[asterisk-users] OpenVPN on phones?

[Steve Totaro]

On Fri, Feb 5, 2010 at 1:46 AM, Dave Platt <dplatt at radagast.org> wrote:
>> Anyway - is there someone out there that know the behaviour of OpenVPN in regards of retransmits and such? A VPN that retransmits will at some point hurt you if you transmit media over it, especially if you scale it up.
>
> OpenVPN is well-behaved in that way.  It uses SSL over TCP for its
> "administrative" communications between peers - authentication
> and key exchange and other protocol negotiations.
>
> The VPN traffic itself - the payload - isn't sent over TCP.
> Instead, the incoming packets are tagged, encrypted, and
> transmitted via UDP, on the usual best-efforts basis.  OpenVPN
> will not, itself, retransmit those payload packets.  It's
> up to the endpoint protocols to do so, if they so choose.
>
> I've had quite good luck carrying SIP traffic over OpenVPN...
> used it between a hotel in Norway, and my home in California,
> a couple of weeks ago,  Even with the hotel end of the
> connection being over WiFi, I didn't notice any significant
> packet loss problems.

I have had great luck using SIP over OpenVPN and multiple VSAT hops
all over the world, the latency takes getting used to and there is
some packet loss, seems GSM works better than G729 on lower bandwidth
VSAT links, guess it has to do with lossy codecs and general packet
loss over VSAT.

Thanks,
Steve T