CHAPTER 21. NETWORKBy: Morgan Sherrill, Brandie Barksdale, Kyle Coleman

Servers and Clients

Servers- share things like files and printers

Clients- enables access to the severs files

Any computer can be a server or a client

Network Machines

Computers of today slightly resemble the computers from the old days

Old computers were the size of a room and now there are mini computers that can fit in your lap

Old computers could only process hugely complex mathematical equations that’s it now computers

Supercomputers, Mainframes and Minicomputers

Supercomputers and mainframes are the most powerful servers

Supercomputers are extremely fast computer dedicated to performing one task very well

Mainframes are almost like supercomputers with the firepower but mainframes focus on enabling hundreds or thousands of people to work on many different programs simultaneously

Minicomputers enable many people to access a multitude of programs at a much lower prices then a supercomputer or a mainframe

IMB PC-based Microcomputers Servers

The most common minicomputer is based on the original IBM x86 architecture

The severs in this family use Intel or AMD processors and have multiple hard drives to supply safety for your data if one of the drives fails

Server PCs are in two basic physical shapes: tower and rack-mounted

Apple Microcomputer Servers

Apple makes a version of its popular Macintosh hardware and operating system designed specifically for servers called Xserver

Xserver servers use Motorola and IBM G5 CPUs can have multiple processors, gobs of RAM, and tons

Linux on the Inside

Linux is the odd duck operating system, because you can run it on IBM-style Pc’s, Xserve G5 machines, and most mainframes.

Linus Torvalds, a programmer from Finland, created the first version of Linux.

Linus wrote the computer code for an operating system based on UNIX, posted it on the Internet, and told other programmers that if they could make it better, they were welcome to do so.

UNIX

The UNIX family of operating systems grew up in the heyday of mainframe and minicomputers, and continues to thrive on x86-based microcomputers

Dozens of versions of UNIX run on serve computers, but the most popular are *BSD IBM AIX, and solaris

Creating your Network

To create a network you need to connect a client computer with a server in some way

Most often, you’ll use a wire, but you could do it through radio waves to create a wireless connection

Let’s look at two common types of networks, then turn to network hardware

Network Types

Network come in many sizes and vary a lot in the number of computers attached to them

Some people connect two computers in their house so that they can share files and play games together

Some companies have thousands of employees in dozens of countries, in contrast, and need to network their computers together to get work done

Network Hardware

Whether you want to put together a LAN or connect a couple of LAN’s into a WAN, you’ve got to have connectivity between the PCs and a way to handle communication

Computers connect to a network in one of three ways: directly wired to a LAN via a cable from the computer to LAN port; wirelessly to the LAN; and via a telephone line, what’s called dial-up networking

Wired Network

A typical network client has a network adapter or network interface card that connects to a cable, connects to a central network box, called a hub or switch

Networking Process

Once you’ve assembled the pieces for a network, you can sit down at a client computer and access a file on a server

Hardware and Software: Tango in Paris

It takes both hardware and software to make network communication work well.

HUB versus Switch

Hubs and switches function quite differently when they receive an Ethernet frame.

Wireless Components

It isn’t always practical to string network calling to every location where you need a network connection.

Modems and Dial-up

You can connect a computer to a network through a telephone line and a device called a modem, short for modulator/ demodulator.

Analog Versus Digital

When you map a sound wave you get an analog signal meaning the wave goes up and down in a smooth flow like a sine wave

With a digital that makes contrast you get hard 1s and 0s connected together into a pattern that makes sense to computer

Perils of Pauline: Benefits, Risks, and Security

A network can enhance your computing experience greatly but it can also invite risks to your data that would have been unimaginable in a non-networked computer.

This section talks about benefits and risks and what you or a network administrator someone in charge of configuring maintaining and defending the network need to do make a network secure

Upside of Network Computing

Networks offer many benefits over standalone computing in several somewhat overlapping categories

Enhanced communication and collaboration

Easier sharing of files and resources Lower costs because of the sharing Easier management of machines in

the network

Downside of Network Computing

Creating a computer network can add and cause security problems.

Principle of least Access

Outside of the fundamental principles of network security there are additional layers of network security that fall in line with what some have termed the principle of least assess (pola)