How to interpret "ping" commmand output?

Question

I have a problem with my dial-up internet connection from TATA Indicom. Randomly the web pages do not get downloaded.
If i try the "ping www.anywebsite.com" at these times, i get an output showing "25% data loss" or "50% data loss" like that.
What does this mean? Is the problem in my PC or ISP? Cannot be with the website because it happens on all websites.
The problem also is that this is not always present only for about 10 minutes/half hour then everything becomes normal. Then after sometime again recurs.
-SS.

Answer 1

sh-3.00# ping www.yahoo.ca
PING rc.yahoo.akadns.net (216.109.112.135): 56 data bytes
64 bytes from 216.109.112.135: icmp_seq=0 ttl=51 time=97.9 ms
64 bytes from 216.109.112.135: icmp_seq=1 ttl=52 time=35.4 ms
64 bytes from 216.109.112.135: icmp_seq=2 ttl=52 time=36.2 ms

--- rc.yahoo.akadns.net ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 35.4/56.5/97.9 ms
sh-3.00#


OK there is a typical UNIX ping output; similar to a Windows ping anyway in output.

3 p. transmitted: means my computer sent out 3 separate signals of Ping.
3 p. received: means 3 acknoledge signals corresponding to the 3 sent came back from rc.yahoo...
0% loss: just a statistical percentage representation on the former 2 numbers.

However, your ultimate aim is to ID the problematic link, ping will not be able to help you further beyond the existence of error in your connection, try netstat on UNIX.

Answer 2

ping has a timeout for each packet it sends. If the response is not received in time, it is presumed lost. Network conditions between your PC and the remote site can cause the response time to vary enough to let you experience the timeout sometimes, but not others. You can set the timeout on a Windows PC using the "-w timeout" option (use "ping -h" for help with the ping command).

Or, there could be network congestion on some link between your PC and the remote host, and some of your ping packets may actually be discarded as a result of that congestion. There's nothing you can do about that.