In one embodiment, {HEAD ~ each global interface} includes {TAIL ~ a request agent} , a directory agent and a slave agent  
includes
In one embodiment , { HEAD ~ each global interface } includes { TAIL ~ a request agent } , a directory agent and a slave agent
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