1 Chapter 1 1) p. 98: P-6 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 single link of rate R bps. Suppose that the two hosts are separated by m meter, 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 = d trans, 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 = , L = 120 bits, and R = 56 kbps. Find the distance m so that dprop equals dtrans. a) d prop = m / s seconds. b) d trans = L / R seconds. c) d end to end = ( m / s + L / R) seconds. d) The bit is just leaving Host A. e) The first bit is in the link and has not reached Host B. f) The first bit has reached Host B. g) Want m L = s R ( ) 536 = = km.
2 2) p. 102: P-25 Suppose two hosts, A and B, are separated by 20,000 kilometers and are connected by a direct link of R= 2Mbps. Suppose the paopagation speed over the link is meters/sec. a. Calculate the bandwidth-delay product, R dprop. b. Consider sending a file of 800,000 bits from Host A to Host B. Suppose the file is sent continuously as one large message. What is the maximum number of bits that will be in the link at any given time? c. Provide and interpretation of the bandwidth-delay product. d. What is the width ( in meters ) of a bit in the link? Is it longer than a foot-ball field? e. Derive a general expression for the width of a bit in terms of the propagation speed s, the transmission rate R, and the length of the link m. a) 160,000 bits b) 160,000 bits c) The bandwidth-delay product of a link is the maximum number of bits that can be in the link. d) the width of a bit = length of link / bandwidth-delay product, so 1 bit is 125 meters long, which is longer than a football field e) m/((m/s)*r) = s/r
3 Chapter 2 1) p. 200: P-10 Consider a short, 15-meters link, over which a sender can transmit at a rate of 160 bits/sec in both directions. Suppose that packets containing data are 200,000 bits long, and packets containing only control (e.g., ACK or handshaking) are 100 bits long. Assume that N parallel connections each get 1/N of the link bandwidth. Now consider the HTTP protocol, and suppose that each downloaded object is 200 Kbits long, and that the initial downloaded object contains 10 referenced objects from the same sender. Would parallel downloads via parallel instances of non-persistent HTTP makes sense in this case? Now consider persistent HTTP. Do you expect significant gains over the non-persistent case? Justify and explain your answer. Note that each downloaded object can be completely put into one data packet. Let Tp denote the one-way propagation delay between the client and the server. First consider parallel downloads via non-persistent connections. Parallel download would allow 10 connections share the 160 bits/sec bandwidth, thus each gets just 16 bits/sec. Thus, the total time needed to receive all objects is given by: (100/160+Tp + 100/160 +Tp + 100/160+Tp + 200,000/160+ Tp ) + (100/(160/10)+Tp + 100/(160/10) +Tp + 100/(160/10)+Tp + 200,000/(160/10)+ Tp ) = *Tp (seconds) Then consider persistent HTTP connection. The total time needed is give by: (100/60+Tp + 100/160 +Tp + 100/160+Tp + 200,000/160+ Tp ) + 10*(100/160+Tp + 200,000/160+ Tp ) = *Tp (seconds) Assume the speed of light is 300*10 6 m/sec, then Tp=15/(300*10 6 )=0.05 microsec. Tp is negligible compared with transmission delay. Thus, we see that the persistent HTTP does not have significant gain over the non-persistent case with parallel download.
4 2) p. 200: P-11 Consider the scenario introduced in the previous problem. Now suppose that the link is shared by Bob with four other users. Bob uses parallel instances of non-persistent HTTP, and the other four users use non-persistent HTTP without parallel downloads. a. Do Bob s parallel connections help him get Web pages more quickly? Why or why not? b. If all five users open five parallel instances of non-persistent HTTP, then would Bob s parallel connections still be beneficial? Why or why not? a) Yes, because Bob has more connections, he can get a larger share of the link bandwidth. b) Yes, Bob still needs to perform parallel downloads; otherwise he will get less bandwidth than the other four users.
