In computer network topologies, which topology generally offers the highest reliability because every node is directly connected to many or all other nodes?

Introduction / Context:
Network topology describes the physical or logical layout of devices and links in a network. Reliability refers to the network's ability to continue functioning even when some links or nodes fail. Different topologies provide different levels of redundancy. This question asks you to identify which topology is generally considered the most reliable because of its high level of interconnection.

Given Data / Assumptions:

• We are considering common topologies: bus, star, ring, and mesh.
• Reliability is linked to redundancy in paths between nodes.
• Failure of a single cable or node should not easily isolate large parts of the network in a highly reliable design.
• A fully or highly connected mesh has multiple paths between devices.

Concept / Approach:
In a mesh topology, especially a full mesh, every node is connected directly to every other node. This creates many redundant paths. If one link fails, data can be rerouted through other nodes. As a result, mesh topologies are extremely reliable and fault-tolerant, though they are more expensive and complex to implement. By contrast, bus and ring topologies can have single points of failure, and star topologies depend heavily on the central hub or switch.

Step-by-Step Solution:
1. Consider a bus topology: a single backbone cable connects all devices. Failure of the backbone can bring down the entire network, so reliability is limited.2. In a ring topology, each device has two neighbours; if the ring is not dual or self-healing, a break can disrupt communication.3. In a star topology, all devices connect to a central hub or switch; if that central device fails, the whole network can be affected.4. In a mesh topology, devices have multiple interconnections, providing several alternate paths; failures in a few links or nodes usually do not isolate others.5. Therefore, a mesh topology is generally regarded as offering the highest reliability.6. Among the options, Mesh (Option A) is the correct choice.

Verification / Alternative check:
High-availability networks for critical infrastructure, such as backbone networks and data center interconnects, often use partial or full mesh topologies or technologies that emulate mesh behaviour (for example, using multiple redundant links). This practical usage reflects the well-known fact that mesh topologies provide strong resilience to failure, confirming that Mesh is the correct answer.

Why Other Options Are Wrong:
Option B (Ring) is wrong because a single failure can break the ring unless special dual-ring or self-healing mechanisms are implemented.Option C (Bus) is wrong because the bus cable is a single point of failure for all attached stations.Option D (Star) is wrong because the central device is a critical single point whose failure can disable the entire network.

Common Pitfalls:
Many learners mistakenly choose star topology because they are familiar with modern Ethernet LANs that use switches in star arrangements. While such networks can be made reliable with redundant switches and links, the pure logical star still has a central dependency. Mesh topologies inherently provide multiple paths, which is why they are considered more reliable in theoretical comparisons.

Final Answer:
Mesh