# The following reference answers are based on the trace files provided with the text book, which can be downloaded from the textbook website.

Size: px
Start display at page:

Download "The following reference answers are based on the trace files provided with the text book, which can be downloaded from the textbook website."

## Transcription

2 2. (1 point) What is the sequence number of the TCP SYN segment that is used to initiate the TCP connection between the client computer and gaia.cs.umass.edu? What is it in the segment that identifies the segment as a SYN segment? Solution: Sequence number of the TCP SYN segment is used to initiate the TCP connection between the client computer and gaia.cs.umass.edu. The value is 0 in this trace. The SYN flag is set to 1 and it indicates that this segment is a SYN segment. Figure 2: Sequence number of the TCP SYN segment 3. (2 points) What is the sequence number of the SYNACK segment sent by gaia.cs.umass.edu to the client computer in reply to the SYN? What is the value of the ACKnowledgement field in the SYNACK segment? How did gaia.cs.umass.edu determine that value? What is it in the segment that identifies the segment as a SYNACK segment? Solution: Sequence number of the SYNACK segment from gaia.cs.umass.edu to the client computer in reply to the SYN has the value of 0 in this trace. 2

3 The value of the ACKnowledgement field in the SYNACK segment is 1. The value of the ACKnowledgement field in the SYNACK segment is determined by gaia.cs.umass.edu by adding 1 to the initial sequence number of SYN segment from the client computer (i.e. the sequence number of the SYN segment initiated by the client computer is 0.). The SYN flag and Acknowledgement flag in the segment are set to 1 and they indicate that this segment is a SYNACK segment. Figure 3: Sequence number and Acknowledgement number of the SYNACK segment 4. (1 point) What is the sequence number of the TCP segment containing the HTTP POST command? Note that in order to find the POST command, you ll need to dig into the packet content field at the bottom of the Wireshark window, looking for a segment with a POST within its DATA field. Solution: No. 4 segment is the TCP segment containing the HTTP POST command. The sequence number of this segment has the value of 1. 3

4 Figure 4: Sequence number of the TCP segment containing the HTTP POST command 5. (2 points) Consider the TCP segment containing the HTTP POST as the first segment in the TCP connection. What are the sequence numbers of the first six segments in the TCP connection (including the segment containing the HTTP POST)? At what time was each segment sent? When was the ACK for each segment received? Given the difference between when each TCP segment was sent, and when its acknowledgement was received, what is the RTT value for each of the six segments? What is the EstimatedRTT value (see page 237 in text) after the receipt of each ACK? Assume that the value of the EstimatedRTT is equal to the measured RTT for the first segment, and then is computed using the EstimatedRTT equation on page 249 for all subsequent segments. Note: Wireshark has a nice feature that allows you to plot the RTT for each of the TCP segments sent. Select a TCP segment in the listing of captured packets window that is being sent from the client to the gaia.cs.umass.edu server. Then select: Statistics->TCP Stream Graph- >Round Trip Time Graph. Solution: The HTTP POST segment is considered as the first segment. Segments 1 6 are No. 4, 5, 7, 8, 10, and 11 in this trace respectively. The ACKs of segments 1 6 are No. 6, 9, 12, 14, 15, and 16 in this trace. 4

5 Segment 1 sequence number: 1 Segment 2 sequence number: 566 Segment 3 sequence number: 2026 Segment 4 sequence number: 3486 Segment 5 sequence number: 4946 Segment 6 sequence number: 6406 The sending time and the received time of ACKs are tabulated in the following table. Sent time ACK received time RTT (seconds) Segment Segment Segment Segment Segment Segment EstimatedRTT = * EstimatedRTT * SampleRTT EstimatedRTT after the receipt of the ACK of segment 1: EstimatedRTT = RTT for Segment 1 = second EstimatedRTT after the receipt of the ACK of segment 2: EstimatedRTT = * * = EstimatedRTT after the receipt of the ACK of segment 3: EstimatedRTT = * * = EstimatedRTT after the receipt of the ACK of segment 4: EstimatedRTT = * * = EstimatedRTT after the receipt of the ACK of segment 5: EstimatedRTT = * * = EstimatedRTT after the receipt of the ACK of segment 6: EstimatedRTT = * * = second 5

6 Figure 5: Segments 1 6 Figure 6: ACKs of segments 1-6 6

7 Figure 7: Round Trip Time Graph 7

8 6. (1 point) What is the length of each of the first six TCP segments? Solution: Length of the first TCP segment (containing the HTTP POST): 565 bytes Length of each of the other five TCP segments: 1460 bytes (MSS) Figure 8: Lengths of segments 1-6 8

10 8. (1 point) Are there any retransmitted segments in the trace file? What did you check for (in the trace) in order to answer this question? Solution: There are no retransmitted segments in the trace file. We can verify this by checking the sequence numbers of the TCP segments in the trace file. In the Time- Sequence-Graph (Stevens) of this trace, all sequence numbers from the source ( ) to the destination ( ) are increasing monotonically with respect to time. If there is a retransmitted segment, the sequence number of this retransmitted segment should be smaller than those of its neighboring segments. Figure 10: Sequence numbers of the segments from the source ( ) to the destination ( ) 10

11 9. (1 point) How much data does the receiver typically acknowledge in an ACK? Can you identify cases where the receiver is ACKing every other received segment (see Table 3.2 on page 257 in the text). Solution: The acknowledged sequence numbers of the ACKs are listed as follows. acknowledged sequence number acknowledged data ACK ACK ACK ACK ACK ACK ACK ACK ACK ACK ACK ACK The difference between the acknowledged sequence numbers of two consecutive ACKs indicates the data received by the server between these two ACKs. By inspecting the amount of acknowledged data by each ACK, there are cases where the receiver is ACKing every other segment. For example, segment of No. 80 acknowledged data with 2920 bytes = 1460*2 bytes. 11

12 Figure 8: Cumulative ACKs (No. 80, 87, 88, etc) where the receiver is ACKing every other received segment. 10. (2 points) What is the throughput (bytes transferred per unit time) for the TCP connection? Explain how you calculated this value. Solution: The computation of TCP throughput largely depends on the selection of averaging time period. As a common throughput computation, in this question, we select the average time period as the whole connection time. Then, the average throughput for this TCP connection is computed as the ratio between the total amount data and the total transmission time. The total amount data transmitted can be computed by the difference between the sequence number of the first TCP segment (i.e. 1 byte for No. 4 segment) and the acknowledged sequence number of the last ACK ( bytes for No. 202 segment). Therefore, the total data are = bytes. The whole transmission time is the difference of the time instant of the first TCP segment (i.e., second for No.4 segment) and the time instant of the last ACK (i.e., second for No. 202 segment). Therefore, the total transmission time is = seconds. Hence, the throughput for the TCP connection is computed as / = KByte/sec. 12

13 11. (2 points) Use the Time-Sequence-Graph (Stevens) plotting tool to view the sequence number versus time plot of segments being sent from the client to the gaia.cs.umass.edu server. Can you identify where TCP s slowstart phase begins and ends, and where congestion avoidance takes over? Solution: TCP Slow Start begins at the start of the connection, i.e., when the HTTP POST segment is sent out. The identification of the TCP slow start phase and congestion avoidance phase depends on the value of the congestion window size of this TCP sender. However, the value of the congestion window size cannot be obtained directly from the Time-Sequence-Graph (Stevens) graph. Nevertheless, we can estimate the lower bound of the TCP window size by the amount of outstanding data because the outstanding data is the amount of data without acknowledgement. We also know that TCP window is constrained by the receiver window size and the receiver buffer can act as the upper bound of the TCP window size. In this trace, the receiver buffer is not the bottleneck; therefore, this upper bound is not quite useful to infer the TCP window size. Hence, we focus on the lower bound of the TCP window size. From the following table, we cannot see that the amount outstanding data increases quickly at the start of this TCP flow; however, it never exceeds 8192 Bytes. Therefore, we can ensure that the TCP window size is larger than 8192 Bytes. Nevertheless, we cannot determine the end of the slow start phase and the start of the congestion avoidance phase for this trace. The major reason is that this TCP sender is not sending data aggressively enough to push to the congestion state. By inspecting the amount of outstanding data, we can observe that the application at most sends out a data block of 8192 bytes. Before it receives the acknowledgement for the whole block of these 8192 bytes, the application will not send more data. It indicates before the end of the slow start phase, the application already stops transmission temporally. 13

14 Type No. Seq. ACKed seq. Outstanding data Data Data ACK Data Data ACK Data Data ACK Data ACK ACK ACK ACK Data Data Data Data Data Data ACK ACK ACK ACK ACK ACK Data Data Data Data Data Data ACK ACK ACK ACK ACK ACK Data Data Data Data

15 Data Data ACK ACK ACK ACK ACK Data Data Data Data Data Data ACK ACK ACK ACK Data Data Data Data Data Data ACK ACK ACK Data Data Data Data Data Data ACK ACK ACK Data Note that the criteria to determine the end of slow start and the beginning of the congestion avoidance is the way how congestion window size reacts to the arrival of ACKs. Upon an ACK arrival, if the congestion window size increases by one MSS, TCP sender still stays in the slow start phase. In the congestion avoidance phase, the congestion window size increases at 1/(current_congestion_window_size). By inspecting the change of the congestion window upon the arrival of ACKs, we can infer the states of the TCP sender. 15

