README.notes
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- Test Scenarios:
- ---------------------------------------------------
- Look at time-sequence plot, infer TCP characteristics.
- One-way bulk data transfer.
- 1. Send N data packets in all, no losses. Check for Delayed Acks
- (Sec. 3.7 of ID), initial windows, slow start (Sec. 3.1 of ID),
- receivers advertised window. Check for FIN exchange (Sec. 3.8 of ID).
- 2. Drop the SYN packet. Check initial RTO.
- 3. Drop the first data packet. Check RTO after one RTT measurement.
- 3A. Repeat 3, also dropping the first retransmitted packet. Check for
- retransmit timer backoff.
- 3B: Repeat 3, dropping every retransmitted packet. Check for when
- connection terminates.
- 4. Drop a single data packet 20 or more data packets have been sent.
- Check for Fast Retransmit instead of Slow-Start.
- Check for failure of receiver to retain above-sequence data
- (Sec. 3.4 of ID).
- 4A. Repeat 4, also dropping the first retransmitted packet. Check for more
- or less aggressive implementations of SACK (depending on whether it
- waits for a retransmit timer.)
- 5. Drop an entire congestion window of packets, forcing a
- Retransmit Timeout. (How to do this: Drop packet N,
- and drop all succeeding data packets until you see a
- data packet with retransmitted data.) Check for Slow-start
- (Sec. 3.2 of ID), check RTO and make inferences about TCP
- clock granularity.
- 6. Drop a single data packet after many packets have gone by.
- Let K dup acks go by in the other direction, and then drop
- all succeeding dup acks until a new ack is seen. Repeat
- for K=1,2,3,4. Check for dup ack threshold, any responses
- to one or two dup acks.
- 7. Drop K consecutive packets after many packets have gone by. Check for
- Tahoe (slow-start after retransmit timeout or Fast Recovery), Reno
- (might or might not have to wait for a Retransmit Timeout,
- depending both on K and on the number of dup acks), NewReno,
- SACK (no unnecessary retransmission of packets even for K=2)
- 8. Multiple Fast Retransmits. Reproduce Figure 11 of the Simulator Tests document.
- 9. Drop first and last packet from a congestion window. (Figure 3 of
- "Simulation-based Comparisons of Tahoe, Reno, and SACK TCP"). Look
- for Tahoe vs. Reno vs. New-Reno or SACK.
- 10. Drop packets N, N+2, N+4, N+6, for large N. Check for retransmit timeout
- for Reno, not for Tahoe, NewReno, or SACK. (Figure 4 of
- " Simulation-based Comparisons of Tahoe, Reno, and SACK TCP".)
- Sec. 3.9 of ID: a large, interrupted bulk transfer.
- Sec. 3.10 of ID: a transfer in which the receiving application terminates abnormally.
- Tests of SACK vs. FACK.
- Two-way TCP
- Initial window on restart.
- ---------------------------------------------------
- Uses:
- Testing researchers' experimental implementations - SACK, ECN, NewReno.
- Testing production TCP implementations.
- Testing beta TCP implementations (e.g., Windows 98, NT 5, etc.)
- Testing a TCP connection when you don't have access to the remote
- end, and are curious about what generation of TCP they are using.
- Plug into tcpanaly: