Cross bar switch.

Crossbar Switch: What Does It Mean?

• A crossbar switch channels data or signals between two distinct network nodes as part of a crossbar topology. 
• The crossbar arrangement, which connects every component of an architecture to every other component, is a matrix in which every crossbar switch lies between two locations.
• Crossbar design finds application in the manufacturing of chips and electronic systems as well as networking.

• Several cross-points exist at the intersections of the paths used by the processor buses and memory modules in the Crossbar Switch system. 
• The little square at each cross-point stands in for a switch that determines the route from a CPU to a memory module. 
• Control logic is built into every switch point to configure the transfer channel between a memory and processor. It determines whether a given module is being addressed by computing the address that is inserted into the bus. 
• Furthermore, it removes several priority-based requests for access to the same memory module.

• Figure illustrates the functional design of a crossbar switch that is coupled to a single memory module. 
• Multiplexers in the circuit choose the data, address, and control from a single CPU to communicate with the memory module. 
• Priority levels were established by arbitration logic to choose one CPU among multiple CPUs attempting to access the same memory. 
• The binary code generated by a priority encoder in the arbitration logic can be utilized by the multiplexers.

• Each memory module in a crossbar switch system has its own path, which allows for simultaneous transfers from all of the modules. 
• As a result, the hardware required to implement the switch can grow to be rather complicated and huge.