ch03 IP Addressing.pdf - The Cisco Learning Network

2 Chapter 3: IP Addressing
The Transmission Control Protocol/Internet Protocol (TCP/IP) is a standard
that includes many protocols. It defines how machines on an internetwork can
communicate with each other. It was initially funded by and developed for DARPA
(Defense Advanced Research Protects Agency), which is a conglomeration of U.S. military and
government organizations. Developed initially for the government, it was later made available
to the public, mainly seen on Unix systems. First specified in RFC 791, it has become the
defacto standard for networking protocols. The Internet uses TCP/IP to carry data between
networks, and most corporations today use TCP/IP for their networks. This chapter will
provide an overview of TCP/IP, including some of its more important protocols, as well as
IP addressing.
It is VERY important
that you understand ALL aspects of IP
addressing. Therefore, spend a lot of time
on this chapter. If you don’t understand IP
CERTIFICATION OBJECTIVE 3.01
TCP/IP Protocol Stack
Application Layer
addressing when taking the exam, you
will have a difficult time in passing it.
This Exam Watch goes for all three
exams: INTRO, ICND, and CCNA.
To help articulate how data is moved between devices running TCP/IP, a model was
developed that resembles the OSI Reference Model discussed in Chapter 2. Table 3-1
compares the two models. The following sections will cover the layers of the TCP/IP
Protocol stack.
One main difference between the OSI Reference Model and TCP/IP’s model is that
TCP/IP lumps together the application, presentation and session layers into one layer,
called the application layer. Here are some common TCP/IP applications Cisco devices
support: DNS, HTTP, SNMP, telnet, and TFTP.