Course Code: CS-301 Course Title: Introduction to Computing. Degree: BS (SE, CS, BIO) Contents of this chapter: Basic information about computer networks, types of computer networks. Other contents include: 1. List four major benefits of connecting computers to form a network. 2. Define the terms LAN, WAN, and MAN. 3. List the three types of networks. 4. Name the three physical topologies used to build networks.

1. Chapter 7
Networks

2. Learning Objectives:

List four major benefits of connecting computers to form a network.

Define the terms LAN, WAN, and MAN.

List the three types of networks.

Name the three physical topologies used to build networks.

3. Benefits of a Network:

Allows simultaneous access to critical
programs and data.

Allows people to share peripheral
devices, such as printers and scanners.

Streamlines personal communication
with email.

Makes the backup process easier.

4. Networking in a word: efficiency
SHARED DATA, PROGRAMS AND BACKUPS

5. Network Setup:
• LAN (Local Area Network)
• WAN (Wide Area Network)
• MAN (Metropolitan Area Network)

6. Local Area Network
LAN
• A network of computers located relatively near
each other and connected by a cable.

7. Wide Area Network
WAN
• Two or more LANs connected together, generally
across a wide geographical area using high-speed or
dedicated telephone line.

9. Metropolitan Area Network
MAN
• Similar to a WAN network but is confined to a
single city or metropolitan area.

11. Node - individual computers attached to a
network.

12. Intranet:

13. Extranets:

14. Network Types:
 Server
Network
 Peer-to-Peer
Network

15. Server Network:
• File Server
– used to store and forward (send) files from and
to computers (nodes) on the network.
• Client/Server
– individual computers (nodes) share the
processing and storage workload with a central
server.

16. Peer-to-Peer Network:
• Simple Peer-to-Peer
– all nodes on the network have equal
relationship to all others, and all have similar
types of software.
• Distributed Computing
– enables users to draw on the processing power
of other computers in the network.

17. Topology - the physical layout of the cables that
connect the nodes of the network.

18. Network Topologies:
• Bus topology
• Star topology
• Ring topology

19. Bus topology - a single node to which all the network
nodes and peripheral devices are attached.

20. Bus: a single path connects all devices.
BUS
A broken path can bring down all connected devices.

21. Star topology - places a hub in the center of the
network nodes. Groups of data are routed through the
central hub to their destinations.

22. Star: the hub is in the center of the network nodes.
The entire network goes down only if the hub is lost.

23. Ring topology - connects the nodes of the network in
a circular chain in which each node is connected to the
next.

24. Ring: each node is chained to the next.
If a connection is lost, the entire network goes down.

25. Network Media - refers to the wires, cables, and other
means by which data travels from its source to its
destination.

26. Network Media:
• Twisted-pair wire
• Coaxial cable
• Fiber-optic cable
• Wireless links

27. Twisted-pair Cable:

28. Coaxial Cable:

29. Fiber-optic Cable:

30. Wireless media:

31. Protocols

32. Network Protocol - a set of standards for
communication.
• TCP/IP
• IPX/SPX
• NetBEUI

33. TCP/IP

34. IPX/SPX
NetBEUI

35. Network Technologies:
•
•
•
•
Ethernet
Fast Ethernet
Token Ring
ARCnet

36. Ethernet:
 Ethernet is the most widely-installed local area network ( LAN)
technology. Specified in a standard, IEEE 802.3, Ethernet was
originally developed by Xerox from an earlier specification
called Alohanet (for the Palo Alto Research Center Aloha network)
and then developed further by Xerox, DEC, and Intel.
 An Ethernet LAN typically uses coaxial cable or special grades
of twisted pair wires. Ethernet is also used in wireless LANs.
 The most commonly installed Ethernet systems are called 10BASET and provide transmission speeds up to 10 Mbps.
 Devices are connected to the cable and compete for access using a
Carrier Sense Multiple Access with Collision Detection (CSMA/CD )
protocol.

37. Fats Ethernet:
Fast Ethernet is a local area network (LAN) transmission
standard that provides a data rate of 100 megabits per
second (referred to as "100BASE-T"). Workstations with
existing 10 megabit per second (10BASE-T) Ethernet
Card can be connected to a Fast Ethernet network. (The 100
megabits per second is a shared data rate; input to each
workstation is constrained by the 10 Mbps card.)

38. Gigabit Ethernet:
Gigabit Ethernet, a transmission technology based on
the Ethernet frame format and protocol used in local
area networks (LANs), provides a data rate of 1 billion
bits per second (one gigabit). Gigabit Ethernet is
defined in the IEEE 802.3 standard and is currently
being used as the backbone in many enterprise
networks.

39. Token Ring:
A Token Ring network is a local area network (LAN) in which all
computers are connected in a ring or star topology and a bit- or
token-passing scheme is used in order to prevent the collision
of data between two computers that want to send messages at
the same time. The Token Ring protocol is the second most
widely-used protocol on local area networks after Ethernet.

40. ARCNET
 ARCNET is a widely-installed local area network (LAN) technology that uses
a token-bus scheme for managing line sharing among the workstations and
other devices connected on the LAN.
 The LAN server continuously circulates empty message frames on a bus(a
line in which every message goes through every device on the line and a
device uses only those with its address).
 When a device wants to send a message, it inserts a "token" (this can be as
simple as setting a token bit to 1) in an empty frame in which it also inserts
the message. When the destination device or LAN server reads the
message, it resets the token to 0 so that the frame can be reused by any
other device.
 The scheme is very efficient when traffic increases since all devices are
afforded the same opportunity to use the shared network.

41. Network Operating System (NOS) - the group of
programs that manages the resources on the network.

42. Network Operating System Software:
•
•
•
•
Microsoft Windows NT Server
Banyan VINES
AppleShare
Artisoft LANtastic

43. Modem - (short for modulator-demodulator).
Used to translate digital signals into analog
signals that can travel over standard phone
lines.

44. Modem

45. Digital Phone Lines:
 ISDN
 T1
 T3
 ATM

46. ISDN(Integrated Services Digital Network)

ISDN (Integrated Services Digital Network) is a standard for
digital transmission over ordinary telephone copper wire as
well as over other media.

Home and business users who install an ISDN adapter (in place
of a telephone modem) receive Web pages at up to
128 Kbps compared with the maximum 56 Kbps rate of a
modem connection.

ISDN requires adapters at both ends of the transmission so
your access provider also needs an ISDN adapter.

In many areas where DSL and cable modem service are now
offered, ISDN is no longer as popular an option as it was
formerly.

47. T1

48. Multimedia Network - a network that enables
artists to store, retrieve, and share data with other
users.