A message handler is described. The message handler is configured, in response to receiving a data package which is formatted according to a given communications protocol, such as CAN or Ethernet, and which comprises package-directing data and payload data, to generate package having a predetermined data format, for example a layer-2 or layer-3 package, which comprises a header and payload data. The header comprises an address generated in dependence upon the package-directing data and wherein the payload comprises the data package. The package having a predetermined data format may be an IEEE 1722 frame.