[Psi-devel] [ANN] Johnny Talker - revolution in creation of VoIP-based applications?

[Marcin Zajączkowski]

Justin Karneges wrote:
> Can IAX work without needing to set up some IAX server?  How effective is it 
> in getting around firewalls?

Yes it can. You just need to enter IP of your interlocutur. In that case 
(p2p) at least one side has to have public IP.
More sophisticated form is to set up own PBX (Private Branch Exchange, 
see http://en.wikipedia.org/wiki/Private_branch_exchange). With it, you 
are small "telecommunication provider" and people can call through this 
server even without public IP. Sample open source PBX is Asterisk 
(http://www.asterisk.org/). It's very advanced piece of software (see 
http://www.asterisk.org/features) and is used by real providers (with 
special hardware it's possible to call to PSTN ("normal" phones)). It 
allows (out-of-box to connect with users of SIP, H323, MGCP, SCCP and of 
course IAX :) ).
There is also many IAX providers all over the world which offers free 
call inside network (useful for people using Johnny Talker in Psi and in 
other clients and very cheap calls to many countries.
Comming back to subject IAX is VERY firewalls and NAT friendly. It uses 
only one port (for control and data stream) and almost never needs to 
reconfigure firewall.

> The main reason a Jabber-integrated answer is interesting is to keep things as 
> simple as possible for the user.  It should be click and go.  We already have 
> a simple answer for developers: launch netmeeting or a SIP softphone and give 
> it the IP address.  But this is horrible for users because in most cases it 
> won't even work due to firewalls.

Yup, you are right. Thanks to this Skype is so popular with "normal" 
(not technical) people. You only need to download file, install (next, 
next, finish), start application (probably it does it automatically), 
enter your own ID and start calling.
With IAX situation is little more complicated - you need to know your 
party IP address or use one of the free providers. In readme for JT or 
Psi there could be info what providers are available or selected one 
prefered for Psi users. I know that this isn't perfect solution, but 
full integration with Jabber needs something similar (like predefined 
GoogleTalk server(s)).
I chose IAX because it's easier to configure (than SIP) and it's 
firewall transparent.

> Johnny Talker sounds like it has a lot in common with an external application.  
> Have a look at iChat AV sometime to see how this type of integration turns 
> out.  iChat has a built-in SIP implementation that negotiates a voice/video 
> session between users.  Since it is built-in, the UI is clean.  However, 
> since it operates independently from the IM part, it is unfortunately about 
> as effective as an external application.  In other words, it never actually 
> works.
> 
> What can you say about these things?

I saw iChat only on screens (I don't have Mac), but every "stand-alone" 
VoIP application has similar problems.
If someone would be able to set up free IAX server (for example using 
Asterisk) dedicated for Jabber users (something like intergration with 
Jabber :) ) and it would be predefined in Psi it should be easier for 
"normal" users.

Regards
-- 
Marcin