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From: Tim Epkes <tim.epkes@gmail.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] Qemu-KVM VETH
Date: Fri, 20 Sep 2013 16:03:14 -0400	[thread overview]
Message-ID: <F38411C9-5C6F-4724-950C-244ABA4DAD2B@gmail.com> (raw)
In-Reply-To: <20130920172626.GA14589@stefanha-thinkpad.redhat.com>

Agree in all points.  Thanks for the information.  I'll give the patch a try.

Tim

Sent from my iPhone

On Sep 20, 2013, at 1:26 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote:

> On Fri, Sep 20, 2013 at 11:48:50AM -0400, Tim Epkes wrote:
>> The problem aI face is that a bridge in the middle ( using taps) breaks
>> LLDP ( L2 discovery protocol) and should break ISIS as well.  Sockets
>> aren't bad, but if for some reason I take the listener VM down and bring
>> back up, then I have to bring down all connector VMs, which chains on
>> itself if there is a lot of connectivity defined.  When UDP was available
>> that wasn't an issue.
> 
> I just checked linux.git but this patch has not been applied (although
> it's trivial if you're willing to rebuild your kernel from source):
> http://comments.gmane.org/gmane.linux.network/208908
> 
> It sounds like improving net/socket.c might be the right place to look.
> 
>> Anyway, that is how I came to VETHs.  I am aware that you can use UDP
>> multicast, but performance past one hop is extremely poor ( resulting in 3
>> of 5 pings to be lost.  Thanks
> 
> Unfortunately the veth driver does not hand Ethernet frames to/from
> userspace.  We really need something tap-like where userspace can
> inject/extract packets.
> 
> Stefan

  reply	other threads:[~2013-09-20 20:03 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-19 21:31 [Qemu-devel] Qemu-KVM VETH Tim Epkes
2013-09-20 11:58 ` Stefan Hajnoczi
2013-09-20 15:48   ` Tim Epkes
2013-09-20 17:26     ` Stefan Hajnoczi
2013-09-20 20:03       ` Tim Epkes [this message]
2013-09-24 19:55       ` Tim Epkes
2013-09-25  8:10         ` Stefan Hajnoczi
2013-09-25 11:35           ` Tim Epkes

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