Masterclock GPSPCI Spezifikationen

A Network Measurement System for Wide Area NetworksMatei Ciobotaru, C˘at˘alin Meiro¸su, Miron Brezuleanu, Mihai IvanoviciJanuary 15, 2003

CHAPTER 2. NETWORK PERFORMANCE MEASUREMENTS SYSTEMS 9• Some of them can be plugged directly into a computer (Meinberg PCI card)Instead of a GPS receiv

CHAPTER 2. NETWORK PERFORMANCE MEASUREMENTS SYSTEMS 10The computers involved in the system run a Linux with the nanokernel patches. Thisallows a nanos

Chapter 3System Architecture3.1 General overviewThe network tester that we use can generate Gigabit Ethernet traffic and can measure allthe important pe

CHAPTER 3. SYSTEM ARCHITECTURE 12The network cards have internal clocks which are synchronized with the global clock cards.These clock cards are inter

CHAPTER 3. SYSTEM ARCHITECTURE 13This measurement system is currently used (with up to 32 Gigabit Ethernet ports) tocharacterize switches and LANs for

CHAPTER 3. SYSTEM ARCHITECTURE 143.3 Generating IP packetsWe have modified the firmware on the network cards in order to be able to generate IPpackets i

CHAPTER 3. SYSTEM ARCHITECTURE 15previous system. Each computer hosting traffic generator NICs requires a slave clock card.Typically te ns of traffic gene

Chapter 4The GPS-based ClockSynchronization SystemTo overcome the issues related to the synchronization of geographically separated nodeswe decided to

CHAPTER 4. THE GPS-BASED CLOCK SYNCHRONIZATION SYSTEM 174.2 Description of the methodAt each site of the testbed we use one GPS card and several clock

CHAPTER 4. THE GPS-BASED CLOCK SYNCHRONIZATION SYSTEM 18When the clock cards receive this signal, they start waiting for the next pulse on the 1HzPPS

Contents1 Introduction 32 Network Performance Measurements Systems 42.1 Network testers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 4. THE GPS-BASED CLOCK SYNCHRONIZATION SYSTEM 19Local Site #3Local Site #2Local Site #1InternetFigure 4.3: Global synchronization over the Int

Chapter 5Traffic GenerationThe network tester generates traffic according to a traffic description table that is loadedinto the network cards before a test

CHAPTER 5. TRAFFIC GENERATION 21Programmable Network CardsHardware91 1 8 5.000 0 23 1 10 82 30898 1 23 5.000 0 1 2 5 45 100101 1 0 5

CHAPTER 5. TRAFFIC GENERATION 22Distribution Descriptionrand normal( mean, stddev ) The Normal Gaussian distributionwith given mean and variancerand n

CHAPTER 5. TRAFFIC GENERATION 23(a) Packet size (b) VLAN IdFigure 5.2: Sample histograms for the generated trafficThe histograms that result for two of

Chapter 6Measurements and ResultsThe tester was put into operation in the CERN network and some measurements wereperformed at the IP level ([7]). The

CHAPTER 6. MEASUREMENTS AND RESULTS 251085 1090 1095 1100 1105024681012141618x 10−3Latency [us]Latency histogramFigure 6.2: Histogram of latencies for

Chapter 7Conclusions and Future WorkThe network tester was extended to an Internet environment. This implies IP traffic gen-eration and global clock syn

Bibliography[1] Testing and Modeling Ethernet Switches and Networks for use in ATLAS High-LevelTriggersDobinson, R W; Haas, S; Korcyl K; Le Vine, M J;

Appendix AInstallationThe installation consists in placing the GPS and clock boards in the computers, connectingthe cables and the GPS antenna and ins

CONTENTS 25 Traffic Generation 205.1 Traffic profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 Measurements and Results 24

APPENDIX A. INSTALLATION 29• switch 10 - ON (10MHz clock on pin 4)• switch 4 - ON (1Hz pulse on pin 8)• all other - OFFAlso some clock cards have to b

APPENDIX A. INSTALLATION 30A.4.1 The GPS card driverThe GPS kernel module is provided by Meinberg – we are using MBGtools for Linuxv0.2.3beta. On the

APPENDIX A. INSTALLATION 31clock test/clock test 1 3 which sends the command ”3” (READ TIME) to boardnumber 1 (the first board /dev/hslclock0 ). Then y

APPENDIX A. INSTALLATION 32A.4.4 Using the hs masterThis program is used to drive the synchronization mechanism on all computers. After asuccessful in

Appendix BImplementation detailsIn this section we give the basic information on how the synchronization method is imple-mented.The synchronization se

APPENDIX B. IMPLEMENTATION DETAILS 34For this project we use to types of clock cards: master cards and slave cards. The onlydifference between them is

APPENDIX B. IMPLEMENTATION DETAILS 35B.1.2 Software and FirmwareThe firmware is the program that is implemented by the FPGA and that controls allthe ac

APPENDIX B. IMPLEMENTATION DETAILS 36B.3 Manager softwareThe driver software consists of 3 small programs that work together:hs master This is the man

Appendix CResults obtained duringdevelopmentA lot of testing was performed to verify the method (see [4]). The first tests were intended tocheck the GP

APPENDIX C. RESULTS OBTAINED DURING DEVELOPMENT 38Figure C.1: GPS Positional parameters for a period of 5 daysthe difference between the values samples

Chapter 1IntroductionIn this report we present a system for measuring the performance of wide area computernetworks. The system is used to test networ

APPENDIX C. RESULTS OBTAINED DURING DEVELOPMENT 39clocks lose their synchronization [4]) so the preferred method is the one that corrects theclocks at

Appendix DGPS Synchronization HOW-TO1. Install the cards and connect the cables2. Load the kernel modules: for GPS mbgclock.o and clock card hslclock.

APPENDIX D. GPS SYNCHRONIZATION HOW-TO 419. Configure the file hs nodes.conf at each of the sites. In this file you list ONLY thecomputers from that site

Appendix ETroubleshooting synchronizationproblemsProblems with the cables• If the clock is not counting - probably the 10MHz signal from the GPS is no

APPENDIX E. TROUBLESHOOTING SYNCHRONIZATION PROBLEMS 43The GPS cards• Time is not synchronized – check the antenna and the cable. The card shouldsee m

Chapter 2Network PerformanceMeasurements SystemsNetwork testers are devices that can perform measurements of various network parameters.Usually they a

CHAPTER 2. NETWORK PERFORMANCE MEASUREMENTS SYSTEMS 5Figure 2.1: The IXIA IxCore Network Testersystem, BrixWorx. The Brix 2500 Verifier calculates fund

CHAPTER 2. NETWORK PERFORMANCE MEASUREMENTS SYSTEMS 6accuracy of the measurements is good (around 10us) but depends on the operating system.The traffic

CHAPTER 2. NETWORK PERFORMANCE MEASUREMENTS SYSTEMS 7hierarchical configuration where c locks are synchronized to each other and to world-widetime stan

CHAPTER 2. NETWORK PERFORMANCE MEASUREMENTS SYSTEMS 8• Accuracy of 10ms on the client side• Require external time reference (GPS receiver, dial-up, CD