[asterisk-dev] qualify= meaning in sip.conf ?

[John Lange]

On Tue, 2007-07-31 at 01:30 -0700, Luigi Rizzo wrote:

> Given that keeping dynamic entries alive is a real need, we need
> a way to adjust the period of OPTION, or a way to implement
> keepalives (which are less expensive for both the sender and the
> receiver, as they don't require the creation and parsing of a full message).

JFYI, this has been discussed on the list before.

Back then I suggested that qualify should be split into two separate
parameters; qualify & keepalive.

Qualify can continue to do what it does today (monitor the keep alive
message to determine if a device is reachable), and keep-alive can
determine the rate at which messages are sent.

Qualify would require keep-alive be set but keep-alive does not require
qualify.

In that way asterisk can send keep alive messages but not care if they
are ever returned.

Someone else in the thread pointed out that the whole qualify/keep-alive
system needs to be re-worked so that the scheduling of the messages is
spread out evenly.

However, since that discussion took place I have stopped using
Asterisk's qualify in favor of using the device's built-in keep-alive.
Many devices now implement their own keep-alives and in my experience
that works much better.

However, that is no reason not to improve Asterisk's system if you are
motivated to do so.

Regards,

John