Smallport

Smallport is a lightweight transport protocol designed for resource-constrained environments. It emphasizes small header overhead, deterministic processing, and straightforward implementation, making it suitable for embedded devices, sensor networks, and microservices that require low-latency communication.

Its architecture favors transport-agnostic operation. Smallport uses a simple length-prefix framing over an underlying reliable or unreliable transport, with optional acknowledgments and basic sequencing. It provides lightweight multiplexing via stream identifiers and aims for a small code footprint and predictable execution time, enabling real-time or near-real-time behavior on limited hardware.

Security and interoperability: Security is optional and typically implemented as an upper-layer module, with support for TLS or DTLS where available. The design favors compact binary encodings to minimize bandwidth and parsing cost. A core set of control messages covers connection establishment, keep-alives, and error reporting, along with straightforward error codes.

History and usage: Smallport emerged from research in the 2010s as an approach to reduce protocol overhead in constrained networks. It has seen adoption in several open-source IoT projects and hobbyist firmware. Implementations exist in multiple languages, including C and Rust, with bindings for higher-level languages. A family of reference implementations and test suites supports interoperability and benchmarking.