This preview shows page 1. Sign up to view the full content.
Unformatted text preview: tes and verifies a mandatory end-to-end
TCP is used by many of the popular applications, such as Telnet, Rlogin, FTP, and
electronic mail (SMTP).
17.1 We've covered the following packet formats, each of which has a checksum in its
corresponding header: IP, ICMP, IGMP, UDP, and TCP. For each one, describe what
portion of an IP datagram the checksum covers and whether the checksum is mandatory or
17.2 Why do all the Internet protocols that we've discussed (IP, ICMP, IGMP, UDP, TCP)
quietly discard a packet that arrives with a checksum error?
17.3 TCP provides a byte-stream service where record boundaries are not maintained
between the sender and receiver. How can applications provide their own record markers?
17.4 Why are the source and destination port numbers at the beginning of the TCP header?
17.5 Why does the TCP header have a header length field while the UDP header (Figure
11.2) does not? file:///D|/Documents%20and%20Settings/bigini/Docum.../homenet2run/tcpip/tcp-ip-illustrated/tcp_tran.htm (6 of 6) [12/09/2001 14.47.10] Chapter 18. TCP Connection Establishment and Termination TCP Connection Establishment and
TCP is a connection-oriented protocol. Before either end can send data to the other, a
connection must be established between them. In this chapter we take a detailed look at how a
TCP connection is established and later terminated.
This establishment of a connection between the two ends differs from a connectionless protocol
such as UDP. We saw in Chapter 11 that with UDP one end just sends a datagram to the other
end, without any preliminary handshaking. 18.2 Connection Establishment and Termination
To see what happens when a TCP connection is established and then terminated, we type the
following command on the system svr4:
svr4 % telnet bsdi discard
Trying 22.214.171.124 ...
Connected to bsdi.
Escape character is '^]'.
type Control, right bracket to talk to the Telnet client
terminate the connection
View Full Document
- Spring '12