Hello all,

On the OVS homepage, under the heading "What is Open vSwitch?" it states:
"Open vSwitch is a production quality, multilayer virtual switch [...]"

My understanding of a multilayer switch is one that not only does
traditional layer two switching, possibly with multiple VLANs (i.e
maintains separate L2 forwarding tables for each VLAN) but that also can do
routing between such VLANs (via virtual VLAN interfaces) without requiring
an outboard router.

In a testbed setup (comprised of a single Ubuntu Linux box) that I recently
constructed to learn more about Open vSwitch (and OpenFlow, though that is
ancillary to this discussion) I instantiated a OVS soft-switch that has
three VLANs on it:
VLAN 10 - actual physical ports (interfaces = eth0, eth1, etc.), used to
communicate with physical infrastructure
VLAN 20 - VM hosts (interfaces = vnet0, vnet1, etc - in this case, I'm
using KVM with libvirt)
VLAN 30 - connection to a router virtualization platform
(Dynamips/Dynagen/GNS3) via a tuntap interface [see http://www.gns3.net for
more detail if desired]

In looking into how to then configure routing between the three VLANs
within OVS, and not finding anything on the OVS site, I finally came upon
this article:
http://blog.scottlowe.org/2010/04/23/configuring-inter-vlan-routing/

So, it seems that the (current) OVS switch implementation is not what I'd
think of as a "multilayer" switch, as it seems that you have to use the
Linux kernel routing to perform the routing between the "vlanX" interfaces
(and this would be an "outboard" router to OVS to me.)

Am I confused as to the nature of "multilayer" in the OVS context? And, is
it true that routing between VLANs (at least at this point) be handled by
an "outboard" router, or can OVS handle inter-VLAN routing "natively"
somehow? Please do not interpret this as any sort of a "slam" on OVS, it's
amazing software and quite useful to me just as it is... Just trying to
understand.

Thanks for reading and responding...
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