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Unformatted text preview: , one for the response, one to ACK the response,
and four to terminate the connection. This means II packets per query, for a total of 55
packets. Using UDP reduces this to 10 packets.
This can be reduced to 10 packets per query if the ACK of the query is combined with the
response (Section 19.3).
18.14 The limit is about 268 connections per second: the maximum number of TCP port
numbers (65536 -1024 = 64512, ignoring the well-known ports) divided by the
TIME_WAIT state of 2MSL.
18.15 The duplicate FIN is acknowledged and the 2MSL timer is restarted.
18.16 The receipt of an RST while in the TIME_WAIT state causes the state to be
prematurely terminated. This is called TIME_WAIT assassination. RFC 1337 [Braden
1992a] discusses this in detail and shows the potential problems. The simple fix proposed
by this RFC is to ignore RST segments while in the TIME_WAIT state.
18.17 It's when the implementation does not support a half-close. Once the application
causes a FIN to be sent, the application can no longer read from the connection.
18.18 No. Incoming data segments are demultiplexed using the source IP address, source
port number, destination IP address, and destination port number. For incoming
connection requests we saw in Section 18.11 that a TCP server can normally prevent
connections from being accepted based on the destination IP address. Chapter 19
19.1 Two application writes, followed by a read, cause a delay because the Nagle
algorithm will probably be invoked. The first segment (with 8 bytes of data) is sent and
its ACK is waited for before sending the 12 bytes of data. If the server implements
delayed ACKs, there can be a delay of up to 200 ms (plus the RTT) before this ACK is
19.2 Assuming 5-byte CSLIP headers (IP and TCP) and 2 bytes of data, the RTT across
the SLIP link for these segments is about 14.5 ms. We have to add to this the RTT across file:///D|/Documents%20and%20Settings/bigini/Doc...omenet2run/tcpip/tcp-ip-illustrated/append_d.htm (13 of 20) [12/09/2001 14.48.04] Appendix D: Solutions...
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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