# First Midterm for ECE374 02/25/15 Solution!!

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 1 First Midterm for ECE374 02/25/15 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam taker - if you get stuck on one problem go on to another problem. Also, don't waste your time giving irrelevant (or not requested) details. The total number of points for each question is given in parenthesis. There are 100 points total. An approximate amount of time that would be reasonable to spend on each question is also given; if you follow the suggested time guidelines, you should finish with 10 minutes to spare. The exam is 90 minutes long. Show all your work. Partial credit is possible for an answer, but only if you show the intermediate steps in obtaining the answer. If you make a mistake, it will also help the grader show you where you made a mistake. Good luck. Problem Max. Points Points Total 100

3 3 caches will not query into the system for and hence would not learn the new mapping. g. Explain why you can actually use the telnet protocol to perform a simple communication with a web server? Answer: Telnet is a text- based communication protocol, likewise is HTTP. If a client composes a text message that is HTTP standard compliant the server sends back the expected reply, which is shown in text (including the HTML content at the client. h. Assume that in the case of a pipelined, reliable transport protocol, for which the sender can have up to N=4 unacknowleged packets, packets with sequence numbers 0-3 are transmitted. Only the packet with sequence number 2 gets lost during the transmission. What are the sequence numbers of the packets that are retransmitted in the case of Go-Back-N? What are they in the case of Selective Repeat? Answer: Go-Back-N: 2, 3; Selective Repeat: 2. Problem 2: Delays, Throughput (24 Points, 20 minutes) Figure 1 Consider the network shown in Figure 1. a. (4 Points) Based on this figure explain how the traceroute application determines the round- trip- time (RTT) between your host, the individual routers on the path to the receiving host, and the receiving host? A: sends three packets that will reach router i on path towards destination, router i will return packets to sender, sender times interval between transmission and reply. b. (2 Points) The following line represents a typical single output line from traceroute: ar01.needham.ma.boston.comcast.net( ) ms ms ms Why do the values for the three RTTs shown at the end of that line change? Answer: RTTs highly depend on the queue length of the routers located between the sender and the receiver. Based on other traffic there can be more or less waiting packets in a routers outgoing queue at a certain instance in time. Thus, the RTT between individual pings can vary. c. (4 Points) Now assume a static RTT of 136 milliseconds between the two hosts. How long will it take in this case of an HTTP GET request to receive the first bit of the HTTP response from Host B? How long will it take to transmit

7 7 Problem 4: Transport Protocols (24 Points, 25 minutes) a. (14 Points) Consider a scenario in which Host A wants to simultaneously send packets to Hosts B and C via a broadcast channel - a packet sent by A is carried by the channel to both B and C. Suppose that the broadcast channel connecting A, B, and C can independently lose and corrupt packets (for example, a packet sent from A might be correctly received by B, but not by C). Design a stop- and- wait like error control protocol for reliably transferring packets from A to B and C, such that A will not get new data from the upper layer until it knows that both B and C have correctly received the current packet. Give FSM descriptions of A and C. (Hint: The FSM for B should be essentially the same as for C.) Also, give a description of the packet format(s) used. Answer:

8 8 b. (4 Points) rdt3.0 in action! For this problem assume the reliable, error- correcting stop and wait protocol rdt3.0. Figure 4 shows the initial communication between sender and receiver. In this example, the packet with sequence number 1 is lost on the way to the receiver. Complete Figure 4 to illustrate how rdt3.0 recovers from that packet loss by illustrating the (error- free) transmission of 2 additional packets. Figure 4

9 9 Answer: c. (4 Points) In the rdt 3.0 protocol the ACKs flowing from the receiver to the sender do NOT have sequence numbers (although they do have an ACK field that contains the sequence number of the packet they are acknowledging). Why is it that the ACKs do not require sequence numbers? (Hint: Think about the case of duplicated ACKs.) Answer: To best answer this question, consider why we needed sequence numbers in the first place. We saw that the sender needs sequence numbers so that the receiver can tell if a data packet is a duplicate of an already received data packet. In the case of ACKs, the sender does not need this info (i.e., a sequence number on an ACK) to tell detect a duplicate ACK. A duplicate ACK is obvious to the rdt3.0 receiver, since when it has received the original ACK it transitioned to the next state. The duplicate ACK is not the ACK that the sender needs and hence is ignored by the rdt3.0 sender. d. (2 Points) Figure 5 shows the trace operation of a pipelined protocol. Does it show the trace of Go- Back- N or Selective Repeat?

