Combinations of Underlay and Overlay Networks

A basic network on which a VXLAN tunnel is established is called an underlay network, whereas the service network carried by the VXLAN tunnel is called an overlay network. In VXLAN scenarios, the following combinations of underlay and overlay networks are applicable. Therefore, S series switches configured with VXLAN support the following combinations of underlay and overlay networks.

Category	Definition	Example
IPv4 over IPv4	The overlay network and underlay network are both IPv4 networks.	As shown in Figure 1, the Host IP and VTEP IP addresses are all IPv4 addresses.
IPv6 over IPv4	The overlay network is an IPv6 network, and the underlay network is an IPv4 network.	As shown in Figure 1, the Host IP addresses are IPv6 addresses, and the VTEP IP addresses are IPv4 addresses.
IPv4 over IPv6	The overlay network is an IPv4 network, and the underlay network is an IPv6 network.	As shown in Figure 1, the Host IP addresses are IPv4 addresses, and the VTEP IP addresses are IPv6 addresses.
IPv6 over IPv6	The overlay network and underlay network are both IPv6 networks.	As shown in Figure 1, the Host IP and VTEP IP addresses are all IPv6 addresses.

Only the S6730-S, S6730S-S, S5732-H, S5731-S, S5731S-S, S5731S-H, S5730-HI, S6730-H, S6730S-H, S5731-H, and S6720-HI support IPv6 network-based VXLAN configuration.

Figure 1 Combinations of underlay and overlay networks

VXLAN implementation principles are similar in the preceding combinations of underlay and overlay networks. To make the description concise and clear, an IPv4 over IPv4 network is taken as an example for subsequent descriptions. For other types of network combination, only the implementation differences are described.