[asterisk-dev] Viva Chan_Sip, may it rest in peace

[Corey Farrell]

Many people don't like chan_sip, most people hate working with the code.
The rush to throw out chan_sip when PJSIP isn't ready to be the only SIP
stack annoys me a bit.  Nobody is forcing anyone to use or contribute to
chan_sip.  Digium changed chan_sip from core to extended support so they
can significantly reduce involvement.  At some point chan_sip will fizzle
out but that hasn't happened yet.

Last time I checked about 200 of the PJSIP testsuite tests produced AO2
leaks, in many cases hundreds of objects were leaked [1].  Some of these
leaks may be caused by bugs in tests and I realize that many use cases must
work without major leaking, but some use cases could cause failures.  I've
submitted some fixes but I find PJSIP leak tracing more difficult than
other parts of Asterisk.

The current policy of allowing new features into released LTS branches is a
concern for me with PJSIP.  If I were to start using PJSIP I would have to
worry about each 13.x.0 release having a new PJSIP feature possibly cause a
bug.  A lot of bad things can be said about chan_sip, but new features are
extremely unlikely in 13.12.0.  It would be nice if a core set of PJSIP and
other modules could be declared LTS frozen.  During LTS releases these
modules would be strictly bug fix only.  I suspect this is not yet wanted
or possible for PJSIP modules, but hope it can be re-evaluated before new
LTS branches.  My hope is that eventually a basic PJSIP PBX could be run
using only frozen modules.  Users with a specific needs or higher risk
tolerance could run some / all of the unfrozen modules to get more advanced
or less mature features.  Eventually the list of frozen modules could grow
as each module becomes feature complete and is proven stable.

I do see chan_pjsip in my future.  It has all the features I need plus the
config handling will improve my handling of dynamic peers.  I have no
timeframe to migrate as I can't ignore my concerns and they can't be
addressed overnight.

[1] https://jenkins.asterisk.org/jenkins/job/periodic-ref_de
bug-asterisk-13/8/

On Tue, Oct 4, 2016 at 8:46 PM, James Finstrom <jfinstrom at gmail.com> wrote:

> So the discussion of deprecating chan_sip came up at the devcon this year
> and it caused a bit of a stir. The end result was the need for broader
> discussion with a wider audience.  So let's discuss.
>
> Currently, Asterisk is running dual sip stacks. The argument is that to
> deprecate PJSIP there must be broader adoption. There is currently nothing
> motivating adoption but much slowing it.
>
> What are some of the hurdles to adoption?
> 1. Apathy.  If it ain't broke don't fix it. Many would argue chan_sip is
> broke but it is the "devil you know". A decade of documentation and a broad
> user base allows people to be pretty forgiving of flaws. Almost any issue
> has some sort of work around or generally accepted idea of I guess we can
> live with it.
>
> 2. One Ring to rule them all!!  PJSIP requires up to 6 sections of
> configuration. Once you dig in, this method makes sense. But at a glance,
> you have just multiplied the workload to  6 times that of chan_sip's single
> blob config. Though it is not really 600% more effort it may be enough to
> scare some away
>
> 3. Mo Adoption, Mo problems!
> The only way to clean up all the edge cases and weird bugs is to hit them
> in the first place.  Dogfooding only gets you so far.  You can make
> anything working clean in a single environment and single use case. But
> what happens when people start flinging wrenches. Things break. 100
> wrenches may break 10 things. 1000 wrenches may break 100 things.  In the
> ladder case, you have 100 people saying pjsip sucks, and pjsip is crap. As
> with all things the 900 assume all is good and move on with their lives
> telling no one of their glory. So you have 10% of the voices running
> unopposed. You fix the 100 issues and that is great but those 100 people
> have gone back to the comfort of chan_sip and are stuck at point 1.
>
> Escaping the cycle.
>
> So how do we dredge through this mess and get high adoption?
>
> You have to make #1 not an option.  This means potentially breaking the
> universe. This is why I think there is a tendency to be gunshy. No one
> wants to be the guy who broke the universe.  But breaking the universe gets
> us to #3 without falling back into #1.   Once The universe breaks and we
> are in #3 many of the edges will be found and fixed. Suddenly PJSIP becomes
> usable in most, if not all situations. The issues in #2 will automatically
> resolve as there is more information and it becomes the "accepted way" of
> doing things.  The old dogs will have to refactor how they do configuration
> but I am confident once they do a few they will figure out the bark is
> bigger than the bite.
>
> tl;dr to get adoption you have to force it.  There will be blood, but
> nothing that can't be cleaned up with a little bleach and some elbow grease
>
> --
> James
>
> --
> _____________________________________________________________________
> -- 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
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-dev/attachments/20161007/7f5cfedf/attachment.html>