Router providing differentiated quality of service (QoS) and fast internet protocol packet classifying method for the router

A packet classification method comprising:

• extracting a multi-field search key from an incoming packet;
• extracting a differential service code point field from the extracted multi-field search key;
• classifying the incoming packet according to differential classes in response to the extracted differential service code point field;
• searching a first flow table group corresponding to the differential service code point field in response to the multi-field search key;
• extracting operation codes from the search result if the first flow table group search succeeded;
• and
• searching a second flow table group corresponding to the differential service code point field in response to the multi-field search key if the first flow table group search failed, and extracting operation codes from, the second flow table group search result,
• wherein the first flow table group is stored in a first memory and the second flow table group is stored in a second memory.