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1. 04/13/2025 1
Computer Networks
By
K.SANDEEP KUMAR
(M.Sc. M.Tech)

2. NETWORKING
WINDOWS 2008 Server

3. NETWORKING
TOPICS :
 WHAT IS NETWORK?
 DIFFERENT BETWEEN NETWORK &
NETWORKING
 BENEFITS OF NETWORKING
 TYPES OF NETWORKS
 NETWORK MODELS
 NETWORK TOPOLOGIES
 COMMUNICATION MEDIA
 NETWORKING DEVICES
 OSI MODEL
 PROTOCOLS

4. WHAT IS NETWORK?
 A Network is collection of computers connected
together.
(or)
 A Network consists of two or more computers that are
linked in order to share resources such as printers, CD-
ROMs, files & folders.

5. NETWORK vs NETWORKING
Network:-
Is a collection of computers connected together.
Networking:-
Is a process of communication between the
interconnected computers.

6. Systems connected together Process of communication b/w
the interconnected systems.

7. BENEFITS OF NETWORKING
 Speed: Sharing and transferring files within Networks can be done through
process rate of @ 1Gbps which saves our time.
 Security: We can secure confidential, sensitive files and programs in our
network with password protected. By restricting access to Unauthorized users.
 Resource Sharing: Resources such as printers, modems, Drives can be
shared.
 Flexible Access: We can access the files from computers throughout our
organization / firm.
 Electronic mails: E-mail on a network can enable the users to communicate
and sending information formally.

8. TYPES OF NETWORKS
The Networks are differentiated as,
1.LAN(Local Area Network)
2.MAN(Metropolitan Area Network)
3.WAN(Wide Area Network)
4.CAN(Campus Area Network)

9. LAN:-
A network is said to be Local Area Network if it all
the systems are connected within the same geographical
area, expanding not more than a mile apart to other
computers.
SYSTEMS CONNECTED WITHIN THE ORGANIZATION

10. MAN:-
A network is said to be Metropolitan Area Network if the
systems are connected between the cities i.e connecting two or
more branches between the cities. OFC’s are used to link their
sites.
Router Fire ware Router Fire ware

11. CAN:-
A network is said to be Campus/Corporate Area Network, if it is
made up of interconnection of LAN’s within the limited geographical
area.CAN covers larger area than a LAN.
Systems connected b/w the LAN’s within a campus.
Building-1
Building-2
Building-3
LAN3
LAN2
LAN1

12. WAN:-
The network which covers or connects larger
geographical area such as countries London, UK, India etc
is said to be called as Wide Area Network.
Web
server
DC,
DNS
WAN
Router
Router
Switch
Switch

13. NETWORK MODELS
There are two types of network models:
1) Work-Group Model
2) Domain Model
Work-Group Model:-
Is also called as Peer-Peer network. It is a collection of computers connected together to
share the resources without any centralized administration where each user administers
their own computer.
-There is no dedicated server.
-There is no hierarchy among the computers.
-No administrator required.
-Is less expensive.

14. Domain Model:-
In this model there is dedicated server which is optimized to accept
the service requests from the network clients and sending the data as per
the client request. So, it is also called as Server-Based/Client-Server
Network.
-It provides centralized administration.
-It manages the security credentials.
-It can supports more number of clients which are in different
locations.
Server
The server is a central system in a network that serves the specific
requests from all the network clients.
Client
A Client is a computer which uses the resources of the server in
which the client sends the request to the server and the server
responds to the client’s request on security basis.

15. NETWORK TOPOLOGIES
Topology:
The way of cabling is called a topology. So, network
topology refers to the physical arrangement of a network where all
the devices are interconnected to communicate on the network.
The different types of topologies are:
 BUS TOPOLOGY
 RING TOPOLOGY
 STAR TOPOLOGY
 MESH TOPOLOGY
 HYBRID TOPOLOGY

16. Bus Topology:
The way of cabling held in this topology is single
cable where multiple computers and network devices are
connected in a single line. It is shown as,
Terminator Terminator

17. Ring Topology:-
In this topology, all the systems are connected to one another
forming a large circle in a closed loop.
-If any one station is down, the entire ring will get disturbed.
-In this network , it uses a special type of device called Media
Access Control which receives data through one port and
transmits data through another port.

18. Star Topology:-
In this topology each system is connected to a centralized network
device i.e. Hub, Switch. This is the most common network setup where the
central device joins all the different nodes together and controls the
communication b/w the systems on network.
-Easy to implement and expands our network.
-Security can be implemented in the switch used.
File
server
Network Printer
Centralized Device Hub/Switch
Clients
Clients

19. Mesh Topology:-
In this topology each of the systems and network devices are
interconnected with one another in a network for the data transmission.
-If one of the connection breaks, still the network will operate .
-A high-speed exchange of information is possible b/w the source
and destination.
-This type of topology is mainly used in Defense.
-It has a complex physical layout.

20. Hybrid Topology:-
The Hybrid topology is a combination of multiple
topologies into one large topology.
-One of the combination is Star Bus topology.
-Another combination can be Star Ring topology.
STAR BUS TOPOLOGY
STAR RING TOPAOLOGY

21. COMMUNICATION MEDIA
 The communication media is nothing but what type of cables we are
using to make communication possible in the network architecture.
 And the cable is the medium through which information usually
moves from one network device to another device.
 The type of cable can be chosen for a network is related to the
network’s topology, protocol and area covered to build the network.
 Depending on the cabling system we have different types of cabling
standards.
 In order to transfer data from one system to another through network
medium we have different communication media cables.
 And we also have the media connectors which is a physical
 device, helps for data transfer through the communication
 media cable.

22. CABLING STANDARDS
 10BaseT
 10BaseFL
 100BaseT
 100BaseTX
 100BaseFX
 100BaseT4
 1000BaseT
 1000BaseCX
 1000BaseSX
 1000BaseLX
 10GBaseSR
 10GBaseLR
 10GBaseER
The different types of cabling standards are:

23. TYPES OF MEDIA CABLES
The different types of media cable are:
 Twisted Pair
 Co-axial
 Fiber optical
Twisted Pair:-
This is one of the type of transmission media consists of color coded
pairs of two shielded or unshielded insulated copper wires in a spiral
pattern.
-The spiral pattern included minimizes crosstalk in the network.
-It is lighter, thinner and more flexible.
-It is inexpensive.

24. -There are two varieties of twisted pair cabling. They are:
1)Unshielded Twisted Pair(UTP).
2)Shielded Twisted Pair(STP).
UNSHIELDED TWISTED PAIR:-
-UTP cabling consists of two unshielded wires twisted around each
other that contain no shielding.
-The standard connector used is RJ-45 connector.
-It is commonly used in telephone wires and also in computer
networking.

25. UTP CATEGORIES:
• Category 1  only voice communication(telephone calls), transmits 1Mbps.
• Category 2  Modern Networks, Local calls, transmits 4Mbps.
• Category 3  used for 10Mbps Ethernet, 4Mbps Token Ring networks.
• Category 4  used for 16Mps Token Ring, 10Mbps Ethernet networks.
• Category 5  transmit data @ 100Mbps for LAN networks.
• Category 5e  carry additional voice and video conversations.
• Category 6  transmits data @ 1Gbps for Gigabit Ethernet.

26. SHIELDED TWISTED PAIR:-
In STP the twisted pairs are in a shield with electrically grounded
woven copper mesh separating them from cable’s outer sheet.
-This shielding is to provide resistance to external electromagnetic
interference(EMI).
-It prevents crosstalk.

27. CO-AXIAL CABLE:-
This is a primary type of cabling used mostly by the cable
television industry and also used for computer networks.
-It is expensive and also carry additional data like voice, video with
the
help of BNC which is a connector used for data transfer in co-axial
cabling.
Where BNC Bayonet Neill Conector

28. Fiber Optic cable:-
This is the standard cable used for connecting networks
between buildings as it is good for high-speed, high capacity data
transmission.
This Fiber optic cable has been classified into two types:
1)Single-mode.
2)Multi-mode.

