

InstanceMonitoringData

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject identifier.
instance	integer	Instance number.
node	AosIdentity	Node where the instance runs.
itemStates	array of InstanceStateData	Instance state change history.
items	array of MonitoringData	Time-series resource usage records.

MonitoringData

A single resource usage sample.

Field	Type	Description
timestamp	string (ISO 8601)	When the sample was recorded.
ram	integer	RAM usage in bytes.
cpu	integer	CPU usage (implementation-defined units).
download	integer	Inbound network traffic in bytes.
upload	integer	Outbound network traffic in bytes.
partitions	array of PartitionUsage	Disk partition usage.

PartitionUsage

Field	Type	Description
name	string	Partition name.
usedSize	integer	Used space in bytes.

Log Messages

The protocol supports on-demand log retrieval. The cloud requests logs from the Unit, and the Unit responds with log content in parts.

requestLog (Cloud → Unit)

Requests logs from the Unit with filtering options.

Message type: requestLog

Field	Type	Description
logType	string	Type of log: systemLog, instanceLog, or crashLog.
filter	LogFilter	Filter criteria for the log request.
uploadOptions	UploadOptions	How the Unit should deliver the logs.

LogFilter

Field	Type	Description
from	string (ISO 8601)	Start timestamp (inclusive).
till	string (ISO 8601)	End timestamp (exclusive).
nodeIds	array of AosIdentity	Nodes to collect logs from (all if omitted).
item	AosIdentity	Filter by Deployable Item (optional).
subject	AosIdentity	Filter by subject (optional).
instance	integer	Filter by instance number (optional).

UploadOptions

Field	Type	Description
type	string	Upload channel: wss (WebSocket) or https.
url	string	Base URL for upload (optional).
bearerToken	string	Authorization token (optional).
bearerTokenTtl	string (ISO 8601)	Token expiration time (optional).

pushLog (Unit → Cloud)

Delivers log content in response to a requestLog. Large logs are split into multiple parts.

Message type: pushLog

Field	Type	Description
correlationId	string	Links this response to the original requestLog.
node	AosIdentity	Node that produced the logs.
part	integer	Current part number (starting from 0).
partsCount	integer	Total number of parts.
content	string (Base64)	Log content for this part.
status	string	Log status: ok, failed, error, empty, or absent.
errorInfo	ErrorInfo	Error details if status indicates failure.

Certificate Lifecycle Messages

The protocol includes messages for managing the Unit's certificate lifecycle — renewal notifications, certificate signing requests, and installation confirmations.

renewCertificatesNotification (Cloud → Unit)

Cloud notifies the Unit that certificates need renewal and provides unit secrets for secure operations.

Message type: renewCertificatesNotification

Field	Type	Description
certificates	array of CertificateIdentification	Certificates that need renewal (type, node, serial, validTill).
unitSecrets	UnitSecretsData	Secrets for secure Unit operations.

CertificateIdentification

Field	Type	Description
type	string	Certificate type: offline, online, um, sm, cm, iam, host-device, remote-device, or azure-iot.
node	AosIdentity	Node identity.
serial	string	Certificate serial number.
validTill	string (ISO 8601)	Certificate expiration time.

issueUnitCertificates (Unit → Cloud)

Unit requests new certificates by sending Certificate Signing Requests (CSRs).

Message type: issueUnitCertificates

Field	Type	Description
requests	array of IssueCertData	CSR requests.

IssueCertData

Field	Type	Description
type	string	Certificate type (same values as CertificateIdentification).
node	AosIdentity	Node identity.
csr	string (PEM)	Certificate Signing Request in PEM format.

issuedUnitCertificates (Cloud → Unit)

Cloud delivers newly issued certificates.

Message type: issuedUnitCertificates

Field	Type	Description
certificates	array of IssuedUnitCerts	Issued certificate data.

IssuedUnitCerts

Field	Type	Description
type	string	Certificate type.
node	AosIdentity	Node identity.
certificateChain	string (PEM)	Full certificate chain.

installUnitCertificatesConfirmation (Unit → Cloud)

Unit confirms that certificates have been installed (or reports failure).

Message type: installUnitCertificatesConfirmation

Field	Type	Description
certificates	array of InstallCertData	Installation results.

InstallCertData

Field	Type	Description
type	string	Certificate type.
node	AosIdentity	Node identity.
serial	string	Installed certificate serial number.
errorInfo	ErrorInfo	Error details if installation failed.

