middle of row (data center) (MoR)
Middle of Row (MoR) is a data center networking concept. In Middle of Row, the MoR switch is located in the middle between the server racks. It is different with End of Row( EoR) where the EoR switch is located at the end of the server racks and Top of Rack( ToR) where the ToR switches are located on top of the racks.
In the different switch concepts, the cabling is optimized; both in terms of cable length, which in many cases must not exceed a length of a few meters, and the transmittable data rates.
In the MoR concept, all servers from the different racks are connected to the middle-of-row switch without the individual rack switches being networked beforehand, as is the case with the ToR concept. The MoR switches are located in the middle of the row of racks, which means that the cable lengths are shorter than in the EoR concept.
The MoR switches are flexibly configurable and can be extended by a plug-in card if required. The number of ports is lower with this concept than with the ToR concept.