16 12. (2 points) Comment on ways in which the measured data differs from the idealized behavior of TCP that we ve studied in the text. Solution: The idealized behavior of TCP in the text assumes that TCP senders are aggressive in sending data. Too much traffic may congest the network; therefore, TCP senders should follow the AIMD algorithm so that when they detect network congestion (i.e., packet loss), their sending window size should drop down. In the practice, TCP behavior also largely depends on the application. In this example, when the TCP sender can send out data, there are no data available for transmission. In the web application, some of web objects have very small sizes. Before the end of slow start phase, the transmission is over; hence, the transmission of these small web objects suffers from the unnecessary long delay because of the slow start phase of TCP. 16

### This sequence diagram was generated with EventStudio System Designer (http://www.eventhelix.com/eventstudio).

Client App Network Server App 25-May-13 15:32 (Page 1) This sequence diagram was generated with EventStudio System Designer (http://www.eventhelix.com/eventstudio). TCP is an end to end protocol which

### 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.

### 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

### 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

### Improving Effective WAN Throughput for Large Data Flows By Peter Sevcik and Rebecca Wetzel November 2008

Improving Effective WAN Throughput for Large Data Flows By Peter Sevcik and Rebecca Wetzel November 2008 When you buy a broadband Wide Area Network (WAN) you want to put the entire bandwidth capacity to

### PSM-throttling: Minimizing Energy Consumption for Bulk Data Communications in WLANs

PSM-throttling: Minimizing Energy Consumption for Bulk Data Communications in WLANs Xiaodong Zhang Ohio State University in Collaborations with Enhua Tan, Ohio State Lei Guo, Yahoo! Songqing Chen, George

### MONITORING OF TRAFFIC OVER THE VICTIM UNDER TCP SYN FLOOD IN A LAN

MONITORING OF TRAFFIC OVER THE VICTIM UNDER TCP SYN FLOOD IN A LAN Kanika 1, Renuka Goyal 2, Gurmeet Kaur 3 1 M.Tech Scholar, Computer Science and Technology, Central University of Punjab, Punjab, India

### Access Control: Firewalls (1)

Access Control: Firewalls (1) World is divided in good and bad guys ---> access control (security checks) at a single point of entry/exit: in medieval castles: drawbridge in corporate buildings: security/reception

### CYBER ATTACKS EXPLAINED: PACKET CRAFTING

CYBER ATTACKS EXPLAINED: PACKET CRAFTING Protect your FOSS-based IT infrastructure from packet crafting by learning more about it. In the previous articles in this series, we explored common infrastructure

### 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

### Ina Minei Reuven Cohen. The Technion. Haifa 32000, Israel. e-mail: faminei,rcoheng@cs.technion.ac.il. Abstract

High Speed Internet Access Through Unidirectional Geostationary Satellite Channels Ina Minei Reuven Cohen Computer Science Department The Technion Haifa 32000, Israel e-mail: faminei,rcoheng@cs.technion.ac.il

### Attack Lab: Attacks on TCP/IP Protocols

Laboratory for Computer Security Education 1 Attack Lab: Attacks on TCP/IP Protocols Copyright c 2006-2010 Wenliang Du, Syracuse University. The development of this document is funded by the National Science

### Load Balancing. Final Network Exam LSNAT. Sommaire. How works a "traditional" NAT? Un article de Le wiki des TPs RSM.

Load Balancing Un article de Le wiki des TPs RSM. PC Final Network Exam Sommaire 1 LSNAT 1.1 Deployement of LSNAT in a globally unique address space (LS-NAT) 1.2 Operation of LSNAT in conjunction with

### Enabling Cloud Architecture for Globally Distributed Applications

The increasingly on demand nature of enterprise and consumer services is driving more companies to execute business processes in real-time and give users information in a more realtime, self-service manner.

### FEW would argue that one of TCP s strengths lies in its

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 13, NO. 8, OCTOBER 1995 1465 TCP Vegas: End to End Congestion Avoidance on a Global Internet Lawrence S. Brakmo, Student Member, IEEE, and Larry L.

### Improving the Performance of HTTP over High Bandwidth-Delay Product circuits

Improving the Performance of HTTP over High Bandwidth-Delay Product circuits A.J. McGregor National Laboratory for Applied Network Research San Diego Super Computer Center 10100 Hopkins Drive, San Diego,

### D1.2 Network Load Balancing

D1. Network Load Balancing Ronald van der Pol, Freek Dijkstra, Igor Idziejczak, and Mark Meijerink SARA Computing and Networking Services, Science Park 11, 9 XG Amsterdam, The Netherlands June ronald.vanderpol@sara.nl,freek.dijkstra@sara.nl,

### Table of Contents INTRODUCTION... 3. Prerequisites... 3 Audience... 3 Report Metrics... 3

Table of Contents INTRODUCTION... 3 Prerequisites... 3 Audience... 3 Report Metrics... 3 IS MY TEST CONFIGURATION (DURATION / ITERATIONS SETTING ) APPROPRIATE?... 4 Request / Response Status Summary...

