The Computing and Instrumentation Solutions (CIS) Division has
developed a Network Diagnostic Tool (NDT) to help diagnose network
performance and configuration problems. This tool can determine the
speed (Dial-up to OC-192) and duplex (full or half) settings of your
slowest link on the end-to-end path between a desktop client computer
and a server running the NDT. It can determine if your performance
is being limited by network congestion (e.g., competing traffic over
the shared portions of the end-to-end path). It can also determine
if the throughput is limited by the client's network configuration
parameters. Finally, the tool looks for, and reports, two serious
error conditions, duplex mismatch and faulty hardware.
The NDT distribution (web100-tools.tar) contains the programs and
instructions needed to deploy an NDT server on your network or home
institution.
Publicly accessible NDT servers are located at various points on
the global Internet. The main HTML page contains links to these
public servers. Please contact Rich Carlson racarlson@anl.gov to
modify this list. There servers are provided as a service to the
Internet community and this list may change as new servers are
installed and old servers are decommissioned.
Argonne National Laboratory - Chicago IL (USA)
Swiss Education and Research Network (Switzerland)
University of Michigan - Flint MI (USA)
University of California - Santa Cruz (USA)
As noted above the tool will analyze the entire end-to-end path
between the desktop client computer and the NDT server. The results
are organized into three levels, allowing you to drill down to the
level that you or your system administrator needs to identify the
configuration problems. In addition, an email button is provided to
make it easy to report problems to the local administrator. The
user may also manually cut and pasting the results into an email
if the automatic method fails. The ANL NDT may contain new functions
or features under development.
Levels of Results Reported
Level 1 - Main Page
The main page reports the high level results of each test. These
results include the measured throughput to and from your desktop
client computer, a summary of the kind of link you have (Dial-up
to OC-192), if other traffic is using a shared network link(s),
or if serious problems exist. This one sentence overview is intended
to provide the user with a concise picture of the state of the
network (i.e., something is seriously wrong or everything is
working properly).
Level 2 - Statistics
By clicking the "Statistics" button you will learn what is limiting
the throughput and what, if anything, can be done to improve
performance. The summary information on the Main Page is expanded
here to show the results of the five configuration tests. This is
followed by an analysis of what is limiting the throughput of this
test. Throughput may be limited due to your desktop computer's
configuration, the NDT server's configuration, or the network path
connecting these two computers. The percentage of time spent in
each state (i.e., receiver limited, sender limited, or network
limited) is given. Suggestions for improving throughput may also
be given. Lastly, the results of the several TCP performance
enhancement options are reported. The NDT reports the results
enhancement negotiation between the client and server (i.e., what
enhancements are being used), unlike other tools which report what
enhancements could be used.
Level 3 - More Details
By clicking the "More Details" button you will see the detailed
parameters and values that were used to perform this analysis.
Near the bottom of this page you will find the detailed conditional
tests that were used to analyze the five configuration tests. You
will also find the theoretical network limits for this connection.
These limits can help identify the major throughput limiting factors.
Email Results
By clicking the "Report Trouble" button you will automatically
generate an email message that can be sent to your network and/or
system administrator. The NDT administrator can configure the proper
email addresses for your site. This simplifies the steps a user
needs to take to report a problem and ensures that the administrator
received sufficient information to aid in troubleshooting the
reported problem.
For more information and details on bringing up your own server
contact Rich Carlson
Email: RCarlson@internet2.edu
Phone: (734) 352-7043