Administrator Guide

Routing in and out of VXLAN tunnels

VXLAN provides a way to extend a VLAN over a Layer3 tunnel (VXLAN tunnel) across data centers.

This functionality can also be extended one step further by enabling routing from a VLAN on one data center to a different VLAN on

another data center. This scheme to route in and out of tunnels (RIOT) requires setting up of hardware VTEPs that are capable of routing

over a VXLAN tunnel using a physical loopback configuration.

Physical Loopback for VXLAN RIOT

The following topology shows how VXLAN RIOT can be achieved using physical loopbacks. Two port-channels, vxlan and non-vxlan

loopback port-channel, are created in the device. Interface connected at one end of the physical loopback cable is/are added as member

of the non-vxlan loopback port-channel (P2/P6) and other end interfaces as a member of vxlan loopback port-channel (P3/P7).

In this RIOT scheme, whenever R1 tries to reach R2, the packet gets to P1 on VTEP 1 with VLAN 10 and gets routed out of P2 on VLAN

20. VTEP 1 sends an ARP request for R2 (10.1.2.1) through P2. This request gets VXLAN encapsulated at P3 and is sent out of P4.

Eventually, the native ARP request reaches R2.

R2 sends an ARP response that is VXLAN encapsulated at VTEP 2. This response reaches VTEP 1 on P4 with a VXLAN encapsulation. At

this point, the ARP response is de-capsulated at P4. The native ARP response egresses through P3 and re-enters through P2. The ARP is

then resolved pointing to P2.

After this ARP discovery is complete, the existing routing and VXLAN encapsulation mechanisms facilitate routing over VXLAN tunnels

between R1 and R2.

NOTE: VXLAN feature is not supported in a stacking environment

Internal Loopback for VXLAN RIOT

The following topology shows how VXLAN RIOT can be achieved using an internal loopback port channel. Internal loopback port-channel

is formed by adding the free ports in the device as a member to the vxlan loopback port-channel. There is no need for non-vxlan loopback

port-channel in this scenario.

Virtual Extensible LAN (VXLAN)

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