wherein applying the set of attack patterns comprises applying a first set of patterns defined by {HEAD ~ a first policy} to {TAIL ~ the first portion} of the network traffic to detect the first set of corresponding network attacks and applying a second set of patterns defined by a second policy to the second portion of the network traffic to detect the second set of corresponding network attacks, the first set of patterns and the second set of patterns differing by at least one pattern, and 
to
wherein applying the set of attack patterns comprises applying a first set of patterns defined by { HEAD ~ a first policy } to { TAIL ~ the first portion } of the network traffic to detect the first set of corresponding network attacks and applying a second set of patterns defined by a second policy to the second portion of the network traffic to detect the second set of corresponding network attacks , the first set of patterns and the second set of patterns differing by at least one pattern , and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH