ch1-1-214.pdf

Chapter 1 Review Questions (Summarized Answers) 1. Difference between host and end system? o There is no difference; both refer to devices connected to the Internet. 2. Why are standards important for protocols? o Standards ensure that different devices and system...

Chapter 1 Review Questions (Summarized Answers) 1. Difference between host and end system? o There is no difference; both refer to devices connected to the Internet. 2. Why are standards important for protocols? o Standards ensure that different devices and systems can interoperate. 3. List access technologies: o Examples include Dial-up, DSL, Cable, and Ethernet. 4. What are the layers in the Internet protocol stack? o Application, Transport, Network, Link, Physical. 5. What is the difference between circuit-switched and packet-switched networks? o Circuit-switched networks guarantee bandwidth for a session, while packet-switched networks do not. 6. Why is peering between ISPs important? o It reduces costs and latency by bypassing intermediary ISPs. 7. How does Google benefit from its private network? o It improves user experience, reduces costs, and avoids extra charges from ISPs. 8. Delay types in networking: o Processing, queuing, transmission, and propagation delays. 9. What are the five generic tasks performed by layers in a network protocol stack? o Error control, flow control, segmentation, multiplexing, connection setup. Problem-Solving Exercises (Summarized Solutions) 1. ATM Protocol Design (P1): o The ATM communicates with the bank using commands like HELO, PASSWD, BALANCE, WITHDRAW, and BYE. The server responds with messages such as OK, ERR, and AMOUNT. For successful transactions, funds are dispensed; if there are insufficient funds, the ATM displays an error. 2. End-to-End Delay for Multiple Packets (P2): o Total end-to-end delay for sending PPP packets over NNN links is (N+P−1)×LR(N + P - 1) \times \frac{L}{R}(N+P−1)×RL, where LLL is the packet size and RRR is the transmission rate. 3. Circuit vs Packet-Switched Networks (P3): o A circuit-switched network is suitable for applications with predictable bandwidth needs. Packet switching would work without congestion control if the total data rate is below the link's capacity. 4. Car-Caravan Analogy (P5): o The end-to-end delay for cars traveling between tollbooths is calculated as 57.457.457.4 minutes for 10 cars. For 8 cars, the total delay is reduced to approximately 53 minutes. 5. Propagation and Transmission Delay (P6): o Propagation delay: dprop=msd_{prop} = \frac{m}{s}dprop=sm; transmission delay: dtrans=LRd_{trans} = \frac{L}{R}dtrans=RL. The total end-to-end delay is the sum of these two. 6. Real-Time Voice Transmission Over Packet-Switched Network (P7): o The total delay is approximately 17.0417.0417.04 milliseconds, including packet creation, transmission, and propagation. 7. Sharing a 10 Mbps Link (P8): o Circuit switching supports 50 users. The probability that a user is transmitting is 0.1. Using binomial distribution, you can estimate how many users transmit simultaneously. 8. Packet-Switching vs Circuit-Switching with a 1 Gbps Link (P9): o For circuit switching, a 1 Gbps link can support 10,000 users. In packet switching, the probability of more than NNN users transmitting is calculated using a binomial formula. 9. End-to-End Delay Over Three Links (P10): o The total delay is 60.4 ms, which includes the time for transmission, propagation, and processing.