Encapsulation overhead calculator Encapsulation overhead calculator Parent interface MTU: Calculation mode: PDU size (substract overhead from MTU) Frame size (add overhead to payload size) Overhead: Maximum PDU size: Protocols (click protocol buttons one or more time to add): Notes PDU (Protocol Data Unit) is a general term for frames, packets, segments etc. If you want to calculate tunnel MTU, specify protocols before the encapsulated one. That is, if you want MTU for GRE over IPv4, add IPv4 and GRE. PDU value will be your MTU, whatever you encapslate into GRE must not excee...