We can use this condition to define the payoff function of the two ISPs game. Player i (i = 1, 2) may receive chunks from
both the streaming server and from the other ISP. We define the cost of ISP i equal to Φi while if Inequality (1) holds we
assume that ISP i receives a gain of g cps.2
If (Φ1, Φ2) is the action profile, we can refine Eq. (2) and define the payoff as