Re: [Qemu-devel] Connecting two tap interfaces to one qemu instance

[Jedrzej Kalinowski <kalinoj1@iem.pw.edu.pl>]

Brian Jackson pisze:
> Try turning STP on for the bridge maybe.
> 
> 
> On May 28, 2009, at 3:23 PM, Jedrzej Kalinowski wrote:
> 
>> Hello,
>>
>> I've found a problem when trying to run one qemu instance with two tap
>> devices connected to a bridge.
>>
>> I mean a commandline like this:
>> qemu -net nic -net tap -net nic -net tap ...
>>
>> After a short time (in seconds, rather than minutes, depends on the
>> machine I'm runnig qemu) my network gets flooded with packets - mostly
>> arp requests gathered from all over the network and replicated.
>>
>> What's interesting there is no problem with running two or more qemu
>> instances, when giving each one a tap device and connecting all of them
>> to the same bridge - everything works fine then.
>>
>> The issue appears on qemu 0.10.5 stable both in FreeBSD and Linux
>> environment.
>>
>> Have any of you tried to use two tap devices in one qemu instance? Any
>> luck?
>>
>>
>>
>> Any information would be greatly appreciated,
>> Jedrzej Kalinowski
>>
>>
> 

Yes, I tried STP on bridge and it helps.
But it's fighting effects, not cause of the problem

My understanding is that qemu should not work like this. Usual host with
two network devices connected to the same network doesn't create loops
like this.

--
Jedrzej Kalinowski