10 10 Figure 5 Answer: Go- Back- N

### First Midterm for ECE374 03/09/12 Solution!!

1 First Midterm for ECE374 03/09/12 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam

### Final for ECE374 05/06/13 Solution!!

1 Final for ECE374 05/06/13 Solution!! Instructions: Put your name and student number on each sheet of paper! The exam is closed book. You have 90 minutes to complete the exam. Be a smart exam taker -

### Homework 2 assignment for ECE374 Posted: 02/21/14 Due: 02/28/14

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

### First Midterm for ECE374 03/24/11 Solution!!

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

### Midterm Exam CMPSCI 453: Computer Networks Fall 2011 Prof. Jim Kurose

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

### Homework 2 assignment for ECE374 Posted: 02/20/15 Due: 02/27/15

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

### Computer Networks - CS132/EECS148 - Spring 2013 ------------------------------------------------------------------------------

Computer Networks - CS132/EECS148 - Spring 2013 Instructor: Karim El Defrawy Assignment 2 Deadline : April 25 th 9:30pm (hard and soft copies required) ------------------------------------------------------------------------------

### COMP 361 Computer Communications Networks. Fall Semester 2003. Midterm Examination

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

### Referring to the above question, the end-to-end delay (transmission delay plus propagation delay) is

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

### Computer Networks Homework 1

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.

### Answer: that dprop equals dtrans. seconds. a) d prop. b) d trans

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

### R2. The word protocol is often used to describe diplomatic relations. How does Wikipedia describe diplomatic protocol?

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

### CSE 473 Introduction to Computer Networks. Exam 2 Solutions. Your name: 10/31/2013

CSE 473 Introduction to Computer Networks Jon Turner Exam Solutions Your name: 0/3/03. (0 points). Consider a circular DHT with 7 nodes numbered 0,,...,6, where the nodes cache key-values pairs for 60

### Data Networks Summer 2007 Homework #3

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.

### Introduction. Abusayeed Saifullah. CS 5600 Computer Networks. These slides are adapted from Kurose and Ross

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,

### Operating Systems and Networks Sample Solution 1

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

### Transport Layer Protocols

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

### Architecture and Performance of the Internet

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

### >>> SOLUTIONS <<< c) The OSI Reference Model has two additional layers. Where are these layers in the stack and what services do they provide?

Midterm Exam for Computer Networks (CNT 4004) Fall 2013 >>> SOLUTIONS

### Delay, loss, layered architectures. packets queue in router buffers. packets queueing (delay)

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

### Computer Networks - CS132/EECS148 - Spring 2013 ------------------------------------------------------------------------------

Computer Networks - CS132/EECS148 - Spring 2013 Instructor: Karim El Defrawy Assignment 3 - Solutions Deadline : May 9 th 9:30pm (hard and soft copies required) ------------------------------------------------------------------------------

### ECE/CS 372 introduction to computer networks. Lecture 2. Midterm scheduled for Tuesday, May 7 th

ECE/CS 372 introduction to computer networks Lecture 2 Announcements: Please make sure to check the course s website on a regular basis http://web.engr.oregonstate.edu/~sinkyha/cs372 Midterm scheduled

### EECS 489 Winter 2010 Midterm Exam

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

### Computer Networks & Security 2014/2015

Computer Networks & Security 2014/2015 IP Protocol Stack & Application Layer (02a) Security and Embedded Networked Systems time Protocols A human analogy All Internet communication is governed by protocols!

### Stop And Wait. ACK received; transmit frame 2 CS 455 3

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

### THE UNIVERSITY OF AUCKLAND

COMPSCI 742 THE UNIVERSITY OF AUCKLAND SECOND SEMESTER, 2008 Campus: City COMPUTER SCIENCE Data Communications and Networks (Time allowed: TWO hours) NOTE: Attempt all questions. Calculators are NOT permitted.

