[asterisk-dev] Recommendations for using a SIP stack with Asterisk

[Tilghman Lesher]

On Tue, Nov 13, 2012 at 12:47 PM, Faidon Liambotis <paravoid at debian.org> wrote:
> On 11/13/12 20:10, Russ Meyerriecks wrote:
>> I don't know if any of this applies to the distribution model but as a kernel
>> developer, this is almost exactly the kernel's development process.
>
> Not at all. Linux is not a good comparison but since you've driven the
> argument there:
>
> Among all forks of the kernel, there are no differences in userspace
> API/ABI. Can I take a stock kernel and run it on my Debian system? Sure.
> Can I write an application on my Debian system and expect it to work
> (both as a source and a binary) in a RHEL system/kernel? Sure.
>
> Will I able to compile Asterisk against a stock pjsip? Unlikely.

Can you take a Debian kernel and run it on a RHEL system?  Unlikely.
How about a Red Hat Enterprise package and run it on Debian?  Probably
not without significant modifications.

>> 2) Asterisk only needs the sip stack bit of of an external library, not any
>> other surrounding layers.
>
> And what's the point then? No-one is forcing you to use 100% of all API
> calls of a library.

Because the SIP stack is likely going to need to be modified beyond
what the stock library provides.  The library provides a starting
point, but it is not completely sufficient to meet the end goals of
the applicaiton.

>> 3) Asterisk may need to modify the sip stack in non-standard ways, in order to
>> be compliant with non-standard devices. (to enhance user experience)
>
> Is this need to support non-standard devices unique to Asterisk? I don't
> think so, quite the contrary. How is "shared library" and "never
> deviates from the standard" synonymous?

It is not, but as argued before, many libraries will refuse patches
based upon implementation bugs in other hardware.  Interop is improved
by such patches, but many projects (including Debian, I might add)
value purity over interop.

-Tilghman