Overview of Network Topologies

Network topology refers to the physical or logical arrangement of devices in a network. Here's a quick look at the basic types:

1. Bus Topology

All devices share a single communication line (a backbone cable).

Simple and cost-effective, but if the backbone fails, the entire network is down.

Example: Early Ethernet networks.

2. Ring Topology

Devices form a circular path, where data flows in one direction.

Good for small networks, but one break affects the whole system.

Example: Token Ring networks.

3. Star Topology

All devices are connected to a central hub or switch.

Easy to manage and expand. If one cable fails, only that device is affected.

Example: Modern home/office LANs.

4. Mesh Topology

Every device is connected to every other device.

High redundancy and fault tolerance, but very expensive.

Example: Used in critical networks like military or data centers.

5. Hybrid Topology

Combination of two or more topologies.

Flexible and scalable based on need.

Example: Star-Bus or Star-Ring combinations.

Network Simulator: Cisco Packet Tracer

What is Packet Tracer?

It’s a simulation tool developed by Cisco that helps you practice networking without needing physical hardware.

Installation & User Interface

Download from Cisco’s official site after creating a free NetAcad account.

Interface Overview:

Device panel – routers, switches, PCs

Workspace – drag and drop devices

Connections tab – choose cables

CLI & GUI tabs – configure your devices

Deploy Devices and Cables

Steps:

1. Drag devices (like routers, switches, PCs) to the workspace

2. Click on the lightning icon → choose appropriate cable

3. Connect interfaces (e.g., PC to Switch using copper straight-through)

GUI and CLI Configuration

GUI (Graphical User Interface):

Click device → Desktop tab → IP Configuration → set IP, Subnet Mask, Gateway

CLI (Command Line Interface):

Access Router or Switch

Basic commands:

enable

configure terminal

interface FastEthernet0/0

ip address 192.168.1.1 255.255.255.0

no shutdown

Configure End Devices (PCs)

Go to PC → Desktop → IP Configuration

Enter:

IP Address: 192.168.1.2

Subnet Mask: 255.255.255.0

Default Gateway: 192.168.1.1

Now try pinging the router using the Command Prompt on the PC:

ping 192.168.1.1

If successful, your basic network is up.