TOR, EOR and MOR refer to the layout of data center switches.

1.TOR (Top of Rack), literally, is not difficult to understand. The TOR switch is deployed on the top of the cabinet. The servers in the cabinet are connected to the switch through optical fibers or network lines, and the switch is connected to the upper convergent switch. In this case, it is suitable for the situation of more access equipment or high density of single cabinet equipment. Through distributed access, the connection between server cabinet and network cabinet can be reduced, and the connection management is simple. But at the same time, access switches are scattered in multiple cabinets, which is not conducive to centralized maintenance and management of switches.

2.EOR (End of Row) refers to the centralized deployment of access switches in one or two cabinets at the end of each cabinet, where all servers are connected to the switch through horizontal routes. This situation is more common, using EOR method to connect, there will be a large number of cable connections from multiple server cabinets converged into the network cabinet, connection management is difficult, but the centralized maintenance and management of switches is convenient.

3.MOR (Middle of Row), the connection mode of MOR switch is similar to EOR mode. Access switches are deployed in one or two cabinets of a cabinet group through centralized mode, only the location of network cabinet is in the middle of the cabinet group. In this case, the connection between server cabinet and network cabinet will be simplified. At the same time, the switch has been centralized management, which is a compromise between TOR and EOR.