Service State Messages

The protocol supports bidirectional service state synchronization between the Unit and cloud.

newState (Unit → Cloud)

Unit reports a new service state (e.g., after a service writes updated state data).

Message type: newState

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject identifier.
instance	integer	Instance number.
stateChecksum	string	SHA-256 digest over the state content.
state	string	The state content (application-defined format).

updateState (Cloud → Unit)

Cloud sends updated state to the Unit (e.g., restoring state after redeployment).

Message type: updateState

Same schema as newState — contains item, subject, instance, stateChecksum, and state fields.

stateRequest (Unit → Cloud)

Unit requests its current or default state from the cloud.

Message type: stateRequest

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject identifier.
instance	integer	Instance number.
default	boolean	If true, request the initial (default) state. If false, request the latest state.

stateAcceptance (Cloud → Unit)

Cloud accepts or rejects a state update previously sent via newState.

Message type: stateAcceptance

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
subject	AosIdentity	Subject identifier.
instance	integer	Instance number.
checksum	string	State checksum being accepted/rejected.
result	string	Result: accepted or rejected.
reason	string	Reason for the decision.

Blob URL Messages

For large binary objects (Deployable Item images), the Unit requests download URLs from the cloud rather than receiving the data inline.

requestBlobUrls (Unit → Cloud)

Unit requests download URLs for specific blobs identified by their OCI digest.

Message type: requestBlobUrls

Field	Type	Description
digests	array of string	OCI-format digests (e.g., sha256:3c3a4604...).

blobUrls (Cloud → Unit)

Cloud provides download URLs and Verification information for requested blobs.

Message type: blobUrls

Field	Type	Description
items	array of UpdateItemBlobInfo	Blob download information.

UpdateItemBlobInfo

Field	Type	Description
digest	string	OCI-format blob digest.
urls	array of string	Download URLs (multiple for redundancy).
sha256	string (Base64)	SHA-256 hash of the blob content.
size	integer	File size in bytes.
decryptInfo	DecryptInfo	Decryption parameters for the blob.
signInfo	SignInfo	Signature Verification data.

DecryptInfo

Field	Type	Description
blockAlg	string	Block cipher: AES256/CBC/pkcs7 or AES256/GCM/.
blockIv	string (Base64)	Initialization vector.
blockKey	string (Base64)	Symmetric encryption key.

SignInfo

Field	Type	Description
chainName	string	Certificate chain name for Verification.
alg	string	Signing algorithm: RSA/SHA256 or EC/SHA256.
value	string (Base64)	Signature value.
trustedTimestamp	string (ISO 8601)	Signature timestamp.
ocspValues	array of string	OCSP response values.

Environment Variable Override Messages

The cloud can override environment variables for running service instances.

overrideEnvVars (Cloud → Unit)

Cloud sends environment variable overrides to apply to service instances.

Message type: overrideEnvVars

Field	Type	Description
items	array of EnvVarFilter	Filters and variables to apply.

EnvVarFilter

Field	Type	Description
item	AosIdentity	Target Deployable Item (optional — applies to all if omitted).
subject	AosIdentity	Target subject (optional).
instance	integer	Target instance number (optional).
variables	array of EnvVar	Environment variables to set.

EnvVar

Field	Type	Description
name	string	Variable name (1–256 characters).
value	string	Variable value (0–10240 characters).
ttl	string (ISO 8601)	Time-to-live for the variable (optional; empty means permanent).

overrideEnvVarsStatus (Unit → Cloud)

Unit reports the result of applying environment variable overrides.

Message type: overrideEnvVarsStatus

Field	Type	Description
statuses	array of EnvVarInstanceStatus	Per-instance override results.

EnvVarInstanceStatus

Field	Type	Description
item	AosIdentity	Deployable Item identifier.
subjectId	AosIdentity	Subject identifier.
instance	integer	Instance number.
name	string	Variable name.
errorInfo	ErrorInfo	Error details if override failed.

Provisioning Messages

The protocol supports remote provisioning and deprovisioning of nodes through a request/response pattern.

startProvisioningRequest (Cloud → Unit)

Cloud initiates provisioning of a node.

Message type: startProvisioningRequest

Field	Type	Description
node	AosIdentity	Node to provision.
password	string	TPM security officer password.

startProvisioningResponse (Unit → Cloud)

Unit responds with CSRs for the node's certificates.

