{HEAD ~ a data pattern enforcer} for applying said rules to packets at {TAIL ~ the adaptor layer}; and 
{ HEAD ~ a data pattern enforcer } for applying said rules to packets at { TAIL ~ the adaptor layer } ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH