[Neutron] Multi segment networks
Hello guys, Quick question about multi-segment provider networks. Let's say I create a network and a subnet this way: neutron net-create multinet --segments type=dict list=true provider:physical_network='',provider:segmentation_id=1500,provider:network_type=vxlan provider:physical_network=physnet_sriov,provider:segmentation_id=2201,provider:network_typ e=vlan neutron subnet-create multinet --allocation-pool start=10.100.5.2,end=10.100.5.254 --name mn-subnet --dns-nameserver 8.8.8.8 10.100.5.0/24 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? Thanks in advance! -- Ricardo Noriega Senior Software Engineer - NFV Partner Engineer | Office of Technology | Red Hat irc: rnoriega @freenode
Hi Ricardo, On Thu, Feb 7, 2019 at 6:45 PM Ricardo Noriega De Soto <rnoriega@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-netw... [2] https://docs.openstack.org/neutron/latest/admin/config-routed-networks.html
participants (2)
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Bence Romsics
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Ricardo Noriega De Soto