5 Chapter 3 1) P.321: P-37 Compare GBN, SR, and TCP (no delayed ACK). Assume that the timeout values for all three protocols are sufficiently long such that 5 consecutive data segments and their corresponding ACKs can be received (if not lost in the channel) by the receiving host (Host B) and the sending host (Host A) respectively. Suppose Host A sends 5 data segments to Host B, and the 2nd segment (sent from A) is lost. In the end, all 5 data segments have been correctly received by Host B. a. How many segments has Host A sent in total and how many ACKs has Host B sent in total? What are their sequence numbers? Answer this question for all three protocols. b. If the timeout values for all three protocol are much longer than 5 RTT, then which protocol successfully delivers all five data segments in shortest time interval? a) Go Back N: A sends 9 segments in total. They are initially sent segments 1, 2, 3, 4, 5 and later re-sent segments 2, 3, 4, and 5. B sends 8 ACKs. They are 4 ACKS with sequence number 1, and 4 ACKS with sequence numbers 2, 3, 4, and 5. Selective Repeat: A sends 6 segments in total. They are initially sent segments 1, 2, 3, 4, 5 and later re-sent segments 2. B sends 5 ACKs. They are 4 ACKS with sequence number 1, 3, 4, 5. And there is one ACK with sequence number 2. TCP: A sends 6 segments in total. They are initially sent segments 1, 2, 3, 4, 5 and later re-sent segments 2. B sends 5 ACKs. They are 4 ACKS with sequence number 2. There is one ACK with sequence numbers 6. Note that TCP always send an ACK with expected sequence number. b) TCP. This is because TCP uses fast retransmit without waiting until time out.
6 2) P. 324: P-46 Consider that only a single TCP (Reno) connection uses one 15Mbps link which does not buffer any data. Suppose that this link is the only congested link between the sending and receiving hosts. Assume that the TCP sender has a huge file to send to the receiver, and the receiver s receive buffer is much larger than the congestion window. We also make the following assumptions: each TCP segment size is 1,200 bytes; the two-way propagation delay of this connection is 160 msec; and this TCP connection is always in congestion avoidance phase, that is, ignore slow start. a. What is the maximum window size (in segment) that this TCP connection can achieve? b. What is the average window size (in segment) and average throughput (in bps) of this TCP connection? c. How long would it take for this TCP connection to reach its maximum window again after recovering from a packet loss? a) Let W denote the max window size measured in segments. Then, W*MSS/RTT = 15Mbps, as packets will be dropped if the maximum sending rate exceeds link capacity. Thus, we have W*1200*8/0.16=15*10^6, then W is about 250. b) As congestion window size varies from W/2 to W, then the average window size is 0.75W=187.5 segments. Average throughput is 187.5*1200*8/0.16=11.25Mbps. c) (250/2) *0.16= 20 seconds, as the number of RTTs (that this TCP connections needs in order to increase its window size from W/2 to W) is given by W/2. Recall the window size increases by one in each RTT.
7 Chapter 4 1) P. 448: P-26 Consider the following network. With the indicated link costs, use Dijkstra s shortest-path algorithm to compute the shortest path from x to all network nodes. Show how the algorithm works by computing a table similar to Table 4.3. Step N D(t),p(t) D(u),p(u) D(v),p(v) D(w),p(w) D(y),p(y) D(z),p(z) 0 x 3,x 6,x 6,x 8,x 1 xv 7,v 6,v 3,x 6,x 6,x 8,x 2 xvu 7,v 6,v 3,x 6,x 6,x 8,x 3 xvuw 7,v 6,v 3,x 6,x 6,x 8,x 4 xvuwy 7,v 6,v 3,x 6,x 6,x 8,x 5 xvuwyt 7,v 6,v 3,x 6,x 6,x 8,x 6 xvuwytz 7,v 6,v 3,x 6,x 6,x 8,x 2) P. 449-P.27 Consider the network shown in Problem 26. Using Dijkstra s algorithm, and showing your work using a table similar to Table 4.3, do the following: a. Compute the shortest path from t to all network nodes. b. Compute the shortest path from u to all network nodes. c. Compute the shortest path from v to all network nodes. d. Compute the shortest path from w to all network nodes. e. Compute the shortest path from y to all network nodes. f. Compute the shortest path from z to all network nodes.