### Note! The problem set consists of two parts: Part I: The problem specifications pages Part II: The answer pages

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

### Prefix AggregaNon. Company X and Company Y connect to the same ISP, and they are assigned the prefixes:

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?

### Lab 2. CS-335a. Fall 2012 Computer Science Department. Manolis Surligas surligas@csd.uoc.gr

Lab 2 CS-335a Fall 2012 Computer Science Department Manolis Surligas surligas@csd.uoc.gr 1 Summary At this lab we will cover: Basics of Transport Layer (TCP, UDP) Broadcast ARP DNS More Wireshark filters

### Internet Firewall CSIS 4222. Packet Filtering. Internet Firewall. Examples. Spring 2011 CSIS 4222. net15 1. Routers can implement packet filtering

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

### Key Components of WAN Optimization Controller Functionality

Key Components of WAN Optimization Controller Functionality Introduction and Goals One of the key challenges facing IT organizations relative to application and service delivery is ensuring that the applications

### CH.1. Lecture # 2. Computer Networks and the Internet. Eng. Wafaa Audah. Islamic University of Gaza. Faculty of Engineering

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

### Note! The problem set consists of two parts: Part I: The problem specifications pages Part II: The answer pages

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

### Sage 300 ERP Online. Mac Resource Guide. (Formerly Sage ERP Accpac Online) Updated June 1, 2012. Page 1

Sage 300 ERP Online (Formerly Sage ERP Accpac Online) Mac Resource Guide Updated June 1, 2012 Page 1 Table of Contents 1.0 Introduction... 3 2.0 Getting Started with Sage 300 ERP Online using a Mac....

### Sage ERP Accpac Online

Sage ERP Accpac Online Mac Resource Guide Thank you for choosing Sage ERP Accpac Online. This Resource Guide will provide important information and instructions on how you can get started using your Mac

### Using IPM to Measure Network Performance

CHAPTER 3 Using IPM to Measure Network Performance This chapter provides details on using IPM to measure latency, jitter, availability, packet loss, and errors. It includes the following sections: Measuring

### Network Performance: Networks must be fast. What are the essential network performance metrics: bandwidth and latency

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)

### Applications. Network Application Performance Analysis. Laboratory. Objective. Overview

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

### CS640: Introduction to Computer Networks. Applications FTP: The File Transfer Protocol

CS640: Introduction to Computer Networks Aditya Akella Lecture 4 - Application Protocols, Performance Applications FTP: The File Transfer Protocol user at host FTP FTP user client interface local file

### 15-441: Computer Networks Homework 2 Solution

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

### Datagram-based network layer: forwarding; routing. Additional function of VCbased network layer: call setup.

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

### CS268 Exam Solutions. 1) End-to-End (20 pts)

CS268 Exam Solutions General comments: ) If you would like a re-grade, submit in email a complete explanation of why your solution should be re-graded. Quote parts of your solution if necessary. In person

HW2 Grade 70 60 CS585: Applications 50 40 30 20 0 0 2 3 4 5 6 7 8 9 0234567892022223242526272829303323334353637383940442 CS585\CS485\ECE440 Fall 2009 Traditional Applications SMTP Simple Mail Transfer

### Names & Addresses. Names & Addresses. Hop-by-Hop Packet Forwarding. Longest-Prefix-Match Forwarding. Longest-Prefix-Match Forwarding

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)

### Network Layers. CSC358 - Introduction to Computer Networks

Network Layers Goal Understand how application processes set up a connection and exchange messages. Understand how addresses are determined Data Exchange Between Application Processes TCP Connection-Setup

### EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Mathematics and Computer Science

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

### Overview of Network Hardware and Software. CS158a Chris Pollett Jan 29, 2007.

Overview of Network Hardware and Software CS158a Chris Pollett Jan 29, 2007. Outline Scales of Networks Protocol Hierarchies Scales of Networks Last day, we talked about broadcast versus point-to-point

