1. Computer Networks: Hands On Experience
Pongpisit Wuttidittachotti, Ph.D.
Faculty of Information Technology
King Mongkut's University of Technology North Bangkok (KMUTNB)

2. Outline What is a Network? Network Components Putting It all Together
LAN & WAN
LAB #1: Testing the network connectivity
LAB #2: Connect 2 computers using a cable

3. What is a Network?
A Network is two or more devices connected to a common medium.

4. Network Components All networks have 4 basic elements in common:
Devices on the network that exchange messages.
Rules (protocols) to govern the handling of the message.
Messages that travel from one device to another.
Medium that is used to interconnect devices and can transport the messages from one device to another.

5. Devices on a network – Common Symbols

6. Messages take many forms.

7. Media on a network can be varied.
Guided
(wired)
Twisted Pair Cable
Coaxial Cable
Fiber Optic Cable
Unguided
(wireless)
AIR WATER

8. Rules on a network seem almost endless – but they’re not.
Rules (Protocols)
Rules on a network seem almost endless – but they’re not.
Other Application Protocols:
DNS, DHCP, FTP
Some Other Protocols:
TCP/IP Protocol Suite, Ethernet, Routing Protocols

9. Communications – What is it?
We establish rules, or protocols, for communicating with each other:
Identify the sender and receiver.
Agree on the method.
Common language.
Speed and delivery of the message.
Confirmation that the message was received.
Communications between individuals is successful if the meaning of the received message is the same as the meaning of the message that was sent.

10. Putting It all Together
1. Converted to Binary.
2. NIC generates signals.
3. Passed among LAN devices.
4. Exit the local area (router).

11. Putting It all Together
The many interconnected devices worldwide are often represented by a cloud.
5. Bits are transmitted to devices that interconnect the networks.

12. Putting It all Together
6. Passed among local devices at the destination.
7. The destination device converts the bits into human readable form.

13. Putting It all Together
At each of these steps, there are protocols that define the rules for device communication. 5 7 6 1 2 3 4

14. LAN & WAN

15. Local Area Networks
An individual network usually spans a single geographical area, providing services and applications to people within a common organizational structure, such as a single business, campus or region.

16. Wide Area Networks
Networks that connect LANs in geographically separated locations. Usually implemented with leased connections through a telecommunications service provider (TSP) network.
A TSP traditionally transports voice and data on different networks. Now, providers are offering converged network services.
HDLC, PPP, T1, DS3, OC3, ISDN, Frame Relay

17. LAB #1: Testing the network connectivity
Ping
Traceroute (tracert)

18. Testing the Network Layer

19. “ipconfig” command ipconfig is a commmand line utility.
This utility allows you to get the IP address information of a Windows computer.

20. Testing the Network Layer
C:>ping Verifies that the local IP configuration is correct.
C:>ping Verifies that the host can reach the gateway.

21. Testing the Network Layer
C:>ping

22. Testing the Network Layer

23. LAB #2: Connect 2 computers using a cable

24. What do you need to know?
IPv4
Cable types

25. Anatomy of an IPv4 Address
Each device on a network must be uniquely identified at the Network layer.
For IPv4, a 32 bit source and destination address is contained in each packet.

26. Anatomy of an IPv4 Address
32 bit Binary String
Divided into OCTETS
Expressed in DOTTED DECIMAL NOTATION
Devices use binary logic and work with strings of binary numbers. For us, the decimal equivalent is much easier to use and remember.

27. Anatomy of an IPv4 Address
1.2
2.2
1.1
2.1
1.3
3.1
3.2
To identify a path or "route" through a network, the address must be composed of two parts:
Network portion
Host portion

28. Anatomy of an IPv4 Address
IP Address
192.
168. 1. 2
Binary IP Address
Network Portion:
Some portion of the high-order bits represents the network address.
We define a network as a group of hosts that have identical bit patterns in the network address portion of their addresses.

29. Anatomy of an IPv4 Address
IP Address
192.
168. 1. 2
Binary IP Address
Host Portion:
There are a variable number of bits that are called the host portion of the address.
The number of bits used in this host portion determines the number of hosts that we can have within the network.

30. Binary to Decimal Conversion
In all number systems, the digits start with 0.
A Base-n number system has n number of digits:
Decimal:
Base-10 has 10 digits
9, 8, 7, 6, 5, 4, 3, 2, 1, 0
Binary:
Base-2 has 2 digits
1, 0
Hexadecimal:
Base-16 has 16 digits
F, E, D, C, B, A, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0

31. Binary to Decimal Conversion
Positional Notation (Decimal Number System):
Means that a digit represents different values depending on the position it occupies.
The value that a digit represents is that value multiplied by the power of the base according to the position the digit occupies. 1 2 3
Position
100
101
102
103
Base 1 10
100
1,000
Value 4 3 1 2
String
(2x103) + (1x102) + (3x101) + (4x100) = 2,134

32. Binary to Decimal Conversion
Computers react only to electrical impulses.
They work with and store data using electronic switches that are either on (1) or off (0).
They can only understand and use data that is in this two state format.
These 1's and 0's are called binary digits or bits.

33. Binary to Decimal Conversion
Positional Notation (Binary Number System):
Means that a digit represents different values depending on the position it occupies.
The value that a digit represents is that value multiplied by the power of the base according to the position the digit occupies. 20 21 22 23 24 25 26 27
Base 1 2 3 4 5 6 7
Position 1 2 4 8 16 32 64
128
Value 1
String
(1x26) + (1x25) + (1x23) + (1x22) = 108

34. Binary to Decimal Conversion20 21 22 23 24 25 26 27
Base 1 2 3 4 5 6 7
Position 1 2 4 8 16 32 64
128
Value
String 1
String 1
String 1
String
Range: 0 to 255

35. Binary to Decimal Conversion
IP Address:
201 17 29 4
IP Address: 20 21 22 23 24 25 26 27 1 2 4 8 16 32 64
128 1 1 1 1

36. Binary to Decimal Conversion27 26 25 24 23 22 21 20
Dec.
128 64 32 16 8 4 2 1 21 50
101
150
206

37. Managing Big Network

38. Managing Subnets

39. Different Network Size
Network Prefix # of Host Addresses Mask / / / / / / /

40. Straight-Through, crossover, rollover

41. Straight Through - Switch to a router Ethernet port
- Computer to switch
- Computer to hub

42. Crossover Cables Switch to switch Switch to hub Hub to hub
Router to router Ethernet port
Computer to computer
Computer to a router Ethernet port

43. Console Cable

44. Thank you for your attention

45. Reference
CCNA, St. Clair College in Windsor, Ontario.

46. Backup

47. LAB#3: Creating subnet Configure the 2 PCs to be in the same subnet
Try Pinging between the two PCs
Configure the 2 PCs to be in different subnet

48. IOS configuration Mode