Nova Networking Design Mode

Type	Strengths	Weaknesses
Flat	Extremely simple. No DHCP broadcasts.	Requires file injection into the instance. Limited to certain distributions of Linux. Difficult to configure and is not recommended.
FlatDHCP	Relatively simple to setup. Standard networking. Works with all operating systems.	Requires its own DHCP broadcast domain.
VlanManager	Each tenant is isolated to their own VLANs.	More complex to set up. Requires its own DHCP broadcast domain. Requires many VLANs to be trunked onto a single port. Standard VLAN number limitation. Switches must support 802.1q VLAN tagging.
FlatDHCP Multi-host HA	Networking failure is isolated to the VMs running on the hypervisor affected. DHCP traffic can be isolated within an individual host. Network traffic is distributed to the compute nodes.	More complex to set up. By default, compute nodes need public IP addresses. Options must be carefully configured for live migration to work with networking.