STAB Software

[ General info | People | Papers&Presentations | Code]

STAB

General Info



STAB is a new active probing tool for locating thin links on a network path. A thin link is a link with less available bandwidth than all links preceding it on the path. The last thin link on the path is the link with the minimum available bandwidth or tight link. STAB combines the concept of "self-induced congestion", the probing technique of "packet tailgating", and special probing trains called "chirps" to efficiently locate the thin links. Another of our tools, pathChirp, is a precursor of STAB and estimates end-to-end available bandwidth.

People

Faculty:
Richard Baraniuk, Rudolf Riedi

Students:
Vinay Ribeiro

Acknowledgments:
Young Hyun (CAIDA)

Papers & Presentations

Paper
Vinay Ribeiro, Rudolf Riedi, and Richard Baraniuk
Locating Available Bandwidth Bottlenecks, IEEE Internet Computing, pp. 34-41, September-October 2004.
(This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders.)
PowerPoint Presentation
Spatio-Temporal Available Bandwidth Estimation, ISMA BEst Workshop, December 2003.

Code

System Requirements: UNIX/Linux on sender/receiver machines, filtering (i.e. discarding) of UDP traffic must not be enabled on an intermediate firewall or on the sender/receiver machines. This tool does not use ICMP packets.
Download either Gzip Compressed File(118KB) or Uncompressed File (522KB)
Steps to unpack file. All UNIX commands are in bold face. The outputs of certain commands are system dependent and are be denoted by square brackets [***].
- If you downloaded the Gzip Compressed File
  gunzip ./stab-1.3.1.tar.gz
  tar -xvf ./stab-1.3.1.tar
- If you downloaded the Uncompressed File
  tar -xvf ./stab-1.3.1.tar
  Start by reading the README file in the newly created subdirectory stab-1.3.1 or follow the instructions below.
Compiling code.
- cd ./stab-1.3.1
- ./configure
- make (on FreeBSD systems use gmake)
Recompiling code.
- cd ./stab-1.3.1
- make clean (on FreeBSD systems use gmake clean)
- ./configure
- make (on FreeBSD systems use gmake)
Running the code.
- cd ./Bin
- ls ./
  Let us call the result of this command [subdir]. Examples of [subdir] could be i686, i386, sparc and so on.
- cd [subdir]
  All the above commands must be run on both the machine that will send out chirp packets and the machine that will receive the chirp packets.
- On the machine sending out chirp packets run
  ./stab_snd
- On the sender machine receiving chirp packets run
  ./stab_rcv -S [sender machine name or IP address] -t 600
  On receiver machines with interrupt coalescence enabled use the following command for improved results
  ./stab_rcv -S [sender machine name or IP address] -t 600 -J 4
- At the receiver you will observe the output
  Opening file: [resultsfilename]
- After 600 seconds (10 minutes) the experiment would have ended. The results will be in the file [resultsfilename] at the receiver in the format
  [timestamp] [Available bandwidth estimate from source to some intermediate link number "l" in Mega bits/sec] [intermediate link "l"] [probability of link "l" being a thin link]
  
  NOTE:If you have gnome-config installed on your receiver machine then the results will be plotted in a window as shown below during the experiment. Two plots appear.
  Left plot This plot displays the available bandwidth from the sender node up to link "l" for different values of "l" (termed sub-path length). At the locations of "thin links" the plot typically drops by a significant amount. The last thin link is the link with the least available bandwidth on the path. The error bars in the plots reveal how accurate the estimates are. Smaller errorbars indicate more accurate estimates.
  Right plot This plot displays the estimated probability that different links are thin links.
  Initially no plots are displayed for a few minutes while STAB collects measurement data. Once the plots appear in the window they will update every 20 seconds with the latest results.
- To view the data in the results file, run the following at the receiver machine
  more [resultsfilename]
- To rerun the experiment you only need to restart the ./stab_rcv program at the receiver machine.

Please report any bugs or send comments regarding these programs to

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