VLAN is on the radar, vxlan/gre was done to start with. I believe Vivek mentioned the rationale in some other thread. The gist of it below:
In the current architecture, we use a unique DVR MAC per compute node to forward DVR Routed traffic directly to destination compute node. The DVR routed traffic from the source compute node will carry 'destination VMs underlay VLAN' in the frame, but the Source Mac in that same frame will be the DVR Unique MAC. So, same DVR Unique Mac is used for potentially a number of overlay network VMs that would exist on that same source compute node. The underlay infrastructure switches will see the same DVR Unique MAC being associated with different VLANs on incoming frames, and so this would result in VLAN Thrashing on the switches in the physical cloud infrastructure. Since tunneling protocols carry the entire DVR routed inner frames as tunnel payloads, there is no thrashing effect on underlay switches. There will still be thrashing effect on endpoints on CNs themselves, when they try to learn that association between inner frame source MAC and the TEP port on which the tunneled frame is received. But that we have addressed in L2 Agent by having a 'DVR Learning Blocker' table, which ensures that learning for DVR routed packets alone is side-stepped. As a result, VLAN was not promoted as a supported underlay for the initial DVR architecture. Cheers, Armando On 16 September 2014 20:35, 龚永生 <[email protected]> wrote: > I think the VLAN should also be supported later. The tunnel should not be > the prerequisite for the DVR feature. > > > ------------------ Original ------------------ > From: "Steve Wormley"<[email protected]>; > Date: Wed, Sep 17, 2014 10:29 AM > To: "openstack-dev"<[email protected]>; > Subject: [openstack-dev] [neutron] DVR Tunnel Design Question > > In our environment using VXLAN/GRE would make it difficult to keep some of > the features we currently offer our customers. So for a while now I've been > looking at the DVR code, blueprints and Google drive docs and other than it > being the way the code was written I can't find anything indicating why a > Tunnel/Overlay network is required for DVR or what problem it was solving. > > Basically I'm just trying to see if I missed anything as I look into doing a > VLAN/OVS implementation. > > Thanks, > -Steve Wormley > > > _______________________________________________ > OpenStack-dev mailing list > [email protected] > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
