In this paper a new transmission control protocol named IISS for active RFID networks is proposed that utilizes the concept of scanning the network for successful and unsuccessful slots using lesser number of bits (compared to ISO/IEC 18000-7 standard), a new technique to adjust counters on the tags, decreased number of bits to set the protocol parameters (Frame Length and Slot Size) and reduced size of empty slots within collection rounds. This new protocol is an improved version of previously invented protocol called ISS. The results show that in comparison to the ISO 18000-7, IISS decreases the total read time by 71%, 44% and 28% when 16, 50 and 100 bytes of data are read from the tags respectively.