### ECE 358: Computer Networks. Solutions to Homework #4. Chapter 4 - The Network Layer

ECE 358: Computer Networks Solutions to Homework #4 Chapter 4 - The Network Layer P 4. Consider the network below. a. Suppose that this network is a datagram network. Show the forwarding table in router

### GATE CS Topic wise Questions Computer Network

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

### TCP over Multi-hop Wireless Networks * Overview of Transmission Control Protocol / Internet Protocol (TCP/IP) Internet Protocol (IP)

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 Security: Workshop. Dr. Anat Bremler-Barr. Assignment #2 Analyze dump files Solution Taken from www.chrissanders.org

1.pcap - File download Network Security: Workshop Dr. Anat Bremler-Barr Assignment #2 Analyze dump files Solution Taken from www.chrissanders.org Downloading a file is a pretty basic function when described

### The exam has 110 possible points, 10 of which are extra credit. There is a Word Bank on Page 8. Pages 7-8 can be removed from the exam.

CS326e Spring 2014 Midterm Exam Name SOLUTIONS UTEID The exam has 110 possible points, 10 of which are extra credit. There is a Word Bank on Page 8. Pages 7-8 can be removed from the exam. 1. [4 Points]

### CS 5480/6480: Computer Networks Spring 2012 Homework 1 Solutions Due by 9:00 AM MT on January 31 st 2012

CS 5480/6480: Computer Networks Spring 2012 Homework 1 Solutions Due by 9:00 AM MT on January 31 st 2012 Important: No cheating will be tolerated. No extension. CS 5480 total points = 32 CS 6480 total

### CS 5480/6480: Computer Networks Spring 2012 Homework 4 Solutions Due by 1:25 PM on April 11 th 2012

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.

### 1. The Web: HTTP; file transfer: FTP; remote login: Telnet; Network News: NNTP; e-mail: SMTP.

Chapter 2 Review Questions 1. The Web: HTTP; file transfer: FTP; remote login: Telnet; Network News: NNTP; e-mail: SMTP. 2. Network architecture refers to the organization of the communication process

### Improving the Performance of TCP Using Window Adjustment Procedure and Bandwidth Estimation

Improving the Performance of TCP Using Window Adjustment Procedure and Bandwidth Estimation R.Navaneethakrishnan Assistant Professor (SG) Bharathiyar College of Engineering and Technology, Karaikal, India.

### File Transfer Protocol (FTP) Throughput Testing by Rachel Weiss

White Paper File Transfer Protocol (FTP) Throughput Testing by Rachel Weiss Introduction In today s complex networks it is often difficult to correlate different measurements that are reported by network

### Internet structure: network of networks

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

### Exam 1 Review Questions

CSE 473 Introduction to Computer Networks Exam 1 Review Questions Jon Turner 10/2013 1. A user in St. Louis, connected to the internet via a 20 Mb/s (b=bits) connection retrieves a 250 KB (B=bytes) web

### LESSON 3.6. 98-366 Networking Fundamentals. Understand TCP/IP

Understand TCP/IP Lesson Overview In this lesson, you will learn about: TCP/IP Tracert Telnet Netstat Reserved addresses Local loopback IP Ping Pathping Ipconfig Protocols Anticipatory Set Experiment with

### APPENDIX 1 USER LEVEL IMPLEMENTATION OF PPATPAN IN LINUX SYSTEM

152 APPENDIX 1 USER LEVEL IMPLEMENTATION OF PPATPAN IN LINUX SYSTEM A1.1 INTRODUCTION PPATPAN is implemented in a test bed with five Linux system arranged in a multihop topology. The system is implemented

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

### Homework Assignment #3 Due 11/20 at 5:00pm EE122 Fall 2012

Homework Assignment #3 Due 11/20 at 5:00pm EE122 Fall 2012 Please submit your solutions using BSpace (https://bspace.berkeley.edu/). Log in to BSpace with your CalNet ID, click on the EL ENG 122 Fa12 tab,

### Professor: Ian Foster TAs: Xuehai Zhang, Yong Zhao. Winter Quarter. www.classes.cs.uchicago.edu/classes/archive/2003/winter/54001-1

