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<p style="margin-bottom: 0cm; margin-top: 0pt;">Oleg Goldshmidt wrote:<br>
</p>
<blockquote cite="mid:m3mybotitb.fsf@goldshmidt.org" type="cite"><br>
<pre wrap="">
</pre>
<blockquote type="cite">
<pre wrap="">It is, indeed, worth a try.
</pre>
</blockquote>
<pre wrap=""><!---->
If you do, I am curious whether it works or not, so a summary will be
appreciated.
</pre>
</blockquote>
Me it'll take some time until I get to try it. If Daniel tries it,
please do report.<br>
<blockquote cite="mid:m3mybotitb.fsf@goldshmidt.org" type="cite">
<pre wrap="">
</pre>
<blockquote type="cite">
<pre wrap="">Switching is fine, as long as they are only layer 2 aware. So long
as you actually have two actual physical network cards, there is no
reason for the packet not to go out. A layer 3 switch might notice
the short path, but a layer 2 switch should work fine.
</pre>
</blockquote>
<pre wrap=""><!---->
Unless VM0 sends an ARP inquiring about the destination IP,</pre>
</blockquote>
This ARP is sent to a physical NIC.<br>
<blockquote cite="mid:m3mybotitb.fsf@goldshmidt.org" type="cite">
<pre wrap=""> VM1
dutifully replies with its MAC (all through the hypervisor's virtual
switch),</pre>
</blockquote>
No, as far as the machine is concerned, the sending out of an ARP
through VM1 and receiving it through VM0 are two separate events.
Unless it is layer 3 aware, there is no reason for it to know that the
ARP received through a physical Ethernet device originated in our
machine.<br>
<blockquote cite="mid:m3mybotitb.fsf@goldshmidt.org" type="cite">
<pre wrap=""> then VM0 stack forms a frame with VM1's MAC as destination.
</pre>
</blockquote>
Of course it does. I find it hard to believe that a VM would form a
switch between two separate physical interfaces. In fact, VMs work
extra hard to make sure that you can INCREASE the number of physical
layers you have, no decrease it.<br>
<blockquote cite="mid:m3mybotitb.fsf@goldshmidt.org" type="cite">
<pre wrap="">The frame, from VM0's point of view, goes out of its *virtual* NIC,
and then gets L2-switched locally by the virtual switch without going
out of any physical interface.
</pre>
</blockquote>
Who gave the VM the right to assume that VM1 and VM0 are layer 2
connected? If it does that, switch VM software - it's a bug.<br>
<br>
Shachar<br>
<br>
<br>
<pre class="moz-signature" cols="72">--
Shachar Shemesh
Lingnu Open Source Consulting Ltd.
<a class="moz-txt-link-freetext" href="http://www.lingnu.com">http://www.lingnu.com</a>
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