| Now that you have completed this
chapter, you should have a firm understanding of the following:
Networks are groups of interconnected
computers. Local Area Networks (LANs) and Wide Area Networks (WANs)
are two basic categories of networks. If computers are relatively
close together and the networking equipment and cabling are owned by
the organization, this is a LAN. WANs are created by interconnecting
two or more geographically separate LANs. The links interconnecting
the LANs are not typically owned by the organization. Routers are
generally used to connect LANs to WANs.
The computers and networking equipment
on both LANs and WANs are connected using various types of media
including copper, fiber optic, and various forms of wireless
communications.
Ethernet is the most common LAN
architecture or technology. Other LAN technologies include Token Ring
and FDDI. Switched Ethernet using an extended star topology is the
dominant LAN technology being deployed today. Examples of WAN
technologies include T1, Frame Relay, ISDN, and ATM.
The most popular data communications
protocol is TCP/IP, which is actually a suite of protocols. The
Internet and many LANs and WANs use the TCP/IP protocol. Several
utilities are part of the TCP/IP protocol suite including: ping,
telnet,
rlogin
and ftp.
The ping
command is a low-level
troubleshooting tool. Telnet
can be used to take over the console of a remote host. Rlogin
is used to login and run programs on another computer. FTP
or File transfer Protocol is a very useful utility that can be used to
transfer file between computers with dissimilar operating systems.
Client server architecture is a popular
computing model used with the Internet. It is used to distribute or
share processing loads when performing tasks. The server or backend
runs software such as a daemon to provide services for client
requests.
Sun developed NIS+ and NFS. NIS+
simplifies network administration by providing a centralized database
for user account authorization. NFS provides for distributed
processing by allowing a file system on a remote computer to appear as
part of the local hosts file system. |