Introduction to Virtual Extensible LAN (VXLAN)

Lessons Discussion
51

Hello Ediekes

Using the same VLAN ID with different VNIs is a common practice in large deployments where you want to provide L2 connectivity across different VXLAN segments.

To demonstrate how this is done, I’ll provide a basic example using Cisco Nexus switches, which are commonly used in data centers and support VXLAN configurations. However, keep in mind that the exact commands might vary depending on the platform and software version. This is a simplified configuration, and a production environment might have additional requirements.

  1. Configuring the NVE interface (this is the VXLAN tunnel interface):
interface nve1
  no shutdown
  source-interface loopback0
  member vni 123
    mcast-group 239.1.1.1
  member vni 321
    mcast-group 239.1.1.2
  1. Mapping VLAN to VNI:

For VNI 123:

vlan 456
  vn-segment 123

For VNI 321 (on another segment or even on the same switch if it’s serving multiple VXLAN segments):

vlan 456
  vn-segment 321
  1. Configure the physical interfaces as needed:
    For example, if you’re trunking this VLAN:
interface Ethernet1/1
  switchport mode trunk
  switchport trunk allowed vlan 456

Note that:

  • The multicast groups (mcast-group) configured in the example above represent the multicast group IP addresses used for multicast traffic handling in VXLAN. The IPs are just placeholders and should be replaced by actual multicast IPs suitable for the network.
  • You must also ensure proper IP routing between VTEP devices.
  • The actual configuration might vary depending on specific requirements, other features in use, and the exact hardware/software version.

For some more info on how to configure VXLAN, take a look at the folloing lesson:

I hope this has been helpful!

Laz