piPEs Tools in Action

1
piPEs Toolsin Action

• Rich Carlson
• rcarlson_at_internet2.edu
• SMM Tools Tutorial
• May 3, 2005

2
Outline

• Brief Introduction to tools
• Using NDT
• Using BWCTL
• Using OWAMP
• Conclusions

3
Overview

• Multiple tools provide
• Different perspectives into the problem
• Insight into the E2E path
• What can these tools tell you
• How hosts are (mis)tuned
• How individual links are operating
• What cant these tools tell you
• Exactly what parameters to change to fix the
  problem

4
piPEs Integration
5
Using NDT

• Scenario 1 User is complaining that network is
  slow.
• Suggestion 1 run NDT test to local server
• Suggestion 2 run NDT test to remote server

6
Using BWCTL

• Scenario 2 User complains that network is slow,
  FTP downloads taking too long.
• Suggestion 1 Use BWCTL to decompose E2E path

7
Using BWCTL remotely

• Scenario 3 User is at remote campus and
  complaining about slow network
• Suggestion 1 run 3rd party BWCTL test

8
Using OWAMP

• Scenario 4 User complains that network is slow
• Suggestion 1 Look for indications of network
  queuing, indicates congestion

9
Caveat's

• Are you testing the network or the server?
• Diagnostic and testing servers may have
  tuning/performance problems too
• Lots of tuning guides on-line (PSC, LBNL, EU, )
• Are you using auto or manual tuning?
• Some OSs may autotune, are these settings
  correct
• User may disable autotuning
• Do you have permission to run tests?
• BWCTL requires pre-configuration of
  Authentication keys

10
Conclusions

• Every problem seems to be a slow network
• TCP hides lower layer problems
• Each tool can help solve a part of the problem
• NDT can identify configuration problems and can
  provide some tuning assistance
• BWCTL can find poor performing links
• OWAMP can identify when links are becoming
  congested