Ping reply time

SysMgr · Post by **SysMgr** » Tue Jul 25, 2006 1:41 pm

I have a ping test on a host that typically has a reply time of 10ms or less. Host monitor (v6.10) returns a reply time of 0. Is this what I should expect? When I do a ping using command line tools in Windows or 'nix, or your IP Tools I get 9 to 10ms on this host.

Thanks in advance

KS-Soft · Post by **KS-Soft** » Tue Jul 25, 2006 2:18 pm

We have not changed code of the ping test in version 6. Truth to say I do not see a problem here, +- 10 ms is matter of calculation...
Does it report 1000 ms instead of 500ms?

Regards
Alex

SysMgr · Post by **SysMgr** » Wed Jul 26, 2006 9:28 am

The ping reply time for this host, which usually runs 9 to 10ms, is being reported as 0ms. There are occasions when the reply time goes above that but the smallest increment of time being reported as something other than "0" is 15ms. A line from the log: "7/25/2006,122217,0,Salem Ptr ping,1,Host is alive,0 ms,0,0,ping (timeout - 2000 ms)"

I don't understand what you're trying to ask in your last sentence.

Steve

KS-Soft · Post by **KS-Soft** » Wed Jul 26, 2006 9:30 am

I am trying to say that I do not see a problem

Regards
Alex

SysMgr · Post by **SysMgr** » Wed Jul 26, 2006 12:11 pm

My reason for bringing the issue up is that I would have expected Host Monitor to report the actual reply time not something +- 10ms of that time. So when it did, I assumed that something was wrong. Since you purposely set out to have it report a time +-10ms then I understand why you don't see it as a problem.

Thanks,
Steve

KS-Soft · Post by **KS-Soft** » Wed Jul 26, 2006 12:51 pm

Program cannot calculate 100% accurate time for physical processeses in the cable. Program needs some time to call Windows API, then Windows API allocates some memory, creates echo packet, then network card driver receives packet and so on and so forth. It has sense for any program, not only HostMonitor.
I think 10ms shorter interval can be caused by many reasons, for example
- faster CPU (if you have upgraded your system or target system)
- optimized software (e.g. you have updated network card driver on local or remote system)
- optimized memory allocation (e.g. you have restarted system)
- even disk defragmentation can lead to faster processing (e.g. Windows need less time to load icmp.dll when necessary).

If you start standard ping utility "ping 127.0.0.1", what do you see? It shows "time < 10ms". Why? Because its impossible to calculate PHYSICAL reply time with 0.0001 ms accuracy. Question is - do you really need such accuracy? If yes, then you need some very special software that will work in real time directly with network card. And you need such software on both (local and remote) systems.

Regards
Alex