J1939/81 specifies the network management for a J1939 network and is the only network management layer published and supported for J1939. This specification is concerned with the management of source addresses and the association of those addresses with an actual function and with the detection and reporting of network related errors.

Due to the nature of management of source addresses, J1939-81 also specifies initialization processes, requirements for reaction to brief power outages and minimum requirements for ECUs on the network.