Open Stack

Hi Ricardo,

On Thu, Feb 7, 2019 at 6:45 PM Ricardo Noriega De Soto
<rnoriega at redhat.com> wrote:
> Does it mean, that placing two VMs (with regular virtio interfaces), one in the vxlan segment and one on the vlan segment, would be able to ping each other without the need of a router?
> Or would it require an external router that belongs to the owner of the infrastructure?

To my limited understanding of multi-segment networks I think neutron
generally does not take care of packet forwarding between the
segments. So I expect your example net-create command to create a
network with two disconnected segments.

IIRC the first time when multi-segment networks were allowed in the
API, there was no implementation of connecting the segments at all
automatically. The API was merged to allow later features like the
routed-networks feature of neutron [1][2].

Or to allow connecting segments administratively outside of neutron
control. I'm not sure if it is well defined how the segments should be
connected - on l2 or l3. I think people originally thought of mostly
bridging the segments together. Then the routed networks feature went
to connect them by routers. I guess it depends on your use case.

Hope this helps,
Bence Romsics (rubasov)

[1] https://specs.openstack.org/openstack/neutron-specs/specs/newton/routed-networks.html
[2] https://docs.openstack.org/neutron/latest/admin/config-routed-networks.html