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