9 Step N D(x), p(x) D(u),p(u) D(v),p(v) D(t),p(t) D(y),p(y) D(z),p(z) w 6,w 3,w 4,w wu 6,w 3,w 4,w 5,u wuv 6,w 3,w 4,w 5,u 12,v wuvt 6,w 3,w 4,w 5,u 12,v wuvtx 6,w 3,w 4,w 5,u 12,v 14,x wuvtxy 6,w 3,w 4,w 5,u 12,v 14,x wuvtxyz 6,w 3,w 4,w 5,u 12,v 14,x e) Step N D(x), p(x) D(u),p(u) D(v),p(v) D(w),p(w) D(t),p(t) D(z),p(z) y 6,y 8,y 7,y 12,y yx 6,y 8,y 12,x 7,y 12,y yxt 6,y 9,t 8,y 12,x 7,y 12,y yxtv 6,y 9,t 8,y 12,x 7,y 12,y yxtvu 6,y 9,t 8,y 12,x 7,y 12,y yxtvuw 6,y 9,t 8,y 12,x 7,y 12,y yxtvuwz 6,y 9,t 8,y 12,x 7,y 12,y f) Step N D(x), p(x) D(u),p(u) D(v),p(v) D(w),p(w) D(y),p(y) D(t),p(t) z 8,z 12,z zx 8,z 11,x 14,x 12,z zxv 8,z 14,v 11,x 14,x 12,z 15,v zxvy 8,z 14,v 11,x 14,x 12,z 15,v zxvyu 8,z 14,v 11,x 14,x 12,z 15,v zxvyuw 8,z 14,v 11,x 14,x 12,z 15,v zxvyuwt 8,z 14,v 11,x 14,x 12,z 15,v 3) P. 450: P-34 Consider Figure Suppose there is another router w, connected to router y and z. The costs of all links are given as follows: c(x, y) = 4, c (x, z) = 50, c (y, w) = 1, c (z, w) = 1, c (y, z) = 3. Suppose that poisoned reverse is used in the distance-vector routing algorithm.
10 a. When the distance vector routing is stabilized, router w, y, and z inform their distances to x to each other. What distance values do they tell each other? b. Now suppose that the link cost between x and y increases to 60. Will there be a count-to-infinity problem even if poisoned reverse is used? Why or why not? If there is a count-to infinity problem, then how many iterations are needed for the distance-vector routing to reach a stable state again? Justify your answer. c. How do you modify c (y, z) such that there is no count-to-infinity problem at all if c (y, x) changes from 4 to 60? a) Router z Router w Router y Informs w, Dz(x)= Informs y, Dz(x)=6 Informs y, Dw(x)= Informs z, Dw(x)=5 Informs w, Dy(x)=4 Informs z, Dy(x)=4 b) Yes, there will be a count-to-infinity problem. The following table shows the routing converging process. Assume that at time t0, link cost change happens. At time t1, y updates its distance vector and informs neighbors w and z. In the following table, stands for informs. Time t0 t1 t2 t3 t4 Z w, Dz(x)= No change w, Dz(x)= y, Dz(x)=6 y, Dz(x)=11 W y, Dw(x)= y, Dw(x)= No change z, Dw(x)=5 z, Dw(x)=10 Y w, Dy(x)=4 w, Dy(x)=9 No change w, Dy(x)=14 z, Dy(x)=4 z, Dy(x)= z, Dy(x)= We see that w, y, z form a loop in their computation of the costs to router x. If we continue the iterations shown in the above table, then we will see that, at t27, z detects that its least cost to x is 50, via its direct link with x. At t29, w learns its least cost to x is 51 via z. At t30, y updates its least cost to x to be 52 (via w). Finally, at time t31, no updating, and the routing is stabilized.
11 Time t27 t28 t29 t30 t31 Z w, Dz(x)=50 via w, y, Dz(x)=50 via y, 55 via z, 50 W y, Dw(x)= y, Dw(x)=51 via w, z, Dw(x)=50 z, Dw(x)= via y, via z, 51 Y w, Dy(x)=53 w, Dy(x)= via w, 52 z, Dy(x)= z, Dy(x)= 52 via y, 60 via z, 53 c) cut the link between y and z. Chapter 5 1) p. 530: P-8 In section 5.3, we provide an outline of the derivation of the efficiency of slotted ALOHA. In this problem we ll complete the derivation. a. Recall that when there are N active nodes, the efficiency of slotted ALOHA is NP(1-P) N-1. Find the value of p that maximizes this expression. b. Using the value of p found in (a), find the efficiency of slotted ALOHA by letting N approach infinity. Hint: (1-1/N) N approaches 1/e as N approaches infinity. a) b) E( p) = Np(1 p) E' ( p) = N(1 p) = N (1 p) N 2 E' ( p) = 0 p* = N 1 N 1 Np( N 1)(1 p) ((1 p) p( N 1)) 1 N 1 1 E( p*) = N (1 ) N N N 1 1 = (1 ) N N 1 N 2 1 (1 ) = N 1 1 N 1 1 N 1 lim (1 ) = 1 lim (1 ) = N N N N e N Thus
12 1 lim E( p*) = N e 2) P. 532: P-18 Suppose nodes A and B are on the same 12 Mbps broadcast channel, and the propagation delay between the two nodes is 316 bit times. Suppose CSMA/CD and Ethernet packets are used for this broadcast channel. Suppose node A beings transmitting a frame and, before it finishes, node B begins transmitting a frame. Can A finish transmitting before it detects that B has transmitted? Why or why not? If the answer is yes, then A incorrectly believes that its frame was successful transmitted without a collision. Hint: Suppose at time t = 0 bits, A begins transmitting a frame. In the worst case, A transmits a minimum-sized frame of bit times. So A would finish transmitting the frame at t = bit times. Thus, the answer is no, if B s signal reaches A before bit time t = bits. In the worst case, when does B s signal reach A? At t = 0, A transmits. At t = 576, A would finish transmitting. In the worst case, B begins transmitting at time t=315, which is the time right before the first bit of A s frame arrives at B. At time t= =631, B 's first bit arrives at A. Because 631 > 576, A finishes transmitting before it detects that B has transmitted. So A incorrectly thinks that its frame was successfully transmitted without a collision.
13 Chapter 7 1) P. 685: P-2 Recall the simple model for HTTP streaming shown in Figure 7.3. Recall that B denotes the size of the client s application buffer, and Q denotes the number of bits that must be buffered before the client application begins playout. Also r denotes the video consumption rate. Assume that the server sends bits at a constant rate x whenever the client buffer is not full. a. Suppose that x < r. As discussed in the text, in this case playout will alternate between periods of continuous playout and period of freezing. Determine the length of each continuous playout and freezing period as a function of Q, r, and x. b. Now suppose that x > r. At what time t = tf does the client application buffer become full? a) During a playout period, the buffer starts with Q bits and decreases at rate r - x. Thus, after Q/(r - x) seconds after starting playback the buffer becomes empty. Thus, the continuous playout period is Q/(r - x) seconds. Once the buffer becomes empty, it fills at rate x for Q/x seconds, at which time it has Q bits and playback begins. Therefore, the freezing period is Q/x seconds. b) Time until buffer has Q bits is Q/x seconds. Time to add additional B - Q bits is (B - Q)/(x - r) seconds. Thus the time until the application buffer becomes full is seconds. 2) P. 685: P-3 Recall the simple model for HTTP streaming shown in Figure 7.3. suppose the buffer size is infinite but the server sends bits at variable rate x(t). Specifically, suppose x (t) has the following saw-tooth shape. The rate is initially zero at time t = 0 and linearly climbs to H at time t = T. It then repeats this pattern again and again, as shown in the figure below. a. What is the server s average send rate? b. Suppose that Q = 0, so that the client starts playback as soon as it receives a video frame. What will happen? c. Now suppose Q > 0. Determine as a function of Q, H, and T the time at which playback first begins. d. Suppose H > 2r and Q = HT/2. Prove there will be no freezing after the initial playout delay.
