Can we create only 4094 networks using OVS?
On creating a network each tap interfaces at the br-int are associated to each vlan on OVS. It indicates that there are one-to-one mappings between VLAN IDs and GRE/VXLAN tunnel IDs.
In detail, When i create a network, a tap interface is created in br-int with a VLAN associated to it in the neutron node. So if i create 100 networks, then 100 tap interfaces will be created with 100 vlan-id's associated with each other. If this is the way it works, then Can we create only 4096 networks,since on creating 4097th network, the VLAN may be exhausted?
Please reply what will happen specific to neutron node? because this wont be a issue at compute node.
If tenant_network_types = vxlan ( or gre ) , then tap-interface created at br-int doesn't get VLAN ID which uniquely identifies your private subnet. There is no one-to-one mappings between VLAN IDs and GRE/VXLAN tunnel IDs.
VLAN is not unique across hosts,since vlan has limitation of 4096 you can have only that many networks in each node.You will hit other limitations before reaching 4096 networks.Also VLAN just need to be unique per hosts.Its not send through tunnels.I have a detailed answer but its awaiting approval
Why its not an issue at compute node??It will be an issue.As mentioned in a real production environment you will hit other limits before hitting VLAN limit of 4096