Basics of Cisco Packet Tracer (Part 2) | Hub

Basics of Cisco Packet Tracer: Part Two

Introduction to Hubs

• The lecture focuses on the basics of Cisco Packet Tracer, specifically on hubs and their role in local area networks (LAN).

• Key outcomes include understanding what a hub is, simulating a LAN using a hub, and discussing the pros and cons of using hubs.

Understanding Hubs

• A hub operates at the physical layer (Layer 1) of the OSI model and is essential for setting up a local area network.

• Hubs have multiple ports; for example, a hub with 10 ports can connect 10 computers. Additional hubs can be connected to expand the network.

Topology and Functionality

• Networks formed using hubs typically follow star topology, where all devices connect to a central device like a hub or switch.

• When data arrives at one port of the hub, it is broadcasted to all other ports, allowing all devices on the LAN to receive the same packet regardless if they need it.

Working Principle of Hubs

• To connect devices to a hub, an Ethernet straight-through cable is used between each computer and the hub.

• The process involves sending data from one computer through its designated port on the hub, which then copies this data across all other ports.

Practical Demonstration Using Cisco Packet Tracer

• In Cisco Packet Tracer, users can create a LAN by selecting a hub and connecting multiple PCs via straight-through cables.

Assigning IP Addresses to PCs

Step-by-Step IP Assignment

• The process begins with assigning an IP address to the first PC, which is set to 10.10.10.1.

• The second PC receives the IP address 10.10.10.2, while the third and fourth PCs are assigned 10.10.10.3 and 10.10.10.4 respectively.

• The fifth computer is given the IP address 10.10.10.5, and the last computer is assigned 10.10.10.6.

• After all assignments, a check is performed on the third PC's IP configuration using ipconfig, confirming it as 10.10.10.3.

Testing Communication Between PCs

• A ping test is initiated from the third PC (IP: 10.10.10.3) to the sixth PC (IP: 10.10.10.6), resulting in successful communication.

Understanding Hub Functionality

Transitioning to Simulation Mode

• The demonstration shifts from real-time mode to simulation mode for better visualization of packet transmission.

Packet Transmission Process

• A packet is sent from one PC (source) to another (destination), illustrating how data travels through a hub.

• Upon receiving a packet, the hub forwards it to all connected ports; only the intended recipient accepts it while others reject it.

Acknowledgment Mechanism

• When acknowledgment is sent back from the destination computer, it follows a similar broadcasting pattern through the hub.

Pros and Cons of Hubs

Advantages of Using Hubs

• Hubs are cost-effective compared to switches, making them suitable for smaller networks where budget constraints exist.

Disadvantages of Hubs

• Major drawbacks include issues with broadcasting that can overwhelm larger networks due to excessive traffic.

• Hubs lack memory capabilities; they do not store information about received packets and operate in half-duplex mode—sending or receiving data but not both simultaneously.

Conclusion on Network Devices

• As technology advances, hubs are being replaced by switches due to their limitations in modern networking environments, emphasizing their declining relevance in contemporary setups.