What is a recovery procedure after a protocol-induced crash or disconnect?

• A. Re-establish connection, re-sync state, restart data transfer, and verify data integrity after recovery.
• B. Restart with a fresh connection and discard any partial state.
• C. Delete local data and terminate.
• D. Wait for manual intervention.

Answer: (A)

When a protocol crashes or disconnects, the goal is to recover while keeping data consistent and minimizing lost progress. The best recovery sequence re-establishes the connection, re-syncs the protocol state with the peer, restarts data transfer from a safe point, and then verifies data integrity after recovery.

Re-establishing the connection gets the two sides talking again and enables the necessary control messages to resume operation. Re-syncing the state aligns sequence numbers, acknowledgments, and any in-flight operations so both sides have a shared view and avoid duplicating or skipping data. Restarting the data transfer from a known good point ensures you don’t re-send data that’s already been safely received, while still completing any remaining work. Verifying data integrity after recovery catches any corruption and confirms the transfer is correct before continuing.

Other approaches—like starting fresh and discarding partial state, deleting local data and terminating, or waiting for manual intervention—either throw away progress, risk inconsistency, or introduce avoidable downtime.