29. TYPES OF MEDIA CONNECTORS
The different types of media connectors are:
RJ-11
RJ-45
SC connector
LC connector
BNC

30. As of our network, the twisted pair cables requires a special tool
called as crimper and RJ-45 connector. And this crimping has two types
of cabling, they are:
1.Straight-through Cable.
2.Cross-over cable.
1.Straight-through cabling:- Used to connect unlike devices.
-PC to Switch or Hub
-Router to switch or hub
2.Cross-over cabling:-Used to connect like devices.
-Switch to Switch
-PC to PC
-Hub to Hub

31. STRAIGHT-THROUGH CABLING COLOR
CODING:-
Orange white Orange white
Orange Orange
Green white Green white
Blue Blue
Blue white Blue white
Green Green
Brown white Brown white
Brown Brown

32. CROSS-OVER CABLING COLOR CODING:-
Orange white Green white
Orange Green
Green white Orange white
Blue Blue
Blue white Blue white
Green Orange
Brown white Brown white
Brown Brown

33. NETWORKING DEVICES
 Networking devices are also called as Communication
devices.
 Communication Devices are useful to provide
communication among the systems which are connected in
the network.
 Communication devices are helpful to expand our network.
Communication Devices are of two types. They are:
1)Intelligent Devices.
2)Non-Intelligent Devices.

34. COMMUNICATION DEVICES
Non-Intelligent Intelligent
1)HUBS 1)SWITCHES
2)REPEATERS 2)ROUTERS
3)BRIDGES

35. Non-Intelligent Devices
HUBS:-
Hub is a centralized device used for communication b/w the
computers interconnected.
The main disadvantage of a Hub is, when we want to
transfer some data from one system to another system & if our
N/W has 30 systems the data packet instead of being sent only
to the destination system, it is being send to all the systems in
the network i.e Hub allows broadcasting.

36. REPEATERS:-
Repeaters are used for boosting up the signals. If
two computers are at a 2 km distance and we need to
make the communication possible, as we having the
cable of 1½ km. In such case we will connect the
remaining ½ km cable with the help of repeaters.

37. INTELLIGENT DEVICES
SWITCHES:-
It is an advanced version and the main role of
switch is unicasting. The data packets are transmitted
directly to the target computer.
Switch maintains a table called MIT(Mac
Information Table)which acts like a index. This table
contains port. no, IP Address and MAC Address.

38. ROUTERS:-
Router is a device which connects two different networks. In
other cases connecting of Class A network with Class C network.
A router forwards packets across multiple networks through the
most optimal path. It performs the role of a post-man.
Router front panel Router-Back panel

39. BRIDGES:-
Bridge is a physical units with two ports.
- Bridges reduce the amount of traffic on a LAN by dividing it into two
segments.
- Bridges operate at the data link layer (Layer 2) of the OSI model.
- Bridges inspect incoming traffic and decide whether to forward or discard it.

40. OSI MODEL
 The Open System Interconnection Model was
developed by ISO which defines the networking
framework for implementing protocols.
 The OSI Model is an architecture which divides the
network communication into seven layers.

41. SEVEN LAYERS OF OSI MODEL
 Application Layer
 Presentation Layer
 Session Layer
 Transport Layer
 Network Layer
 Data Link Layer
 Physical Layer

42. Application
Presentation
Session
Transport
Network
Data Link
Physical
 HTTP, SMTP, FTP, TELNET.
 Data Conversion, Data compression, Data Encryption
 NFT, SQL, RPC, ASP
 TCP,UDP
 IP, BGP, OSPF
 MAC, L2TP, PPP
 Sends and receives the bits acts as a physical medium.

43. PROTOCOLS
 Protocol:- It is defined as the standard set of rules.
- It is a combination of logical and physical address.
- There are two types of protocols. They are:
1)Open protocol - Open to all TCP/IP.
2)Vendor Specific protocol - Vendor will specify the
protocol, dependent on the platform.
- The IP address is called as the Logical address.
- The MAC address is called as the Physical address.

44. IP Address:-
IP address is also called as 32-bit address which
contains 4 octets. A single octet contains 8-bits. It can be
written as,
w.x.y.z
MAC Address:-
MAC Address is the address burnt in the NIC card by
the manufacturer. It contains 48-bits in the form of
hexadecimal, which determines the physical location of a
system. It can be written as,
MM-MM-MM-SS-SS-SS

45.  Commands to Know your system IP Address and
MAC Address
 ipconfig
 ipconfig/all
 getmac
 getmac - s “system name”