[asterisk-dev] OPAL and Asterisk

[Derek Smithies]

John,
 there is a big change in the way OPAL works, as compared to OpenH323.

To link asterisk to OPAL (as opposed to Openh323) would be a nice thing to 
have. You could make sip or h323 calls via the OPAL library. Thus, 
asterisk users would have the choice of sip stacks to use.

There have been several endeavours to get openh323 to link with asterisk. 
Some have been more successful than others. Currently, the effort seems to 
be to not use the openh323 library, and use thee objective h323 approach. 
This solves some license issues.

The API has changed, and a bit of C++ code would be required - all of it 
threadsafe. The OPAL library is designed to be highly threaded.

I think the trouble that the various openh323-asterisk integrations had 
was understanding and existing with the threading model of both projects. 
Others will give longer explanations, and alude to the defective 
programming in either codebase. These long explanations have come and 
gone, but are essentially developer speak for
        "I did not know enough to fix the problem"

The api docs for opal and openh323 are found at 
 http://www.voxgratia.org/documents.html

My preference is to use a woomera style approach. More can be found at
 http://www.voxgratia.org/docs/woomera_desc.html
The woomera approach solves license issues completely, and allows you to 
use g729 codec with a free version of asterisk.

Derek.

 On Thu, 1 Feb 2007, John T. Guthrie wrote:

> On Thu, 2007-02-01 at 12:13 -0800, Paul Cadach wrote:
> > If H.323 API in OPAL is not so different from OpenH323 one than it is easy 
> > to adapt existing chan_h323 to be able to handle both OpenH323 and OPAL.
> > 
> > Which version of Fedora do you uses? Currently I'm creating test beds for 
> > Asterisk and its chan_h323, so I can create additional VMWare virtual 
> > machine with your Fedora.
> 
> I am currently running FC6.  Would it be as easy as patching the
> configure script to find the include files and libraries, or are there
> slight API differences?
> 
> Thank again.
> 
> 

-- 
Derek Smithies Ph.D.
IndraNet Technologies Ltd.
Email: derek at indranet.co.nz
ph +64 3 365 6485
Web: http://www.indranet-technologies.com/