System and method for reliable virtual bi-directional data stream communications with single socket point-to-multipoint capability

Abstract

An improved system and method are disclosed for reliable virtual bi-directional data stream (RVBDDS) connections. In one example, two communication devices create and exchange streaming data packets that are encapsulated in connection-less transport layer packets. The streaming data packets contain information used in managing the RVBDDS connection between the two devices.

What is claimed is: 
     
         1 . A method for streaming data using a virtual bi-directional data stream between a first communication device and a second communication device comprising:
 creating, by the first device, a streaming data packet D 1 ;   inserting, by the first device, a data segment and D 1  into a payload section of a connection-less transport layer packet, wherein at least one of D 1  and the connection-less transport layer packet includes a send field identifying a starting location in the data stream of the data segment to be sent with D 1 , an acknowledgement (ACK) field identifying a location in the data stream up to which all data has been received by the first device, a unique identifier (UID) identifying a connection used by the first device for the data stream, a window field identifying an amount of space available in a receive buffer of the first device, a packet type field, a pad field identifying an amount of padding used to ensure D 1  has a predefined length, a network address of the first device, a network address of the second device, and a length of the connection-less transport layer packet;   sending, by the first device, the connection-less transport layer packet to the second device;   obtaining, by the first device, a current round trip time (RTT) that is based on first and second RTTs of packets previously sent from the first device to the second device and a configurable RTT variation factor, wherein the obtaining includes calculating, by the first device, the current RTT as the RTT for a streaming data packet D 2  previously sent from the first device to the second device as RTT=RTT+((CurrRTT−OldRTT)*1/M), wherein CurrRTT represents the first RTT of a streaming data packet D 3  that was sent prior to D 2  from the first device to the second device, OldRTT represents the second RTT of a streaming data packet D 4  that was sent prior to D 3  from the first device to the second device, and M represents the configurable RTT variation factor;   obtaining, by the first device, a current RTT variance that is based on a previous RTT variance, the first and second RTTs, and a configurable RTT variance variation factor, wherein the obtaining includes calculating, by the first device, the current RTT variance (RTTvar) as the RTTvar that was calculated for D 2  as RTTvar=RTTvar+((CurrRTTVar−Abs(CurrRTT−OldRTT))*1/N), wherein CurrRTTVar represents an RTTvar of D 3  and is the previous RTT variance, and N represents the configurable RTT variance variation factor;   calculating, by the first device, a timeout for D 1  based on the current RTT and the current RTT variance; and   resending, by the first device, D 1  if the timeout does not exceed a predefined timeout limit and if an ACK for D 1  has not been received from the second device.