Chapter 1 Homework
Problem 1 (15 pts)
Consider a single router transmitting packets, each of length L bits, over a single link with transmission rate R Mbps to another router at the other end of the link. Suppose that the packet length is L = 18000 bits, and that the link transmission rate along the link to router on the right is R = 800 Mbps. Round your answer to two decimals after leading zeros.
- Compute the one-hop transmission delay
- What is the maximum number of packets per second that can be transmitted by this link?
Problem 2 (25 pts)
Consider a network with three links, each with the specified transmission rate and link length. Link 1 transmission rate is 100 Mbps with length of 5 Km. Link 2 transmission rate is 10 Mbps and length 5000 Km, Link 3 transmission rate is 100 Mbps and length is 1 Km. The packet we are trying to send has a length of 6000 bits. The speed of light is 3*108 m/sec. Round your answers to two decimals after leading zeros.
- Calculate the transmission and propagation delays for Link 1, 2 and 3.
- What is the end to end delay for the packet?
Problem 3 (10 pts)
Consider sending a packet from a source host to a destination host over a fixed route.
- List the delay components in the end-to-end delay.
- Which of these delays are constant and which are variable?
Problem 4 (45 pts)
Consider the two scenarios below:
A circuit-switching scenario in which Ncs users, each requiring a bandwidth of 20 Mbps, must share a link of capacity 150 Mbps. A packet-switching scenario with Nps users sharing a 150 Mbps link, where each user again requires 20 Mbps when transmitting, but only needs to transmit 20 % of the time. Round your answer to two decimals after leading zeros.
- When circuit switching is used, what is the maximum number of users that can be supported?
- When packet switching is used, if there are 13 packet-switching users, can this many users be supported under circuit-switching?
- If there are 13 packet-switching users, what is the probability that a given user is transmitting, and the remaining users are not transmitting?
- What is the probability that one user (any one among the 13 users) is transmitting, and the remaining users are not transmitting? Suppose packet switching is used.
- When one user is transmitting, what fraction of the link capacity will be used by this user? Write your answer as a decimal number.
- When packet switching is used, what is the probability that any 7 users (of the total 13 users) are transmitting and the remaining users are not transmitting?
- When packet switching is used, what is the probability that more than 7 users are transmitting?
Problem 5 (5 pts)
What layer in the TCP/IP stack best corresponds to saying: ‘handles messages from a variety of network applications’?
Submit
Post your solutions in Marmoset by the scheduled due date in the syllabus.
