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Packet Loss NLM<=>HEAnet

Packet Loss NLM<=>HEAnet. Internet2 High-performance Applications Support October 31 st , 2000 Atlanta, Georgia. Michael Gill National Library of Medicine (NLM) Bethesda, Maryland USA Victor Reijs HEAnet, Dublin Ireland. Preparation for interactive multimedia demonstration.

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Packet Loss NLM<=>HEAnet

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  1. Packet Loss NLM<=>HEAnet Internet2 High-performance Applications Support October 31st, 2000 Atlanta, Georgia Michael GillNational Library of Medicine (NLM)Bethesda, Maryland USAVictor ReijsHEAnet, Dublin Ireland

  2. Preparation for interactive multimedia demonstration • Learning Collaboratory (at NLM) <=> Centre for Healthcare Informatics (at Trinity College Dublin) • http://www.cs.tcd.ie/chi/tcdnlm/ • Using MPEG-2 Codecs at each end • Camvision-2, from Litton Network Access Systems • 1.5 => 15 Mbit/s, low-latency video • Litton supplied demo unit for each end • Loan from TERENA • NLM later purchased three units

  3. Initial testing • Early results (March) showed consistent packet loss • Tools were limited: • PingPlotter (www.pingplotter.com) • cv2sim.exe (simulates video loading without hardware codec, supplied by Litton) • More than 1% loss destroys acceptable MPEG-2 video transmission • Time Zone difference • USA=>Dublin=+5 hours

  4. Routing/Peerings • Asymmetrical routing • NLM -> vBNS+ -> Abilene -> DANTE -> HEAnet • First using vBNS+ (over West of America): long delays • NLM -> Abilene -> DANTE -> HEAnet • 90 - 100 msec • Rerouting due to upgrading links from OC-3c to OC-12c

  5. Equipment/cable/configuration issues • Different connectors then ordered cables • Both sides need to be PAL or NTSC • Exploring Huge buffer settings for all routers in path • Ethernet cable rotten • Mismatching ATM PVC configuration • OC-12c fiber had to replaced • Rotten OC-12c ATM interface

  6. Bandwidth • 34 Mbit/s transatlantic at IP level (T3) • USA=>HEAnet heavy traffic • Overbooked ATM link • QoS: Committed Access Rate (CAR) • HEAnet=>USA lighter traffic • Testing during holidays/low-usage hours • Upgrading • Teleglobe (OC-3c -> OC-12c) • Abilene (shared OC-3c -> OC-12c) • HEAnet (T3 -> OC-3c: 2Q 2001)

  7. Present conclusions • Chain of networks • multi kingdom problem • Check all router interfaces in the whole path • Operational network management is not run to have very low (<1%) packet drop

  8. Changed test scenario • QoS grid • Service Level Mangers • Service Access Points • IPPM measurements • E.g. Surveyor, RIPE Test Traffic project (both using GPS) • Proprietary solutions: Chariot/Qcheck by NetIQ • Install test points in the path • At server, client and peering locations • Provide these test points as part of network service

  9. All in a row • We had all kind of problems • Formal demonstrations postponed twice • March 2000: Testing with tools (packet loss) • May 2000: First video pictures (unacceptable quality) • July 2000: Good quality video for a few days!!! • Oct 2000: Unacceptable quality and still testing • NLM => HEAnet still unacceptable quality • HEAnet => NLM fairly good on short tests • Abilene Premium service and HEAnet bandwidth upgrade • QoS grid needed

  10. Questions? Michael Gill, mike_gill@nlm.nih.gov Victor Reijs. victor.reijs@heanet.ie

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