초록 ▼

In a digital data transmission system using sliding-window flow control with an adjustable window size on a non-transparent data connection whose nominal data transmission rate may vary during the connection, a receiving party delays the transmission of a retransmission request for a missing frame f

In a digital data transmission system using sliding-window flow control with an adjustable window size on a non-transparent data connection whose nominal data transmission rate may vary during the connection, a receiving party delays the transmission of a retransmission request for a missing frame for the duration of a delay, so that the receiving party may ensure that the missing frame has not been moved to be sent later in the same group or in next groups. If the missing frame is received later in the same group or in the next groups within said delay, no retransmission request is sent. If the missing frame is not received by the end of the delay, a retransmission request is sent. This eliminates unnecessary retransmissions due to the wrong frame order, and resulting loading or congestion. This results in a higher throughput on the data connection. If grouping is not being used, retransmission is not delayed unless a delay is needed for another reason.

대표청구항 ▼

[ We claim:] [1.] A digital data transmission system, said system comprising:a transmitting party;a receiving party;a non-transparent circuit-switched data connection between said transmitting and receiving parties for transmitting and receiving data in data frames;a data flow control protocol invol

[ We claim:] [1.] A digital data transmission system, said system comprising:a transmitting party;a receiving party;a non-transparent circuit-switched data connection between said transmitting and receiving parties for transmitting and receiving data in data frames;a data flow control protocol involving transmitting said data frames by said transmitting party in a preset order on said data connection, checking the order of receiving of said data frames by said receiving party, based on order information included in said data frames, acknowledging by said receiving party properly received data frames, and retransmitting erroneous or missing data frames by said transmitting party;said transmitting party being capable of temporarily grouping data frames being transmitted; andsaid receiving party being arranged to send, upon detecting a missing data frame, based on order information included in each respective two of said data frames received in succession, a retransmission request for said missing data frame only after a delay of a predetermined duration, wherein said delay of said predetermined duration is for ensuring that said missing frame has not been transmitted in a manner which would result in said missing frame being received by said receiving party subsequent to said receiving party receiving the second of said respective two of said data frames received in succession, if said transmission request was not sent and wherein said predetermined duration of said delay is dependent on said grouping of said data frames by said transmitting party. [5.] The system as claimed in claim 1, wherein:said predetermined duration of said delay is equal to the time needed for receiving a given number of said data frames by said receiving party.