TCP: Reliable Transport

Lesson 6 · OKSTEM College · AS Computer Science

TCP: Reliable Transport

Work through the concepts, then test yourself with the knowledge check.

Interactive Lab

Knowledge Check

TCP guarantees delivery using:

Hardware error correction is at the Physical layer. TCP uses acknowledgments.

Correct — the receiver ACKs received segments; unACK'd segments are retransmitted.

TCP doesn't duplicate packets by default — it only retransmits unACK'd ones.

Checksums detect errors but don't cause retransmission by themselves.

📖 Quick Recap

TCP reliability uses ACKs, sequence numbers, and retransmission — pure software mechanisms. Hardware CRC only detects errors within a single hop.

📖 Quick Recap

Sending every packet twice would waste bandwidth. TCP retransmits selectively: only segments not acknowledged within a timeout.

📖 Quick Recap

The TCP checksum detects corruption. But reliability (ensuring delivery) requires ACKs + retransmission. A corrupted segment is detected and dropped; the sender retransmits on timeout.

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