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Surveyor IP Performance Measurements. Matt Zekauskas matt@advanced.org June, 1999 NLANR/I2 Joint Techs. IP Performance Metrics. IETF IPPM effort Framework and Connectivity RFC One-way delay and packet loss drafts Others: round-trip delay, bulk transfer, DV

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surveyor ip performance measurements

Surveyor IP Performance Measurements

Matt Zekauskas

matt@advanced.org

June, 1999

NLANR/I2 Joint Techs

ip performance metrics
IP Performance Metrics
  • IETF IPPM effort
    • Framework and Connectivity RFC
    • One-way delay and packet loss drafts
    • Others: round-trip delay, bulk transfer, DV
  • Surveyor: implementation of one-way delay and packet loss metrics
motivation for measuring delay
Motivation for measuring delay
  • Minimum of delay: transmission/propagation delay
  • Variation of delay: queuing delay
  • Large delay makes sustaining high-bandwidth flows harder
  • Erratic variation in delay makes real-time apps harder
slide4
Uses
  • Problem determination
  • Engineering (trends, loads)
  • Monitor QoS
  • Feedback to advanced applications(for example, Tele-Immersion)
the surveyor infrastructure
The Surveyor Infrastructure
  • Measurement machines at campuses and at other interesting places along paths (e.g., gigaPoPs, interconnects)
  • GPS to synchronize clocks
  • Centralized database to store measurement data
  • Web based reporting and analysis tools
measurement machines
Dell 400 MHz Pentium Pro

128 MBytes RAM; 8 GBytes disk

BSDI Unix

TrueTime GPS card and antenna (coax)

Network Interface (10/100bT, FDDI, OC3 ATM in alpha)

Special driver for the GPS card

Measurement Machines
measurement technology
Measurement Technology
  • Active tests of one-way delay and loss
    • Measurement daemon
    • Test packets time-stamped with GPS time
    • Back-to-back calibration: 95% of measurements ± 100 s  10 s soon
    • Measurements centrally managed
  • Concurrent routing measurements
ongoing tests routing
Ongoing Tests - Routing
  • Traceroute to same sites as One-Way delay
  • Scheduled with Poisson process
    • average rate: one every 10 minutes
central database machine
Collects performance data from the measurement machines [ssh, pull]

Stores the data in a home-grown database

So far, all measurements taken on-line

Serves data and summaries to reporting and analysis tools [http]

Central Database Machine
current surveyor deployment
50 machines

Universities

Tele-Immersion Labs

National Labs

…others

1883 paths

NASA Ames XP

I2 gigaPoPs (some)

CA*net2 gigaPoPs

APAN sites

Abilene router nodes up with NTP, awaiting GPS

Current Surveyor Deployment
reporting and analysis tools
Reporting and analysis tools
  • Web based tools
  • Daily summary reports
  • Integration with route measurements
  • Java applet to dynamically graph almost ready
  • Developing asynchronous notification of anomalies
daily summary reports
Daily summary reports

Take a 24-hour sample for a given path

Divide it into one-minute sub-samples

For each one-minute sub-sample:

Minimum delay (blue)

50th percentile (green)

90th percentile (red)

lessons so far
Lessons so far
  • Routing is asymmetric
  • Even when routing is symmetric,queuing is asymmetric
  • Can detect level 2 changes (SONET failover or ATM)
  • HPC connections do fall back to commodity paths, sometimes frequently or for long periods
summary
Summary
  • One-way Delay and Loss are
    • practical
    • useful
  • Surveyor infrastructure growing
  • Dynamic plotting, asynchronous notification coming soon
  • Now focus on analysis and applications
more info
More info
  • Surveyor project info
    • http://www.advanced.org/surveyor/
  • Access to plots
    • http://ippm-db.advanced.org/plots/
  • IETF IPPM WG
    • http://www.advanced.org/IPPM/
  • My email: matt@advanced.org