Configuring virtual overlay networks

A virtual overlay network uses tunneling protocols to extend isolated network segments between servers for multi-tenant data center networks. Overlay networking can be implemented using various networking protocols and standards. FortiADC supports the Virtual Extensive LAN (VXLAN) and Network Virtualization using Generic Routing Encapsulation (NVGRE) protocols.

VXLAN and NVGRE are officially documented in RFC 7348 and RFC 7637, respectively.

To configure a virtual overlay network:

1. From a virtual domain, go to Network > Interface.
2. Click the Overlay Tunnel tab.
3. Click Create New to display the configuration editor.
4. Configure the following Overlay Tunnel settings:
   

   Setting	Guideline
   Name	Specify a unique name for the overlay tunnel. Specify a unique name for the overlay tunnel. Valid characters are A-Z, a-z, 0-9, _, and -. No spaces. After you initially save the configuration, you cannot edit the name.
   Mode	Select a virtual overlay networking protocol: VXLAN NVGRE VXLAN is the default option.
   VXLAN Type	The VXLAN Type option is available if the Mode is VXLAN. Select the VXLAN gateway type: Linux VXLAN Flannel VXLAN Linux VXLAN is the default option.
   Interface	Specify the outing interface for VXLAN encapsulated traffic.
   IP Version	Select an IPv4 address type: IPv4 Unicast IPv4 Multicast
   Multicast TTL	The Multicast TTL option is available if the IP Version is IPv4 Multicast. Specify the multicast TTL. Valid values are from 0 (default) to 255, minimum value is 1.
   Destination IP	Specify the destination IP address. Note: For IPv4 unicast, you specify multiple IP addresses; for IPv4 multicast, specify one IP address only.
   Port	The Port option is available if the Mode is VXLAN. Specify the VXLAN destination port (number). The default is 4789. The valid range is 1–6553.
   VNI	The VNI option is available if the Mode is VXLAN. Specify the VXLAN network ID. The valid range is 1–16777215.
   VSID	The VSID option is available if the Mode is NVGRE. Specify the Virtual Subnet Identifier (VSID) for NVGRE.

5. Click Save.
   Once the Overlay Tunnel settings are saved, the Remote Host MAC Mapping will be available to configure.
6. In the Remote Host MAC Mapping section, click Create New to display the configuration editor.
7. Configure the following Remote Host MAC Mapping settings:
   

   Setting	Guideline
   Host MAC	Specify the MAC address of the remote host.
   VTEP	Specify the IPv4 address of the virtual tunnel endpoint.

8. Click Save.
   The dialog closes once the Remote Host MAC Mapping configuration is saved.
9. Click Save to update the Overlay Tunnel configuration.

Virtual overlay networking is supported on all FortiADC hardware platforms. For both VXLAN and NVGRE, the mapping can be configured either manually or dynamically (the system learns from the remote VTEP). For VXLAN, IPv4 multicast and IPv4 unicast IP addresses can be used as the destination IP of the VTEP. For NVGRE, only IPv4 unicast IP addresses can be used as the destination IP of the VTEP. Once an overlay tunnel is created, an interface with the same name as the tunnel name will be created automatically. It can be used to encapsulate or decapsulate VXLAN or NVGRE packets.