Question

Explain Star Topology with a diagram.

Hint:

Star topology is the most widely used network topology in modern local area networks (LANs). It utilizes twisted-pair Ethernet cables (with RJ45 connectors) connected to a central active switch to manage traffic efficiently and prevent collisions.

Answer 1

Step 1: Core Operating Concept of Star Topology:
In a physical Star Topology, all client computers, workstations, and peripheral network nodes are connected directly to a central, common coupling device—typically an active Switch or a passive Hub—using individual dedicated point-to-point cables. Unlike bus or ring topologies, there is no direct physical connection or data path between individual client nodes. All communications, data packets, or files sent from one node to another must travel through the central switch, which acts as a central distribution junction.

Step 2: Detailed Architectural Layout and Signal Flow Path:
Since drawing the diagram directly is not required, below is a complete, detailed visual and signal flow breakdown of the topology:

• Physical Arrangement: The physical layout resembles a star: the central switch/hub sits at the geographic center, and dedicated radial links (ethernet cables) extend outward to each independent workstation.
• Signal Flow Path: When Workstation A wishes to transmit a data frame to Workstation B, the packet travels from Workstation A's NIC through its dedicated line to the central switch. The switch reads the destination MAC address, checks its MAC address table, and forwards the packet exclusively out of the port connected to Workstation B.

Step 3: Key Advantages and Disadvantages:
This topology has several distinct performance characteristics:

• Advantages:
  • High Fault Tolerance: If an individual cable or network interface card (NIC) fails, only that specific node is disconnected from the network. The rest of the network nodes continue to communicate without any interruption.
  • Easy Scalability: Adding or removing a device is incredibly simple; you just plug or unplug an ethernet cable from the central switch, without disrupting active users.
• Disadvantages:
  • Central Device Dependency: If the central switch/hub experiences a hardware crash or power failure, the entire network fails immediately (representing a Single Point of Failure).
  • High Cabling Cost: It requires a separate cable for every single device connected to the network, which significantly increases installation costs compared to a simple bus topology.