Centralized VXLAN IP gateway deployment


[NOTE: ]

NOTE:

Centralized VXLAN IP gateways support only IPv4 sites.


As shown in Figure 12, a VTEP acts as a gateway for VMs in the VXLANs. The VTEP both terminates the VXLANs and performs Layer 3 forwarding for the VMs.

Figure 12: Centralized VXLAN IP gateway placement design

As shown in Figure 13, the network uses the following process to forward Layer 3 traffic from VM 10.1.1.11 to the Layer 3 network:

  1. The VM sends an ARP request to obtain the MAC address of the gateway (VTEP 3) at 10.1.1.1.

  2. VTEP 1 floods the ARP request to all remote VTEPs.

  3. VTEP 3 de-encapsulates the ARP request, creates an ARP entry for the VM, and sends an ARP reply to the VM.

  4. VTEP 1 forwards the ARP reply to the VM.

  5. The VM learns the MAC address of the gateway, and sends the Layer 3 traffic to the gateway.

  6. VTEP 3 removes the VXLAN encapsulation and inner Ethernet header for the traffic, and forwards the traffic to the destination node.

Inter-VXLAN forwarding is the same as this process except for the last step. At the last step of inter-VLAN forwarding, the gateway replaces the source-VXLAN encapsulation with the destination-VXLAN encapsulation, and then forwards the traffic.

Figure 13: Example of centralized VXLAN IP gateway deployment