The repair server detects that packets are missing from the session it receives and in response, it sequentially requests the missing packets from {HEAD ~ respective ones} of {TAIL ~ the plurality} of retransmit servers 
The repair server detects that packets are missing from the session it receives and in response , it sequentially requests the missing packets from { HEAD ~ respective ones } of { TAIL ~ the plurality } of retransmit servers
OTH OTH OTH OTH 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 HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH