A radio resource request in a radio access network (RAN) may be handled differently depending whether provision of the requested radio resource has been specified as optional (discretionary) or not optional (not discretionary). In the former case, the radio resource request may be discarded, rejected or delayed. In the latter case, the radio resource request may be accepted. In one embodiment, a running timer at a UE may indicate that a radio resource optionally to be provided was not provided by a RAN. When a subsequent request for the radio resource is accepted, the timer may be cleared. One or more UE applications may accordingly selectively subject user-plane data to be exchanged via the RAN, to a back-off delay scheme, to promoting acceptable responsiveness at UE applications that are, e.g. being actively used by a user. Radio resource requests may including RRC Connection Request and Cell Update messages.