14 e. Suppose H > 2r. Find the smallest value of Q such that there will be no freezing after the initial playback delay. f. Now suppose that the buffer size B is finite. Suppose H > 2r. As a function of Q, B, T, and H, determine the time t = tf when the client application buffer first becomes full. a) The server s average send rate is. b) This part (b) is an odd question and will be removed from the next edition. After playing out the first frame, because x(t) < r, the next frame will arrive after the scheduled playout time of the next frame. Thus playback will freeze after displaying the first frame. c) Let q(t) denote the number of bits in the buffer at time t. Playout begins when q(t) = Q. Let s assume throughout this problem that HT/2 Q, so that q(t) = Q by the end of the first cycle for x(t). We have. Therefore, q (t) = Q when t = = tp. d) At time t = T, q (t) = HT/2 = Q, so that playout begins. If subsequently there is no freezing, we need q(t + T) > 0 for all t T, we have > With t = nt +, with 0 < < T, we have from above
15 Which is easily seen to be possible for all 0 < < T. = e) First consider the [0, T]. We have for tp t T q (t) is minimized at t = rt/h. It can then be shown that q (rt/h) 0 if and only if tp rt/2h. Furthermore, if tp = rt/2h, proof can be extended to show q (t) > 0 for all t T thus, tp < rt/2h and Q = r2t/8h. f) This is a very challenging problem. Assuming that B is reached before time T, then tf is solution to = B.
1 First Midterm for ECE374 03/24/11 Solution!! Note: In all written assignments, please show as much of your work as you can. Even if you get a wrong answer, you can get partial credit if you show your
1 Homework 2 assignment for ECE374 Posted: 02/21/14 Due: 02/28/14 Note: In all written assignments, please show as much of your work as you can. Even if you get a wrong answer, you can get partial credit
Computer Networks Homework 1 Reference Solution 1. (15%) Suppose users share a 1 Mbps link. Also suppose each user requires 100 kbps when transmitting, but each user transmits only 10 percent of the time.
5-44: omputer Networks Homework 2 Solution Assigned: September 25, 2002. Due: October 7, 2002 in class. In this homework you will test your understanding of the TP concepts taught in class including flow
EXAMPLES AND PROBLEMS Competence Based Education Internet Protocols Example 1 In following figure frames are generated at node A and sent to node C through node B. Determine the minimum transmission rate
Islamic University of Gaza Faculty of Engineering Computer Engineering Department Networks Discussion ECOM 4021 Lecture # 2 CH1 Computer Networks and the Internet By Feb 2013 (Theoretical material: page
COMP 361 Computer Communications Networks Fall Semester 2003 Midterm Examination Date: October 23, 2003, Time 18:30pm --19:50pm Name: Student ID: Email: Instructions: 1. This is a closed book exam 2. This
COMP 333/933 Computer Networks and Applications Tutorial (Week 6) Introduction Problem Set, Question 7 Suppose two hosts, A and B are separated by, kms and are connected by a direct link of R = Mbps. Suppose
CSE3214 Computer Network Protocols and Applications Chapter 1 Examples and Homework Problems Example 1 (review question 18) (1) How long does it take a packet of length 1000 bytes to propagate over a link
Data Networks Summer Homework # Assigned June 8, Due June in class Name: Email: Student ID: Problem Total Points Problem ( points) Host A is transferring a file of size L to host B using a TCP connection.
CS 5480/6480: Computer Networks Spring 2012 Homework 3 Due by 1:25 PM MT, Monday March 5 th 2012 Important: No cheating will be tolerated. No Late Submission will be allowed. Total points for 5480 = 37
EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Mathematics and Computer Science Examination Computer Networks (2IC15) on Monday, June 22 nd 2009, 9.00h-12.00h. First read the entire examination. There
Professor: Ian oster Ts: Xuehai Zhang, Yong Zhao Winter Quarter www.classes.cs.uchicago.edu/classes/archive//winter/541-1 alculate the total time required to transfer a 1 KB file (RTT=1 ms, packet size
