Commit 32f29761 authored by Leigh B. Stoller's avatar Leigh B. Stoller

More verbiage, more cleanup.

parent 1e175c66
...@@ -37,24 +37,31 @@ ...@@ -37,24 +37,31 @@
To run linktest, select a Linktest test level from the dropdown on the To run linktest, select a Linktest test level from the dropdown on the
<a href="beginexp_html.php3">Begin an Experiment</a> page. <a href="beginexp_html.php3">Begin an Experiment</a> page.
<ul> <ul>
<li>For fastest response, select <a href="#Level1">Level 1 - Connectivity and Latency</a>. This <li> <a href="#Level1"><b>Level 1</b> - Connectivity and Latency</a>:
will check that all nodes respond to ping and that latency is correct. For fastest response, level 1. This will check that all nodes respond
<li>For a more thorough but relatively fast test, select <a to ping and that latency is correct.
href="#Level3">Level 3 - Loss</a>. Test levels are cumulative, so this option includes <br>
Connectivity, Latency, Static Routing (if applicable) and Loss. <li> <a href="#Level3"><b>Level 3</b> - Link Loss</a>: Check link loss
<li>If bandwidth is important in your experiment, select <a characteristics. Test levels are cumulative, so this option also
href="#Level4">Level 4 - Bandwidth</a>. Be warned that the bandwidth includes connectivity, latency, and static routing (if
test takes up to 40 seconds per link. <b>Also note that not all applicable).
bandwidths can be accurately measured</b>. If this happens, a warning will <br>
be placed in the log file for each link that is out of range for <li> <a href="#Level4"><b>Level 4</b> - Bandwidth</a>: If bandwidth is
bandwidth testing. It is up to you to ensure that links are behaving important in your experiment, select level 4. Be warned that the
as you expect them too! bandwidth test takes up to 40 seconds per link. <b>Also note that
not all bandwidths can be accurately measured</b>. If this
happens, a warning will be placed in the log file for each link
that is out of range for bandwidth testing.
</ul> </ul>
<p>If you select a test lest level other than 0, Linktest <p>
will run after the experiment completes its swapin. If a problem is If you select a test lest level other than zero, Linktest will run after
found, testbed-ops is automatically notified and a message will appear the experiment completes its swapin. If a problem is found,
in the activation log. Otherwise, no notification will appear. testbed-ops is automatically notified and a message will appear in the
activation log. Otherwise, no notification will appear. A failure in
linktest will <em><b>not</b> cause the swapin to fail!</em> If traffic
shaping parameters are of critical importance to your experiments,
make sure you take a closer look if linktest reports failures!
</p> </p>
<hr> <hr>
...@@ -72,13 +79,19 @@ in the activation log. Otherwise, no notification will appear. ...@@ -72,13 +79,19 @@ in the activation log. Otherwise, no notification will appear.
<li> As with any automated testing procedure, we have to balance the desire <li> As with any automated testing procedure, we have to balance the desire
for accuracy with the possibility of false positives. To reduce for accuracy with the possibility of false positives. To reduce
the number of false positives, we allow for a small amount of the number of false positives, we allow for a small amount of
fudge of any link. <b>If your results are dependent on total fudge on any link. <b>If your results are dependent on total
accuracy, then you should test your links yourself!</b> accuracy, then you should test your links yourself!</b>
<li> When using linkdelays (endnodeshaping) latency is less accurate <li> When using linkdelays (endnodeshaping) latency is less accurate
because of the 1ms clock resolution that the kernel runs at. At because of the 1ms clock resolution that the kernel runs at. At
worst, latency can be off by up to 2ms, say for a roundtrip ping worst, latency can be off by up to 2ms, say for a roundtrip ping
packet. packet.
<li> Linktest can take a <b>long time</b> on large experiments. Even
on very small experiments (5-10 nodes), doing the full bandwidth test
can 3-4 minutes. You should probably <em>not<em> do bandwidth
tests at swapin on any experiment over 20 nodes unless you are
prepared to wait a <em>long</em> time for the experiment to swap in.
</ul> </ul>
</center> </center>
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