Switch device and flow control method

A switch device, comprising:

• a plurality of local connection ports;
• a plurality of cascade connection ports configured to be connected to a plurality of external switch devices;
• a buffer memory;
• and
• a processing unit coupled to the buffer memory, the local connection ports and the cascade connection ports, the processing unit being configured for:
• determining a source connection port of an input packet transmitted to the switch device;
• obtaining a plurality of input counts corresponding to each of the local connecting connection ports, each of the cascade connecting connection ports, the switch device and the external switch devices;
• determining whether an input congestion occurs at the source connection port according to the input counts;
• in response to the input congestion not occurring at the source connection port, storing the input packet into the buffer memory and updating the input counts;
• and
• in response to the input congestion occurring at the source connection port, sending a pause notification to the source connection port or discarding the input packet.