A method and system for maintaining quality of service parameters for transmissions as a native Ethernet service between a first network having a first communication protocol and a second network having a second communication protocol. The interworking device includes a first network interface operable to communicate with the first communication network using the first communication protocol, a second network interface operable to communicate with the second communication network using second communication protocol and a processing unit in communication with the first network interface and the second network interface. The processing unit receives a frame from the first network in the first communication protocol, maps parameters corresponding to quality of service parameters in the first communication protocol to quality of service parameters in the second communication protocol and assembles a data packet in the second communication protocol. The assembled data packet includes mapped quality of service parameters.