Forwarding Model Defined in NVO3

Elements in the NVO3 Forwarding Model

nVirtual Access Point (VAP): The tenant system connects to virtual networks (VNs) through VAPs. A VAP can be a physical port, a VLAN, or an interface of a vSwitch.

nVirtual Network Instance (VNI): VNI here refers to a VN instance in the NVO3 framework but not the VXLAN network identifier.

nVN Context: field identifying a VN in overlay encapsulation, similar to the VNI in the VXLAN header and VSI in NVGRE. Overlay Module: implements encapsulation and decapsulation on the overlay network

NVO3 forwarding procedure

n1. A tenant packet is sent to a virtual network through a VAP.

n2. The NVE searches the MAC table at Layer 2 or routing table at Layer 3 according to the forwarding rule in the VNI.

n3. The NVE adds VN Context to the packet and sends the packet to the remote device.

n4. The overlay module implements tunnel encapsulation.

n5. The packet is transparently transmitted through the overlay network.

n6. The overlay module of the egress NVE decapsulates the packet.

n7. The packet is mapped to the local VNI based on the VN Context.

n8. The egress NVE searches the MAC table at Layer 2 or routing table at Layer 3 according to the forwarding rule in the VNI.

n9. The packet is forwarded to the local tenant system through a VAP based on the search result.

NVE Node Discovery and Tunnel Establishment

NVE Node Discovery

nThe VXLAN standard does not define an NVE node discovery protocol.

nCurrently, NVE nodes associated with virtual networks can be discovered by running commands or configuration on a controller.

Tunnel Establishment

nThe VXLAN standard does not define a tunnel establishment protocol.

nCurrently, the VXLAN tunnel is set up between devices by running commands or configuration on a controller. 

nSome competitors can set up VXLAN tunnels dynamically in multicast mode.