An EoR (End-of-Row) switch is a network switch placed at the end of a data-center rack row, aggregating connections from multiple server racks into a centralized switching point. All servers in the row connect to the EoR switch using structured horizontal cabling, typically copper (Cat6A) or fiber. Top of rack (ToR) which is also known as In-Rack design. This means that 1 or 2 Ethernet switches are directly installed inside the rack. Designing an efficient data center network involves choosing the right architecture to balance scalability, manageability, and cost. When a server needs to be upgraded (for example, from 10GE to 25GE), only small-scale changes in cable connections. Top-of-Rack (ToR) and End-of-Row (EoR) cabling are compared because both organize server-to-network connectivity within the same data hall, yet they distribute cabling, switching, and responsibility boundaries differently. In planning discussions, they are often treated as interchangeable layouts.