T uplink=((N V *T Vcoll *P)+(N V *T Vsucc*(1???P)))+((N V *T Dcoll *P)+(N V *T Dsucc*(1???P))),where NV is the number of the voice over Internet protocol terminals connected to the system, ND is the number of the data terminals connected to the apparatus, TVcoll is a time consumed until the voice over Internet protocol terminal fails to transmit the voice packet, TVsucc represents a time which it