[LINK] Alternatives to Skype

[Fernando Cassia]

On Fri, Feb 15, 2013 at 10:10 PM, Kim Holburn <kim.holburn at gmail.com> wrote:
> The problem with alternatives to skype is that skype has a way of getting through firewalls by using random external servers/machines.    The main problem faced by any P2P (in the classical sense) is with domestic NAT routers.  VOIP standards are particularly broken, we've discussed this before on link.

http://code.google.com/p/ice4j/

"The Interactive Connectivity Establishment (ICE) protocol combines
various NAT traversal utilities such as the STUN and TURN protocols in
order to offer a powerful mechanism that allows Offer/Answer based
protocols such as SIP and XMPP to traverse NATs"

http://en.wikipedia.org/wiki/Jitsi

"Among others Jitsi uses the JAIN-SIP protocol stack for SIP support
and the Jive Software Smack library [9] for XMPP.[10]

The fact that Jitsi properly handles IPv6 is especially interesting
for direct PC-to-PC (peer-to-peer) communication, for instance, if
both sides are 'trapped' behind NAT routers, but obtain a reachable
IPv6 address via a tunnel-broker.

The Jitsi community has also completed an ICE implementation called
ice4j.org, which it uses to provide NAT traversal capabilities, and
assist IPv4 to IPv6 transition.[11]"

Regards,
FC