A method of adjusting fields of a datagram in the handling of the datagram in a network device may comprising receiving a datagram, with the datagram having at least module identifier fields and port identifier fields, at a port of a network device, adding or subtracting an offset value to at least one of the module identifier fields and at least one of the port identifier fields of the datagram based on data registers in the network device, and forwarding the datagram to a legacy device based on the module and port identifier fields of the datagram. A size of each of the module identifier fields and the port identifier fields handled by the legacy device may be smaller than a size of the module identifier fields and port identifier fields handled by the network device.