Sorry if this a double post... I swear I submitted this already but I didn't see it...oh well.

Can anyone tell me:

a) What DURATION of 100% packet loss MIGHT drop VOIP calls?

b) What DURATION of 100% packet loss WILL drop VOIP calls?

What exactly am I talking about:

I recently changed some VOIP hardware and found occurances of dropped calls. PP is set to ping at .5 second intervals. Out of 1000's of pings I spotted a couple of drops at the final destination lasting 500ms (1/2 second) to 1500ms (1.5 seconds.) These corresponded down to the second to some of the reported times of dropped calls. Before you ask, there is nothing interesting happening right before these drops... ie...no other loss and no high latency.

As far as I can tell the connection is excellent with 0% PL 99.x% of the time with the very occasional hiccup as above. I don't think the connection characteristics have changed so it would make sense that something is flaky with the different hardware. I did find one cause of the packet loss being at my BSD router itself... I had 2 X NICs sharing one IRQ which is known to cause occasional interface problems but that's besides the point.


THANKS!

I think this is very implementation specific. Obviously, a 100% packet loss duration will make you unable to hear anything, but dropping the call is quite another story.

I'm at home right now, and I have a Lingo VoIP router. I disconnected a network cable for 30 seconds and the phone call was still going when I reconnected the cable (I tested this calling our local ski report recording).

I'd recommend testing this yourself - just disconnect a network cable and see what happens (of course, you'll need to disconnect a cable that doesn't signal the VoIP hardware/software it needs to reset, and doesn't do any long-running DHCP retraining or anything).

If your packet loss is being caused by a piece of hardware on your own network that is signaling your VoIP system that it needs to "retrain", then I can imagine any length of outage would drop calls (as short as 1/2 second? sure). One example of this might be if you unplug the network cable of your VoIP hardware itself. It's going to want to re initialize the network card, re query the DHCP server, and who-knows-what-else to get things going again. That would probably cause a call to be dropped.

In most conditions, though, 1.5 seconds of dropped packets is *WAY* *WAY* too short to drop a call for.

You'd need to talk to your VoIP hardware / software vendor to get concrete answers about dropping calls vs total packet loss periods.

- Pete