In which layer of the TCP/IP layers is router or packet switch mainly used? Application layer Host-to-host, or transport layer Intemet layer Network access layer Physical layer In a sine wave function s(t)=Asin(2t+) A represents amplitutue, f represents frequency, represents phase A represents phase, f represents frequency, represents amplitutue A represents amplitutue, f represents phase, represents frequency A represents frequency, f represents amplitutue, represents phase