Message type: startProvisioningResponse

Field	Type	Description
node	AosIdentity	Node being provisioned.
errorInfo	ErrorInfo	Error details if provisioning start failed.
csrs	array of CSR	Certificate Signing Requests (type + PEM CSR).

finishProvisioningRequest (Cloud → Unit)

Cloud completes provisioning by delivering signed certificates.

Message type: finishProvisioningRequest

Field	Type	Description
node	AosIdentity	Node being provisioned.
certificates	array of IssuedCertificate	Signed certificates (type + chain).
password	string	TPM security officer password.

finishProvisioningResponse (Unit → Cloud)

Unit confirms provisioning completion.

Message type: finishProvisioningResponse

Field	Type	Description
node	AosIdentity	Node that was provisioned.
errorInfo	ErrorInfo	Error details if provisioning failed.

deprovisioningRequest (Cloud → Unit)

Cloud initiates deprovisioning of a node.

Message type: deprovisioningRequest

Field	Type	Description
node	AosIdentity	Node to deprovision.
password	string	TPM security officer password.

deprovisioningResponse (Unit → Cloud)

Unit confirms deprovisioning completion.

Message type: deprovisioningResponse

Field	Type	Description
node	AosIdentity	Node that was deprovisioned.
errorInfo	ErrorInfo	Error details if deprovisioning failed.

Service Discovery Protocol

Before establishing the WebSocket connection, the Unit must discover the cloud endpoint through a lightweight HTTP-based service discovery mechanism.

Discovery Request

The Unit sends an HTTP POST to /sd/v7/ with:

{
  "version": 7,
  "systemId": "unit-abc-123",
  "supportedProtocols": ["ws/v7"]
}

Field	Type	Description
version	integer	Protocol version (7).
systemId	string	Unit system identifier.
supportedProtocols	array of string	Protocols the Unit supports.

Discovery Response

The cloud responds with connection information:

{
  "version": 7,
  "systemId": "unit-abc-123",
  "nextRequestDelay": 3600,
  "connectionInfo": ["wss://cloud.example.com/ws/v7/"],
  "authToken": "<optional-token>",
  "errorCode": "NoError"
}

Field	Type	Description
version	integer	Protocol version.
systemId	string	Confirmed Unit system ID.
nextRequestDelay	integer	Seconds before the Unit should re-discover.
connectionInfo	array of string	WebSocket URLs to connect to.
authToken	string	Optional authentication token.
errorCode	string	Status: NoError, Redirect, RepeatLater, or Error.

The Unit caches the discovered URL and reuses it across reconnections. A new discovery is triggered after repeated connection failures or when nextRequestDelay expires.

Protocol Behavior Summary

Message Flow Patterns

Pattern	Messages	Description
Status reporting	unitStatus → ack	Unit periodically reports its full or delta status.
Desired state	desiredStatus → ack	Cloud pushes target state; Unit acknowledges and begins reconciliation.
Blob download	requestBlobUrls → blobUrls	Unit requests download URLs for large binaries.
Log retrieval	requestLog → pushLog (×N)	Cloud requests logs; Unit responds in parts.
Certificate renewal	renewCertificatesNotification → issueUnitCertificates → issuedUnitCertificates → installUnitCertificatesConfirmation	Full certificate renewal cycle.
Provisioning	startProvisioningRequest → startProvisioningResponse → finishProvisioningRequest → finishProvisioningResponse	Node provisioning handshake.
State sync	newState → stateAcceptance	Unit uploads state; cloud accepts or rejects.

Connection Lifecycle

1. Service discovery — HTTP POST to /sd/v7/ returns WebSocket URL
2. WebSocket connect — mTLS handshake to /ws/v7/
3. Initial status — Unit sends full unitStatus (isDeltaInfo: false)
4. Steady state — bidirectional message exchange with ack/nack
5. Reconnection — on connection loss, exponential backoff from 1 second to 10 minutes, up to 5 retries per attempt

Related Pages

• Cloud Communication Overview — high-level architecture of the Unit-Cloud communication channel
• Connection Management — reconnection logic, keepalive, and error handling

• Communication Manager — the CM component that implements this protocol on the Unit side
• Security Model — certificate architecture and mTLS infrastructure

• Service Lifecycle — how desired-state messages drive service deployment
• Monitoring — monitoring pipeline that produces monitoringData messages