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

[Joshua Colp]

Gunnar Hellström wrote:
> On 2012-11-10 01:26, Russell Bryant wrote:
>> > With all of these in mind, what do you suggest the Asterisk project
>> does
>> > in order to use a third-party SIP stack?
> Before getting that far, carefully select the candidates and verify
> their multimedia capabilities.
>
> So many SIP stacks have begun as audio-only SIP stacks, and have got
> multimedia squeezed in late, resulting in a lot of unwanted behavior.
> Good behavior and good structure is needed from the beginning. This
> cannot be read in specs, it must be tested.

A SIP stack doesn't care about media really, that's handled above it in 
the application layer and conveyed using SDP. While some of the projects 
do have these higher level APIs for media and other things they wouldn't 
be used in the new SIP channel driver. The one I could foresee being 
used would definitely be SDP parsing and generation. I've looked at the 
various ones in the different SIP stacks and they are all done in a 
generic fashion. The application layer (which we would be implementing) 
is where all the smarts is.

Could the other extra APIs be useful later for other things? Sure, but 
that would be outside the SIP channel driver and shouldn't be considered 
a requirement in my opinion.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at:  www.digium.com  & www.asterisk.org