Network electric device

A computer readable storage device, storing a protocol data unit for use by a network electric device to communicate with other network devices, the protocol comprising:

• an application layer,
• a network layer,
• a data link layer, and
• a physical layer,
• wherein the physical layer further comprises a special protocol for providing an interface with a dependent transmission medium, and the network layer further comprises a home code control sub-layer for managing a home code for network security when accessing the dependent transmission medium,
• wherein an application layer protocol data unit (APDU) is transmitted between the application layer and the network layer, a network layer protocol data unit (NPDU) is transmitted between the network layer and the data link layer and between the network layer and the home code control sub-layer, a home code control sub-layer protocol data unit (HCNPDU) is transmitted between the home code control sub-layer and the data link layer, and a data frame unit is transmitted between the data link layer and the physical layer,
• wherein the NPDU comprises an NPDU header, the APDU and an NPDU trailer,
• wherein the NPDU header comprises a start of packet (SLP) field, a destination address (DA) field, a sender address (SA) field, a packet length (PL) field and a network layer control (NLC) field,
• wherein the NLC field comprises a service priority (SP) field, an NPDU header length (NHL) field, a protocol version (PV) field, a network layer packet type (NPT) field, a transmission counter (TC) field and a packet number (PN) field, and
• wherein the NPT field is set as a first code for a request packet, a second code for a successful response packet, a third code for a failed response packet, a fourth code for a notification packet, and a fifth code for an interface with the home code control sub-layer.