Re: Pinging a Device Every Second

[Tim Pozar <pozar () lns com>]

In one of my client's company, we use LibreNMS.  It is normally used to
get SNMP data but we also have it configured to ping our more "high
touch" cients routers.  In that case we can record performance such as
latency and packet loss.  It will generate graphs that we can pass on to
the client.  It also can be set to alert us if a client's router is not
pingable.

LibreNMS can also integrate Smokeping if you want Smokeping-style graphs
showing standard deviation, etc.

Currently I am running LibreNMS on a VM on a Proxmox cluser with a
couple of cores.  It is probing 385 devices every 5 minutes and keeping
up with that.  In polling, SNMP is the real time and CPU hog where ping
is pretty low impact.

Tim

On 12/15/18 9:37 AM, Baldur Norddahl wrote:
> You could configure BFD to send out a SNMP alert when three packets have
> been missed on a 50 ms cycle. Or instantly if the interface charges
> state to down. This way you would know that they are down within 150 ms.
>
> BFD is the hardware solution. A Linux box that has to ping 1000
> addresses per second will be very taxed and likely unable to do that in
> a stable way. You will have seconds where it fails to do them all
> followed by seconds where it attempts to do them more than once. The
> result is that the statistics gathered is worthless. If you do something
> like this, it is much better to have a less ambitious 1 minute cycle.
>
> Take a look at Smokeping. If you want a graph to show the quality of the
> line, Smokeping makes some very good graphs for that. 
>
> Regards 
> Baldur 
>
> 15. dec. 2018 16.49 skrev "Colton Conor" <colton.conor () gmail com
> <mailto:colton.conor () gmail com>>:
>
>     How much compute and network resources does it take for a NMS to:
>
>     1. ICMP ping a device every second
>     2. Record these results.
>     3. Report an alarm after so many seconds of missed pings. 
>
>     We are looking for a system to in near real-time monitor if an end
>     customers router is up or down. SNMP I assume would be too resource
>     intensive, so ICMP pings seem like the only logical solution.
>
>     The question is once a second pings too polling on an NMS and a
>     consumer grade router? Does it take much network bandwidth and CPU
>     resources from both the NMS and CPE side?
>
>     Lets say this is for a 1,000 customer ISP.