TCP IP Illustrated

Lines 9 12 show the normal connection termination

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Unformatted text preview: and printed, to verify that both ends are indeed talking to each other. Figure 18.18 shows the exchange of segments across the connection. (We have deleted some new TCP options that appear in the original SYN from vangogh, a 4.4BSD system. We describe these newer options in Section 18.10.) Notice the two SYNs (lines 1 and 2) followed by the two SYNs with ACKs (lines 3 and 4). These perform the simultaneous open. Line 5 shows the input line "hello, world" going from bsdi to vangogh, with the acknowledgment in line 6. Lines 7 and 8 correspond to the line "and hi there" going in the other direction. Lines 9-12 show the normal connection termination. Many Berkeley-derived implementations do not support the simultaneous open correctly. On these systems, if you can get the SYNs to cross, you end up with an infinite exchange of segments, each with a SYN and an ACK, in each direction. The transition from the SYN_SENT state to the SYN_RCVD state in Figure 18.12 is not always tested in many implementations. file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/tcp_conn.htm (24 of 37) [12/09/2001 14.47.16] Chapter 18. TCP Connection Establishment and Termination 1 0.0 2 0.213782 (0.2138) 3 0.215399 (0.0016) 4 0.340405 (0.1250) 5.633142 (5.2927) 6.100366 6 (0.4672) 9.640214 7 (3.5398) 9.796417 8 (0.1562) 13.060395 9 (3.2640) 13.061828 10 (0.0014) 13.079769 11 (0.0179) 13.299940 12 (0.2202) 5 bsdi.8888 >vangogh.7777: S 91904001:91904001(0) win 4096 <mss 512> vangogh.7777 > bsdi.8888: S 1058199041:1058199041(0) win 8192 <mss 512> bsdi.8888 > vangogh.7777: S 91904001:91904001(0) ack 1058199042 win 4096 <mss 512> vangogh.7777 > bsdi.8888: S 1058199041:1058199041(0) ack 91904002 win 8192 <mss 512> bsdi.8888 > vangogh.7777: P 1:14(13) ack 1 win 4096 vangogh.7777 > bsdi.8888: . ack 14 win 8192 vangogh.7777 > bsdi.8888: P 1:14(13) ack 14 win 8192 bsdi.8888 > vangogh.7777: . ack 14 win 4096 vangogh.7777 > bsdi.8888: F 14:14(0) ack 14 win 8192 bsdi.8888 >...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.

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