Advanced Network Diagnostic Tools Richard Carlson EVN-NREN workshop End-User viewpoint • When problems exist, it’s the networks fault! • Advanced tools can • Point out problems.
Download ReportTranscript Advanced Network Diagnostic Tools Richard Carlson EVN-NREN workshop End-User viewpoint • When problems exist, it’s the networks fault! • Advanced tools can • Point out problems.
Advanced Network Diagnostic Tools Richard Carlson EVN-NREN workshop 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 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! Simple Network Picture Bob’s Host Network Infrastructure Carol’s Host Network Infrastructure Switch 2 Switch 1 R4 Switch 3 R5 R8 R1 R3 R6 R2 R7 Switch 4 R9 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 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) perfSONAR Measurement Points • Existing Measurement Points • SNMP based router views • BWCTL • OWAMP/Hades • Data presented helps network operators more than end-users 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 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 NDT sample Results 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 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 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 Long Path Problem 1 msec H1 – H2 70 msec H1 – H3 H2 Switch 2 Switch 1 R4 H1 X Switch 3 R5 R8 R1 R3 R6 R2 R7 Switch 4 R9 H3 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 NPAD Server main page NPAD Sample results 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 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 PSC Tuning Page LBNL Tuning Page 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 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