Chapter 3

How to build a network?

2

Objectives

• What is a Network?

• IP Addresses

• Key Components of a Network (NIC)

• Factors in Designing a Network

3

What is a Network?

• A connection between at least two computers for the purpose of sharing resources (files, DB, printer etc.)

• Types:– Peer to Peer– Client and Server

4

Peer-to-Peer Network

• Computers linked together as equals

• No centralized control

• Share resources on the same network in any way and any time

• Promotes institutionalized chaos

• < 10 computers

5

Client/Server Network

• Server – designed to address a client’s request

• Client – any computer connected to a server within a network

• A cluster of computers (called clients) connected to one or more servers to form a network

• Allow authorized user to access any programs/application resided on the server

6

IP Address

• Why? Identify network computer• A host number that identifies

itself to other hosts• Find your computer’s IP: cmd ->

ipconfig• E.g. 191.170.64.12 • Host Name

– Human-friendly internet addresses– E.g. ema3z.mcintire.virginia.edu

7

URL vs. IP

• Zone– Three-letter kind (com, gov, edu)– Two-letter kind (ca, uk, jp)– New general-purpose zones (firm,

store)– Last (rightmost) part of a domain

name preceded by a dot

8

Data Transfer over Network

• Packet– Grouping of data for transmission on a

network– Large messages are split into a series of

packets for transmission• Protocol

– A rule governing how communication should be conducted between two parties, two computers, or a sources and a destination

– Internet Protocol• Set of rules used to pass packets

9

Key Components of A Network

• Network Interface Card (NIC)

• Routers

10

Network Interface Card

• Installed in a slot with a cable plugged into the back

• Plugged into a wall jack connection or into the hub/switch directly

• Modem – Converts digital signals into analog

form for transmission and incoming analog signals into digital signal across the telephone line

11

Routers

• LAN to LAN• Evaluate network traffic and

stop local traffic from causing congestion

• Filter out packets that need not be received

• Expensive and difficult to operate

12

Factors in Designing a Network

• Capacity – how many?• Cost – how much?• Potential growth

(scalability)• Security – how safe?

13

Test help

• What is a client?• What is the function of the Internet layer?• What is a microwave transmission?• What is TCP?• What is a macro?

14

Summary

• What is a Network?

• IP Addresses

• Key Components of a Network (NIC)

• More Factors in Designing a Network