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Advanced Network Diagnostic Tools

Learn how advanced network diagnostic tools can identify and resolve problems with host configurations, local infrastructure, and applications. Discover the latest initiatives in performance monitoring and get access to a range of user-friendly tools. Ensure your network meets your expectations.

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Advanced Network Diagnostic Tools

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  1. Advanced Network Diagnostic Tools Richard Carlson EVN-NREN workshop

  2. End-User viewpoint • When problems exist, it’s the networks fault! • Advanced tools can • Point out problems with the host config • Point out problems with the local infrastructure • Point out problems with the application • Aid network operators in verifying when problems have been resolved

  3. Basic Premise • Application’s performance should meet your expectations! • (A minimum of 10 MBps between any 2 hosts/sites connected to REN based networks) • If they don’t you should complain!

  4. Simple Network Picture Bob’s Host Network Infrastructure Carol’s Host

  5. Switch 2 Switch 3 R5 R4 R8 R1 R3 R6 Switch 1 R9 R2 R7 Switch 4 Network Infrastructure

  6. PerfSonar – Next Steps in Performance Monitoring • New Initiative involving multiple partners • ESnet (DOE labs) • GEANT (European Research and Education network) • Internet2 (Abilene and connectors) • Brazil

  7. perfSONAR • Set of advanced services • Active Measurement tools and storage • Topology and Lookup to find devices • Provide L1, L2, and L3 views • Common user interface (perfSONAR UI)

  8. perfSONAR Measurement Points • Existing Measurement Points • SNMP based router views • BWCTL • OWAMP/Hades • Data presented helps network operators more than end-users

  9. Advanced user tools • Existing NDT tool • Allows users to test network path for a limited number of common problems • Existing NPAD tool • Allows users to test local network infrastructure while simulating a long path • NPToolKit Live-CD Knoppix disk • Bootable CD that contains all the tools described in this talk http://e2epi.internet2.edu/network-performance-toolkit.html

  10. Network Diagnostic Tool (NDT) • Measure performance to users desktop • Identify real problems for real users • Network infrastructure is the problem • Host tuning issues are the problem • Make tool simple to use and understand • Make tool useful for users and network administrators

  11. NDT sample Results

  12. perfSONAR NDT • Integrating NDT/NPAD into the perfSONAR • Add LS registration message • Ability to automatically pass results to NOC • Add to L3 Topology service • Authentication • perfSONAR UI plug-in

  13. NPAD/pathdiag • A new tool from researchers at Pittsburgh Supercomputer Center • Finds problems that affect long network paths • Uses Web100-enhanced Linux based server • Web based Java client

  14. Long Path Problem • E2E application performance is dependant on distance between hosts • Full size frame time at 100 Mbps • Frame = 1500 Bytes • Time = 0.12 msec • In flight for 1 msec RTT = 8 packets • In flight for 70 msec RTT = 583 packets

  15. Switch 2 Switch 3 R5 R4 R8 R1 R3 R6 Switch 1 R9 R2 R7 Switch 4 Long Path Problem H2 70 msec H1 – H3 1 msec H1 – H2 X H3 H1

  16. TCP Congestion Avoidance • Cut number of packets by ½ • Increase by 1 per RTT • LAN (RTT=1msec) • In flight changes to 4 packets • Time to increase back to 8 is 4msec • WAN (RTT = 70 msec) • In flight changes to 292 packets • Time to increase back to 583 is 20.4 seconds

  17. NPAD Server main page

  18. NPAD Sample results

  19. Network Admin Tools • BWCTL – Bandwidth Control • Allows single person operation over wide area testing environment • Runs NLANR ‘iperf’ program • OWAMP – One way Delay Measurement • Advanced ‘ping’ command • Allows single person operation over wide area testing environment

  20. Google it! • Enter “tuning tcp” into the google search engine. • Top 2 hits are: http://www.psc.edu/networking/perf_tune.html http://www-didc.lbl.gov/TCP-tuning/TCP-tuning.html

  21. PSC Tuning Page

  22. LBNL Tuning Page

  23. Dedicated Circuit Services • Multi-Domain initiative (DICE – Dante, Internet2, Canarie, ESnet) • Bandwidth in OC-1 steps (51 Mbps – 10 Gbps • Allows automatic setup of dedicated circuits (Lightpaths) • Multiple usage models • Short term (hours to days) – No additional fee • Long Term (days to years) – additional fee

  24. Conclusions • Primary tools useful • Advanced tools are being developed • Developing tools will make things even easier • Demand 10 MB/s as the minimum acceptable throughput rate

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