Masaki Hirabaru Tsukuba WAN Symposium 2005 March 8, 2005 e-VLBI and End-to-End Performance over Global Research Internet
Radio Telescopes NICT Kashima Space Center 34m Onsala Space Observatory 20m (left) Perks 64m (right) Australia Telescope National Facility MIT Haystack 18m Shanghai 25m
VLBI (Very Long Baseline Interferometry) delay radio signal from a star correlator A/D clock A/D Internet clock e-VLBI geographically distributed observation, interconnecting radio antennas over the world Large Bandwidth-Delay Product Network issue ASTRONOMY GEODESY ~Gbps Gigabit / real-time VLBI multi-gigabit rate sampling A B A B d
Analyzing Advanced TCP Dynamic Behavior in a Real Network ( Example: From Tokyo to Indianapolis at 1G bps with HighSpeed TCP ) The data was obtained during e-VLBI demonstration at Internet2 Member Meeting in October Throughput RTT Window Sizes Packet Losses
Long-Distance Rover Control minutes round trip delay Image Command Earth Mars
Long-Distance End-to-End Congestion Control Merge (Bottleneck) Overflow Sender (JP) Receiver (US) Feedback 64Kbps x 200ms = 1600B ~ 1 Packet 1Gbps x 200ms = 25MB ~ 16,700 Packets 200ms round trip delay
Advanced TCPs Loss-Based Reno, Scalable, High-Speed, BIC, RED, … Delay-Based Vegas, FAST Explicit Router Notification ECN, XCP, Quick Start, OQ Burstiness on Sender during Slow-Start Time Allowance to Feedback
RouterSwitch 1Gbps 100Mbps b) Device Queuing Delay (µs) Capacity (Mbps) Estimated Queue Size (1500B) Switch A *50 Switch B *180 Switch C *169 Switch D Switch E Router F Router G * set to 100M for measurement Measuring Bottleneck Queue Sizes Switch/Router Queue Size Measurement Result Typical Bottleneck Cases ReceiverSender Capacit y C packet train lost packet measured packet Queue Size = C x (Delay max – Delay min ) RouterSwitch a) Queue ~100 Queue ~1000 VLANs
Kwangju Busan 2.5G Fukuoka Korea 2.5G SONET KOREN Taegu Daejon 10G 1G (10G) 1G Seoul XP Genkai XP Kitakyushu Kashima 1G (10G) Fukuoka Japan 250km 1,000km 2.5G JGN II 9,000km 4,000km Los Angeles Chicago Washington DC MIT Haystack 10G 2.4G APII/JGN II Abilene Koganei 1G(10G) Indianapolis 100km bwctl server Performance Measurement Platform for High-Performance Scientific Data Transfer 10G Tokyo XP / JGN II I-NOC *Performance Measurement Point Directory perf server e-vlbi server JGNII 10G GEANT SWITCH 7,000km TransPAC Pittsburgh U of Tokyo International collaboration to support for science applications U. Hawaii
Summary Network Research Issues in Applications Large Bandwidth-Delay Product Networks Multiple Data Sources / Data Synchronizing Loss Tolerance (5% Loss Allowance) Data Distributions (Multicasting) Operations / Engineering Developments Observatory (Measurement Data Collection) Performance Test Points Global NOCs Collaborations