Receiveside

Receiveside is a term used in computing and networking to denote the portion of a system that handles inbound data traffic. It is not a formal standard but is commonly used to contrast with the sendside, which handles outbound traffic. In networked software, the receiveside encompasses the hardware, drivers, and software components responsible for receiving data, validating it, and delivering it to the appropriate consumer, such as a network application or service.

Key components of the receiveside include the network interface card (NIC), the device driver, and the operating system's networking stack, together with receive queues, buffers, and the interrupt or polling mechanisms that trigger data processing. The receiveside also includes any user-space components that directly process incoming data, such as packet capture or protocol handlers.

Typical processing steps involve hardware reception, buffering, demultiplexing of packets to a specific connection, packet header and payload processing, and delivery to upper-layer software. Security and integrity checks, decryption, and error handling may also occur on the receiveside. Performance optimizations commonly apply to the receiveside, such as receive-side scaling (RSS), which uses hashing to distribute inbound traffic across multiple CPU cores, and techniques like interrupt coalescing or NAPI-style polling to reduce processing overhead.

The balance between receiveside and sendside performance is important for overall system throughput and latency. In practice, tuning involves ensuring adequate receive queues, appropriate RSS configuration, and compatible driver and NIC support to avoid bottlenecks or unfairness among flows.

Related concepts include Receive-Side Scaling (RSS), interrupt moderation, and the Linux NAPI interface.