Problem 5 Imagine that client A needs to send 4 messages reliably to a server B over an unreliable network layer. Assume that A and B use the alternating bit protocol (rdt 3.0). Describe graphi- cally (i.e. draw a labeled diagram of) the sequence of message exchanges resulting when the 2nd message send is lost, and the ack for the 3rd message send is corrupted.

Problem 5 Imagine that client A needs to send 4 messages reliably to a server B over an unreliable network layer. Assume that A and B use the alternating bit protocol (rdt 3.0). Describe graphi- cally (i.e. draw a labeled diagram of) the sequence of message exchanges resulting when the 2nd message send is lost, and the ack for the 3rd message send is corrupted.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

See similar textbooks

Similar questions

Consider two hosts Pand Q connected through a router R. The maximum transfer unit (MTU) value of the link between Pand Ris 1500 bytes, and between Rand Qis 820 bytes. A TCP segment of size 1400 bytes was transferred from P to Q through R, with IP identification value as Ox1234. Assume that the IP header size is 20 bytes. Further, the packet is allowed to be fragmented, i.e., Don't Fragment (DF) flag in the IP header is not set by P. Which of the following statements is/are correct? (a) Two fragments are created at R and the IP datagram size carrying the second fragment is 620 bytes. (b) If the second fragment is lost, P is required to resend the whole TCP segment. (c) TCP destination port can be determined by analysing only the second fragment. (d) If the second fragment is lost, R will resend the fragment with the IP identification value Ox1234
I need answer quickly
Consider a simple congestion-control algorithm that uses linear increase and multiplicative decrease but not slow start, that works in units of packets rather than bytes, and that starts each connection with a congestion window equal to one packet. Give a detailed sketch of this algorithm. Assume the delay is latency only and that when a group of packets is sent only a single ACK is returned. Plot the congestion window as a function of round-trip times for the situation in which the following packets are lost: 9, 25, 30, 38, and 50. For simplicity, assume a perfect timeout mechanism that detects a lost packet exactly 1 RTT after it is transmitted.
1 Suppose we need to design a stop-and-wait, reliable data transfer protocol between a sender A and a receiver B, over a direct link with the following characteristics. • The channel from A to B is unreliable and can lose packets. • The channel from B to A is reliable. • Neither channel will corrupt a packet (if a packet is received, it must be correct). • Neither channel will reorder packets. The maximum RTT between A and B is known and is guaranteed to be D. For each of the following techniques for building reliable data transfer protocol, please match on whether or not, it is needed in the design of the protocol. . Acknowledgement Negative Acknowledgement Sequence Number Timeout Choose... + Choose... + Choose... + Choose... +
1. Consider a path from host A to host B through a router X as follows: A- -X-B The capacity of the link AX is denoted Ra, while the capacity of the link XB is denoted Rb in units of [bits/s]. Assume that Ra Ri. Is it possible that the second packet queues at input queue of the second link? Explain. Now suppose that host A sends the second packet T seconds after sending the first packet. How large must T be to ensure no queueing before the second link? Explain.
Suppose station X sends a message with 15 packets to station B using sliding window of size 4, selective repeat in used and every 5th packet is lost, number of transmission required to send all 15 packets to Y.
This elementary problem begins to explore propagation delay and transmission delay, two central concepts in data networking. Consider two hosts, A and B, connected by a single link of rate R bps. Suppose that the two hosts are separated by m meters, and suppose the propagation speed along the link is s meters/sec. Host A is to send a packet of size L bits to Host B. a. Express the propagation delay, dprop, in terms of m and s.b. Determine the transmission time of the packet, dtrans, in terms of L and R.c. Ignoring processing and queuing delays, obtain an expression for the end-to-end delay.d. Suppose Host A begins to transmit the packet at time t = 0. At time t = dtrans, where is the last bit of the packet?e. Suppose dprop is greater than dtrans. At time t = dtrans, where is the first bit of the packet?f. Suppose dprop is less than dtrans. At time t = dtrans, where is the first bit of the packet?g. Suppose s = 2.5 * 108 meters/sec, L = 120 bits, and R = 0.112 Mbps. Find the distance m…
Consider a simple congestion-control algorithm that uses linear increase and multiplicative decrease but not slow start, that works in units of packets rather than bytes, and that starts each connection with a congestion window equal to one packet. Give a detailed sketch of this algorithm. Assume the delay is latency only and that when a group of packets is sent only a single ACK is returned. Plot the congestion window as a function of round-trip times for the situation in which the following packets are lost: 9, 25, 30, 38, and 50. For simplicity, assume a perfect timeout mechanism that detects a lost packet exactly 1 RTT after it is transmitted.
Consider a packet of length L that begins at end system A and travels over three links to a destination end system. These three links are connected by two packet switches. Let d, s, and R denotes the length, propagation speed, and the transmission rate of link i, for i=1,2,3 . The packet switch delays each packet by d . Assuming no queuing delays, in terms of d, s , R, (i=1,2,3), and L, what is the total end-to-end delay for the packet? Suppose now the packet is 1,500 bytes, and the propagation speed on all three links are 3125km/sec, 10000 km/sec, and 3333km/sec respectively. The transmission rates of all three links are 2 Mbps, the packet switch processing delay is 3 msec, the length of the first link is 5,000 km, the length of the second 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? In the above problem, suppose R1=R2=R3=R and dproc=0. Further, suppose the packet switch does not store-and-forward packets but…
Consider a packet of length L that begins at end system A and travels over three links to a destination end system. These three links are connected by two packet switches. Let di, si, and Ri denote the length, propagation speed, and the transmission rate of link i, for i=1,2,3. The packet switch delays each packet by dproc. Assuming no queuing delays, in terms of di, si, Ri (i=1,2,3), and L, what is the total end-to-end delay for the packet? Suppose now the packet is 1,500 bytes, the propagation speed on all three links is 2.5*108 m/s, the transmission rates of all three links are 2 Mbps, the packet switch processing delay is 3 msec, the length of the first link is 5,000 km, the length of the second 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?
Suppose host A is sending a large file to host B over a TCP connection. The two end hosts are 10 msec apart (20 msec RTT) connected by a 1 Gbps link. Assume that they are using a packet size of 1000 bytes to transmit the file. For simplicity, ignore ack packets. At least how big would the window size (in packets) have to be for the channel utilization to be greater than 80%?
Consider the scenario in which a sequence of packets are sent from one site to another along a predetermined route, starting at the sending host and finishing at the receiving host. Provide a rundown of the many components that contribute to the overall end-to-end latency of a single packet. Which delays are always present, and which ones are subject to change?