Method and apparatus for retransmission decision making

Abstract

A method and apparatus are described including parsing an abstraction-layer header and assigning a priority to a packet to be transmitted. A network monitor of a transmitter is connected between a network interface and a retransmission decision maker for deciding which packets to retransmit, for example, based on the assigned priority and collected network statistics or conditions, for example, packet loss rate. A network monitor may also be provided at a receiver for collecting current network statistics such as cumulative number of packets lost and for providing such statistics to a transmitter. The method further includes buffering the data to be transmitted along with the assigned priority, transmitting data retrieved from a buffer via a datagram protocol, receiving a request for retransmission of data, determining if the requested data is in the buffer and retransmitting the requested data via a protocol that provides end-to-end acknowledgement of data and error recovery.

1 . A method comprising:
 monitoring a digital data network to collect network transport statistics; and   deciding whether to retransmit a digital data packet to a receiver based on said network transport statistics.   
     
     
         2 . The method according to  claim 1  wherein
 collecting network statistics comprises collecting statistics from a receiver to generate a lost packet rate at the transmitter. 
 
     
     
         3 . The method according to  claim 2  wherein
 said packet retransmit decision is based on comparing said generated lost packet rate with a predetermined threshold. 
 
     
     
         4 . The method according to  claim 1  wherein
 collecting network statistics comprises monitoring network level transmission statistics and estimating available bandwidth. 
 
     
     
         5 . The method according to  claim 3  wherein
 said packet retransmit decision is based on comparing said estimated available bandwidth with a predetermined threshold. 
 
     
     
         6 . The method according to  claim 1  wherein
 said monitoring comprises 
 monitoring receiver missing packet data and recording data of one of packet loss rate and available bandwidth from a receiver and 
 assigning a missing packet threshold responsive to said monitoring. 
 
     
     
         7 . The method according to  claim 1  wherein
 said monitoring comprises calculating a sequence gap via a continuity counter field of a transport stream header. 
 
     
     
         8 . The method according to  claim 1  wherein
 said monitoring comprises calculating packet loss rate information from a fraction lost field of a receiver report packet. 
 
     
     
         9 . The method according to  claim 1  wherein
 said monitoring comprises calculating a packet loss rate from a base sequence number of a starting packet and an offset for an ending packet. 
 
     
     
         10 . An apparatus comprising:
 a digital data network monitor for collecting network transport statistics; and   a retransmission decision maker for deciding whether to retransmit a digital data packet based on an assigned digital data packet priority and said collected network transport statistics.   
     
     
         11 . The apparatus according to  claim 10  further comprising
 an abstraction-layer header parser coupled to a real-time transport protocol packetizer for assigning a priority level to a packet for retransmission. 
 
     
     
         12 . The apparatus according to  claim 10 ,
 said digital data monitor and said retransmission decision maker being responsive to a network interface and for providing input to a reliable media protocol module.   
     
     
         13 . The apparatus according to  claim 10  further comprising
 a buffer memory for temporary storage of digital data for transmission. 
 
     
     
         14 . The apparatus according to  claim 10  wherein
 said network monitor monitors receiver missing packet data and records data of one of packet loss rate and available bandwidth from a receiver and assigns a missing packet threshold responsive to said monitoring. 
 
     
     
         15 . The apparatus according to  claim 10  wherein
 said packet retransmit decision is based on comparing said estimated available bandwidth with a predetermined threshold. 
 
     
     
         16 . The apparatus according to  claim 10  wherein
 said network monitor calculates a sequence gap via a continuity counter field of a transport stream header. 
 
     
     
         17 . The apparatus according to  claim 14  wherein
 said network monitor calculates packet loss rate information from a fraction lost field of a receiver report packet. 
 
     
     
         18 . The apparatus according to  claim 14  wherein
 said network monitor calculates a packet loss rate from a base sequence number of a starting packet and an offset for an ending packet. 
 
     
     
         19 . The apparatus according to  claim 11  further comprising
 a buffer memory for temporary storage of digital data for retransmission according to said assigned priority level. 
 
     
     
         20 . Apparatus comprising:
 means for collecting network transport statistics; and   means for deciding whether to retransmit a digital data packet based on an assigned digital data packet priority and said collected network transport statistics.   
     
     
         21 . The apparatus according to  claim 20  further comprising
 means for packetizing data into packets; and 
 means coupled to said data packetizing means for assigning a priority level to a packet for retransmission. 
 
     
     
         22 . An apparatus comprising:
 a network monitor for collecting network statistics from the perspective of a receiver apparatus; and   a network interface for outputting a control channel message including said collected network statistics.   
     
     
         23 . An apparatus comprising:
 means for collecting network statistics from the perspective of a receiver apparatus; and   means for outputting a control channel message including said collected network statistics.