What drives the decision to implement a two-tier versus a three-tier network architecture?

The decision to implement a two-tier versus a three-tier network architecture is primarily influenced by the number of network blocks within an organization. In a two-tier architecture, you typically have a more simplified structure, which includes only an access layer and a distribution layer. This model works well in environments where the number of network blocks is limited, and you can manage them efficiently without the overhead of additional layers.

When the number of network blocks increases, a three-tier architecture becomes preferable. This model introduces a core layer that serves as a centralized point for the distribution layer to connect to, allowing for greater scalability and performance management. It also helps facilitate redundancy and load balancing, essential in larger, more complex networks where the number of users, devices, and network traffic can significantly increase.

While factors like the number of users, application types, and physical layout can influence network design decisions, the primary driving force distinguishing between a two-tier and a three-tier architecture is the number of network blocks that need to be managed. In instances with a higher number of blocks, the complexity and functional requirements necessitate the robustness of a three-tier architecture to ensure optimal performance and management.