Suppose these is exactly one packet switch between a sending host and a receiving host. The transmission rates between the sending host and the switch and between the switch and the receiving host are R1 and R2 respectively. Assuming that the switch uses store-and-forward packet switching, what is the total end-to-end delay to send a packet of length L

l/R1 + l/R2

Explanation:

Assuming the length of the packet = l

The transmission rate between sending host and switch = R1

The transmission rate between the switch and the receiving host = R2

The store and forward packet-switching stores packets and validates them before transmitting them to the receiving host. So the end-to-end delay L is the sum of the transmission delay from the sending host to the switch and the switch to the receiving host, that is;

L = l/R1 + l/R2