Computer Networks Ethernet Hubs and Switches Based on Computer Networking, 4 th Edition by Kurose and Ross Ethernet dominant wired LAN technology: cheap $20 for NIC first widely used LAN technology Simpler,
LANs Local Area Networks via the Media Access Control (MAC) SubLayer 1 Local Area Networks Aloha Slotted Aloha CSMA (non-persistent, 1-persistent, p-persistent) CSMA/CD Ethernet Token Ring 2 Network Layer
Introduction Abusayeed Saifullah CS 5600 Computer Networks These slides are adapted from Kurose and Ross Roadmap 1.1 what is the Inter? 1.2 work edge end systems, works, links 1.3 work core packet switching,
TCP over Multi-hop Wireless Networks * Overview of Transmission Control Protocol / Internet Protocol (TCP/IP) *Slides adapted from a talk given by Nitin Vaidya. Wireless Computing and Network Systems Page
Network Protocol Design and Evaluation 08 - Analytical Evaluation Stefan Rührup Summer 2009 Overview In the last chapter: Simulation In this part: Analytical Evaluation: case studies 2 Analytical Evaluation
Computer Networks Delay, loss and throughput Layered architectures How do loss and delay occur? packets queue in router buffers packet arrival rate to exceeds output capacity packets queue, wait for turn
Lecture Today slotted vs unslotted ALOHA Carrier sensing multiple access Ethernet DataLink Layer 1 Random Access Protocols When node has packet to send transmit at full channel data rate R. no a priori
ECE 333: Introduction to Communication Networks Fall 2002 Lecture 14: Medium Access Control II Dynamic Channel Allocation Pure Aloha In the last lecture we began discussing medium access control protocols
PAPER CODE NO. EXAMINER : Martin Gairing COMP211 DEPARTMENT : Computer Science Tel. No. 0151 795 4264 First Semester Examinations 2011/12 INTERNET PRINCIPLES TIME ALLOWED : Two Hours INSTRUCTIONS TO CANDIDATES
Homework Assignment #1 Solutions EE122: Introduction to Communication Networks (Fall 2007) Department of Electrical Engineering and Computer Sciences College of Engineering University of California, Berkeley
Network Performance: Networks must be fast What are the essential network performance metrics: bandwidth and latency Transmission media AS systems Input'signal'f(t) Has'bandwidth'B System'with'H(-) Output'signal'g(t)
CS326e Quiz 3 The first correct 10 answers will be worth 1 point each. Each subsequent correct answer will be worth 0.2 points. Circle the correct answer. UTEID In the following 7 problems, we are sending
Transport Layer Protocols Version. Transport layer performs two main tasks for the application layer by using the network layer. It provides end to end communication between two applications, and implements
CS335 Sample Questions for Exam #2.) Compare connection-oriented with connectionless protocols. What type of protocol is IP? How about TCP and UDP? Connection-oriented protocols Require a setup time to
4. MAC protocols and LANs 1 Outline MAC protocols and sublayers, LANs: Ethernet, Token ring and Token bus Logic Link Control (LLC) sublayer protocol Bridges: transparent (spanning tree), source routing
Part I: The problem specifications NTNU The Norwegian University of Science and Technology Department of Telematics Note! The problem set consists of two parts: Part I: The problem specifications pages
CSE331: Introduction to Networks and Security Lecture 6 Fall 2006 Open Systems Interconnection (OSI) End Host Application Reference model not actual implementation. Transmits messages (e.g. FTP or HTTP)
SC250 Computer Networking I Architecture and Performance of the Internet Prof. Matthias Grossglauser School of Computer and Communication Sciences EPFL http://lcawww.epfl.ch 1 Today's Objectives Understanding
CEN 007C Computer Networks Fundamentals Instructor: Prof. A. Helmy Homework : Network Layer Assigned: Nov. 28 th, 2011. Due Date: Dec 8 th, 2011 (to the TA) 1. ( points) What are the 2 most important network-layer
Part I: The problem specifications NTNU The Norwegian University of Science and Technology Department of Telematics Note! The problem set consists of two parts: Part I: The problem specifications pages
Module 2 Overview of Computer Networks Networks and Communication Give me names of all employees Who earn more than $100,000 % ISP intranet % % % backbone satellite link desktop computer: server: network
