Abstract: A surgical instrument is disclosed herein. The surgical instrument can include an end effector that includes jaws configured to transition between an opened condition and a closed condition, a plurality of electrodes positioned within the jaws of the end effector, a control circuit, and a memory configured to store an algorithm configured to cause the control circuit to determine an impedance signal based on signals received from the plurality of electrodes, detect a media positioned between the jaws of the end effector based on the determined impedance signal, determine a position of the detected media based on the received signals, and generate an alert associated with the detected media and the determined position.

Abstract: A technique that enables a source endpoint of a tunnel employing encapsulation to determine if a destination endpoint of the tunnel is reachable or unreachable. The technique issues “keepalive” packets that are returned to the source endpoint by a reachable destination endpoint. The source endpoint of the tunnel constructs a keepalive packet containing a return-keepalive packet, encapsulates it and forwards it over the tunnel to the destination endpoint. The destination endpoint, in turn, decapsulates the packet to yield the return-keepalive packet and forwards the return-keepalive packet preferably over the tunnel towards the source endpoint. Upon arrival at the source endpoint, the return-keepalive packet is processed. By receiving the return-keepalive packets the source end-point concludes the destination endpoint is reachable. After a predetermined number of return-keepalive packets have not been received, the source endpoint concludes that the destination endpoint is unreachable.