[asterisk-dev] Subscription Persistence Issues

[George Joseph]

On Wed, Feb 8, 2017 at 6:56 AM, Joshua Colp <jcolp at digium.com> wrote:

> On Tue, Feb 7, 2017, at 03:16 PM, George Joseph wrote:
> > Greetings All,
> >
> > I've been working on the (many) issues with recreating inbound
> > subscriptions after an asterisk restart.  I have an approach that works
> > but
> > has a drawback:  We can recreate the subscription on startup from the
> > data
> > we persist and can even send a NOTIFY to each subscriber BUT with the
> > current version of pjproject, we can't actually set the expiration timer.
> > I have a pjproject patch ready that allows us to set tie timer but the
> > drawback is that this approach will only work with bundled pjproject or a
> > patched version of your own.
> >
> > There's an alternative though...   When asterisk restarts, instead of
> > sending 'active' NOTIFYs to each subscriber, we could send
> > 'terminate,probation' instead.  The RFCs say that a "client SHOULD retry
> > at
> > some later time".  While this approach will work with any version of
> > pjproject there are issues here as well.  The first issue is the word
> > 'SHOULD'.  There's no guarantee that the client will actually
> > resubscribe.
> > The second issue is the extra SUBSCRIBE/OK/NOTIFY/OK exchange between
> > asterisk and the client at startup.  We can tell the client to retry not
> > before a random interval similar to how we stagger sending OPTIONS
> > messages
> > at startup but it's still an extra 4 packets per subscription.
>
> I don't trust clients enough to expect that this behavior will work for
> everything. If we can do the work ourselves in a way that guarantees it
> works for all clients I usually opt for doing that.
>

Yeah after further investigation, "some manufacturer"''s phones don't
resubscribe on a deactivated or probation reason.  Also discovered another
bug in pjproject that prevents the use of the 'retry-after' parameter with
probation.

I think the approach will have to be that if we detect that patched
pjproject is in use, we use the pjproject timer and if not, we start our
own timer.



>
> --
> Joshua Colp
> Digium, Inc. | Senior Software Developer
> 445 Jan Davis Drive NW - Huntsville, AL 35806 - US
> Check us out at: www.digium.com & www.asterisk.org
>
> --
> _____________________________________________________________________
> -- Bandwidth and Colocation Provided by http://www.api-digital.com --
>
> asterisk-dev mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-dev
>



-- 
George Joseph
Digium, Inc. | Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-dev/attachments/20170208/b42f2ad4/attachment.html>