This is my third lecture for my basic computer class

1. NETWORKING
DEPARTMENT OF INFORMATION SYSTEMS
COLLEGE OF COMPUTER STUDIES
XAVIER UNIVERSITY – ATENEO DE CAGAYAN

2. Data Communications and
Networking

3. What is a Network?
• Defined as two or more computing devices connected
together in such a way that they can share resources
• Resources:
• files
• folders
• printers
• disk drives
• etc.
3

4. What is a Network?
• A collection of computers or other hardware devices that are
connected together, either physically or logically, using special
hardware and software, to allow them to exchange information and
cooperate
4

5. What is Networking?
• Term that describes the process involved in designing,
implementing, upgrading, managing, and otherwise working with
networks and network technologies
5

6. Advantages of Networking
• Connectivity and Communication
• Data Sharing
• Hardware Sharing
• Internet Access
• Internet Access Sharing
• Data Security and Management
• Performance Enhancement and Balancing
• Entertainment
6

7. Disadvantages of Networking
• Cost of setup
• Management and administration costs
• Undesirable sharing
• Illegal or undesirable behavior
• Data security concerns
7

8. Basic Components of a Network
• Server
• core component of the network
• provides link to the resources necessary to perform any task
• Client
• requests and receives information over the network client
• depends primarily on central server for processing activities
• Circuit
• cables, ports and other devices that connect the server and the client
computers
8

9. Network Interface Card (NIC)
• Circuit board that fits in one of the computer’s internal expansion
slots
• Contains circuitry that handles sending, receiving, and error
checking of transmitted data
9

10. Key Points in Networking
• Important characteristics that influence transmission technologies
and communication protocols
• size
• shape
• Networks are classified according to area over which they extend
• Size and extension depend on number of nodes that need to
communicate, and where these nodes are in relation to each other
10

11. Network Classifications
• PAN (personal area
network)
• refer to the
interconnection of
personal digital
devices or consumer
electronics w/n the
range of 30ft (10m)
and without the use
of wires or cables
11

12. Network Classifications
• LAN (local area network)
• data communications
network the connects
personal computers within a
very limited geographical
area
• school computer labs
• home networks
12

13. Network Classifications
• MAN (metropolitan
area network)
• public high-speed
network capable of
voice and data
transmission within
the range of 50mi
(80km)
• ISPs
• small cable TV
companies
• local telephone
companies
13

14. Network Classifications
• WAN (wide area
network)
• covers large
geographical area
and usually consists
of smaller networks
• nationwide banks
• large cable TV
companies
• multi-location
superstores
• internet
14

15. Network Topologies
• Architectural “drawings” to show the overall physical configuration
for a given communications system
• Indicates the access methods and governs the rules that are used to
design and implement the communication system
15

16. Network Topologies
• Bus topology
• Single electrical circuit
to which all devices in
network are connected
16

17. Network Topologies
• Star topology
• individual computers are
connected to a central
device such as a hub or a
switch
17

18. Network Topologies
• Ring topology
• a collection of separate point-to-
point links arranged to make a
ring
• each nodes NIC has one input and
one output connection
• so each node has two links
18

19. Communications Model
19
Source
Transmitter Receiver
Destination
Source
System
Destination
System
Transmission
System

20. Communications Model
20
Personal
Computer
Modem
Broadband
Connection
Modem
Server

21. NETWORK TOPOLOGY CASE STUDY:
This will serve as your ACTIVITY 2.
SEARCH FOR ONE (1) CASE STUDY IN EITHER OF THE FOLLOWING
TOPOLOGY ARE PRESENT:
* BUS TOPOLOGY * STAR TOPOLOGY * RING TOPOLOGY
Take note what are the advantages and disadvantages of your chosen
topology based on your case study. Put it in Word, then save as
“<Lastname>_Activity2”
Be ready! I will call some students to present their research

