Re: [Qemu-devel] net: RFC New Socket-Based, Switched Network Backend (QDES)

[Mike Lovell]

On 06/25/2012 04:40 AM, Stefan Hajnoczi wrote:
> On Mon, Jun 25, 2012 at 6:42 AM, Mike Lovell<address@hidden>  wrote:
> > This is what I've been calling QDES or QEMU Distributed Ethernet Switch. I
> > first had the idea when I was playing with the udp and mcast socket network
> > backends while exploring how to build a VM infrastructure. I liked the idea of
> > using the sockets backends cause it doesn't require escalated permissions to
> > configure and run as well as the ability to talk over IP networks.
> >
> > But the built in socket backends either allowed for only 2 guests talking
> > directly or for multiple guests where all traffic is sent to all. So one can
> > either have two guests talking or have bandwidth wasted with multiple guests.
> > There wasn't something that could talk to multiple guests but also utilize
> > unicast traffic.
> Have you looked at QEMU's net/vde.c backend?
>
> Does VDE (http://vde.sourceforge.net/) already do everything that QDES does?
>
> Stefan

I have looked at VDE and used it for a few things. I think QDES has an 
advantage over VDE in that it doesn't require additional steps to get up 
and running. With VDE, one has to at least start a vde_switch process on 
the host for the guest to connect to. Then, if multiple hosts are being 
used, the multiple vde_switch processes have to be connected. Maybe 
through some vde_plug processes connected through netcat or ssh. Its a 
few extra steps that can be a pain in a dynamic environment. With QDES, 
the only configuration should be the options to QEMU as long as the 
multiple hosts can send and receive data through the same multicast 
address.

QDES doesn't have anywhere close to the feature set that VDE does. This 
doesn't do VLANs at the switching level. It doesn't support STP so 
connecting it to other bridges might cause weird behavior. Etc. But it 
does provide a really easy way for multiple guests on multiple hosts to 
be connected.

mike