Switching - backplane
Network devices such as switches and routers have what is known as a backplane. This is essentially the physical circuit board that interconnects the ports on the switch or a router. If you were to open up such a device, the backplane is essentially the circuit board to which all of the ports are connected. It’s also where other physical components like the power supply, memory, and any processors are connected to. It’s kind of like the motherboard of the device, but refers mostly to the physical path or backbone through which data packets travel from one port to another. The capacity of the backplane (measured in bps - bits per second) determines the maximum data throughput of the switch or router.
Compare the backplane to the switch fabric which contains much of the logical components and mechanisms involved in moving packets from one port to another.