Unformatted text preview: FIN arrived for a connection that
18.7 The party that dials the number does the active open. The party whose telephone
rings does the passive open. Simultaneous opens are not permitted, but a simultaneous
close is OK.
18.8 We would only see ARP requests, not TCP SYN segments, but the ARP requests
would have the same timing as in the figure.
18.9 The client is on the host solaris and the server is on the host bsdi. The client's
ACK of the server's SYN is combined with the first data segment from the client (line 3).
This is perfectly legal under the rules of TCP, although most implementations don't do
this. Next, the client sends its FIN (line 4) before waiting for the ACK of its data. This
allows the server to acknowledge both the data and the FIN in line 5.
This exchange (sending one segment of data from the client to the server) requires seven
segments. The normal connection establishment and termination (Figure 18.13), along
with a single data segment and its acknowledgment, requires nine segments.
18.10 First, the server's ACK of the client's FIN is normally not delayed (we discuss
delayed ACKs in Section 19.3) but sent as soon as the FIN arrives. It takes the
application a while to receive the EOF and tell its TCP to close its end of the connection.
Second, the server that receives the FIN does not have to close its end of the connection
on receiving the FIN from the client. As we saw in Section 18.5, data can still be sent. file:///D|/Documents%20and%20Settings/bigini/Doc...omenet2run/tcpip/tcp-ip-illustrated/append_d.htm (12 of 20) [12/09/2001 14.48.04] Appendix D: Solutions to Selected Exercises 18.11 If an arriving segment that generates an RST has an ACK field, the sequence
number of the RST is the arriving ACK field. The ACK value of 1 in line 6 is relative to
the ISN of 26368001 in line 2.
18.12 See [Crowcroft et al. 1992] for comments on layering.
18.13 Five queries are issued. Assume there are three packets to establish the connection,
one for the query, one to ACK the query...
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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.
- Spring '12