OBJECTIVE:

o Describe various network topologies

o Discuss the role of network devices

o Understand Network Configuration Factors to deploy a new

network

1.0 NETWORK TOPOLOGIES

Physical layout of computers, cables and other components on the network

Also referred as: Physical Layout Design Diagram Map

1.1 Purpose of Network Topology

How computers communicate on the network

Different topology – Different communication method

1.2 Types of Network Topologies

Bus Star Ring

1.2.1 Bus

Terminals are connected in a row along a single cable

Single cable is also known as Trunk, Backbone or Segment

1.2.1.a How it works?

Sending host sends the data to all computers in network

Only that node accepts the data whose address matches the destination code

Only one computer can send data at one time

Network performance affects as number of nodes increases

If one computer fails it does not affect rest of the network

Terminators are installed at each end to absorb free signals (signal bouncing)

Network becomes down if one end is empty or cable is physically cut

1.2.2 Star

Terminals are connected by a cable segment to a central device

Central Device can be a HUB or Switch

1.2.2.a How it works?

Sending host sends the data to central device

Central Device sends the data to receiving host

If central device fails, the entire network becomes down

If one computer or one cable fails, it does not affect rest of the computers

1.2.3 Ring

Terminals are connected on a single circle of cable

No terminated ends

1.2.3.a How it works ?

Signals travel in a loop in one direction and pass through each computer

Each computer acts like a repeater unlike passive bus topology

Failure of one computer can impact the entire network

Ring topology use TOKEN PASS technology

2.0 NETWORK DEVICES

PURPOSE OF NETWORK DEVICES:

Regulate the speed at which network information travels

Manage flow of traffic, opening, closing and directing of traffic

Protect sensitive information

2.1 Network Interfaces

Network Interface Card (NIC) is a device used to connect computers, printers and other peripherals to a network

Sending NIC --- Parallel into serial form

Receiving NIC --- Serial into Parallel form

Speed is measured in bps

Each NIC has a unique MAC address

Each NIC is assigned an IP Address by Network Administrator

2.2 HUB

HUB stands for Hybrid Universal Bus

A small device gathers the signals from each individual device optionally amplifies, and sends the data to all other connected devices

All devices connected to a HUB share the bandwidth of network

More devices connected to a HUB, lower the network performance

12 or 24 ports available in standard HUB

Speed is measured in bps

2.3 Switch

Switch works exactly in the same way as HUB except:

It does not broadcast It does not interfere network bandwidth

8, 12, 24 Ports are usually available

Speed is measured in bps

Must be compatible with other network devices

2.4 Routers

Routers connect two or more networks of different design

Find the best path (route) to transmit data

Routers can be programmed to define traffic rules

Expertise are required to configure routers

2.5 Firewalls

A device (combination of hardware and software) that protects unauthorized access to a networkTypes of Firewalls

Packet Screening Firewalls Proxy Servers State full Inspection Proxies

3.0 NETWORK CONFIGURATION FACTORS

i. Choosing the Network Type / Utilization• Peer to Peer• Server Based Networking

ii. Choosing the Network Topology / Performance• Bus• Star• Ring

iii. Choosing the Communication Media / Performance• Physical Media• Wireless Media• Light Emitted Media

iv. Future Considerations / Flexibilityv. Costvi. Maintenance