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

### What is Network Latency and Why Does It Matter?

What is Network Latency and Why Does It Matter? by O3b Networks This paper is presented by O3b Networks to provide clarity and understanding of a commonly misunderstood facet of data communications known

### TCP and Wireless Networks Classical Approaches Optimizations TCP for 2.5G/3G Systems. Lehrstuhl für Informatik 4 Kommunikation und verteilte Systeme

Chapter 2 Technical Basics: Layer 1 Methods for Medium Access: Layer 2 Chapter 3 Wireless Networks: Bluetooth, WLAN, WirelessMAN, WirelessWAN Mobile Networks: GSM, GPRS, UMTS Chapter 4 Mobility on the

### Application. Transport. Network. Data Link. Physical. Network Layers. Goal

Layers Goal Understand how application processes set up a connection and exchange messages. Understand how addresses are determined 1 2 Data Exchange Between Processes TCP Connection-Setup Between Processes

### Communications and Networking

Communications and Networking History and Background telephone system local area networks Internet architecture: what the pieces are and how they fit together names and addresses: what's your name and

### Application Layer. CMPT371 12-1 Application Layer 1. Required Reading: Chapter 2 of the text book. Outline of Chapter 2

CMPT371 12-1 Application Layer 1 Application Layer Required Reading: Chapter 2 of the text book. Outline of Chapter 2 Network applications HTTP, protocol for web application FTP, file transfer protocol

### CSE 123: Computer Networks

CSE 123: Computer Networks Homework 4 Solutions Out: 12/03 Due: 12/10 1. Routers and QoS Packet # Size Flow 1 100 1 2 110 1 3 50 1 4 160 2 5 80 2 6 240 2 7 90 3 8 180 3 Suppose a router has three input

### STANDPOINT FOR QUALITY-OF-SERVICE MEASUREMENT

STANDPOINT FOR QUALITY-OF-SERVICE MEASUREMENT 1. TIMING ACCURACY The accurate multi-point measurements require accurate synchronization of clocks of the measurement devices. If for example time stamps

### Solutions to the Sample Questions on Introduction

Solutions to the Sample Questions on Introduction NOTE: Pay close attention to units. A byte of storage is 8-bits, and 1 kilobits of storage is1024 bits. By convention, the rules are different between

### Introduction to LAN/WAN. Network Layer

Introduction to LAN/WAN Network Layer Topics Introduction (5-5.1) Routing (5.2) (The core) Internetworking (5.5) Congestion Control (5.3) Network Layer Design Isues Store-and-Forward Packet Switching Services

### Mobile Communications Chapter 9: Mobile Transport Layer

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

### Life of a Packet CS 640, 2015-01-22

Life of a Packet CS 640, 2015-01-22 Outline Recap: building blocks Application to application communication Process to process communication Host to host communication Announcements Syllabus Should have

### CS551 End-to-End Internet Packet Dynamics [Paxson99b]

CS551 End-to-End Internet Packet Dynamics [Paxson99b] Bill Cheng http://merlot.usc.edu/cs551-f12 1 End-to-end Packet Dynamics How do you measure Internet performance? Why do people want to know? Are ISPs

### TCP/IP Protocol Suite. Marshal Miller Chris Chase

TCP/IP Protocol Suite Marshal Miller Chris Chase Robert W. Taylor (Director of Information Processing Techniques Office at ARPA 1965-1969) "For each of these three terminals, I had three different sets

### Computer Networks. Chapter 5 Transport Protocols

Computer Networks Chapter 5 Transport Protocols Transport Protocol Provides end-to-end transport Hides the network details Transport protocol or service (TS) offers: Different types of services QoS Data

### CSE3214 Computer Network Protocols and Applications. Chapter 1 Examples and Homework Problems

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 COMMUNICATIONS AND NETWORKING. Solved Examples

Page 1 of 10 DATA COMMUNICATIONS AND NETWORKING Solved Examples References: STA: Stallings, Data and Computer Communications, 6 th ed. TAN: Tannenbaum, Computer Networks, 4 th ed.) 1. Given the following

