The network processor is communicatively coupled to {HEAD ~ the ingress module} and {TAIL ~ the egress module} 
The network processor is communicatively coupled to { HEAD ~ the ingress module } and { TAIL ~ the egress module }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL