Computer Communication Networks Course 1 (85.06 KiB) Viewed 45 times
Computer Communication Networks Course 2 (85.06 KiB) Viewed 45 times
Computer Communication Networks Course 3 (85.06 KiB) Viewed 45 times
Computer Communication Networks Course 4 (22.37 KiB) Viewed 45 times
Problem II: Delays with multiple links: (40 Points) Consider a packet of length L that begins at end system A, travels over one link to a packet switch, and travels from the packet switch over a second link to a destination end system B. Let di, si and Ri denote the length, propagation speed, and transmission rate of link i, for i = 1, 2. The packet switch delays each packet by dproc (Processing Delay). 1. [6 Points] Draw the network diagram for this scenario. 2. [8 Points] Suppose the packet switch is working using the store and forward mode. Furthermore, suppose there are no queuing delays. In terms of di, si and R; (i = 1,2) and L, what is the total end-to-end delay for the packet? [Justify your answer and show all steps and all your work] 3. [8 Points] Suppose the packet is 1,000 bytes, the propagation speed on each link is 2.5 x 108 m/s, the transmission rates of each link is 1 Mbps, the packet switch processing delay is 1 msec, the length of the first link is 4,000 km, and the length of the last link is 1,000 km. For these values, what is the end-to-end delay for the packet? (Hint: The packet switch is also working using the store and forward mode.) [Justify your answer and show all steps and all your work] 4. Suppose Host A begins to transmit the packet at t time to = 0. a. [6 Points] At time dtrans, where is the last bit and the first bit of the package? Justify your answer. b. [6 Points] If dprop > dtrans, at time dtrans where is the first bit and the last bit of the packet? Justify your answer. c. [6 Points] Say that dprop <dtrans. Where would the first bit and the last bit at time dtrans? Justify your answer.
4. Suppose Host A begins to transmit the packet at t time to = 0. a. [6 Points] At time dtrans, where is the last bit and the first bit of the package? Justify your answer. b. [6 Points] If dprop > dtrans, at time dtrans where is the first bit and the last bit of the packet? Justify your answer. c. [6 Points] Say that dprop <dtrans. Where would the first bit and the last bit at time dtrans? Justify your answer.
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