### 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

### Top 10 Tips for z/os Network Performance Monitoring with OMEGAMON Ernie Gilman

Top 10 Tips for z/os Network Performance Monitoring with OMEGAMON Ernie Gilman IBM Sr Consulting IT Specialist Session 10723 Agenda Overview of OMEGAMON for Mainframe Networks FP3 and z/os 1.12 1.OSA Express

### Improving Online Video Quality and Accelerating Downloads

White Paper Improving Online Video Quality and Accelerating Downloads The FastTCP Network Enhancement Table of Contents Overview 1 The Need For Speed 2 Transmission Control Protocol: Evolution & Limitations

### SSL DOES NOT MEAN SOL What if you don t have the server keys?

SSL DOES NOT MEAN SOL What if you don t have the server keys? J. Scott Haugdahl Architect, Blue Cross Blue Shield MN Robert Bullen Systems Engineer, Blue Cross Blue Shield MN Setting Expectations This

### Layer 4-7 Server Load Balancing. Security, High-Availability and Scalability of Web and Application Servers

Layer 4-7 Server Load Balancing Security, High-Availability and Scalability of Web and Application Servers Foundry Overview Mission: World Headquarters San Jose, California Performance, High Availability,

### Linux TCP Implementation Issues in High-Speed Networks

Linux TCP Implementation Issues in High-Speed Networks D.J.Leith Hamilton Institute, Ireland www.hamilton.ie 1. Implementation Issues 1.1. SACK algorithm inefficient Packets in flight and not yet acknowledged

### Introduction to Network Security Lab 1 - Wireshark

Introduction to Network Security Lab 1 - Wireshark Bridges To Computing 1 Introduction: In our last lecture we discussed the Internet the World Wide Web and the Protocols that are used to facilitate communication

### Nomadic Communications Labs. Alessandro Villani avillani@science.unitn.it

Nomadic Communications Labs Alessandro Villani avillani@science.unitn.it Other Tools for the performances evaluation of a network Tools overview During our test we used IPERF: a very simple tools for the

### Ignoring the Great Firewall of China

An Overview of Ignoring the Great Firewall of China By: Matt Landau Original Paper: Ignoring the Great Firewall of China Richard Clayton, Steven J. Murdoch, and Robert N. M. Watson University of Cambridge,

### Linux 2.4 Implementation of Westwood+ TCP with rate-halving: A Performance Evaluation over the Internet

Linux. Implementation of TCP with rate-halving: A Performance Evaluation over the Internet A. Dell Aera, L. A. Grieco, S. Mascolo Dipartimento di Elettrotecnica ed Elettronica Politecnico di Bari Via Orabona,

### Improving Internet Video Streaming Performance by Parallel TCP-based Request-Response Streams

Improving Internet Video Streaming Performance by Parallel TCP-based Request-Response Streams Robert Kuschnig, Ingo Kofler, Hermann Hellwagner Institute of Information Technology ITEC), Klagenfurt University,

### Tutorial on Network Management and Measurements. Tasos Alexandridis analexan@csd.uoc.gr

Tutorial on Network Management and Measurements Tasos Alexandridis analexan@csd.uoc.gr Network management Simple Network Management Protocol (SNMP) AP s SYSLOG messages Network Measurements and Analysis

### Accelerating File Transfers Increase File Transfer Speeds in Poorly-Performing Networks

Accelerating File Transfers Increase File Transfer Speeds in Poorly-Performing Networks Contents Introduction... 2 Common File Delivery Methods... 2 Understanding FTP... 3 Latency and its effect on FTP...

### Stateful Firewalls. Hank and Foo

Stateful Firewalls Hank and Foo 1 Types of firewalls Packet filter (stateless) Proxy firewalls Stateful inspection Deep packet inspection 2 Packet filter (Access Control Lists) Treats each packet in isolation

### CS 356 Lecture 16 Denial of Service. Spring 2013

CS 356 Lecture 16 Denial of Service Spring 2013 Review Chapter 1: Basic Concepts and Terminology Chapter 2: Basic Cryptographic Tools Chapter 3 User Authentication Chapter 4 Access Control Lists Chapter

### Servicesin ns-3. Outline SIMULACIÓN DE PROTOCOLOS DE ENRUTAMIENTO PARA REDES MÓVILES AD-HOC MEDIANTE HERRRAMIENTA DE SIMULACIÓN NS-3

SIMULACIÓN DE PROTOCOLOS DE ENRUTAMIENTO PARA REDES MÓVILES AD-HOC MEDIANTE HERRRAMIENTA DE SIMULACIÓN NS-3 Servicesin Outline 1. Services in Sockets UDP TCP Bulk Application FTP On off Application 2.

