Jawaharlal Nehru Technological University Hyderabad B.Tech III PRINCIPLES OF COMPUTER COMMUNICATIONS AND NETWORKS Previous Question Paper (November/December - 2020 - R16)

Network topology refers to the physical or logical arrangement of devices (nodes) and the connections (links) between them in a communication network. The choice of topology affects the network's performance, scalability, cost, and reliability.

The primary network topologies are:

• Bus Topology: All nodes are connected to a single central cable called the backbone or bus. Data is transmitted in both directions. It is simple and cost-effective for small networks, but the entire network fails if the main cable breaks.
• Star Topology: Every node is connected to a central hub or switch. Data passes through the central device before reaching the destination. It is easy to troubleshoot and add new devices, but the central hub represents a single point of failure.
• Ring Topology: Each node is connected to two other nodes, forming a continuous circular path. Data travels in one direction (unidirectional) or both (bidirectional). It prevents data collisions but is difficult to reconfigure, and a single node failure can disrupt the entire ring.
• Mesh Topology: Every node is connected to every other node in the network. This provides high redundancy and fault tolerance. In a full mesh, the number of links is calculated as
  n(n-1)/2
  , where n is the number of nodes. While highly reliable, it is expensive and complex to install.
• Tree Topology: A hierarchical structure where a root node connects to secondary nodes, which in turn connect to tertiary nodes. It is essentially a collection of star networks connected via a bus. It is ideal for large networks but depends heavily on the root node.
• Hybrid Topology: A combination of two or more different topologies (e.g., a star-bus or star-ring). It offers flexibility and can be tailored to specific organizational needs, though it is often more complex to manage and maintain.