ASSOLO is a new active probing tool for estimating available
bandwidth based on the concept of "self-induced congestion".
The tool features a new probing traffic profile called REACH
(Reflected ExponentiAl Chirp), which tests a wide range of
rates being more accurate in the center of the probing interval.
Moreover, the tool runs inside a real-time operating system and
uses some de-noising techniques to improve the measurement process.



GENERAL OVERVIEW
================

This code uses REACH UDP-trains of packets to estimate available
bandwidth (aka unused capacity) of a network path.

Instead of reinventing the wheel, ASSOLO re-uses the basic
low-level network packet sending functions of pathChirp 2.4.1,
another great measurement tool devoleped by Vinay Ribeiro,
Ryan Christopher King and Niels Kang Hoven (Rice University).

The SENDER (assolo_snd) and RECEIVER (assolo_rcv) modules run as
daemons on hosts at opposite edges of a path to be probed. Packet
trains travel from the SENDER to the RECEIVER.

We initiate the assolo probing using a third module, assolo_run,
which can be run on any host (called the MASTER). This module also
collects the results of the experiment and stores them in a file
locally. Thus experiments can be initiated and the results analyzed
from a central location in the Internet which runs the assolo_run
module.

The assolo_snd and assolo_rcv modules can be started on
different machines around the Internet and will run indefinitely. They
need not be restarted for each experiment.


	         chirps
     SENDER ----------------> RECEIVER (assolo_rcv)	
   (assolo_snd)			 |
			  	 |		
      			      MASTER (assolo_run)
                 (starts experiment/collects results)



INSTALL INSTRUCTIONS
====================
Run the following:

1) autoconf
2) ./configure   
3) make

                                                                             
The following binaries will be generated:

Bin/<host_cpu>/assolo_rcv
Bin/<host_cpu>/assolo_snd
Bin/<host_cpu>/assolo_run

For example on your Linux box could be <host_cpu>=i686.



RUNNING EXPERIMENTS
===================

1) SENDER (needs to be run just once)

Bin/<host_cpu>/assolo_snd 

Options:
	 -U <sender port, default=8365>
	 -h help (produces this output)
	 -v version
	 -D print debug information

NOTE ON PORT NUMBER: In case the default port number is already used
at the sender, try out other port numbers larger than 1024 using the
-U option.  The receiver must then use the same port number with the -U 
option.

2) RECEIVER (needs to be run just once)

Bin/<host_cpu>/assolo_rcv

Options:
	-h Help
	-v Version
	-D print debug information 


3) MASTER (needs to be rerun for each experiment) 

Bin/<host_cpu>/assolo_run -S <sender> -R <receiver> -t <expt. duration (secs)>

 ** In case of interrupt coalescence on Gigabit networks use the -J option:
Example:
Bin/<host_cpu>/assolo_rcv -S <sender> -R <receiver> -t <expt. duration (secs)> -J 6


All Options:

	 -n  <number of estimates to smooth over, default=11>
 	 -d  <decrease factor (>1), default=1.5>
 	 -b  <busy period length (integer >2), default=5>
 	 -U  <receiver port (chirp UDP), default=8365 (1024-65535)>
 	 -h  help: produces this output
	 -S  sender host name or IP address 
	 -R  receiver host name or IP address 
	 -J  number of packets per Jumbo packet,default=1. In case of packet coalescence use values larger than 1, e.g. -J 6 
	 -l  lowest rate (Mbps) to probe at within chirp, default=10.000000Mbps. NOTE: by default assolo will find an appropriate probing range.
	 -u  highest rate (Mbps) to probe at within chirp, default=200.000000Mbps
	 -p  packet size <40-8200>,default=1000 bytes
	 -t  duration of experiment(sec), default=600 sec 
	 -s  spread factor: ratio of consecutive inter-arrivals within a chirp, default=1.2 
	 -a  average probing rate (Mbps), default=0.3Mbps 
	 -v  version
	 -e  treshold (default 5%)
	 -f  filter (default type 0 - Vertical Horizontal Filter)



RESULTS
=======

At the MASTER, the file

 <sender_name>_<receiver_name>_<time stamp>.instbw

will be generated in the directory from which the code is run.


FORMAT of the file: 

 <time_stamp> <avail-bw estimate (Mbps)>


Measurements _should_ be in chronological order. However, we suggest
to sort them using the standard *nix tool 'sort'.

An easy way to see results is to plot them. A simple script like:


close all; clear all;

trace = load('trace_filename.instbw'); % change filename here!
trace = sortrows(trace, 1);
time = trace(:, 1);
time = time - time(1)
avail_bw = trace(:, 2);

plot(time, avail_bw);
hold on;
set(gca, 'YLim', [75 100], 'XLim', [0 30]); xlabel('Time'); 
ylabel('Available Bandwidth');


enable you to see measured available bandwidth using Octave/Gnuplot.



CORRESPONDENCE
==============

Please do send your comments about the performance of this available
bandwidth estimation tool, and any changes you feel would make the
tool more convenient or user friendly.

Contact: Emanuele Goldoni, [email protected]