### LAKE REGION ELECTRIC COOPERATIVE, INC. BROADBAND INTERNET SERVICE DISCLOSURES. Updated September, 2013

LAKE REGION ELECTRIC COOPERATIVE, INC. BROADBAND INTERNET SERVICE DISCLOSURES Updated September, 2013 Consistent with FCC regulations, 1 Lake Region Electric Cooperative, Inc. provides this information

### Syslog Performance: Data Modeling and Transport

Syslog Performance: Data Modeling and Transport Mohammad Rajiullah, Reine Lundin, Anna Brunstrom, and Stefan Lindskog Department of Computer Science, Karlstad University SE-65 88 Karlstad, Sweden Email:

### Dateless and DNS Desperate! Stateless. Geoff Huston APNIC

Dateless and DNS Desperate! Stateless Geoff Huston APNIC Can I do both at once? This is definitely a Bad Idea with that intriguing possibility that it just might be made to work making it a Useless Tool

### Technical Series. A Prolexic White Paper. Firewalls: Limitations When Applied to DDoS Protection

A Prolexic White Paper Firewalls: Limitations When Applied to DDoS Protection Introduction Firewalls are often used to restrict certain protocols during normal network situations and when Distributed Denial

### Size-based Scheduling to Improve Web Performance

Size-based Scheduling to Improve Web Performance Mor Harchol-Balter Bianca Schroeder Nikhil Bansal Mukesh Agrawal School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 harchol,bianca,nikhil,mukesh

### Technote. SmartNode Quality of Service for VoIP on the Internet Access Link

Technote SmartNode Quality of Service for VoIP on the Internet Access Link Applies to the following products SmartNode 1000 Series SmartNode 2000 Series SmartNode 4520 Series Overview Initially designed

### 2.2 Methods of Distributed Denial of Service Attacks. 2.1 Methods of Denial of Service Attacks

Distributed Denial of Service Attacks Felix Lau Simon Fraser University Burnaby, BC, Canada V5A 1S6 fwlau@cs.sfu.ca Stuart H. Rubin SPAWAR Systems Center San Diego, CA, USA 92152-5001 srubin@spawar.navy.mil

### CSE331: Introduction to Networks and Security. Lecture 12 Fall 2006

CSE331: Introduction to Networks and Security Lecture 12 Fall 2006 Announcements Midterm I will be held Friday, Oct. 6th. True/False Multiple Choice Calculation Short answer Short essay Project 2 is on

### Firewalls, Tunnels, and Network Intrusion Detection. Firewalls

Firewalls, Tunnels, and Network Intrusion Detection 1 Firewalls A firewall is an integrated collection of security measures designed to prevent unauthorized electronic access to a networked computer system.

### Multiple Choice Questions

Comp18112: VoIP Examples/Revision 1 Barry 7/03/11 University of Manchester School of Computer Science COMP18112: Foundations of Distributed Computing 2011 Voice over Internet Protocol (VoIP) Questions

### Web Applications Engineering: Performance Analysis: Operational Laws

Web Applications Engineering: Performance Analysis: Operational Laws Service Oriented Computing Group, CSE, UNSW Week 11 Material in these Lecture Notes is derived from: Performance by Design: Computer

### Top 10 Tips for z/os Network Performance Monitoring with OMEGAMON Session 11899

Top 10 Tips for z/os Network Performance Monitoring with OMEGAMON Session 11899 Dean Butler butlerde@us.ibm.com 2012 IBM Corporation Agenda IBM Software Group Tivoli software Best Practices in Monitoring

### A Summary of Network Traffic Monitoring and Analysis Techniques

http://www.cse.wustl.edu/~jain/cse567-06/ftp/net_monitoring/index.html 1 of 9 A Summary of Network Traffic Monitoring and Analysis Techniques Alisha Cecil, acecil19@yahoo.com Abstract As company intranets

### Introduction to VoIP. 陳 懷 恩 博 士 助 理 教 授 兼 計 算 機 中 心 資 訊 網 路 組 組 長 國 立 宜 蘭 大 學 資 工 系 Email: wechen@niu.edu.tw TEL: 03-9357400 # 340

Introduction to VoIP 陳 懷 恩 博 士 助 理 教 授 兼 計 算 機 中 心 資 訊 網 路 組 組 長 國 立 宜 蘭 大 學 資 工 系 Email: wechen@niu.edu.tw TEL: 3-93574 # 34 Outline Introduction VoIP Call Tpyes VoIP Equipments Speech and Codecs Transport

### Path-F3: Improving Accuracy and Network Load in Available Bandwidth Estimation based on SLoPS Methodology

2009 International Symposium on Computing, Communication, and Control (ISCCC 2009) Proc.of CSIT vol.1 (2011) (2011) IACSIT Press, Singapore Path-F3: Improving Accuracy and Network Load in Available Estimation

