A network access device is described that uses a modified lower layer two (L2) software interface that is enhanced to operate as a proxy for a dynamic upper L2 software interface when the upper L2 software interface has been torn down, i.e., terminated unbeknownst to a subscriber device. The lower L2 software interface may, for example, be extended to incorporate certain features of the upper L2 software interface to detect such a condition. In the absence of the upper L2 software interface, the lower L2 interface may output a simulated termination request on behalf of the upper L2 interface and in accordance with the upper L2 protocol.