A first network node controls WLAN accesses and a second network node controls cellular network accesses. The first network node (NN) records a time of a last radio contact event of a user equipment (UE) with respect to a WLAN access controlled by the first NN. In response to a request from a third NN, the first NN indicates the recorded time of the last radio contact event to the third NN. The second NN records a time of a last radio contact event of the UE with respect to a cellular network access controlled by the second NN. In response to a request from the third NN, the second NN indicates the recorded time of the last radio contact event to the third NN. The third NN can use the indicated times to determine whether the UE is attached to a WLAN access or to a cellular network access.