Part III: Agents & Services

UnetStack is organized around services and agents. A service is a contract — a well-defined set of messages and parameters for a particular capability, such as transmitting a datagram, routing it across the network, or measuring the range to another node. An agent is a software component that implements one or more services (and may use the services of other agents to do its job). Higher layers interact with a capability through its service contract, without caring which agent provides it, so any agent can be swapped for another that honors the same contract.

This part is organized as follows:

• The default stack gives an overview of the agents loaded on every node, and points to where each one is documented.
• The service chapters that follow (from Node information onwards) each describe one service. They are written for two readers at once: a user who wants to consume the service, and a developer writing an agent that provides it. Each follows the same structure — the chapter opens with the purpose of the service, then defines the contract: the messages the service understands and generates (and the behaviors expected of a provider), the parameters it exposes, and, where applicable, the optional capabilities a provider may advertise. Examples show the service in use, and an Implementations section documents the concrete agent(s) that provide it — the default agent, plus alternative, simulator and licensed implementations — each with a summary table (class, services, capabilities, availability), a user-level explanation of how it works, and its agent-specific parameters. Agents that provide multiple services are documented under their primary service, with pointers from the others.
• Utility agents collects the agents that provide no service — helpers and tools such as the profile manager, speed test and signal monitor.

If you are new to UnetStack, read The default stack first to see what runs on a node and what each agent is for, then dip into the individual service chapters as you need the details.