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Unformatted text preview: 28.1, 29.9, and 35.3 ms. Given that there are two
links between sun and slip (an Ethernet and a 9600 bits/sec CSLIP link), do these time
differences make sense? (Hint: Reread Section 2.10.)
19.3 Compare the time required to send a special function key and have it acknowledged
using the Nagle algorithm (Figure 19.6) and with the algorithm disabled (Figure 19.8). file:///D|/Documents%20and%20Settings/bigini/Docu.../homenet2run/tcpip/tcp-ip-illustrated/tcp_int.htm (14 of 14) [12/09/2001 14.47.18] Chapter 20. TCP Bulk Data Flow TCP Bulk Data Flow
In Chapter 15 we saw that TFTP uses a stop-and-wait protocol. The sender of a data block
required an acknowledgment for that block before the next block was sent. In this chapter
we'll see that TCP uses a different form of flow control called a sliding window protocol. It
allows the sender to transmit multiple packets before it stops and waits for an
acknowledgment. This leads to faster data transfer, since the sender doesn't have to stop and
wait for an acknowledgment each time a packet is sent.
We also look at TCP's PUSH flag, something we've seen in many of the previous examples.
We also look at slow start, the technique used by TCP for getting the flow of data
established on a connection, and then we examine bulk data throughput. 20.2 Normal Data Flow
Let's start with a one-way transfer of 8192 bytes from the host svr4 to the host bsdi. We
run our sock program on bsdi as the server:
bsdi % sock -i -s 7777
The -i and -s flags tell the program to run as a "sink" server (read from the network and
discard the data), and the server's port number is specified as 7777. The corresponding client
is then run as:
svr4 % sock -i -n8 bsdi 7777
This causes the client to perform eight 1024-byte writes to the network. Figure 20.1 shows
the time line for this exchange. We have left the first three segments in the output to show
the MSS values for each end. file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/tcp_b...
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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