22. Network Building Blocks
COLLEGE OF COMPUTER STUDIES
XAVIER UNIVERSITY – ATENEO DE CAGAYAN

23. Network Devices
• Sometimes referred to as a network appliance
• Any electronic device that broadcasts network data, boosts signals,
or routes data to its destination

24. Network Devices
• Node
• Each connection point on a network
• Usually contains:
• Computer
• Networked peripheral
• Network device
• Workstation
• Personal computer connected to a network

25. Network Devices
• Network Interface Card (NIC)
• Circuitry to connect to LAN
• Sometimes built-in in some personal computers
• Can be added to an expansion slot or USB port
• Networked peripheral
• Any device that contains network circuitry to directly connect to a network
• Examples: printers, scanners, storage devices

26. Network Devices
• Router
• Central
distribution point
for getting data to
its destination

27. Network Devices
• Hubs
• Extends a wired network by adding additional ports

28. Network Devices
• Switches
• Intelligently facilitates communication among multiple devices on a network

29. Network Devices
• Gateways
• Joins two different types of networks, such as your home network and the
Internet

30. Network Devices
• Bridges
• Connects two similar networks

31. Network Devices
• Wireless access points
• Allows wireless devices to connect to a wired network

32. Network Devices
• Repeaters
• Extends the range of a network by restoring signals to maximum strength
and retransmitting them

33. Sample LAN Setup

34. Network Links
• Links
• Communications channel
• Physical path or a frequency for signal transmissions
• Wired – cables
• Cat 5 or Cat 6 (max length of 100m)
• RJ45 connector

35. Network Links
• Bandwidth
• Transmission capacity of communications channel
• High-bandwidth (broadband) can carry more data than low-bandwidth
(narrowband)
• Digital bandwidth is measured in bits per second (bps)
• Analog bandwidth is measured in hertz (Hz)

36. Communications Protocol
• Protocol
• Set of rules for interacting and negotiating
• Communications protocol
• Set of rules for efficiently transmitting data from one network node to
another
• TCP/IP
• Transmission Control Protocol/Internet Protocol
• Internet data support and standards for LANs

37. Communications Protocol
• Aspects of network communications that communications protocol
handles
• Dividing messages into packets
• Affixing addresses to packets
• Initiating transmission
• Regulating flow of data
• Checking for transmissions errors
• Acknowledging receipt of transmitted data

38. Communications Protocol
• Packets
• A parcel of data that is sent across a computer network
• Contains:
• Address of sender
• Destination address
• Sequence number
• Some data

39. Communications Protocol
• Data are broken down into packets and reassembled in the destination
according to sequence number

40. Communications Protocol
• Circuit switching
• Used by some technologies like telephone system
• Dedicated private link between one telephone to another telephone for the
duration of the call
• Inefficient

41. Communications Protocol
• Packet switching
• Divides message into several packets that can be routed independently to
their destination
• Messages divided into equal-size packets are easier to handle than an
assortment of small, medium, large, and huge files
• Packets are shipped over the circuit on a first-come, first-served basis

42. Communications Protocol

43. Communications Protocol

44. Communications Protocol
• Routing of packets
• Each packet contains the address of the destination device
• Communications protocol specify the proper format of addresses
• Two commonly used addresses:
• MAC address
• IP address

45. Communications Protocol
• MAC address
• Media Access Control address
• Unique number assigned to a network interface card when it is
manufactured
• Used in low-level network functions and can also be employed to establish
network security

46. Communications Protocol
• IP address
• Internet Protocol address
• Series of numbers used to identify a network device (computers, servers,
peripherals, and devices)
• Originally used in the internet but used in LANs
• Example: 204.127.129.1
• Four groups of numbers separated by period
• Octet (eight bits in binary)

47. Communications Protocol
• IP address
• Assigned by ISPs or system managers
• Sometimes assigned by DHCP
• Dynamic Host Configuration Protocol
• Automatically distributes IP addresses
• Computers send a query to the network device acting as the DHCP server
• IP address is good for that session only