### DSA-1000 / PRT-1000 Device Server / Thermal Printer

LevelOne DSA-1000 / PRT-1000 Device Server / Thermal Printer User Manual V2.0 TABLE OF CONTENTS 1. INTRODUCTION...- 3-2. DEVICE OVERVIEW...- 7-3. HARDWARE SETUP...- 10-4. SYSTEM CONFIGURATION...- 12 -,

### Lecture 5: Network Attacks I. Course Admin

Lecture 5: Network Attacks I CS 336/536: Computer Network Security Fall 2013 Nitesh Saxena Adopted from previous lectures by Keith Ross Course Admin HW/Lab 1 Due Coming Monday 11am Lab sessions are active

### MULTI WAN TECHNICAL OVERVIEW

MULTI WAN TECHNICAL OVERVIEW The Multi WAN feature will allow the service provider to load balanced all client TCP and UDP traffic only. It also provides redundancy for HA. Traffic that is load balanced:

### Defending against a Denial-of-Service Attack on TCP

Defending against a Denial-of-Service Attack on TCP Pars Mutaf pars@likya.iyte.edu.tr Department of Computer Engineering Izmir Institute of Technology Gaziosmanpasa Blv. No. 16 Cankaya Izmir 323 Turkey

### Evaluation and Characterization of Available Bandwidth Probing Techniques

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 21, NO. 6, AUGUST 2003 879 Evaluation and Characterization of Available Bandwidth Probing Techniques Ningning Hu, Student Member, IEEE, and Peter

### What VoIP Requires From a Data Network

A White Paper by NEC Unified Solutions, Inc. What VoIP Requires From a Data Network Introduction Here is a very common story. A customer has a data network based on TCP/IP that is working well. He can

### Application Level Network Performance Monitoring

Application Level Network Performance Monitoring Manuel Stich Master's Thesis August 26, 2011 School of Computer and Communication Sciences Ecole Polytechnique Fédérale de Lausanne Supervisor: Prof. Patrick

### Deployment Guide AX Series with Citrix XenApp 6.5

Deployment Guide AX Series with Citrix XenApp 6.5 DG_XenApp_052012.1 TABLE OF CONTENTS 1 Introduction... 4 1 Deployment Guide Overview... 4 2 Deployment Guide Prerequisites... 4 3 Accessing the AX Series

### A Distributed Defense Mechanism Against Low-Bandwidth TCP SYN Flooding Attacks

A Distributed Defense Mechanism Against Low-Bandwidth TCP SYN Flooding Attacks 1. General presentation of the Connection Request Distribution system 2. The CRD system in depth 3. Carrying out the tests

### Security Technology White Paper

Security Technology White Paper Issue 01 Date 2012-10-30 HUAWEI TECHNOLOGIES CO., LTD. 2012. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without

### Skype over UMTS. Tobias Hoßfeld www3.informatik.uni-wuerzburg.de. University of Würzburg Informatik III (Distributed Systems) Prof. Dr. P.

Inmatik III () Prof. Dr. P. Tran-Gia Skype over UMTS Talk (25+5min) ITG Fachgruppe 5.2.4 VoIP over Wireless 15th May 2006, WürzburgW P2P Applications Across Mobile Networks When Do We Need Rate Control

### Using SYN Flood Protection in SonicOS Enhanced

SonicOS Using SYN Flood Protection in SonicOS Enhanced Introduction This TechNote will describe SYN Flood protection can be activated on SonicWALL security appliance to protect internal networks. It will

### Application Note Telephony Service over Satellite

Voice over Application Note Telephony Service over Satellite January 2012 Data Sells but Voice Pays In the early years of the industry, networks were deployed primarily for telephony services. As time

### Layer 7 Load Balancing and Content Customization

C H A P T E R 4 Layer 7 Load Balancing and Content Customization This chapter will discuss the methods and protocols involved in accomplishing a Layer 7 load-balancing solution. The reasons for and benefits

### 3. MONITORING AND TESTING THE ETHERNET NETWORK

3. MONITORING AND TESTING THE ETHERNET NETWORK 3.1 Introduction The following parameters are covered by the Ethernet performance metrics: Latency (delay) the amount of time required for a frame to travel

### RESOURCE ALLOCATION FOR INTERACTIVE TRAFFIC CLASS OVER GPRS

RESOURCE ALLOCATION FOR INTERACTIVE TRAFFIC CLASS OVER GPRS Edward Nowicki and John Murphy 1 ABSTRACT The General Packet Radio Service (GPRS) is a new bearer service for GSM that greatly simplify wireless

### Single Pass Load Balancing with Session Persistence in IPv6 Network. C. J. (Charlie) Liu Network Operations Charter Communications

