Some communications between devices are limited by network boundaries for ensuring security. In these cases, IEEE1888 does not provide inter-device communication. We thus propose IEEE1888 over WebSocket for communication between devices across network boundaries. In IEEE1888 over WebSocket, two devices are added to an IEEE1888 network for communication across network boundaries, so devices using traditional IEEE1888 need not to be changed. We implemented an experimental system of IEEE1888 overWebSocket. The results shows that IEEE1888 over WebSocket enables communication across network boundaries.