A fast resume method for a first router (SGSN1) and a second router (SGSN2) for interacting with a TCP/IP based wireless radio communication system comprising a mobile station and a host (SERVER); wherein the host (SERVER) and the mobile station establishes a TCP/IP connection; and the host (SERVER) sends a data stream in the form of a sequence of segments; the mobile station sends an acknowledge frame (ACK, SEG1) to the host (SERVER) for every segment received; the method comprising the steps of: - the segments being transmitted to the mobile station by the first router (SGSN1); - receiving from the mobile station an acknowledge frame (ACK, SEG1, t1); - the first router transmitting an acknowledge frame (ACK, SEG1, t1) to the host (SERVER); characterized in that - the first router (SGSN1) copying and saving the latest acknowledge frame (ACK, SEG1); - the first router getting information whether there is contact between the MS and the first router; - if the first router gets information of a loss of contact between the MS and the first router (CON, t1+), the method comprising one of the steps - the first router (SGSN1) retransmitting the copied and saved acknowledge frame (ACK,SEG1, t2) to the host (SERVER) upon re-establishing of contact between the mobile station and the first router (SGSN1) after an interruption; - the first router repeats (SGSN1) in another two duplicate acknowledge frames (ACK, SEG1, t2) to the host or; - the first router (SGSN1) transmitting the copied and saved acknowledge frame (ACK,SEG1) to a second router (SGSN2), the second router stores the acknowledge frame (ACK,SEG1) and retransmits the saved acknowledge frame (ACK,SEG1, t2) to the host (SERVER) when contact has been established between the mobile station and the second router (SGSN2), - the second router (SGSN2) repeats transmitting the copied and saved acknowledge frame (ACK,SEG1, t2) in another two duplicate acknowledge frames to the host (SERVER). - the segments being transmitted to the mobile station by the first router (SGSN1); - receiving from the mobile station an acknowledge frame (ACK, SEG1, t1); - the first router transmitting an acknowledge frame (ACK, SEG1, t1) to the host (SERVER); - the first router (SGSN1) copying and saving the latest acknowledge frame (ACK, SEG1); - the first router getting information whether there is contact between the MS and the first router; - if the first router gets information of a loss of contact between the MS and the first router (CON, t1+), - the first router (SGSN1) retransmitting the copied and saved acknowledge frame (ACK,SEG1, t2) to the host (SERVER) upon re-establishing of contact between the mobile station and the first router (SGSN1) after an interruption; - the first router repeats (SGSN1) in another two duplicate acknowledge frames (ACK, SEG1, t2) to the host or; - the first router (SGSN1) transmitting the copied and saved acknowledge frame (ACK,SEG1) to a second router (SGSN2), the second router stores the acknowledge frame (ACK,SEG1) and retransmits the saved acknowledge frame (ACK,SEG1, t2) to the host (SERVER) when contact has been established between the mobile station and the second router (SGSN2), - the second router (SGSN2) repeats transmitting the copied and saved acknowledge frame (ACK,SEG1, t2) in another two duplicate acknowledge frames to the host (SERVER).