Understanding TCP/IP Model Internals and Interfaces
Understanding TCP/IP Model Internals and Interfaces
Understanding TCP/IP Model Internals and Interfaces
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1508 <strong>Underst<strong>and</strong>ing</strong> <strong>TCP</strong>/<strong>IP</strong> <strong>Model</strong> <strong>Internals</strong> <strong>and</strong> <strong>Interfaces</strong><br />
2. Which two flavors tie for second place in application response time? <strong>TCP</strong> SACK, New Reno<br />
3. What flavor resulted in the highest response time <strong>and</strong> why? Reno<br />
It had to wait for a timeout before resending the third dropped segment.<br />
4. Why do you think <strong>TCP</strong> Reno with ECN support outperformed all other <strong>TCP</strong> flavors?<br />
It did not have to retransmit any segment.<br />
5. Why do you think <strong>TCP</strong> Reno performed worse than <strong>TCP</strong> Tahoe, which does not use fast<br />
recovery?<br />
It had to wait for retransmission timer expiration.<br />
<strong>TCP</strong> Tahoe:<br />
1. What was the congestion window before the packet loss was detected? 12,864 Bytes<br />
2. What was the congestion window after the loss was detected? 536 Bytes<br />
3. How did the server recover from packet loss, by using fast retransmit or timeout retransmission?<br />
Using fast recovery<br />
4. How many times was a slow start performed during the session lifetime?<br />
Slow start was performed twice – when the session opened <strong>and</strong> when the packet drop was<br />
detected.<br />
5. How many segments were retransmitted? 5<br />
6. Were any segments retransmitted unnecessarily? Yes, 2 of them<br />
7. When is the last segment sent? At about 1.4 sec<br />
<strong>TCP</strong> New Reno<br />
1. What was the congestion window before the packet loss was detected? 12,864 Bytes<br />
2. What was the congestion window after the loss was detected? 8,040 Bytes<br />
3. How did the server recover from packet loss, by using fast retransmit or timeout retransmission?<br />
Fast recovery<br />
4. How many times was a slow start performed during the session lifetime? once<br />
5. How many segments were retransmitted? 3<br />
6. Were any segments retransmitted unnecessarily? No<br />
7. When is the last segment sent? At about 1.2 sec<br />
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