Answer:
[tex]L(\frac{1}{R_1}+\frac{1}{R_2} )[/tex]
Explanation:
[tex]R_1[/tex] is the transmission rates between the sending user and the switch while [tex]R_2[/tex] is the transmission rates between the switch and the receiving user and the length of the packet is L
Considering no propagation delay the time taken to transmit the packet from the sending user to the switch is given as:
[tex]t_1=\frac{L}{R_1}[/tex]
the time taken to transmit the packet from the switch to the receiving user is given as:
[tex]t_2=\frac{L}{R_2}[/tex]
therefore the total end-to-end delay to send a packet is:
[tex]t=t_1+t_2=\frac{L}{R_1}+\frac{L}{R_2} =L(\frac{1}{R_1}+\frac{1}{R_2} )[/tex]