Single Pass Load Balancing with Session Persistence in IPv6 Network C. J. (Charlie) Liu Network Operations Charter Communications Load Balancer Today o Load balancing is still in use today. It is now considered

### Secure Network Access System (SNAS) Indigenous Next Generation Network Security Solutions

Secure Network Access System (SNAS) Indigenous Next Generation Network Security Solutions Gigi Joseph, Computer Division,BARC. Gigi@barc.gov.in Intranet Security Components Network Admission Control (NAC)

### JACKSON ENERGY AUTHORITY BROADBAND INTERNET SERVICE DISCLOSURES. Update November 20, 2011

JACKSON ENERGY AUTHORITY BROADBAND INTERNET SERVICE DISCLOSURES Update November 20, 2011 Consistent with FCC regulations, 1 Jackson Energy Authority ( JEA ) provides this information about our broadband

### NAT and Firewall Traversal with STUN / TURN / ICE

NAT and Firewall Traversal with STUN / TURN / ICE Simon Perreault Viagénie {mailto sip}:simon.perreault@viagenie.ca http://www.viagenie.ca Credentials Consultant in IP networking and VoIP at Viagénie.

### TR-143. Enabling Network Throughput Performance Tests and Statistical Monitoring TECHNICAL REPORT. Issue: 1 Corrigendum 1 Issue Date: December 2008

TECHNICAL REPORT TR143 Enabling Network Throughput Performance Tests and Statistical Monitoring Issue: 1 Corrigendum 1 Issue Date: December 2008 The Broadband Forum. All rights reserved. Notice The Broadband

### CS 457 Lecture 19 Global Internet - BGP. Fall 2011

CS 457 Lecture 19 Global Internet - BGP Fall 2011 Decision Process Calculate degree of preference for each route in Adj-RIB-In as follows (apply following steps until one route is left): select route with

### CS 3251: Computer Networking 1 Security Protocols I

Georgia Tech CS 3251: Computer Networking 1 Security Protocols I Brad Reaves, PhD Student 11/21/13 (slides from Prof. Patrick Traynor) CS 3251 - Computer Networks I Last Time Trying to prove who you are

### Content Delivery Networks

Content Delivery Networks Terena 2000 ftp://ftpeng.cisco.com/sgai/t2000cdn.pdf Silvano Gai Cisco Systems, USA Politecnico di Torino, IT sgai@cisco.com Terena 2000 1 Agenda What are Content Delivery Networks?

### Application Firewall Configuration Examples

SonicOS Application Firewall Configuration Examples This technote describes practical usage examples with the SonicOS Application Firewall (AF) feature introduced in SonicOS Enhanced 4.0. The Application

### Advanced Computer Networks. Layer-7-Switching and Loadbalancing

Oriana Riva, Department of Computer Science ETH Zürich Advanced Computer Networks 263-3501-00 Layer-7-Switching and Loadbalancing Patrick Stuedi, Qin Yin and Timothy Roscoe Spring Semester 2015 Outline

### Scheduling for QoS Management

Scheduling for QoS Management Domenico Massimo Parrucci Condello isti information science Facoltà and di Scienze technology e Tecnologie institute 1/number 1 Outline What is Queue Management and Scheduling?

### DeltaV System Health Monitoring Networking and Security

DeltaV Distributed Control System White Paper DeltaV System Health Monitoring Networking and Security Introduction Emerson Process Management s DeltaV System Health Monitoring service enables you to proactively

### Load Balancing and Sessions. C. Kopparapu, Load Balancing Servers, Firewalls and Caches. Wiley, 2002.

Load Balancing and Sessions C. Kopparapu, Load Balancing Servers, Firewalls and Caches. Wiley, 2002. Scalability multiple servers Availability server fails Manageability Goals do not route to it take servers

### INITIAL TOOL FOR MONITORING PERFORMANCE OF WEB SITES

INITIAL TOOL FOR MONITORING PERFORMANCE OF WEB SITES Cristina Hava & Stefan Holban Faculty of Automation and Computer Engineering, Politehnica University Timisoara, 2 Vasile Parvan, Timisoara, Romania,

### Chapter 28 Denial of Service (DoS) Attack Prevention

Chapter 28 Denial of Service (DoS) Attack Prevention Introduction... 28-2 Overview of Denial of Service Attacks... 28-2 IP Options... 28-2 LAND Attack... 28-3 Ping of Death Attack... 28-4 Smurf Attack...

