An interconnect as a switch module (“ICAS” module) comprising n port groups, each port group comprising n-1 interfaces, and an interconnecting network implementing a full mesh topology where each port group comprising a plurality of interfaces each connects an interface of one of the other port groups, respectively. The ICAS module may be optically or electrically implemented. According to the embodiments, the ICAS module may be used to construct a stackable switching device and a multi-unit switching device, to replace a data center fabric switch, and to build a new, high-efficient, and cost-effective data center.