On Wed, Feb 8, 2017 at 6:52 AM, Matthew Jordan <mjor...@digium.com> wrote:
> > > On Tue, Feb 7, 2017 at 1:16 PM, George Joseph <gjos...@digium.com> 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. >> >> Neither approach is harder or easier than the other to implement. It's >> just a matter of backwards compatibility vs extra traffic and the 'SHOULD' >> uncertainty. >> >> Thoughts? >> >> > If you go with the first approach, do the changes to pjproject to fix the > expiration timer issues cause any API changes? Or is it merely fixing a bug > in pjproject? > pjproject already has an internal API to set the timer on a subscription so the patch is creating a public wrapper for it. > > -- > Matthew Jordan > Digium, Inc. | CTO > 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA > Check us out at: http://digium.com & http://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
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