[asterisk-users] Purpose of qualify=yes

[Chris Owen]

On Sep 16, 2010, at 10:45 AM, Zeeshan Zakaria wrote:

> I prefer to keep qualify=on for all the extensions, as it gives you an idea which extensions are going to give you trouble. For extensions with qualify value greater than 300 ms you should definitely worry. For extensions at 2000ms delay or more, turning qualify off simply means to ignore the obvious problem. Such extensions have communication or network issues which require serious attention. You can set this parameter to, e.g. 3000 ms or more if dealing with 2000 ms delay is unavoidable, but don't turn it off. Afterall even at 2000 ms conversation is not truly real time and not easy.

In our case the problem isn't that the phones are experiencing high latency per se but rather than a full pipe plus all these SIP messages is playing hell with the QOS stuff.

20 phones in one location times say 4 SIP packets every 2 seconds equals 40 SIP packets a second.   That normally isn't a problem but when the pipe gets congested then we start seeing issues when a call comes in and 400 BLF notices go out etc.  Obviously we can increase the amount of bandwidth reserved for SIP traffic but I'm just not sure why we're sending all those packets in the first place.

In other words, the qualify traffic is actually causing the problem, not revealing it.

Chris