Data Link Layer, Part 5 Sliding Window Protocols These slides are created by Dr. Yih Huang of George Mason University. Students registered in Dr. Huang's courses at GMU can make a single machine-readable
EECS 122: Introduction to Computer Networks Multiaccess Protocols Computer Science Division Department of Electrical Engineering and Computer Sciences University of California, Berkeley Berkeley, CA 94720-1776
(International Journal of Computer Science & Management Studies) Vol. 17, Issue 01 Performance Evaluation of AODV, OLSR Routing Protocol in VOIP Over Ad Hoc Dr. Khalid Hamid Bilal Khartoum, Sudan email@example.com
Chapter 1 Review Questions R1. What is the difference between a host and an end system? List several different types of end systems. Is a Web server an end system? 1. There is no difference. Throughout
Lecture 15: Congestion Control CSE 123: Computer Networks Stefan Savage Overview Yesterday: TCP & UDP overview Connection setup Flow control: resource exhaustion at end node Today: Congestion control Resource
TCP PERFORMANCE IN MOBILE-IP Foo Chun Choong Department of Electrical Engineering, National University of Singapore ABSTRACT The throughput performance of TCP in Mobile-IP  was investigated. Compared
Dynamic Source Routing in Ad Hoc Wireless Networks David B. Johnson David A. Maltz Computer Science Department Carnegie Mellon University 5000 Forbes Avenue Pittsburgh, PA 15213-3891 firstname.lastname@example.org Abstract
Spring Term 2014 Operating Systems and Networks Sample Solution 1 1 byte = 8 bits 1 kilobyte = 1024 bytes 10 3 bytes 1 Network Performance 1.1 Delays Given a 1Gbps point to point copper wire (propagation
CSE33: Introduction to Networks and Security Lecture 9 Fall 2006 Announcements Project Due TODAY HW Due on Friday Midterm I will be held next Friday, Oct. 6th. Will cover all course material up to next
.02 Spring 2012, Quiz 3 Page 1 of 11 Name: DEPARTMENT OF EECS MASSACHUSETTS INSTITUTE OF TECHNOLOGY.02 Spring 2012 Quiz III May 22, 2012 your section Section Time Recitation Instructor TA 1 10-11 Vincent
Basic Multiplexing models? Supermarket?? Computer Networks - Vassilis Tsaoussidis Schedule Where does statistical multiplexing differ from TDM and FDM Why are buffers necessary - what is their tradeoff,
White Paper Per-Flow Queuing Allot's Approach to Bandwidth Management Allot Communications, July 2006. All Rights Reserved. Table of Contents Executive Overview... 3 Understanding TCP/IP... 4 What is Bandwidth
Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge 1.3 Network core 1.4 Network access and physical media 1.5 Internet structure and s 1.6 Delay & loss in packet-switched networks 1.7 Protocol
1 Homework 2 assignment for ECE374 Posted: 02/20/15 Due: 02/27/15 ote: In all written assignments, please show as much of your work as you can. Even if you get a wrong answer, you can get partial credit
AN IMPROVED SNOOP FOR TCP RENO AND TCP SACK IN WIRED-CUM- WIRELESS NETWORKS Srikanth Tiyyagura Department of Computer Science and Engineering JNTUA College of Engg., pulivendula, Andhra Pradesh, India.
Tutorial for Chapter 1 CEN 444 Computer Networks Dr. Mostafa Dahshan Department of Computer Engineering College of Computer and Information Sciences King Saud University email@example.com Tutorial for
ICOM 5026-090: Computer Networks Chapter 6: The Transport Layer By Dr Yi Qian Department of Electronic and Computer Engineering Fall 2006 Outline The transport service Elements of transport protocols A
Laboratory 12 Applications Network Application Performance Analysis Objective The objective of this lab is to analyze the performance of an Internet application protocol and its relation to the underlying
Congestion Control When one part of the subnet (e.g. one or more routers in an area) becomes overloaded, congestion results. Because routers are receiving packets faster than they can forward them, one
Data Transfer Consider transferring an enormous file of L bytes from Host A to B using a MSS of 1460 bytes and a 66 byte header. What is the maximum value of L such that TCP sequence numbers are not exhausted?
