Work out Geneve encapsulation bytes, the resulting inner MTU and the goodput lost to option TLVs.
Geneve is VXLAN's extensible cousin: the same 50-byte IPv4 floor, plus a variable options block that pushes real deployments to 66–74 bytes. Every option byte is taken straight out of the inner MTU, and goodput is the ratio of payload to total frame. Geneve is the encapsulation behind NSX and many cloud overlays, and an inner MTU set from the 50-byte VXLAN figure silently black-holes large flows once options are switched on.
Geneve Overhead
Geneve overhead = 14 (Ethernet) + 20 or 40 (outer IP) + 8 (UDP) + 8 (Geneve base) + option TLVs; inner MTU = path MTU − overhead.
Geneve overhead = 14 (Ethernet) + 20 or 40 (outer IP) + 8 (UDP) + 8 (Geneve base) + option TLVs; inner MTU = path MTU − overhead. Geneve is VXLAN's extensible cousin: the same 50-byte IPv4 floor, plus a variable options block that pushes real deployments to 66–74 bytes. Every option byte is taken straight out of the inner MTU, and goodput is the ratio of payload to total frame.
Geneve is the encapsulation behind NSX and many cloud overlays, and an inner MTU set from the 50-byte VXLAN figure silently black-holes large flows once options are switched on.
This calculator takes 5 inputs: Inner payload MTU, Underlay path MTU, Geneve option TLV bytes, Outer IP version, Underlay link rate. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.