1. File transfer over traditional circuit-switched telephone lines (using dial-up data modems) has been the primary method of exchanging files between home users and servers. Nowadays, this has been replaced by the availability of broadband residential access networks such as DSL (digital subscriber line) and HFC (hybrid fiber coax) access networks. Consider a file transfer over a traditional circuit-switched telephone line where the file is segmented into n segments, each segment is L bits long, and the transmission passes through k, k > 1, 4ESS switches. Each link transmits at a data rate of R bps (bits/sec). To establish a circuit over the links, a delay of des seconds is incurred. (a) Give an expression for the file transfer time, denoted Tcs. Assume that the entire file transfer occurs in one call (i.e., no telephone hangup or redialling). (b) Obtain the numerical value of Tcs when n = 10 segments, L = 2 Mbits, k = 5 switches, R = 56 Kbps, and des = 500 milliseconds. 1. File transfer over traditional circuit-switched telephone lines (using dial-up data modems) has been the primary method of exchanging files between home users and servers. Nowadays, this has been replaced by the availability of broadband residential access networks such as DSL (digital subscriber line) and HFC (hybrid fiber coax) access networks. Consider a file transfer over a traditional circuit-switched telephone line where the file is segmented into n segments, each segment is L bits long, and the transmission passes through k, k > 1, 4ESS switches. Each link transmits at a data rate of R bps (bits/sec). To establish a circuit over the links, a delay of des seconds is incurred. (a) Give an expression for the file transfer time, denoted Tcs. Assume that the entire file transfer occurs in one call (i.e., no telephone hangup or redialling). (b) Obtain the numerical value of Tcs when n = 10 segments, L = 2 Mbits, k = 5 switches, R = 56 Kbps, and des = 500 milliseconds