[asterisk-dev] Idea for GSoC: Support of PRACK in Asterisk

[Kevin P. Fleming]

Nic Bellamy wrote:

> A question for the Digium guys: what kind of license would be required 
> in order to use a third-party SIP library in a new SIP stack? Would an 
> LGPL library be usable?

I recently (as in a few months ago) went through the exercise of trying
to use the Sofia stack's SDP parser/generator in chan_sip. It wasn't
that hard to use, and it worked well.

However, since it is licensed under the LGPL, incorporating the Sofia
code *into* chan_sip won't work, as it doesn't fly with commercial
licensing of Asterisk. *Linking* to an LGPL library outside Asterisk,
though, is acceptable. In the case of the Sofia stack, this wasn't
practical, because it's not widely packaged by Linux distributions, so
it would be an inconvenience for users to have to download it from some
place, compile it and install it just to have SIP support in Asterisk.
Conversely, if we distributed it as part of Asterisk, even though it
might be compiled and installed separately, we'd risk infringing on the
'spirit' of the LGPL by just using a build-time split to try to avoid it.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: kpfleming at digium.com
Check us out at www.digium.com & www.asterisk.org