I'm pleased to announce the release of FlowScan-1.005. FlowScan
is a tool to monitor and graph flow information from Cisco
routers in near real-time.
Amonst many other things, FlowScan optionally measures and
graphs traffic for applications such as Napster. A sample of
what FlowScan can do is at:
Changes in FlowScan-1.005 (since FlowScan-1.003)
* A major performance enhancement was done resulting in FlowScan
being about twice as fast as earlier releases. For instance,
on a 600 MHz PIII, FlowScan can process about 3400 flows-
per-second vs. 1700 previously. This was managed by changing
the CampusIO and SubNetIO report modules to use the Patricia
Tries algorithm for all IP address-based lookups. The
Net::Patricia perl module is now required.
* The "graphs.mf" template Makefile was improved to introduce some
new "io" graphs, which show outbound traffic above the axis
and inbound traffic below. These graphs are based on
examples by <Alexander.Kunz@nextra.de>. Also, the option to
produce PNG or GIF files was added to the "graphs.mf"
* The `UDPServices' option was added to CampusIO. This directive
allows one to specify which UDP traffic should be measured,
similarly to the CampusIO `TCPServices' option.
* A new features was added to CampusIO which causes it to write
flows for "other" applications (i.e. unidentified apps) to
time-stamped raw flow files in a directory called
"saved/other" if that directory exists. This simply makes it
easier to study which flows are not being identified by
service or application.
* A routine was added to CampusIO that periodically purges old
Real media servers from the hash cache used to identify Real
media traffic. Previously this cache would grow without
* Tested cflowd patch with cflowd-2-1-a9.
FlowScan is licensed under the GNU General Public License, and
is available to you at:
There are two mailing lists having to do with FlowScan:
a general mailing list for FlowScan users.
a low-volume, restricted post mailing list to keep FlowScan
users informed of news regarding FlowScan.
The lists' respective archives are available at:
Announcements will be "cross-posted" to both lists, so there's
no need to join both.
These lists are hosted by the Division of Information
Technology's Network Engineering Technology group at the
University of Wisconsin - Madison. To subscribe to either of
them, send email to:
You should receive an automatic response that will request that
you verify your request to become a member of the list, to which
you must reply with the authentication information there-in.
Then, in response to your reply, you should receive a welcome
message. If you have any questions about the administrative
policies of this list's manager, please contact:
If you're interested in Napster specifically, note the graph
labeled "Well Known Services Mb/s" here:
or, directly, here:
I have written a general document about the Napster portion of
the measurement at:
Some related research on Napster flows is at:
Alexander Kunz <Alexander.Kunz@nextra.de>
Kevin Gannon <firstname.lastname@example.org>
John Payne <email@example.com>
I'd like to thank the FlowScan beta testers (since September
1999), early users, and participants in the FlowScan mailing
list for their efforts and feedback.
Also, thanks to Daniel McRobb, Tobi Oetiker, and CAIDA for
providing the main tools upon which FlowScan is built, namely
"cflowd" and "RRDTOOL".
Copyright and Disclaimer
Note that this document is provided `as is'. The information
in it is not warranted to be correct. Use it at your own
Copyright (c) 2000 Dave Plonka <firstname.lastname@example.org>.
All rights reserved.
This document may be reproduced and distributed in its
entirety (including this authorship, copyright, and
permission notice), provided that no charge is made for the
-- email@example.com http://net.doit.wisc.edu/~plonka ARS:N9HZF Madison, WI -- cflowd mailing list firstname.lastname@example.org
This archive was generated by hypermail 2b29 : Thu Oct 19 2000 - 14:07:40 PDT