[PlanetCCRMA] data over local network

[Paul Coccoli]

On Mon, May 10, 2010 at 11:36 AM, David Nielson <naptastic at comcast.net> wrote:
>
> On 05/10/2010 09:00 AM, Oded Ben-Tal wrote:
> > hi,
> > thanks for the reply and appologies for being a bit slow. But how do I
> > assign the ip addresses? We are connecting via a hub (not router) and the
> > mac (and my laptop under windows) gets an ip address somehow from the hub
> > with the first 2 numbers shared - i.e. mac had 169.256.x.y win had
> > 169.256.z.q
> > I think once I get to the successful ping stage we should be fine - we
> > managed to get OSC messages across with udpsend/receive between max and
> > pd.
> >
> > thanks
> > Oded
> >
> The addresses which start with 169.256 are not real IP
> addresses--Windows and OS X generate them internally and then flip an
> internal switch that says "don't even try to connect to the outside
> world." Getting OSC through under these circumstances is impressive; you
> shouldn't have been able to.

I assume the OP meant 169.254, not 256.  The 169.254 block is
link-local, hence 2 machine connected to hub using such addresses will
communicate just fine.  In fact, that's why it worked with the Mac and
Windows boxes.  After failing to get a DHCP lease, both apparently
fell back to link-local addresses and everything was fine.  Many linux
systems don't follow this behavior, which I think is a property of the
DHCP client software.

> You will need to either (a) assign static IP addresses, which you can do
> using NetworkManager on Linux and I don't know how to do it on OS X, or
> (b) have a third computer in your network that acts as a DHCP server and
> assigns IP addresses in a sane way.

You could just pick a 169.254 address different from the other guy's.
You may also need to add a route to the network, such as "ip route add
169.254.0.0/16 dev eth0".

> When you say "hub," do you mean "hub" or "switching hub" or "switch"?
> (The last two are basically the same thing.)
>
> If you're going to be sending data back and forth over a network, you
> really will need to understand networking better. Don't take this as an
> RTFM even though that's basically what I'm saying, but get on Wikipedia
> at least and read these articles plus whatever else you need to read
> until you understand more fully what's going on with your network:
>
> http://en.wikipedia.org/wiki/OSI_model
> http://en.wikipedia.org/wiki/Internet_Protocol_Suite
> http://en.wikipedia.org/wiki/IP_address
> http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol
> http://en.wikipedia.org/wiki/Open_Sound_Control
>
> Good luck!
>
> David
>
> _______________________________________________
> PlanetCCRMA mailing list
> PlanetCCRMA at ccrma.stanford.edu
> http://ccrma-mail.stanford.edu/mailman/listinfo/planetccrma