What is VXLAN (Virtual Extensible LAN)?

VXLAN is a technology that tunnels Layer 2 frames over a Layer 3 connection. It achieves this by encapsulating received frames in a UDP packet before sending them across the network. This allows network administrators to place devices on separate physical networks within the same Layer 2 virtual network. In essence, it acts like VLANs but runs over a Layer 3 distribution layer.

The problem

VXLAN is useful for any scenario requiring distant devices to reside in the same virtual network. This is highly practical in large datacenter environments where several VMs often need to be on the same subnet but may be located in different racks or buildings. Additionally, VXLAN is frequently used in wireless systems for roaming; it allows a wireless client to maintain its original IP address no matter where it roams across a physical campus.

At UCCS, I implemented a system combining VXLAN and WireGuard to build an ad-hoc bridge that added non-wireless devices to the Wi-Fi network infrastructure.

The issue with VXLAN is that it can massively overcomplicate a network while adding little value. The complexity and performance overhead of VXLAN are often significant during larger deployments, making the benefits rare compared to traditional methods. VLANs and standard routing are almost always better options since they are easier to troubleshoot and have significantly less overhead. While it is tempting to adopt the latest technology, sometimes simpler is better.