NAME

SYNOPSIS

DESCRIPTION

OWAMP supports three reporting formats. A textual summary that was designed to be as similar to the results that ping produces as possible. A machine readable summary format (-M). And finally a raw format that prints out the data from each and every packet in as compact of a format as possible (-R). The textual summary also allows the information from each packet to be reported using the -v option. The default textual summary will be used if neither the -M or the -R options are specified. It includes:

SID

Session Identifier. This value is unique for every test session.

Sent, Lost, Duplicates

Number of packets that were sent, lost, and duplicated as seen by OWAMP.

Min Delay, Median Delay, Max Delay, Error Estimate

Minimum, median and maximum delay seen for sample. Maximum error estimate for the sample. (The median is determined using a histogram, so the resolution of this value is bounded by the -b parameter. This can lead to misleading results, for example, for very small values of latency it is possible to see a value for the median that is greater than the maximum, but this is simply due to the resolution of the median measurement.)

Jitter

An estimate of how "stable" the delay samples are. OWAMP reports the the 95th percentile of delay - 50th percentile of delay.

Additional percentiles

If the -a option is used, those additional percentiles from the sample are displayed.

TTL (hops) information

As a packet traverses the network, the IP TTL field is decremented each time the packet crosses a router. OWAMP has been designed to collect the TTL information from the packets. The OWAMP sender sets the TTL of all outgoing packets to 255. The OWAMP receiver retrieves the TTL from the packet. The normal textual report uses this information to report the number of hops (number of routers) the packet traversed. The number of distinct values is reported as well as the minimum and maximum number of hops seen in the given session. The other reporting formats just report raw TTL values as seen in the packets. (It should be noted that if the number of hops reported seems unusually large, it probably means the OWAMP sender was not able to set the TTL value correctly. The traceroute(1) program can be used to verify what OWAMP is reporting.)

Reordering

Finally OWAMP reports the amount of re-ordering it observed. A description of the metric used to report this can be found at:
http://www.internet2.edu/performance/owamp/draft-shalunov-reordering-definition-02.txt.html

OPTIONS

-h

Print a usage message and exit.

Output Options:

-a percentile_list

percentile_list indicates the list of quantiles to be reported out in addition to median. This is done by specifying a list of percentiles in a comma separated string (spaces are not allowed). Each percentile is indicated by a floating point value between 0.0 and 100.0.

This value is only used if reporting summary statistics.

-b bucket_width

A histogram of delays is created to compute the summary statistics. (This is used to compute percentiles of delay such as median.) The bucket_width indicates the resolution of the bins in the histogram. This value is specified using a floating point value and the units are seconds.

Because a histogram to compute the median (and other percentiles of delay) the results can be misleading if the bucket_width is not appropriate. For example, if all of the delays in the sample are smaller than the value of bucket_width then the median will be reported as bucket_width, a value that is greater than the maximum delay in the sample. To avoid this, bucket_width should be picked to be smaller than (max - min). The default value was selected to be reasonable for most real network paths, it is not appropriate for tests to the localhost however.

This value is only used if reporting summary statistics.

-d dir

dir indicates the directory in which to save summary files if the -p option is used.

-M

Print summary information in a more computer pars-able format. Specifically, values are printed out in a key/value style. Units are seconds for all time values.

The -M option is ignored if -Q is set.

-N count

Number of test packets to put in sub-session summaries when computing statistics on owamp session data.

This option is used to break down the summary statistics in smaller sample sizes than a complete owp file. This is useful when breaking up very long running sessions.

This option is only used for statistical output, and therefore has no effect on the -R output mode.

-n units

units indicates what units time values should be reported in. units is specified using a single character specifying the units wanted.

-p

Save output summary information into files instead of printing it to STDOUT. Also, print the names of the files to STDOUT. The files will be saved in the directory specified by the -d option.

The summary filenames are in the format:

${START_TIME}_${END_TIME}.${FILETYPE}

STARTTIME and ENDTIME are the start and end timestamps for the session or sub-session. The timestamps are ASCII representation of 64 bit integers with the high-order 32 bits representing the number of seconds since Jan 1, 1900 and the low-order 32 bits representing fractional seconds. The FILETYPE is sum for -M summary files, and txt for the default human-readable summary information.

This option is ignored if the -R option is specified.

-Q

Suppress the printing of all summary statistics and human-readable individual delays (-v).

-R

Print individual packet records one per line in the raw format:

-v

Print delays for individual packet records. This option is disabled by the -Q and -R options.

EXAMPLES

Report the summary statistics from the file datafile.owp.

owstats -a 5,95 datafile.owp

Report the summary statistics from the file datafile.owp. Also, report the 5th and 95th percentile of delay as an extra statistics.

owstats -R datafile.owp

Print out the packets in a more machine readable format with no statistics computed at all.

owstats -v datafile.owp

Show individual delays for each packet with summary statistics printed at the end.

owstats -M datafile.owp

Print out summary statistics in a more computer pars-able format.

owstats datafile1.owp datafile2.owp datafile3.owp

Print out summary statistics for multiple files.

SEE ALSO

ACKNOWLEDGMENTS