Computer Networking

• Share resources from one computer to another.

• Create files and store them in one computer, access those

files from the other computer(s) connected over the network.

• Scalability increases the system performance by adding

more processors

• Security is the main characteristics of Computer network

where you can take necessary steps for protecting your data
from unauthorized access

Different Types of Networks

Local Area Network (LAN)

Metropolitan Area Network (MAN)

Wide Area Network (WAN)

Personal Area Network (PAN)

LAN

➢ It's a group of computers

which all belong to the same
organization.

➢ Data transfer speeds is up to

10 Mbps.

➢

A local area network can

reach as many as 100, or
even 1000, users.

LAN provides

two different

operating modes

1. Peer-to-peer network
2. Client/server network

MAN

➢The metropolitan area network (MAN) is designed to
extend over an entire city.
➢It may be a single network such as cable television
network available in many cities.
➢A MAN uses distributed queue dual bus.
➢Range: Within 100 km (a city).

Bus A

Bus B

MAN

WAN

PAN

•A PAN is a network that is used for communicating
among computers and computer devices (including
telephones) in close proximity of around a few meters
within a room.

• It can be used for communicating between the
devices themselves, or for connecting to a larger
network such as the internet.

• PAN’s can be wired or wireless.

Network Topologies

Topology
•Topology refers to the layout of connected
devices on a network.

•The most common shapes are:

• Star
• Ring
• Bus
• Tree
• Hybrid

Star Topology

•A star topology is also called a hub topology, or a
centralized topology.

•A traditional approach to connecting devices where all
transmitted data passed through a central controller.

•This topology make routing very easy since the central
controller is connected to all other hosts, and knows the path
to all hosts.

Star Topology

Star Topology

Ring Topology

•A ring topology is one where all hosts are
connected together in a closed loop.

Ring Topology

Ring Topology

•Data is passed around in packets and typically is
passed in one direction around the loop.

•The packet knows its Source and Destination hosts.

•It will loop from the Source, around to the Destination
host, which makes a copy of the packet, and the original
packet continues the loop back to the Source.

Ring Topology

Bus Topology

•A bus topology is one where all the sites are
connected to a single communications line (or bus)
running the length of the network.

Bus Topology

Bus Topology

•Hosts can send data from one host to another via
the bus, the message will usually be sent in both
directions, and will keep travelling until they reach
the End-Point Controllers.

•So if I want to send from Host 1 to Host 3.

Bus Topology

Bus Topology

•Some bus topologies only allow the packets to
travel in one direction until the reach the end-point
controller, who can send it back in the opposite
direction if the destination hasn’t received the packet
yet.

Bus Topology

Tree Topology

•A tree topology is a combination of bus topologies.
The cables branch out, and there are no closed
loops.

•The tree begins at a Head End Controllers and
each branch terminates at an End Point Controller.

Tree
Topology

Tree Topology

•A packet from one node to another will be sent
down all branches, and will be absorbed by the End
Point Controllers of the branches that does not
contain the Destination host.

•Let’s do an example of going from Host 4 to Host
5.

Tree
Topology

Hybrid Topology

•A hybrid topology is one which combines any two
of the previous topologies.

STAR + BUS

Hybrid Topology

Hybrid Topology

Hybrid Topology

RING + BUS

Hybrid Topology

Hybrid Topology

Hybrid Topology

Switc

h

Hybrid Topology

STAR + RING

Hybrid Topology

Hybrid Topology

Hybrid Topology

Switc

h

Network Architecture

Client Server Model

Peer to Peer Connection