### Low-rate TCP-targeted Denial of Service Attack Defense

Low-rate TCP-targeted Denial of Service Attack Defense Johnny Tsao Petros Efstathopoulos University of California, Los Angeles, Computer Science Department Los Angeles, CA E-mail: {johnny5t, pefstath}@cs.ucla.edu

### Agenda. Distributed System Structures. Why Distributed Systems? Motivation

Agenda Distributed System Structures CSCI 444/544 Operating Systems Fall 2008 Motivation Network structure Fundamental network services Sockets and ports Client/server model Remote Procedure Call (RPC)

### Alteon Global Server Load Balancing

Alteon Global Server Load Balancing Whitepaper GSLB Operation Overview Major Components Distributed Site Monitoring Distributed Site State Protocol Internet Topology Awareness DNS Authoritative Name Server

### ECE 333: Introduction to Communication Networks Fall 2002

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

### Lecture 15: Congestion Control. CSE 123: Computer Networks Stefan Savage

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

### Procedure: You can find the problem sheet on Drive D: of the lab PCs. 1. IP address for this host computer 2. Subnet mask 3. Default gateway address

Objectives University of Jordan Faculty of Engineering & Technology Computer Engineering Department Computer Networks Laboratory 907528 Lab.4 Basic Network Operation and Troubleshooting 1. To become familiar

### The Application Layer: DNS

Recap SMTP and email The Application Layer: DNS Smith College, CSC 9 Sept 9, 0 q SMTP process (with handshaking) and message format q Role of user agent access protocols q Port Numbers (can google this)

### EKSAMEN / EXAM TTM4100 18 05 2007

1.1 1.1.1...... 1.1.2...... 1.1.3...... 1.1.4...... 1.1.5...... 1.1.6...... 1.1.7...... 1.1.8...... 1.1.9...... 1.1.10.... 1.1.11... 1.1.16.... 1.1.12... 1.1.17.... 1.1.13... 1.1.18.... 1.1.14... 1.1.19....

### Network Security. Vorlesung Kommunikation und Netze SS 10 E. Nett

Network Security Internet not originally designed with (much) security in mind original vision: a group of mutually trusting users attached to a transparent network Security considerations in all layers!

### Technical Support Information Belkin internal use only

The fundamentals of TCP/IP networking TCP/IP (Transmission Control Protocol / Internet Protocols) is a set of networking protocols that is used for communication on the Internet and on many other networks.

### What communication protocols are used to discover Tesira servers on a network?

Understanding device discovery methods in Tesira OBJECTIVES In this application note, basic networking concepts will be summarized to better understand how Tesira servers are discovered over networks.

### Networking Overview. (as usual, thanks to Dave Wagner and Vern Paxson)

Networking Overview (as usual, thanks to Dave Wagner and Vern Paxson) Focus For This Lecture Sufficient background in networking to then explore security issues in next few lectures Networking = the Internet

### TCP in Wireless Mobile Networks

TCP in Wireless Mobile Networks 1 Outline Introduction to transport layer Introduction to TCP (Internet) congestion control Congestion control in wireless networks 2 Transport Layer v.s. Network Layer

### 15-441: Computer Networks Homework 1

15-441: Computer Networks Homework 1 Assigned: September 9 / 2002. Due: September 18 / 2002 in class. In this homework you will run various useful network tools that are available in the Sun/Solaris machines

### COMP 3331/9331: Computer Networks and Applications. Lab Exercise 3: TCP and UDP (Solutions)

COMP 3331/9331: Computer Networks and Applications Lab Exercise 3: TCP and UDP (Solutions) AIM To investigate the behaviour of TCP and UDP in greater detail. EXPERIMENT 1: Understanding TCP Basics Tools

### Voice over IP. Demonstration 1: VoIP Protocols. Network Environment

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

### Protocols. Packets. What's in an IP packet

Protocols Precise rules that govern communication between two parties TCP/IP: the basic Internet protocols IP: Internet Protocol (bottom level) all packets shipped from network to network as IP packets