{TAIL ~ The hash values} for {HEAD ~ the connections} detected during the predetermined time period preceding the current time period are stored in the second table 
{ TAIL ~ The hash values } for { HEAD ~ the connections } detected during the predetermined time period preceding the current time period are stored in the second table
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH