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| Greg's satellite
link statistics |
| Download page |
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This page describes in more detail the scripts which create my satellite Internet monitoring page. This is effectively an HTML
markup of the README file in the distribution.
Download
The scripts are here. Before downloading them, read on to
see if you can use them or not.
What it is
This is an adaptation of the scripts I have written to monitor my own network connections. The
graphs show:
-
Link status. This is the connectivity to the other end of the satellite link, measured by
an ICMP echo (ping) packet once a minute. This should remain steady at 1. A drop to 0
indicates a link failure.
-
Network status. This is the number of remote systems responding to a ICMP echo (ping)
packet at the same time as the link status ping. I currently ping 5 systems which I
frequently access: freefall.FreeBSD.org, shell.mysql.com, www.auug.org.au, ozlabs.org and
ftp.NetBSD.org. Normally this value should be 5. If it's less, the script retries every
second until full connectivity is restored.
-
TCP transfer speed. This is a reciprocal function of the time it takes to transfer a very
small “web page” (four bytes) from Greg's external web server—see the right
hand side of the plot for the scale. The values shown are reciprocal seconds: 0.5 is 2
seconds, 2 is 0.5 seconds, etc. It seems that it takes about 4 seconds to perform the
transfer, which is due mainly to satellite latency and connection setup and closing
down.
These scripts work on FreeBSD, Linux and Apple Mac OS X. The installation makes some
assumptions; it's probably best to run it as I have tested it, though feedback and improvements
are welcome.
Prerequisites
I've only tried this on FreeBSD, Linux (Debian) and Mac OS X. I expect the scripts will work
just as well with NetBSD or OpenBSD. They won't work with Microsoft.
You'll need to install gnuplot to perform the
plots. Linux installations also need wget.
Installation
The archive itself is gzipped tar. It's intended for installation in a subdirectory called
satstat. To install, change to your home directory and extract:
$ cd
$ tar xzvf satstat.tar.gz
This creates the directories satstat, satstat/data and satstat/html and
populates them. The files are:
| README |
|
This file |
| config |
|
Basic configuration. You'll need to change some of the entries to match your system.
Details are in the file. |
| crontab |
|
Draft entries for crontab to run the plotting scripts at regular intervals. |
| getsatstats |
|
A script to create the graphs at regular intervals. I run this every 10 minutes via a
cron job. |
| getsatstats.week |
|
A script to create the graphs once a day. I run this in the early morning via a cron
job. This second file is needed because after collecting a fair amount of data, it can run
for a very long time. |
| linkcheck |
|
The main script to perform the tests. |
| satplot |
|
Raw gnuplot commands to perform the 4 hour and 24 hour graphs. This is processed into a
real file by the getsatstats script. You don't need to do anything with this file unless
you change your directory structure. |
| satplot.all |
|
Raw gnuplot commands to perform the weekly and 3 monthly graphs. This is processed into
a real file by the getsatstats.all script. You don't need to do anything with this file
unless you change your directory structure. |
| tcpcheck |
|
Script to test the TCP connectivity, invoked by linkcheck. You shouldn't need to do
anything with this file. |
The directories data and html are populated by linkcheck and
getsatstats* respectively. As supplied, there are some empty files and the file
satstats.html, which contains the text and links to the graphs.
Configuration
You'll need to modify the file config to suit your local configuration. Read the
instructions in the file. If you use cron to run the plot scripts, you'll need to copy
the data in the file crontab to your crontab, and also to modify it for your
installation. Again, the instructions are in the file.
Collecting data
Run the data collection script linkcheck without any parameters:
$ cd satstat
$ ./linkcheck &
It runs in the background; you don't need to do anything else.
The best way to run the plots is via crontab. Read the instructions in the file
crontab. If for some reason you don't want to do this, run getsatstats when you
want an update, and getsatstats.week after the first day of collection. Due to brain
damage in getsatstats.week you shouldn't run it more than once a day, or it will leave
holes in your daily graphs.
Viewing results
Look at the file html/satstats.html with a web
browser. The link shows what you should expect to see, but it's not the same as the real file
in the distribution. If you're running a web server, you can create a symbolic link to the html
directory.