AN AD-HOC TESTBED MONITORING WITH RRDTOOL

AN AD-HOC TESTBED MONITORING WITH RRDTOOL

Ad-Hoc Testbed configuration

The Ad-Hoc testbed includes 5 mobile nodes: 2 desktops, 2 laptops and one PDA with wireless LAN card (Orinoco). The MP3 client and server are resided on 2 desktop ( as showed in figure 7). The PDA and two laptop will be relayed nodes. When MP3 streaming is initiated the routing path will be changes between PDA and Laptops depende 141b11b nt on it residual energy and position. During the testbed we use RRDTool for monitoring the traffic, Signal and Noise and SNR at each node.

Figure : Ad-Hoc Testbed configuration

RRDTool setup and configuration

a.     Installing RRDTool

In each Ad-Hoc node we install an Apache server with the root address is: "/var/www/html". The latest version of RRDTool is available at: ftp://ftp.mirrors.wiretapped.net/pub/rrdtool/rrdtool-1.0.45.tar.gz

Copy the tarball into the "/usr/src" directory on wer linux box. From a command prompt, change into the "/usr/src" directory, and un-tar the tarball:

root@192.168.120.2# cd /usr/src

root@192.168.120.2# tar -xzvf rrdtool-1.0.45.tar.gz

Change into the newly created directory:

root@192.168.120.2# cd rrdtool-1.0.45

Compile and install RRDTool:

root@192.168.120.2# ./configure

root@192.168.120.2# make

root@192.168.120.2# make install

The default installation location is "/usr/local/rrdtool-1.0.48", so make some symbolic links to the executables:

root@192.168.120.2# ln -sf /usr/local/rrdtool-1.0.45/bin/rrdtool /usr/bin/rrdtool

root@192.168.120.2# ln -sf /usr/local/rrdtool-1.0.45/bin/rrdupdate /usr/bin/rrdupdate

root@192.168.120.2# ln -sf /usr/local/rrdtool-1.0.45/bin/rrdcgi /usr/bin/rrdcgi

The RRDTool Perl library simplifies things when using RRDTool from a Perl script, so to compile and install the Perl library for RRDTool:

root@192.168.120.2# make site-perl-install

Create a directory for RRDTool databases, and a directory for the web images which it'll generate:

root@192.168.120.2# mkdir /var/lib/rrd

root@192.168.120.2# mkdir /var/www/html/rrdtool

b.     Getting Data

The first task is to determine how to obtain the data we want to insert into the RRD database. Some shell scripting can easily be used to obtain the items of information required. The statements below will return the SNR, signal, noise and rate respectively (assuming wer wireless interface is eth2).

root@192.168.120.2# iwconfig eth0|grep Quality|cut -d":" -f2|cut -d"/" -f1

root@192.168.120.2# iwconfig eth0|grep Signal|cut -d":" -f3|cut -d" " -f1

root@192.168.120.2# iwconfig eth0|grep Signal|cut -d":" -f4|cut -d" " -f1

root@192.168.120.2# iwconfig eth0|grep Rate|cut -d"M" -f1|cut -b20-24

Run these from a command prompt to verify they return the values expected.

c.     Automating Data Collection

To automate data collection, we use a Perl script which performs the following tasks:

create RRD database

retrieve data

store data into the RRD database

generate daily, weekly, monthly and yearly graphs

The source code of this file is showed in appendix [2]. Then this file is copied to "/usr/local/bin/" and make it executable by changing the file permissions on it:

root@192.168.120.2# chmod 755 /usr/local/bin/rrd_wlan.pl

and adjust the settings defined at the top of the script to make them appropriate for wer linux box (and make sure these directories exist):

# define location of rrdtool databases

my $rrd = '/var/lib/rrd';

# define location of images

my $img = '/var/www/html/rrdtool';

The following lines in rrd_traffic.pl specify for which wireless network interfaces data will be collected. Add/modify/delete any lines here as appropriate (lines can be commented out with a "#" character).

# process data for each interface (add/delete as required)

&ProcessInterface("eth1", "MartinMast link");

The linux box I'm running this on has a single wireless interface, which is eth0. If we have more wireless interfaces, just duplicate the line shown above, and adjust the values as required.

