Good dialogue. This approach makes sense as it fosters an ecosystem of commercial and open source routing providers layering on top of OVS as a platform -- Rather than the OVS project taking up the task of deciding what people want and developing a suite of routing protocols from scratch.
Cheers, Brad On Tue, Nov 20, 2012 at 8:21 AM, Will Dennis <[email protected]>wrote: > Thanks, Ben, for your response. This clears things up for me. The routing > function must be provided by an outside means, whether an OF controller, or > a host-based or perhaps external router (trunk connection to external > router, what is called "router-on-a-stick" in some circles.) I was just > trying to determine if OVS itself had a routing function "built-in" (static > or perhaps even dynamic) that I was missing. > > Best, > Will > > > On Nov 19, 2012, at 11:47 PM, Ben Pfaff <[email protected]> wrote: > > > On Mon, Nov 19, 2012 at 10:21:50PM -0500, Willard Dennis wrote: > >> 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.netfor > >> 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.) > > > > I'm not sure what the exact intent of that claim is. It may simply mean > > that Open vSwitch can match and act based on multiple layers > > (specifically, L2, L3, and L4). But I believe that it is still correct, > > even if one takes the narrower meaning that you suggest, because there > > are at least two ways that you can implement routing with OVS. One is > > to use OpenFlow, with a controller. Another is to use the Linux TCP/IP > > stack, on the same box running Open vSwitch, possibly with network > > namespaces to implement separation. > _______________________________________________ > discuss mailing list > [email protected] > http://openvswitch.org/mailman/listinfo/discuss >
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