The RA provides a subsystem with {TAIL ~ a mechanism} for sending {HEAD ~ read and write request} to the DA of another subsystem 
The RA provides a subsystem with { TAIL ~ a mechanism } for sending { HEAD ~ read and write request } to the DA of another subsystem
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH