Question

10. Suppose there 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? (Ignore queuing, propagation delay, and processing delay.) 11. Draw a sketch of computers and network routers and links, to show that the computers are interconnected. Indicate links that form the Network Core. (Figure 1.10)

Answer 1

Solution

Suppose there is exactly one packet switch between a sending host and a receiving host The tansmission rates between the sending host and the switch and between the switch antl the receiving host are R1 and R2, respectively Assuming that the switch uses store-and-fonvard packet switching, what is the total end-to-end delay to send a packet of length LT (Ignore queuing, propagation delay, and processing delay.)

Transmission rate between the sending host and the switch= R1

Transmission rate between the switch and receiving host = R2

Length of the packet is L

Time taken for the entire packet to reach at the router from sending host=

L/R1

Time taken for the entire packet to reach from the router to receiving host=

L/R

Thus the total delay is

LRL/R

Answer 2

Thus the total delay is L/R₁ + L/R₂