The repair server maintains an ordered list of the retransmit servers that are most likely to have buffered copies of {HEAD ~ packets} missing from {TAIL ~ the session} 
missing from
The repair server maintains an ordered list of the retransmit servers that are most likely to have buffered copies of { HEAD ~ packets } missing from { TAIL ~ the session }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL