Plain answers on TR-369 (USP), TR-069 and GPON ONT operations, each fact traced to the Broadband Forum spec. From the engineers behind DWS Support.https://blog.dodderware.com/en-ushttps://blog.dodderware.com/what-is-tr-369/https://blog.dodderware.com/what-is-tr-369/TR-369 is the Broadband Forum specification of the User Services Platform (USP), an architecture, protocol and data model for managing, monitoring, troubleshooting and controlling connected devices. Software on the device, the Agent, exposes its data model to one or more Controllers, which exchange Protocol Buffers messages with it over WebSocket, MQTT, STOMP or UNIX domain sockets. It uses the same Device:2 (TR-181) data model as TR-069.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPTR-369USPUser Services PlatformTR-069CWMPTR-181Broadband Forumhttps://blog.dodderware.com/tr-069-vs-tr-369/https://blog.dodderware.com/tr-069-vs-tr-369/TR-069 (CWMP) and TR-369 (USP) are Broadband Forum protocols for managing customer devices, and they share the Device:2 data model of TR-181, so the same parameter paths carry over. What changes is everything around it. CWMP has a single ACS, while a USP Agent answers to one or more Controllers, each with its own Role, and exchanges Protocol Buffers messages over WebSocket, MQTT, STOMP or UNIX domain sockets.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPTR-069 vs TR-369CWMP vs USPTR-069TR-369USPCWMPACSTR-181https://blog.dodderware.com/usp-agent-vs-controller/https://blog.dodderware.com/usp-agent-vs-controller/In USP (TR-369), an Agent is the Endpoint that exposes Service Elements to one or more Controllers, and a Controller is the Endpoint that manipulates those Service Elements through one or more Agents. Each Endpoint is named by an Endpoint ID built as authority-scheme:[authority-id]:instance-id, such as oui:00256D:my-unique-bbf-id-42, where the scheme decides who guarantees that the ID is unique.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPUSP AgentUSP ControllerEndpoint IDTR-369USP Endpointauthority-schemeBroadband Forumhttps://blog.dodderware.com/usp-mtp-websocket-mqtt-stomp/https://blog.dodderware.com/usp-mtp-websocket-mqtt-stomp/TR-369 defines four Message Transfer Protocols (MTPs) to carry USP Records. WebSocket links an Agent and a Controller directly over one long-lived session. STOMP and MQTT route Records through a broker, by destination or by Topic. The UNIX Domain Socket MTP connects an Agent and a Controller running as separate processes on the same device. CoAP was obsoleted in USP 1.3.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPUSP MTPTR-369 WebSocketUSP over MQTTUSP over STOMPUNIX domain socketMessage Transfer Protocolhttps://blog.dodderware.com/tr-369-security/https://blog.dodderware.com/tr-369-security/TR-369 secures USP at three levels. Each Message Transfer Protocol must use secure transport, normally TLS, when traffic crosses network boundaries. When brokers or proxies sit in the path, Secure Message Exchange can run TLS inside USP Records between the two Endpoints. And every Controller is authenticated and given a Role, whose rwxn permissions the Agent checks before acting on a Message.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPTR-369 securityUSP securityUSP TLSSecure Message ExchangeTrust On First UseTrusted BrokerUSP roleshttps://blog.dodderware.com/usp-firmware-upgrade/https://blog.dodderware.com/usp-firmware-upgrade/In TR-369, a Controller upgrades firmware by invoking Download(), through an Operate message, on an instance of the Device.DeviceInfo.FirmwareImage table. The Agent downloads the file into that image slot and validates it, checksum included. A single-image device activates it at once with AutoActivate. A device with two or more images downloads to a non-active slot, then switches with Activate() or a reboot.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPUSP firmware upgradeTR-369 firmwareDownload()Activate()FirmwareImagedual image firmwareOperationCompletehttps://blog.dodderware.com/usp-notifications-subscriptions/https://blog.dodderware.com/usp-notifications-subscriptions/USP (TR-369) has no Subscribe message. A Controller subscribes by using Add to create a row in the Agent’s Device.LocalAgent.Subscription. table. When the subscribed event occurs, the Agent sends a Notify carrying a ValueChange, ObjectCreation, ObjectDeletion, OperationComplete or Event notification, such as Boot!. If NotifRetry is on, the Agent asks for a response and retries until it gets one or the notification expires.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPUSP notificationsUSP subscriptionTR-369 NotifyValueChangeOperationCompleteBoot! eventTR-369https://blog.dodderware.com/usp-discovery-dhcp-mdns/https://blog.dodderware.com/usp-discovery-dhcp-mdns/A USP Agent needs its Controller’s Endpoint ID, credentials and Role, and enough to reach it, meaning an MTP, address, port and path. TR-369 lets that come from firmware, from an already-trusted Controller, from a bootstrap interface or from the network. DHCPv4 option 125 or DHCPv6 option 17 can deliver one Controller’s URL or FQDN and Endpoint ID, and DNS-SD over DNS or mDNS resolves the rest.Wed, 28 Oct 2026 00:00:00 GMTTR-369 / USPUSP discoveryTR-369 DHCP option 125DNS-SDmDNSUSP ControllerUSP Agent_usp-agt-ws._tcpTR-369https://blog.dodderware.com/gpon-ont-optical-power/https://blog.dodderware.com/gpon-ont-optical-power/In DWS Support’s default bands, a GPON ONT’s RX optical power is healthy from −24 to −8 dBm, with an optimum around −14 dBm. Readings from −27 up to −24 dBm are a warning, and anything below −27 or above −8 dBm is critical. TX power is healthy from 0.5 to 5 dBm. These are product defaults, not a standard, and operators can set their own.Wed, 28 Oct 2026 00:00:00 GMTGPON and FTTH operationsGPON RX powerONT optical powerONT RX power dBmONT TX powerOpticalSignalLevelTR-181FTTH troubleshooting