Optimization of Communication Systems Lecture 6: Internet TCP Congestion Control Professor M. Chiang Electrical Engineering Department, Princeton University ELE539A February 21, 2007 Lecture Outline TCP
Voice over IP Demonstration 1: VoIP Protocols Network Environment We use two Windows workstations from the production network, both with OpenPhone application (figure 1). The OpenH.323 project has developed
CHAPTER 12 PRACTICE SET Questions Q12-1. The answer is CSM/CD. a. CSMA/CD is a random-access protocol. b. Polling is a controlled-access protocol. c. TDMA is a channelization protocol. Q12-3. The answer
Wireless Physical Layer Q1. Is it possible to transmit a digital signal, e.g., coded as square wave as used inside a computer, using radio transmission without any loss? Why? It is not possible to transmit
Internet Firewall CSIS 4222 A combination of hardware and software that isolates an organization s internal network from the Internet at large Ch 27: Internet Routing Ch 30: Packet filtering & firewalls
PART-A Questions 1. Differentiate between internet and intranet. 2. What are the two types of spread spectrum? 3. Define hamming distance. 4. What are carrier sense protocols? 5. What are the two types
Mobile Communications Chapter 9: Mobile Transport Layer Motivation TCP-mechanisms Classical approaches Indirect TCP Snooping TCP Mobile TCP PEPs in general Additional optimizations Fast retransmit/recovery
ISSN: 2321-7782 (Online) Volume 1, Issue 7, December 2013 International Journal of Advance Research in Computer Science and Management Studies Research Paper Available online at: www.ijarcsms.com A Survey:
CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012 Important: The solutions to the homework problems from the course book have been provided by the authors.
Midterm Exam CMPSCI 453: Computer Networks Fall 2011 Prof. Jim Kurose Instructions: There are 4 questions on this exam. Please use two exam blue books answer questions 1, 2 in one book, and the remaining
www.gatehelp.com GATE CS Topic wise Questions YEAR 23 Question. 1 Which of the following assertions is false about the internet Protocol (IP)? (A) It is possible for a computer to have multiple IP addresses
A Comparative Analysis of TCP Tahoe, Reno, New-Reno, SACK and Vegas Abstract: The purpose of this paper is to analyze and compare the different congestion control and avoidance mechanisms which have been
Computer Networks Lecture 06 Connecting Networks Kuang-hua Chen Department of Library and Information Science National Taiwan University Local Area Networks (LAN) 5 kilometer IEEE 802.3 Ethernet IEEE 802.4
TCP over Wireless Networks Raj Jain Professor of Computer Science and Engineering Washington University in Saint Louis Saint Louis, MO 63130 Audio/Video recordings of this lecture are available at: http://www.cse.wustl.edu/~jain/cse574-10/
Multimedia Networking Reading: Sections 3.1.2, 3.3, 4.5, and 6.5 CS-375: Computer Networks Dr. Thomas C. Bressoud 1 Digital Audio and Video Data 2 Challenges for Media Streaming Large volume of data Each
Simulation-Based Comparisons of Solutions for TCP Packet Reordering in Wireless Network 作 者 :Daiqin Yang, Ka-Cheong Leung, and Victor O. K. Li 出 處 :Wireless Communications and Networking Conference, 2007.WCNC
Congestion Control Overview Problem: When too many packets are transmitted through a network, congestion occurs t very high traffic, performance collapses completely, and almost no packets are delivered
Homework 3 1 DNS Suppose you have a Host C, a local name server L, and authoritative name servers A root, A com, and A google.com, where the naming convention A x means that the name server knows about
Introduction Computer Network. Interconnected collection of autonomous computers that are able to exchange information No master/slave relationship between the computers in the network Data Communications.
TCP Westwood for Wireless מבוא רקע טכני בקרת עומס ב- TCP TCP על קשר אלחוטי שיפור תפוקה עם פרוטוקול TCP Westwood סיכום.184.108.40.206.5 Seminar in Computer Networks and Distributed Systems Hadassah College Spring
Lecture 2 : The DSDV Protocol Lecture 2.1 : The Distributed Bellman-Ford Algorithm Lecture 2.2 : The Destination Sequenced Distance Vector (DSDV) protocol The Routing Problem S S D D The routing problem
EECS 489 Winter 2010 Midterm Exam Name: This is an open-book, open-resources exam. Explain or show your work for each question. Your grade will be severely deducted if you don t show your work, even if
1. Local Area Networks TCOM 370 NOTES 99-12 LOCAL AREA NETWORKS AND THE ALOHA PROTOCOL These are networks spanning relatively short distances (e.g. within one building) for local point-to-point and point-to-multipoint
Names & Addresses EE 122: IP Forwarding and Transport Protocols Scott Shenker http://inst.eecs.berkeley.edu/~ee122/ (Materials with thanks to Vern Paxson, Jennifer Rexford, and colleagues at UC Berkeley)