### Denial Of Service. Types of attacks

Denial Of Service The goal of a denial of service attack is to deny legitimate users access to a particular resource. An incident is considered an attack if a malicious user intentionally disrupts service

### TRANSPORT LAYER AND SECURITY PROTOCOLS FOR AD HOC WIRELESS NETWORKS

Chapter 9 TRANSPORT LAYER AND SECURITY PROTOCOLS FOR AD HOC WIRELESS NETWORKS 9.1 INTRODUCTION The objectives of a transport layer protocol include the setting up of an end-to-end connection, end-to-end

### Rate adaptation, Congestion Control and Fairness: A Tutorial. JEAN-YVES LE BOUDEC Ecole Polytechnique Fédérale de Lausanne (EPFL)

Rate adaptation, Congestion Control and Fairness: A Tutorial JEAN-YVES LE BOUDEC Ecole Polytechnique Fédérale de Lausanne (EPFL) September 12, 2014 2 Thanks to all who contributed to reviews and debugging

### Continuous One-Way Available Bandwidth Change Detection in High Definition Video Conferencing

Continuous One-Way Available Bandwidth Change Detection in High Definition Video Conferencing Aziz Khanchi, Mehdi Semsarzadeh, Abbas Javadtalab and Shervin Shirmohammadi Distributed and Collaborative Virtual

### Linux MDS Firewall Supplement

Linux MDS Firewall Supplement Table of Contents Introduction... 1 Two Options for Building a Firewall... 2 Overview of the iptables Command-Line Utility... 2 Overview of the set_fwlevel Command... 2 File

### An End-to-End Approach for Transparent Mobility across Heterogeneous Wireless Networks

Mobile Networks and Applications 9, 363 378, 2004 2004 Kluwer Academic Publishers. Manufactured in The Netherlands. An End-to-End Approach for Transparent Mobility across Heterogeneous Wireless Networks

### Case Study: F5 Load Balancer and TCP Idle Timer / fastl4 Profile

Case Study: F5 Load Balancer and TCP Idle Timer / fastl4 Profile This describes a problem whereby a client connects to a server then waits for a report to complete before retrieving it. The report took

### A Novel Adaptive Distributed Load Balancing Strategy for Cluster *

A Novel Adaptive Distributed Balancing Strategy for Cluster * Hai Jin, Bin Cheng, Shengli Li Cluster and Grid Computing Lab Huazhong University of Science & Technology, Wuhan, China {hjin,showersky}@hust.edu.cn

### Encapsulating Voice in IP Packets

Encapsulating Voice in IP Packets Major VoIP Protocols This topic defines the major VoIP protocols and matches them with the seven layers of the OSI model. Major VoIP Protocols 15 The major VoIP protocols

### Protecting Mobile Devices From TCP Flooding Attacks

Protecting Mobile Devices From TCP Flooding Attacks Yogesh Swami % and Hannes Tschofenig* % Nokia Research Center, Palo Alto, CA, USA. * Siemens Corporate Technology, Munich, DE. 1 Motivation Anatomy of

### IOS Server Load Balancing

IOS Server Load Balancing This feature module describes the Cisco IOS Server Load Balancing (SLB) feature. It includes the following sections: Feature Overview, page 1 Supported Platforms, page 5 Supported

lin Elfiq Link Load Balancer Frequently Asked Questions (FAQ) For Elfiq Operating System (EOS) version 3.1.x Document Revision 1.8 May 2006 Elfiq Solutions www.elfiq.com Page 2 / 14 Table of contents 1

### WHITE PAPER September 2012. CA Nimsoft For Network Monitoring

WHITE PAPER September 2012 CA Nimsoft For Network Monitoring Table of Contents EXECUTIVE SUMMARY 3 Solution overview 3 CA Nimsoft Monitor specialized probes 3 Network and application connectivity probe

### NEXT GENERATION FIREWALL PRODUCT ANALYSIS

NEXT GENERATION FIREWALL PRODUCT ANALYSIS Palo Alto Networks PA- 3020 v6.0.5- h3 Authors Christopher Conrad, Joseph Pearce Overview NSS Labs performed an independent test of the Palo Alto Networks PA-

### DATA COMMUNICATION AND NETWORKS

DATA COMMUNICATION AND NETWORKS 1. Define the term Computer Networks. A Computer network is a number if computers interconnected by one or more transmission paths. The transmission path often is the telephone

### Classic IOS Firewall using CBACs. 2012 Cisco and/or its affiliates. All rights reserved. 1

Classic IOS Firewall using CBACs 2012 Cisco and/or its affiliates. All rights reserved. 1 Although CBAC serves as a good foundation for understanding the revolutionary path toward modern zone based firewalls,

### Computer Networks and the Internet

? Computer the IMT2431 - Data Communication and Network Security January 7, 2008 ? Teachers are Lasse Øverlier and http://www.hig.no/~erikh Lectures and Lab in A126/A115 Course webpage http://www.hig.no/imt/in/emnesider/imt2431

### A Catechistic Method for Traffic Pattern Discovery in MANET

A Catechistic Method for Traffic Pattern Discovery in MANET R. Saranya 1, R. Santhosh 2 1 PG Scholar, Computer Science and Engineering, Karpagam University, Coimbatore. 2 Assistant Professor, Computer