In one embodiment, a method comprises a network device detecting an event severity encountered by the network device; the network device selectively changing a window size, for a maximum number of unacknowledged data packets that can be sent by the network device to a receiver device, to correspond to the event severity encountered by the network device; and the network device transmitting, to the receiver device, a number of data packets up to the window size, enabling the receiver device to detect the corresponding event severity encountered by the network device based on the number of unacknowledged data packets received by the receiver device from the network device.