There is provided an apparatus comprising: at least one processor; and a memory comprising code that, when executed on the at least one processor, causes the apparatus to: transmit, or arrange to transmit, a stream of packets to another apparatus; determine, at a first time, whether or not the number of packet pairs in the stream is above a threshold; and, if the number of packet pairs in the stream is determined to be below the threshold, configure future packet transmissions to the other apparatus to have more packet pairs.