Also specify the description of each interface. This description will be printed on the top of each graph generated by this script.

Test the script by executing it from a command prompt:

root@192.168.120.2# /usr/local/bin/rrd_wlan.pl

The first time the script is run, it'll create an RRD database for each interface, so we should see output similar to this (assuming the script has been configured to monitor eth1):

root@192.168.120.2# /usr/local/bin/rrd_wlan.pl

eth0 link stats: snr: 9 dB, signal: -94 dBm, noise: -103 dBm, rate: 2 Mbits/s

creating rrd database for eth0 interface...

On any subsequent executions, we should see similar output, but without the creating rrd database...... line.

Once we've verified the operation of the script, it can be automatically scheduled to run periodically. To get it to run every 5 minutes, add the following to "/etc/crontab":

# get wireless link details

*/5 * * * * root /usr/local/bin/rrd_wlan.pl > /dev/null

Note that if we find wer graphs are being created, but with no data, it's probably because wer cron paths aren't setup to include paths to all of the shell commands used in rrd_wlan.pl. To correct this, we'll have to either:

edit "/usr/local/bin/rrd_wlan.pl" to reference the full pathname for iwconfig, cut and grep, or edit the PATH definition in "/etc/crontab" to include the paths of those commands.

d.     Viewing the Graphs

Each time the script is executed, if required, it'll update the graphs of SNR, signal, noise and the link rate. These graphs are being created in "/var/www/html/rrdtool/", and assuming we've got a webserver running, they'll be accessible via "https://192.168.120.2/rrdtool/". To provide a much cleaner way to view these graphs, we can develope a simple webpage for displaying all the daily trends, as well as displaying the daily, weekly, and yearly trends when a user clicks on one of the daily trends. We can save it as wlan.cgi file in directory: "/var/www/html/rrdtool/". Then make it executable by changing the file permissions on it:

root@192.168.120.2# chmod 755 /var/www/html/rrdtool/wlan.cgi

and adjust the settings defined at the top of the script to make them appropriate for wer linux box, in particular, the interface name:

# define the wireless interface

my $iface = 'eth0';

# get the server name (or we could hard code some description here)

my $svrname = $ENV;

e.     Comments on Data Storage

This script uses a single RRD database to hold the SNR, signal, noise and link rate details for the wireless interface. The rrd_wlan.pl script uses the following syntax to create the RRD database:

rrdtool create /var/lib/rrd/weth0.rrd -s 300  \

DS:snr:GAUGE:600:0:60 \

DS:signal:GAUGE:600:-256:0 \

DS:noise:GAUGE:600:-256:0 \

DS:rate:GAUGE:600:0:100 \

RRA:AVERAGE:0.5:1:576 \

RRA:AVERAGE:0.5:6:672 \

RRA:AVERAGE:0.5:24:732 \

RRA:AVERAGE:0.5:144:1460

This will create an RRD database with the following attributes:

5 minute step (base interval with which data will be fed into the RRD), 4 data sources (snr, signal, noise, rate), 10 minute heartbeat for each data source

2 days of 5 minute averages

2 weeks of 1/2 hour averages

2 months of 2 hour averages

2 years of 12 hour averages

Monitoring results

In this report we shows the monitoring result at a relay nodes when it belong to a routing path of a MP3 streaming. This node has IP address is: 192.168.120.2 ( For showing the result we public it on the Internet via the address: https://220.69.183.102/RRDTool/)

a.     Forwarding traffic

Daily Graph (5 minute averages)

Weekly Graph (30 minute averages)

Monthly Graph (2 hour averages)

Yearly Graph (12 hour averages)

b.     Signal to Noise Ratio

Daily Graph (5 minute averages)

Weekly Graph (30 minute averages)

Monthly Graph (2 hour averages)

Yearly Graph (12 hour averages)

c.     Signal and Noise

Daily Graph (5 minute averages)

Weekly Graph (30 minute averages)

Monthly Graph (2 hour averages)

Yearly Graph (12 hour averages)

d.     Link rate

Daily Graph (5 minute averages)

Weekly Graph (30 minute averages)

Monthly Graph (2 hour averages)

Yearly Graph (12 hour averages)

APPENDIX

[1] wlan_rrdtool.pl source code

[2] wlan.cgi source code