performance measurements in internet2 guy almes geneve – 15 march 2004
TRANSCRIPT
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Outline
Infrastructure Observations
Software Observations
The Measurements
Putting it all together
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Infrastructure Observations
From 1983 to the present, we have partial meshes and growth in b/s rates:
• 1983: 50 kb/s ARPAnet• 1988: 1.5 Mb/s NSFnet• 1992: 45 Mb/s NSFnet• 1995: 155 Mb/s vBNS => 622 Mb/s• 1998: 2.4 Gb/s Abilene => 9.6 Gb/s
But this rapid growth is now stopping• either stopping at 10 Gb/s or perhaps merely slowed growth
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Abilene Backbone Network
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The partial-mesh with growing b/s rates approach is now ending
Several new approaches are promising:• fuller mesh (=> fewer hops)• dynamic mesh
–adaptive based on measurements–scheduled by users or on-demand
• larger MTUs• focus on effective file transfer
These will be interesting times
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Implications of these new styles• Exciting ideas to be created, tested, deployed• Uncertainty with regard to future end-states• Turmoil during transition from present to future
Increasing holistic attitude to networking• from 'my part works'• to 'ensure system works end to end'
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Software Observations
Evolution of TCP control algorithms• 1986-1992: dramatic improvement
–basis for effective use of wide-area 1.5 Mb/s networks
• 1992-2002: relative neglect–while wide-area networks grew to 2.5 Gb/s
• since about 2003: renewed research vigor–FAST–HS-TCP–Other very good work at Cambridge, Hamilton, North
Carolina State, Rice, Univ Illinois Chicago
Uncertainty
Turmoil
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The Measurements
Items to be measured• TCP throughput• one-way delay (and round-trip)• variation in delay• packet loss• increasingly relevant
Active and passive
Relationship to security trends
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Separate applications of compatible measurements
• within core of a given network (within core)• aggregated sets of networks (extended core?)• between file servers of a given grid (edge to edge)• from grid site to core (edge to core)
Technical accuracy of great importance
Reporting: focusing on near-worst-case• think about performance that is almost always delivered• supports taking a quality control attitude at several layers
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Putting it all Together
User communities are learning to quantify their requirements
Networks then accept the challenge (or not)
Network groups measure their networks
User groups measure delivered performance
Mutual accountability and support
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