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Unformatted text preview: ntroduc.htm (5 of 20) [12/09/2001 14.46.31] Chapter 1. Introduction Figure 1.4 Various protocols at the different layers in the TCP/IP protocol suite.
TCP and UDP are the two predominant transport layer protocols. Both use IP as the network
TCP provides a reliable transport layer, even though the service it uses (IP) is unreliable.
Chapters 17 through 22 provide a detailed look at the operation of TCP. We then look at some
TCP applications: Telnet and Riogin in Chapter 26, FTP in Chapter 27, and SMTP in Chapter
28. The applications are normally user processes.
UDP sends and receives datagrams for applications. A datagram is a unit of information (i.e., a
certain number of bytes of information that is specified by the sender) that travels from the
sender to the receiver. Unlike TCP, however, UDP is unreliable. There is no guarantee that the
datagram ever gets to its final destination. Chapter 11 looks at UDP, and then Chapter 14 (the
Domain Name System), Chapter 15 (the Trivial File Transfer Protocol), and Chapter 16 (the
Bootstrap Protocol) look at some applications that use UDP. SNMP (the Simple Network
Management Protocol) also uses UDP, but since it deals with many of the other protocols, we
save a discussion of it until Chapter 25.
IP is the main protocol at the network layer. It is used by both TCP and UDP. Every piece of
TCP and UDP data that gets transferred around an internet goes through the IP layer at both end file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/introduc.htm (6 of 20) [12/09/2001 14.46.31] Chapter 1. Introduction systems and at every intermediate router. In Figure 1.4 we also show an application accessing IP
directly. This is rare, but possible. (Some older routing protocols were implemented this way.
Also, it is possible to experiment with new transport layer protocols using this feature.) Chapter
3 looks at IP, but we save some of the details for later chapters where their discussion makes
more sense. Chapters 9 and 10 look at how IP performs routing.
ICMP is an adjunct to IP. It is used by the I...
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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