A method and apparatus for link state determination in voice over frame-relay networks. In one embodiment, the present invention includes a method for determining link state for permanent calls in an FRF.11 voice over data network at the virtual voice channel level. This is a capability not present in...http://www.google.de/patents/US6657970?utm_source=gb-gplus-sharePatent US6657970 - Method and apparatus for link state determination in voice over frame-relay networks
