Network delay depends on the physical link delay and the available bandwidth (including the queue delays caused by the routing). This second parameter is strongly related to the network load, and therefore, the network delay is a time-varying amount of time. Moreover, because the network diameter in the P2PSP is 2, the network delay must to be taken into account twice. Let us denote this time by . Let us denote the network delay at physical link . Due to the diameter of the P2PSP an upper bound of the network delay is .