1. Introduction to Networks
Lesson 1

2. Objectives Exam Objective Matrix Technology Skill Covered
Exam Objective Number
Basic Definitions
Describe different network topologies.
Peer-to-peer
Client-server
3.5
Basic Network Topologies
Point-to-point
Point-to-multipoint
Ring
Star
Mesh
Bus
Hybrid
Basic Network Configuration in Windows

3. A Brief History of Networking
First networks called “sneaker nets”
Transferred files between computers on floppy disks
Mainframe computers and dumb terminals
Defense Advanced Research Projects Agency (DARPA) created ARPAnet
Became Internet
Mid 1980s
PCs common in workplace

4. A Brief History of Networking (Continued)
Late 1980s
Businesses commonly networked PCs
July/August 1989
BryanNet at William Jennings Bryan College
First general use high speed network
Through put speeds of 2.5 mbps (megabits per second)
Token ring
Client/server

5. A Brief History of Networking (Continued)
Mid 1990s
World Wide Web established as a viable entity on the Internet
Hardware and software infrastructure
Internet
Service, or software, that runs on top of the infrastructure of the Internet
World Wide Web

6. Local Area Network (LAN)
A network limited to a local area
Usually limited to one building, or several buildings near one another
Sometimes limited to certain rooms in a building

7. Local Area Network (LAN) (Continued)
Peer-to-peer network
Each computer acts independently but can share data and resources, such as printers
Best used with 10 or fewer computers
Client/server
One main computer is server or domain controller
User accounts and resources available on one or more servers

8. Wide Area Network (WAN)
A very large network that can stretch across large geographical areas
Internet is biggest WAN in existence
Enterprise network
WANs in a company’s offices or buildings in widely dispersed areas that connect facilities and employees

9. Metropolitan Area Network (MAN)
A single network larger than a LAN but slightly too small to be considered a WAN
Is generally 50 kilometers maximum
Links college campuses or stretches across cities
Privately owned by an organization or publicly owned by a municipality
Term “MAN” falling out of usage, usually referred to as WAN or enterprise network

10. Basic Network Topologies
Shape of network = topology
Bus
Star
Ring
Mesh
Point-to-Point
Point-to-Multipoint
Hybrid

11. Bus Topology
All computers in network are connected by one main cable, called a backbone
Advantages
Easy to build and requires minimal amount of cable
Disadvantages
If cable breaks, networked computers cannot communicate
Signal collisions

12. Bus Network Topology

13. Most commonly used networking topology
Star Topology
Most commonly used networking topology
Several workstations connected via one central device such as a hub or a switch
Advantage
If cable to one computer goes bad, only that computer is affected
Disadvantage
If central connecting device goes bad, entire network does not work

14. Star Network Topology

15. Backbone cable is formed into a ring to connect all computers
Ring Topology
Backbone cable is formed into a ring to connect all computers
Advantage
Use of token avoids data collisions
Disadvantages
If backbone breaks, entire network goes down
Network becomes very slow when large amounts of data are being sent

16. Ring Topology Network

17. Most commonly used in a WAN environment
Mesh Topology
Every computer or building is connected directly to every other computer or building
Most commonly used in a WAN environment
Number of connections: n (n–1) /2
Advantages
Reliability, redundancy, high availability
Disadvantage
Number of connections grows quickly
A partial mesh network topology requires each device on the network to be able to connect to at least two other devices.
A partial mesh network topology has all the same advantages as a full mesh topology where redundancy is concerned; however, it also has the added benefit that it does not require as many connections.

18. Mesh Topology Network
A partial mesh network topology requires each device on the network to be able to connect to at least two other devices.
A partial mesh network topology has all the same advantages as a full mesh topology where redundancy is concerned; however, it also has the added benefit that it does not require as many connections.

19. Point-to-Point Topology
Only one computer is directly connected to one other computer or device
Primarily a WAN type topology
Most commonly used when a computer outside the network needs to remotely connect to a computer or server inside a network

20. Point-to-Multipoint Topology
A variation on the point-to-point topology but commonly used in both LANs and WANs
One device connects to several other devices
Most often used to connect one switch or router to multiple switches, routers, computers, or other network devices

21. Point-to-Multipoint Topology Network

22. Hybrid Topology
A hybrid or combination of several network topologies
Most networks are hybrid

23. Hybrid Topology Network
The network connection between the top ring, the middle router, and the bottom switch is an example of a bus topology.
The connection between the router and the Internet cloud is an example of a point-to-point topology connection between the router and the Internet Service Provider (ISP) that provides access to the Internet for the entire network.

24. Physical vs. Logical Topologies
Physical topology
The shape of the wires
Logical topology
The shape of the path the data follows as it moves through the network.

25. Physical Star Topology Using a Logical Bus Topology

26. Physical Star Topology Using a Logical Ring Topology
Similar to preceding figure but with one main difference. Instead of the central hub having a bus topology on the inside, it has a ring topology on the inside. A device like this is sometimes called a Token Ring Hub or a Ring Hub. One of the official names of a device like this is a MAU, which stands for Media Access Unit.

27. Basic Network Configuration in Windows
User Account Control
A feature of Windows Vista and Windows 7
Requires confirmation, and sometimes administrative passwords, to allow certain actions to be taken on a Windows Vista or Windows 7 computer, even when the person attempting the actions has administrative rights
Can become bothersome

28. Basic Network Configuration in Windows (Continued)
To turn off UAC in Windows Vista:
Open Control Panel.
Double-click the Security icon.
In the Security dialog box, turn off UAC in the Other security settings section.
TIP: It’s best to leave UAC enabled for general users. Professionals may turn off UAC temporarily when maintaining PCs.

29. Windows Vista Security Dialog Box

30. Basic Network Configuration in Windows (Continued)
Network and Sharing applet in Windows 7 and Windows Vista
All issues related to networking and sharing of files, folders, media, and so on are located here

31. Windows Vista Network and Sharing Center Dialog Box

32. Summary
In organizations, PCs were common by the mid 1980s and networked PCs by the late 1980s.
The Internet is the hardware and software infrastructure on which the World Wide Web (a service or program) runs.
A LAN is a local network. A MAN is a campus or city-wide network. A WAN covered a wide geographic area.
All computers are “equal” on a peer-to-peer network.

33. Summary (Continued)
A client/server network has a server or domain controller to which users connect and access shared resources.
Network topologies include bus, star, ring, mesh, point-to-point, point-to-multipoint, and hybrid.
Physical topology refers to the shape of a network’s wires; logical topology is the shape of the path the data follows as it moves through a network.
In Windows 7 and Windows Vista, most networking configurations are performed in the Network and Sharing Center.