Satellite link statistics
This page is a generalized version of Greg Lehey's
page showing his problems with the IPStar satellite. See that page for more details and how to
get the software.
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.
Click on the graphs for a 1600x1200 version.
