Cilium VXLAN

Concept Reference: VXLAN

When you install Cilium (or other CNIs like Flannel or Calico), by default, it usually uses VXLAN to create an overlay network.

It's the easiest way to make all pods communicate no matter which nodes they're in, because it doesn't need any configuration on the physical routers or switches. It just works in any network that allows UDP traffic. * Default Port: Cilium uses UDP port 8472 by default for VXLAN traffic.

In Cilium, two main datapath options exist: 1. Tunneling (Overlay): Uses VXLAN or Geneve. 2. Native Routing: Avoids the VXLAN overhead, but requires the underlying network to understand Pod IPs (often configured via BGP).