This trace follows the actual state transitions behind the companion TCP Provides an Ordered Byte Stream. It describes a common execution path; implementation details can vary, so keep the contract separate from the mechanism.
Step 1: Write bytes to the socket
TCP provides applications with a reliable, ordered byte stream over an IP network. It tracks sequence numbers, acknowledges received ranges, retransmits data when needed, and applies flow and congestion control. The application sees a stream of bytes rather than message boundaries.
Step 2: Assign stream sequence space
A sender can write a short buffer, but TCP may combine it with other data or split it across segments. The receiver must parse its own framing format, such as a fixed length, delimiter, or length prefix. An acknowledgement confirms transport-level receipt, not that the remote application completed a business operation.
Step 3: Transmit and acknowledge data
The receiver gets an ordered byte stream, not the sender’s write boundaries; application code must detect a complete message using an explicit framing rule.
At this point, record the state that changed and check the invariant before advancing. If the operation repeats, make clear which values persist and which are recomputed.
Step 4: Recover missing ranges
Connections can stall, reset, or time out, and a successful local write does not prove remote delivery. Flow control protects the receiver; congestion control responds to network conditions. Retrying an application operation after uncertainty can duplicate side effects unless the operation is idempotent.
Step 5: Frame bytes in the application
An API sends two JSON objects over one TCP connection. Explain why a single read call cannot be assumed to return exactly one complete object, and propose a framing strategy.
The trace is complete when the result satisfies the stated contract. Compare this model with the concrete runtime or system you are studying before making a performance claim.