Re: [Qemu-devel] [PATCH] add a command line option to specify the interface to send multicast packets on

[Stefan Weil]

Am 15.11.2010 22:07, schrieb Anthony Liguori:
> On 11/15/2010 01:52 PM, Mike Ryan wrote:
> > I'll clarify/elaborate a bit:
> >
> > When using a multicast socket, the OS chooses a default physical
> > interface to send packets. The patch I've supplied allows the user to
> > select the interface.
> >
> > Suppose you have a setup like so:
> >
> > BoxA --- BoxB --- BoxC
> >
> > You wish to run virtual machines on BoxB and BoxC and network them using
> > a multicast UDP socket.
> >
> > BoxB has two network interfaces, and the default multicast interface may
> > be the link between BoxA and BoxB. In this situation, BoxC will not
> > receive any multicast packets from BoxB and networking between the boxes
> > is therefore impossible.
> >
> > The utility of a multicast socket is obviously limited in my simplified
> > example. Generalize BoxC to a LAN of physical machines all running
> > virtual machines you wish to network and the use case should become a
> > bit clearer.
>
> Thanks.  Second question is how portable is SIOCGIFADDR?  I suspect 
> that's very Linux-centric..
>
> Regards,
>
> Anthony Liguori


Yes. It is unavailable for mingw32 (windows).

Regards,

Stefan Weil