Re: [Jack-Devel] Problems with Networking Jack

On Tue, Aug 27, 2013 at 02:14:23PM +0100, David Woodfall wrote:
> On (27/08/13 12:04), David Woodfall <[hidden]> put forth the proposition:
> >Hi, I had until yesterday a working jack setup between my laptop and
> >server using netone. While trying to troubleshoot why the audio
> >was so out of sync while playing videos in mplayer, I tried playing
> >with my iptables firewall script. (The sync problem seemed to have
> >started when I connected a new router.)
> >
> >Well, I don't know exactly how I've done it but now I get no networked
> >sound at all unless I stop the master firewall completely.
> >
> >I'm guessing that I took out a line allowing access to a certain port.
> >Google doesn't help much except that I've found that UDP 3000 and UDP
> >on 19000 may be involved but allowing those hasn't helped. I also
> >tried playing with ICMP echo settings, but also to no avail.
> >
> >So my question is, what ports should be set on the master firewall to
UDP/19000. At the same time you need to make sure you're allowing local
musticats to get out of your firewall to your broadcast segment. Or you
need to use unicast peering instead of default multicast discovery.
> >fix this problem? I tried looking at netstat but only found some
> >random ports in use, which isn't very helpful.
> >
> >Incidentally, I also tried using -d net instead of -d netone, but then
> >I get no sound at all, even with firewalls on both machines off.
> 
> Well I solved the netone problem by specifying a -r port with
> jack_netsource.
> 
> I'd still like to know why using -d net doesn't work for me though.
>
First you need to understand the difference between netjack and netone.

From jackdmp perspective netjack(2) is Jack2 networking stack, while 
netone is jack(1) networking. Protocols are pretty different, as well as
daemons themselves.

Then the difference between master and slave.

Master is the one how has access to hardware and listens (passively)
for slaves to connect while genrating beacons for them to discover itself.

You can think of it as who is the clocking master - master is its own master
(having clocks from underlying hardware) and slave is using master clocks.
But slave is actively performing attempts to connect to the master (it is 
active from network perspective - initates connection).

So when you say -d net - you're creating network slave - i.e. jack2 daemon
who is expecting to connect to the master and be driven by that.
Network slave  - unless instructed to use unicast master - is waiting for
master's beacons on the BMA network to initiate connections. Once it
discovers master's beacon - it connects to it and becomes a part of the loop

Regards,
Ruslan

1377639130.28717_0.ltw:2, <20130827213147.GA31231 at ruff dot mobi>