Host detection method for network switch and system thereof

A system for host detection, comprising:

• an SDN switch having a memory used to record a plurality of flow entries;
• an SDN controller performing a host detection method for a network switch, wherein the SDN controller communicates with the SDN switch by an OpenFlow protocol and the method includes:
• adding a first flow entry with a meter when the SDN switch is online, and adding a second flow entry that is used to match an ARP packet;
• receiving packets from one or more hosts, and the SDN controller learning a MAC address of each host through the first flow entry or the second flow entry;
• metering within a timeout period;
• a meter of the SDN switch controlling an amount of packets entering a central processor of the SDN switch so as to reduce loading of the central processor of the SDN switch;
• adding the same number of third flow entries as the number of detected hosts, utilizing a counter to count the data flow of the hosts, and detecting if each host is online according to a counting result;
• and
• adding the same number of fourth flow entries as the number of detected hosts for updating MAC address and IP address of every host;
• wherein the host is detected to be online or offline through the first flow entry, the second flow entry, the third flow entry, the fourth flow entry and a fifth flow entry, so as to reduce loading of the central processor of the SDN switch.