Bandwidth allocation apparatus for use in oversubscription network switching and related network switch

A network switching device, comprising:

• a plurality of first ports;
• a plurality of second ports;
• an input bandwidth allocation device, comprising:
• a buffer device, configured to receive a plurality of first data units that are transmitted from a plurality of first ports and a plurality of second data units that are transmitted from a plurality of second ports, and accordingly output the first and second data units;
• a main scheduler, coupled to the buffer device, configured to schedule the first data units and accordingly output the first data units in sequence;
• an oversubscription scheduler, coupled to the buffer device, configured to schedule the second data units and accordingly output the second data units in sequence;
• a multiplexer, coupled to the main scheduler and the oversubscription scheduler, controlled by the main scheduler to select from the first data units outputted by the main scheduler and the second data units outputted by the oversubscription scheduler to output;
• a detection device, configured to generate power-related information, wherein the main scheduler is configured to control the multiplexer according to the power-related information;
• a rate measurement device, configured to measure data transmission rates corresponding to the first and second ports to generate data transmission rate information, wherein the main scheduler is configured to control the multiplexer according to the data transmission rate information and the oversubscription scheduler is configured to schedule the second data units according to the data transmission rate information;
• and
• a routing device, coupled to the input scheduling device, configured to perform a routing process according to the first and second data units outputted by the input bandwidth allocation device;
• and
• an output bandwidth allocation device, coupled to the routing device, configured to forward the first data units and the second data units to the first ports and the second ports based on a routing result of the routing device.